[Elecraft] K3 Noise Floor 160m - 75m

[Paul Christensen]

> Holy cow 10T?  Thats a big chunk of iron.  Kinda surprised you had
> enough cable length for that... :)

I just finished winding 10T through the largest #31 clamp-on sold through DX 
Engineering.  Tight and even turns will get you there.   It's located right 
at the K3's RS-232 port.   However, there's still not enough choking 
reactance to bring the noise floor down all the way.  So, there may be a 
direct path of RFI through the connector.

Admittedly, I am being fussy here because an antenna connected to the K3 
masks the problem.  But, I'm still bothered with the problem since the K3 
should be immune to a device connected through its RS-232 port.  From here, 
I see two possible solutions:

1) Adding an RS-232 card to my PC thereby eliminating the USB converter; or
2) Using an opto-isolated RS232-to-USB converter.  I found a couple on the 
web, but these are big $$$ devices.

Either way, there's no guarantee that either choice will completely mitigate 
the noise.  My K3 is current with grounding mods and it also has the new 
remote KIO3 board.  I'll keep experimenting....

Paul, W9AC