ON5MF is still fond of SDR (of course)

It’s a long time I haven’t written anything about the SunSDR but apparently some people even read what I write here 🙂

So what did I do in the last 15 months?

First of all I got frustrated with the limited power (15W) so I added a HLA305v PA to my system. The HLA305v is a fairly low-cost solid state amplifier rated at approximately 300W. According to the tests of the ARRL it should be reasonably clean when using it in low power mode (+/- 200W out on the low bands, +/-100W out on 10m).

But when installing the HLA305v I had a problem, all wiring was correct and the amp went into transmit when pressing the PTT on the SunSDR but 90% of the time the automatic bandfilter switching in the amp did not work. After some research I tested with a small relay between the transceiver and the amp and this solved the problem.

When this worked as a prototype I made a little breakout box for all ports of the SunSDR:

The relay for the ptt is inside the 3-d printed box, and I have all output pins easily available now.