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Saturday, September 18, 2021

SolderSmoke Goes FT-8 (Briefly, I Think)

Idle hands are the devil's workshop my friends.  I was home alone this week, and kind of ran out of things to do.  I started thinking about all those signals on the FT-8 frequencies that I'd hear when the rest of the band was vacant. You know how it is:  One thing leads to another.  I remembered that Rogier  PA1ZZ had sent me some interface boards.  Soon I was downloading WSJTX.  Then I bought a USB-Serial converter from Bezos.  

I hit a major bump in the road when I managed to destroy the little optocoupler that the interface board used for T/R switching.  No big deal though -- Pete has a simpler T/R circuit that worked fine: 

I even made it a bit simpler -- instead of putting an SPDT relay on the Collector of the 2N3904, I just ran a lead to the PTT terminal on my BITX mic input connector.   This terminal just takes one side of the BITX TR relay to ground on transmit.  With Pete's circuit, the RTS signal from the computer causes the 2N3904 to conduct, in effect grounding the BITX T/R relay. Bob is your uncle.  Building this little circuit was fun. 

I used the 600-600 Ohm  AF transformers on Rogier's interface board.  I scrounged up the appropriate connectors and soon I was on 17 meter FT-8.  After about an hour of casual operating (mouse clicking, really) I'd worked HC1HC, HI8CJG, DK4RL, J69DS, F5NBQ, PT2ADM, 8P6ET, KP4JRS, XE2YWH, F4DIA, EA4R, CO3DK, and HI3MRV.    All this while no SSB signals were heard on the band. I was running about 50 watts to my 75 meter doublet tuned to 17. 

The amount of DX you can work is impressive, but I don't know if I'll stick with this mode.  It kind of reminds me of 2-way WSPR.  I find myself wanting to TALK to the DX stations.   FT-8 doesn't let you do that.  But hey, I am not alone in trying out FT-8.  In fact, one of the very first calls that I saw on my screen was the very familiar KB1GMX.  That is Allison, a true radio genius.  That's a good sign.  So maybe I'll have to give FT-8 more of a chance. 


  1. Welcome to the dark side, SI5351 & FT8!
    Randy, K7AGE

  2. When you put your key in a draw,and push it shut, you'll know you've crossed the line of no return...


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