15 Apr 2014

Some building in the shack!

For the first time since my stroke last year I decided to build and test something in the shack (other than a loading coil). For my very wobbly self, this is a major step.  I decided to have a go at the Petitico 10 parts rig from PY2OHH shown a few posts back.

Somewhere I have a 7MHz crystal, but I could not locate it, so I built a bench version, for 3.560MHz instead. I still haven't managed to optimise values yet.

On RX the sensitivity with 600 ohm headphones was, at best -70dBm, so a strong signal is needed to hear anything. It was less sensitive with a crystal earpiece. It is possible that further optimisation might yield a few dB more, but this level I expected. The RX-TX offset seems ideal. The only real operating technique, with this sort of sensitivity, is LISTEN (for a good, strong signal) and then POUNCE. I have yet to check TX output power.

 I'd like to try it on 7MHz really and may buy some 7.030MHz crystals from GQRP club sales. On 7MHz I have an antenna and can listen for my signal on the Twente SDR RX in Holland.

The actual results are almost academic. What mattered was that I actually built something with my soldering iron, didn't burn holes in the carpet and, sort of managed, despite my severe balance problems.

I am wondering if I should open the Ultimate 3 Beacon kit box and build it or wait a few more weeks. At the moment I think I should wait. My confidence levels are still low.

The 481THz NLOS test I had planned will have to wait until I feel less giddy I have decided. Everything for now will be shack based.


TiƩgui said...

Very good Roger :)

gj7rwt said...

Fantastic Roger. Small steps to start, thats the way! I have just built the U3 myself. It goes together very easily but the soldering of the ic/module sockets does require a steady hand.

By the way, I have a spare 7.030 xtal if you need it.

de Andy

Roger G3XBM said...

Andy and Tiegui thanks.