Originally Posted by kevm14
Speaking of which, where did they go?
Many of us are still here, but if we don't have anything useful to say, we are quiet. Also, we don't want to give any bad advice. If we do, the Moderator or other regulars will shoot us down!
Ah, permissions issue on my Gallery. Should be fixed now. You guys must have thought I was crazy. Well anyway, check out my gain and beamwidth plots.
Nice job on the plots. I enjoyed looking at your Gallery by going to the root URL.
I think I've decided on the 7697P, 11 foot, but I'm kinda hoping someone looks at my TV fool survey and can judge my potential reception from the towers at 28 to 41°, based on the antenna gain plots.
You showed us your tvfool results and told us what channels you were interested in, you told us about your reception equipment, we talked about the possible options for you, and the appropiate antenna types. The engineer
in you has done a good job of analyzing the possibilities, now it is time for you to select an antenna and let the technician
in you test it out. When you are up there it might be interesting to temporarily swing your new antenna toward 69.1 (if you decide on a 2nd antenna just for 69.1, it will be a lot smaller being just for UHF).
The reason why you must be the final person to make the decision is because there are still some unique unknown factors at your location that would be difficult to analyze. The main one has to do with the fact that with digital, signal quality is just as important as signal strength while with analog, signal strength was all-important.
The digital tuner has an error correction system (FEC) that will correct a limited number of errors in the digital stream. Once that limit is reached, you will start to see tiles, picture freeze, and dropout when you are at the "digital cliff." Signal quality is measured by BER (bit error rate/ratio). The factors that increase BER and reduce signal quality are:
1. Improper signal level: A weak signal will cause a poor signal-to-noise ratio; a signal that is too strong can overload a tuner or preamp. A nearby FM transmitter can also cause overload, which would require an FM trap.
2. Reflections from multipath problems, static or dynamic.
3. Impulse noise in the reception area (worse on VHF).
It IS possible to have a strong but poor quality signal.
Now you know why (in post 10278) I asked about your tuner/software being able to give BER, in addition to strength. It would be useful if it also gave SNR, which should be at least 15.5 to 16 dB to obtain lock on a digital signal. I use the signal quality bar on my Apex DT502 CECB to tell me about signal quality which helps me to optimize antenna aim after first going for max signal strength.
What adds confusion to good reception is that some tuners are more tolerant of a poor quality signal than others as AntAltMike can attest:http://www.avsforum.com/avs-vb/showp...8&postcount=16
Because my tuner is also my BER meter, the correlation is good.
Since I don't know your EE area of knowledge, I might be preaching to the choir. If so, sorry.