The DCI filters are VERY good but are designed, as standard, to provide a bandpass between 144-148MHz!
I guess a special version that is either much narrower, or is setup for 142-146MHz, might give maybe 20dB of attenuation ...maybe this plus your cavity as a suck out notch/rejecter after preamp would be a winning combination? good luck Graham G3VZV ----- Original Message ----- From: "John Geiger" <aa...@fidmail.com> To: "Werner Kullmann, HB9BNK" <hb9...@uska.ch>; <amsat-bb@amsat.org> Sent: Wednesday, April 27, 2011 3:04 PM Subject: [amsat-bb] Re: searching advice on low hpass filter for 146 MHz >I believe DCI makes a 144-146 bandpass filter. > > 73s John AA5JG > > ----- Original Message ----- > From: "Werner Kullmann, HB9BNK" <hb9...@uska.ch> > To: <amsat-bb@amsat.org> > Sent: Wednesday, April 27, 2011 1:41 PM > Subject: [amsat-bb] searching advice on low hpass filter for 146 MHz > > >> To improve the reception of the sats on 145.9xx MHz with my >> little yagi, I recently acquired a SSB-preamplifier SP-2000. To my >> dismay, the reception on my IC910H was intermittend heavily >> distorted. >> >> After a while I found, that a nearby located commercial >> transmitter (POCSAG) emitting bursts on 147.300 is so strong, that >> the frontend of the IC910H (or its AGC) practically quites the >> receiver on 145.900. When the bursts stop, reception resumes. >> Difficult to qso. >> >> I have experimented with a large cavity filter and found, that the >> impact of the bursts can be reduced, so that normal satellite work >> is possible again. >> >> Now I am looking for advice on how to build a steep low pass >> filter, eliminating everything above 146 MHz, to be mounted before >> the preamp on the mast. The filter must however be capable to >> accept the rf power, if I work in V/U mode. >> >> Thank you for any ideas ! >> >> Werner, HB9BNK >> _______________________________________________ >> Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. >> Not an AMSAT-NA member? Join now to support the amateur satellite >> program! >> Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb > > _______________________________________________ > Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. > Not an AMSAT-NA member? Join now to support the amateur satellite program! > Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb _______________________________________________ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
