[Elecraft] RE: Obscure RTTY bug?

[K2MK]

Hi Iain:

I was curious to see where this thread was going. I too noticed crackling 
monitor audio on AFSK A mode. But in my case it was present when the dual 
passband filter was engaged and disappeared when I was listening with the 
normal filter. I'm not bothered by the crackling I just hope it is not going 
out in the transmitted signal.

73,
Mike K2MK



[Elecraft] Obscure RTTY bug?
Iain MacDonnell - N6ML
Wed, 31 Dec 2008 14:40:25 -0800


Preparing for the ARRL RTTY Round-Up this weekend, I ran into a strange
problem. Using "AFSK A" mode, feeding transmit audio into the K3's line
in from the computer running MMTTY (also tried with DM780, with the same
result), I would get a crackling noise along with the RTTY tones in the
K3's monitor audio. I don't know if the crackling is transmitted, or
just in the monitor. Levels are set for 5 bars on the ALC meter, and
the problem occurs in "TX TEXT" mode.

After lots of tearing my hair out (well, at least tearing my cables out
and trying other ones), I observed two things that make it go away:

1) Changing to USB ("REV DATA")

2) Turning *off* "TEXT DEC"

I recorded the probleml, from line-out, with text decode on and off:

http://www.dseven.org/k3/


Why the text decode would cause crackle in the monitor audio, and why
not in "REV" mode, I'm not sure... but I would like to be able to have
the decoder turned on...

    ~Iain / N6ML