I have long since adopted the principle that if something is working, it is best left alone, and if to be left alone, it should first be built to a standard such that it should also look good.
Earlier in 2003, I made the decision that I would at some point, re-box my 23cm transverter. Now in November, and having just resurrected my 13cm kit, I felt that it was fitting to honour my ‘re-born’ 13cm transverter with a similarly attractive case.
Since transverters tend to be by nature an extension of the ‘prime mover’, in my case my old but trusty IC260, the transverter itself requires very little in the way of front panel annotation. Thus, I have gone for a minimalist approach, painting the front panels matt black with nothing more than an identifying legend and two miniature LEDs: A green one to indicate that the 13.8V line is live and a red one to indicate that the transverter is in transmit mode.
13cm on left, 23cm on right
Internal view of 23cm transverter
Internal view of 13cm transverter
The 23cm transverter is based on DB6NT’s MK1 version as published in DUBUS 4/92. The only difference being that I employed a Mini-Circuits SAM-5 mixer of which I have many, instead of the Synergy SMD-C3 specified in the DUBUS article. As can be seen in the photograph, the basic transverter is tiny, measuring only 75mm by 55mm. On it’s own, the transverter delivers around 1.2W with very respectable receive performance. The overall performance is augmented by the inclusion of a GaAsFET pre-amp utilising an Avantek ATF-10135 (bottom right) and a 20W PA utilising a Mitsubishi M57762 power module (far left).
The 13cm transverter is a real mixture of technologies and has evolved as a result of availability, rather than necessity. The basic transverter (top) is based on DB6NT’s MK1 version as published in DUBUS 3/93. The only difference being that I employed a Mini-Circuits ADE-3G mixer, instead of the Synergy SMD-C3 specified in the DUBUS article. The PA (bottom) is from my original 13cm kit dating back to 1986 and uses bipolar devices in the form of a BFQ34 driving a BFQ68 delivering about 3W. The pre-amp (left) likewise, was also part of my original 13cm kit, but has been subsequently modified to be a no-tune affair employing an MGF4919 HEMT.