Australian Ham Radio Discussion Forum ( AHRDF )

Recently, an old home-brew project of mine which I'd long forgotten about turned up at my local radio club (Geelong ARC) among donated "junk". It is a 6m transverter that I built over a weekend from accumulated parts from my then junk-box. This was in the early 1980's, hence my previous call sign, VK3BRZ, scribbled on it. At the time I had a TS-520S transceiver to use as a tunable IF, so it was a very simple matter to construct the transverter using mostly valves as the various voltages from the TS-520S internal power supply could be used to supply it.

The transverter lineup comprises the following:

Local Oscillator: 12AT7
TX Mixer: QQE03/12 in push-push configuration
TX Power Amp: QQE03/12
RX Amplifier: MPF131
RX Mixer: MPF???

Output power was about 10W, enough to drive a QQE06/40 PA that followed (I may have photos of that, too).

I don't recall the source of the brass enclosure. It is obviously home-brew, judging by the imprecise screw holes for the covers. Old-timers might be wondering why the PA stage is operated with the QQE03/12 twin tetrodes in parallel rather than push-pull. The answer is the enclosure was not large enough to fit the larger coils and split-stator capacitors necessary for the more common push-pull configuration. The eagle-eyed will spot the neutralisation trimmer among the circuitry.

It strikes me that so much old, home-brew gear just disappears as junk, and along with it, a part of Amateur Radio's history is lost.

Chas
VK3PY

Hi Chas
for a moment there I thought part of the RX line up had a nuvistor in it

[attachment=647]
This is my 1974 "Bomb Box Special" for 6m. I had a Lafayette HF receiver.

  Front

  SSB generator, hand ground FT-243 Xtals on 3885
[attachment=648]
 10W 6m amp, 2N5589
[attachment=649]
 VFO and other modules
[attachment=650]

Those rig photos bring back similar memories with the exception that my FT-243 SSB filter was on 5285KHz (and still have those crystals - saw them recently) in my low power solid state 14MHz transceiver and my 6M circa 1975 transverter - both used similar devices and Philips beehive trimmers. { Not sure how you get 10W from a 2N5589 though, I used the 2N5590 to get near that power. }  I made up a similar concept as a 2M transverter and had both as sub-chassis above the main chassis and the SSB 'rig' below it.  There are probably still a few odd photos of it somewhere in the ZDC/ADC archives !

The homebrew transceiver and transverters are now long gone although skerricks from thir construction still remain in the shed.

Doug VK4ADC ( ex-VK4ZDC 1967-76)