DEMI 144/28-DRX

  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.  





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