Add a second FT8 decoder for more QSOs

John, K9EL

For many years, I have operated FT8 using two decoders - WSJT-X and JTDX.  WSJT-X (including the latest version) has been my main FT8 software and the one I almost always use for transmitting.   However, on receive, I run both decoders at the same time.  Windows PC's are very flexible on audio and multiple devices can use the same audio feed at the same time with minimal degradation.

So, why use two decoders?   Although JTDX is built on the same engine as WSJT-X, they rarely decode every station the same and almost always have different signal strength levels.   I like to think that JTDX is a second receiver for FT8.

Here is a great example:

On August 31st, I was trying to work CY9C on 10 meters.  That is a very difficult path for northern Illinois and I was able to weakly decode their signal by aiming my Yagi at 110 degrees - skewed path.   At 181500, CY9C called me and gave me a +03 report while I was decoding CY9C at -24 using WSJT-X.   I was running JTDX at the same time but JTDX did not decode the CY9C calling me.  I returned to them with a report and at 181600, CY9C sent me RR73.  But, I only decoded the RR73 on JTDX!  Their signal level was -18, but nothing was decoded by WSJT-X.  If I had depended on only one or the other, I would not have a QSO.

I merged the two screen shots so you can this capture of both FT8 decoders:

                       JTDX                                              WSJT-X

I cannot explain why they decode differently, but there is a clear advantage to having both decoders running at the same time.

Unless you use the very capable OmniRig software by VE3NEA (https://dxatlas.com/OmniRig/) or have a port splitter, it is not possible to connect both FT8 programs to the same com port, so choose the FT8 software that will be your "main" FT8 program and the one you will use for transmitting.  In the settings for the second decoder, set the radio to "NONE".  The frequency information will not be accurate on your second decoder, but that does not matter as you are logging with your primary decoder.  For Audio, set the Input on the second decoder the same as your main FT8 decoder.  

I hope this setup will be successful for you!

K9EL, Sep2024