Okay, all good suggestions. Thanks Jim and Joe.
I didn't stop at just removing the RS-232 cable. I removed EVERY cable to
the K3 other than the single cable for audio in. (I kept the grounding
braid and antenna, but still tested using the TX TEST mode, no RF.)
Tried the FP mic connector. Same behavior.
Shorted out the series resistor on the 20dB attenuator and connected to the
LINE IN on the K3. Cranked up the soundcard output, turned the LINE IN gain
to around 5.
Same problem. Monitor audio sounds fine at 2 bars ALC with no hint of
ticking. Increase either the soundcard output or K3 input gain to get 3
bars ALC and ticking begins. Goes from no ticking to ticking with only one
"click" of the K3 mic/line in gain.
No setting of soundcard output and K3 input gain results in 3 bars more more
of ALC without the ticking sound. No hint of ticking at 2 bars ALC.
Soundcard is an ol' favorite, a Creative Labs PCI 128 CT4750...been working
great for years and scores the 7F on Writelog. Works fine at any output
level with any other radio. Continues to work FB with FT-1000D.
On Sun, Nov 23, 2008 at 7:13 PM, Jim Brown <[EMAIL PROTECTED]>wrote:
> 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
>
>
>
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