[RTTY] sound card

[David G3YYD]

Peter

First do not buy a very cheap one. You get what you pay for. The performance
will be substandard. I tried a £5 one to see what it was like and I could
see spurious generated by the sound card about 30 to 40dB down from the
wanted signal. The transmit side was similar.

However do not buy an expensive one either that would be a waste of money. I
have a very good one (Asus XONAR D1) which I use for SDR. That is worth it
for SDR. It samples at 192KHz. That is not needed for data audio 48KHz
sample rate is all that is needed.

I suggest you look at cards around the £25 mark. At around this price point
cards I have used perform very well for receive and transmit.

The on board motherboard audio I have had variable results my previous PC
was very good. The one on the current PC should be good but isn’t. Probably
due to motherboard design rather than the chip used.

One word of caution, modern sound cards use the DVD sample rate
standard(48KHz) and not the old CD standard (44KHz). Beware software that
uses a default sound card setting of 11025 sample/sec (e.g. MMTTY), it will
actually be 11100 (nearest multiple of 300) and your tone frequency will be
incorrect. Avoid this problem by ensuring the software is set for 12000.

73 David G3YYD



-----Original Message-----
From: RTTY [mailto:rtty-bounces at contesting.com] On Behalf Of
peter.jackson17 at ntlworld.com
Sent: 11 June 2014 18:40
To: rtty at contesting.com
Subject: [RTTY] sound card

I am going have a new computer built and I would like to know what  the best
criteria for the sound card is please naturally with data modes in mind.
73 Pete G3KNU
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