Herb, I built two such filters based on construction directions found on page 500 of the 1973 ARRL Handbook under Strip Line Filters. I have seen the filters in several issues of the Handbook and they are simple enough that I expect it will be shown in other years of the Handbook. I used them in my full duplex satellite operations. The third harmonic of my two meter uplink transmitter fell near my downlink 70cm frequency and was causing desensitization in reception. The parts were an aluminum mini-box, two coax recepticals mounted on the box, an air variable capacitor (disc for UHF). The strip line is a strip of aluminum mounted end to end in the box. Let me know if you can’t find the article and I’ll copy and email it to you. The filters got rid of the descendent problem.
73, Roy Welch, W0SL
Sent from my iPad R/D/Gd/Ggd
On Jun 9, 2021, at 11:03 AM, Herb Sims herb.sims@mchsi.com wrote: I have looked all over the place for Bandpass filters for both 2m and 70cm antennas to put in front off my LNAs.
Any companies in the US that sells them?????
Thanks,
Herb
Please excuse any typo's as this was sent from my iPhone.
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