Tks all for your answers. The channel in question is WATM Altoona. It's ch 23 analog and ch 24 digital with 3 subs including 24.1 ABC-HD. By my estimate WATM's tower is about 25 miles from me on a heading of about 236º true. I'm definitely not LOS, being on the wrong side of the ridge. But since I get something on the analog channel I hold hopes for the digital signal.
AAMike - I'll try AVS. I haven't been in that forum yet because my work network (where I do most of this SG activity during breaks) blocks that site. I'll try from home.
messarano - 16877 if that helps, but more exactly I figure I'm at about 40º 42’ N, 78º 6’ W. I'm using 10º 30' W declination in my calculations. I get most of my information from Broadcast Television Station Search at
http://www.2150.com/broadcast/default.asp using those location values. (The long. and dec. numbers have to be entered as negatives.)
NightHawk - Tks again for your answers. FWIW, I'm an EE by training and I have worked "around" RF much of my career including my present job and a 2-year stint 10 years ago designing/testing XOs. So nothing you're talking about is foreign to me. I don't work with the details every day so some important stuff has no-doubt escaped me.
There are no local stations except some presumably low-power translators at about 125º and 9 to 12 miles, on channels 13, 29, 36, and 39, IIRC. I have thought about the overload consequence and it's certainly possible, but I think unlikely because of the situation I mentioned with the adjacent analog signal. Regardless I have a variable attenuator and I have used that at various times to see if I might be overloading the tuner inputs (I know what that looks like) but to no apparent avail. The attenuator definitely has a predictable affect on the snow level of that analog channel. I would expect it to have exactly the same effect on the digital signal. This leads me to believe I still need all that gain.
I am also considering multipath, and I think this may be the real problem. I can't really see any evidence of it in that particular Ch 23 analog signal (too snowy most of the time, but clear enough at others), but my analog ch 10 - co-located with ch 23 - has always been "ghosty" on my old antenna. It is less so with the 4228 - in fact the 4228 gives the best PQ I have ever seen on that channel OTA! But there is still some echo there. Here's a strong clue: I get the best lock on ch 24 with the 4228 pointed 35º south of where I think it should be pointed, i.e., at about 200º true vs. the expected heading of 235º. I'm sure the orientation of my CM rotator is off somewhat but certainly not to that extent! So I guess I have a stronger and variable indirect signal for ch 24 ?? (That is not necessarily the case for ch 23 which has a variable and equally ugly picture over quite a range of headings in that general direction. It's best picture with least noisy sound seems to occur somewhere around 220º.)
I know I can't amplify to any avail a signal that isn't there. Last night I was again getting ch 24 "loud and clear" on my Sony TV and it was stable all evening. Even my 811 could lock it, indicating a 60+/100 signal at that 200º heading, but it had a lot of drop-outs as expected. (I didn't get to try the 622.) I'm thinking I'm seeing a pattern here with the temperature. On cold, clear nights like our M, T, and Th, I was able to lock 24. On the warmer nights like Su and W I was not. I'm guessing that temp. might very well change the signal propagation (strength) based on my short wave experiences, but would it likely change the path, i.e. signal reflections in a horizontal plane?
On the nights when I can lock it I will do all possible experimenting to see what if anything makes any difference. That's where I thought a SS meter would help. I'd like to borrow or even buy one. I might be able to borrow one from work. I could ask to borrow an HP8560 SA, but that's a long shot. What I really need for at least part of my investigation is something that will give me a continuously-variable SS indication so I can at least see where the strongest signal is coming from. How can I resolve the multipath? I know the SS meter won't help with that other than to confirm a strong(er) signal from more than one direction. Will the SA indicate a difference in the two signals that are on the same frequency, but where one is delayed/phase shifted a bit?
Now that I have everything 35' in the air and cold weather is upon us, I can't really do anything about the antenna or preamp until the spring. I realize I can't improve on the 2dB noise from the 7777, but I assumed another amp with a similar or lower figure probably wouldn't hurt much. The noise is additive, right?
I'm willing to throw more time into the experimentation while I have it during these cold months, and perhaps even some more money. The learning opportunity far overshadows the frustration, even when I really want to watch something on ABC-HD on a day I can't lock the signal.
Your continued support, as your time allows, is certainly appreciated...!
Have a great weekend. At this point I probably won't reply before Monday...
