With introduction of MAP65 software capable of resolving polarity angle from two orthogonal
polarized linear antennas, I started to look for a suitable radio system to support this on
144-MHz for EME.
In 2012 I contacted Down East Microwave about making a dual-receiver transverter for me.
It comprised of two transverter circuit boards with one cut down for only the receive function.
The LO circuit on the standard board fed both mixers. A custom enclosure was made to accomodate need for
extra Rx inputs and outputs.
Original transverter was equipped with 50w transmitting module which was replaced by a 25w module after the
50w module failed. Running full power in MAP65/JT65 the PTC heated xtal LO drifts +7 Hz in the initial
one minute sequence, but settles down to 2-3 Hz in subsequent transmissions. A PLL was considered not
essential. 25w is adequate for driving my 1500w W6PQL sspa (typically 16w for 1385w output).
DEMI made only one of these transverters. About 2014 the IQ+ dual-receiver 144 direct convertion SDR
entered the market for less cost, though not having transmit capability.
Return to Home Page