2007-02-25
Exciter in a Box
Jaycar (Electus actually) supplied the final critical piece of the exciter, the Aluminium box. Some metal bashing later and the unit has a case.
The 12 Volt supply was brought in through a feed-through capacitor. A mica washer and bolt insulator mounted the IRF510 to the case, which proved to be a sufficient heat sink. The audio signal was brought in through a RCA socket, and the RF taken out via a BNC.
The final power amplifier stage is the next project. The receiver work also continues. A 24 Volt PSU with current limiting has to be built at some point before the transmitter can hit full power, but it might be practical to test the final stage at lower power levels using my current variable limiting supply.
If I had a suitable antenna for 80 metres (yet another project I need to do very shortly), I could probably use this unit with a lashed-up T/R to actually hold a QSO. I might give this a try before I build the power amplifier, if the opportunity presents itself. Perhaps some of the other members are also at the point where they can test their creations? It would be quite neat to use challenge transmitters to conduct a local net at some point.
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Parent article: "2007 80m Homebrew Challenge".