OBSERVATIONS FROM SCOTLAND                            24 September 2009                                GM1SXX

RA1772 meets MA1720  Experiment #1

To be a success, my plan to use the RA1772's synth to drive the MA1720 for transceive operation depends on the local oscillators operating on the same frequency offset from the IF, so I hatched a 'cunning plan'.  Set both units to 1Mhz and measure the LO frequency. Then set the units to 30Mhz and measure again. If they agree... great, my idea has a chance of working. If not, well err...tough!

(Measured using a Hunter FC-130 counter calibrated against a RACAL 9420 5Mhz reference Oscillator)

So the errors are small and acceptable.  Better still, the receiver LO has a surplus of drive so I can fit a simple PI attenuator between the receiver output and transmit strip mixer to set the drive level. It would indeed appear that I can use the RA1772 local oscillator to drive the MA1720 mixer.

73 Al.
GM1SXX
 

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