Peter L. Jackson wrote:
> Hello Joe and fellow group members,
> I have been following this debate about sound cards with interest as its
> a popular theme at the moment that crops up on various forums.
> In your email to the group Joe ...
> />>>>The noise that the WSJT decoders must cope with is a combination of
> cosmic noise, atmospheric noise, and receiver noise; sound card noise is
> many tens of dB's weaker, and entirely negligible.<<<<</
> I take it that the referral to sound card noise is reference to the
> particular chip set used along with associated components making up the
> particular sound card.
> If the card is placed external as in the case of a USB sound card, wont the
> chance of internal injected hum, inter mods etc. be greatly reduced
> than if residing internally in the PC.
> Wouldn't S/R also be improved whether one is using WSJT or monitoring on a
> waterfall looking at weak signal's in general ?
There is no reason for any well made sound card to introduce hum or
distortion just because it is located inside a PC. Hum is almost always
indicative of a ground-loop problem, and can usually be resolved with an
audio isolation transformer between radio and computer. In addition,
WSJT is relatively immune to hum because 50/60 Hz and the first
half-dozen harmonics are well below the WSJT frequency range.
> Also can low latency ASIO audio drivers that allow high speed cw and
> fast TR transition be also be of benefit ?
> This seems to be the holy grail that the sdr-1000 flex radio forum
> members are seeking to achieve.
No significant benefits to WSJT, which does not need extremely low latency.
-- 73, Joe, K1JT