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Old 16-Jan-2014, 11:24 PM   #16
ADTech
Antennas Direct Tech Supp
 
Join Date: Jan 2010
Posts: 2,930
Yep, we all have....

Well, that TVFool plot explains why KFTS is so poorly received. There is a 5600' ridge line dead in your signal path about 12 miles away. That, combined with the measly 9600 watts of transmitter power from the station, means that very little signal power will diffract over that ridge and will be available at your general location.

This is a case where patience and the right mix of equipment are your two best tools. You will need a very high gain, very high gain UHF antenna plus a very low noise pre-amplifier to improve your odds. You can keep your existing combo antenna for its VHF capabilities. You will also need to select a prime antenna mounting location that is absolutely clear of physical obstructions, usually trees. Be prepared to 1) try various heights and locations for the UHF antenna and 2) adapt the antenna location with the seasons as the diffraction of the signals over the ridge line will be affected by the weather and ground conditions up there. You may find that the signals are different in the summer when there are thermal updrafts vs wintertime when the ridge is covered by snow.

I don't see any mention that you have a pre-amplifier, but one should be mandatory in this location. If you must run a very long coax from the UHF antenna back to the rest of the system, I'd recommend a high gain (25-30 dB), low noise (< 2 dB) preamp just for the UHF antenna. Your VHF could use a good boost, too, but that can probably be addressed separately.

You might want to see post 11 in this thread to gain more insight into receiving "diffracted" signals. http://forum.tvfool.com/showthread.php?t=14081

Anyway, the 91XG or the DB8e would be suggested for the UHF antenna. The pre-amp selection is up in the air as we don't yet know if the UHF and VHF antennas will be on the same mast or if they must be separated, perhaps by a wide distance.
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