Hi Curt.
The biggest difference is in the location rather than design of the card.
That inside a desktop or laptop PC tends to pick up significantly more noise fron the other circuitry than an external
USB card.
Ensure that you turn off the Windows burps and farts and other sound effects or they will be transmitted along with your
wanted signal.
This from the Ham Radio Deluxe Interfaces Manual by Simon Brown and Peter
Halpin.
( http://www.ham-radio-deluxe.com/Portals/1/Documentation/Interfaces.pdf )
"And one last tip: the onboard soundcards supplied with many computers are very basic indeed. Many people report seeing
"ghost" signals on their waterfalls: these are very often caused by below-par soundcards. If you can install a good one
- I use a Creative Audigy 2 - you will be pleasantly surprised at how 'clean' the waterfall looks. An added bonus is
that you will be able to decode weaker signals too! Adding a second soundcard to any system can be recommended: but
please make sure it's a good one."
On 17-Sep-10 13:51, Curt Nixon wrote:
Hi Nigel:
I know that is technically and intuitively correct but I never saw a lick of
difference in ANY digi mode I have run
between the old SB and the new 24bit/192Khz cards I have. I have tried several
different audio interfaces ( I do
commercial digital recording of everything from full symphony to small groups).
Only when I use the card for the SDR set
up do I see any actual operation difference.
In PSK, any station I could see as a trace would decode.
Not disagreeing at all with the argument for low noise cards but my practical
experience with the SB cards has been very
good.
I suspect that, especially with the Phase modulated modes like PSK, there are
some issues with phase coherence and phase
linearity thru the system that could affect decoding. Maybe I got lucky with my
two old cards.
Curt
KU8L
Nigel Gunn G8IFF/W8IFF wrote:
Although you'll copy far more station if it is high quality/low noise, at least
on the Rx side.
On 17-Sep-10 13:19, Curt Nixon wrote:
I doesn't take a high capability sound card either.
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Nigel A. Gunn, 1865 El Camino Drive, Xenia, OH 45385-1115, USA. tel +1 937
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Amateur Radio G8IFF W8IFF (was KC8NHF 9H3GN), e-mail ni...@ngunn.net www
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