flexcontrol rf issue

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  • Updated 4 weeks ago
 Recently I've been having an RF issue with my Flex VU5K. When I'm running FT8 with my K3 that is near my FlexControl I lose the connection between the Flex radio and FlexControl. The only way I can get it back is to reboot my PC.
  This only happens when I use the K3 on 20m. I know it's an RF issue, but it doesn't effect anything else in the shack. It happens on 20m mostly  FT8 with 70 watts or more. The only way that I know how to pick up the FlexControl is to reboot the PC. Does anyone have any ideas on how to do this without a reboot.

 Here's what I've done so far.... 

Re-did ground system, including a new ground rod.

Moved the FlexControl and cabeling as far away from the K3 as possible.

Added some Ferrites to FC cable

Tried to unplug the FlexControl USB and re connect

Powered cycled the Flex Radio and re loaded the software 

Any ideas to try?

73 Jeff kb2m




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Jeff Griffin

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Posted 4 weeks ago

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Dudley - WA5QPZ, Elmer

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Jeff,

Is your computer tied to the same common point ground as the K3?  Windows is flagging that port with a non-functional device and disabling the port,  which is the reason the computer needs to be rebooted..    Unless the antenna is close, many times it is common mode RFI from that antenna,   common mode choke can help on the outside of the shack ..  Just a few thoughts.  

-Dudley
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Jeff Griffin

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 Hi Dudley. This doesn't make any sense but this all started when I upgraded the K3 from a serial interface to a USB. When it was serial it was going to a 232 to USB dongle anyway, so what's the difference. I had some other issues in the shack  from RF but was able to fix all but this by reworking the ground system. Should I try grounding the computer chassis directly to the radio ground system?

 Before this started I had zero RF issues on any frequency. And now the only device connected to the computer that has any issues is the FlexControl, other devices are an az-el sat rotor controller, remoterig, IC-9100, etc. All other USB connected devices are not failing....

73 Jeff kb2m
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Dudley - WA5QPZ, Elmer

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Your serial port most likely did not have a direct chassis ground as the USB cable does,  pull the USB cable from the computer end, to see if the issue goes away ..   I would check with a voltmeter between the USB ground and the computer chassis, your radio is grounded better than the AC safety ground..    Just my thought.. 

-Dudley
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Jeff Griffin

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Issue resolved. I moved the FlexControl cable rerouting it to make the trip as short as possible. I also tightly coiled up the extra cable in a tight loop. It is now RF proof. I must say the FlexControl is the most RF sensitive device I have connected in my shack. There are 5 other USB devices connected to the same computer that have/had no issues. If I haven't been using it for over two years without any issues in two places, I would of sent it back for being defective....

73 Jeff kb2m
(Edited)