[aprssig] RE: ICOM 706 MKii G Packet experience.

[Andrew Rich]

Found it - Switch mode power supply noise


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Andrew Rich VK4TEC
vk4tec at people.net.au
http://www.tech-software.net


  -----Original Message-----
  From: Andrew Rich [mailto:vk4tec at people.net.au]
  Sent: Sunday, 25 November 2007 12:16 PM
  To: Aprssig
  Cc: ozaprs
  Subject: ICOM 706 MKii G Packet experience.


  Gudday

  I thought I would share this experience - others may be able to help.

  I bought a KPC3 for 1200 baud to use outboard with the ICOM 706 Mk iiG

  Seemed to work well enough - using the "data" port on the ICOM 706. I
seemed to be copying most packets on ISS and PCSAT.

  I then migrated to AGWPE sound card and I noticed that it was not copying
packets 100%.

  I had a look on the Sound Card tuning aid and I saw something odd.

  It looked like 1200/2200 but was sort of riding on a low frequency sine
wave, in that the packet tones where not symetrical about zero volts.

  OK, time to drag out the CRO. Sure enough saw the same thing on the CRO.

  Time to try something different - the "phones" connection on the front
panel - perfect nicely balanced packet.

  Fiddled with the 9600 / 1200 baud lines and settings in the ICOM 706. Not
much joy.

  Before I dig deeper (service manual), anybody seen similar ?

  I wondered why my SATGATE was not hearing as much.

  Seems the outboard TNC was more tolerant of the mucked up waveform ?

  Cheers



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  Andrew Rich VK4TEC
  vk4tec at people.net.au
  http://www.tech-software.net


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