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Discussion Starter · #21 ·
Thanks guys, couldn't find the RCA locally yesterday, but should I disconnect the preamp on the 4228 and replace with with either the RCA or 7777 on the downlead? I have a power source about 35' downline from the antenna, is that OK to amp it halfway from the TV, or should I just run the amp right before the tuners inside the house? In rabbit's diagram, it looks like the preamp precedes even the coax after antenna, so does that mean I should mount the preamp on the antenna mast, and just run the power inline downstream, by the tuner? If I take out the preamp on the 4228, will I need something else other than just the RCA? I guess the linear logic is escaping me. I'm contemplating getting the hi VHF antenna and just mounting it above the 4228, looks like I could use the dual inputs(VHF and 4228) to the RCA, and combine to Coax, to the power unit then to the tuner. Does this work?
 

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should I disconnect the preamp on the 4228 and replace with with either the RCA or 7777 on the downlead?
Yes, 7777 or the 7778 if you think the 7777 might overload as Calaveras said.

The 7778 and the RCA TVPRAMP1R have about the same gain. The 7778 has an all-channel input. If you use a UHF and a VHF antenna you must combine them with a UVSJ before the 7778. The RCA is less expensive, has a history of quality control problems, and has separate inputs for VHF and UHF antennas.

The best place for the preamp is near the antenna. The power inserter and power supply go inside near an AC outlet.

The coax between the preamp and the power inserter inside does two jobs. It sends the DC power for the preamp up the coax and it also sends the signals down the same coax to the TV.

There are special circuits inside the preamp and power inserter that are designed to allow the DC power and the TV signals to share the same coax. There is no need for a separate power line for the preamp, and there is no need for AC power near the preamp. That is the way a preamp is designed, with one unit outside and one inside.
http://downloads.channelmaster.com/Sheets/7777_7778_UG.pdf



RCA manual:
http://voxrightnow.custhelp.com/app...lling-the-rca-tvpramp1r-outdoor-pre-amplifier

If I take out the preamp on the 4228, will I need something else other than just the RCA?
For whichever preamp you use, you will need the preamp near the antenna and its power unit inside.
I'm contemplating getting the hi VHF antenna and just mounting it above the 4228, looks like I could use the dual inputs(VHF and 4228) to the RCA
Correct, the RCA has a separate input for each antenna. The combined/separate switch should be set to separate. If the switch acts up, set it to combined and use a UVSJ UHF-VHF combiner to combine the two antennas before the preamp.

A distribution amplifier, to make signals stronger for splitting if needed, is designed to be used inside near AC power.
 

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If the antenna is outside the coax shield should be grounded with a grounding block that is connected to the house electrical system ground with 10 gauge copper wire for electrical safety and to reject interference. For further compliance with the electrical code (NEC), the mast should also be grounded in a similar manner to drain any buildup of static charge, but the system will not survive a direct strike.

 

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Discussion Starter · #24 ·
Thanks Rabbit, those diagrams really help to visualize what I need. I don't have anything nearby the antenna to ground the mast with, other than roof flashing.

I think I will try a straight run with coax from the preamp (once I get it) to the 4228 to see if I even get channels, then will see if I need filters and the hi VHF. Will the 4228 not pull hi range VHF at all? Should I just order the suggested Hi VHF now, or wait for the preamp to check first. . . ?

Also, would this be an appropriate distribution amp, or should I get a CM variety?

Cheers,
Joel
 

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Your 4228 is the old model that, even though it is a UHF antenna, picks up some VHF-High signals better than the new 4221HD. I think it would be useful to find out what it can do with your VHF signals with a preamp to make a comparison with the VHF antenna that will be added later. See curve AA in attachment.

Also, would this be an appropriate distribution amp, or should I get a CM variety?
I'm not impressed with that distribution amp. Do you already have it? What is the model number? How much dB gain does it have? What is the Noise Figure? That looks like the GE AV93290 4-WAY DISTRIBUTION AMPLIFIER.

I prefer the Channel Master 3412, 3414 and 3418 series.

You don't know yet if you will need to use a distribution amp instead of a passive splitter. How many ways do you need to split the signals?

I don't have anything nearby the antenna to ground the mast with, other than roof flashing.
That would not satisfy the requirements of the NEC electrical code. The coax should be grounded with a grounding block connected to the house electrical system ground with 10 gauge copper wire. The mast should also be connected to the house electrical system ground with another 10 gauge copper wire.

Many people put up an outside antenna without grounding the coax shield or the mast, but I am obligated to tell you the way that is required by the code and local electrical regulations.

Satellite System Grounding
Part 2 - NEC Overview
Presented by Todd Humphrey
http://www.dbsinstall.com/diy/Grounding-2.asp

Todd Humphrey doesn't speak for the NFPA that publishes the NEC code, but he has some ideas that are helpful. The local electrical inspector has the final say if you are willing to get him involved. Some inspectors are more friendly than others; a local electrician could tell you.

There is a grounding thread if you want to learn more or ask more questions about grounding.
LINK:
http://www.avsforum.com/forum/25-hdtv-technical/1704881-grounding-antenna-masts-coax-cable.html

I think it is important to at least ground the coax shield to the house electrical system ground with a grounding block for personal electrical safety. I have had three close calls with electrical shock.
 

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BTW: Mast-Mounted Preamp has plenty of Gain to drive long Coax runs plus Loss in RF Splitters to many drops....ADDING a Distribution Amplifier is NOT usually needed and the extra Gain can Overload the TV Tuners.

Geezzz.....the OP already has a TOP-OF-THE-LINE CM4228 UHF Antenna with more UHF Gain than HD-7697 or HD-7698, so OP ONLY NEEDS to add a $20 Hi-VHF Antenna and replace the Preamp. Also note that Hi-VHF stations are 40-deg away from San Diego's UHF stations, so Combo would need to swing back and forth on a Rotator....

Ch8 and Ch10 are listed with NM of 23-24 dB (low but doable), but are both 2Edge (which typically reduces reliability). Which means they're going to be VERY Iffy with CM4228, which has "some" Hi-VHF Gain, but it varies quite a bit across Hi-VHF Band...and the Hi-VHF SWR is very excessive which can degrade performance not only due to SWR Nulls, but also by the signals bouncing up and down the Coax, forming short-delay Multipath (per the late Dr O. Bendov papers re EVM, Error Vector Magnitude degradation ) that the Tuner's Equalizer was never designed to accommodate....so using CM4228 is unlikely to provide long-term Reliability in OP's Location....I only recommend it for Hi-VHF Band in STRONG signal areas:
http://imageevent.com/holl_ands/multibay/8bayrefl/oldcm4228wrefl

Note that measurements on my son's CM4228 indicated a fairly NARROW Gain Hole on Ch11, whereas Ken Nist's HDTV Primer showed LARGE CHANGES in Gain across Ch8 and across Ch10, which would make it very difficult to receive those ATSC waveforms:
http://www.hdtvprimer.com/antennas/comparing.html
Since the dimensions are DIFFERENT, I suspect that Ken Nist measured an EARLIER CM4228 variation....as is a common reality in the ever changing search for lower cost suppliers....and OP may have one or the other...or perhaps a slightly different THIRD variation of the "CM4228" that we haven't modeled yet....I included 4nec2 Files containing detailed Dimensions for both variations....but Ken Nist's will be very difficult to "see" without using a 4nec2 File Viewer.

PS: I developed the HHH (Holl_ands Horizontal Harness) modification to CM4228 to not only improve the UHF Frequency Response...esp on Ch18/19 here in San Diego...which also improved Hi-VHF Frequency Response and reduced the Hi-VHF SWR from Excessive to "just" a bit HIGH:
http://imageevent.com/holl_ands/multibay/8bayrefl/oldcm4228withhollandshorizharness [Use ALT #1 .]
Hmmmm....I really should extract JUST the drawing for the HHH and add Dimensions....just as I did for newer CM4228HD's HHH....
 
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Antenna Mast and Coax Grounding Summary (if you are Lucky):
Your house is no doubt wired for Cable and will already have a GROUNDING BLOCK at the Cable Entry Panel (usually accessed from Exterior of house). If you trace its Ground Wire (usually Green or Bare Copper) you should find that it is connected to "Ground" at the AC Power Breaker Box. If you can run the OTA Coax close to that point, use another Ground Block (or upgrade existing to a DOUBLE) and connect same place as the other. ALSO run a Ground Wire from bottom of Mast to the same connection point.

In case of a direct lightning hit, the Ground Wires form a preferred path to Earth...so MINIMIZE the wiring length actually INSIDE the House (which could become ionized plasma)....and Coax Ground Block is supposed to be AT the House Entry Point.

It's more difficult if you elect to have a Coax Entry Point at some OTHER location....as discussed in the above referenced documents.

Another reason for Coax Grounding Block: Strong Winds blowing across Antenna (and Mast) cause Static Electricity Buildup, which is hopefully dissipated by the Grounding Block before it ZAPPZZZ your equipment...
 

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Discussion Starter · #28 ·
Just a thought: should I replace the balun, and should I be concerned about corrosion on the 4228? Its has sat in weather for about a year. I'm going to try to get the RCA preamp today, and install on Thurs, and will order the Hi VHF antenna as well, is it OK to try to just mount on top of the 4228? I may need to extend the pole a bit (and will reduce the WAF factor considerably. . . )
 

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Yes, the Balun is subject to degradation due to moisture seepage and SHOULD be replaced by an OUTDOOR rated Balun (300-ohm leads have DC connection to 75-ohm shield to drain off Static Electricity Buildup). New ones typically have a significantly lower Insertion Loss than old devices anyway. FYI: Philips Balun had the lowest Insertion Loss (0.5 dB) measurement (maybe Lowes or Sears or on-line from Summit Source et.al)...and the Channel Master Balun is nearly as good (abt 1 dB). ADTech measured higher Loss in W-G, Eagle, Magnavox and ONE of their (A-D) Baluns....and that's about all I've ever seen.... Loss measurements I did more than 10-years ago are no longer of any value...but I would still avoid most Home Depot types....and R-S.

It might also be worth buying a long length of RG-6 Coax (from R-S or Fry's is just fine) and temporarily run it from Antenna to location of your HDTV. Compare to existing to see if it also needs to be replaced....but first try cutting off as much of the Coax as is feasible on the roof (perhaps back to a location under the eaves to protect the new splice as best as possible) and insert a NEW piece of RG-6....if there has been moisture seepage into the Coax, hopefully it was contained to just the upper parts and you won't have to tackle the probably more difficult interior replacement.

To prevent degradation of F/B Ratio, there SHOULD be at least 4-ft Separation (Metal-to-Metal) between the Antennas....but Gain isn't affected until Separation is as close as 1-ft....do what you can. Most people put Hi-VHF Antenna below UHF (not ideal, but Hi-VHF Antenna could be fairly close to the roof). CM4228 would benefit from the extra height....but if you insist you could place it on the bottom and see how it works....
 

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Discussion Starter · #30 ·
Just to follow up, today I ran a new run of coax, and attached the RCA Preamp to the 4228. Awesome, got just about every channel (KUSI is a bit shakey, and the CW is not present), but everything else comes in great, even several LA stations (the 4228 is facing south). The Hi VFH antenna is due to arrive Tuesday, I may not even put it up.

As a bonus, after connecting the new run coax and getting good signal strength, I connected the old run of coax, and it works too :)

Just connected my Roamio OTA, and things are looking good, but now I'm torn between getting a Tivo Mino to use with the Roamio, or just Change over to HDHR OTA's in MCE.

thanks all for the help, Hollands you were right, the 4228 worked, I just needed a new preamp, so thanks. :)

Cheers,
Joel
 

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I'm surprised you get FOX on Ch19, but not KUSI on adjacent Ch18 (I think they share the same Antenna). You might want to try moving the CM4228 up and down 6-12 inches, if you can. Personally, I don't see anything on their schedule that I would consider a "Must Have":
http://www.locatetv.com/listings/kusidt-kusi-dt#07-Nov-2015
LocateTV also shows other channels via pull-down menu selector.....

The CW on Ch23 is located in Tijuana....further away and a somewhat different direction....at the BOTTOM of the TVFool, so it's NOT going to come in from your location. But you probably COULD receive The CW on Ch31 located on Mt Wilson (L.A.).....which would require a Rotator (or a second UHF Antenna) for those rare occasions you WANT to watch their (I think) superlative shows:
http://www.cwtv.com/shows

Since you don't NEED the 8-El Yagi for Ch8/10 reception (CM4228 surprises us yet again)....you might want to point it to the NORTH to receive LA Traffic Reports (ABC on Ch7 & FOX on Ch11) and esp. KCAL on Ch9 which carries many L.A. Sports programs:
http://losangeles.cbslocal.com/category/sports

You should also be able to pick up MY NETWORK (MyN) on Ch13, that has a number of shows that might be of interest:
https://www.mynetworktv.com
http://www.foxla.com/my13
 

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Discussion Starter · #32 ·
Thanks Hollands, I'll check them out, I will be getting the Yagi tomorrow, I may throw it in a few different directions just to see what I can get. . .
 

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Discussion Starter · #33 ·
As an update, I had signal loss and pixellation on the Charger game last Monday night, so I'm headed up to put up the hi-gain VHF antenna. I'm going to try first on the same mast as the 4228, any suggestions? I think it needs to be pointed at 180, the same as the UHF. Will report back, but any suggestions welcome. It will go into the RCA amp up there. . .
 

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Discussion Starter · #34 ·
went up to the roof, but need additional mast, I do have the mast mount for my Voom dish that i just removed, if the VHF is in front of the UHF (about 6 ft away), but connected to the same preamp on the UHF mast, will that cause problems? My two easiest options are to double the height of the existing antenna mast, or to place the VHF antenna on the Voom mast, which is at the pinnacle of the roof line, and more-or-less directly inline with the UHF antenna.

Thanx for any opinion,

Joel
 

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You need AT LEAST 4-ft (8-ft even better) HEIGHT difference to make sure that signals are minimally affected by one Antenna being in FRONT of the other [which is what I THINK you are describing].

However, this wouldn't be a problem is you can ensure that the Antennas are pointed in DIFFERENT directions so that one doesn't "Look" thru the other....perhaps this would involve reversing the Antenna mounts???

You might also want to consider mounting one Antenna above the other....which I modeled and found that Gain isn't noticeably affected until the Metal-to-Metal separation was about 1-ft.....although maintaining excellent F/B & F/R Ratio performance required AT LEAST 4-ft (8-ft even better) HEIGHT difference.
 

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Discussion Starter · #36 ·
OK, thanks, local HD and Lowes are out of the 5 ft. masts, I may order a 10 footer but WAF will decline immensely at that height. . . will try first with a 5 ft. and check results. The Hi VHF I got from MCM had a dreadful diagram and no instructions, not sure if I built it properly. . .
 

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The Hi VHF I got from MCM had a dreadful diagram and no instructions, not sure if I built it properly. . .
Yeah, that's assembled wrong.

Go here (http://www.mcmelectronics.com/product/STELLAR-LABS-30-2475-/30-2475) and zoom in on the photo to see how it goes together. Ah, hell. Better yet, call them up and make them support the cheap Chinese crap they're selling. You can also download the "manual" from their website.
 

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Discussion Starter · #38 ·
yeah, the quality does seem quite crappy, which I guess is consistent with the cheap price, but if it works, I'm good. None of the wingnuts and bolts seem to match quite as they were intended, I'll try to zoomed pic version later, thanks for the suggestion. . .
 

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I just recently bought one of these. I'll try to take some pictures shortly to show correct assembly for you. FWIW it seems to work very well so far. I'm picking up an ABC affiliate 73 miles away with it sitting on the couch back in my living room (no preamp, 25ft of rg6 connected to my TiVo OTA) I'm waiting on the holiday break to join it with my uhf antenna on the mast outdoors
 
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