Note for Transmitter and Receiver Modifications for the FT-736 and Other Rigs for Microsat Operation

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  1. Before you do any modification, call your rig's manufacturer to see if they have a service bulletin for 1200 baud PSK and 9600 baud FSK modifications. Other sources for this information are the various AMSAT nets, and the AMSAT-BB discussion group on the internet.
  2. In some Yaesu manuals the data in/out jack pins are listed in reverse of what they actually are. The mini-stereo tip is the received data (RD) and the ring is transmitted data (TD).
  3. My 9600 baud modifications are based on a bulletin by James Miller, G3RUH. I expanded on this information based on my own experimentation and from messages from other users.
  4. I received reports that R91 has been mounted in reverse on some production runs, so that the discriminator must be tapped at pin 10 on the RX module's FM scanner board. Yaesu assured me this has never been the case. Although Pin 10, which comes directly from the discriminator, reportedly works for DSP-2232 users, the recommended tap is on R91's side opposite the discriminator, as discussed above.
  5. Pin-outs for the CAT port was in error in some FT-736R manuals and in an old Yaesu "Application Note". The correct pins are:
      Pin 1   Ground
      Pin 2   Serial Data In
      Pin 3   Radio Port Busy
      Pin 4   Serial Data Out
      Pin 5   No Connection
      Pin 6   13.8 volts
    Note that the pins are not numbered sequentially:
                    3       1
                    5       4 
              (rear view of male plug)
  6. This method of setting deviation was suggested by James Miller, G3RUH.
  7. PBLOGNEW.EXE by Patrick, F1TFQ was used to statistically analyze my throughput from my pb.log files for UO-22, KO-23 and KO-25. This file was downloaded from KO-23.
  8. Modification and performance evaluation by Manfred, XQ2FOD. He can be contacted on KO-23 and KO-25.

Article and notes by Howard Sodja, W6SHP. HTML conversion by and feedback to KB5MU.