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SWR Changes while in QSO with Tuner

Ken Golubski
Ken Golubski Member ✭✭
edited March 2020 in Maestro
I don't understand why I am seeing the SWR change while in a QSO. I am using a Buddi-Pole antenna set up as a dipole. In either SSB or CW portions, I can tune to a 1.5 or less. Howerver as I'm sending CW or chatting with SSB, all of a sudden, I see the SWR shoot up to max in red. I have to hit the tune button again to get it back down.
Any ideas ?
Thanks.

Comments

  • AH0U
    AH0U Member
    edited March 2020
    Not familiar with that antenna but is it possible it is heating up as you use it and shorting out or changing its match???
  • RFord
    RFord Member ✭✭✭
    edited March 2020
    I would also suspect feedline, connectors or antenna...
  • Ken Golubski
    Ken Golubski Member ✭✭
    edited March 2019
    No, not changing the match. Running barefoot at 100W.
    Thanks.
  • Ken Golubski
    Ken Golubski Member ✭✭
    edited March 2019
    I will take a closer look at connection when daylight returns.
    Thanks
  • John W9KXQ
    John W9KXQ Member ✭✭
    edited March 2019
  • John - AI4FR
    John - AI4FR Member ✭✭
    edited July 2019
  • Bill W2PKY
    Bill W2PKY Member ✭✭
    edited March 2019
    Something in the FLEX Tuner is heating up. This happens to me on 160M. A lot depends on the load characteristics. If very low impedance can cause parts to heat up in the tuner. Changing the feed line length may help. 
  • Ross Lambert
    Ross Lambert Member ✭✭
    edited March 2019
  • Bill W2PKY
    Bill W2PKY Member ✭✭
    edited March 2019
    Add some more coax to the transmission line so the tuner is looking into a better [lower] SWR. 
  • Ross Lambert
    Ross Lambert Member ✭✭
    edited March 2019
    Tried that. No difference

  • Ross Lambert
    Ross Lambert Member ✭✭
    edited March 2019
    Ken, how much power are you using?

  • Bill W2PKY
    Bill W2PKY Member ✭✭
    edited March 2019
    What band are you on and how much coax did you add?

  • Neil D Friedman N3DF
    Neil D Friedman N3DF Member ✭✭✭✭
    edited March 2020
  • Ross Lambert
    Ross Lambert Member ✭✭
    edited March 2019
    it doesnt matter what band.but mosty happens on 80, 40, 30 mostly
  • N8AUM
    N8AUM Member ✭✭
    edited March 2020
    Has it worked ok before or is it a new setup ?  
  • Mike-VA3MW
    Mike-VA3MW Administrator, FlexRadio Employee, Community Manager, Super Elmer, Moderator admin
    edited March 2020
    I have seen this happen on my HF mobile station.

    After lots of work, it was determined that RF was coming back in on the surface of the coax.  When this happens, it looks like an increase in reflected SWR as the reflected voltage rises.  When this happens, the tuner sees the increase, and therefore the atu wants to tune.

    The fix for this is to add some Mix 31 or Mix 43 chokes on the feedline at both ends of the coax (antenna and radio).  This will provide a high impedance for the common mode currents.  

    This document does talk about common mode currents and how to fix them.  http://www.yccc.org/Articles/W1HIS/CommonModeChokesW1HIS2006Apr06.pdf

    I hope that helps.  Mike 
  • Mike Smoot
    Mike Smoot Member ✭✭
    edited March 2020
  • Ken Golubski
    Ken Golubski Member ✭✭
    edited March 2019
    This is a new radio and setup.
    Thanks
  • Ken Golubski
    Ken Golubski Member ✭✭
    edited March 2019
    When I first put the antenna up (it's very portable) I had a 1 to 1 at 7.150.
    However, I did move the antenna on it's tripood a tad, so that probably changed it a bit.
    Right now, it's over 2.5 on 7.191 and will tune to 1.1 to 1
    Thanks
  • Ken Golubski
    Ken Golubski Member ✭✭
    edited March 2019
    Sounds like a good idea. I will try that.
    Thanks, Michael !
  • Ken Golubski
    Ken Golubski Member ✭✭
    edited March 2019
    Interesting. I do make it tight. I will loosen it tomorrow because today is kind of busy.
    Thank you !
  • Tim N9PUZ
    Tim N9PUZ Member ✭✭
    edited March 2019
    I believe the Buddipole antenna is rated for 250W.
  • Mark_WS7M
    Mark_WS7M Member ✭✭✭
    edited March 2019
  • Mike Smoot
    Mike Smoot Member ✭✭
    edited March 2019
    The plug-and-play feedline that Buddipole supplied with my antenna kit has a substantial RF choke built into the antenna end of the line, just prior to the mini-banana plugs. Adding more ferrites at both ends further improved my setup.

  • Mike VE3CKO
    Mike VE3CKO Member ✭✭✭
    edited April 2019

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