Had some fun playing radio at the space yesterday, but there might be another antenna/tuner issue


I was able to come in and get radioactive yesterday. I got there ~2:30 and started spinning the dial on the Alinco, tuned up on 20, 40, 80 just fine, until about 7ish. For some reason the tuner stopped reporting a match and the MFJ was reporting 3:1 SWR! I prolly should have put of a sign on the AR SIG bench but I forgot to. If someone is around the space maybe put a note up to check the SWR before trying to TX. Can we get the antenna analyzer from storage and keep it in the bin with the Alinco? It would be helpful in trouble shooting issues like this.

Ben and I also took a closer look at Walter’s blue receiver board. After double checking how he was feeding power to the Raduino we were fairly confident it wanted 12v. Powered up fine and started pulling in signals right way. It does need a broadcast band filter. Which isn’t surprising to me as my uBITX had the same issue on that antenna. The Raduino code is a rather early version of the software; again, not too surprising as the community has forked and updated the code heavily over the last year or two. That’s only really an issue because it’s trying to show/tune the frequency to too many decimal places so the last few digits aren’t stable. Which really wouldn’t be an issue except every time the frequency changes the Raduino clicks. The clicking is a known bug with a fairly simple fix. The first part is adding a couple of filter caps on the power regulator and then removing the extra unused wires.Which brings me to a question we can discuss at the AR SIG meeting on 12/16. Should we leave the demo radio as is or make the upgrades to improve it?


Did you try power cycling it? If that’s not it, hmm… Guess it’s time for more roof work.

(I have this same auto-coupler bolted to my fence with a long wire. Before that, it was on the chimney with a delta loop. No problems in the 10+ years I’ve owned it, so I’m a little puzzled by the fragility of the one at DMS.)


Yup a few times too, I was tempted to go up the ladder far enough to see if the antenna fell over or something but it was too dark by the time I actually left.


Wasn’t this antenna tuner sent in for repair last year? If so, what was repaired and by whom?


not a whole lot of details here, @krgrantham might remember the specifics of what was fixed, but it looks like it was sent to the manufacturer (SGC?)


I sent it in. It lost one of the sensors and would not tune. It was returned working but one of the buttons had two of its solder legs unsoldered and the button bent up.

It did work, was installed on the roof and did well until the antenna fell. Last I checked it still would tune even though the antenna was down - on some bands anyway.



Thanks Kevin. It had been working great since we had the antenna fixing party a few weeks ago. if no one’s free before then maybe someone could come in and meet me at the space a couple hours before the meeting on the 16th and we can take a look at it. I’d go up and check on it myself, but others comments about the structural integrity of the roof makes my ~quarter ton butt hesitant to risk it.


I could meet you at the space on Saturday but I’m not able to climb to the roof.

What are the current symptoms?



When was in last Sunday it was I made a number of contacts on 20, 40, 80 between about 2-7pm during that time the led came on within seconds of the band switches, and the MFJ meter was showing pretty much 1-1.5 to 1 within seconds. About 7pm I noticed the green led had gone out and the MFJ showed a complete missmatch. I tried power cycling the system a few times, but I never got a match again for the rest of the night.

I should be able to make it in this Saturday around 7pm.


Visited my storage unit and got the following:

  1. MFJ-29C hf/vhf/uhf swr analyzer
  2. MFJ-971 portable tuner
  3. MFJ-903 6m tuner

Also QRP Labs cw transceiver kit - can’t find details, may be missing lcd brd
SPRAT mags.
Can bring to DMS just about any time.

Also ran across some Yaesu accessories.


I’ll see if I can wander over there about the same time.



Kevin Grantham N5KRG

(214) 763-1279