[Skimmertalk] disabling USB connection

[Pete Smith N4ZR]

Yep, been there, and been doing that for years, Bob - in my setup, PTT 
removes voltage from the active antenna, which opens a relay to the 
whip, and also removes DC from my preamp.  That protects the hardware 
just fine, and in my case, where the transmitting antennas are ~500 ft 
from the RX antenna, and ~200 feet from the RX itself, is quite 
adequate. I asked the question more for the guy whoseSkimmer antenna and 
TX antennas are within 50 feet of each other.

In fact, the RBN Aggregator already does this in software with a "bad 
call list".

73, Pete N4ZR
Check out the Reverse Beacon Network at
http://reversebeacon.net,
blog at reversebeacon.blogspot.com.
For spots, please go to your favorite
ARC V6 or VE7CC DX cluster node.

On 6/23/2013 7:00 PM, Bob Wilson, N6TV wrote:
> On Sun, Jun 23, 2013 at 9:14 AM, Pete Smith N4ZR <n4zr at contesting.com>wrote:
>
>> It occurs to me that one way to mute a QS1R, SDR-IQ or similar receiver
>> might be to open one or the other (or both) data lines in the USB cable.
>>   This probably is 'way too simple - does any of you know if the USB drivers
>> used on motherboards would tolerate this without throwing an error?
>>
> It sounds like you want to mute the data to prevent "images" of your
> transmitted signal from being spotted? It's probably much simpler to do
> that in software (e.g. use a "reject" list to eliminate every variation of
> your own callsign being spotted by the local skimmer).
>
> The real need, of course, is to open or protect the front end of your SDR
> whenever you transmit.  Opening or stopping the USB line will not protect
> your SDR. :-)
>
> Some RX antennas using remote Pre-Amps (e.g. active Rx Loops or short
> vertical whips) provide a way to quickly remove pre-amp power using the PTT
> line on the radio.  That's very effective, and much better than trying to
> do it in software or via USB commands or tricks.
>
> 73,
> Bob, N6TV
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