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Old 11-Jul-2019, 7:54 PM   #2
rabbit73
Retired A/V Tech
 
Join Date: Aug 2012
Location: S.E. VA
Posts: 2,544
Hello, mark





I don't think you need an antenna with more gain. You already have signals that are strong enough to cause overload. And you certainly shouldn't add a preamp.

The strongest signals that cause overload will create spurious signals from IMD (Intermodulation Distortion) that will raise the noise floor and wipe out any desired weaker signals

Not only are your TV signals very strong, but you have the strongest FM signals (dBm column) that I have seen in a long time that will cause overload.
http://www.fmfool.com/modeling/tmp/f...6/Radar-FM.png



One measure of signal strength is Noise Margin on a TVFool report. Even without adding the antenna gain, many of your signals are high enough to cause overload:



Interpreting Noise Margin in the TV Fool Report
http://www.aa6g.org/DTV/Reception/tvfool_nm.html

It is possible to add an FM filter or two in series and ground the coax shield, but attenuating the strongest TV signals will be more difficult.
You could try inserting an attenuator to make all signals a little weaker.

It is possible to order a custom channel 31 filter to attenuate your strongest signal KGBT, but you would have to reorder when they move to channel 18 during Phase 9.

https://rabbitears.info/repackchanne...=&lss=&status=
Attached Images
File Type: jpg markandeglaTVFreportRE.JPG (181.1 KB, 156 views)
File Type: jpg markandeglaTVFreport.JPG (182.1 KB, 154 views)
File Type: jpg markandeglaTVFreportFM.JPG (98.7 KB, 153 views)
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Last edited by rabbit73; 11-Jul-2019 at 8:47 PM.
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