[App_rpt-users] Loosing TX

[Geoff]

On 02/10/2014 08:34 PM, Doug Crompton wrote:
> Another thing to consider on the DMK is RFI. They are very susceptible 
> to it especially higher power HF but be aware that any RF could cause 
> problems. I have had this happen at two different locations. The fix 
> was ferrites on the leads in and out. One on each lead worked for me 
> but more may be necessary depending on the severity. You can also wrap 
> multiple turns through a single ferrite if they fit.
>
> This shows up a a locked interface and usb error messages that in my 
> case specifically said EMI? It might not always catch that it is an 
> EMI problem though so other errors might indicate the same thing.
>
> Since the DMK is nothing more than a fancy USB sound FOB I suspect any 
> FOB might have this problem. Lead length both audio and USB would also 
> be a factor.

Agreed.

I am curious, though, what voltage is sent back to the USB buss from the 
device.
My reasoning is, that in -my- case, when this happened, I noticed that 
if I pulled the USB cord, let it set for 15 or 20 seconds, then plugged 
it back in, the green light lit up, and as soon as it Transmitted, that 
URI died, again.  Shutting down the machine, to the point of letting the 
caps discharge, etc, then bringing everything back up, plugged in, all 
worked flawlessly...

until, at least, I RF'ed the system again with HF signals from 75 and/or 
40m.... ~sigh~

73 = Best Regards,
-Geoff/W5OMR

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