[Elecraft] K3 in NAQP SSB

[Jim Brown]

On Mon, 18 Aug 2008 11:27:17 -0500, Bob Evans wrote:

>Unfortunately, I was not able to go full SO2R with my new microHAM MK2R SO2R
>box and N1MM DVK because of RF feedback getting into the audio lines.  I had
>the same problem with my DXdoubler, so I know it is not the microHAM box,

Don't be so sure of that. MOST ham rigs and ham accessory boxes are built 
with pin 1 problems, which are the primary cause of RFI. While I have not 
TESTED any of the accessory boxes, I have studied the construction of several 
of them, and they sure look like they're built with classic pin 1 problems. 
For this reason, I don't use these boxes. Instead, I use the simple 
interfaces shown in 

http://audiosystemsgroup.com/HamInterfacing.pdf

To gain a better understandinhg of RFI and "the pin 1 problem," see 

http://audiosystemsgroup.com/RFI-Ham.pdf

My K3 drives a Ten Tec Titan 425 to the legal limit into coax-fed dipoles 
that are roughly 100 ft directly overhead, and to a 160M vertical roughly 25 
ft from the operating bench. Every antenna has a good common mode choke at 
the feedpoint. I have never seen an RFI problem with my K3. I DID have RFI 
problems with my FT1000MPs in the same setup, which I had to kill with common 
mode chokes on the mic cables. 

For NAQP SSB, I used my T22 Thinkpad in N1MM's #2 audio setup as shown on 
pages 58 of the Ham Interfacing pdf to drive two MPs left and right. (My K3 
is in Aptos for repair, but the setup worked fine with one MP and the K3 
before the XMIT died). NAQP, of course, is a 100W contest, so the amp was 
off. 

73,

Jim Brown K9YC