[Elecraft] K3 AFSK RTTY overdrive - no ALC

[Jim Brown]

On Sun, 23 Nov 2008 19:54:24 -0500, Joe Subich, W4TV wrote:

>It us likely that 
>the ticking is the computer polling the radio.  You will find 
that 
>is due to ground loop ("pin 1") problems. 

Ah! That's a source I hadn't thought of, but it's a perfect 
example of a "pin 1 problem" -- you inject noise at a shield 
contact associated with one circuit and it shows up somewhere 
entirely unexpected! I've never heard it, since my serial cable is 
wired with signal returns to the shells on both ends. :) 

Yes, I agree with all of your advice -- use the line input, run 
the sound card about 6 dB below it's max output, adjust the line 
in gain accordingly. 

Thanks!

Chad -- I still don't understand why you want to use the mic input 
for data. I like to leave my mic plugged into the front panel and 
the sound card plugged into the rear panel. The only change for 
data modes is that I'm feeding Line Out back into the sound card 
so that MMTTY can decode it. 

An important difference between the MP and the K3 is that the K3 
has a 20 dB pad in front of the Line In transformer. As Joe 
observes, an additional 20 dB pad outside the radio is too much. 

When I'm doing SO2R on SSB, I plug my mic (an EV RE11) into the 
computer and let N1MM keep track of where it should go. It works 
quite well here. 

73,

Jim K9YC