I stopped working on this a couple years ago when I couldnt get the antenna matching unit to work, and decided that I would re-engineer it for a small SLAB battery, well, I never got around to that, and the original 10x AA's is probably as good as anything. The board incorporates a simple resistive current limit charger.
The ATX80 is a design by ON7YD of a 80m ARDF low power beacon transmitter, intended to be used with a simple wire antenna and concealed as part of a direction finding contest. My intention, was to use it to demonstrate ARDF to the local schools, with a view to setting up proper events.
The beacon itself worked fine with a simple wire antenna and counterpoise, the inclusion of the ATU was to allow it to use shorter wires. I suspect the design of ATU I used just isnt very good, so will redo it for another proven design.
The first challenge though is to redo the PCB standoffs to allow the board to be secure and yet allow the battery box to fit underneath it. Part of the side wall of the box will need to be cut away to allow the box to slide out when necessary.
The ATU requires not much more than a bit of a rewind, and a few more diodes. It shouldnt take long to get working and finished.
Details of this design can be found here http://www.open-circuit.co.uk/atx80.php
If your interested in Amateur Radio Direction Finding, and radio-orienteering, G3ZOI has lots of useful info, including details of events, here http://open-circuit.co.uk/wp/sample-page/about-ardf/
A few years ago myself and Sam took part in an open event near Blackpool, we didnt win, in fact we came all but last, but it was great fun! Were now fitter and more knowledgeable, so perhaps, next time...
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