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Old 15-Dec-2016, 6:50 AM   #7
Junior Member
Join Date: Dec 2016
Posts: 14
Thought about this some more and did the noise margin calculations for the worst-case 10dB stations. A big assumption in these calculations is 7dB noise figure for the Silicondust HDHR3 tuner, I can't find any specs for it.

Using a dB4e without pre-amp and 20' of RG6 I'll get maybe a 1-2 dB improvement over the in-air noise margin. I've got 12 Mt. Sutro stations between 10 and 16 dB noise margin. A pre-amp will improve this by 5dB, a dB8e antenna will improve it by 6dB (with the potential cost of degrading the Fremont stations due to narrow beam).

I think the logical progression to try is:

1) dB4e aimed at 316 degrees, no pre-amp. Not much noise margin on paper, but it is simple and may work. Check and make sure I can get KGO-TV 35 at 357 degrees, one of the weakest Fremont stations at 22dB NM.

2) dB4e aimed at 316 degrees, 3dB noise figure Juice pre-amp (may need an attenuator at the tuner input). Should get me another 5 dB noise margin and allow me to rotate from 316 degrees nearer to 357 degrees Fremont if necessary.

3) dB8e, experiments with side-lobe pickup at 357 degrees, or dual antennas with separate tuners (relatively practical with $90 network attached tuners, no RF combining).
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