Hello fellow feeders and listeners,
Attached is an audio file which shows the effectiveness of using a filter such as the HPN-30118 to reduce interference from FM broadcasters which can cause a loss of sensitivity in most scanners.http://www.scannermaster.com/HPN_30118_Combined_Notch_Filter_p/24-531024.htm
I will leave the squelch open on my Uniden BC785D for this demonstration.
We hear Qantas 73 "heavy" checking in with San Francisco tower (120.500 MHz) for a landing clearance.
The white noise you hear immediately following is where the tower is giving the landing clearance. You can hear the Qantas acknowledging the landing clearance for 28 Right. Notice we didn't even hear the tower at all? Just noise.
I inserted a sequence of DTMF tones to mark the audio recording for "without filter" and "with filter".
It's like night and day. You can now hear the tower transmissions including aircraft on the ground with the filter in place.
Hope this audio example can be useful?