Got the audio amp done!

Well, I finally collected all the extra bits I needed, and had an hour or two to proceed further with my Beach40 build, and got my recieve audio amplifier circuit built:

Well, after a week or so of experimentation, I’ve got a VOX circuit that works with my OzQRP MST2! In addition to the below VOX circuit, I put in isolation transformers and 40dB attenuators for the MST2’s speaker out to my sound card’s microphone input, and similarly for the revrse: sound card speaker out to MST2 microphone in.

dpkg -add-architecture i386

sudo apt-get install  gcc g++ gfortran make libfftw3-dev \
libpulse-dev libhamlib-dev qtbase5-dev  pulseaudio subversion \
libgfortran3:i386 libc6-i386 libqt5multimedia5-plugins \
qtmultimedia5-dev

svn co svn://svn.berlios.de/wsjt/branches/wsjtx

cd wsjtx

mkdir build

cd wsjtx

cmake ../

make -j4

cp ../*.dat ../*.txt ./

cp -R ../Palettes ../samples ./

chmod +x contrib/kvasd

ln -s lib/jt9 ./

./wsjtx

My legs are now a bit stiff and sore from going up and down a ladder for a few hours yesterday afternoon. Made a homebrew dipole with some cut and drilled $2 shop polyethylene chopping board and some cheap coax and wire from Jaycar. I used coax wound around a little toroid as a common mode choke

Stuffed a few more bits on the beach40. Got the ring mixer in, and the first transformer. Also managed to solder a SOIC-8 chip to a MePad :)

Today I’m at home watching the kids, and I decided to try some 20m contacts. After mucking about a bit with end fed half wave antennas, and not being happy with it, I decided to make the wire as per the instructions for the L-Match tuner I built (based on Peter, VK3YE’s HF Portable youtube series), and 22m of wire appears to work much better than the 12m I did have.

I made a contact with Ron, VK3AFW portable 4, as he was doing a SOTA activation on VK4/SE105, which is a distance of 1249.8 km from home and I got a report of 5 and 7, which I hope isn’t too bad with my 5 watts output.

Yay :)

Well, after some help from the Minimalist-QRP yahoo group and members of the #technest irc channel, I’ve got my oscillator going a bit better!

It now covers from 7.0041 MHz to 7.2405 MHz, a much more useful range of the 40m band!

In the end I used two 7.2 MHz ceramic resonators in parallel, with the O leg of a jaycar varicap and a 1 µH inductor in series with that.
(read more...)

I’ve started building Peter Parker VK3YE’s 40m Dual Side Band transciever, completing the oscillator Manhattan Style:

I’ve built it with some 7.2MHz resonators from MiniKits, and with the 60-160 pF variable cap I have, it gets me from 6.938MHz to 7.049MHz. Which is not terribly useful for the 20m band (7.0 -> 7.3 MHz). So I’ll have to tweak things and work out how to get more swing from the oscillator. (read more...)

Well, after getting my MST2 in an enclosure and looking Ok:

I went to a friendly ham’s workshop and started aligning it. The receive slug tuning and mixer balancing went perfectly well. When we got to doing the transmit tuning, things started to go a bit skee-whiff! The MST2 turned off. So we replaced the fuse, which promptly blew, and another!