[amsat-bb] 70cm high-pass filter designs

Glen Zook gzook at yahoo.com
Wed Apr 15 22:27:38 UTC 2015

A 2-meter low pass filter might help even more since the 3rd harmonic of that signal falls into the 70 cm band. Glen, K9STH AMSAT 239/LM463

Website: http://k9sth.net
      From: Daniel Estévez <daniel at destevez.net>
 To: 'Amsat BB' <AMSAT-BB at amsat.org> 
 Sent: Wednesday, April 15, 2015 5:07 PM
 Subject: [amsat-bb] 70cm high-pass filter designs
Hi all,

My portable satellite station consists of a Funcube Dongle Pro+ for RX
and a FT-817ND for TX. I use a diplexer in front of the dongle to avoid
desensing, but still some of the 2m signal is getting in and causing
desensing when working V/U birds. It seems to me that a 70cm high-pass
filter in the receive chain would help.

Can anyone point me to some easy to build reference designs for this
kind of filters? Power handling is not an issue, since this will only be
used for RX. I'm mainly looking to something that I could build from
things in my junk box, using air core inductors and ceramic caps (if
this a sensible thing to do).


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