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Old 5-Jun-2017, 12:16 AM   #19
Retired A/V Tech
Join Date: Aug 2012
Location: S.E. VA
Posts: 2,286
I have the newer CM-7777 amp (one input). It is mounted on the 7 foot shaft at the peak of my roof that the antenna is attached to, about 16" of cable between them. I have about 30 feet of cable from the amp to a splitter. The new TV is about 10 feet off the splitter.
That sounds OK. I hope there is a power inserter before the splitter.

Does the reception improve if you bypass the splitter and connect the power inserter to just one TV as a test?
From what it looks like, nothing is going to get me that channel or channel 31 (-11.3NM).
Your two weakest channels are at a different azimuth, 56 degrees magnetic. Have you checked the aim?
Very wierd since everyone around me can pick it up and my system is newer and a tad higher.
It might be higher on your house, but not higher in elevation. If your neighbor to the SSW had an antenna at 40 feet, it would be 124 feet higher than your antenna.

There could be a weak link in your system. What equipment are they using?

When PCT International bought out Channel Master, they fired its best engineers and closed the NC plant. Since then, the quality of their equipment is not as good. The 7777 that I bought recently only had a gain of 23 dB instead of 30 dB as stated in the specs. They were getting a lot of returns of the 7777 because users were having overload problems with it. I suspect they made a secret redesign to try and solve the overload problem by reducing the gain.
Would it be worth it to play with a second antenna at ~10ft and see what I could get?
If you want to experiment with a UHF antenna, try a Solid Signal HDB91X, which has a tilt adjustment. Add a low noise preamp like the Kitztech KT-200 coax powered outdoor version, and new RG6 coax.

The KT-200 has a low noise figure, which allows reception of weaker signals, but is a little more subject to static damage, as is true with all ultra low-noise preamps; that's the trade off.
What about adding a 'tuned' element to the antenna?
Your CM antenna is very rugged, but I'm not impressed with the gain specs. I doubt that you will be able to improve its performance by adding an element, but you are welcome to try.

Please note that WQPX has co-channel interference from WTAJ on the same channel, but it is in a different direction.
If you can not measure it, you can not improve it.
Lord Kelvin, 1883

Last edited by rabbit73; 5-Jun-2017 at 12:44 AM.
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