I wrestled with the decision about adding the KRX3 subreceiver to my Elecraft K3 transceiver for quite some time. Then, for some reason that eludes me, I elected to spring for the investment. I guess I felt that struggling to break through pileups could be assisted by not only seeing the pile up on the P3 Panadapter but hearing the responding station on the KRX3. And that this could actually make the difference in getting into the DX station’s logbook. Time will tell on that one. I also felt that running SO2V could be a seriously helpful addition to my contest station. The reason I feel this way is that calling CQ for minutes on end, without an answer, drives me crazy. At least with SO2V I could be twiddling a dial while waiting for the run of stations to begin in response to my CQ! Time will also tell on this one, as I develop this skill set.

Regarding the kit itself, I had envisioned just plugging in the KRX3. When the package arrived, I looked over the contents and the installation manual. I discovered it was a bit more complex than that. I needed to install 7 pc boards during the installation and take apart the K3 right down to pulling off the front panel and removing the DSP board. I decided to devote my Sunday to the effort. I always like to get things done that I start on the same day and I never, ever, want to rush this type of installation. Glad that I devoted that amount of time. I took it slow and easy, took several breaks, including one to pick up some DeoxIT spray and another to watch the German Formula 1 Grand Prix. I managed to get things completed over the course of about eight clock hours. You can see some photos of the effort nearby.

I chose subreceiver filters matched to the mode that I operate, CW. I decided to go with 5-pole filters with the standard 2.7 kHz filter along with the 500 Hz and 200 Hz filters. This doesn’t really match the filters in the main receiver, which are all 8-pole filters at 2.8 kHz, 1000 Hz, 500 Hz, and 250 Hz. Even so, I felt that this would be a good match, first for the mode of operation and second, for the way that I plan to use the subreceiver. At this point, I don’t see a great deal of diversity reception going on. After all, with 100 watts I still can’t work all the stations that I can hear on this fantastic receiver. So no need to get into diversity antennas, etc.

After the installation, it was a simple matter to configure everything in the K3’s software and to update the second receiver DSP firmware. Now to update my human neural wetware in order to take full advantage of this fabulous technology in the next contest!

 

KRX3 subreceiver with complete shield installed in my K3
KRX3 subreceiver with complete shield installed in my K3
KRX3 subreceiver board with two more pc boards installed.
KRX3 subreceiver board with two more pc boards installed.
Barebones KRX3 subreceiver board with 3 five-pole filters
Barebones KRX3 subreceiver board with 3 five-pole filters
KRX3 parts kit with 7 pc boards
KRX3 parts kit with 7 pc boards
K3 front panel and the main DSP board with 2nd DSP board installed
K3 front panel and the main DSP board with 2nd DSP board installed
Close up of the 2nd DSP board on top of the Main DSP board
Close up of the 2nd DSP board on top of the Main DSP board
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Jim-K5ND

Freelance writer and active Scouting volunteer. Retired publishing and communication executive who writes for fun and to finance his hobby, amateur radio.

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