I’ve been wrestling with adding an FM filter to my Elecraft K3 main receiver for a few years now. Mostly I’ve been looking for a way of receiving AM signals, not necessarily for shortwave broadcasting since that is mostly dead at this point. But for wandering around the amateur bands and trying out both AM and FM.
I’ll also admit that there’s been a hole in the bank of five filters that is just crying out to be filled. Plus, INRAD’s annual offer to discount the filters on New Year’s Day by the number of the year has always been tempting. I’ve been able to battle it off the past few years, but this year I succumbed. With the $20.15 discount in my pocket, this weekend I installed the FM filter.
You can see the bank of filters in the nearby photo. The installation actually went quite well. I pulled out the manuals for the K3 and the KRX3 subreceiver. Pulled off the top cover, removed the KRX3, pulled off the bottom cover, and removed the four filters. Installed the FM filter and reinstalled the other four filters (all 8-pole at 2.8 kHz, 1 kHz, 500 Hz, and 250 Hz). I then put the whole thing back together. Pretty simple actually.
I did the configuration using the K3 utility. Then tested it out with a nearby 10 meter FM repeater and with WWV at 10 MHz. I set up the K3 with the correct FM repeater offset and PLL tone and stored the channel in memory. Still need to wrestle with the squelch settings. I next need to find any 6 meter repeaters.
I’m not really interested in the KBPF3 for general coverage receiving. I don’t really spend any time searching for shortwave broadcasts, which have generally died over the years, with English language broadcasts to North America at the head of the death watch. I’m not all that interested in utility station monitoring either.
This should add some more fun to my ham radio adventures. It also points out just how versatile the Elecraft K3 can be.