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The Official AVS Antenna and Related Hardware Topic! - Page 527

post #15781 of 16013
Quote:
Originally Posted by ctdish View Post

Be careful that the power doesn't have to go through any splitters. They are frequently DC shorts.
John

Well, we'd like them to be a series short if we want DC pass through but not a shunt short.

Most commonly, splitters, unless otherwise marked, will be DC blocking.
post #15782 of 16013
I tested a few of various ages and manufactures that I have here and I was wrong. None of them were DC shorts shield to center and they were very low resistance between any of the center conductors so you could pass power through then OK. The risk would be that that TVs connected to the other ports would have DC on the tuner input.
John
post #15783 of 16013
Quote:
Originally Posted by ctdish View Post

Be careful that the power doesn't have to go through any splitters. They are frequently DC shorts.
John

No Splitter in between, just a straigt shot from the power inserter to the amp

Quote:
Originally Posted by ADTech View Post

Sounds like a short circuit between the shield and the center conductor on one of the cables.

Swap out each existing cable run with a pre-made cable for troubleshooting purposes.

or... If you have an ohmmeter, unplug both ends of each cable and check for a center-to-shield short circuit. Then, install a jumper at one end of the cable between the shield and center conductor, then go to the other end and look for a low resistance (several ohms, depends on physical length) between the center and shield. These tests will check for gross failures (opens/shorts) in the coax.

I've traded out/removed all other cables that I though might be causing the problem. There is one cable I did not think to disconnect and that was the one from the amp (the one i'm using has 2 outputs) to the bedroom. I figured since this line was working it was all good but I'll give that a try when I get home.

I do have a cheap harbor freight multimeter that I could use to test the cable itself. I did a little research and it sounds pretty straight forward.


Thanks again for the input, I'll let you know how it turns out.
post #15784 of 16013
I recently moved to a house in Christiansburg VA from Blacksburg VA and while the TV reception is MUCH better than what I could pull in before, I would like to try and get WSET. I feel like my location might make this possible. (top of a hill, no major obstructions), Right now I have an antennasdirect DB2 in the attic for the bedroom tv and a loop/dipole antenna for the ground floor tv sitting next to the tv. I figure I'll probably have to mount something on the roof but I'm not sure how big of an antenna I'll need to get WSET.

http://www.tvfool.com/?option=com_wrapper&Itemid=29&q=id%3d5b94c8eaad9a8f

In the local thread, others seemed to think I could pick up WSET with the right antenna and they referred me to this thread.

I've been looking at the RCA/Audiovox ANT751R but it is rated for 'up to 40mi' which would put me right on the edge of getting WSET.
post #15785 of 16013
Quote:
Originally Posted by Prototype3a View Post

In the local thread, others seemed to think I could pick up WSET with the right antenna and they referred me to this thread.

I've been looking at the RCA/Audiovox ANT751R but it is rated for 'up to 40mi' which would put me right on the edge of getting WSET.

Antenna ratings in miles is marketing and reception has more to do with the location of the transmitter and receiver. I see WSET is 2 edge so I clicked on the call sign in TVFool to see what the path looked like. You have a big mountain to cross over which is not really good. OTOH it's on RF 13 which does a better job getting over mountains than UHF does. I wouldn't skimp on the antenna. I'd go with the Winegard HD7698P or the Antennacraft HBU55. A preamp might get overloaded since you have a number of very strong local stations. You might be better off to keep the coax run short and use RG-11 instead of a preamp.

I see your PBS station is on RF 3. That's unfortunate. Neither antenna above covers low VHF but it's a very strong signal so they might work anyway. I have a nearby low power station on RF 3 and I receive it fine on a high VHF antenna.

Assuming you can receive WSET it's likely to have times when it drops out due to atmospheric conditions over the 2 edge path.
post #15786 of 16013
I get the RF3 PBS station with both the DB2 and the bunny ears in the living room just fine so I suspect anything the same size or bigger would pick it up on the roof just fine. As I said before, I'm really only concerned about WSET. I hadn't considered the possibility of overgaining the tvs but I also wasn't planning on installing an amp. Seems like I need to do some research on how to secure a huge antenna to my roof.
post #15787 of 16013
I mounted mine on the end of the peak with some home-made brackets.

mount2small.JPG 378k .JPG file
post #15788 of 16013
Hello all!
I'm looking to change over from comcast cable to OTA! Here is my TV Fool info:

http://www.tvfool.com/?option=com_wrapper&Itemid=29&q=id%3d5b94393a58a8bb

I'm new at this since I've used cable all my life. Comcast is encrypting the channels starting March 1st. I'm only interested in the top 8 channels in the right hand chart which are the network channels. It would seem I need two antennas, one for the 90 degree area and another for the 0 degree area. Also I have looked at this antenna:

http://store.gomohu.com/sky-hdtv-outdoor-antenna.html

Is this product any better than others?

Thanks
post #15789 of 16013
You have sort of medium strength signals with WHAS and WBNA being high VHF so I would not recommend any small non traditional antennas. I would try an HD7695 shown here:
http://www.summitsource.com/winegard-hd7695p-high-definition-vhfuhf-hd769-series-antenna-element-local-hdtv-digital-signal-channel-outdoor-television-aerial-coax-with-gold-connectors-zone-part-hd7695p-p-6788.html?ref=1&gclid=CPu-172LkrwCFaHm7AodVjsAsQ
You may have trouble with the top two stations without a rotator but you could try without one and see what happens.
John
post #15790 of 16013
Quote:
Originally Posted by williammanda View Post

Hello all!
I'm looking to change over from comcast cable to OTA! Here is my TV Fool info:

http://www.tvfool.com/?option=com_wrapper&Itemid=29&q=id%3d5b94393a58a8bb

I'm new at this since I've used cable all my life. Comcast is encrypting the channels starting March 1st. I'm only interested in the top 8 channels in the right hand chart which are the network channels. It would seem I need two antennas, one for the 90 degree area and another for the 0 degree area. Also I have looked at this antenna:

Looks like your main transmitter site is where all those stations at 47 miles and 4-5 degrees are. They are all 2 edge which means two mountains to refract over. The good news is I don't see any major mountains to cross.

Quote:
http://store.gomohu.com/sky-hdtv-outdoor-antenna.html

Is this product any better than others?

That's not going to work except for your top 2 stations.

You need a serious outdoor antenna. I wouldn't even try anything less than the Winegard HD7698P or the Antennacraft HBU55. The antenna needs to clear all the local obstructions like buildings and trees. A moderate gain preamp like the Winegard LNA-200 would be helpful and probably not get overloaded by the very strong WKZT because you're not pointed at it. Even if you receive all the stations it's very likely that some will have dropouts under certain weather conditions. Distant 2 edge paths are often unstable.
Edited by Calaveras - 1/22/14 at 5:33pm
post #15791 of 16013
I would also check out the Louisville HDTV thread. There are probably folks from around Elizabethtown and Hardin County that are reliably getting OTA TV from Louisville. (Yes, I'm originally from Louisville. biggrin.gif )
post #15792 of 16013
Looking for an opinion on my issue. I can't seem to get Fox in HD to come in at all, the station just isn't there when i search for it. I'm located in Astoria Queens, less than 5 miles from the empire state building (which i think is the broadcast source). I'm using a mohu leaf (amplified version) giong to an iview3500stbii box with hdmi out to my receiver. I get plenty of other HD stations and I also get fox in SD (5-3), any ideas on why this isn't coming in? I checked and i have the most up to date firmware on the tuber box.

Is a different antenna needed?
post #15793 of 16013
Quote:
Originally Posted by DDLOP View Post

Looking for an opinion on my issue. I can't seem to get Fox in HD to come in at all, the station just isn't there when i search for it. I'm located in Astoria Queens, less than 5 miles from the empire state building (which i think is the broadcast source). I'm using a mohu leaf (amplified version) giong to an iview3500stbii box with hdmi out to my receiver. I get plenty of other HD stations and I also get fox in SD (5-3), any ideas on why this isn't coming in? I checked and i have the most up to date firmware on the tuber box.

Is a different antenna needed?
Try punching in 44.1 on your receiver and turning the mohu a little in each direction and, up and down. There doesn't seem an obvious reason why you are not getting WNYW, while you are clearly getting WWOR's signal. WNYW's Fox HD is on channel 44, while the SD is on WWOR's 38.. Work with it a little , and report back if you have no good results.
post #15794 of 16013
www.rabbitears.info shows FOX HD on 44.3...try punching that in directly.
Did you check iview threads to see if anyone else was having problems decoding FOX broadcasts....I though that was a FOX network transmit PSIP problem that was solved many years ago....
post #15795 of 16013
Need some antenna advice. I am 10 mi or less from all of the transmitters I care about with all of them included in about a 10 degree subtended angle. My TVFool report:

http://www.tvfool.com/?option=com_wrapper&Itemid=29&q=id%3d5b9415ace426cc

I need an indoor solution and I am using a Tivo Roamio, which I seems to have significant issues with multipath relative to my TV tuners. I tried a Winegard Flatwave, but get periodic dropouts on various channels. Tivo indicates signal strength of 60-70 with SNR of about 25 dB.

I borrowed an old RS dual bow tie and have much better results - SNR improved 2-3 dB and the dropouts are very infrequent.

The questions is what to purchase (since the RS antenna is long discontinued). I find a few available candidates:
Clearstream 2 or 2V
Clearstream 1
Clearstream Micron R
Channel Master 4220 2 bay bowtie
Terk HDTVa (don't need the amp but I think it can be turned off)

One of my primary networks is on RF channel 11, so I am a little concerned about how the currently available antennas will deal with that versus the borrowed RS. My thought is the CS 2V or the Terk are not the answer with their VHF dipoles/rabbit ears since it might make the multi path worse. I also don't know if the UHF-only products might be better tuned and have less VHF sensitivity than the old RS.

Opinions/recommendations?

Keith
post #15796 of 16013
A-D Antennas using a Printed Circuit Board (PCB) type Balun severely attenuate VHF signals, so CS-1, CS-2 and Micron R are poor choices for Ch11 reception. The CS-2V has a separate VHF Dipole. But in UHF Band CS-2V and similar CM-4220 are fairly Directional...so you LIKELY will have to ROTATE them to receive signals from other than stations towards 100-deg azimuth.

I would start with the UNAMPLIFIED Terk HDTVi which has an irregular, multi-directional Antenna Pattern that MIGHT find a sweet spot for rejecting Multipath.

You also might have success with a Bi-Directional Hi-VHF + UHF Antenna that has Nulls towards the sides to suppress Multipath....if you can find a sweet spot. Bi-directional Antennas include simple Rabbit-Ears/Loop and 2-Bay's with NO Reflector, such as Mohu Leaf, WallTenna or a simple DIY Project:
http://gomohu.com
http://www.walltenna.com
http://imageevent.com/holl_ands/multibay/uhf2bays/uhfm2

Due to your VERY Strong signal levels, do NOT use an Amplified Antenna.
post #15797 of 16013
Quote:
Originally Posted by DDLOP View Post

I'm using a mohu leaf (amplified version) giong to an iview3500stbii box with hdmi out to my receiver.

You should not be using an amplified antenna 5 miles from the transmitters. The signals are very strong and you may be getting overload.
post #15798 of 16013

Calaveras:

 

I am used to combining antennas with stacking bars. However, some recent antennas now have a black boxes and no longer have lead in terminals where you could connect the bars.

 

I wanted to combine 2 UHF antennas together using a splitter backwards ,after reading this suggestion on the forums.

 

I was curious, if I go ahead and do this, what is the signal loss for

 

1.) Antenna's pointing in the same direction

 

2.) Antenna's pointing in different directions

 

Does the gain from combining 2 antennas together outweigh the loss? Thanks...

post #15799 of 16013
Quote:
Originally Posted by ddm237 View Post

Calaveras:

I am used to combining antennas with stacking bars. However, some recent antennas now have a black boxes and no longer have lead in terminals where you could connect the bars.

I wanted to combine 2 UHF antennas together using a splitter backwards ,after reading this suggestion on the forums.

I answered your PM but for others I'll add something here.

Quote:
I was curious, if I go ahead and do this, what is the signal loss for

1.) Antenna's pointing in the same direction

Let's say the splitter has 3.5 dB loss when used as a splitter. Ignoring all other losses, when used as a combiner the loss will be 0.5 dB. Instead of getting 3 dB gain from 2 antennas you'll only get 2.5 dB.

Quote:
2.) Antenna's pointing in different directions

When combining antennas that are out of phase, the splitter acts like it always does, giving you 3.5 dB loss.

You don't want to combine two antennas pointed in different directions with a simple combiner in most cases. Two antennas on the same mast pointed in different directions will produce a complex situation depending on where they are pointed. Some signals may have in phase components and the signals will add. Some may have out of phase components and subtract or interfere with each other.

Quote:
Does the gain from combining 2 antennas together outweigh the loss? Thanks...

If you pay attention to the components you can expect to get about 2.5 dB by stacking two antennas. If you're less careful you could end up with 1.5 dB.

Chuck
post #15800 of 16013
When pointing in SAME direction, internal component Loss in the Combiner is AT LEAST 0.5 dB. The 3 dB Combining Gain due to the internal Hybrid Transformer is ONLY reached when the Amplitude and Phase of the two signals are MATCHED. Antenna Mis-match, INCLUDING mismatch due to signal reception differences between the two Antennas (i.e. Multipath and nearby object perturbations) will subtract from the 2.5 dB Combining Gain mentioned above.

Fortunately, there is a MUCH LARGER amount of Space Diversity Combining Gain potentially available, as one of the Antennas experiences a Multipath Fade event while the other continues to receive a signal (with 3.5 dB Combining Loss). Of course if BOTH experience a significant Fade, there will be a (hopefully brief) signal dropout that may or may not be recoverable via the ATSC's built-in Error Detection and Correction Code:
http://www.hdtvprimer.com/antennas/siting.html
http://www.antenna-theory.com/arrays/diversity.php
http://www.comm.utoronto.ca/~rsadve/Notes/DiversityReceive.pdf [Passive Combiner would be an "Equal Gain" type.]

Even more detailed info:
http://www.eecs.berkeley.edu/~dtse/epfl02.pdf
and
http://www.utexas.edu/research/mopro/papercopy/chapter06.pdf [esp. see Fig 6-7 and 6-8]
From http://descanso.jpl.nasa.gov/Propagation/1274/1274toc.cfm
Sorry, I no longer have space separation statistics handy for VHF & UHF frequency bands....

This helps to explain the robust performance of Antennas with Stacked Elements, such as Multi-Bay Bowties, Grey-Hoverman, etc.
Edited by holl_ands - 1/27/14 at 4:09pm
post #15801 of 16013
"Multipath" is a term I often seen tossed around as a doom and gloom killer of OTA reception. Can someone please explain in layman's terms exactly what affect multipath has on reception of digital TV signals? In the olden, analog days, ghosting, sometimes unwatchably bad, was the affect I saw from multipath. An antenna in my attic, surrounded by metal ducting and vent pipes, gave horrible ghosting back in the day. Now, I get crystal clear HD from all ten local stations (and their many sub-channels). I'm sure that multipath is still present but I have never seen any impact from it since the conversion to digital.
post #15802 of 16013
Quote:
Originally Posted by A J View Post

"Multipath" is a term I often seen tossed around as a doom and gloom killer of OTA reception. Can someone please explain in layman's terms exactly what affect multipath has on reception of digital TV signals? In the olden, analog days, ghosting, sometimes unwatchably bad, was the affect I saw from multipath. An antenna in my attic, surrounded by metal ducting and vent pipes, gave horrible ghosting back in the day. Now, I get crystal clear HD from all ten local stations (and their many sub-channels). I'm sure that multipath is still present but I have never seen any impact from it since the conversion to digital.

Consider yourself lucky if you've never had any dropouts. Multipath that can't be corrected by the tuner equalizer effectively acts like noise to lower the signal-to-noise ratio. As long as the SNR doesn't drop below 15.2 dB (ideally) you'll have perfect reception.

You're experiencing the upside of the DTV conversion like I am here. Analog reception was sort of ghosty, watchable but not that great. After the conversion I found that all the stations had high enough SNRs to be receivable. Some people experienced the downside. Their pictures were so bad that after the conversion the SNRs were too low and they received nothing.
post #15803 of 16013
Quote:
Originally Posted by A J View Post

"Multipath" is a term I often seen tossed around as a doom and gloom killer of OTA reception. Can someone please explain in layman's terms exactly what affect multipath has on reception of digital TV signals? In the olden, analog days, ghosting, sometimes unwatchably bad, was the affect I saw from multipath. An antenna in my attic, surrounded by metal ducting and vent pipes, gave horrible ghosting back in the day. Now, I get crystal clear HD from all ten local stations (and their many sub-channels). I'm sure that multipath is still present but I have never seen any impact from it since the conversion to digital.
You probably had the worst ghosting from WSOC and WCCB at your location. Now with digital, multipath can confuse the tuner and prevent it from decoding the signal. Instead of ghosting, you get no picture at all. Fortunately with a change in their digital transmitting antennas and power levels, you no longer seem to have a problem with multipath at your location. And the type of receiving antenna you use can reduce multipath as well.
post #15804 of 16013
Here's a page that includes a formula useful for determining spacing for long yagi type antennas:

http://www.dxzone.com/cgi-bin/dir/jump2.cgi?ID=13265

I used the plots on the DTV Primer page for the 91XG to determine the beamwidth.

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

Turns out that for the 91XG with increasing gain with frequency, the spacing stays about the same across the UHF band. I calculated around 32".
post #15805 of 16013
Quote:
Originally Posted by A J View Post

"Multipath" is a term I often seen tossed around as a doom and gloom killer of OTA reception. Can someone please explain in layman's terms exactly what affect multipath has on reception of digital TV signals? In the olden, analog days, ghosting, sometimes unwatchably bad, was the affect I saw from multipath. An antenna in my attic, surrounded by metal ducting and vent pipes, gave horrible ghosting back in the day. Now, I get crystal clear HD from all ten local stations (and their many sub-channels). I'm sure that multipath is still present but I have never seen any impact from it since the conversion to digital.
ATSC uses a complex digital waveform, where the SYMBOL Rate is 10.76 Mbaud, with 3 bits/symbol (i.e. 3 bits/baud) that's 32.28 Mbps, which yields 19.39 Mbps of usable data after processing the Error Detection and Correction Codes:
http://en.wikipedia.org/wiki/8VSB

Multipath is caused by constructive and destructive interference between (usually) Direct Path and one or more Reflective Path signals:
http://en.wikipedia.org/wiki/Intersymbol_interference
http://www.hdtvprimer.com/antennas/siting.html

At 10.76 Mbaud, each SYMBOL is only 93 microseconds long. So ADJACENT Symbols are smeared together with "typical" Multipath Delays of 3-10+ microseconds. Gen 5+ ATSC chips are capable of successfully processing up to +/- 50 microseconds of Multipath Delay, but only if it's weaker interference. If Multipath falls within the Envelope of Performance for the ATSC chips Adaptive Equalizer, errors are minimized and in some conditions can work a bit BETTER than a single fading path signal. The PROBLEMS occur when Multipath signals are rapidly fading (e.g. reflections off of fast moving cars, trucks & airplanes) OR have long delay signals of roughly equal signal strengths (e.g. Bridges & Skyscrapers) OR have VERY short delay with nearly equal signal strengths (e.g. inside attics or antenna located among rather than above surrounding buildings). ATSC A/74 contains RECOMMENDED Adaptive Equalizer Envelope of Performance Curves and a set of 50 actual OTA captures of absolute worst case test locations, most of which were REQUIRED to be successfully received by CECB (Coupon Converter Boxes), so post-2007 ATSC chips provide very robust reception in Multipath.

In many cases the solution to Multipath problems is Antenna Location, Location, Location.....
Edited by holl_ands - 1/28/14 at 1:24pm
post #15806 of 16013
I'm looking for suggestions on an in-attic antenna. I can pull everything I need with an indoor antenna but I have to move the antenna when I switch channels - which gets old after a while.

I've read both my local forum (and posted there) and many posts on in this thread. Sounds like the recent Antennas Direct antenna's are designed with compromises for retail/shipping and not necessarily for picking up high VHF stations. I have two high VHF's in my area (7 & 8) - here's my tvfool data:
http://www.tvfool.com/?option=com_wrapper&Itemid=29&q=id%3D5b94693d46183e
post #15807 of 16013
^^^

I don't think having to move your antenna for every station would be acceptable to most people. There's no guarantee that you won't run into the same problem in the attic. There's no magic antenna that's guaranteed not to have the problem in the attic. No one here can tell which antenna if any will work. It's pretty much luck of the draw. An outdoor antenna would be much better especially with those 2 edge stations you have. If you're determined to use an attic antenna then buy something that covers VHF and UHF and make sure you can return it if it doesn't work. If you're lucky you'll find an antenna and a place to put it that receives all the stations at the same time.
post #15808 of 16013
Although the above is true, you would have a good chance of receiving the stations between 150 and 160 deg azmiuth using an antenna like http://www.solidsignal.com/pview.asp?mc=03&p=HBU33&d=AntennaCraft-33-Element-UHF--HighBand-VHF-Outdoor-HDTV-Antenna-%28HBU33%29&c=TV%20Antennas&sku=1607900500
You would likely not need to move the antenna unless you wished to receive stations from other directions.
John
post #15809 of 16013
This is along the lines of what I was thinking or the smaller, cheaper http://www.amazon.com/AntennaCraft-HBU22-Boom-Antenna-High-Band/dp/B0035A6AUG/ref=sr_1_6?s=audio-video-accessories&ie=UTF8&qid=1391021459&sr=1-6. To help that theory, the attic faces south and juts out a little bit in front of the house (over the garage).

ABC is not necessarily in the same direction, however, I may be able to pick of the one that is in the same direction (WOTV) or put a smaller UHF antenna on the north side of the house. However, IIRC, combining signals can be troublesome...

Not sure if this helps - the times I have to move/mess with the indoor antenna the most is with CBS and NBC (VHF). I also tend to get better results if I turn off the built in amplifier for NBC and turn it on for CBS.
post #15810 of 16013
For a UHF antenna, the 43XG from Antennas Direct is often overlooked in favor of the longer 91XG version. But if a smaller size is needed, the 43XG is still a strong performer. I am now having good luck with a 43XG and a Kitztech 100 preamp, receiving channels from 75 miles, as well as local VHF. So a very good antenna to consider if UHF is needed.
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