OK, *= read degrees
Here's the situation. 4 transmitters> Strong VHF @ 270*, weak VHF @ 100*, 2 fairly weak UHF's at 185*. Put up a UHF aimed at the 2 @ 185* and a VHF only aimed towards the weak VHF @ 100*. Antennacraft Y10-7-13 on VHF
Antennacraft CY1470 UHF, Adjusted aim so that it would get the strong VHF off of the backside of the VHF antenna. Was all fine, I thought. Had 100 sig and qual on all but the strong VHF where it was sig 75 qual 100. Early spring I get a call saying that the channel at 270* was freezing, etc. Finally made it there today and they said it was working without freezing since the leaves came out. Took a look at the sig and qual - wow - all as before except the strong VHF @ 270*, sig = ~25 qual of 90. Got out the tools to take a look at the antenna. Opened the overhead door, located on the south of the shop, WOW, sig follows the door, as the door goes up, so does the sig lvl on that channel, right back up to 70. Right where it was upon initial install. Yeah the overhead door was open then. Yes, the antennas are on the shop, approx 10 feet above the door about 5 feet back from the south end of roof. Peak runs N-S, wood const, with normal shingles, and the overhead door is of mainly wood- composite.
I have seen buildings cause headaches before but that was metal const usually between ant and transmitter causing multipath (ghosts) on analog, many times.
But this one has me stumped.
Anybody got a clue as to what's going on here?
BTW- With the overhead door closed, I folded the reflector on the VHF up to its shipping position to degrade the front to back performance. Also readjusted aim to bring the strong VHF (@ 270*) sig to around 75, which also dropped the weaker VHF ( at 100*) sig to around 75 also. Opening the overhead, sig from 270* goes to 85. Not down to 20, so I don't think there will be issues, but has anyone had a similar experience?
Here's the situation. 4 transmitters> Strong VHF @ 270*, weak VHF @ 100*, 2 fairly weak UHF's at 185*. Put up a UHF aimed at the 2 @ 185* and a VHF only aimed towards the weak VHF @ 100*. Antennacraft Y10-7-13 on VHF
Antennacraft CY1470 UHF, Adjusted aim so that it would get the strong VHF off of the backside of the VHF antenna. Was all fine, I thought. Had 100 sig and qual on all but the strong VHF where it was sig 75 qual 100. Early spring I get a call saying that the channel at 270* was freezing, etc. Finally made it there today and they said it was working without freezing since the leaves came out. Took a look at the sig and qual - wow - all as before except the strong VHF @ 270*, sig = ~25 qual of 90. Got out the tools to take a look at the antenna. Opened the overhead door, located on the south of the shop, WOW, sig follows the door, as the door goes up, so does the sig lvl on that channel, right back up to 70. Right where it was upon initial install. Yeah the overhead door was open then. Yes, the antennas are on the shop, approx 10 feet above the door about 5 feet back from the south end of roof. Peak runs N-S, wood const, with normal shingles, and the overhead door is of mainly wood- composite.
I have seen buildings cause headaches before but that was metal const usually between ant and transmitter causing multipath (ghosts) on analog, many times.
But this one has me stumped.
Anybody got a clue as to what's going on here?
BTW- With the overhead door closed, I folded the reflector on the VHF up to its shipping position to degrade the front to back performance. Also readjusted aim to bring the strong VHF (@ 270*) sig to around 75, which also dropped the weaker VHF ( at 100*) sig to around 75 also. Opening the overhead, sig from 270* goes to 85. Not down to 20, so I don't think there will be issues, but has anyone had a similar experience?
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