[Elecraft] Possible phase noise question...

[Joe Subich, W4TV]

While I hate to point fingers in this situation, the symptoms are
that of an unstable (noisy) sound card.  Given the documentation
of insufficient filtering, regulation and bypassing in that
particular device, a noisy USB power line (remember the computer
power supplies are switchers with the potential for broadband
hash) would directly modulate the codec (DAC), and the op-amp
audio stages feeding the transmitter.

73,

    ... Joe, W4TV


On 2014-07-01 10:11 AM, David Cole wrote:
> Hi,
>
> We are starting to focus on the Signalink soundcard itself...  I can't
> imagine it is the Elecraft K3 failing, as a dead carrier does not cause
> the spray, only when audio is being supplied to the transmitter, and
> only when from the Signalink, does the problem happen...
>