Flex Control RF Problem & Fix

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  • Question
  • Updated 4 years ago
  • Answered
I got my new Flex Control Knob on Friday and was excited to give it a workout during the contest this weekend. After working through the normal connection problem with a new device and setting up the buttons the way I wanted everything was working fine.

I later found that any time I transmitted on 15m with my vertical the Flex Control Knob would stop working. Reboot the computer to get it working again but only until I transmitted again.  I was not impressed and/or looking forward to a lot of playing around to solve this.

Has anyone else had this problem?

Thankfully, there was a solution!

I figured the problem was a problem with RF getting into the Knob or computer. I just happened to have a heavy snap on  choke,  so I wrapped the cord from the Flex Knob around it 4 times, at the USB connector end & snapped it closed. I was happy to find this has solved the problem for me.

Maybe this may be of help to someone else.

Future considerations, some thoughts:

Many devises I have purchased for connecting to my computers have chokes attached on there cables and they are not designed for use in a ham radio station. Considering this, I'm surprised that the Flex Control Knob does not have a choke installed on it's cable.

Maybe, even better, a wireless bluetooth Flex Control Knob.. eliminate the wire.. would make is easier to connect to a laptop or tablet as well as move from one computer to another.
Photo of Ken - VE5KC

Ken - VE5KC

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  • Glad it was and easy fix.

Posted 4 years ago

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Photo of Takeshi Yamada

Takeshi Yamada

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FlexControl has a ferrite core inside - put on the USB cable! 
I had the same problem RFI thru USB that requires reboot, but in my case it was the rotator controlled by PC with adapter.   I put chokes to USB cables at both side and controller side of rotator cable that is likely the most probable cause of RFI as it along with coax more than 100 feet.  I suspect any RFI makes overflow the buffer of serial IC - just my guess, though.
Anyway with ferites and appropriate antenna matching, so far I am free from RFI.

73 de JI1BNU
Ken Yamada
(Edited)