[amsat-bb] SatPC32 with the FT-818nd

Loren M. Lang penguin359 at gmail.com
Mon Apr 6 05:44:44 UTC 2020

I recently tried using SatPC32 for CAT control of my Yaesu FT-818nd rig for
automatic tuning during a pass of the XW-2B linear transponder satellite.
The radio appears to be just a minor hardware refresh of the FT-817 and
FT-817nd so I have it configured to use Yaesu FT-817 in the radio control
settings. My CAT control interface is using a U5 Link which connects to the
accessory port on the back of the radio. Inside the box, it is just an FTDI
chip. It is set to the baud rate 38400. I have successfully been using this
box with both Ham Radio Deluxe and N1MM for various other controls.
However, I had an issue with SatPC32 not making all of the correct

>From what I can tell, it is dropping commands. The radio was only partly
configured correctly such as setting the USB/LSB modes on VFOs A/B. It was
not adjusting the frequency. I had the CAT delay set to the original value
of 70 ms and tried increasing it. At 180 ms, it was still having issues,
but I finally bumped it up to 300 ms and the radio started responding
correctly. I then saw it tuning both the TX and RX VFOs as needed
throughout the pass. However, at this delay, it spends a noticeable amount
of time in the TX VFO before it updates the frequency and, if I'm not
watching carefully, will press the PTT on only to have it jump to the RX
VFO to transmit. It also means more time where I won't be hearing the
incoming signal if someone else is talking.

Are there any recommendations for improving this situation or could I
possibly have a bad (cheap Chinese clone?) FTDI chip that is limiting the
rate that commands can be sent? I have not had any issues with HRD or N1MM,
but I expect they are sending commands at a lower rate since it's not a
constant Doppler shift. Anyone else have a solid FT-817/818 setup?

- Loren

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