Originally Posted by rbsfinav
Thanks for responding.
My antenna is capable of receiving UHF/VHF/FM/Digital so I don't think that is my problem. I used to receive KMG (7.1, 7.2, 7.4) with no problems up until a few months ago.
On my DTV I am receiving KUSA on 9.4. I also have an analog TV with a digital converter that receives KUSA on 9.1 through 9.4. KUSA 9.4 is at a signal strength of 88 while, as you indicated, 9.1 through 9.3 are at a lower signal strength (66). My DTV does not show signal strength.
At the suggestion of another member I disconnected my amplifier and now the analog set receives KMGH 7.1, 7.2 and 7.4 (I think) at a signal strength of 66 but they show up as KMGH 82-1, Azteca 82-2, and LAFF TV 82-3 even though they are displayed sequentially between channels 6 and 9.
After many rescans my DTV does not register any of them. Interestingly my analog set also receives many other stations that my DTV does pick up. Several of these stations have relatively low signal strengths (60s) but KBDI (PBS channel 12) has a strength in the 80s yet my DTV doesn't pick it up.
The DTV is 6 years old so maybe the tuner is just wearing out, if that's possible.
Thanks for your comments.
I don't think it is possible for a tuner to "wear out", but it could certainly be damaged by either a power surge, lightning strike, or even a static discharge. But I doubt any of those are what are causing your problems.
I also doubt that the amplifier was causing a signal overload on KMGH. That was more of an issue with older equipment, whereas your equipment, although "old" for the digital tuner age, could probably handle significant signal strength (note I am not saying the issue is definitely not due to signal overload).
If removing the amp helped, my theory is that the amp wasn't very good in the first place. There are many bad amps out there, which tend to boost the signal, but add more noise or distortion at the same time, which damages the signal rather than helping, especially for digital.
In most cases, I don't recommend a distribution amplifier be used. It's much better to use a quality antenna pre-amp installed right at the antenna, which preserves the signal at the point of reception and boosts it enough for good distribution. You can choose an appropriate version depending on how many passive splitters you need after the preamp. Again, a low quality pre-amp will hurt more than it helps. An antenna pre-amp is especially helpful if there is a long run of coax from the antenna to the TV (which is typically the case with an outdoor antenna).
Since you're reception changed, it most likely is due to something having changed at your location, or between your location and the broadcast antenna. Older digital tuners were highly susceptible to multipath distortion, i.e. the signal coming from mulitple paths, due to reflection off of other things. Even if you have a clear line of sight to Lookout Mountain, you could still be affected by this. Newer generation digital tuners are a lot better at handling multipath distortion.
So, any new tall buildings erected nearby? New houses that block your line of sight to Lookout Mountain? Trees in your line of sight (particularly close to the antenna, i.e. your yard or a neighbors yard) grow bigger over the last few years?
Another possibility is connection or even coax degeneration over time. Especially for the outdoor connections (since you say your antenna is installed outdoors). In particular moisture can get into connections if they aren't properly weather sealed.
Yet another possibility is antenna damage. If your antenna is a true UHF/VHF antenna, the VHF component may have longer elements that could be damaged in high wind. Are you sure you still have all your antenna elements?
I will also note that some unscrupulous antenna manufacturers may market an antenna designed for UHF reception as UHF/VHF if it has any sensitivity at all in the VHF range. Do you actually have some documentation regarding antenna gain in the VHF (high VHF in particular) range? What antenna do you have?
Also, can you share more about your installation, i.e. besides antenna model, things like how long the coax run is, what type of coax was used, what if any splitters are in the signal path, what kind of distribution amp were you using, etc.
On another note, if your digital converter box is using 82 as the major channel number for your KMGH subchannels, that is an indication that it is receiving both the KMGH signal and the KZCO signal, and it is choosing to put one of them in the 82 range to resolve the conflict of the duplicate channel numbers. It's not clear why there isn't another set at 7.1, etc. Some tuners don't handle duplicate channel numbers well at all.