[AMRadio] 1500 KHz trap for NC-156


Jim Tonne tonne at comcast.net
Sat Aug 9 13:14:39 EDT 2008


Gents:

I just called on my favorite filter design program Elsie
and came to the conclusion that going clear down to
about 3 uH (resonated with 3000 pF) would be
advisable in a 50 ohm system.  The two items would
be connected in parallel to form a trap, and that trap
would be placed in series with the receiver antenna
input.

To do that would require a variable inductor and a
fixed capacitor, preferably mica.

With inductor Q value of 200 and capacitor Q of
1500  the loss at 1800 kHz would be about 9
dB and the depth of the notch would be about 40 
dB.

These comments are in rather exact agreement with
others so far.

- Jim Tonne   Tonne Software   WB6BLD


 


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