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Channel Master and Winegard antenna amps for UHF only are Titan #7775 and Winegard #4700/4800. Titan #7777 is a VHF/UHF amp, which will not optimize UHF performance.
 

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That is incorrect...


The 7777 has UHF and VHF inputs. The 7775 only has UHF. However, they both have the same specs on UHF. They both have 26db gain and a noise figure of 2db.


So, the 7777 will optimize UHF performance


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Quote:
Originally posted by Tom Harms:
You are correct that the gain is the same, but the 7775 will not pass VHF to the receiver.
Could you please explain what impact this would have on a UHF only antenna and a UHF/VHF antenna? It seems that the 7777 is a better deal and that there are no advantages of the 7775. Am I missing something? Thanks.


Jay
 

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Regarding preamps you can't always believe the specs. I have both a Titan and a Winegard. They are very similar but the Channel Master Titan has better specs. The Winegard however works better for me. Both are very good though.


As to UHF only or VHF: I should think most people in general would want to have separate antennas and amplifiers. The antennas should be separate for multipath. The amps should be separate because often there is a strong VHF channel that can overload a combo unit, and a UHF only one works. Of course it all depends on your channel mix, transmitter powers, distance, etc. but UHF weakens more with distance and obstructions. I can boost to the max my UHF, but VHF I can't, due to strong VHF and also strong FM (that the FM filter on the preamps can't filter enough).
 

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jhe,


Thanks for the reply. Here is a portion of the spec for the 7777:

Models 7777 and 7778 cover both VHF and UHF bands with separate amplification in each band for maximum signal handling. They may be configured for either separate or combined VHF and UHF inputs.


When configured as a separate UHF amp is the any difference between this and a UHF only amp? Also what model Winegard are you using. Thanks.


Jay
 

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Bumping to the top. I am going to order a 7775 or 7777 on Monday and am still trying to find out if there is any reason to get the 7775 over the 7777. Thanks.
 

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jerndl,


Which did you order and are you satisfied with it? I am trying to mull through wether to get the CM7775 or the AP4800 versus the CM7777.


I plan to have two antennas. A UHF only (either the CM 3021/4221 4-bowtie, the 4228 8-bowtie or the 4251 parascope) to pull in the digital channels from 60 miles afar and use a separate non-directional VHF for the local analog. The VHF may not need amplification, however I will need to combine the satellite, UHF, and VHF into TWO signals for input to the Hughes E86 receiver. (The Hughes has an OTA/CATV antenna input as well as a combination satellite/OTA input.)


It seems that the 7777 could combine the two OTA antennas and leave the satellite on a separate channel.


Anyone?


TIA,

NE
 

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Quote:
Originally posted by NakedEngineer:
jerndl,

Which did you order and are you satisfied with it? It seems that the 7777 could combine the two OTA antennas and leave the satellite on a separate channel.
I got the 7777 and it seems to work ok for me. I still can't be sure because only one digital station (in the Orlando area) is broadcasting reliably at this time. There are a few other stations that are "testing". It works great for the one station, but I can't tell for sure how it's going to work for the others.


I belive you can combine two OTA antennas (UHF and VHF) with the 7777. However it will amplify the VHF also. Good luck.


Jay
 

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I talked to the product manager at Channel Master about this and other issues.


His recommendation was to use a UHF-only preamp such as the CM 7775 if you were only interested in receiving UHF, which is often the case for DTV/HDTV.


He didn't say so directly but my assumption is that there are compromises involved in the design to allow the 7777 to amplify VHF as well as UHF.


An installer here in the Bay Area echoed these sentiments.

 

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Just make sure you know what you need for your system before you make a decision.... I thought that all the SF Bay Area digital channels were on the UHF band, so I installed a CM4248 yagi and the CM7775 UHF-only preamp. Well, it now turns out that one of our digital stations is VHF - the one that will carry NBC next year! My old pre-amp allowed the VHF signal to pass through, even off of the UHF yagi. But the CM7775 killed the VHF signal and does not allow it to pass through at all, so I've lost a channel due to going with a UHF-only preamp.
 

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Quote:
Originally posted by NakedEngineer:
It seems that the 7777 could combine the two OTA antennas and leave the satellite on a separate channel.
Yeah, has anyone tried this? The UHF performance of my UHF/VHF antenna has been less than optimal, so I was thinking of adding a UHF-only antenna . . . but the terrestrial analog/digital add-in module for the E* model 6000 only has 1 input so I have to combine the UHF & VHF signals onto one RG6 (also, it would be nice to have one RG6 for the TV's internal tuner). So, I wonder if I could have a 7777 combine a UHF-only antenna with a UHF/VHF antenna?
 

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Quote:
Originally posted by dagman:
So, I wonder if I could have a 7777 combine a UHF-only antenna with a UHF/VHF antenna?
With certain types/models of VHF/UHF antennas you can easily remove the UHF portion of the antenna and move the mounting bracket to compensate for the change in balance.


Jay
 

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Eric,


IMHO your location is way more important than the antenna/amp brand. If you are in an "easy" location the Radio Shack antennas and amps will work fine. In the more "difficult" locatations the little extra added perfomance of the better brands may be the only way to get acceptable reception. Try the $40 RS antenna mounted amp. If it doesn't work you can take it back. This is the approach I have taken. I first tried a RS antenna, then added their amp. I still was not getting acceptable receiption, so I took the RS stuff back and got a Channel Master 4228 antenna and 7777 amp. There was a slight increase in signal strength, but it was enough to make a difference. Good luck.


Jay
 

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Don't forget, gain is not the only characteristic of an amplifier. Another important one is noise figure. The CM amplifiers have a noise figure of 2 dB which is much better than the RS crap. The RS amplifiers have horrible noise figures -- amplifying the noise along with the signal making them useless in weak signal environments.


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The below web page was done to compare three antenna pre-amps. I currently have the RS, but since I am within 30 days - IT WILL GO BACK.

http://www.projectorexpert.com/pages/preamp.htm


The units that were compared are: Terk's PDMA mast-mount preamp, a combo VHF/UHF/DSS preamp and combiner; Radio Shack's model 15-1115, a UHF/DSS preamp that passes VHF and FM signals, and Channel Master's #7775 Titan 2, a UHF-only design that won't handle any other types of signals.


The "main site" has several other interesting reads:
http://www.projectorexpert.com


Check it out!


And thanks to all those that commented!

NE
 

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Quote:
Originally posted by jerndl:
jhe,

.............................................

When configured as a separate UHF amp is the any difference between this and a UHF only amp? Also what model Winegard are you using. Thanks.


Jay
If the amps are truly separate and get combined with proper filtering at the output, they could be equivalent. But I would worry about compromises made to cut costs: The main problem here is that in the old days, VHF was probably considered more important than UHF, so corners might have been cut in the design of the UHF section, unless the design is new. Only way to be sure would be to get more info from the mfg, or test each kind.


I have Winegard AP-4700 and AP-4800 preamps. I also have a UHF Titan and a couple of Radio Shack preamps (old). My AP-4800 works best for me, but I use all of them: RS in my attic, AP-4700 and Titan as boosters, and AP-4800's at my outdoor antennas.


(I have multiple antennas since I need rotors, and want to be able to record and watch in different directions.)
 

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The 7777 has seperate amplifiers for UHF and VHF. The only common components shared are the coax feed and power supply.


It is designed to take the input from two seperate antennas. And, that is indeed how I am using it. I have a huge CM crossfire VHF ant and the CM4251 UHF parascope.


Multipath is not caused, or cured by the amplifier. Reflections of the TV signal received out of phase cause the multipath problems, and are amplified along with everything else in the amp.



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Can the CM 7777 be used to combine two separate antennas?


Specifically, a CM 4228 and an older CM ??? VHF only antenna. Does the CM 7777 have filters on the respective UHF/VHF inputs to prevent "multipath" problems ("multipath" may not be the correct term here). By "multipath", I mean creating a shadow UHF signal with the VHF only antenna that interferes with the CM 4228 signal. Is signal canceling going to be a problem?
 
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