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Hum on transmitted signal

Al Matthews
Al Matthews Member ✭✭
I received my 6600 M today, and got right to familiarizing myself with it. I made a few quick contacts and I was told that there was hum on the signal. I looked at it on two other transceivers and on both panadapters you could see the hum superimposed on the signal the hum is there in CW, tune, and SSB. I tried a different power supply, all of them Astron linear supplies, and the issue persisted. I even put a scope on the output of the power supply to look for ripple and there was Virtually none. Could this be something about the SDR architecture and the 6600 that I’m not familiar with? Any help would be appreciated I also have a screen issue, and I wonder if this is something that others have observed. In the upper left hand corner of the screen there is a light area, what you might see if you put you finger on an lcd screen. It is there all the time. There is no such abberation on the Maestro I bought to go with the 6600m.
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Answers

  • mikeatthebeach .
    mikeatthebeach . Member ✭✭
    edited June 2020
    Not normal.... Have 6600M here and No Screen/No Hum issues 
    Try a 50ohm dummy load --- Is it RF getting into DC Lines - etc
    Might suspect RF getting into it on Transmit - Ferrite Cores can fix that ! 

    Regarding the screen issue - attach a jpeg so we can see it to comment 

    73 Mike
  • Burt Fisher
    Burt Fisher Member ✭✭
    edited June 2020
    You have the same name as K1LTJ who I knew as a kid 58 years ago and look like him. I have a Flex 6400M. I think we are the only two still alive and active from that group from Norwalk area.
  • mikeatthebeach .
    mikeatthebeach . Member ✭✭
    edited August 2018
    Al, 
     
    Also if you have the Astron Linear Supply too close to the Flex
    perhaps the AC Field of the transformer is causing issues with
    the 6600M with an AC Field from the transformer induced Hum

    If you have a DC Battery in lieu of the AC supply that would eliminate
    that factor as an issue of the hum 

    Mike
  • Bill -VA3WTB
    Bill -VA3WTB Member ✭✭✭
    edited June 2020
    Al, start by disconnecting things from the radio one at a time and use tune button to transmit. Something connect to the radio causing a ground issue.


  • Al Matthews
    Al Matthews Member ✭✭
    edited August 2018
    We're still alive?
  • Al Matthews
    Al Matthews Member ✭✭
    edited August 2018
    Hi Mike, I am using an Astron VS-50m linear supply. It is about 10 ft. from the 6600m. I tried the Astron 50 amp switcher that I also have. No difference.
  • Al Matthews
    Al Matthews Member ✭✭
    edited June 2020
    Good point Bill. I unplugged everything but the ethernet and power connector. (obviously). I then unplugged the ethernet cable, no change. I am running 1 watt into a dummy load.
  • Al Matthews
    Al Matthews Member ✭✭
    edited June 2020
    Here are the pix and a short video of the problems. I have also included a video so you can see and hear the problem. I do appreciate the help and suggestions. Any more ideas on what I might try? 

    Al / K1LTJ







    Here is the picture of the light area that never goes away in the upper left corner of the screen. There seems to be some of this a the bottom center as well.

    image
  • Burt Fisher
    Burt Fisher Member ✭✭
    edited August 2018
    Great video, disconnect the ethernet the M can run without it. It shouldn't help but there is no logical reason for your problem so try illogical solutions. Mike said to try a  "DC battery" I think all batteries are DC but his suggestion is good.
  • mikeatthebeach .
    mikeatthebeach . Member ✭✭
    edited August 2018
    Al,
     
    Saw your video, if you get AC buzz with a Battery you should contact help desk

    Also, the white Flare Up in the Upper Right of the screen most likely
    will not show when SSDR is running. I suspect it is because of more
    pressure in that corner due to mounting or shifting of the Touch Screen

    Mine has a slight White Flare-Up in that area, but not seen when Display is active
    or Booting Up. ( White Flare-Up in left upper Corner is on mine as well ).
    Some may be more noticeable than others is my guess 

    Possibly during shipping this can be aggravated, my guess this can be
    fixed by a mechanical readjustment by Flex if you sent it back to fix the Hum
    Issue

    Maybe a ribbon Cable ground got loose during shipping to cause your Hum Issue
    ( Try with a DC Battery ). If your 6600 goes back, both Issues can be addressed
    with a Help Ticket to Flex.

    73 Mike

  • N4QM
    N4QM Member ✭✭
    edited June 2020
    Does the buzz change character or level if you raise or lower the touchscreen backlight illumination?
  • Wayne
    Wayne Member ✭✭
    edited August 2018
    Looks like at the factory either the touch screen or the backlight were mounted slightly off the correct position then missed during the qc process before it was shipped. You need to open a helpdesk ticket to get an rma and maybe while its there they will verify if the hum you are hearing is due to the rig or your shack environment. Be sure to describe to them exactly how to observe the white you are seeing or they may miss it when they try to make it repeat.
  • K3SF
    K3SF Member ✭✭✭
    edited August 2018
    a 10ft long DC power cable...seems like a perfect place to pickup RF and to have a very large voltage drop....

    the flex input voltage is critical.

    There are some s/w utilities to measure the input voltage...

    see thread
    https://community.flexradio.com/flexradio/topics/voltage-drops-chart

    https://community.flexradio.com/flexradio/topics/flex-meter-v1-2

    http://k5fr.com/DDUtilV3wiki/index.php?title=Main_Page

    these s/w tools will measure the voltage inside the radio

    Paul K3SF







  • Bill -VA3WTB
    Bill -VA3WTB Member ✭✭✭
    edited August 2018
    What is you DC power at the power connector on the Flex while in transmit at a 100w
  • Bill -VA3WTB
    Bill -VA3WTB Member ✭✭✭
    edited August 2018
    Al, I don't think you are going to get any further here, I would open a help ticket tonight.
  • Ken - NM9P
    Ken - NM9P Member ✭✭✭
    edited August 2018
    Try it by transmitting into the XVTR port to rule out any internal RF leakage as well.
  • Ken - NM9P
    Ken - NM9P Member ✭✭✭
    edited August 2018
    You may want to do a factory reset, as per the manual, and see if perhaps the processors glitched when booting up and something got set incorrectly.
  • Al Matthews
    Al Matthews Member ✭✭
    edited August 2018
    Bill, I removed everything one at a time, but the hum is still there
  • Al Matthews
    Al Matthews Member ✭✭
    edited August 2018
    Ken, I tried the xvtr port, but no change the hum is still there. I did a factory reset, but no change. The manual says to hold the power button from the off state until it blinks white. It turned white, but never blinked. I also tried downgrading the software without a change.
  • Al Matthews
    Al Matthews Member ✭✭
    edited August 2018
    I changed the touchscreen illumination Dennis, but it had no effect.
  • Bill -VA3WTB
    Bill -VA3WTB Member ✭✭✭
    edited August 2018
    Did you put in your help ticket yet,,time is wasting.
  • Al Matthews
    Al Matthews Member ✭✭
    edited August 2018
    Yes, I put one in Bill, so I hope to hear from them. I’m not sure if I’m ok with repairing a 5hr old $6000 (with gpsdo etc) Radio. This must be unusual, I have never bought a DOA transceiver in 59 yrs as a ham.
  • Al Matthews
    Al Matthews Member ✭✭
    edited August 2018
    And thanks for all the help everyone has offered. This is a great group.
  • Al Matthews
    Al Matthews Member ✭✭
    edited June 2020
    This is a great group of helpful people, with some great ideas on things to try. Thanks to all of you.
  • N8SDR
    N8SDR Member ✭✭
    edited August 2018
    Al,  have you disconnected the Ethernet cable and tried as well ( didn't see that mentioned) , I'm curious as I have seen some routers and switches which are noisy and i wonder if that is getting into the radio via the cable. If it does away try another cable if its the newer style with the metal grounding around the connector try one without it a standard type 5 will suffice. If it also drops and reappears with another cable then start looking  down the line at the devices which are plugged into the router and or switches including other computers and such. Some of it comes into the network system via the cheap non filtered power adapters they use. Ground loops between the network devices can also cause issues.
  • Al Matthews
    Al Matthews Member ✭✭
    edited June 2020
    Thanks for the suggestion. Yes, I tested with only the power and dummy load connected. The problem was not affected by removing the Ethernet connection.
  • Burt Fisher
    Burt Fisher Member ✭✭
    edited August 2018
    How about a battery?
  • Terry AB2UE
    Terry AB2UE Member ✭✭
    edited August 2018
    Try plugging astron power supply into a 3 to 2 prong adaptor as a test to see if hum goes away.
  • Burt Fisher
    Burt Fisher Member ✭✭
    edited August 2018
    Did you ever fix it?
  • Al Matthews
    Al Matthews Member ✭✭
    edited June 2020
    Yes Burt, Tim has been a great help. It is an intermittent problem, and they will look into it for me. The support with Flex is great.

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