Splatter TX on 6500

  • 2
  • Problem
  • Updated 2 years ago
  • Solved


Looking for ideas about what could be causing such a bad transmit signal?  I got a complaint from another ham that I was splattering while using DAX and WSJT-X, the SmartSDR display was covered up so I didn't even notice it.  This is what my signal looks like no matter whether DAX is running or not.  This is a screen shot from a TUNE from inside SmartSDR.  I get the same if I manually key, if I transmit from WSJT-X, etc.
Photo of Keith Schlottman

Keith Schlottman

  • 16 Posts
  • 2 Reply Likes

Posted 2 years ago

  • 2
Photo of Keith Schlottman

Keith Schlottman

  • 16 Posts
  • 2 Reply Likes
Official Response
Here's an update.  I think Tim did correctly identify the primary culprit as being excessive common mode currents.
I've added some ~1/4 wavelength counterpoise wires to the ground post on the back of the rig, and also added choke baluns in line with the antenna on the transceiver end.
This seems to help a lot - where the original spikes were as high as -70dB on the vertical scale in SmartSDR, they are now down around -90 to -95, which is fairly close to what I see driving into a dummy load.
I'm enjoying the process of trying to refine it to the best possible result so still have more tests to run.  But the majority of the problem seems to be solved at this point and hopefully my signals are a bit less obnoxious to others on the bands.
By the way I never thought this was possibly an issue with the Flex itself, which is why I posted it to the forum instead of as a support ticket.  I sure appreciate the community support!