Monday, June 20, 2022

Winlink Email Using VARA HF


Below is my documentation on how to configure Vara HF for the Yaesu FT-891 and the Icom IC-7300.

UPDATE:  On 10/20/2022 I tried to use Winlink over VARA HF on my 891.  I could not get rig control to work, even though I implemented the same config.  However, I plugged into the IC-7300 and had it working in minutes.  Arrrrg.  All that work on the 891 and now it will be a long debug session.  Although I started with the FT-991, I've documented the 7300 config below (easy)

I wanted to run a Winlink Express app (email application) and use HF radio to send and receive email messages.  The Amateur Radio Emergency Services (ARES) team that I’m on uses Winlink along with its built in standard FEMA forms.  It helps ARES accomplish their mission to support local hospitals, clinics and associated agencies during an emergency.  Using HF setup for sending email during an emergency is appropriate if the affected area is large (no internet for 100 miles).  This is because you can move messages into and out of the affected area using relay stations that have internet service that are 100s or over 1,000 miles away.  For instance, if there was an earthquake in my area, I’m better off trying to get a message to a hub station that is outside of the affected area which could be all of Southern California.  Because of it’s range, HF is perfect for this scenario.  Station to station transmission could be achieved using the lower HF bands as well, or using VHF modes like VARA FM or packet.  I’ve been successful using packet radio from my 5w FT-817 but packet stations are slowly disappearing. 
(click on images for larger)

My goal was to use my Yaesu FT-891 radio because the FT-891 is a perfect 100 watt portable radio for this mission.  I expected it to be a bit more difficult than using something like an Icom 7300 mainly due to the smaller number of people that use this radio and therefore less documentation or examples from others.  A search on Youtube for my exact equipment choices with VARA HF and Winlink turned up very few results.  The results that did come back didn’t have the level of documentation detail needed to get my solution working, they just showed the finished product.  (If you want an intro on Winlink, read my Winlink in a Backpack article.)

It should be noted that I have no idea what I’m doing.  I’ve learned quite a bit more during this exercise and am providing this to remind myself how I set this up and possibly help others through their setup.  If you don’t use my radio or sound-card, hopefully a few things in here will help you sort out how to configure your station.

This posting is to document my configuration that will use  Winlink Express with the Yaesu FT-891 via VARA HF for data exchange.  I’m doing this to help others as well as remind myself how to brew up the special concoction to work.

Exec Summary

I downloaded the VARA virtual TNC modem that runs on the PC, purchased a Yaesu SCU-17 soundcard and then hooked this up to my radio and my laptop running VARA for digital communications.  This configuration works for sending email from my windows laptop running Winlink Express to other stations using the VARA virtual modem software.  I spent a long time playing around with different settings trying to get all of this to work together and have settled on the configuration below that is currently working. I still have a few questions about this configuration that I hope to answer.  I’ll be updating this post as new information becomes available.  


What is it?

VARA is a High Speed software based HF modem based on orthogonal frequency-division multiplexing (OFDM) modulation that is capable of 42 bps Symbol Rate with 59 carriers.  OFDM is a frequency-division multiplexing (FDM) scheme used as a digital multi-carrier modulation method using a large number of closely-spaced orthogonal sub-carriers to carry the data.  The data is divided into several parallel data streams or channels, one for each sub-carrier.  Each sub-carrier is modulated with a conventional modulation scheme (such as QAM or PSK) at a low symbol rate, maintaining total data rates similar to conventional single-carrier modulation schemes in the same bandwidth and is used in applications such as digital video and audio broadcasting, wireless networking and WiMAX.


VARA is designed for operation within a SSB Bandwidth of 2400 Hz using most standard ham radio equipment with a sound-card interface.  VARA provides uncompressed user data rates to 8489 bps at a low  (S/N 16 dB @ 4kHz) and has 17 fast adaptive speed levels.  It’s capable of 8489 bps in “Tactical” mode and 7050 bps in standard mode.  The data link survives the extremes of HF conditions using fixed 42 bps symbol rate per carrier and the FCC single carrier 300 bps cymbal rates are negated by OFDM.  It’s robust and reliable link is maintained under varying propagation conditions, QRM (man made interference) and transmit power fluctuations.


Advantages of OFDM

     Multipath delay spread tolerance

     Immunity to frequency selective fading channels

     Efficient modulation and demodulation

     High transmission bitrates


     Easy equalization

     High spectral efficiency

     Resiliency to RF interference

     Lower multi-path distortion

     This VARA implementation is integrated with the Winlink Express client.

     The VARA virtual TNC modem is free, and only $69 for full tilt performance.


     Assume Winlink is already installed and working using the internet as a message transfer conduit. 

     Assumes you have the Ingredients below and know how to configure them.


     Windows 10 laptop.  I have a inexpensive small Toshiba laptop that I use.

     Winlink express

     VARA 4.6.2 (virtual TNC software)

     Yaesu FT-891 HF radio, the perfect 100 portable rig.

     MFJ-939 Automatic antenna tuner.  This is the perfect match for the FT 891 because it’s powered and controlled by the radio.

     Yaesu USB interface unit SCU-17 (for some reason Yaesu doesn’t call it a sound card).  This is the smallest sound card that I’ve found and you save $$$ because it comes with the custom cable needed to feed the FT-891. 

     Antenna for your band (my station was using a Cushcraft R8 vertical)

     USB cable from PC to SCU-17 (comes with the SCU-17)

     USB cable from PC to Yaesu FT-891 (used for rig control), provided by you.

     Do not buy the Yaesu cable CT-62.  It’s not needed.  You’ll use the USB direct to radio for CAT control and you need the tuner port for the ATU if you have one.


Installation and Configuration

USB driver for the SCU-17

  1. You will need to install the USB drivers for the SCU-17.  It’s possible that  the correct drivers would be installed on Windows 10 by just plugging in the unit but they recommend downloading and installing the drivers first from Yaesu HERE.  This enables a couple of comm ports to be used for mic and speaker to the radio from the laptop.

  2. Attached the USB cable from the SCU-17 to the PC

  3. Open the “Device Manager” application on the PC

  4. Scroll down to the “Ports (Com & LPT) and expand it.
    It should show a minimum of two additional comm ports:
    One labeled “Silicon Labs Dual CP2105 USB to UART Bridge: Enhanced COM Port (Comx)  [where x is the com port number]

    One labeled “Silicon Labs Dual CP2105 USB to UART Bridge: Standard COM Port (Comx)  [where x is the com port number]

Install & Config of  VARA

Download and install VARA modem HF software from HERE.  The installation is pretty easy, just run the installer, use the defaults.

The config is the same for the FT-891 and the IC-7300 except for possibly the sound card drive level.

Configure VARA app

  1. Start the Vara HF app
  2. Choose Settings, then VARA Setup
  3. Enter your callsign
  4. Close that config
  5. Choose Settings then SoundCard
  6. Use the pull-down for the selection of “Device Input” and select “Microphone (USB Audio CODEC)”.  NOTE: If all you see are Comm ports then the sound card drivers are not installed.
  7. Use the pull-down for the selection of “Device Output” and select “Speakers (USB Audio CODEC).  NOTE: If all you see are Comm ports then the sound card drivers are not installed.


You should now see the VARA app waterfall show that it’s receiving from the radio and the “audio Input” needle should be in the green.  If it’s not, try adjusting the RX level on the sound card.  If it’s still not receiving, the drivers didn’t get installed correctly for the sound card or you didn’t select the correct Device Input.  If this is not working, no digital mode will work.


Configure Winlink to use VARA on FT-891

It’s assumed that you have Winlink installed and that you can send and receive messages via “Telnet” (internet connection).  You’ll need to have created an account on Winlink and tested that it works.  The team scrubs old accounts off the servers after a certain amount of time.  (as me how I know).

  1. Open Winlink Express
  2. On the right hand side of of the screen, use the pull-down and select “Vara HF Winlink”
  3. Click Open session.
  4. If you’ve selected Vara HF Winlink it should fire up the Vara app (unless it’s already running).

In the “Vara HF Winlink Session window”

  1. Choose “Settings” then “VARA TNC setup”
    1. Use the default for the TNC host
    2. The “Virtual TNC Command Port: defaults to 8300.  This should match the port in the vara app if you look in the settings VARA setup.
    3. “VARA Modem location:” should match the drive path and executable that the app is installed to.  The default is “C:\VARA\Vara.exe”
    4. Click Update button at the bottom if you made changes.

  2. Choose “Settings” then “Radio Setup”

    NOTE:  You may have to play with these settings a bit depending on the nuances on how the COM port drivers loaded up on your PC.
    1. Select Radio Model “Yaesu FT-891” or IC-7399

    2. Select USB (not USB digital)  (not sure why)

    3. Radio Control port should be one of the higher number COM ports.  For me it’s COM4 (an “enhanced” port.)

    4. Set the “Baud” rate to the rate setup on the radio in “Configure the FT-891” below.  For me, I set the max on the radio to 38400 and the same goes here.

    5. Check “Enable RTS”  Not doing this won’t kick off the transmit adding to your frustrations :)

    6. For PTT Port (Optional) select “Serial Port to Use “FT-891”. 
      Yes, I know this isn’t a serial port but just roll with it. 

    7. Choose “Update” button.  This will cause the window to reload.

Configure the Yaesu FT-891 Radio

The following settings were made on the Yaesu FT-891. 

I was told to use SSB, not DATA for Winlink and to force the radio to USB so one of the things you do in the settings is force upper side band all the time, even for 40m and below (default is auto).

NOTE:  Some of these settings will make the radio unable to use SSB mode unless it’s undone.  I’ll note that below.  Also, the menu settings below are accessed by using a long-press of the “F” button on the front panel.

  1. Menu 05-06 CAT RATE (set to same as winlink VARA setup 6d above.  I chose 38400, max speed.

  2. Menu 05-07 CAT TOT to 1000msec

  3. Menu 08-01 DATA MODE PSK (I don’t think this makes a difference since we aren’t using DATA mode.)

  4. Menu 11-05 MIC SELECT: set to “REAR”
    NOTE:  This disables voice input using the standard mic and uses the data input on the 6 pin round plug that you have from the sound-card to the radio.
    Change this back to “MIC” for normal voice operation.

  5. Menu 11-07 SSB BFO: set to USB.  Default is auto.
    NOTE: This forces all SSB modes to use upper sideband (even on 40m), which I’m told to we need to use.
    Change this back to “AUTO” for normal voice usage.

  6. Menu 11-08 SSB PTT SELECT Set to “RTS”, but “DAKY” also works.  Not sure why.

  7. Menu 16-03 HF PWR (set to the power output you need).  If in the field, power to 100 and then test by backing off to 50 or less and see if you can still connect to the winlink station.  This can be a high duty cycle mode which could toast the finals :)

  8. Menu 16-07 SSB MIC Gain should be set to 50 by default. 

Configure Winlink to use VARA on IC-7300

I pulled the following images from Yacht Zen Again article.  The 7300 setup took about 5 minutes and just worked.  The only thing that is different is the config for the radio config on the Winlink Vara screen.
  1. Install Winlink (The config is very basic and there are lots of references on how to do that.)

  2. Install Vara (see above)

  3. Install the 7300 USB driver (located HERE on the iCom support page)

  4. Configure 7300 but you don't have to.  The 7300 has a built-in sound card and the  winlink software does it for you. :)

  5. Configure the Vara application just like the 891 (above) using defaults

  6. Open Winlink Express

  7. On the right hand side of of the screen, use the pull-down and select “Vara HF Winlink”

  8. Choose "Vara HF Winlink, next to "Open Session" button.

  9. In Winlink, click Open session.

  10. If you’ve selected Vara HF Winlink it should fire up the Vara app (unless it’s already running).
    1. NOTE:  You may have to play with these settings a bit depending on the nuances on how the COM port drivers loaded up on your PC.

  11. In the “Vara HF Winlink Session window” - Choose “Settings” then “Radio Setup”
    1. Select Radio Model “Icom 7300"
    2. Icom Address 94
    3. Select USB digital
    4. Radio Control port should be one of the higher number COM ports.  For me it’s COM4 (an “enhanced” port.)
    5. Set the “Baud” rate to the rate to 9600.
    6. Leave “Enable RTS”  and Enable DTR unchecked.
    7. For PTT Port (Optional) select “CI-V”.
    8. Choose “Update” button.  This will cause the window to reload.


All configuration is now complete.  Now it’s time to test.

  1. Put an email in the outbox.

  2. Ensure the USB cable from the PC to the radio USB connection is plugged in.
    This is used for CAT control.

  3. Ensure that the USB cable from the laptop is plugged into the SCU-17
    (If the laptop is powered on, you should the “Power” light on the front of the SCU-17 should be lit red.

  4. Ensure that data cable from SCU-17 to radio is plugged in.
    If this is working, then the audio input meter on the VARA app should be moving.  Verify that when you turn off the radio or adjust the volume control down on the SCU-17 that the needle drops to the left peg.

  5. Ensure the radio is tuned for the antenna.  This is important to reduce the SWR on the transmission.  The better the match, the lower the heat on the finals.  You can verify SWR by observinig the radio SWR meter (when set to SWR) and sending a CW tone out or SSB voice (if you put setting 11-05 back to “MIC”.  I suggest leaving the radio meter in SWR mode during normal operation as you change frequencies to ensure nominal operation.  The radio will protect itself and shutdown if SWR gets too high.

  6. Open Winlink Express

  7. Choose “Vara HF winlink” from the list of options on the upper right.

  8. Click the “Open Session” menu item

  9. Click the “Channel Selection” menu item.  This will bring up a list of channels that you could use.  Double click on an appropriate station / band / channel. 
    If CAT control is working correctly, the frequency set on the radio should match the “Dial Freq” displayed on the session dialog.

  10. Listen for traffic.  If the frequency is not busy, run your antenna tuner to ensure a best match.

  11. Click the “Start” menu item.
    1. This should kick the PTT on the radio and start transmitting. 
      It’s helpful to have the meter set to “PO” the first time to verify that the radio is actually sending at the desired power level.  Set it back to “SWR” to monitor SWR for normal operation.

    2. The first time you do this, look at the power meter on the radio and adjust the tx volume on the sound card so that you see the power bar moving  a bit on the top end of the display.  If it’s just pegged on the display then it’s probably overdriving the output.

If everything worked correctly, you should have sent or received email.  If it didn’t go correctly you aren’t the first person to have an issue.  I dorked with the radio for over 8 hours trying to tease apart the right settings.  If you are running with my configuration, double check your settings.

a)    If the PTT isn’t working (radio is not going into transmit mode), check the CAT setting for the COM port you selected in Winlink Session dialog, Settings, Radio Settings.  Try a different COM port.

b)    Assuming the radio is clicking into transmit mode, (red light on the display is clicking on) look at the power output.  Ensure you are getting RF out.  If the bar isn’t moving, check that menu 11-05 is set to “REAR”. 

c)    If the PTT is tripping, check the SWR.  If it’s too high, the radio RF will back off to protect the radio and also give you a warning.  Use an antenna tuner to improve your SWR situation.

Test Results on 891

In summary, once I got my configuration working it worked well and was reliable.  I sent several email messages to my home account, sent a message back and used two different bands. (test message is below).  I’ll continue to test, but this is what I have so far.  Messages were sent using 20m and 40m bands, with the 20m test having the worst signal to noise ratio of the tests and it still worked.

     XE2HS Node in La Paz - 100 watts  free version
I used a station in XE2HS La Paz Mexico on 30m (~1,100 miles from my station) at night and got a data rate of 180 bits per second send and received using the unlicensed version of VARA.  The report basically said 420 bytes/minute. 

     KO0OOO station located in Las Vegas 100 watts,  40m at night  free version
I netted a data rate of about 180 bits per second up and down  (unlicensed VARA), with 488 bytes/minute.

     KO0OOO station located in Las Vegas 50 watts,  40m at night free version
Performed the same as 100w test.

     KO0OOO station located in Las Vegas 50 watts,  40m at day PAID version
Transmit of almost 600 bps, and showed 982 bytes/minute on a message send.
RX peak of almost 450 bps, and indicated 683 bytes/minute on message received.

     EM1OCJ station, 1,800 miles away, 50 watts, 20m during day on PAID version
Transmit and receive of around 150 to 800 bps and throughput of 821 bytes/minute.

     W5WK station, 1,800 miles away, 50 watts 20m during day on PAID version
Had a low to medium signal to noise ratio (sometimes -16 db) and was difficult to hear by ear compared to thers. Up to 180 bps receive

The net/net is that this is a viable method to send email over a long distance to get message traffic out of your area.  The message payload was pretty small (the log file for one of the transfers) but more than usable (see below)


  1. Do digital modes like VARA and fldigi need SSB to work?  I ask because I tried the “Data USB mode” and it didn’t work?  I’m assuming they needs the wider bandwidth???

  2. I’m still a little confused about 11-08 (PTT Select) setting means.  RTS and DTS seem to both work.

  3. Why does everything digital (fldigi and VARA) both require USB.  This introduced a kink that required me to figure out how to force USB all the time for SSB mode.

Notes & Errata for FT-891 config

There are a few oddities about my config.

  1. The Yaesu SCU-17 is supposed to connect to the rig for rig control.  What’s odd is that it would plug into the same port as the antenna auto-tunner.  If it did work, you’d have to run the ATU manually.

  2. The FSK and PTT lights on the SCU-17 don’t do anything.

  3. I noticed that if I unplug the USB connect while the radio is on, it kicks on transmit and stays that way!  It also puts the radio into some odd error mode because when I powered off and back on the red transmit light blinks.  To fix that, remove the power connect from the back of the radio.

  4. I noticed that when starting winlink on the PC with the radio on, it kicks in transmit and it stays that way, and I have to power off.  See issue above to fix if blinking red transmit light on FT-891 comes on when you turn the radio on.  :(

Reference, Acknowledgements, Attributions

     Thanks to Bill, K1CT for helping with some key points that I needed to figure this out.

     VARA description and OFDM spectre image via slides from Jose Alberto Nieto Ros, EA5HVK

     Additional documentation can be found HERE.

     Winlink In A Backpack article shows another way to do Winlink via packet and explains a little more about how Winlink works.

     The configuration images came directly from Yacht Zen Again article.  After trying to get the 891 to work (rig control wouldn't work), I switch to my 7300 and because he did such a good job documenting, I was up and running in 5 min.  Uggg.  7300 rules.


Sample Message

this is just a test


The below is the log from the XE staton

*** Winlink Vara Connection to XE2HS @ 2022/06/20 05:22:08  USB Dial: 10127.700

*** Station Bearing: 144,  Range: 1186 km

RMS Trimode La Paz MX

N1CLC has 1438 daily minutes remaining with XE2HS (DL44UD)

Sessions for users running unregistered versions of Vara are limited to 10 minutes.


;PQ: 79680820

CMS via XE2HS >

   ;FW: N1CLC

   [RMS Express-$]


   ;PR: 18495858

   ; XE2HS DE N1CLC (DM12KX)

   FC EM TDQM08HP90Y9 1013 629 0

   F> 71


*** Sending TDQM08HP90Y9.


*** Completed send of message TDQM08HP90Y9

*** Sent 1 message.  Bytes: 648,  Time: 00:47,  bytes/minute: 826


*** --- End of session with XE2HS at 2022/06/20 05:23:40 ---

*** Messages sent: 1.  Total bytes sent: 648,  Time: 01:32,  bytes/minute: 420

*** Messages Received: 0.  Total bytes received: 0,  Total session time: 01:32,  bytes/minute: 0

*** Disconnecting

*** Disconnected from Winlink RMS: XE2HS @ 2022/06/20 05:23:47

*** Session: 1.7 min;  Avg Throughput: 462 Bytes/min;   1 Min Peak Throughput: 462 Bytes/min

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