The latest version of WSJT-X Improved, from v2.7.1, it is possible to use full duplex, that is listening and decoding at the same time you are transmitting. For satellite operators, mainly QO-100, you can now have full duplex control over your transmission avoiding drifting of your FTx signal.
I did a test with FT4 over RS-44 as I will try to describe here in this post. I’m using Icom IC-9700 and PstRotator for doppler control but the concept is the same if you are using other rigs and doppler control software.
To be able to use doppler control from PstRotator and at the same time control PTT from WSJT-X use Omnirig (setup not described in this post).
For IC-9700 you must set up the USB soundcard in Windows to use both channels (“Kanal 2” in swedish means “2 channels”):
In WSJT-X use the USB left channel from the IC-9700 – left channel is the main band audio.
Set up for Full Duplex Mode in WSJT-X:
Below is an animated GIF when using FT4 via RS-44. Transmitting power is at 0% (zero) so very little uplink power is needed. You see that after every TX sequence WSJT-X is decoding my signal:
And below you see the WSJT-X spectrum as an animated GIF. What you see is my transmitted FT4 signal received in full duplex.
Summary:
The Full Duplex version of WSJT-X improved is working perfect for FT4 via satellite!
If you have problem navigating in Github you can use this direct link and then just choose “Download” and you get all four files for IC-705 and IC-9700.
This is a guide how to work satellites with the Icom IC-9700. When trying to understand the IC-9700 I needed to write down how to use it – so this is how this post was born. Several different user scenarios are explained below.
The IC-9700 satellite memory examples and file can be found here. Please contact us if you see anything that will not work in the following user cases.
Setting up PstRotatorand OmniRig
The PstRotator manual is very good so please read it, very important is the section how to use IC-9700 with PstRotator satellite functions.
The file for OmniRig is delivered with PstRotator and is named IC-9700PST.ini. Do not forget to copy this file to the OmniRig folder.
My settings for OmniRig is like this:
And a typical layout for PstRotator Satellites Tracking is like this:
Case 1: Using IC-9700 stand alone without computer control
Read the IC-9700 Basic Manual section 7 “Satellite communication”. It has all the information you need.
I have tested linear satellites with manual tuning (RS-44) and it worked very good. My uplink TX signal (VHF) was fixed and I tuned the downlink signal (UHF) when needed. The VFO tracking/untracking function of the IC-9700 is outstanding.
Some basic rules I learned from skilled operators:
“Tune the highest frequency”
“Always tune UHF to VHF” – the same as fix the VHF frequency and tune UHF.
Case 2: Using IC-9700 with PstRotator
Once again – first read the excellent manual of PstRotator and the section about satellites and IC-9700. Then – read it one more time!
Some operating hints:
Select the satellite from PstRotator Favorites. Correct frequency, mode and subtone (if needed, for FM) are now set to IC-9700, and the radio goes into Satellite Mode. The filter selection, for example if you have chosen FIL2 for USB, should not be changed from PstRotator.
The first time on a satellite you may need to correct the offset with the +/- and then click Save.
Press the “UP+DN” on PstRotator. Doppler is now adjusted on both RX and TX. You can use the VFO knob on the IC-9700 to tune around on the passband with full doppler control, very nice! Just transmit and you should hear yourself.
If a station you would like to receive, or your own signal, is off frequency it can be good to use the RIT on the radio to adjust RX frequency in a smooth way, without changing the PstRotator settings. Also the PBT (Pass Band Tuning of RX filter) can be good to use during RX.
Case 3: Using IC-9700 as TX with SDR-Console v3 as RX
In this case the IC-9700 is working as the transmitter with full doppler control and SDR-Console with a SDR (or panadapter for IC-9700) as receiver, also with doppler control. Be sure to set the correct band for TX to the MAIN VFO in IC-9700 and do not use the Satellite Mode. Then use the same setup as described in this post.
It is possible to use the VFO knob on IC-9700 to tune the TX frequency.
Case 4: FT4 with IC-9700 and PstRotator
Be sure to use DATA mode settings in PstRotator. Then the IC-9700 is using the filter you have selected for DATA. Then use it just like Case 2 above.
Case 5: FT4 with IC-9700 as TX and SDR-Console v3 as RX
Use the IC-9700 as transmitter and SDR-Console with SDR (or panadapter for IC-9700) as receiver. Be sure to set the correct band for TX to the MAIN VFO in IC-9700 and do not use the Satellite Mode Use the same setup as described in this post.
This is the setup I’m using when running FT4 because I think it gives better control over the QSO than using PstRotator.
This is a memory group file over satellite frequencies for Icom IC-9700 and CS-9700 software. Feel free to use it, change and add, make your own groups etc.
Import the memory file into CS-9700: Note! Be sure that you not overwrite anything in your IC-9700 when cloning and/or importing the .csv file! Make a backup of your current settings!
Mark the Satellite Memory group
Right click and choose import the .csv file
The memories will now be imported to CS-9700
As CS-9700 seems to handle character set different between regions I have created two files. If one does not work, try the other one. Comma separated is working for North America.
This is a simple guide for working FT4 mode via satellite with the help of SDR-Console software, a SDR receiver and Icom IC-705 as transmitter. The IC-705 can of course be replaced by any other radio that can be controlled via OmniRig.
I have also tested this with an ICOM IC-9700 with equal good result.
The “magic” is done by Omnirig. This smart little software can connect several software to one radio at the same time, in this case SDR-Console and WSJT-X.
This guide requires that you have basic knowledge of the following:
WSJT-X and FT4 operation
SDR-Console V3 satellite operation
IC-705 operation (or other radio if you like)
Audio piping between several software
Basic operation with OmniRig
Step 1 – Setup SDR-Console and IC-705 with correct frequency
First you need correct frequency for SDR-Console and IC-705. You can download and use the prepared files from this site. Start SDR-Console and set the downlink (USB) to the satellite you would like to use. Set the IC-705 to the uplink of the satellite, note it has to be LSB-D (LSB with data mode).
Step 2 – Config WSJT-X
Start WSJT-X and config as following:
Rig should be Omnirig and your setup for IC-705
Mode should be “None” to avoid WSJT-X to set the rig to USB-D
Soundcard Input should be the virtual audio from SDR-Console
Soundcard Output should be the IC-705 mic
Step 3 – Start Satellite External Radio in SDR-Console
Now start the “Satellite External Radio” in SDR-Console. Select the same OmniRig radio as in WSJT-X. Select the correct uplink frequency and turn on Doppler correction in External Radio.
Now the magic happens! SDR-Console is starting to doppler correct the frequency of the IC-705 and WSJT-X reads the correct frequency from IC-705 in real time!
In this image you can see External Radio and WSJT-X with correct frequency:
Step 4 – Select correct RX frequency in SDR-Console
Select the correct downlink frequency in SDR-Console and enable Tracking in the Satellite Window for the satellite. Now wait for the satellite to be in your footprint.
Step 5 – Find yourself on the satellite transponder
When the satellite is in your footprint, you need to manually adjust the TX-frequency (at the External Radio window) and RX-frequency, as the SDR-Console software does not have a “tracking RX/TX VFO” function.
Find a free area on the satellite transponder
Turn your TX output to very low
Start transmitting FT4 or use the Tune function in WSJT-X
Adjust TX/RX so that your signal is in your RX bandwidth
Step 6 – Start calling CQ
Now you are ready to start calling CQ and making QSOs! Remember – use the minimum TX power, FT4 is very effective. And be sure not to call over a CW or SSB station.
How to use a 2nd instance of WSJT-X for RX of your own FT4 signal
If you would like to check your own FT4 signal (for testing and learning) it is possible to start a 2nd instance of WSJT-X as receiving only.
Create a new configuration in WSJT-X where Radio->Rig should be set to None and Audio Input should be the piped audio from SDR-Console. Save it to a name of your choice {your_configuration_name}
After you have started WSJT-X for the TX (see above) start a 2nd instance with this command in a cmd window: {path_to_your_wsjtx}wsjtx.exe –rig-name={your_configuration_name}
Now when you TX your FT4 signal the 2nd instance will decode your own signal. See the example below:
Finally, below is a recorded video of a test via satellite AO-73 decoded with a 2nd instance. If you have any questions about this setup please contact AMSAT-SM (Lars SM0TGU) at info@amsat.se
