Central Maryland VHF reception help
 

Hello,
Here is my report
http://www.tvfool.com/?option=com_wr...ec12b1f6f26c55

I have a Wineguard HD7698P and Channel Master CM-7778 about 30' of RG6 down lead on a rotor. I can get 2,45,54 and various other channels out of Baltimore but 11 is weak and 13 only locks on a clear day. Out of DC I can get all the UHF stations and no VHf. It just appears that high VHF is weak at my location. My question is with the antenna I have is there a preamp that would help my situation? Or is that I'm using the tuner in the Vizio TV? The line of sight to Baltimore is clear with no obstructions. Also does a Tivo Premeire have a better tuner?
Thanks

Hi Doubler, is the antenna on the roof? If so, how far above the roofline? Thx!!

Is this a new install or has it worked well in the past but now having trouble?

Your selection of equipment seems right to me. I'd be considering interference. Interference bothers VHF more than UHF. Potential sources of interference are power line noise and home electronics.

To check for power line noise tune your car radio to 530 AM and listen for loud buzzing as you drive within a block of your home.

To eliminate home electronics, turn off every circuit breaker in the hosue except for the TV set. Next unplug everything but the TV set and preamplifier. If VHF reception returns, start plugging things in and turning on breakers until you find the culprit.

Another idea:

Open up the 7778 and ensure it's set to "Combined". Also switch the FM Trap to "IN". If the switch is set to "Separate", it will attenuate VHF by 20-30 dB.

Its a new install about 5' from the roof line. Does anyone know if the Tivo Premeire has a better tuner than my Vizio tv?

Thanks for the replies I will check the trap tomm. my roof has a 10/12 pitch and I hate going up there.

I just bought a Tivo Premiere last month while they had an OTA only special sale. This may be apples and oranges but I'll share my experience with the Tivo tuners and my Sony 46EX620.
Like you, I wanted to know if there was a difference in tuner sensitivity so I connected both to the antenna allowing quick comparisons by changing input settings. When my weakest channel was on the edge of dropping out, I switched back and forth, over an over and saw no significant difference. If one was pixellating the other was also. On a very rare occasion when the signal was low but very steady, the Sony did tend to drop out a little less but it was still what I would consider to be "unwatchable". If the SNR is swinging near or below 15dB, it's going to pixelate and drop out no matter what tuner is being used.
FWIW, I'm using a mast mounted preamp which according to what I've read, affects the ATSC tuner's noise figure in a positive way. I don't know how each of these tuners might perform without the preamp.

I have another puzzling question I unhooked my pre amp and locked on channel 11 only and its been rainy and cloudy for 2 days do you think it could be over saturating with the preamp hooked up?

By unhooked the amp you mean you went up on the roof and completely removed the preamp and now have a single uninterrupted run of coax going from the antenna to the TV? Or did you just bypass the power inserter for the preamp?

GUM asked a good question earlier. Is this a new installation that hasn't quite worked right or did your OTA setup work fine but now has a problem?

I bypassed the power inserter and it is a new installation I have had a antenna on my garage for a few years and have hade good success. The reason I put 1 on my house was to get rid of the cable bill. I really only need the Baltimore stations to please my wife, I put a rotor on to see what I could get mainly different market football games. DC, Baltimore, and Pa markets play different games. Ultimately I want to take the extra money from the cable and put it in my sons college fund.

OK, what you just said about only getting ch11 (your strongest channel) makes sense knowing only the power inserter was removed and not the preamp too. Both parts of the preamp need to be in the loop or out of the loop. An unpowered preamp really knocks the signal down but the fact that you can receive ch11 under those conditions indicates your original problem is probably related to the preamp. Looks like you need to get on the roof to verify the preamp settings or possibly take it out of the loop completely.

Update
 

Heres an update I completly bypassed the amp and it locked with good signal on 2,11,13,24,45,54-7,9 I lost 4,5,20,50,43,66 I got the channels that are most important but I wonder if there is a lower powered preamp that would help me with the channels I lost?

Those signal levels shouldn't be overloading the preamp. It is either defective, or there is a bad connection somewhere. Is the system grounded properly? If not, it may have caused the preamp to fail prematurely. I would test the preamp injector/power supply right before the TV & see if it worsens reception to determine if it is in fact defective.

If you do need to purchase a new preamp, my suggestion would be the Winegard 8700, but I would re-check all the connections one more time as well before spending any money.