FM Trap For Airband

[737mech]

Check PM's

 

[SCPD]

How's this for digging up and old grave WOW 2012 thread

You can run two of the radio shack traps in series (one after the other) and really tame the FM bands.

 

[KevinC]

How's this for digging up and old grave WOW 2012 thread

You can run two of the radio shack traps in series (one after the other) and really tame the FM bands.

Along those lines...

This filter from MCM Electronics...

FM Trap | FM-88 (FM88) | Distributed By MCM

...is only 67 cents. I bought several just because.

The insertion loss is around .5 dB. The attenuation starts to invade the aircraft band around 123 MHz at 2.5 dB and increases greatly the lower you go. The notch across the FM broadcast band is a minimum of 27 dB (on the 5 units I got) with a maximum of about 40 dB at 92 MHz or so. The attenuation on the lower side starts around 76 MHz.

I stacked 2 of these and the notch leveled out across the whole FM band around at around 45 dB, but the insertion loss was a little more than double (due to the phasing cable) and the invasion into the aircraft band was greatly increased (not frequency wise, just attenuation wise).

If you can accept the aircraft band attenuation these are a decent alternative...but I still like my PAR filter the best.

 

[verbatimx]

xeno194

can you show me in a picture RS fm trap filter inside? i would like know how is electrically.

Thank you

 

[KZ9G]

LNA for all: DIY "FM TRAP" or 88-108 MHz Band STOP filter