The KD0FNR KO6BTY Auto Keyer From a PicoW

We built a keyer!

KO6BTY was gifted a FT-840 by the family of a silent key over the holidays. (It was very, very nice of them. Thank you all!)

She also received a straight key kit from W1REX. (Thanks Rex!)

Daize—as she's kown in these pages—quickly constructed her key; she and I added a 10 meter dipole to our now growing antenna farm; and the kid was up and transmitting CW on 10 meters with her technician class license! Also! She's a new SKCC member!

Here's the thing though. Neither one of us is good enough with a straight key—she's better than I am to be frank—to convince the Reverse Beacon Network that our callsign is actually decipherable. So, to make sure our signal was getting out and to help people spot us for event lke SKCC's SKM.

Project TouCans has a memory keyer in the Rockmite that works quite admirably for just this sort of thing, but now so much the venerable FT-840.

That's ok though. We built our own autokeyer! Here it is in all it's early-prototype glory.

Just in case you were wondering... Yes, yes I was trying to use that C-clamp as an inductor and most of the rest of this post will in fact be about RFI

The 12, 11, and 8 year old gang have been working at teaching themselves Python using a Pico W and a set of videos on YouTube. One of the video lessons detailed how to blink an LED with the Morse Code for whatever had been input at its prompt. Voila! That was the codebase for the keyer.

Coding was the easy part as it tunred out. We had to figure out how to change the words per minute (WPM) speed of the code, and then we were off and running.

Building the hardware wasn't too daunting either. Once again, we had a video to work from and I'd already purchased a package of very cheap relays from Amazon.

What KO6BTY and I weren't counting on—and we really should have—was RFI. We struggled quite a bit with the issue. Our relays were not setup in anyway shape or fashion for RFI and our rig—as usual—wasn't grounded (I mean, come on, it's in a 2nd floor kitchen; even if we grounded it, it wouldn't be grounded.) The first problem was that the RFI eminating from the rig's case reset the USB connection from the Chromebook to the Pico W. it was easily solved by moving the Pico W a few feet away. The next issue was that the RFI actually made the relays stick in the key down position. Talk about a positive feedback loop!

We tried adding a second relay in series with the first one to provide more isolation. It didn't work, while the first relay no longer stuck, the second one did. We tried adding 8 mH of inductance to one of the key leads. That did buy us usage of the rig up to 22 Watts. Beyond that, though we were back to RFI induced autokeyer silence. I tried cutting one of the fancy optoisolated relay boards in half so that we only had a relay in the second stage. That made things worse.

Then, this morning, we finally hit on the solution and it was a typical Project TouCans solve. When I lay both hands on the FT-840's case, I create enough of a capacitive coupling to shunt the RFI in sufficient quantities away from the keyer and we can use up to a hundred Watts of transmit power!

After that, well, yes we did turn up on the RBN

And even (although it's SKM so I didn't use the autokeyer) made a few QSOs!

Pssstttt, also, one of the QSOs to Texas and the QSO to West Virginia were QRP on 20 meters.

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