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).