56KB Station Equipment

Transverter mini FAQ

From time to time I get asked the question "What radio do I need for use with your modem?". The answer is NONE. The reason is simple. The 56K modem is a real modem, that is, "mo" = modulator and "dem" = demodulator. Competing products at lower speeds aren't real modems at all. They are base band signal processors that rely on an external radio to do the modulating and demodulating. Voice radios are not optimized for high speed data and usually don't work well or at all at speeds above 9600 baud.

Unfortunately the 56K modem cannot be directly connected to an antenna because only the IF portion of the RF chain is implemented. The modem operates in the 28 to 30 mhz range at a power of 1 milliwatt. To be useful a transverter is required. Transverters convert the 29 mhz modem transmit signal to the UHF band of choice and boost the power to 7 or more watts. Also they downconvert the UHF received signals to the 29 mhz range. You can select a transverter for any ham band where 56K is legal. Transverters for 900 mhz and higher often have a 144 mhz IF and require an optional converter for use with the modems 28-30 mhz IF.