Would a FM Filter clear out freq. in the 400-500 mhz range?

5Rya · May 28, 2016

EDIT: Meant to say "help" out freq not "clear" out freq in the title, For some reason it won't let me change the title.
I am pretty sure that I have some FM transmitters that are overloading my scanner but if I get a FM Filter will it help the freq. higher up in 400-500 mhz range as most of the channels I listen to are in that range or will it only help the freq closer to the FM freqs? Thanks

RFI-EMI-GUY · May 29, 2016

The filter should do fine.

5Rya · May 29, 2016

RFI-EMI-GUY said:
The filter should do fine.

So it would help the freq in the 400-500mhz range become more clear and not contain as much interference?

RFI-EMI-GUY · May 29, 2016

If your scanner has such poor front end filtering (as many do) that a nearby FM broadcaster is overloading it, an FM notch filter should help. If you are getting fourth or fifth harmonic energy from the broadcaster, it might not.

gewecke · May 29, 2016

IF you're talking about a FM broadcast filter, then NO it will have little effect on 400 mhz or above. It may be a paging transmitter causing intermod, in which case you would need a filter from PAR to attenuate the intermod. 73, n9zas

5Rya · May 29, 2016

gewecke said:
IF you're talking about a FM broadcast filter, then NO it will have little effect on 400 mhz or above. It may be a paging transmitter causing intermod, in which case you would need a filter from PAR to attenuate the intermod. 73, n9zas

How would I find out what freq is causing the issues? The only reason I suspect fm transmitters to be a problem is that when I run close call it always spikes heavily in the 88-108 zone where there is little spiking in the other freqs.

gewecke · May 29, 2016

Hmm... then maybe it is a broadcast FM station creating desense or something, but usually it would be a paging transmitter around 454-455 mhz. Try your filter & see if it helps I guess. I have a FM broadcaster that I can see the tower of, maybe 1 mile away, from the window where one of my scanners are. No problems from it. 73, n9zas

Would a FM Filter clear out freq. in the 400-500 mhz range?

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