Reception puzzle in MD

[jimadams]

Hi Richard,

Well, I'm in MD but close enough. Yes, I have the "biggest, baddest Yagi" made by Winegard that you recommended years ago and their best UHF preamp and basically don't watch cable anymore - until the Super Bowl when I lost FOX 43 (virtual 47) in the 4th quarter as reported in another thread. FOX was not the problem so here is a little mystery for you or other gurus. I spoke to the station manager at FOX York, PA and he saw no recorded power loss to their DTV antenna that night anywhere around the time period I suggested - about 9:15PM. Jim Miller claims they have an ERP of 933kW (close to FCC limit), a tower height of about 800 feet and something called "radiation height(?)" of well over that - like 1200 feet. They are about 45+ miles from me at magnetic 300 degrees, as in northwest. I can't get them there at all. I need to point the Yagi northeast to receive them where the Yagi is pretty much broadside to their tower and that's where it was for the S-Bowl.

So what's wrong with this picture? They are quite strong at nearly 1mW and he claims there is a strong lobe in my direction. We discussed this and a couple of theories came up. Since I can not get them dead-on there must be something seriously in the way (don't think so), my elevation of 170 feet and horizontal antenna orientation is basically shooting into their "dirt", or something in my RF chain is being swamped and I must off-position my antenna to 30, 40, 50 degrees northeast in order to look at a weaker reflection or use the much-reduced side-gain of the Yagi. Remember, the Yagi has an inherent gain of about 14dB at UHF 47 and the preamp I think runs at about 25dB.

Thoughts?

Jim

[Richard]

Jim,

Gonna have to leave that one with Ken.

[donshan]

Yes, I have the "biggest, baddest Yagi" made by Winegard that you recommended years ago and their best UHF preamp and basically don't watch cable anymore - until the Super Bowl when I lost FOX 43 (virtual 47) in the 4th quarter as reported in another thread. FOX was not the problem
Thoughts?

Jim

A "sudden loss" of signal that was not the station, suggests to me a failure at the preamp, RG6 cable, or the balun connection. Ken is the expert here, but here are my thoughts based on problems with my antenna .

The RG6 cable in my CM 7777 goes from an inside power box up to the preamp on the antenna. The preamp connects to the antenna with a balun which connects to two wing nuts on the antenna. This wing nut connection on the antenna was tricky to secure the wires from coming loose. Wind vibrates them. I used a plastic tie strap to secure the balun so it did not hang from the connections.

1. Was it only this channel lost? What happened to other channels?

2. Is the power still going to the inside box and are all the connections on the cable tight( including the link to the receiver)? Any possibility of water in the connections? Are BOTH wires from the antenna balun connected to the antenna? One wire loose on the balun might still provide a signal on high power stations, but you would lose weak ones. In digital if you have "just enough" signal it is perfect, and below this level you fall off the cliff. Losing one balun antenna wire could do this.
3. Is there power going to the inside preamp box? I accidently pulled the power plug on the inside power box once, while I was connecting a DVD player and lost it all on the antenna. The mystery to me was why should connecting a DVD player lose the TV channels? It was just power.

4. "Years ago"---Preamp died? Maybe run a test bypassing the preamp or replace it.

Over to Ken after these thoughts.

[jimadams]

Thanks Don. That rig of mine has been up there since late 2002 so could use a close inspection. But that Sunday was clear, dry and windless so as to not tease or make worse a flaky connection.

1) Only channel lost? Don

[kq6qv]

Jim- Your problems on Super Sunday sound like a loose connection to me. Sometimes vibration can make a slowly oxidizing connection better, so problems become more likely to show up on calm days. I suggest you disconnect and reconnect all your antenna connectors.

Your peculiar aiming problem is probably a multi-path problem, and aiming to one side eliminates all but one good path. It sounds like you are lucky: You get York by aiming at Philadelphia, so you don

[jimadams]

Sorry it's been a while but here are more hints.

There appear to be two general antenna positions where I can receive that nearly 1 megawatt FOX 43.1 in York, PA at what should be a 300 degree, northwest pointing.

1) Broadside, pointing 30-50 degrees northeast - last night it was 75 degrees.

2) Broadside, the other way pointing around 200-ish degrees southwest.

I put a switchable attenuator in front of my Sammy T-165 but still could not receive them dead-on.

Winegard suggested several solutions/reasons and one was to try the lower gain model preamp in their AP series. I can also put this attenuator in front of the hi-gain preamp I have to prove or disprove the overload theory. That, and a leak in my roof are on the "better weather" list of things to do.

Jim

[kq6qv]

It might help us some if we knew your ZIP code. -Ken

[jimadams]

Zip is 21921. On a map, I'm in the very, very most northeastern corner of Maryland.

[kq6qv]

Jim- There is a 3kw FM station very close to you (89.9MHz). But it would have to be within about 300 yards to cause you overload. There are no other transmitters close enough to you to cause overload. Antennaweb.org predicts you will not get the York Fox DTV station. I am going to stick with my 3 recommendations above. If you want better reception from channel 47 (43.1) you will have to move the antenna to a different spot. See http://www.hdtvprimer.com/ANTENNAS/siting.html . -Ken

[jimadams]

Thanks Ken. I don't believe I ever received a notice of your response back in April so was just surfing the forum today and found it. Wish I had new hints but don