[BC] Harris SX-1 Spur Problem

[Mark Garrett]

   [1]http://www.oldradio.com/archives/hardware/SXtips.htm

   Is  a good place to start if you are not familiar with the above link.
   Does  the transmitter still have the spurs when it is on a dummy load?
   How about when power output is varied, do the spurs track at -45 db as
   it is varied?  Do the spurs go away when modulation is removed?
   Mark Garrett, KA9SZX
   ka9szx at hotmail.com
       ______________________________________________________________

     From:  "James Boyd" <bbts at easystreet.com>
     Reply-To:  Broadcast Radio Mailing List <broadcast at radiolists.net>
     To:  <broadcast at radiolists.net>
     Subject:  [BC] Harris SX-1 Spur Problem
     Date:  Sun, 27 Nov 2005 07:48:35 -0800
     >I   have   a   Harris   SX-1   in   my   care   that  has  a  spur
     problem.  Modulated spurs at
     >plus  and  minus  50 kHz from the carrier at about 45 dB down from
     carrier.
     >The  usual  suspects have been checked.  PDM frequency is on at 60
     kHz.  PDM
     >waveform  is  fine.  Output  of  oscillator is spectrally ok.  All
     mosfets in
     >PDM  and  PA are ok.  All power supply voltages are in spec.  Have
     looked at
     >power   supplies   with   scope  to  see  if  any  regulators  are
     oscillating.  Nothing
     >found.  All  of  the big caps have been replaced.  Anyone have any
     ideas of
     >the cause of such a problem?
     >
     >James Boyd
     >Boyd Broadcast Technical Services
     >Tualatin, OR
     >
     >
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References

   1. http://www.oldradio.com/archives/hardware/SXtips.htm