Technical Articles:
Comment? email to:
This switch box was built to allow the use of 2 different radios to be used with 3 different transverters.
Click any thumbnail for an enlarged picture.
The transceiver switch (s1) selects the radio, and switches RF, key line, and ALC feedback. The two radios it was designed for are the Yaesu FT-817 and FT-897, both of which have similar circuitry with respect to ALC and transverter output levels.
The transverter switch (s2) selects which transverter the selected radio is passed to; and the RF and key lines are the connections that are switched. The pictures above were taken of an earlier model; the schematic is of the box currently in use.
In my station, 10 mw is the power level required for two of my transverters, but 300 mw is needed for the third; each has it's own receive gain adjustment, so no provision was required to handle that parameter. All have common tx/rx I.F. ports.
I built this into a plastic enclosure, and used single-sided PC board as a liner for easy soldering, good grounding and proper shielding. Coax lines are RG-174 (not much is critical at 28 Mhz, my usual IF frequency for transverters). The front panel lettering was made with a full sheet inkjet label, and cut to fit the front and rear panels. The PowerPoint file used to create it is included here as well.