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Old 6-Jul-2016, 6:14 PM   #16
rabbit73
Retired A/V Tech
 
Join Date: Aug 2012
Location: S.E. VA
Posts: 2,736
TV signals:
http://www.tvfool.com/?option=com_wr...e2cb66d645b7e9

Strongest TV signal is WUNI at -62.4 dBm = -13.6 dBmV

max input of 7777 = 15 dBmV

-13.6 dBmV + ant gain 13.7 dBd = 0.1 dBmV, no preamp overload from WUNI

-62.4 dBm + ant gain 13.7 dBd + preamp gain 30 dB = -18.7 dBm, no tuner overload


FM signals:
http://www.fmfool.com/modeling/tmp/7...5/Radar-FM.png

strongest FM signal WORC = -26.7 dBm

-26.7 dBm + ant gain ~6 dB = -20.7 dBm = 28.1 dBmV, preamp overload

turn on 7777 FM filter
28.1 dBmV - 15 dB = 13.1 dBmV, preamp probably OK, no guarantee

WORC freq 98.9 MHz

External FM filters getting hard to find; no more Radio Shack, or MCM, except maybe on Amazon or Ebay

Antennas Direct has a few left; when they are gone, no replacement
https://www.antennasdirect.com/store...on_filter.html



Insertion loss for TV signals probably about 1 dB.

A HLSJ can also be used as an FM filter:

__________________
If you can not measure it, you can not improve it.
Lord Kelvin, 1883
http://www.megalithia.com/elect/aeri...ttpoorman.html

Last edited by rabbit73; 6-Jul-2016 at 7:23 PM.
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