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Yaesu FT-991 Winlink Express | Mark Dallner
There seems to be an issue with documentation with/for using the SCS Pactor modems and RMS or Winlink Express. Last update is 02/08/2020 02:23 UTC

Information on this page will be updated as I learn more.

There are videos showing the connection process with none how to set up WinLink for Pactor Sessions.

There are plenty of instructions & resources on setting up the connection between a computer and the FT-991a with a USB cable handling all comms. They will not be repeated here.

You may find that adding good RFI chokes on all cables, both ends and sometimes in the middle, will reduce RFI. ALWAYS follow good engineering practice in grounding & bonding.
Your mileage will vary. I offer this as a resource. You are responsible for your station operation in a safe and responsible manner.

Here is what I have found

Station configuration:

FT-991a, LDG-YT-1200, Radio Wavz inline RF isolation transformer and a Comet CHV-5x with the L3.5 coils added. I removed the 21 MHz coils. And a SCS PTC-IIIusb

I used to have the original MFJ-1708 with SDRPlay 2 in my station setup. I removed it because I was not using it very much. The SWR was excessive on 40 & 20 meters up until I removed these two items. Now the SWR can be adjusted to >1.3:1 according to the meter on the FT-991a. And that is mighty fine...

Computer is a Windows 10 box with 16 Gigs of RAM and a 1 TB HD. Still a spinner.

Settings for the FT-991a that are not default

27: Time Zone -6
28 GPS/232C SELECT; 232C
29 232c RATE: 38400 bps
31 CAT RATE: 38400 bps

In the F M-List settings
DT Gain 50 Default Setting (Had been set to 45.)
WIDTH 3000 HZ (page 52 in the Manual)
A note on WIDTH, I ended up resetting my FT-991a and forgot to set the WIDTH to 3K.
It is at 2400, currently, and seems to be functioning just fine.

The WIDTH setting is band specific. Change Bands, check the WIDTH setting.

RF output 45 watts to connect to the stations that are on my Favorites List, KA0NPJ, KC0TPS, KC8YJJ, ABODK & KD7UHR (VARA)

RF gain turned all the way up and Squelch open.

In WinLink Express Pactor Session:

TNC Setup

TNC PTC-IIusb, (I have the PTC-IIIusb)
TNC Serial Port Com 7, (my compooper)
TNC Serial Port Baud Rate: 38400, (Make sure the com port setting in Windows matches?)
PSK Level 450
FSK Level 350 ( still working with these levels)
TX Delay (milliseconds) 30
Mac Pactor Level 3

Radio Setup

Select Radio Model Yaesu FT-991/A
USB radio button checked NOT USB Digital
Serial Port to Use: Com5, (Enhanced Serial Port on my compooper)
Enable RTS checked
Enable DTR checked.

Make sure you don’t have any DSP or noise reduction enabled on the 991A. The modem has very powerful internal DSP and you don’t want to double up.

And one final note on ALC meter reading, It is in the RED +2. When I turn it down so that it is below the RED zone, I do not get connections.

Got feedback from Gary Wood of Farallon.US. Don’t worry about the ALC reading. The Pactor signal is totally different than a SSB or CW signal and the ALC reading is meaningless.

And one item that helped was I re-flashed the firmware on the SCS PTC-IIIusb.

It was brought to my attention to update the propagation tables on a regular basis under channel selection. I do this each time I bring up a session, VARA, Pactor, ARDOP, out of habit.

There is an interesting issue of my radio needing to be fully reset to get Pactor to work again. Attempting to better log what and when I change settings. Then I can see what causes the failure to connect via Pactor.

Thank you to the Winlink io group, Gordon Gibby, KX4Z, Gary Wood, at Farallon.US & Howard Evans, W6IDS for on going conversations and encouragement. Always great to have connections in the HAM community!