[Elecraft] [K3] Serial interface noise issues

[Fred Jensen]

On 11/1/2011 9:54 AM, Jim Brown wrote:
> On 11/1/2011 4:51 AM, Thomas Horsten wrote:
>> I guess both of these problems could be down to bad/no screening of the
>> little chip in the dongle, I tried enclosing it and the cable in kitchen
>> foil but with no discernible difference. Any suggestions,
>
> The more likely cause is a Pin One Problem on one or both ends of the
> cable. The only proper termination of a cable shield is to the shielding
> enclosure at both ends.

I had the same problem when using my K2/100 for RTTY.  I had the 
headphones bridged across the audio output feeding the sound card and I 
could hear the polling.  It sounded like a low pitched "rush ... rush 
... rush ..." sort of similar to the ET signal in the movie "Contact" -- 
only not in prime numbers :-)  It was louder when I powered the laptop 
from the mains, almost disappeared on the battery.  It did not show up 
on the transmitted signal.

I switched to the K3 for RTTY, and don't have the problem anymore.

73,

Fred K6DGW
- Northern California Contest Club
- CU in the 2012 Cal QSO Party 6-7 Oct 2012
- www.cqp.org