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Unstable HF carrier or smps F6500

Steve G1XOW
Steve G1XOW Member ✭✭
edited June 2019 in SmartSDR for Windows
Hi, looking for other peoples checks / feedback please.

I have found an unstable carriers (looks like SMPS warble) riding from 49.9 to 50MHz (see example pic). It goes progressively more HF then jump back a little and starts again. a bit like an unstable SMPS.

The really odd thing is that the signal is there all the time, and just as loud with no antenna or coax connected to the flex RF sockets....puzzled, what does yours look like please?


I may have a QRM source, but other than the PC (can't turn off for obvious reasons) nothing else is close enough to generate that high level of signal with NO ANTENNA connected. Thoughts?

ps. Large amount of ferrite on the DC cables, and the 240V AC cables, and a EMC mains power filter, and a very substantial station earth bonding to real ground.

Thanks, Steve G1XOW


  • EA4GLI
    EA4GLI Member ✭✭✭
    edited October 2018
    Bose speakers power supply.
  • Tim - W4TME
    Tim - W4TME Administrator, FlexRadio Employee admin
    edited March 2017
    Steve - please open a HelpDesk ticket so I can investigate.  I'll be watching fo it in the support queue.  If Dudley picks it up before I do, have him assign it to me.
  • K5CG
    K5CG Member ✭✭
    edited February 2017
    Not just the PS. Even DC powered they ("Companion 2 Series III" at least) emit RFI.
  • Norm - W7CK
    Norm - W7CK Member ✭✭
    edited February 2017
    I have seen this very same thing on my 6700.  For me, It doesn't appear there all of the time and may even be linked to what is running on a different panadapter. 

    I just brought up 6m and it isn't there right now.  I'll have to play around a little and see if I can narrow down the circumstances.

    I just got it to show up again.  I had 3 pan adapters open with one set on 6m.  Next I just started to change the bands on the other two adapters.  When I changed one of them to 2m, all of the pan adapters changed to 2 meters.  Next, I changed the 2m one back to 40m, and reset the others back to what they were.  Now the one tuned for 6m shows a very large carrier at 50.033 and slowly moving up the band.
  • Norm - W7CK
    Norm - W7CK Member ✭✭
    edited February 2017
    I've now rebooted the 6700 and have tried several times to try to duplicate the problem but haven't been able to yet.   This moving carrier does happen quite often though.   When it does, it seems that there are a lot of other evenly spaced carriers on many of the other bands, especially 17m.   I'll have to keep playing around and see if that really is the case though.
  • Norm - W7CK
    Norm - W7CK Member ✭✭
    edited February 2017
    This is not due to any outside interference.  It appears to be something internal to the Flex.   So far, every time it has occurred, I have been able to get rid of it by rebooting the Flex.   This also takes care of a bunch of other spikes that occasionally appear on other bands.
  • Bob Kozlarek
    Bob Kozlarek Member
    edited February 2017

    This is ironic that this issue came up today. For the past few weeks I’ve been experiencing a similar problem on my 6500, but not near 6M. I’ve had this “phantom” signal drift back and forth from 3.875 – 3.890 throughout the AM Window. Some days it rock solid, and some days it wanders back and forth. This weekend I’d planned to go out and locate it. What leads me to think it’s Flex related is because I can’t hear it on any other radio. This evening I’ll check to see if I see it near 6M. Update and screen shot to follow.

  • Don, VE2HJ
    Don, VE2HJ Member ✭✭
    edited June 2019


    I'm new to the Flex community, and a Flex-6500 user for 2 months.

    While investigating my local 15m RFI whith no antenna connected i notice a variation of the carrier observed on the panadapter. I found that when i disconnected my headset (Mic and Phone) there was a drop of 5 dB on those signals coming from my router.!!!

    Now on 6m i have no observation of unstable signal.

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