Hi everyone, I installed a new u100 alliance rotor that my parents have had in the house in a box for years. The rotor is a four wire system (Found the wire online.) The control box died, is there a newer control box out there that will work with a 4 wire rotor.

Hi Folks,

I finally finished research, design, procurement, assembly, and installation of my new HD-optimized system. Many thanks to this forum.

I'm hoping that this might help some of the folks out there that are in a similar situation.

It's kind of a high-end system, as I was trying to bring in some pretty distant stations that my old CM-Quantum rig just wasn't capable of; although it was a very good antenna, especially for VHF.

Here's a picture (attached).

I'm in a deep-fringe area here in Northern California and this new rig pulls in 30 stations at the moment (mostly digital, up to 60+ miles). I expect 40+ digital channels when the Sutro-tower stations in S.F. finish moving their antennas up to the top of the tower and all the dust settles.

COMPONENTS & WEIGHTS:
TERRESTRIAL DIGITAL 91XG w/HARDWARE - 4.5 lbs.
BLONDER-TONGUE BTY-LP-HB w/HARDWARE- 8.5 lbs.
CM-9521A ROTOR w/HARDWARE - 7.5 lbs.
THRUST-BEARING (TB-105) w/HARDWARE - 2.0 lbs.
TIN-LEE UV-7X COMBINER w/HARDWARE - .25 lb.
RESEARCH-COMMUNICATIONS 9254 PRE-AMP w/HRDWR - .25 lb.
--------------------
23 lbs.

For coax; I went with LMR-400-75 from Times Microwave. Very low-loss coax; Did my own cabling with the TM EZ-400-FM-75 connectors, sealed with dielectric silicone grease and wrapped in coax tape. I bought a few tools to do the job correctly. It's about a 90 ft. run.

I picked up some unused, military-surplus, AIRCRAFT-GRADE ALUMINUM TUBING: 6063-T832 for the mast. Nice and light, very strong. It's up
about 35 ft.

It's a great rig that really pulls in signal well. On the higher-quality HD stations, it looks like I'm watching blue-ray...


- DFGY

It's kind of a high-end system, as I was trying to bring in some pretty distant stations that my old CM-Quantum rig just wasn't capable of; although it was a very good antenna, especially for VHF. Nice set-up!! How much difference do you notice on VHF with the Blonder-Tongue antenna? Which Quantum antenna were you using? Any reason you have so much slack between the bearing and the rotor?

Thanks, Glen

Nice set-up!! How much difference do you notice on VHF with the Blonder-Tongue antenna? Which Quantum antenna were you using? Any reason you have so much slack between the bearing and the rotor?

Thanks, Glen
Thanks Glen,

Difference in VHF: Well, you know how it is, there are lots of variables here. It's probably not all due to the antenna, but I can pull in an analog station (KSBW in
Salinas/Monterrey) that is well over 70 miles away; and it's watchable, although with
some snow... The old rig was very good with VHF, but it wouldn't pull this station in.

The BTY is a VHF-high only antenna, by the way. The Quantum was VHF-low and High,
etc. But, post-transition, I'll have no need for VHF-low in my area.

Which Quantum: The old rig was a CHANNEL MASTER QUANTUM 1162 (VHF/UHF/FM); 8.5db VHF/9db UHF
W/BUILT-IN 16db VHF-HIGH/23db UHF; It was the largest of it's type that was still UPS shippable...


Cable Slack: I guess I just wanted to make sure I had enough... It turns out that because I went so high, I had to attach guy's to the thrust-bearing and that means that the coax will touch the guy's at the top there, when rotated 180 degrees; which I don't need to do too often (there's only one station to the north). So, it actually worked out well. It rotates fine even though the cable does brush up against the top guy's.

- DFGY

Thanks DFGY,

Just in case anyone is interested, there is a show of possible interest tonight @ 6:00 eastern time on "THE NATIONAL GEOGRAPHIC CHANNEL". It is about an antenna crew working on a 2000' TV tower in South Dakota called "WORLDS TOUGHEST FIXES".

http://channel.nationalgeographic.com/tv-schedule#200812281800

The old rig was a CHANNEL MASTER QUANTUM 1162 (VHF/UHF/FM); 8.5db VHF/9db UHF
W/BUILT-IN 16db VHF-HIGH/23db UHF

Can you still get those cartridges? Back when I did residential, I used to dread being called to service systems with cartridge amplifiers because not only were they more difficult to reliably diagnose, if I thought they were bad then the customer would need to buy a whole new antenna.

You might want to scrounge around to see if you can get the matching terminal board, so that if you ever do have trouble with this amplifier cartridge, you can replace it with the terminator board and use an external preamp from then on.

The most common part to fail used to be the unpolarized capacitor. You could probably get a replacement from an electronics parts supplier.
John

Hi everyone, I installed a new u100 alliance rotor that my parents have had in the house in a box for years. The rotor is a four wire system (Found the wire online.) The control box died, is there a newer control box out there that will work with a 4 wire rotor.

AntAltMike,

I'm assuming you're referring to the built-in ChannelMaster amp that was in my old Quantum, which I took down, cut up with the sawzall, and placed in the recycle bin last week? Channel Master doesn't make the Quantum anymore; but the amp never failed in 10 years. It was a very good antenna; it just didn't have adequate UHF capability for the post-transition changes.

- DFGY

Does anyone know what typical insertion loss is on a Channel Master Join-Tenna? Here's the situation: All but one of the network-affiliate transmitters hereabouts are within 10 degrees of each other. The lone exception is the Ion affiliate, which is 65 degrees away from the "crowd" on RF channel 43. It's a 1-edge signal, so it won't lock unless the antenna is aimed right at it. When I aim for that station, all other stations lock, but at weakened signal levels close to the cliff. The best cost-effective solution is a second, dedicated UHF antenna. I currently have separate VHF and UHF antennas in the attic on a UVSJ with no amplifier.

Second question: How close is too close for nearby channels with a Join-Tenna? There's a local Class A operation on channel 39 I'd like to continue receiving.

Thanks DFGY,

Just in case anyone is interested, there is a show of possible interest tonight @ 6:00 eastern time on "THE NATIONAL GEOGRAPHIC CHANNEL". It is about an antenna crew working on a 2000' TV tower in South Dakota called "WORLDS TOUGHEST FIXES".

http://channel.nationalgeographic.com/tv-schedule#200812281800

It was first on about a month ago, it is the KDLT tower in SD, the tallest structure on the earth until the skyscraper in Dubai is completed... Very coooooool fix, one of the coolest things that I have watched on tv, I believe they swapped out the digital antenna, because it was at the top of the stack..... Let me know whatcha think!

I have a channel 52 jointenna which I checked out using my antenna as a signal source. The loss for the single passed channel was 5-6 dB. This same loss was seen on the other input for all channels three or more channels away from channel 52. The loss an the all channel input at channel 52 seemed to be 20 dB or more. Channels 49 and 54 were passed on either input with the 6 dB loss so could be view either way.
John

Does anyone know what typical insertion loss is on a Channel Master Join-Tenna? Here's the situation: All but one of the network-affiliate transmitters hereabouts are within 10 degrees of each other. The lone exception is the Ion affiliate, which is 65 degrees away from the "crowd" on RF channel 43. It's a 1-edge signal, so it won't lock unless the antenna is aimed right at it. When I aim for that station, all other stations lock, but at weakened signal levels close to the cliff. The best cost-effective solution is a second, dedicated UHF antenna. I currently have separate VHF and UHF antennas in the attic on a UVSJ with no amplifier.

Second question: How close is too close for nearby channels with a Join-Tenna? There's a local Class A operation on channel 39 I'd like to continue receiving.

I have a channel 52 jointenna which I checked out using my antenna as a signal source....

Thanks for the info, John. It's a big help.

I have a channel 52 jointenna which I checked out using my antenna as a signal source. The loss for the single passed channel was 5-6 dB.

It shouldn't be anywhere near that much. I measured several a few years ago, and I'm sure the bandpass channel signal loss was no more than 2dB on any of them.

FWIW, channel 52 is right around the "transition point" between the model 2 and model 3 units. I think one is tunable up to 49 and the other starts at 50, and I think that a few years before that, Channel Master used to use the model 2 up to channel 50 and the model 3 started at 51.

What do you have for a signal meter? The UHF Jointennas, unlike the VHFs, have two tunable slugs in them: one for the bandpass and one for the band rejection. I suspect that if you "tweaked" them, you could get a thru loss of a lot less than 6 dB.

I took a look at the jointenna and my aging memory needs correction, it is a channel 51 with 3 at the end of the model number. The signal sources were recieved signals from my antenna amd measurement was done using a Tektronix 451 spectrum analyzer. I also checked out an upper VHF jointenna it seemed to have a dB or two less loss but was still around 4 dB. Its notch was not as wide as a digital TV channel with over half of the channel passing intact. By comparision I have a VHF combiner from Tinlee and with my test set up I can see no loss on passed channels.
John

I have a channel 10 jointenna that we checked out recently (thanks, ctdish). The insertion loss was more than I expected on the "passed" channel (~4dB) and when we reversed it, the notch was rather sharp (not wide enough for the full channel). I don't plan on recommending these anymore after looking at its performance on the spectrum analyzer.

If WPRI and WNAC are granted 30kW on 12 and 13, I will probably have to get a good combiner. If they are not granted the power increase, it may not be worth my while as WPRI is so weak right now.

I have another jointenna in CA, for 31, but don't have a spectrum analyzer. However, I didn't notice much of a change in KTLA when I hooked it up, but then a 20dB attenuator hardly affects it as well (it is very strong).

From post #962

Well... exactly 1 month later I've got my antenna's up. The TB-105 bearing from Warren Electronics is NOT high quality. There is about 1/4" play within the bearing. The center of the bearing has flash in it which has to be sanded off if you intend to use 1 1/2" mast. I ended up buying a 10' piece of electrical conduit and cutting it in half. (seems to be stout enough)

The biggest problem is that the bearing sticks out from the mast somewhere between 1/4' and 1/2 " farther than the rotor which puts a serious bind on the rotor. I ended up having to make spacers to make the rotor match the bearing. The rotor works, but still has a little bind in it. When I have a chance to get back on the roof, I will further "tweak" the "spacers".

The good news is I am extremely pleased with the 91XG and a YA 1713 antenna's. I can now get a solid lock on KXII DT-20 (12) that tvfool shows to have a signal of -126.1 (2 edge) at 99.5 miles. :D


I haven't been here in awhile and did some catching up. This is exactly what happened to me. My first antenna installer did a poor job of the installation and my antennas came crashing down a year later. I got new antennas and a new antenna mast but I has decided to get the TB-105 bearing (I actually got 2 - 1 to use and 1 for a spare). just like you, I had to sand down the interior in order for the antenna mast to slide through. I got a second installer to put up the new antennas, and just like you - we found that the TB-105 bearing was about 1/4" off and when you rotated the antennas, that I had binding problem. Well, this set up lasted about something like 3-6 months, when the antennas were knocked down again (the antennas were not damaged this time). The installer then moved the rotor inside the tower between the 2 traingle plates and used a bearing from Wade (?) - this 3rd configuration is the best and works great for me.

I'm now stuck with 2 TB-105 bearings that are useless, what a waste of money.

I too was unable to use the single TB-105 I ordered so since my telescoping mast had no guy wire rings included with it I used the TB-105 to connect the guy wires---turned out to be the perfect use for it. Was originally going to use two 5-foot masts for my antennas with the TB-105 as the support but decided to use one 5-footer instead and so the TB-105 is now the guy ring.

I finally finished research, design, procurement, assembly, and installation of my new HD-optimized system. Many thanks to this forum.

Hi, DFGY. I sent you a PM. I am very interested in your experience with Research Communications. I live in a rural area where most of the towers are ~75 miles away. Fortunately, the antennas of those stations are ~1,500+ feet above the ground. My closet DMA is 60 miles. Unfortunately, its tv stations have much shorter towers, so their signals are somewhat weaker by the time they reach me. I need all the dB's I can squeeze out of my installation.

I look forward to your response to my PM.

As for any suggestions from other members, it would be greatly appreciated. I plan to have SEPARATE INSTALLATIONS for VHF (Funke PSP 1922 on a 40' mast) and UHF (Antennas Direct 91-XG on a 50' mast). Channel Master has discontiniued the UHF-only version of their pre-amps. Winegard's model has a slgihtly higher noise spec. I am considering a Research Communications model. Please see the attached TVFool png files. I split the difference in elevation & used 45' for my antenna height. I currently use a DB-8 for UHF (which may be having issues with multi-path from nearby trees) and a Winegard 7084 for VHF, combined with a Channel Master 7777 pre-amp with an elevation of 34'. Due to wind damage, last year, the current mast has a 3 to 5 degree tilt downward. Yeah, I know, that's certainly not a good thing. I can use help with planning my new installation(s). At least knowing I'm on the right track will help.

I took a look at the jointenna and my aging memory needs correction, it is a channel 51 with 3 at the end of the model number. The signal sources were recieved signals from my antenna amd measurement was done using a Tektronix 451 spectrum analyzer. I also checked out an upper VHF jointenna it seemed to have a dB or two less loss but was still around 4 dB. Its notch was not as wide as a digital TV channel with over half of the channel passing intact.

I just checked a channel 41 Joinenna and it lost 2.0 to 2.1 dBmV on its bandpass filter path, measured using an Applied Instruments white noise generator (NS-1?) and a Blonder Tongue BTPDA-4.

I wouldn't be averse to using a Jointenna just because it didn't pass a perfect plateau. Digital 8VSB signals are extremely robust, and rolling off a few dB at the channel edges will ordinarily have no deliterious effect on the processing of a healthy channel signal.

The real loser Jointenna products, which have been discontinued, were the lowband models. Some of them had less than ten dB of out-of-band rejection.

Rob, thanks for the location-specific report. Both TV and FM reports are arranged from strongest station to weakest. The top four, perhaps five, TV stations on the list are candidates with the CM amps, while the AP-8275 is likely to have issues handling the top six.

Hi Don,

Another question about something I'm seeing. I have two receivers, a Dish 942 and a Directv Tivo HR10-250, and they behave differently on some channels. I often can't get KGWN Cheyenne on the HR10-250, but it's usually fine on the Dish. Since I'm getting KGWN from the back of my CM-4228 and the aim is a bit wrong, I have explained this as simple multipath. I know the HR10-250 is older and likely to not handle multipath as well as the Dish unit. But something else occured to me today, related to more overload.

The channels which show the most variance between boxes are the ones closest to strong signals. I can get KMGH 7.1 (66%) and KGWN 5.1 (68%) fine on my Dish unit, and not at all on my HR10-250. (Nothing gets KUSA right now, though.) RF 29 (KDEN-DT) booms in at near 100% on both boxes, right next to RF 30 (KGWN). And RF 15 (KTFD-DT) is similar, and close to both RF 16 and 17 (KUSA and KMGH). Would a hypothesis that overload from these signals resembles multipath on nearby channels make sense? That would explain why otherwise-good reception conditions would go with a big variance between boxes. It doesn't affect channels further away - KRMA at RF 18 and KWGN at RF 32 are just fine, as usual. The HR10-250 actually does well with weak, clean signals - it gets 40.1 Daystar better than the Dish unit does.

BTW, that HDP-269 is on the way, and should be here by the end of the week :-) My hypothesis makes me more optimistic that it will solve a problem for me.

Rob T

Would a hypothesis that overload from these signals resembles multipath on nearby channels make sense?

The sources of overload and multipath are different, but because both involve signal distortion, the end result is the same -- poor or no reception. Multipath "confuses" the tuner with signals arriving at slightly different times (we're talking nanoseconds here) because of reflections. "Overload," which occurs in a pre-amp, tuner or both, distorts the signal waveform such that the tuner stumbles in the decoding process. It's a little bit like someone trying to get 50 watts' worth of music out of a 10-watt stereo: It sounds flat-out terrible thanks to the great amount of distortion involved.

Adjacent-channel interference isn't as much of an issue in DTV as it was in analog as long as transmitter spacing considerations are taken into account. For now, Denver actually has five adjacent DTV channels, and there are seven in a row if you count the analogs:

KTFD-TV 14
KTFD-DT 15 (14.1)
KUSA-DT 16 (9.x)
KMGH-DT 17 (7.x)
KRMA-DT 18 (6.x)
KTVD-DT 19 (20.1)
KTVD-TV 20

Of course, analog broadcasting on both 14 and 20 goes away in six weeks, and 16 and 17 will be vacated when KUSA and KMGH go back to VHF-high next month. That might not last forever, though: Syncom Media Group has dibs on channel 16 for a low-power digital once it's vacant, and KMGH owner McGraw-Hill has retained the right to do the same on channel 17.

It seems everyone here is preamp happy, but I will standby what I consider the best 'amp' available, the Winegard DA-1018.
Slight problem is it was discontinued some time ago and it very hard to find. BUT, someone on flea-bay has four of them for sale for $40 each (buy it now). Item #220342565969

I would get a couple, but I already have two spares for backup. ;)

1. No brick. AC line cord,
2. Used indoors where you can get at it,
3. High overload capibility unlike preamps that don't have any 'headroom' at all,
4. US made,
5. Aluminum case doubles as the heatsink.

There is a higher gain version of this and also two newer, less expensive models that appear to have identical circuit boards.

I need some help determining what preamp, if any I can use. My main concern is whether a few close FM stations are going to be a problem. If they aren't, I'd lean towards a Winegard HDP-269 since I'm just trying to overcome loss over a 50' RG-6 cable run from my antenna, and get a few stations I am getting now a little better. If I need an FM trap, I was leaning towards an AP-8700. I currently am using a DBGH, but could substitute it with a SBGH if a gain of a few less dB would help the situation.

Thank you for any advice in advance!

Craig

I need some help determining what preamp, if any I can use. My main concern is whether a few close FM stations are going to be a problem.

It really depends on your antenna. An all channel antenna (2-69) would pick up FM very well and would overload most preamps. A 7-69 antenna would not receive FM well. Such an antenna would make it easier to select a preamp.

The HDP-269 does not have an FM trap.

The AP-4700 or AP-4800 does not amplify VHF and should work.

I need some help determining what preamp, if any I can use. My main concern is whether a few close FM stations are going to be a problem. If they aren't, I'd lean towards a Winegard HDP-269 since I'm just trying to overcome loss over a 50' RG-6 cable run from my antenna, and get a few stations I am getting now a little better. If I need an FM trap, I was leaning towards an AP-8700. I currently am using a DBGH, but could substitute it with a SBGH if a gain of a few less dB would help the situation.

Thank you for any advice in advance!

Craig

Your FM levels are not that high, go with the HDP-269, it will work out fine... I have a 100kw station at 6 miles, it does not overload, if my antenna is not directly facing it, that is a VHF antenna, UHF, not enough gain to be a problem...

Your FM levels are not that high, go with the HDP-269, it will work out fine... I have a 100kw station at 6 miles, it does not overload, if my antenna is not directly facing it, that is a VHF antenna, UHF, not enough gain to be a problem...

What FM levels do cause a problem with a preamp?

Forgive me if this was discusse long ago in this thread but I am thinking about using a VHF antenna that does cross the FM band to get down to TV channel 6 and one strong radio station -17.5 dBm is nearly in line with some other TV stations.
What are the considerations for requiring the FM trap needs to be in the preamp? Would a distribution amp with an FM trap be about the same? Will I still get enough FM radio reception using the TV antenna for distant listening when using the FM trap? Any advice?
Thanks,

The AP-4700 or AP-4800 does not amplify VHF and should work.

In reality the GH antenna I am using is mainly a UHF antenna. I can pick up strong VHF hi stations (WHTM for example), so I wouldn't mind amplifying them in the hopes of picking up WJZ after the transition (moving to Real 13). My main use of the preamp is to get some of my more distant UHF stations I'm getting now with a more reliable signal, especially during foul weather. I just didn't have an inkling of how strong an fm station has to be to muck things up and whether it really mattered using a GH antenna.

Thanks for the help -- I think I'll go with the HDP-269.

Craig

In reality the GH antenna I am using is mainly a UHF antenna. Thanks for the help -- I think I'll go with the HDP-269.


That should be OK.

What FM levels do cause a problem with a preamp?

Thanks,Levels stonger than -40 or so may cause issues with a high gain pre-amp. (The HDP-269 is much more forgiving) My general recommendation is to try the pre-amp with the trap on, then off and see if it makes a difference. Also keep in mind that the internal FM trap does not attenuate the lower end of the FM band very well. (Because of issues with channel 6) If you have strong stations below 92 MHZ on the dial, you may need an external trap "before" the pre-amp that attenuates the "entire" FM band. My FM interference is strong enough that I need a full band trap to attenuate a station with +11.7 db even with no pre-amp. It makes a world of difference.:)

Levels stonger than -40 or so may cause issues with a high gain pre-amp. (The HDP-269 is much more forgiving) My general recommendation is to try the pre-amp with the trap on, then off and see if it makes a difference. Also keep in mind that the internal FM trap does not attenuate the lower end of the FM band very well. (Because of issues with channel 6) If you have strong stations below 92 MHZ on the dial, you may need an external trap "before" the pre-amp that attenuates the "entire" FM band. My FM interference is strong enough that I need a full band trap to attenuate a station with +11.7 db even with no pre-amp. It makes a world of difference.:)

Digital Rules is spot on, I would have posted about the same info!

Levels stonger than -40 or so may cause issues with a high gain pre-amp. (The HDP-269 is much more forgiving) My general recommendation is to try the pre-amp with the trap on, then off and see if it makes a difference.

Update:
Ok, I did not order the HDP-269. It doesn't have an FM trap, and I have 2 FM stations stronger than -30dBm, and 8 in the -40 to -50 dBm range. I ordered the AP8700. I'm glad that I did. Without the FM trap, I only picked up my strongest stations. With it on, it works very well. It makes the UHF stations I get from Baltimore almost drop-out free (maybe a few an hour in bad weather), and increases the strength of every other channel I receive without apparent overload problems.

The HDP-269 may have been fine, but at twice the price of the 8700, I figured I'd take the chance with the stronger preamp. I did somewhat cheat; I had someone who would have bought the 8700 off me if it didn't work out...

I was wondering if you would suggest the Winegard hdp-269 or the ap8700 for my situation. I get decent signal from my antenna when it is run to one television. The problem is it needs to be split and run to 3 more with runs of 20, 30, and 50 feet. I am thinking the hdp-269 may be the best given the fairly strong signals I have, but wanted to check to be sure. Attached are my fmfool and tvfool plots. Thanks for any advice.

I was wondering if you would suggest the Winegard hdp-269 or the ap8700 for my situation.

One thing is clear, you need an FM trap. If you opt for the HDP-269, an external trap is called for.

The other question is what stations are you trying to receive? The green stations are strong enough to be split even without a preamp. The pink stations will need a preamp. The HDP-269 does not have enought gain for the weaker pink stations. The FM trap in the AP-8700 doesn't have as much rejection of FM stations as a stand-alone trap such as the FT7500. The FT7500 will not allow you to receive channel 6.

I am only looking to get the green stations. I unfortunately am fighting through some trees and it is an attic install (as dictated by the DW) so my situation is not quite as easy as it seems. I am able to get good stable reception with one television or even with a single 2 output splitter, but I cannot get stable reception on the 2 farthest televisions once they are split again. The main problems I am having are with real channels 39 and 47, but also occasionally with 8 and 10.

Would I be better off getting something like the CM3414 distribution amp and hooking it up to only the offending television runs and leaving the others alone?

I am only looking to get the green stations.

That suggests an HDP-269 with the external FM trap. The AP-8700 would work if the tunable trap were adjusted to minimize the strongest FM station.

Last question . . . I think . . . would you recommend the ft7500 as the trap to get or is there one that I am likely to find locally (such as radio shack) that will work as well? Thanks.

Is there a trap that I am likely to find locally?

Then Radio Shack web site doesn't show any FM traps. Yours may have one sitting around from years ago.

If you have an electronic parts store nearby you can call and ask.

Anyone know where I can pick up a Funke PSP.1922? Are they still making these?

- DFGY

Anyone know where I can pick up a Funke PSP.1922? Are they still making these?

- DFGY

I'm sold out.The company in Holland may still make up a batch.They wanted a minimum 100 unit order at the time I ordered them,but they settled at 49 units when we BS'd about Pacer basketball(Rik Smits is from Holland).The export mgr done follow-up calls to me several times,so they seemed eager to do export business.

Or,maybe someone I sold to has one that didn't work out and sees your post?

MAX HD,

Maybe you should consider becoming the official US distributor for Funke. Maybe not the entire line, only the antennas useful for DXing and fringe.

MAX HD,

Maybe you should consider becoming the official US distributor for Funke. Maybe not the entire line, only the antennas useful for DXing and fringe.

Nope,too much hassle and too expensive.The air freight alone on those 49 was $850 and had to drive 50mi to pick them up.Not to mention it took a week to find out where they were so I could pick them up.And guess who had to pay the daily dock storage fees,customs fees,and some other foo-foo fees? When you buy from overseas,there's several entities that people are unaware of that you must hand over money to,to get the merchandise.

Anyone know where I can pick up a Funke PSP.1922? Are they still making these?

- DFGY
Thanks,

I sent them an email last week, but no reply... Maybe Terrestrial Digital will copy it and offer it to the U.S. market? :)

- DFGY

As many of you know, I've been trying to get my antenna system up and running for a while. I've got an FM antenna, Wade UV-936SR and a DBGH UHF antenna on top of a hill behind my house. TV Fool tells me all the signals I'm after aren't lower than -85 (most all are in the red zone).

I had tested the DBGH before and it got me Twin Cities analog UHFs perfectly from a site about a mile from my house (75 miles from the tower) and at a lower elevation. I was using a prototype and a different balun.

After much work, I finally got the thing on top of the hill. The DBGH was over 25 off the ground. It was fed into the UHF side of a VUSJ. The Wade 936 was fed into the VHF side. The signal goes down to the house through about 250ft of RG-11.

Aimed directly at the TC, their UHFs were very fuzzy color, and VHFs started out nearly perfect on ch. 2 and look atrocous by ch. 11 (which is low power).

I removed the pre-amp so it went directly down to the house, lost the UHFs and had my VHFs get a little worse. I then put the pre-amp back in and Connected it directly the DBGH. The same. I connected the pre-amp directly to the Wade 936 and got slightly worse TC UHFs, but gained better reception on stations in other directions.

I've also tested my FM antenna. While I get super reception on in-town stations, TC stations (all of which are 100KW) are rather fuzzy.


We've tested the resistance of the RG-11 (shorted at one end) and it measures 1.2ohms (or something really low like that). We replaced the ground block, replaced all RG-6 and connectors going from the block to pre-amp and the DBGH (need to re-do the one on the Wade). We've sanded every center conductor to remove any trace of gunk and measured resistance.

I've been scratching my head over this for weeks, and I think I finally found the culprite. The Baluns.

I'm using Phillips Magnavox baluns on all my antennas. They look to have chincy construction (only a few strands of wire in the twinlead part), etc... I'm thinking of splurging and getting three Channel Master baluns from Summit Source, but I want to know your opinions. Has anyone had experience with the Phillips Magnavox baluns? Has anyone done a comparison with other models? any low-loss DIY designs?

If all else fails, I might try a 300ohm pre-amp. Any idea where to get, say shielded twinlead?

Thanks,

I sent them an email last week, but no reply... Maybe Terrestrial Digital will copy it and offer it to the U.S. market? :)

- DFGY

I actually have thought the same thing. I have even considered send them an email or calling them to suggest it. Terrestrial Digital has an RV they are touring the country with pushing their antennas at TV stations during the local news in preparation for the transition. At one of the stops the founder did an interview where he stated he only founded the company in 03. His friends told him he we crazy. He just felt that as HD programming grew people would have a desire receive it free as opposed to paying an additional fee to the cable companies. The 91XG does exactly as advertised. It would be nice if they offered a deep fringe VHF high to accompany it.

I actually have thought the same thing. I have even considered send them an email or calling them to suggest it. Terrestrial Digital has an RV they are touring the country with pushing their antennas at TV stations during the local news in preparation for the transition. At one of the stops the founder did an interview where he stated he only founded the company in 03. His friends told him he we crazy. He just felt that as HD programming grew people would have a desire receive it free as opposed to paying an additional fee to the cable companies. The 91XG does exactly as advertised. It would be nice if they offered a deep fringe VHF high to accompany it.
Ditto! I have a 91XG and it's a very close copy of the Funke DC4591.

http://www.avsforum.com/avs-vb/showthread.php?p=15395903#post15395903

Maybe if they get enough emails, they'll consider it...


- DFGY

Ditto! I have a 91XG and it's a very close copy of the Funke DC4591.

http://www.avsforum.com/avs-vb/showthread.php?p=15395903#post15395903

Maybe if they get enough emails, they'll consider it...


- DFGY

I doubt it.I give Funke's export mgr Richard's phone number 3-4yrs ago and nothing happened.Apparently better profit opportunities getting stuff from China.You're right about the copy of the DC4591.According to Funke they designed it and many other countries copied it,not exactly,but the end results are the same.Very good design with better bandwidth,better F/B than any other UHF antenna.

I have a question for thos technically versed on preamps. I have heard everyone talk about the channelmaster pre-amps having a much lower noise figure than the radio shack models. I have a radio shack model (15-2507) and it has served me well for 12 years. I purchased a channelmaster 7775 a year or so ago, and tested it with my analog UHF stations. I did this over three of four days, with back to back testing... and it performed just as well as the radio shack, but no better. There was no discernable difference in the analog picture between the two amps. (I expected maybe slightly less snow, etc..)So I sold the channelmaster on ebay. Now, I've read some places that the lower noise figure makes more of a difference in digital reception... exactly what kind of difference? Does it make the channels you already have more stable with less droupout? Or does it make weak stations lock on easier at lower signal strength? What is the technical advantage of the lower noise figure in digital? And on a very marginal channel that is right on the edge of coming in (maybe locks on at night, but not during the day) might that lower noise figure make an appreciable difference? I might try the 7775 again with digital, but I'm leery, because every channelmaster product I've purchased has not performed up to expectation, and in some cases (like my channelmaster quantam 1160) the radio shack product out performed it by an appreciable distance.

mattdp:
DIY Coax Baluns were just discussed in DIY UHF Antenna thread:
http://www.avsforum.com/avs-vb/showthread.php?p=15837159
The Canadian Balun thread has additional discussions....

And earlier, I posted Balun Loss measurements in this thread:
http://www.avsforum.com/avs-vb/showthread.php?p=13581150

I'm using Phillips Magnavox baluns on all my antennas. They look to have chincy construction (only a few strands of wire in the twinlead part), etc... I'm thinking of splurging and getting three Channel Master baluns from Summit Source, but I want to know your opinions. Has anyone had experience with the Phillips Magnavox baluns? Has anyone done a comparison with other models? any low-loss DIY designs?

If all else fails, I might try a 300ohm pre-amp. Any idea where to get, say shielded twinlead?

I am using both the CM and Phillips baluns at present, signalwise I don't have any real horror stories on either. The heavier construction and weatherproofing on the CM make them nice units for the antenna end. Back in the 70's when I was much closer to your age and I put up my first TV antenna I wanted the best and used shielded 300 Ohm twinlead which was a R-S item in those days (I think they had 3-4 grades of 300 ohm twinlead). Nice stuff although hard to work with (stiffer and fatter than coax), had a foam core between the wires and foil shielding. I later came to find out that it was really for protection from external impulse noise problems and had worse attenuation specs than the cheap stuff.

Did you ever measure the PS voltage at the antenna preamp under load from the wall supply? I know the connections are clean and you know the resistance of the RG-11 but it is still possible you aren't getting enough voltage at the preamp though all the wire, baluns and connections to get the best gain from your preamp. Maybe even trick out some F connectors and measure the current with a VOM under load. You could be getting a lot of voltage drop or have a poor power supply on the CM7777. Just a thought, it looks like you covered most of the other bases. I know it's a hard climb for you up and down that hill!

I'm using Phillips Magnavox baluns on all my antennas. They look to have chincy construction (only a few strands of wire in the twinlead part), etc... I'm thinking of splurging and getting three Channel Master baluns from Summit Source, but I want to know your opinions. Has anyone had experience with the Phillips Magnavox baluns? Has anyone done a comparison with other models? any low-loss DIY designs?


I had been using Phillips/Magnavox (Lowes) and RS baluns until last week. I placed and order for 5 Model 0089 CM Balun/Matching Transformers. I have a DBGH on the roof, and a SBGH 10 strapped to the porch. The DBGH came down in a fit of wind, so I took the opportunity to replace the Phillips balun with one of the CMs. I noticed the difference right off the bat. Not only are my signal strengths better, but they don't seem to vary so much in windy/rainy weather (Some of that could also be my thicker/sturdier mast). I did hook up all 5 to my SBGH on the porch, and ended up rating them from 1 to 5. There was a difference between each...it could have been changing conditions, but I tried them 1 thru 5 then 1 thru 5 again, and the results matched between each trial. The CMs were better than the other two in both sets of trials, with the RS being the worst.

I know that isn't real scientific data, since I have nothing to measure it with meter wise, but logically it seems to prove that the CMs are better than the other two, and at a few dollars a piece, I think it's a good investment!

Now, I've read some places that the lower noise figure makes more of a difference in digital reception... exactly what kind of difference?

I haven't used any RS preamps,but I'm sure they've had some decent ones in the past.I've used CM,Winegard,Blonder-Tongue,Research-Com,and Emcee.The lower noise(.5db) seem to work slightly better,but the margin is very small.If you expect to bring in those night-time receivables at 2 PM the next day,dream on-ain't gonna happen.It will take much more than the preamp alone because the signal is basically"not there".Large stacked arrays on a very tall tower,then maybe,but no guarantees.

The pre-amp question can be complicated by so many factors.

With regard to noise figure and digital reception, and keeping everything as simple and straight-forward as possible, the reason it makes more of a difference is because of the all-or-nothing nature of digital.

Say for example you had a signal coming out of your antenna that was 20 dB above the noise floor. If you use a pre-amp with a 3 dB noise figure, you might retain enough signal-to-noise headroom to get a lock and decode a perfect picture. If you use a pre-amp with a 6 dB noise figure, you might end up with no picture at all.

With analog, that 3 dB difference in noise figure would make a significant difference in picture quality, but you'd still get something. With digital, it's the difference between a perfect picture and nothing at all.

That is a drastic over-simplification, but hopefully that will give you an idea why people might say noise figure makes more of a difference with digital (a statement I don't necessarily agree with).

With Analog you can crank the attenuator over a fairly wide range from OKAY to NOGO.
Digital has a much narrower range going from OKAY to NOGO....and is very noticeable
when there are intermittent dropouts...vice Analog which is fuzzy anyway you look at it.

Thanks everybody for the information. I will most likely be ordering CM baluns and (hopefully) getting a new Winegard AP-8780 with power supply, etc... One of these days IT WILL WORK PROPERLY. Even if it doesn't, 2 CBS, 1 MyNet, 1 CW, 7 PBS Subs and 2 Fox really isn't too bad for our viewing needs.

Which preamp would you be able to recommend for my sister. She is located LOS 14 miles from the transmitters, lots of tall oaks in the back yard, but is getting good reception on some channels and spotty drop outs on others. Set up: 3rd floor attic pointing through glass window toward antenna farm... RS U75R antenna ....75 feet or more of cable. Antenna feed is going into the coax input of a dvr/vcr unit, and then into the TV. Signal seems to be bouncing up and down on some channels - especially with the wind.. when signals are stable she is at 1/2 to 3/4 on the signal bar... Could a winegard HD269 help? Seems she might need a little more gain due to indoor mount and long cable run.... any thoughts, I don't want to overdrive the signal being 14 miles away.

Thanks

Which preamp would you be able to recommend for my sister. She is located LOS 14 miles from the transmitters, lots of tall oaks in the back yard, but is getting good reception on some channels and spotty drop outs on others. Set up: 3rd floor attic pointing through glass window toward antenna farm... RS U75R antenna ....75 feet or more of cable. Antenna feed is going into the coax input of a dvr/vcr unit, and then into the TV. Signal seems to be bouncing up and down on some channels - especially with the wind.. when signals are stable she is at 1/2 to 3/4 on the signal bar... Could a winegard HD269 help? Seems she might need a little more gain due to indoor mount and long cable run.... any thoughts, I don't want to overdrive the signal being 14 miles away.

Thanks

No splits? If not, on that run of cable the signal could be too strong even with lower gain, HDP-269 amp... Sounds a lot like multipath to me... I would not bother with the amp at those distances, unless it is being split 4+ times.. Maybe a low gain/low noise distribution amp at best... Some tuners can handle multipath better then others, which is she using?

she is running the RG6 quad into a Panasonic DMR-EZ47V and then into the tv input (Phillips 32PF7421d/37) -LCD - I just had to upgrade her software yesterday for the TV... everytime they turned it off, the OTA channels wouldn't save in memory. Turn it back on, and the channels disappeared - for those growing up in the 70's like me, it was like a "close and play".

dbm's are -26.1 to -51.2 and db's are anywhere from 39 to 64.5

here is the TV fool results for my sisters location

A preamp will likely cause more harm that good. Try adjusting the pointing angle of the antenna and maybe even moving its location inside the attic.
John

Hi All,

I searched about a bit and I don't know if this question should be posed either here or in the AVS Antenna thread. Anyway, here goes:

I'm wondering what my best antenna/pre-amp setup would be for my situation.

- I'm pretty close to the towers.
- My house sits on the side of a hill. This hill blocks most of the directions I need to point to hit the main group of towers from which I want to pull my stations.
- I'm completely surrounded by large trees and homes.
- I had a smaller UHF only antenna on my roof, but recently lost almost all reception because of an ice storm. It's been too cold for me to get back up on the roof to fix the damage.
- Plus, I know pretty much for sure that I did little to no weather-proofing of my connections, so I'm sure I'll have to re-do a lot of stuff.
- I have about a 100 ft cable run from the antenna to the TV.

Whenever I go to antennaweb.org or tvfool.com, they show that most of my local stations are close enough to only require a green indoor antenna. However, based on my tree and hill/building problems, I think these aren't true. (I've attached the tvfool map as a reference)

What would everyone recommend I get for an antenna to receive high VHF and UHF? Would I also need a pre-amp (like a CM7777??) to boost signals that too weak because of the hill/trees and cable length??

Thanks for any help you can provide,

-BL

Please also show us what post transition looks like for your exact address.
We could do it by zip, but since you have a hill exact address is better. By coordinates is the most accurate, usually.

Well, it's funny. I live in Providence, RI and the local PVD stations have transitioned, but the Boston stations which I can receive pretty well, have not yet transitioned. So I'm sorta 1/2 transitioned. ;-)

I've attached another map from antennaweb. In this map, N. Main Street runs along the bottom of the hill. Summit street runs along the top of the hill (ironically enough). The stations I want to reliably pull in are along the 'A' direction along the side of the hill and in the 'C' and 'D' directions, which are directly into the side of the hill.

134618

Anyway, my coordinates are:

Latitude
41.851666 °
N 41 ° 51' 6.0"
41 ° 51.1000' (degree m.mmmm)
Longitude
-71.400200 °
W 71 ° 24' 0.7"
-71 ° 24.0120' (degree m.mmmm)

Please also show us what post transition looks like for your exact address.
We could do it by zip, but since you have a hill exact address is better. By coordinates is the most accurate, usually.

Your stations are too strong for a preamp. Overload will do more harm than good. Which stations were giving you trouble? With the blockage multipath could be a problem. The solution is a moderate gain antenna to reject the other paths. If you want to get stations from almost 90 Deg. apart you will need a rotator. You also have several VHF stations so if these were giving you trouble a high VHF antenna might also be needed.
John

Thanks ctdish. Can you, or anyone else for that matter, make any recommendations for an antenna that would meet my needs??

TIA,

-BL

Your stations are too strong for a preamp. Overload will do more harm than good. Which stations were giving you trouble? With the blockage multipath could be a problem. The solution is a moderate gain antenna to reject the other paths. If you want to get stations from almost 90 Deg. apart you will need a rotator. You also have several VHF stations so if these were giving you trouble a high VHF antenna might also be needed.
John

One of the WINEGARD HD-769 Series would probably be a good choice. You can see pictures here http://www.starkelectronic.com/allant.htm
The larger ones will provide slightly more signal but more importantly will reduce the amount of multipath. The down side is cost, size and the the fact that the antenna will need to aimed more precisely. If you desire stations that are 90 deg apart none will work well without turning in the desired direction.
John

Brian post transition

I'm trying to help my family get set up for the transition. They're about 60 miles outside of Boston, which is the primary broadcast location. I'm attaching plots for post-transition digital and FM reception. My question is which preamp to use? There's only one channel that even starts to come into the green. If I go with the high gain of a Winegard AP-8275, am I safe from overloading anything? The antenna is roof mounted on a 2-story house. I'm not sure exactly what it is though. It's a VHF/UHF in the style like an HD7015, but would have been something purchased from RS or Sears 15-20 years ago. (It's about an hour away, so I haven't had a chance to just drop by, climb up on the roof and check it out closer). There will be about 50 ft. of quad shield cable before being split to two TVs. The goal is to try to get everything on the chart down to WBZ, but I'm not sure if that is realistic.

I'd appreciate any advice on the preamp, or even changing the antenna.

thanks,

-Dave

Hi All,

I searched about a bit and I don't know if this question should be posed either here or in the AVS Antenna thread. Anyway, here goes:

I'm wondering what my best antenna/pre-amp setup would be for my situation.

- I'm pretty close to the towers.
- My house sits on the side of a hill. This hill blocks most of the directions I need to point to hit the main group of towers from which I want to pull my stations.
- I'm completely surrounded by large trees and homes.
- I had a smaller UHF only antenna on my roof, but recently lost almost all reception because of an ice storm. It's been too cold for me to get back up on the roof to fix the damage.
- Plus, I know pretty much for sure that I did little to no weather-proofing of my connections, so I'm sure I'll have to re-do a lot of stuff.
- I have about a 100 ft cable run from the antenna to the TV.

Whenever I go to antennaweb.org or tvfool.com, they show that most of my local stations are close enough to only require a green indoor antenna. However, based on my tree and hill/building problems, I think these aren't true. (I've attached the tvfool map as a reference)

What would everyone recommend I get for an antenna to receive high VHF and UHF? Would I also need a pre-amp (like a CM7777??) to boost signals that too weak because of the hill/trees and cable length??

Thanks for any help you can provide,

-BL

I too am in a similar situation except my location doesn't have many stations. My TV Fool chart looks pretty dire and I'm not sure I'll ever be able to receive Digital OTA at my home anytime soon. I'm wondering if it would even be worth the time to find out. Any advice would be appreciated

Attached is my post transition digital tvfool chart.

Latest FCC database reportedly has lots of (new) errors which were reflected in
www.tvfool.com reports. TVFool reverted to older, more believable database.

Rerun tvfool if you ran it within the past couple days.

dsaar:

The AP 8275 will not overload at you location, so you'll be OK using it. The CM 7777 has 0.8 dB lower NF than the AP 8275 on UHF; so it may be better on those low signal levels.

As for getting down to WBZ, signal levels with negative Noise Margins are very difficult to get. So I wouldn't bank of getting a steady and drop-out free picture.

Last, your signals come in from different locations so you'll need to align your antenna towards the stations you'll want to receive. A rotor can do the job.

YUL-STL

DSAAR

I have a similar situation to the one you are trying to set up.

I am 63+ miles from the stations I want to receive and am currently receiving a station with a Noise Margin of -15.3 (KUSA-DT). I seem to have a more severe shadowing issue than you have.

I am using a Winegard HD9095P UHF antenna with about 14.5 dB gain on real channel 16 (9.x) running into a Winegard AP8275 Pre-Amp. I also have an old Winegard VHF antenna with similar? gain numbers. I actually believe that the 8275 is overloading on channel 35 (4.1) that is now at full post transition strength and I may go to a lesser Pre-Amp when the full transition occurs.

With your VHF/UHF station mix, you will need a combination antenna.

I am presently receiving KUSA-DT with good signal strength and the only time I see a dropout is when a bird lands on the antenna or the wind blows 20 - 30 MPH and causes the antenna to move around.

I'm attaching my TV Fool Radar plot for the present time as well as my shadowing profile and your shadowing profile for WBZ.

Good luck
John

I live in rural NW Wisconsin. I am 61 miles due south of the Duluth, MN antenna farm and 72 miles from the Twin Cities antenna farms at Shoreview.

I inherited a 50 Rohn tower, VHF, and UHF antennas from my sister. When I took it down I noticed that the large UHF antenna had never been hooked up. The Channel Master preamp had only a VHF input so I figured they just said the hell with it.

I can get VHF digital signals just fine but no UHF. I need a good preamp that does both VHF & UHF.

Any recommendations?

The Channel Master 7777 is pretty much the standard one for situations such as yours. It has high gain and low noise, and separate inputs for VHF and UHF. I use one myself, with most stations ranging from 50 to 75 miles in various directions.

Do you also have a rotator? If you don't, you'll need one. If you're currently getting stations form only one direction, you should use tvfool.com to check predicted signal levels to make sure you have a chance of receiving the stations from the other direction. Save the table (it's a PNG image) on your computer, and attach it to a post here, and people will be able to give more specific advice.

I do have a rotor. I get the Twin Cities analog just fine as well as Duluth. It's just that I'm needing a VHF/UHF preamp.

I looked at the CM7777 and noticed that it has a switchable option for combining the signals into one input or running seperate cables from each antenna to their appropriate inputs on the preamp. Which hookup gives the best results?

According to

http://www.channelmasterintl.com/amplifiers.html

the 7777 amplifies VHF and UHF separately, so it wouldn't make any sense to combine the signals from separate antennas and feed them into the "combined" input, because the 7777 will simply separate them again. You'd lose a little signal at each of the combining and joining steps.

Since you have separate VHF and UHF signals to begin with, use the separate inputs. The switch inside the box is set for combined input by default, probably because most people use combination VHF/UHF antennas. So don't forget to open up the box and set the switch. I had to do that when I upgraded from a combo antenna to separates.

the 7777 amplifies VHF and UHF separately

Yeah. I still wonder why they did that, it does have separate F connectors. Maybe it could be hacked so you could have a vhf and uhf input at the same time like on my CM0264. It would make a lot more sense then.

Yeah. I still wonder why they did that, it does have separate F connectors. Maybe it could be hacked so you could have a vhf and uhf input at the same time like on my CM0264. It would make a lot more sense then.

Uh, the CM7777 already does accept VHF and UHF input at the same time. It has 2 75-ohm inputs and a 75-ohm output.

Yeah. I still wonder why they did that, it does have separate F connectors. Maybe it could be hacked so you could have a vhf and uhf input at the same time like on my CM0264. It would make a lot more sense then.

The use of two separate amplifiers, one for UHF and one for VHF, significantly reduces the possibility of overload.

I was given an old antenna (I believe it is a VHF/UHF/FM antenna, about 10 ft long and the arms expand out to 8 feet, and the arms are U-shaped) that was laying in a field for quite some time. It had a pre-amp that has exposed to the elements, and the connection from the antenna (rusted, and can not move the nuts) to the pre-amp is in bad shape. This antenna is in the attic (about 12 feet off the ground, and there are no windows in the attic), with very little room to move. I have it pointed in the general direction of the stations. I have attached the TV Fool map and I am aiming at the stations in the SE.

Right now I have flat wire stipped and wrapped around parallel wires (???, not really wires but connect the u-shaped arms to each other, and these wires are about 1 inch apart) I have purchased a pre-amp (RCA, not sure of the model number). I have one splitter and the cable run is less than 50 feet. Right now I can not pick up any TV stations (digital or analog).

I have a few questions:

Since the old connections from the antenna are so badly rusted, I was wondering where I can attach either flat wire (2 wire) or Coax to the antenna?

Is the pre-amp required?

Will I even be able to pick up any stations?

A few photos of the antenna might help.

At this time I do not have access to the antenna to get pictures. Here is a link to a pdf. On page 3 of the pdf document, fig. 1-6, the u-shaped arms are what the antenna has, and the rest of the antenna looks like fig. 1.5.
Fig. 4-3 basically shows how I have the antenna in the attic (except mine is not anchored, just laid on the rafters). Fig. 9-2 shows a pre-amp, attached to the antenna. The rusted out connections that are currently on my antenna are un-usable. I was wanting to know where another place to connet to the antenna might be located.

The only place to connect your lead-in cable is to the connection screws and nuts or the active element or elements they are connected to. Anywhere else and you are shorting the ends of your cable together. I guess you have cut loose the old pre, you don't want the antenna double terminated. I would work on those connection screws or the antenna is probably worthless. I couldn't read the image; looks like you are somewhere near Springfield, MO. You can get on a Radio Shack web site and find the approximate range for an antenna with that boom length.

The only place to connect your lead-in cable is to the connection screws and nuts or the active element or elements they are connected to. Anywhere else and you are shorting the ends of your cable together. I guess you have cut loose the old pre, you don't want the antenna double terminated. I would work on those connection screws or the antenna is probably worthless. I couldn't read the image; looks like you are somewhere near Springfield, MO. You can get on a Radio Shack web site and find the approximate range for an antenna with that boom length.

Thanks for the info. I did remove the old pre, and added a new one. I will try and work on the connection screws (the are pretty rusted though). I guess i could try to solder the lead-in cable to the rusted connection and see if that helps.

Thanks to those who replied to my original message, (02/26/09). To recap, the basic problem is bad digital reception at my relatives house about 60 miles outside of Boston.

I decided to go with the CM 7777, and after receiving it and some other parts, finally got a chance to install it the other weekend. The result was the best analog reception I've ever seen there, but only the top 3 channels, (from the TVFool chart), when I switch to digital. So the question is what next?
After spending some time with the antenna, it looks a lot like a CM 3018. Is there much hope that upgrading the antenna to something like the HD8200 would make much difference? Is it safe to assume that as long as you're making a good connection, the age of the antenna doesn't matter? Post transition, the next two target channels are real 7 and 9, so it can't just be a UHF solution. Are there other tips and tricks I can try?
It's frustrating because the analog picture is now very good. I suspect that if I can't get this to work with a somewhat educated effort, there are a lot of other people who's reception is going to go dark this summer.

Your chart is showing levels of stations that would be very difficult to receive where I live. You might try running TVFool with the height set to 75 feet and see if a larger mast or tower would be helpful. Which analog channels now look better VHF, UHF or both? If you don't have too much snow there is hope for the similar digital channels. The CM 3018 looks like a pretty good antenna. That said better UHF antennas can be had but you could keep the 3018 for VHF.
John

I too am in a similar situation except my location doesn't have many stations. My TV Fool chart looks pretty dire and I'm not sure I'll ever be able to receive Digital OTA at my home anytime soon. I'm wondering if it would even be worth the time to find out. Any advice would be appreciated

asg1290,

I think you could get all the stations at 8.2 miles, if you use a Channel Master CM3020 antenna (http://www.solidsignal.com/prod_display.asp?PROD=ANC3020) and make sure you point it at the horizon (skyline). You may need to add a pre-amp. Install the antenna first and order the pre-amp later. Make sure it has a very low Noise Figure (NF).

I'm at 60+ miles with 2-edge reception and signal levels much lower than yours (-100 to -124). I'm using a CM3020 that is 15 years old.

Hi,

I'm totally clueless when it comes to a/v concepts. Can someone explain to me why I can't use a tunerless DVD/VCR to record from an ATSC digital TV? I wasn't able to record with the antenna connected to the VCR, so I connected the antenna to the TV and then RCAs connecting the DVD/VCR to the TV. I got no signal that way either; it recorded black & grey noise.

I'm just totally confused. I don't understand the concept of the signal, where it's coming from, etc. Why doesn't the DVD/VCR pick up the TV's digital signal? If I could understand the concept, I might be less confused.

Thanks,
Bonnie

When you use RCA cables, the source will be the DVD/VCR. This feeds the television "Baseband" information. The television generally doesn't transmit, except for audio (Red & White jacks), which will usually go to a sound system of some sort.

A "tunerless" device will always need some sort of attached unit like a Cable box, Satellite receiver, or Terrestrial (OTA) receiver (like a CECB).

If you have a HDTV, you may be interested in one of these Terrestrial boxes:

DTVPal DVR (http://www.ezdigitaltv.com/DTVPal_DVR.html)
Coby DTV-140 (http://www.ezdigitaltv.com/Coby_DTV-140.html)
Grandtec Tun-5000 (http://www.ezdigitaltv.com/Grandtec_Tun-5000.html)
PHD-205 (http://www.ezdigitaltv.com/PHD-205.html)
Samsung DTBH260F (http://www.ezdigitaltv.com/Samsung_DTBH260F.html)
Samsung SIR-T451 (http://www.ezdigitaltv.com/Samsung_SIR-T451.html)
Sylvania 6900DTE (http://www.ezdigitaltv.com/Sylvania_6900DTE.html)
Tivax STB-T1 (http://www.ezdigitaltv.com/Tivax_STB-T1.html)
Winegard RC-1010 (http://www.ezdigitaltv.com/Winegard_RC-1010.html)

Hi,

I'm totally clueless when it comes to a/v concepts. Can someone explain to me why I can't use a tunerless DVD/VCR to record from an ATSC digital TV? I wasn't able to record with the antenna connected to the VCR, so I connected the antenna to the TV and then RCAs connecting the DVD/VCR to the TV. I got no signal that way either; it recorded black & grey noise.

I'm just totally confused. I don't understand the concept of the signal, where it's coming from, etc. Why doesn't the DVD/VCR pick up the TV's digital signal? If I could understand the concept, I might be less confused.

Thanks,
Bonnie
Perhaps the DVD/VCR wasn't setup correctly to record from "LINE IN"???
Or maybe you forgot to turn the DTV ON during the period of the recording???

Unfortunately, you probably can't "see" the live DTV signal prior to making
a recording because you can't feed the DTV's OTA signal to the DVD/VCR
at the same time as you "view" the DVD/VCR input....

What are TV & DVD/VCR make/model numbers so we can lookup the manuals???
Also let us know if you can't find the manuals...

Yes, the DVD/VCR was set on Line 1. I had both set up according to the Haier (TV) and SONY (DVD/VCR) manuals. DTV was on when I was present, the TV was off when I timer-recorded. It recorded only black & grey noise in both cases. There is no option on the TV for a Line 1, only AV1, AV2 and Component, although I can set it to channel 3. It seems to me that the RF connection between TV and VCR is the critical factor. On my older TVs I can run a coax from TV to DVD/VCR. But there's no RF slot on the Haier, so I'm connecting with the RCAs which seems to be my problem. Does the signal come through only on coax? Is it even possible to VCR-record with a tunerless DVD/VCR and a DTV? That's why I asked about the signal concept - does the DVD/VCR get the signal from the DTV's tuner and on a coax only? Is the RF the issue? Can I put a CECB on the digital TV which seems redundant but may be the only way I can record on this DTV?

There is no option on the TV for a Line 1, only AV1, AV2 and Component

That's the root of your problem. AV1, AV2 and Component are all inputs to the TV. They allow you to feed a signal into the TV from a DVD player, cable or satellite box, or other video source. They do not provide a way to get a signal out of the TV that you can feed into a VCR. Most TVs nowadays have audio outputs that are intended to feed sound to a stereo system so you can get better sound than with the TV's internal speakers; fewer TVs have video outputs of any kind.

Can I put a CECB on the digital TV which seems redundant but may be the only way I can record on this DTV?

You're close. You need to connect the CECB to the VCR so that it can serve as the tuner for the VCR. Your TV already has a tuner, so it doesn't need the CECB for that purpose. I would do it as follows:

1. Put a two-way splitter on the antenna cable. It shouldn't cost more than a few dollars at Radio Shack, Lowe's, or wherever.

2. Connect one output of the splitter directly to the TV's antenna input via coax. This feeds your TV's tuner and allows you to watch TV normally.

3. Connect the other output of the splitter to the CECB's antenna input via coax. Then connect the CECB's audio/video outputs (red, white, and yellow jacks) to matching inputs on the VCR. Finally, connect the VCR's audio/video outputs (red, white and yellow again) to a matching set of inputs on the TV. It sounds like your TV has two sets of these inputs, labeled AV1 and AV2.

To record:

1. Turn on the TV and set it to whichever input (AV1 or AV2) you've connected to the VCR.

2. Turn on the VCR. Since it doesn't have a tuner, it probably assumes the signal is coming in via the audio/video inputs. If it has more than one set of inputs, you'll have to set it to the one that the CECB is connected to, using some button on the remote.

3. Turn on the CECB. You should be able to see whatever it's receiving, on the TV. Set the channel using the CECB's remote. Start and stop recording using the VCR's remote.

Although the CECB's tuner may seem to be redundant, it does give you the ability to record one channel while watching another one. After you start recording one channel on the VCR, you can set the TV to use its own tuner, and use that to tune the other channel and watch it.

If your TV had a video output that you could feed to your VCR, you'd be limited to recording whatever you were actually watching (or could have actually been watching, anyway).

There are a variety of ways to connect CECB, VCR and TV:
http://columbiaisax.googlepages.com/diagram_dtv_tv_vcr.htm
Anywhere you see an RF Coax cable between components, you should add R/W/Y RCA cables,
since CECBs and most VCR's will NOT regenerate Stereo on the RF ouput.

In the above, jtbell recommends an RF Splitter on the antenna coax in order to feed both
the CECB and your DTV so you can watch one channel while recording another.
[RF Splitter not shown in above diagram.]

In fol. diagram, CECB connected to antenna replaces Cable Box:
http://columbiaisav.googlepages.com/vcr_hdtv_connections.htm
The second diagram shows the use of an RF Splitter to feed both the CECB
and the VCR (analog only recordings), which also passes through the RF
signal to the DTV to watch live digital programs.
[jtbell described connecting second port of RF Splitter direct to DTV, bypassing
the VCR, which probably can't receive very many analog stations anymore....]

Sorry, couldn't find a diagram for exactly what jtbell described.....

Whew, I'll need a few readings to digest this info. It reminds me of my math anxiety. Thank you both for the info and time you provided in responding and the helpful Columbia diagrams.

Meanwhile, am I right in understanding that the coax carries the external signal source while the RCAs just improve the quality internally between the TV and VCR?

That's the root of your problem. AV1, AV2 and Component are all inputs to the TV. They allow you to feed a signal into the TV from a DVD player, cable or satellite box, or other video source. They do not provide a way to get a signal out of the TV that you can feed into a VCR. Most TVs nowadays have audio outputs that are intended to feed sound to a stereo system so you can get better sound than with the TV's internal speakers; fewer TVs have video outputs of any kind.
Like I stated above.
When you use RCA cables, the source will be the DVD/VCR. This feeds the television "Baseband" information. The television generally doesn't transmit, except for audio (Red & White jacks), which will usually go to a sound system of some sort.

A "tunerless" device will always need some sort of attached unit like a Cable box, Satellite receiver, or Terrestrial (OTA) receiver (like a CECB).

Whew, I'll need a few readings to digest this info. It reminds me of my math anxiety. Thank you both for the info and time you provided in responding and the helpful Columbia diagrams.

Meanwhile, am I right in understanding that the coax carries the external signal source while the RCAs just improve the quality internally between the TV and VCR?
Correct...also between CECB and VCR....and allows VCR to record Stereo (RCA cables) vice Mono only (Coax cable).

Thanks to you both. I hooked everything up with the box which works fine. Using a splitter sounds interesting, but I don't really need it since I use the bedroom TV/VCR (the one I just hooked up) to record while I'm watching/recording something else in the living room.

I'm sorry if I'm being dense, but is this right: the tunerless VCR can't use the TV's tuner because the TV doesn't transmit the signal?

Bonnie

Correct.

DTV would need OUTPUTS....RF Coax (Ch3/4) and/or RCA Red/White/Yellow (R/L/Video).
[If you had mentioned a model number we could have checked to make sure....]e

It's a CRT: Haier HTR20. It's got one RF and RCAs. So if it had 2 RFs, then I could use the TV tuner to record to VCR? I think my WEGA Trinitron has 2 RFs, but I'm using a CECB on that one, too.

So if it had 2 RFs, then I could use the TV tuner to record to VCR?

Maybe, although I doubt it. I think TV's with two RF (coax) connections use them as separate inputs for antenna and cable TV. A TV with a video output would probably use something besides coax for a better quality signal: either composite (yellow jack), S-video or component-video (three red, green, and blue jacks), plus stereo audio outputs (red and white jacks).

For a newbie, there's just too much information to swallow.

here's my location: http://www.tvfool.com/?option=com_wrapper&Itemid=29&q=id%3d7f14e25e0ffdca

What's the top 3 choices for indoor antenna? what are the techniques to use to get the antenna to get good signal?

Thanks.

Correct.

DTV would need OUTPUTS....RF Coax (Ch3/4) and/or RCA Red/White/Yellow (R/L/Video).
[If you had mentioned a model number we could have checked to make sure....]e
Manual for HTR20 is not available on Haier website, but spec sheet lists a
composite video OUTPUT (presumably R/W/Y RCA plugs x 3):
http://www.haieramerica.com/en/product/HTR20/specs

So you should be able to connect antenna to Haier (via Coax) and connect Haier
to VCR/DVD-Recorder (via R/W/Y RCA cables)....but the Haier will have to be ON
and tuned to the desired channel whenever you schedule a record event,
since connecting Haier to a timer would probably cause it to lose channel memory....

Perhaps you can post a picture of HTR20 connections if you need more info....

PS: There is only ONE RF Coax input for the single ATSC/NTSC/QAM Tuner.

holl_ands,

I noticed in some of your post that you said the Winegard YA-1713 had a 1:1 balun and that it had a high insertion loss. Just curious, have you tried a 1:1 coaxial balun (75Ω balanced to 75Ω unbalanced)?

BTW, I have the Winegard YA-1713 but I am in fairly close proximity to the transmitters of interest so I so not have a signal level problem.

No, the whole kit and kaboodle (YA-1713 plus a Zig-Zag) is in my son's attic waiting for L.A. to switch on Hi-VHF DTV...soon...

I don't know YA-1713's 1:1 Balun insertion loss....it's a ferrite transformer....shouldn't be too bad...UHF is more of a problem.

Thanks to those who replied to my original message, (02/26/09). To recap, the basic problem is bad digital reception at my relatives house about 60 miles outside of Boston.

I decided to go with the CM 7777, and after receiving it and some other parts, finally got a chance to install it the other weekend. The result was the best analog reception I've ever seen there, but only the top 3 channels, (from the TVFool chart), when I switch to digital. So the question is what next?
After spending some time with the antenna, it looks a lot like a CM 3018. Is there much hope that upgrading the antenna to something like the HD8200 would make much difference? Is it safe to assume that as long as you're making a good connection, the age of the antenna doesn't matter? Post transition, the next two target channels are real 7 and 9, so it can't just be a UHF solution. Are there other tips and tricks I can try?
It's frustrating because the analog picture is now very good. I suspect that if I can't get this to work with a somewhat educated effort, there are a lot of other people who's reception is going to go dark this summer.

Analog television is on VHF - the low frequency's.

DTV is in UHF - the high frequency's.

The low frequency's - you used a large antenna - because of the wavelength. UHF - you use a smaller antenna.

You have to remember that the more elements a antenna has, the more gain it has.

The 8200U has more elements than most any other antenna out there.

Your 30+ year old antenna cannot compete with a brand new 8200U

One reason being that the old style antenna used a 300 ohm wire and the 8200 is made to use the 75 ohm wire from the factory.

By just hooking up the 7777 pre amp = you should get a much better signal than with your old antenna, as long as you use a good high quality QUAD SHIELD wire like the Belden 1829 AC..

Analog television is on VHF - the low frequency's.

DTV is in UHF - the high frequency's.



That's not true. There are many DTV stations on VHF and there will be many more after June 12th. In Boston there will be two high band VHF stations WHDH 7 and WMUR 9.

The 8200U recommendation is fine for gain and it does VHF very well. Yet, it will pick up FM stations and FM overload is likely. The HD7698P is smaller and has the same gain as the 8200U on the channels that can be received.

Even then, both VHF and UHF stations from Boston will be hard to receive 100% of the time.

Your 30+ year old antenna cannot compete with a brand new 8200U

One reason being that the old style antenna used a 300 ohm wire and the 8200 is made to use the 75 ohm wire from the factory.


lots of new antennas are to 300 ohm and you use a balun to feed the coax

holl_ands,

I noticed in some of your post that you said the Winegard YA-1713 had a 1:1 balun and that it had a high insertion loss. Just curious, have you tried a 1:1 coaxial balun (75Ω balanced to 75Ω unbalanced)?

BTW, I have the Winegard YA-1713 but I am in fairly close proximity to the transmitters of interest so I so not have a signal level problem.

The impedance of the dipole of an antenna that needs an industry-standard balun is 300 ohms. It is my understanding that in an inductive circuit, the maximum power transfer from source to load takes place when the load impedance is equal to the source impedance. So if you use a so-called 1:1 coaxial balun, and in doing so are placing a 75 ohm load across a 300 ohm source, how much power reduction is incurred due to the impedance mismatch?

BTW, the actual signal loss incurred using an outdoor style, 300 ohm to 75 ohm balun with its two separate wire leads can vary by a couple dB at different frequencies, depending on how the leads are dressed. You will actually do better using an "indoor" balun on an outdoor antenna, since the indoor balun uses twinlead that keeps the two wires optimally spaced.

No mismatch....
And 300-ohm isn't the only "standard" antenna impedance....most LPDAs and Yagi's are 75-ohm.

1:1 Balun is used between a 75-ohm (balanced) antenna and the 75-ohm (unbalanced) coax.
Without it the antenna pattern can be skewed and there will an increase in local noise pickup on the coax.
[The reverse of transmitter signal leakage via an unbalanced load on a Ham radio system.]

4:1 Balun performs a (low loss) impedance transformation between 300-ohm antenna and 75-ohm coax.

The Impedance of a typical wideband TV antenna varies quite a bit vs frequency.
The "Characteristic Impedance" is the "best fit" across the bandwidth.

Folded dipole, Folded dipole Yagis, Bowtie and Gray-Hoverman antennas are usually 300-ohms.
LPDAs (incl. Silver Sensor) and simple dipoles are typically 75-ohms....and should use a 1:1 Balun.
Yagi antennas (e.g. 91XG) tend to be in the 28 to 75-ohm range.

BTW: 4:1 (300 to 75 ohm) and 1:1 (75 to 75-ohm) Baluns may be "standard",
but many other ratios are possible, such as are used in the ClearSteam antennas.

The more complex the antenna is, the more opportunity to "control" the impedance
(or more likely, to lose control, including a propensity to radiate out the BACK).

In YA-1713 Log-Yagi Ken Nist modeled several years ago, he found 300-ohms "best fit".

However, earlier this year I bought a YA-1713 and found significantly different
element sizes, spacings and lengths...clearly the design had changed.
After running 4nec2 sim, I found 75-ohms "best fit" vice 300-ohms.
Careful visual inspection of the Balun revealed that it was indeed 1:1 (vice 4:1):
http://imageevent.com/holl_ands/wgya1713

BTW: Winegard's 1:1 Balun is also used on all HD, CA, CH and CS model antennas.
http://search.solidsignal.com/?q=winegard+terminal+board&I1.x=0&I1.y=0&site=com&new_search=1
The 91XG and most antennas using a unique "Balun Box" are probably NOT 300-ohm....

More 4nec2 sim runs for Yagis, 4-Bays, DBGH, LPDA and Zig-Zag LPA:
http://imageevent.com/holl_ands/yagis
http://imageevent.com/holl_ands/4bay
http://imageevent.com/holl_ands/grayhoverman
http://imageevent.com/holl_ands/zigzaglpa

In a Zig-Zag LPA, impedance blow up must be avoided, the opposite of a Yagi,
with impedance frequently UNDER 75-ohms....

BTW: Winegard's 1:1 Balun is also used on all HD, CA, CH and CS model antennas.When I went to install my Winegard YA-1713 a few years ago it was noted the matching device was housed in a unique enclosure. I just assumed it was not a standard 4:1 balun and they used that enclosure to keep folks from using a 300Ω to 75Ω balun.

BTW, good summary on antenna types.

Belden 1829A/AC has their DuoBond II shield (foil/braid), which is not quad shield. Their quad shield is called DuoBond IV. The 1829A takes a standard sized F56 connector and is highly recommended for satellite, cable and antenna distribution.

It was mentioned that baluns with separate wire leads may have their performance degraded by the way the wire leads are dressed. That one is easy to avoid, use one of the models shown below. They have standard 300Ω twin lead wire on the input (or output) side.

Winegard TV-2900 Weatherproof Transformer, info here (http://www.winegard.com/offair/couplers.php)

MCM 33-040 Weather ResistantTransformer, info here (http://www.mcmelectronics.com/product/33-040)


It is not a concern for me as my Winegard YA-1713 has a cartridge style 1:1 balun and I use a λ/2 coaxial cable balun on my Winegard PR-9032.

http://farm4.static.flickr.com/3312/3639689317_8172d424bc_o.png

When I went to install my Winegard YA-1713 a few years ago it was noted the matching device was housed in a unique enclosure. I just assumed it was not a standard 4:1 balun and they used that enclosure to keep folks from using a 300Ω to 75Ω balun...

I thinnk they do that just for weatherization. Both Channel Master and Winegard used "gas tight" coupling to the busses. The housings used to be over twice as tall as the Winegard housing is now, and an installer could choose from among several amplifying and non-amplifying terminal boards. I'm quite sure that there was a 300 ohm terminal board with the penetrating "tooth washers" for those who were still partial to using twinlead. In fact, I think the non-amplifier boards had both 300 ohm and 75 ohm output terminals, but I don't remember if we had to sever the output circuit that we were not using.

That coupling design proved to be very inconvenient to the installer/service person, since he would have to carry separate amplifier and terminal modules for each brand of antenna. Now, Winegard has just two, 75 ohm output coupling boards: A VHF only and a UHF/VHF, which has a VHF coupling F-71 port as well.

Winegard shows four models of cartridge housed baluns, one model is for older antennas. Info here (http://www.winegarddirect.com/viewitem.asp?d=Winegard-CB-2130-CAHD-VHF-Terminal-Board-2120551-(CB2130)&p=CB-2130). The connections from the terminal board to the phasing lines is just a friction fit and it is not “gas tight”. These cartridges are 1:1, 75Ω baluns. Do not connect 300Ω devices (4:1 baluns, 300Ω twin lead, etc.) to the phasing lines, you will have degraded performance. The output of the phasing line is 75Ω balanced.

I have a HBU-22 antenna which is working pretty well except for when there's rough weather between me and the transmitters. Also have 2 stations that are in a different direction from the rest - WFUM and WADL - that are more prone to breakup (but still OK 80% of the time). I'm splitting the signal to a second TV which seems to have more issues. (and a 150' run) I'd also like to get CBET when (and if) Canada goes digital.

Can anyone recommend a preamp? tvfool is attached.

i have a hbu-22 antenna which is working pretty well except for when there's rough weather between me and the transmitters. Also have 2 stations that are in a different direction from the rest - wfum and wadl - that are more prone to breakup (but still ok 80% of the time). I'm splitting the signal to a second tv which seems to have more issues. (and a 150' run) i'd also like to get cbet when (and if) canada goes digital.

Can anyone recommend a preamp? Tvfool is attached.

hdp-269

I second TGs recommendation.

Sorry to disagree, but I think that a Winegard AP 8275 would be a better choice.

Sorry to disagree, but I think that a Winegard AP 8275 would be a better choice.
Now I'm really confused. I was looking at the AP8700 vs the AP8275, but I wasnt sure if the 8275 was too much. The HDP-269 is even lower gain than the 8700. Is the HDP somehow better than the AP line?

The 8275 is too much pre-amp for you. It is too susceptible to overload, and you don't need a high gain deep fringe amp. The 8700 is much less susceptible to overload, but you don't that much gain either if you already get decent reception most of the time. The HDP-269 with 12db of gain is more than enough gain for 2 TV's, and nearly impossible to overload.

I installed the 8275 at the location below last weekend, and it works great with a small Winegard Ghost Killer antenna. I wouldn't use the 8275 with signal strengths higher than these.

http://www.tvfool.com/?option=com_wrapper&Itemid=29&q=id%3dc5347d02d523de

Is it possible to replace a rotor control unit without needing to replace the rotor itself on the antenna?

I got my parents set up for the DTV conversion with a CECB and things seemed good. Later went to do a little fine tuning and when adjusting the antenna, the control unit started making a grinding noise and the antenna did not stop at the desired setting. I reversed the direction and pulled the plug when the antenna got mostly pointed correctly. It's an old (maybe 20+ years) rotor control unit and I suspect some of the plastic gears inside might have cracked or finally worn out. When asking around my dad was told that the control unit inside the house and the drive unit on the antenna would need to be replaced together as a unit.

True or not?

I don't remember the rotor control brand but it wasn't something familiar so finding the same brand may not be possible. Otherwise I believe it's a Winegard antenna solely based based on the (W) I can see on it and a CM amp.

Thanks

Hello All -
I want to put up a VHF-Hi and UHF antenna now that the transition is complete (Channels 7, 9, and 11 went back to VHF-Hi in my area (DC-Balt).

This is a general question about antennas and masts...

When the OTARD rule says HOA may not limit erection of an antenna, and that local codes may limit to 12' above roof does that mean:

- 12' is the highest tip of the antenna or can the antenna be a foot or two higher if it installs on top of a 12' mast?

- Does the chimney come into play for the height above roof? My chimney is higher than the peak of the roof. I'm down a hill, so every foot of height helps. However, I also have to be by the book because I am already sure this is going to raise the ire of the HOA.

- Diagrams I've seen show the antenna at the side of the house, I'm guessing that helps with multipath reflections off the asphalt shingles? Is the side the preferred location or, if you get better signal somewhere along the peak of the roof, is there a mast that bolts to the roof away from the edges?

Thanks for any help!

Hello All -
I want to put up a VHF-Hi and UHF antenna now that the transition is complete (Channels 7, 9, and 11 went back to VHF-Hi in my area (DC-Balt).

This is a general question about antennas and masts...

When the OTARD rule says HOA may not limit erection of an antenna, and that local codes may limit to 12' above roof does that mean:

- 12' is the highest tip of the antenna or can the antenna be a foot or two higher if it installs on top of a 12' mast?

- Does the chimney come into play for the height above roof? My chimney is higher than the peak of the roof. I'm down a hill, so every foot of height helps. However, I also have to be by the book because I am already sure this is going to raise the ire of the HOA.

- Diagrams I've seen show the antenna at the side of the house, I'm guessing that helps with multipath reflections off the asphalt shingles? Is the side the preferred location or, if you get better signal somewhere along the peak of the roof, is there a mast that bolts to the roof away from the edges?

Thanks for any help!

The FCC rule says that "Masts higher than 12 feet above the roofline may be subject to local permitting requirements.". This would be a matter of your local building or code enforcement office, not an HOA. Check with your local AHJ (if any) to see if such a permitting requirement exists in your city or county.

If there is no such local restriction, your other question regarding the chimney is moot.

The preferred location is the one where you can get a good quality signal with the minimum amount of difficulties.

Is it possible to replace a rotor control unit without needing to replace the rotor itself on the antenna?

I got my parents set up for the DTV conversion with a CECB and things seemed good. Later went to do a little fine tuning and when adjusting the antenna, the control unit started making a grinding noise and the antenna did not stop at the desired setting. I reversed the direction and pulled the plug when the antenna got mostly pointed correctly. It's an old (maybe 20+ years) rotor control unit and I suspect some of the plastic gears inside might have cracked or finally worn out. When asking around my dad was told that the control unit inside the house and the drive unit on the antenna would need to be replaced together as a unit.

True or not?

I don't remember the rotor control brand but it wasn't something familiar so finding the same brand may not be possible. Otherwise I believe it's a Winegard antenna solely based based on the (W) I can see on it and a CM amp.

Thanks
The Channel Master's are independent. I replaced my motor unit and kept my infra-red remote-controlled CM controller.

In your case, it's hard to tell if your rotor and controller are independent. You really need to find out what brand and model you have.

Is it possible to replace a rotor control unit without needing to replace the rotor itself on the antenna?

I got my parents set up for the DTV conversion with a CECB and things seemed good. Later went to do a little fine tuning and when adjusting the antenna, the control unit started making a grinding noise and the antenna did not stop at the desired setting. I reversed the direction and pulled the plug when the antenna got mostly pointed correctly. It's an old (maybe 20+ years) rotor control unit and I suspect some of the plastic gears inside might have cracked or finally worn out. When asking around my dad was told that the control unit inside the house and the drive unit on the antenna would need to be replaced together as a unit.

True or not?

I don't remember the rotor control brand but it wasn't something familiar so finding the same brand may not be possible. Otherwise I believe it's a Winegard antenna solely based based on the (W) I can see on it and a CM amp.

Thanks

Can you post a picture of the rotor or control, might be able to tell from that. I have some old catalogs for several different rotors.

Can you post a picture of the rotor or control, might be able to tell from that. I have some old catalogs for several different rotors.

Thanks for the offer. I can't do anything till I get a chance to get back to my parents house. I walked them through rescans & configuration over the phone this weekend and they seem to be getting most of the channels post conversion so it's not as critical as I had anticipated.

The 8275 is too much pre-amp for you. It is too susceptible to overload, and you don't need a high gain deep fringe amp. The 8700 is much less susceptible to overload, but you don't that much gain either if you already get decent reception most of the time. The HDP-269 with 12db of gain is more than enough gain for 2 TV's, and nearly impossible to overload.

I installed the 8275 at the location below last weekend, and it works great with a small Winegard Ghost Killer antenna. I wouldn't use the 8275 with signal strengths higher than these.

http://www.tvfool.com/?option=com_wrapper&Itemid=29&q=id%3dc5347d02d523de

Based on what you're saying it sounds like HDP-269 would work for me as well.

http://www.tvfool.com/?option=com_wrapper&Itemid=29&q=id%3dc534a39f416434
Note: Since I live in Boulder the Rocky Mountains are practically in the front yard and the curve of the mountains keeps me from having a true line of sight to Lookout Mountain where most of the Denver area tv transmitters are located, i.e. there's a very big rock between Boulder and Golden.

The only channels I'm concerned about receiving are
2.1, 4.1, 6.1, 7.1, 9.1, 12.1, 20.1, 31.1, - 59.1 and 38.1 occasionally run movies or programs of interest. I receive a number of others but remove them from the channel lineup. 12.1 I may not be able to get till mid to late this year when they finish their translator/retransmit construction for north Denver metro. 6.1 I get from a translator mounted on the residence halls at CU about 2 miles away.



My signal reception for the channels I receive is measuring from the high 60's to the mid 80's on my DTVPal. Middling to the lower edge of good on the DTT901. So some signal boost all around wouldn't go amiss.

I am experiencing occasional weather related dropouts on the channels. I can see some signal for 2.1, 31.1 and 12.1 on the DTT901 but not enough to get a picture (not even a choppy pixelated freeze up). The setup came with the house and is bit funky. Roof mounted antenna, outdoor transformer (300 to 75 ohm) to attach antenna to 30 feet or so of coax that runs into the floor level of the house (1 level ranch). A second flat cable is attached to the antenna that runs to the basement. My thought was to install the pre amp, then a splitter (with a voltage block on the basement cable) at the antenna, with the power injector on the main floor before the distribution amp (maybe that the distribution amp gets replaced with a 4way splitter after this).



So if I understand this page (http://www.dennysantennaservice.com/1136577.html) right I'd lose 3.7db on the splitter, ~1.5db on the coax, and what about .5db on the outdoor transformer?
5.7 DB so a pre amp in the 10-15 db range would do. Voila - the HDP-269.

Do any of the national chain type stores sell the 269 in their physical stores? Radio Shack seems to only offer the 8700 online and the 269 not at all. I'd like to buy one that I could return without shipping it, if needed.

Anyone know where I can get bulk quantities of the Channel Master 3072's and 3075's?

Anyone know where I can get bulk quantities of the Channel Master 3072's and 3075's?I would contact Channel Master here (http://www.channelmaster.com/contactus.php) and inquire about one of their distributors.

I am located in Winlock WA, and have been receiving OTA UHF digital signals for a couple years. I'm using stacked 91 XG's, about 40' off the ground on a rotor. I have a Channel master pre-amp with seperate leades for VHF and UHF, but threw away my channelmaster 3671 vhf combo antenna a couple months ago as the VHF analog didn't compare to the digital UHF, so we never watched any of the channels. I was only using it for VHF as the UHF reception on it did not cmpare to a single 91XG. Three of the stations we watch went back to VHF after the transition, 8,10 and 12. I bought a Antenna craft Y10-7-13 and put it up Friday, signal is marginal on 10 and 8, while 12 doesn't pick up at all. Is there a better VHF hi-band available? If not is there a combo antenna that is as good on UHF as my 91XG's, if so I could reluctantly replace both of them with two combo antennas? I am about 75 miles from the transmitters. Thanks.

I keep reading that the Wade-Delhi VIP 306 and 307 are the best; they are huge understand but supposed to be the best for long distance.

I am located in Winlock WA, and have been receiving OTA UHF digital signals for a couple years. I'm using stacked 91 XG's, about 40' off the ground on a rotor. I have a Channel master pre-amp with seperate leades for VHF and UHF, but threw away my channelmaster 3671 vhf combo antenna a couple months ago as the VHF analog didn't compare to the digital UHF, so we never watched any of the channels. I was only using it for VHF as the UHF reception on it did not cmpare to a single 91XG. Three of the stations we watch went back to VHF after the transition, 8,10 and 12. I bought a Antenna craft Y10-7-13 and put it up Friday, signal is marginal on 10 and 8, while 12 doesn't pick up at all. Is there a better VHF hi-band available? If not is there a combo antenna that is as good on UHF as my 91XG's, if so I could reluctantly replace both of them with two combo antennas? I am about 75 miles from the transmitters. Thanks.

A Funke psp1922 would be an option if you can find one. MaxHD used to have some for sale here at AVS. It's the top antenna in the first pic below.

You could also stack two Y10 7-13's either vertically or horizontally.

Be sure your receiver is picking up the correct actual channel for 12. Post transition there are some PSIP issues causing "loss" of a channel. You may need to rescan or even erase the channels entirely and start over.

You won't find a combo antenna as good for uhf as a dedicated uhf antenna.

Is there a better VHF hi-band available? If not is there a combo antenna that is as good on UHF as my 91XG's, if so I could reluctantly replace both of them with two combo antennas? I am about 75 miles from the transmitters. Thanks.The best 7-69 combo antenna is the Winegard HD7698P. It offers more VHF gain than the Y10-7-13, but it's UHF performance is about 10% less than the 91-XG.

I bought a Antenna craft Y10-7-13 and put it up Friday, signal is marginal on 10 and 8, while 12 doesn't pick up at all. Is there a better VHF hi-band available? If not is there a combo antenna that is as good on UHF as my 91XG's, if so I could reluctantly replace both of them with two combo antennas? I am about 75 miles from the transmitters.The Winegard YA-1713 has more gain than the Antennacraft Y10-7-13. Would it actually perform any better in your situation would be guess work and unfortunately, there is only one way to know for sure.

The following is for “average terrain”, if your transmit antenna is at 1500' level then the receive antenna would need to be at 205' level for line of sight at 75 miles.

This is my first post, and I am a little confused about how the forum works. I want to post a query, but I can't find out how to do that, so I am trying to post a reply, although I don't know who I am replying to. I just spent the last hour composing my "reply", and when I tried to send it, it disappeared. Is there a time limit?

Anyway, I will break my questions into separate posts. My first question is, how do I know if my antenna/amp system is causing overload. It consists of two antennas connected to a CM7777 preamp which, in turn, is connected to a RS 4-way amplified splitter. Removing the splitter seems to have no effect. The maximum signal strength I get is 40%.

Post your TVfool and what antennas you are using with the CM 7777, how long the cabling, and where your antenna(s) are located.

Also what is your house made of and roofing material?

For UHF, I am usiing a CM 4248 Yagi, for VHF, I am using a dipole cut to channel 13. Both are located in my attic pointing to the west through a window.. The ESB is 254 degrees, and WLIW-21 is 239 degrees. The CM777 is mounted on the mast, with about 4 feet of RG6 to the UHF terminals of the 4248, the dipole is mounted on the window frame with about 6 feet of 300 twin lead, and the cable from the 7777 to the TV is about 20 feet long, also RG6. This is a test setup installed in the winter to see if it works; I plan to put it on the roof after this proof-of-concept.

The house is a frame house with an asphalt roof, but the signals don't come in through the roof.

I can give a lot more information, but I don't want to lose the post as I did last time.

http://sbmp95.ess.sunysb.edu/Radar-Digital2.png

And what are you not getting? What are you trying to get?



Here is what I would do.

Make a DIY GrayHoverman with the additional VHF High augmentation that 300ohm can tell you about in the How to Build a UHF Antenna thread. Dont add a reflector because you want it bi-directional so you can get the 268 and 30 degree magnetic compass heading transmissions (finding a nuanced postion off axis from both just East of 30 degrees and just South of 268 degrees to aim the antenna).

I would keep the CM7777 as it will likely have a lower noise figure than the Distribution Amp, and get rid of the distribution amplifier and go with a 4 way splitter of good quality (or whatever number of lines you need).

This will get you most of the stations at 268 and 30 degrees magnetic.


The Gray Hoverman with VHF High augmentation has great bandwidth and beamwidth and good gain figures.

The Winegard YA-1713 has more gain than the Antennacraft Y10-7-13. Would it actually perform any better in your situation would be guess work and unfortunately, there is only one way to know for sure.

The following is for “average terrain”, if your transmit antenna is at 1500' level then the receive antenna would need to be at 205' level for line of sight at 75 miles.
I had the winegaurd on order for over a week but cancelled as the shipment to Solid Signal kept getting delayed. I thought the antennacraft would do the job, that's what I get for thinking. Now I'm considering loosing one of the 91XG's and trying the antennacraft further up the mast where the lower 91XG was, or one of these other antennas recomended if I can find one. Originaly I had only 1 91XG aprox 29' off the ground for UHF and got most of the stations I receive now. When I added the second 91XG I re-masted and incresed height to over 42' off the ground, so I was never sure if all the gain was from the second antenna or the height increase. My house is on a hill approx 450' above sea level and when I put up the Antennacraft y10 7-13 on friday it was only 30' off the ground. Any thoughts?

Make sure you mount the VHF-Hi antenna at least 32" below the UHF antennas and 32" above roof line.

Are you on a tower or are you mounting a pipe on the roof?

If you point the antenna to 268°M, I would think that you should not have any problem acquiring 7, 8, 11, or 13 (maybe even 12).

Any thoughts?I assume you are trying for the Seattle/Tacoma stations. There is a pretty good range of hills between you and the transmitter antennas. Click here (http://maps.google.com/) for Goggle maps, enter your City, ST click Search, then click Terrain for topographic map. 75 miles is considered deep fringe. The heights that I posted is the height needed just to clear the earths surface because of the earths curvature. If you are open to experimenting, the first thing I would try is to see what kind of VHF reception I could get. I would put up only the VHF antenna as high as possible and no pre-amp.

Keep in mind antenna spacing when you use a separate VHF and UHF antenna.

I would keep the CM7777 as it will likely have a lower noise figure than the Distribution Amp, and get rid of the distribution amplifier and go with a 4 way.A 7777 with signal strengths like that?????????? There is no way it will work. The 7777 is designed for the boonies.

His transmitters at 254 (and 253) degrees go all the way down into the red, and he is trying to pick up channels at 10 degrees as well. Bidirectional antenna (with therefore less gain), the amp will help tremendously, and he also has a 4 way splitter (12db down) and cable runs to overcome.

I dont see a problem. This will maximize his channels in a set and forget solution. No?

Alternatively he could get rid of the CM 7777 and keep the Distro Amp, but I find that an inferior solution, (unless he gets some overloading which I dont anticipate). After the 4way split that is +6db per cable to combat cable losses on UHF (lets assume -3db average on each cable run). Doesnt seem to be a problem to me. Add to that -3db for the attic/roof attenuation. And a 8-10db Gray Hoverman gain...apply all that to -70dbm signal strength on average.....attic attenuates the strongest stations at -40dm. I only forsee a possible problem on Channel 23 Telemundo, but even if that overloads the tuner on that one channel, youve still got 2 Telemundos to watch, and youve gained yourself some stability and extra channels on the low signal strength stuff down the list into the red.

Am I wrong?

The strongest stations are more imporatant that the weaker ones when deciding on a pre-amp. The slightest amount of overload at the pre-amp "input" will lessen the chances of seeing the desired weaker channels. The Winegard 2870 would be the highest gain unit I would even consider. To be on the safe side I would go with the HDP-269 since the antenna is coming out of the attic eventually.

I had the winegaurd on order for over a week but cancelled as the shipment to Solid Signal kept getting delayed. I thought the antennacraft would do the job, that's what I get for thinking. Now I'm considering loosing one of the 91XG's and trying the antennacraft further up the mast where the lower 91XG was, or one of these other antennas recomended if I can find one. Originaly I had only 1 91XG aprox 29' off the ground for UHF and got most of the stations I receive now. When I added the second 91XG I re-masted and incresed height to over 42' off the ground, so I was never sure if all the gain was from the second antenna or the height increase. My house is on a hill approx 450' above sea level and when I put up the Antennacraft y10 7-13 on friday it was only 30' off the ground. Any thoughts?

There's won't likely be any performance difference b/w the Antennacraft Y10 and the Winegard Y10. Winegard is known for inflating their gain figures.

Experimenting with position on the mast is certainly a good idea. Higher may not always be better.

As far as long range antennas go for hi band vhf, to get noticeably "better" you'll need the huge Delhi, the relatively huge psp1922, or a stack of Y10's.

Winegard is known for inflating their gain figures.Really. Can you provide some scientific data to backup such a statement. I am not interested in “they said, he said” statements.

His transmitters at 254 (and 253) degrees go all the way down into the red, and he is trying to pick up channels at 10 degrees as well. Bidirectional antenna (with therefore less gain), the amp will help tremendously.

Am I wrong?

Yes.

I think that trying to receive red color stations with a bidirectional antenna won't work.

The strongest stations are more imporatant that the weaker ones when deciding on a pre-amp. The slightest amount of overload at the pre-amp "input" will lessen the chances of seeing the desired weaker channels. The Winegard 2870 would be the highest gain unit I would even consider. To be on the safe side I would go with the HDP-269 since the antenna is coming out of the attic eventually.

45 miles from the towers is the boonies.

I have a CM7777 hoooked up to a CM4221 and 50ft of RG6....most stations at -70dbm one at -40dbm, no problems here.

But I understand your assertion. Perhaps the 269 is the way to go, but he has in his possession a CM7777 and a RS 4 way distro amp. Of those 2, Id try the CM7777 first, by itself.

Really. Can you provide some scientific data to backup such a statement. I am not interested in “they said, he said” statements.

Just anectodal and from my experience. No offense meant.

The PR9032 doesn't perform as well as it should based on its published gain specs for uhf and neither does the 8200p for vhf.

The PR9032 doesn't perform as well as it should based on its published gain specs for uhf . . . . . Do you feel the 91-XG is substantially better?

Thanks!!

Just anectodal and from my experience. No offense meant.None taken!

The PR9032 doesn't perform as well as it should based on its published gain specs for uhf and neither does the 8200p for vhf.Click here (http://www.avsforum.com/avs-vb/attachment.php?attachmentid=43178&d=1127600571) for antenna test done by Bob Chase. Please note the last two pages cover the UHF band. Also note there is not that much difference between antennas of similar design. Bob did not test the Winegard PR-9032 but he did test the Channel Master 4248. It was one of the best UHF models, the PR-9032 is of similar design and should meet or exceed the 4248 in performance. Some people were having trouble because they did not read the instructions for the PR-9032 and were making down-lead connections to the VHF “pass-thru” connection point (some did this to the CM-4248).

Click here (http://www.avsforum.com/avs-vb/showthread.php?p=16737863#post16737863) for my install and flow chart.

First, I want to thank Escape Velocity, Systems2000, Digital Rules, and Tower Guy for addressing my reception problem. I already was concerned with Digital Rules' issue about my having too much gain. I assume that I can calculate the signal strength, so I shall do that now for the two stations which concern me most: WLIW Channel 21, 20 miles at 239 degrees (my strongest station), and WNJN Channel 51, 55 miles at 266 degrees. My CM 4248 28 element Yagi has a UHF gain of 10.8 dB. The 7777 preamp has a UHF gain of 26 dB, with a noise figure of 2.0 dB; UHF output capacity is 51 dBmV.

I don't exactly know what to do with those numbers, but if I add the two gains together (10.8 + 26 = 38.8), and add them to the PWR figure for the two stations, I get -10.1 dB for channel 21 and -31.9 dB for channel 51, which both seem awfully low. The antenna gains are relative to a reference dipole, but how much signal voltage does a power of -48.9 dB generate in such a reference dipole? Is 21.8 dB too great a difference to pick up both stations without overloading? Is the overload problem a function of the strongest station, even if I am tuned to a different station? If we are talking about preamp overload, then I assume the answer is yes, because the preamp is untuned. If it is the TV tuner's overload, then I don't know; probably still yes, because I don't think the input stage of the ATSC tuner is tuned.

When I put up my original-but-now-defunct Radio Shack antenna on my roof in 1990, I could get both 21 and 50 (analog, of course). Just prior to 6/12, I could get analog 50 (weakly) with my attic-mounted 4248.

A problem with Escape Velocity's suggestion to pick up the CT stations off the back because both directions have channel 31 (WTIC at NM of 19.9, and WPXN at NM of 16.1).

The table below lists all the stations I should receive, based on TVfool (info except quality from TVfool).

Call chnl virtual NM(dB) Pwr Azimuth Quality Antenna
"GREEN"
WFTY-DT 23 (67.X) 67.1 -28.2 105 POOR unamplified Silver Sensor pointing @~20 degrees
WSAH-DT 42 (43.X) 50.0 -40.8 3 POOR unamplified Silver Sensor pointing @~20 degrees
WLNY-DT 47 (55?) 48.9 -41.9 100 POOR unamplified Silver Sensor pointing @~20 degrees
WLIW-DT 21 (21.X) 41.9 -48.9 239 GOOD either (or both)
WCTX-DT 39 (59.X) 39.9 -50.9 16 POOR unamplified Silver Sensor pointing @~20 degrees
WTNH-DT 10 (8.X) 38.4 -52.5 16 FAIR unamplified Silver Sensor pointing @~20 degrees (should try a VHF antenna here)
WEDW-DT 49 (49.X) 37.2 -53.6 355 GOOD unamplified Silver Sensor pointing @~20 degrees

"YELLOW"
WABC-DT 7 (7.X) 27.1 -63.7 254 GOOD amplified channel 13 dipole pointing @~220 degrees
WEDY-DT 6 (65.X) 25.8 -65.0 24 NONE neither
WNJU-DT 36 (47.X) 25.7 -65.1 254 POOR amplified CM4248 pointing @~220 degrees
WVIT-DT 35 (30.X) 25.5 -65.3 17 POOR unamplified Silver Sensor pointing @ ~20 degrees
WTXX-DT 20 (61.x?) 25.0 -65.9 17 POOR unamplified Silver Sensor pointing @ ~20 degrees
WNJB-DT 8 (58.1) 23.8 -67.0 255 NONE neither
WNET-DT 13 (13.X) 23.7 -67.1 254 GOOD amplified channel 13 dipole pointing @~220 degrees
WPIX-DT 11 (11.X) 23.6 -67.3 254 VERY POOR OR NONE
WNYW-DT 44 (5.X) 23.1 -67.7 254 NONE neither
WKOB-LP 2 (42.1) 21.7 -69.1 254 NONE neither
WCBS-DT 33 (2.X) 21.2 -69.7 254 NONE (got it once before 6/12)
WMBC-DT 18 (63.1) 20.7 -70.2 266 NONE neither
WNBC-DT 28 (4.X) 20.3 -70.5 254 NONE neither
WXTV-DT 40 (41.X) 20.2 -70.6 254 FAIR amplified CM4248 pointing @~220 degrees
WTIC-DT 31 (61.X) 19.9 -70.9 17 POOR unamplified Silver Sensor pointing @ ~20 degrees
WEDH-DT 45 (24.X?) 18.9 -71.9 17 VERY POOR unamplified Silver Sensor pointing @ ~20 degrees
WWOR-DT 38 (9.X) 18.3 -72.6 254 NONE neither
WNYE-DT 24 (25.1) 18.2 -72.7 255 POOR amplified CM4248 pointing @~220 degrees
WTBY-DT 27 (54.X) 17.9 -72.9 313 GOOD amplified CM4248 pointing @~220 degrees
WFUT-DT 30 (68.x) 16.7 -74.2 254 VERY POOR amplified CM4248 pointing @~220 degrees
WFSB-DT 33 (3.X) 16.4 -74.4 17 NONE neither
WPXN-DT 31 (31.X) 16.1 -74.7 254 NONE neither
WRNN-DT 48 (48.X?) 12.9 -77.9 313 NONE neither
WNJN-DT 51 (50.X) 12.9 -77.9 266 NONE (used to get analog)

Nothing weaker than this.

Sorry this table is poorly formatted - I used Notepad with tabs to create it. It does, however, bring up a few questions:
According to TVfool FAQs, all of these noise margins are plenty high to get all the signals umamplified, but I don't.
Why do I get a good signal on WEDW-49 and not on WSAH-42? Both are to the north, LOS, and WSAH is stronger!
WNET-13 and WPIX-11 are almost adjacent channels and both on the Empire State Building (I think), but I usually can't get 11.

I am using a CM selector switch to connect the two antenna systems. I tried a passive splitter as a combiner, but most stations disappeared, although, if I scanned my tuner with this setup, both sets of stations appeared!

The cable between the Silver Sensor and the switch is a new RG6, about 20 feet long. THe cable between the 7777 and the switch is an old RG59 inside the wall, and is also about 20 feet long - should I replace it?

All this stuff is in my 3rd floor attic, including all antennas, the Samsung TV, a Panasonic ATSC DVD recorder, and a CM7000 converter box. In addition, I have a 30 foot RG59 going to my second floor computer room, to an ATI tuner card. I also have an RG50 cable running underground to an apartment in my garage, probably 150 feet long. All the extra cables are not now being used, but that is why I had the amplified RS splitter.

Yes.

I think that trying to receive red color stations with a bidirectional antenna won't work.

What is the gain figure on the Gray Hoverman without a reflector?

I understand the difficulty. The point is to try to get as deep into yellow as possible from both directions....to maximize the number of channels and stabilize them.


Any other suggestions for MTVike? Should he do an A/B setup or forget one direction?

Why do I get a good signal on WEDW-49 and not on WSAH-42? Both are to the north, LOS, and WSAH is stronger!
WNET-13 and WPIX-11 are almost adjacent channels and both on the Empire State Building (I think), but I usually can't get 11.
I've been finding that how we think about signal strength for DTV is not the same as it was for NTSC. Many OTA viewers are finding that high signal strength isn't giving them reception. Try placing different size anttenuators in your cable line.

I've found that, depending upon where you place the attenuator, it makes a marked difference on DTV capabilities. I'm using a CM0265DSB pre-amp and a 25dB DA with splitters throughout the house distribution system. I have attenuators before the DA, before splitters, and after splitters.

It's an on-going experiment to find the right balance.

Do you feel the 91-XG is substantially better?

Thanks!!

I've never had an xg91. I can tell you that from my experience the Televes DAT75 is easily better up and down the uhf band as is the CM4228 (both compared to the pr9032).

The published specs on the pr9032 claim comparable gain to the Triax Unix 100A (a band-specific antenna for uhf 14-38) for channels 14 and 32. I own and have extensively tested both and can confidently say they aren't even close.

http://www.winegard.com/kbase/upload/Pr-9032.pdf
http://www.njal.no/Doc/Triax%20produktinfo%20antenne%20100element.pdf

For the 100A gain chart, the trace at the left is for the A band model. Channel 21 on the graph is equivalent to channel 14 in the US.

What is the gain figure on the Gray Hoverman without a reflector?

I understand the difficulty. The point is to try to get as deep into yellow as possible from both directions....to maximize the number of channels and stabilize them.


Any other suggestions for MTVike? Should he do an A/B setup or forget one direction?

My suggestion for MTVike is to establish a reception baseline with a single antenna aimed in one direction at a time with no preamp to verify signal strength and antenna location. Next I'd add a low gain preamp to make sure that doesn't overload. Check stations in all directions. Once its known what can be received and what can't then its time to try tricks to combine two antennas.

In most cases red zone antenna combining must be done with filters such as Jointennas, UVSJs, and HLSJs.

Sound advice.

Good Luck MTVmike!

I am trying to pick up Portland, I do have a Rotor, but I pick up alot more from Portland than seattle. I started with a 3671 for VHF, as that is what I had used my previous homes in the area, but was disapointed in the results. The UHF only went fine until my 2 year old daughter's favorite station disapeard when OPB 10 went back to VHF. I have a 5' tripod on the peak of my roof, 11' of mast conected to a rotor and another 11' mast. The two mast's overlap approx 18" and I have a thrust bearing at the top, I don't have enough room above the rotor for a 3rd antenna. I have thought about a tower, but I am already over 40' off the ground. TV FOOL and photo of my antennas attached. I took the Y10 7-13 down, I tried it within a 25' radius of my UHF set up, up to 9' off the peak. Signal was marginal at best for 8 and 10while 12 didnt show up at all. I am still getting 2.1,2.2,6.1,13.1,13.2,15.1,15.2,15.3,15.4,22.1,22.2,22.3,32. 1,32.2, and 49.1 all the time without issue. 13.1 is tacoma wa, 15.1 has a repeater in Centalia WA, the rest is Portland. Thanks for the help, I'm still not sure what to try next. I'm afraid id I go to one 91XG I will loose some of the UHF I already get.

I'm still not sure what to try next. I'm afraid id I go to one 91XG I will loose some of the UHF I already get.Are you ampifying the VHF antenna along with the 91-XG's? I see you have 6 analog & digital LOS UHF stations very closeby. I would try the YA-1713 unamplified, or run it on it's own independent amp and see what you get.

Are you ampifying the VHF antenna along with the 91-XG's? I see you have 6 analog & digital LOS UHF stations very closeby. I would try the YA-1713 unamplified, or run it on it's own independent amp and see what you get.
Yes I am using a Chanelmaster 7777 pre-amp with sperate vhf/uhf leads. My understanding on this pre-amp was the two were completley seperat aslong as I have the switch se to seperat rather than combined? I tried a CM3671 antenna without the pre-amp for VHF analog about a year ago, with poor results. The only close by LOS station I have ever goten 19 (15.1-15.4). I have never been able to get the others. I even tried using both the CM3671 combo and one 91XG without an amp for uhf, and the 6.1 mile stations just dont come in, at all. If you still think I should try the Y10 without an amp, I will. Thanks.

Although Ive been drubbed by conventional wisdom purveryors here, Pete Putman the HDTVexpert, doesnt seem daunted about using his CM 7777 amplifier....at stations 20 miles away with medium gain antennas. In fact from this and other test on indoor antennas that he has done in the past, it seems to indicate that the CM7777 in fact is helping much more than hurting reception....with nice 8VSB waveforms I might add. In fact in this particular article, the CM7777 makes the Winegard 269 look bad.

Five (Antennas) To Get Ready

PETER PUTMAN, CTS

http://www.hdtvexpert.com/pages_c/Five_Antennas.html

Specifically this chart....in which all antennas are amped with the CM7777 or have no amplifier....except for the Winegard SS2000 which is a SS1000 with a Winegard 269 amplifier....allowing for direct comparison. Additionally, look at the figures for the other antennas which all bring in many more channels with good clean signals than unamped.

Call me a uppity newbie, but Ill stick with my recommendation.

http://www.hdtvexpert.com/images_c/5antennas_2.gif

If you still think I should try the Y10 without an amp, I will. Thanks.I would certainly try it. In the analog days, I remember strong UHF stations causing herringbone patterns on some weak VHF channels when I amplified them together. With separate amps for each antenna, the problem went away.

I would certainly try it. In the analog days, I remember strong UHF stations causing herringbone patterns on some weak VHF channels when I amplified them together. With separate amps for each antenna, the problem went away.
At this point I have nothing to loose, it's just one more trip on the roof. I'll let you know, thanks.

Although Ive been drubbed by conventional wisdom purveryors here, Pete Putman the HDTVexpert, doesnt seem daunted about using his CM 7777 amplifier....at stations 20 miles away with medium gain antennas.

He's in the Allentown, PA area and the antennas aren't all that high, meaning he's probably receiving most of those stations via diffraction.

On the other hand, I'm 16 miles from Roxborough with fewer hills, and am also getting good results with a CM7777. I needed it before the transition to receive WHYY's squirrel-powered signal reliably, but it's still there and working fine. So yeah, I think the CM7777s capacity for handling high signal strengths is underrated.

Although Ive been drubbed by conventional wisdom purveryors here, Pete Putman the HDTVexpert, doesnt seem daunted about using his CM 7777 amplifier....at stations 20 miles away with medium gain antennas. In fact from this and other test on indoor antennas that he has done in the past, it seems to indicate that the CM7777 in fact is helping much more than hurting reception....with nice 8VSB waveforms I might add. In fact in this particular article, the CM7777 makes the Winegard 269 look bad.



Specifically this chart....in which all antennas are amped with the CM7777 or have no amplifier....except for the Winegard SS2000 which is a SS1000 with a Winegard 269 amplifier....allowing for direct comparison. Additionally, look at the figures for the other antennas which all bring in many more channels with good clean signals than unamped.

Call me a uppity newbie, but Ill stick with my recommendation.

http://www.hdtvexpert.com/images_c/5antennas_2.gif
The SS1000/2000 has got to be the world's worst UHF (& VHF) antenna...
in both performance and price...and a Preamp won't help either...
See Bob Chases's on-air comparison test:
http://www.avsforum.com/avs-vb/showthread.php?p=9332997

45 miles from the towers is the boonies.

I have a CM7777 hoooked up to a CM4221 and 50ft of RG6....most stations at -70dbm one at -40dbm, no problems here.

But I understand your assertion. Perhaps the 269 is the way to go, but he has in his possession a CM7777 and a RS 4 way distro amp. Of those 2, Id try the CM7777 first, by itself.My basic point is that it is usually best to go on the conservative side when amplifying DTV signals. The 7777 may in fact work for the OP. He may find it works better by placing it after the grounding block if there are overloading issues once the antenna comes out of the attic. I would personally rather use the appropriate pre-amp rather than worry about trying to start attenuating signals. It kind of defeats the purpose of amplifying right at the antenna in the first place.

I was hoping to finally be able to use the very forgiving Winegard HDP-269 at my location once the analogs went dark. I still "lose" one very weak station once the pre-amp is added into the system anywhere near the antenna.

Here is a chart on digtalhome, that holl_ands did some figuring on, with max input with 2 strong signals and amplifier overload. (plus additional figures for 3 strong signals and so on and so forth).

http://www.digitalhome.ca/forum/attachment.php?attachmentid=540&d=1229323619

Looks like with just one station at -28dbm (Real Channel 23 Telemundo) he should be OK. If you include the other 2 which are also off axis at 100 and 3 degrees (which helps attenuate the antenna gain), I think he is still in the game....you can always add the amp in down the line or run an attenuator from the attenna. Id stick with the CM7777.

For the CM7777 on UHF for 2 strong signals the overload figure is -36dbm.

I couldn't access the digitalhome forum; could EscapeVelocity supply a synopsis?

Since yesterday, I greatly improved my CT reception from the North by adding an amplifier (RS 259; not the best, I know, but convenient) and a VHF antenna for WTNH.

I also discovered that for my TV, if I type in the real RF channel number, a channel not picked up on the scan will appear. The only problem is if the number for the real channel is already used by another station as a virtual channel. This procedure allowed me to add several stations, including WNJN 51/50 in Montclair, NJ and WGGB 40 in Holyoke, MA.

Go here, you will have to register to download the pdf. They are really territorial over there. Ive noticed that a lot of Satelitte and AV forums are like that.

First post, attached file.

http://www.digitalhome.ca/forum/showthread.php?t=42426

I still need my basic technical questions answered:
1. How do you determine the RF signal level on the end of my cable, knowing all the antenna and amp gains and various losses, and the signal power at my location from TVfool.
2. How do I know if my amp is overloading.
3. Why is RG6 considered better than RG59 and both better than twin lead. I thought twin lead has the lowest loss, and in a low-interference noise environment, that should be better. On the other hand, for short runs (<20 feet), cable loss shouldn't be a factor.
4. At my location, I still can't get receive WPIX-RF11 (power level -67.3), while WNET-RF13 (Pwr -67.1) comes in like gangbusters. Both transmitters are on the Empire State Building, so I should get the signal almost equally well with my channel 13 folded dipole antenna, unless TVfool is wrong and WPIX is not putting out the ERP TVfool used for their calculation.

Thanks, everyone

I still need my basic technical questions answered:

4. At my location, I still can't get receive WPIX-RF11 (power level -67.3), while WNET-RF13 (Pwr -67.1) comes in like gangbusters. Both transmitters are on the Empire State Building, so I should get the signal almost equally well with my channel 13 folded dipole antenna, unless TVfool is wrong and WPIX is not putting out the ERP TVfool used for their calculation.

The transmit antennas on the ESB are not really omnidirectional.

1. Measure them with a signal analyzer.
2. Measure them with a signal analyzer.
3. RG6 isnt that much more expensive, its a no brainer....might as well get quad shielding as well.
4. Radio transmissions on different frequencies from different transmitters and recieved by whatever antenna at whatever location with a myriad of materials, trees, hills, obstructions, interference ad naseum.... are devious like that. (PS, TVfool is not the God given truth....accurately reflecting reality).

Maybe someone else can help you with better answers.

I got the preamp comparison chart EscapeVelocity recommended. It also answers my first question, above: - take the TVfool Receive Signal in dBm, add the various gains, and subtract the losses. Since they say to convert to Peak power by adding 7 dB, is that the value we want to use?

Yes, but I wouldnt fret over it too much MTVhike, you have the CM7777 in your possession, work on the rest of the system. In the future you can purchase a 269 if you are feeling deprived of something.


What you cant do is know exactly what the real signal level is going into the preamp without a signal analyzer. You are guessing on transmission (via TVfool, plus attic building material losses, and antenna anomalies and averaged or smoothed gain figures, VSWR, off axis antenna gain attenuation etc).

My strongest signal from the West is WLIW-21 at -49.8. Adding the antenna gain of 10.8 dB gives -39; adding another 7 for peak power and another 6 for other losses (guess), gives -24. The overload signal level for the CM7777 is -38.8, so I guess I don't have a problem, right?

I posted this before I got the message from Escape Velocity, above. I am fretting about this so I can resolve these issues before I climb onto my 45 degree, 50 foot high roof!

I think in your calculation you add the 7 for peak power.
John

Preamp Overload Calculator, with detailed explanations, can be found here:
www.imageevent.com/holl_ands/files

I think in your calculation you add the 7 for peak power.
John

I think I calculated the overload level wrong. My strongest signal from the West is WLIW-21 at -49.8. Adding the antenna gain of 10.8 dB gives -39, and subtracting 6 dB for other losses; (guess), gives -45 dB. To convert to peak level, I have to add 7 dB, giving -38. The overload signal level for the CM7777 is -38.8, so it looks as if I will overload the preamp by 0.8 dB; however, the next strongest signal in that direction is 15 dB weaker, so it looks as if I will just squeak by, right? Right now, I am getting 70% signal; if I add a splitter as a 3.5 dB attenuator and the signal gets better, I guess I was overloading; if not, I wasn't.

Thanks, again

I still need my basic technical questions answered:
1. How do you determine the RF signal level on the end of my cable, knowing all the antenna and amp gains and various losses, and the signal power at my location from TVfool.

http://www.hdtvprimer.com/ANTENNAS/sizing.html


3. Why is RG6 considered better than RG59 and both better than twin lead. I thought twin lead has the lowest loss, and in a low-interference noise environment, that should be better. On the other hand, for short runs (<20 feet), cable loss shouldn't be a factor.


RG6 has less cable loss. For short runs RG59 would be fine I guess.

Twin lead doesn't match the impedence of most antennas so you need a balun at both ends, so you would have more balun loss. Also, it's not shielded, so it seems it would pick up more noise. Anything can contribute to noise and drown out your signals, including computers and any electronic devices in your home. Possibly your neighbors' as well.

I have found it best in the signal distribution system to get the right balance with the appropriate antenna and amplification and not use attenuation. You are just getting by with that setup. I tend to avoid all that stuff.
I've got a tricky situation where I'm trying to acquire stations on 2-edge down to around -114dBm and I have four locals at -31.6, -36.3, -37.1, and -47.9 LOS (two more (-47.7 & -47.9) will come on-line before the year is out).

I'm also feeding five recording devices from a 50' tower.

I've been using a CM7778 pre-amp (seperate inputs and FM trap on) with an RCA ANT1500 omni and rabbit ears spread to 30 inches for channel 9. RG6 runs from the attic to the power injector in the basement, then to my Zenith CECB (total run 50ft.) I have the flat side of the 1500 pointed toward Peoria to recieve those stations late at night (just in time for the news.) This has worked well for a single room until the foliage came out and extreme storms started. My ultimate plan is to recieve my locals plus Peoria and WSEC-DT maybe from the attic with enough strength for a few splits. I plan on adding a tower and maybe an XG-91 on a seperate run eventually for DXing. My question is if there is a better UHF omni or reflectorless wide angle around 90 degrees front and back. I would combine this with a narrow beam antenna for 331 to 348 degrees and a VHF cut for rf9. Any ideas?

http://www.hdtvprimer.com/ANTENNAS/sizing.html

RG6 has less cable loss. For short runs RG59 would be fine I guess.

Twin lead doesn't match the impedence of most antennas so you need a balun at both ends, so you would have more balun loss. Also, it's not shielded, so it seems it would pick up more noise. Anything can contribute to noise and drown out your signals, including computers and any electronic devices in your home. Possibly your neighbors' as well.
Twin lead suffers higher loss when placed next to other objects, such as
when routed through walls.
It also has much, much higher loss when wet....or damp....or iced over....
Plastic type also has a reputation for cracking over time, letting in moisture.
Open ladder line can avoid these latter two problems....except ice buildup....

PS: Since nearly all inputs today are coax, you're still gonna need a balun at the TV.
So EITHER has a single balun, whether at the TV with twin lead or at the antenna with coax.
And no, you don't avoid the balun loss if you use a 300-ohm input Preamp, cuz the
balun in INSIDE the Preamp, converting to unbalanced for input to the RF transistor.

Twin lead suffers higher loss when placed next to other objects, such as
when routed through walls.
It also has much, much higher loss when wet....or damp....or iced over....
Plastic type also has a reputation for cracking over time, letting in moisture.
Open ladder line can avoid these latter two problems....except ice buildup....

PS: Since nearly all inputs today are coax, you're still gonna need a balun at the TV.
So EITHER has a single balun, whether at the TV with twin lead or at the antenna with coax.
And no, you don't avoid the balun loss if you use a 300-ohm input Preamp, cuz the
balun in INSIDE the Preamp, converting to unbalanced for input to the RF transistor.

Currently I have a UHF antenna with a 7777 preamp mounted on its mast. I want to add a home made VHF dipole and install it about 6 - 10 feet away (horizontally). It's native impedance is 300 ohms, so should I put a balun on it and run RG6 or 59 to the VHF input of the preamp, or run twin lead to a balun on the preamp input?

Thanks, Mike

The loss over 6-10 feet using rg6 is negligible for vhf. Twist or solder each end of the twinlead to a lead on the balun at the antenna then run rg6 from there to the preamp.

I want to add a home made VHF dipole and install it about 6 - 10 feet away (horizontally). It's native impedance is 300 ohms, so should I put a balun on it and run RG6 or 59 to the VHF input of the preamp, or run twin lead to a balun on the preamp input?A dipole will be in the 50Ω - 70Ω range, a folded dipole will be in the 300Ω range.

If outdoors, the clear choice would be coax to balun at antenna vice twin-lead.
Either way, you need a balun....

If you haven't read it yet, I analyzed Hi-VHF Folded Dipoles and Square Loops here:
www.imageevent.com/holl_ands/yagis
Square Loop has slightly higher Net Gain, esp for larger wire/tubing sizes.
A Folded Dipole or a Square Loop is only $10 using 1/2-in Type M Copper Pipe and 4 Elbows.
[Smaller sizes are also usable, but SWR isn't as good on CH7 & CH13.]

Hi-VHF Circular Loop could be readily made using 5/16-in Copper Tubing, which is
already "bent". Analysis is on my "To-Do" list....

If outdoors, the clear choice would be coax to balun at antenna vice twin-lead.
Either way, you need a balun....

If you haven't read it yet, I analyzed Hi-VHF Folded Dipoles and Square Loops here:
www.imageevent.com/holl_ands/yagis
Square Loop has slightly higher Net Gain, esp for larger wire/tubing sizes.
A Folded Dipole or a Square Loop is only $10 using 1/2-in Type M Copper Pipe and 4 Elbows.
[Smaller sizes are also usable, but SWR isn't as good on CH7 & CH13.]

Hi-VHF Circular Loop could be readily made using 5/16-in Copper Tubing, which is
already "bent". Analysis is on my "To-Do" list....


Since I bought the AntennaCraft Y5713, what 75 Ohm Transformer should I use to connect my RG6 with? I really care about channels 7 and 11 the most. Would any 75 Ohm Transformer work?

Thanks.

I like the Channelmaster baluns. They are available at starkelectronics.com or at least they were the last I checked.

In case anyone is interested, the quad on top are Triax Unix 100A's (uhf 14-38 specific) and the bottom dual are Antennacraft Y10 7-13's (vhf 7-13). Combiners are Lindsay uhf quad and vhf dual models. Pre's are Sitco PA24 for uhf and CM7777 for vhf (vhf input only).

Since I bought the AntennaCraft Y5713, what 75 Ohm Transformer should I use to connect my RG6 with? I really care about channels 7 and 11 the most. Would any 75 Ohm Transformer work?

Thanks.
Specs for AntennaCraft Y5-7-13 say 300-ohm, so it requires a standard 4:1 300-to-75-ohm Balun.

Standard 300-to-75-ohm Baluns I measured several years ago were all under 1 dB for VHF,
but were quite a bit more at UHF, some more than others:
www.imageevent.com/holl_ands/files
[Accuracy is +/- 0.5 dB, since I no longer have access to a room full of Test Equipment.]

More recently, johnrmckee measured 0.5 dB VHF/UHF loss for the Outdoor Philips Balun.
http://www.avsforum.com/avs-vb/showthread.php?p=15851345

And that's about all we know.....until someone makes some more measurements...

Hi-VHF Circular Loop had slightly higher Raw & Net Gain than Square Loop,
despite slightly smaller diameter, using "3/8-in I.D." Copper Tubing (actual OD=0.514-in)
for Circular Loop & 1/2-in Type M Copper Pipe (OD=0.569-in) for Square Loop:
http://imageevent.com/holl_ands/yagis/sqloop
From the Square Loop results, you can see what happens with smaller tubing/wire sizes....

Since I bought the AntennaCraft Y5713, what 75 Ohm Transformer should I use to connect my RG6 with?From an earlier post by me:

It was mentioned that baluns with separate wire leads may have their performance degraded by the way the wire leads are dressed. That one is easy to avoid, use one of the models shown below. They have standard 300Ω twin lead wire on the input (or output) side.

Winegard TV-2900 Weatherproof Transformer, info here (http://www.winegard.com/offair/couplers.php)

MCM 33-040 Weather ResistantTransformer, info here (http://www.mcmelectronics.com/product/33-040)

If you want a balun with no insertion loss then build yourself a λ/2 coaxial cable balun. It is channel specific. Lets say you choose mid way in the VHF Hi-Band (≈ 195 MHz) then there will be about 0.5dB insertion loss at the band extremes, CH-7 and CH-13. It would require 24.82 inches of Belden 1694A or Belden 1505A coax.

Coax baluns are great in theory but they sure aren't easy to make. Coax shield wasn't intended for soldering.;)

Coax baluns are great in theory but they sure aren't easy to make. Coax shield wasn't intended for soldering.;)That is why I specified Belden 1694A (RG-6/U) or 1505A (RG-59). Both have a 95% TC (Tinned Copper) braid with 100% foil for shielding. The TC braid is very easy to solder. I used these two types for all of our SD-SDI (SMPTE 259M), HD-SDI (SMPTE 292M) and SMPTE 310 video feeds/distribution. They are overkill for general RF use and cost a lot more than a good solid copper center conductor cable with aluminum braid. Some info here (http://www.belden.com/pdfs/03Belden_Master_Catalog/21Residential_Cables/21.12_19.pdf) on 1694/1505.

FWIW, I use CommScope 5729 (http://www.commscope.com/company/eng/index.html) cable and Aguat SNS1P6 (http://www.tnb.com/ps/pubint/index.cgi?a=products) Snap-N-Seal (RG-6/U) connectors for all of my RF work. I use the referenced Belden cables for all video work.

There are several other RG-6/U and RG-59 cables available with tinned and un-tinned copper braid but it has been many years since I used any of these. For folks interested you may try Alpha Cable Co. or Clark Wire & Cable Co.

In case anyone is interested, the quad on top are Triax Unix 100A's (uhf 14-38 specific) and the bottom dual are Antennacraft Y10 7-13's (vhf 7-13). Combiners are Lindsay uhf quad and vhf dual models. Pre's are Sitco PA24 for uhf and CM7777 for vhf (vhf input only).

cpcat, nice new setup with the quad! I'm still using MAX HD's first two Triax Unix 100 W/B antennas horizontally stacked. I know MAX HD really likes his quad stack. Are you seeing stronger reception with the 4 antennas over 2 antennas? I'm wondering about 4 vs. 2 at my location with the local antenna farm 3-5 miles away. The stack certainly has allowed me to DX more stations. Might 4 help me even more in this high RF location?? Just curious. Thanks.

Steve

Below is the λ/2 coax balun I made for the Winegard PR-9032. It was constructed using a small black plastic box and tapped to the boon of the antenna.

http://farm4.static.flickr.com/3552/3695013880_31e3da324a_b.jpg

That is why I specified Belden 1694A (RG-6/U) or 1505A (RG-59). Both have a 95% TC (Tinned Copper) braid with 100% foil for shielding. The TC braid is very easy to solder. .

Gotcha. Good to know.

cpcat, nice new setup with the quad! I'm still using MAX HD's first two Triax Unix 100 W/B antennas horizontally stacked. I know MAX HD really likes his quad stack. Are you seeing stronger reception with the 4 antennas over 2 antennas? I'm wondering about 4 vs. 2 at my location with the local antenna farm 3-5 miles away. The stack certainly has allowed me to DX more stations. Might 4 help me even more in this high RF location?? Just curious. Thanks.

Steve

Yes, it's certainly a noticeable difference . The beamwidth is very narrow which should actually help with your local strong signals. I doubt the extra gain in itself would be enough to produce problems if you aren't having any already.

MaxHD is stacked at around 40 inches if I'm not mistaken. I'd like to have that kind of room but unfortunately am maxxed at around 27 inches with my current fiberglass length.

Hi-VHF Circular Loop had slightly higher Raw & Net Gain than Square Loop,
despite slightly smaller diameter, using "3/8-in I.D." Copper Tubing (actual OD=0.514-in)
for Circular Loop & 1/2-in Type M Copper Pipe (OD=0.569-in) for Square Loop:
http://imageevent.com/holl_ands/yagis/sqloop
From the Square Loop results, you can see what happens with smaller tubing/wire sizes....
holl_ands,

Can you prioritize the reflector modelling on the circular design? Any thoughts on what a director would look like?

Is there a specific size for maximizing RF channel 8 reception?

What do you think the design for RF 32, RF 23, and RF 47 would be using 10 AWG (solid copper)?

I would think these would be very easy to box with shielding.

http://www.soontai.com/TRF.html

Has anyone used these and where can I find them?

I have an e-mail into the company now.

Anyone know where I can get bulk quantities of the Channel Master 3072's and 3075's?
These appear to be like the CM3075 for a lot less.
http://www.sadoun.com/Sat/Products/JVI/45-MT2_JVI_Outdoor_Matching_xFormer_with_weather_boot.htm

Recommend some twinlead 300 ohm wire.

Radio Shack has some. Is there any better quality to be had? Is older vintage stuff better?

Thanks!

I use Channel Master 9354 300 ohm cable.

http://www.moyerelectronics.com/index.shtml?http://www.moyerelectronics.com/Channel_Master/CoaxialWire.html (by the foot)

You can also find it at http://www.hbfelectronics.com/index.php?action=disp_item&item_id=287193 (best price) or http://www.starkelectronic.com/

Recommend some twinlead 300 ohm wire.

Radio Shack has some. Is there any better quality to be had? Is older vintage stuff better?I use Channel Master 3055. It is a low loss foam type. Unfortunately, it has been discontinued. CM does not list any 300Ω twin-lead in their current catalog. Some may be available here (http://www.encompassparts.com/products/?CMA3055). The Rat Shack list the 15-1175 as a foam type and probably is similar to the CM wire.

Although I couldn't find any loss specs for C-M or R-S cables, I did find the following:
http://www.avsforum.com/avs-vb/showthread.php?p=15969694

WWWAAAAYYY back when, the "best" low loss 300-ohm cable had a round hollow (air) core,
rather than the somewhat higher loss foam core typically found today. Worst was plastic junk....

holl_ands,

Can you prioritize the reflector modelling on the circular design? Any thoughts on what a director would look like?

Is there a specific size for maximizing RF channel 8 reception?

What do you think the design for RF 32, RF 23, and RF 47 would be using 10 AWG (solid copper)?

I would think these would be very easy to box with shielding.
Still working on the Dual Loop (UHF/Hi-VHF) design....adding a reflector will be next....

There is no need to "tune" the design across the Hi-VHF band....SWR/Gain doesn't
change much....and optimizing SWR usually increases Raw Gain....

Standard Yagi sizes are 5% longer for Reflector (at 0.15 to 0.2 wavelength spacing)
and 5% shorter for Director (at about 0.15 wavelength spacing)...give or take...
Square Loop Yagis....and esp. Quagi's (two loops + rod directors) are fairly common:
http://commfaculty.fullerton.edu/woverbeck/quagi.htm

I still need to re-optimize the Circular Loop diameter for smaller wire sizes, but if you
look at the Square Loop charts for various element sizes, the size shrunk by a few inches,
the Gain dropped as much as a dB and SWR increased some using smaller wire size.

Excellent read. Thanks holl_ands.

Found an old Channel Master catalog. Here is the information on their 300Ω Transmission Line.

Channel Master Model 3055, 300 Ohm Twin-lead (3055 and 9354 is the same, 3055 is various hank lengths and 9354 is 500 ft. spool). The wire is 20 gauge, 7 strand pure copper.

dB Loss per 100 Feet

MHz-- 57 85 177 213 500 650 800 900
Dry-- 0.9 1.2 1.5 2.0 3.2 3.8 4.5 5.4
Wet-- 1.3 1.7 2.3 3.2 7.2 9.5 11.1 13.5

FWIW, I only use a short piece of this wire. It goes from the 300Ω antenna connection to a λ/2 coax balun (about 10").

So C-M 9354/3055 appears to be the lowest loss...for twinlead....
But that doesn't include losses due to proximity to other objects....

So RG6 is still looking like the best overall choice for downlead....esp. when it's damp outside...
And of course if you're using a Preamp, these small difference are even smaller....

Stampeder @ digitalhome.ca said:

I saw a great post about antennas in attics on another forum that linked to a post on another forum from Bob Chase, a broadcast technician who regularly comments on OTA antennas and stuff over on AVSForum:

Quote:Attics take a huge toll on the signal you get. The few that I have measured so far have been in the 20 dB range of attenuation. Those attics are made of standard asphalt shingles, over roofing felt, over plywood type construction. I have not been in an attic like yours.

Attics also cause reflections that the HDTV tuner has to equalize out and there is only so much equalization that is available. So that means there is less equalization available for the 'real world' multipath that is arriving over your house.

Some folks have good luck with the Channel Master CM7777 preamp. Inside the attic it is pretty hard to overload the front end of that particular amp. (Outside it can happen quite easily.) Given the right conditions, preamp will not overload but the output of the amp can overload the HDTV tuner . That is just one of the good reasons for using an attenuator at the receiver.

http://www.digitalhome.ca/forum/showthread.php?t=29559

Yes, but I wouldnt fret over it too much MTVhike, you have the CM7777 in your possession, work on the rest of the system. In the future you can purchase a 269 if you are feeling deprived of something.


What you cant do is know exactly what the real signal level is going into the preamp without a signal analyzer. You are guessing on transmission (via TVfool, plus attic building material losses, and antenna anomalies and averaged or smoothed gain figures, VSWR, off axis antenna gain attenuation etc).

I am continuing to try to figure out how gains affect digital signals, and did some tests yesterday (7/12). I borrowed an old Jerrold 727 "Field Strength Meter", to make some measurements (unfortunately, this meter is VHF only). In CT, WTNH is now running on RF channel 10. It is about 35 miles away, with a TVfool signal strength of -52.5 dBm. Using a simple rabbit ears oriented correctly in my attic window and no amplification, I get no reading on the 727, nor on my TV. I purchased a RadioShack model 259 preamp and get 1 bar on my TV. The 727 reads 24 dBm with the RS gain at minimum, and 34 with it at max. I then added my older RS splitter, and got 40 dBm with its gain at a minimum and 55 with it at max. These readings suggest that the amps are working correctly. However, the TV is still giving only 1 bar, and it is barely watchable. Since I am increasing the gain from 0 to 55 dB in roughly 10 dB steps, I can't see how overload could be the problem. I do have a strong FM station at 91 MHz (Signal strength 79 dB with both traps out, and 46 with both traps in). Could that be the problem? Thanks

Sometimes, I get a good signal from WTNH with my channel 13 dipole on the SW side of my house using my CM7777 (no splitter). Is this because the 7777 is a much better preamp than the RS one?

Finally, since I have both UHF and VHF antennas on the NE side, I tried a RS UHF/VHF combiner (model 2586). It did not seem to attenuate the VHF signal at all (the signal strength meter can see changes less than 1 dB). Do these combiners with separate UHF and VHF inputs normally have such a low loss?

Mike

What CECB are you using?

Are your FM traps tunable? If so, they may need to be adjusted (mine did).

So C-M 9354/3055 appears to be the lowest loss...for twinlead....I would never use 300Ω twin-lead if there was a way to avoid it.

I can think of one use, very long runs of 300Ω ladder line. It looks similar to this ladder line (http://www.dxengineering.com/Sections.asp?ID=93&DeptID=36#Top) but uses small plastic rods to keep the wires separated. This type of twin lead had very low loss (wet loss ?), however, I have not seen this wire in a while and do not know if it is available. It was used in mountainous regions where the antenna would be on high point and the residence would be several hundred feet down the side of the mountain.

Here is some info on some low noise amplifiers for VHF and UHF bands....

LNA antenna preamp from Kitztech

http://www.avsforum.com/avs-vb/showthread.php?t=820382

I found this on Ken Nists (HDTVprimer) site....

(Tom, at www.hdtvtruckee.com, has tested splitters, and the Perfect Vision PV22-233 was the best he found, averaging a roughly 0.5 dB loss (0.5 dB beyond what is expected for an ideal device). I have not tested it. I suspect it is also sold under other names.)

http://www.hdtvprimer.com/ANTENNAS/TemporaryPage.html

For these tests I chose a Radio Shack Model 15-1234 "Hybrid Splitter Combiner", which is actually among the better performing splitters I've measured. [Its response is almost identical to a Pico Macom MS-2D, which causes me to wonder if Pico Macom is actually the manufacturer].

http://www.hdtvtruckee.com/CombinerMeasurement.htm

I would never use 300Ω twin-lead if there was a way to avoid it.

I can think of one use, very long runs of 300Ω ladder line. It looks similar to this ladder line (http://www.dxengineering.com/Sections.asp?ID=93&DeptID=36#Top) but uses small plastic rods to keep the wires separated. This type of twin lead had very low loss (wet loss ?), however, I have not seen this wire in a while and do not know if it is available. It was used in mountainous regions where the antenna would be on high point and the residence would be several hundred feet down the side of the mountain.
Link to Wet/Dry Loss Calculator for many cables, incl Wireman Ladder Line is here:
http://www.avsforum.com/avs-vb/showthread.php?p=15969694
Also includes link to Wireman, who sells Model#562 (300-ohm open ladder line) for 30 cents/ft.

Although #562 isn't included in the on-line loss calculator, it should be close to #551,
which has similar construction (2.15 dB/100ft DRY and 51.7 dB/100ft WET at 700 MHz).
YIKES!!!! Best to let the Ham radio guys us it on their HF rigs below 30 MHz....
[That's worst case, encased in snow or ice....]

What CECB are you using?

Are your FM traps tunable? If so, they may need to be adjusted (mine did).
I am using a Samsung TV with ATSC tuner. The FM traps are not tunable.

[QUOTE=Rick0725;16811589]the rs 15-2586 is a standard full band tv splitter/combiner. you would use a uvsj vhf/uhf band combiner splitter to combine a uhf and vhf antenna. Preamps like the cm7777 have this circuit built in.

I have a CM7777 in use on my other antenna system; I was just trying a cheap-and-dirty system locally available at RS. I was really trying to find out why adding roughly 50 dB of gain, as measured with my signal strength meter, didn't help my Samsung ATSC tuner pick up the station any better. Based on other comments here, I am concluding that it is the strong FM station.

Mike

the rs 15-2586 is a standard full band tv splitter/combiner. you would use a uvsj vhf/uhf band combiner splitter to combine a uhf and vhf antenna. Preamps like the cm7777 have this circuit built in.

http://www.solidsignal.com/prod_display.asp?PROD=UVSJ

The 15-2586 is a VHF/UHF diplexer, same as the UVSJ from Solid Signal. It is NOT a full-band splitter as the website description incorrectly implies.

[QUOTE=Rick0725;16811589]I was really trying to find out why adding roughly 50 dB of gain, as measured with my signal strength meter, didn't help my Samsung ATSC tuner pick up the station any better.FWIW, my Samsung LCD is more sensitive to overload than any CECB or ATSC TV I have used.

I was just trying a cheap-and-dirty system locally available at RS. I was really trying to find out why adding roughly 50 dB of gain, as measured with my signal strength meter, didn't help my Samsung ATSC tuner pick up the station any better. Based on other comments here, I am concluding that it is the strong FM station.

More likely that increasing the gain just isn't improving your signal-to-noise ratio (SNR). For the most part, the SNR of your system is set by your antenna gain and the noise figure of your pre-amp. Pre-amp gain has little effect because it amplifies noise right along with the signal, keeping the SNR about the same.

Alternatively it could be something like multi-path. Again, a stronger (higher gain) amp wouldn't help because it's amplifying the multi-path signal as much as the main-path signal.

(Strong FM station)Could that be the problem? Thanks

Yes it could be increasing the noise in your pre amp as it overloads across all frequencies.

Sometimes, I get a good signal from WTNH with my channel 13 dipole on the SW side of my house using my CM7777 (no splitter). Is this because the 7777 is a much better preamp than the RS one?


Sounds to me like you only get it sometimes, its because of the antenna gain and signal strength or other issues.....and not the amps (which cant create something out of nothing). However if you never get a signal with the RS and sometimes do with the 7777 all other things being equal, that is probably the difference in the noise of the amps. And that means you need a better antenna or location for the antenna.

Finally, since I have both UHF and VHF antennas on the NE side, I tried a RS UHF/VHF combiner (model 2586). It did not seem to attenuate the VHF signal at all (the signal strength meter can see changes less than 1 dB). Do these combiners with separate UHF and VHF inputs normally have such a low loss?

Yes. They typically have an insertion loss of .7db plus or minus less than half a db.



FWIU.

Signal strength for transmitted signals is expressed in dbm, like on tvfool, but on the receive end signal strength is usually expressed in dbmv, where 0 dbmv equals 1mV. This is what I am familiar with and how the meters I use work. Tv tuners can handle up to about +25dbmv/18mV (per carrier). Analogue signals get snowy below around -6dbmv. Cable carriers shoot for +10dbmv at the house, which can be safely connected to a tuner or split about 3 ways without further amplification. 0dbmv was a level MATV installers used to shoot for at the tv set. My signal strength meter measures down to around -30dbmv. If you are that low coming staight off the antenna, you are probably going to have problems with any preamp. Preamps need something to work with. Antenna preamps are a science of their own, but I don't think you are going to overload most preamps unless multiple carriers are greater than +10dbmv. Nearby FM transmitters can cause problems for VHF channels on each side of them.
I abandoned OTA TV for cable over 25 years ago, but have come back since digital broadcast started. I finally bit the bullet and got a Sadelco Display Max signal strength meter to study what is up with digital reception. It has a spectrum analyzer feature. Digital signals seem to be more about clean (low multipath) than signal strength. If I see a notch in the flat-topped waveform approaching 10db deep, or if the front or back edge is rolled off there is going to be problems with the signal if it deteriorates any further, if not already. I have locked on reliably to signals as low as -16 to -20 dbmv. Also, there is a real time single-frequency level mode for tweaking antennas. If the level is bouncing around wildly, like when the wind is blowing, there will usually be problems, especially if the signal is weak. Even with all of this, conditions can change drastically from day to day. But I am in the city, with a lot of huge trees.
I did notice on my Sam digatal tuner, that 3-4 bars means around -20dbmv signal; 8 bars = -7; and 9 bars = 0dbmv or greater, which is nothing more than an indication of what is going on.
I am definitely no expert and there is no substitute for experience, which is what is good about forums like this.

That's a fantastic post! Thank dbdoc.

you are correct. went to the store down the street today and the legs are labeled uhf/vhf on part# 15-2586. That is alot of money for one of those.

It takes a lot of money to stock and man a B&M store. It's called RETAIL.

If you want cheap prices, buy from someone online with no overhead, no manpower, and no stockholders to answer to.

CONVERTING BETWEEN dBmV and dBm:
http://www.soontai.com.tw/cal_exunit.html
http://www.maxim-ic.com/appnotes.cfm/an_pk/808/

so for 75-ohm load:
dBm = dBmV - 48.8 dB
dBmV = dBm + 48.8 dB

Cable carriers shoot for +10dbmv at the house, which can be safely connected to a tuner or split about 3 ways without further amplification. 0dbmv was a level MATV installers used to shoot for at the tv set.
When I was designing cable plants, the standard was 0dBmV ±10dB at the outlet. I think this may also be an FCC requirement.

By that he means Zero (0) as in:
so for 75-ohm load:
0 dBm = dBmV - 48.8 dB
0 dBmV = dBm + 48.8 dB

For all readers. IMO, the easy way to do things like this is to enter the equations into your spreadsheet. I have some of these in Quattro Pro (should work in Excel or OpenDoc, etc.)

It's an algebraic equation. If you plug +10 dBmV into "dBmV" , you find:

dBm = dBmV - 48.8 dB
dBm = +10 dBmV - 48.8 dB
dBm = -38.8 dBm

Hence +10 dBmV = -38.8 dBm

As you might expect, OTA signal levels are much lower than cable signal levels.
But we should not compare them directly. Here are specs:
http://www.avsforum.com/avs-vb/showthread.php?p=8138883

Standard 256QAM levels are -12 to +15 dBmV (-60.8 to -33.8 dBm).
Typical cable boxes will lose the signal if it's lower than this and
will suffer from overload at higher levels--esp. since there are over
a hundred strong, equal strength carriers on cable.
Obviously, you would want the signal at the cable entry point to be
towards higher end of this range, due to 4 dB loss in each RF Splitter.

Unlike OTA which may have only a handful of strong, unequal strength carriers.

Actually, when I said cable providers shoot for +10, it is what I have observed for analogue cable. On TWC feeds in KCMO, it is easy to see where analogue ends and the digitital channels begin on a full scan meter display because they are running the digital carriers around 7db less than the analoge ones.
I can't believe all the years I have read books and experimented to get knowledge in this area. Now you can hop on the internet and find it all. It has been interesting to go back and read some of these threads from the beginning to fill in the gaps.

You have to be careful comparing apples and oranges.
Analog is always specified and measured using a PEAK reading meter.
DTV is always specified and should be measured using an AVERAGE reading meter.
Peak-to-Average Ratio for DTV is about 7 dB, whereas it's a variable for NTSC,
ranging from 2.2 dB (all black) to 7.6 dB (all white):
http://www.broadcastpapers.com/whitepapers/HarrisAnalogDigitalTransmitters.pdf?CFID=35361629&CFTOKEN=bf05eb97e3b664ab-732981B3-C644-F0C4-A7C30554EDFCE82C

Here's an AppNote for setting NTSC and DTV levels on CATV fibre illustrating
the PEAK vs AVERAGE measurement differences:
http://www.sunrisetelecom.com/support/cr1200r_apnote.pdf

Meters and Spectrum Analyzers will give different results, depending on the
bandwidth of the measurement filter, which is usually much less than 6 MHz:
http://www.pi-usa.com/pdf/dtva.pdf

You have to be careful comparing apples and oranges.
Analog is always specified and measured using a PEAK reading meter.
DTV is always specified and should be measured using an AVERAGE reading meter.
Peak-to-Average Ratio for DTV is about 7 dB, whereas it's a variable for NTSC,
ranging from 2.2 dB (all black) to 7.6 dB (all white):
http://www.broadcastpapers.com/whitepapers/HarrisAnalogDigitalTransmitters.pdf?CFID=35361629&CFTOKEN=bf05eb97e3b664ab-732981B3-C644-F0C4-A7C30554EDFCE82C

Here's an AppNote for setting NTSC and DTV levels on CATV fibre illustrating
the PEAK vs AVERAGE measurement differences:
http://www.sunrisetelecom.com/support/cr1200r_apnote.pdf

Meters and Spectrum Analyzers will give different results, depending on the
bandwidth of the measurement filter, which is usually much less than 6 MHz:
http://www.pi-usa.com/pdf/dtva.pdf

That last app-note was from 1997 and is related to using NTSC meters for measuring ATSC signals. We've certainly come a long way since then.....

The professional meters (Sadelco, Sencore, Leader, etc) have different configuration settings for analog vs digital that take the peak vs. average into account when displaying results. Still, the needed (final) digital signal level is comparatively lower than for analog as ATSC will easily decode down to around -35 to -38 dBmV as long as there is adequate C/N ratio (> 15.2 - 15.3 dB) and good enough quality (little peak/valley distortion that raises the BER). NTSC would have started getting grainy (loss of resolution) between 0 and -10 dBmV)

Also, keep in mind that TVfool and the FCC mapping tool provide estimates of signal POWER, not voltage. To convert from the projected power value to voltage (as measured with a dB voltmeter), add 48.8 to the dBm value to convert to dBmV (into a 75 ohm load).

As an example, if the forecast signal strength were -48.8 dBm, a unity gain (0 dB) antenna were used, and the circuit were perfect (no losses or mismatches), the dB voltmeter should read 0 dBmV, a -58.8 dBm forecast should read -10 dBmV, a -38.8 dBm forecast should read +10 dBmv, etc

Since no one here is likely to be working on optical front ends and signal measurements there-in, this app-note is afar more relevant to this audience: www.sencore.com/uploads/files/Analyzing_Signal_Quality_of_TV_RF_Signals.pdf

Here's another one that's pretty conservative with recommended signal levels: www.sencore.com/uploads/files/AchieveGoodHDTV.pdf

Great info, all. Test equipment is only as reliable as the knowledge of the operator. I am lucky to have a modern instrument that makes it much easier. It gives the voltage level of digital signals in center value or average value, depending on mode. And seeing the waveform explains exactly why these two values might be much different.
Sencore has great tech info. Their "Seeing is Believing" on spectrum analyzers a few years ago convinced me to get a signal level meter with a spectrum display as well as the spectrum analyzer feature.

Since no one here is likely to be working on optical front ends and signal measurements there-in, this app-note is afar more relevant to this audience: www.sencore.com/uploads/files/Analyzing_Signal_Quality_of_TV_RF_Signals.pdf

Here's another one that's pretty conservative with recommended signal levels: www.sencore.com/uploads/files/AchieveGoodHDTV.pdf
Those articles are two of my favorites. But I also like this one because I have found that old signal level meters designed for analog signals are still useful for digital signals:
Meters and Spectrum Analyzers will give different results, depending on the
bandwidth of the measurement filter, which is usually much less than 6 MHz:
http://www.pi-usa.com/pdf/dtva.pdf
--------------------------------------------------------------------------------------------------
Also, keep in mind that TVfool and the FCC mapping tool provide estimates of signal POWER, not voltage. To convert from the projected power value to voltage (as measured with a dB voltmeter), add 48.8 to the dBm value to convert to dBmV (into a 75 ohm load).

As an example, if the forecast signal strength were -48.8 dBm, a unity gain (0 dB) antenna were used, and the circuit were perfect (no losses or mismatches), the dB voltmeter should read 0 dBmV, a -58.8 dBm forecast should read -10 dBmV, a -38.8 dBm forecast should read +10 dBmv, etc
Your conversion factor of 48.8 is correct when going from dBm to dBmV, but there is no such thing as a dB voltmeter. Decibels express a difference in power levels. If not, how could you use the constant conversion factor when going from dBm to dBmV?

Signal level meters that are calibrated in dBm and dBmV both measure signal power, not voltage. Each uses a different reference level to compare with the signal to be measured, but the difference between these two reference levels is constant. That is what makes it possible to use the conversion factor:

The 0 dBm reference level = 1 mW

Converting the 0 dBmV reference level also to power (E squared divided by R):
0 dBmV reference level = 1.33333E-05 mW

This could also be stated as 0.0000133333 mW, but using the powers-of-ten engineering notation as above makes it possible to retain more significant figures on the average handheld scientific calculator. (You can also say it as "1.33333 times ten to the minus five milliwatts.")

dB ratio = 10 log (P1/P2)

= 10 log (1/1.33333E-05)

= 48.7506 dB

The dB ratio could have also been calculated using the voltages from each reference level and the formula dB = 20 log (E1/E2), but the reference level for dBm is by definition 1 mW of power. If we convert the reference level for dBm to voltage the impedance must also be 75 ohms. The reference level voltage for 0 dBm for 75 ohms is 0.274 Vrms, but it is 0.224 Vrms for 50 ohms.

To quote the ARRL Handbook:
Sometimes there is confusion about whether the decibel was calculated using power, voltage or current. Since the current and voltage equations use 20 instead of 10 times the log term, some hams believe the "voltage" or "current" decibel is different than one calculated using power. This is not true, however. There is ony one decibel definition, and that is ten times the log of a power ratio.
I like to use these two sites when making conversions:
http://www.soontai.com.tw/cal_exunit.html

http://www.jneuhaus.com/volts_to_dBm.html

Signals that are stronger than the reference level are assigned a positive value. Signals that are weaker than the reference level are assigned a negative value. Signals that are equal to the reference level are assigned a zero value (which doesn't mean no signal). The accuracy of the meter depends upon its calibration and the standards used for calibration.

Fortunately, we don't need to know the absolute value of the power measurement to a high degree of accuracy because most of our measurements are comparisons to find the strongest signal when aiming an antenna, finding the best location for an antenna, comparing antennas, and measuring loss in a distribution system. When making comparisons, meter linearity is important. This is easily checked with a built-in or external fixed attenuator.

A signal level meter (SLM) that uses a dB scale with a reference level of 1mV across 75 ohms for 0 dBmV is a relative power meter, not a voltmeter. It allows us to measure signal levels in dBmV, cable loss in dB, amplifier gain in dB, and make dB comparisons of antennas---all differences in power, not voltage. It's very convenient, because you can easily add or subtract decibel values. The "V" in dBmV is only to tell us what reference level is being used.

The older field strength meters (FSM) that came before the SLMs calibrated in dBmV used microvolts. They WERE signal voltmeters, and used the same reference level of 1000 microvolts (equals 1mV), but the scale was calibrated in microvolts. The later field strength meters included a dB scale along with the microvolt scale, which was the transition instrument between the early field strength meters and the present SLMs:

http://i496.photobucket.com/albums/rr328/rabbit73_photos/img027_1.jpg

Notice that 10 times the voltage gives a 20 dB difference in power. This explains why some of the early field strength meters, calibrated in microvolts, had 20 dB attenuators marked with the label "10," for ten times the voltage.

A meter scale can be calibrated in any units that are appropriate for the application. Which scale you use determines what you name the meter. If you use the microvolts scale you can call it a voltmeter. If you use the dB scale, it becomes a relative power meter.

So, your meter to measure signals can be calibrated in microvolts, dB, dBmV, or as in the photo above with two scales: one for microvolts and one for dB (but not "dB microvolts"). I don't think there is such a thing as a "dB voltmeter" because I'm not aware of a measurement unit called "dB volt."

Many years ago I attended a seminar led by Gordon Gow, longtime president of McIntosh Laboratory (mfg of high-end high-fi equipment). Whenever he hired a new EE as an employee, he had to sit him down to talk about decibels and invariably had to tell him that "there is no such thing as a voltage decibel. Decibels indicate a POWER ratio."

A measurement unit cannot be an expression of power and voltage at the same time; it is not consistent with Ohm's Law. Given enough information, one can be calculated from the other, but they are not synonymous. Please look at the screen shot below of digital channel 31 from my Sadelco DisplayMax 800 and note that the reading of +13.4 dBmV is labeled PWR:

http://i496.photobucket.com/albums/rr328/rabbit73_photos/IMG_0218copy_edited-1_1.jpg

QED

Yes, my SLM does refer to the average level of a digital signal as the power level of the channel.

Your conversion factor of 48.8 is correct when going from dBm to dBmV, but there is no such thing as a dB voltmeter. Decibels express a difference in power levels. If not, how could you use the constant conversion factor when going from dBm to dBmV?

Thanks for noting my imprecise terminology! I should have referred to it simply as a Signal Level Meter (SLM) for accuracy.

Nice seeing that meter scale. Makes it easier to understand.

Ah, my head hurts ... I'll have to think about this.

Your conversion factor of 48.8 is correct when going from dBm to dBmV, but there is no such thing as a dB voltmeter.I disagree in the general term, since Wikipedia has a fairly good description here (http://en.wikipedia.org/wiki/Decibel) I will not attempt my own view. More can be found here (http://www.sengpielaudio.com/calculator-db-volt.htm).

I will say there are very few thermal reading meters (true power) available. Most meters with dBm scales are simply Volt meters with dBm scales. The reading is correct as long as the reference load is correct. There are many dB meters and they too are just volt meters with dB scales.

This is correct: I measured the audio level and it is +4 dBm (600 Ω load)
This is incorrect: I measured the audio level and it is +4 dBm (10K Ω load)
This is correct: I measured the audio level and it is +4 dBu (10K Ω load)
This is correct: I measured the audio level and it is +4 dBu (1K Ω load)

In all four examples the actual voltage across the load should be 1.23 volts.

There is an old expression “a dB is a dB”.

I have recently installed a new Winegard AP 8275 preamp and power unit (replacing an exact model 20 years old), new 300 ohm balun, and RG-6 downlead on my (approx) 25 ft outside antenna, the same combination that I have used for the past 20 years, except for previously using RG-59 for the downlead. Strangest thing is, when using the AP 8275 preamp and power unit, I receive NO channels or FM signal. However, I receive generall good channel signals and FM reception when I remove the (tower) pre-amp. The attic installed power unit seems to have no effect, etc.

Strangest thing is, as noted above, I have used this combination for 20 years (same, older preamp [model Windgard AP 8775] minus the RG-6 and using RG-59), and everything worked normally.

I am not electronically qualified, but (being an old, non-active ham) have been rigging my own antennas, etc., for years, and find this perplexing, to say the least! Could the advent of DTV have increased the likelyhood of overload to the extent that the implementation of RG-6 is the causal factor?

Any hints would be appreciated!

C D Cook

Any hints would be appreciated!Double check your connections to the power inserter, check the DC out of the power inserter (spigot labeled ANT). If all is good then you may have a defective pre-amp. And there is the possibility that it is overloaded.

I disagree in the general term, since Wikipedia has a fairly good description here (http://en.wikipedia.org/wiki/Decibel) I will not attempt my own view. More can be found here (http://www.sengpielaudio.com/calculator-db-volt.htm).

I will say there are very few thermal reading meters (true power) available. Most meters with dBm scales are simply Volt meters with dBm scales. The reading is correct as long as the reference load is correct. There are many dB meters and they too are just volt meters with dB scales.

This is correct: I measured the audio level and it is +4 dBm (600 Ω load)
This is incorrect: I measured the audio level and it is +4 dBm (10K Ω load)
This is correct: I measured the audio level and it is +4 dBu (10K Ω load)
This is correct: I measured the audio level and it is +4 dBu (1K Ω load)

In all four examples the actual voltage across the load should be 1.23 volts.

There is an old expression “a dB is a dB”.
How very true, many "dBm" meters are simple high impedance voltmeters....illustrating
the importance of knowing exactly what you think you are measuring and with WHAT....

Some of the more expensive hand-held DVMs have a dBm scale selection,
normally used to measure AUDIO signals....hence ref impedance is 600 ohms.
But the load impedance is very high, so make sure the point you are measuring
is connected to a load...either another piece of equipment...or a 600-ohm resistor.

Most RF equipment (power meters, spec. analyzers) I've used were 50-ohm input,
presenting a load to whatever is being measured....hence dBm ref. impedance
was 50-ohms, meaning a calibrated 75-ohm to 50-ohm "Minimum Loss Pad"
is needed to make accurate measurements in a 75-ohm system. And (rarely) there
was a switch to disconnect the internal 50-ohm load....allowing an external load,
but the dBm scale was usually calibrated only for 50-ohms.

Some of the recent, more expensive, spec. analyzers actually have the ability
to SELECT the ref. impedance....greatly simplifying when I changed between
measuring audio (600-ohms) and RF (50-ohms).....or 75-ohms...

I've seen very few "True Thermal" power meters (actually measure the heat rise).
The best are "True RMS" power meters...which is somewhat different from "Average"
power measurements more frequently found in hand-held meters:
http://www.opamp-electronics.com/tutorials/measurements_of_ac_magnitude_2_01_03.htm

Any hints would be appreciated!
If you have a splitter between the pre-amp and power inserter, make sure the splitter leg that is being used has the capability to pass DC.

That brings to mind, did you get a new power inserter also? The old ones were A/C, while the new ones are DC.

Nice seeing that meter scale. Makes it easier to understand.
I'm glad that you found the photo helpful. My early measurements were made in microvolts. When I bought a new meter (Sadelco 719E) in 1988 that was calibrated in dBmV I put the photo in its storage compartment to help me convert my thinking from microvolts to dBmV. More recently, because of tvfool, I have had to think in terms of dBm. I use the factor of 50 to make a quick approximate conversion from dBm to dBmV.
Ah, my head hurts ... I'll have to think about this.
Sorry I made your head hurt.
I hope your head doesn't hurt even more now from information overload!

I didn't correct you to give you a hard time. I corrected you because I knew that the subject was important to you and that you are the type of person that wants to use the correct terminology.

My previous post with the meter scale edited for clarification---hope it is easier to understand. A post that involves semantics is one of the most difficult to do because the same words mean different things to different people.

Charles,

As to your question of whether the RG6 is what made the difference, the answer is a qualified "maybe".

The RG59, especially if old and degraded, might have been lossy enough to drop the signals below the overload level. The new RG6 would have eliminated that loss and pushed you back over the top.

Testing is easy. Just add a splitter or two (since they're common, cheap, and readily available almost anywhere) in series with your signal before it enters your TV or STB. Each splitter will drop the signal by 3.5 to 4 dB. If you find that it helps, either cap the unused port with a terminator or replace the splitter with a fixed or variable attenuator of the needed value.

holl_ands,

Can you prioritize the reflector modelling on the circular design? Any thoughts on what a director would look like?

Is there a specific size for maximizing RF channel 8 reception?

What do you think the design for RF 32, RF 23, and RF 47 would be using 10 AWG (solid copper)?

I would think these would be very easy to box with shielding.
I finished 4nec2 analysis of the Circular Loop plus Loop Reflector:
http://www.avsforum.com/avs-vb/showthread.php?p=16864417

Of course, different answers would result for a Screen or Rod Reflector(s)....
And adding one or more Rod Directors would turn the Dual Loop into a Quagi:
http://commfaculty.fullerton.edu/woverbeck/quagi.htm

Does anyone know where I can find information on the Archer 15-1108 UHF/VHF/FM amplifier? All I'm finding is the Radio Shack 15-1108 pre-amplifier.

Does anyone know where I can find information on the Archer 15-1108 UHF/VHF/FM amplifier? All I'm finding is the Radio Shack 15-1108 pre-amplifier.

Those appear to be the same thing.

I've got one. It's crap compared to my existing pre-amp.

Go to RS's website and enter the model number in the search box, the owner's manual is online.

It's not a pre-amplifier. Mine is 75 Ohm IN/OUT, Variable Gain, and is self-contained with an A/C cord.

According to the pix in the 2006 R Sh catalogue, there are two pieces to this. You have the indoor part. There is the part that mounts at the antenna and looks like it has a short 300 ohm input lead with coax connector for the output. The info says: typical VHF gain of 25db and UHF gain of 20db with 10db adjustment range, switchable FM trap and short-circuit protection.

According to the pix in the 2006 R Sh catalogue, there are two pieces to this. You have the indoor part. There is the part that mounts at the antenna and looks like it has a short 300 ohm input lead with coax connector for the output. The info says: typical VHF gain of 25db and UHF gain of 20db with 10db adjustment range, switchable FM trap and short-circuit protection.

The oudoor part, which looks like a balun molded over with vinyl is, in fact, a preamplifier.

FWIW, while the 15-1108 is a lousy pre-amp, the indoor section (without the mast-mounted module) makes a decent (enough) booster for use as a distribution amp.