QRSS Beacon assembled, but not quite right…

December 31, 2011 | Amateur Radio, QRSS | By: Mark VandeWettering

I ordered myself one of Hans Summers’ QRSS beacon kits before Christmas, and it arrived a few days ago. Yesterday, I started tinkering it together, and today got it hooked up and began testing.

First, the good news:

  1. The oscillator is running.
  2. I was able to adjust it with the trimmer to get it into the MEPT portion of the 30m band.
  3. The AVR is alive and running.
  4. Tone output works, and it is detecting the 6s per dit QRSS mode properly.

But… all is not well. Here’s an example output recorded with Argo on my FT-817 placed adjacent, without any antenna at all. The QRSS beacon is transmitting into a 1W 47 ohm resistor that serves as a dummy load.

As you can see, the output is a bit wavy, and looks a bit unclean as well, with lots of spurs. But the primary thing is the deviation is only about 1.5 Hz (I recorded this in 10 second dit mode on Argo). I tried adding some additional twists to the gimmick cap, but that didn’t seem to help much.

I suspect the general poor quality of the output may be because I’m using a 5v power supply of unknown quality (perhaps some additional filter caps across the power leads may be helpful?). I’ll probably try to make a longer gimmick tomorrow. I also am going to get it hooked up to the scope to adjust the power properly as well. It’s also not in a box yet, and my dining room table is a bit drafty, so thermal drift is a distinct possibility.

Anyone else have any ideas on how to tame the ragged castle walls?

Addendum: I couldn’t let it sit: it’s one o’clock in the morning and I decided to make a new gimmick and try it out. And, of course, it worked a lot better, giving about 30Hz of swing! Ouch. I trimmed the length down, and unwound it a bit more, and now it’s down to a more respectable 8 or 9 Hz. I’ll probably unwind it a bit more when I get it in the case and setup for final operation.

But here’s an odd thing: I jumpered it for 6 second dits by jumpering the 2-5 connection at the top of the AVR, but it’s acting as if is set to 15s dits. Do I need to ground pins 5 and 6 as well? Perhaps they are floating?

Addendum2: I suppose I should have read the Important note on this page.