[RTTY] Sound Cards and Software

[Robert Chudek - K0RC]

GM Jim,

I wasn't aware of the survey you posted so thanks for that link!

I did a quick search and could not find a reference to the discussion / 
article I am thinking about. It might have been in conjunction with sound 
card testing for SDR purposes although I do recall specific mention about 
RTTY decoding showing minimal improvement across the whole spectrum of audio 
cards being tested. What I recall is this was one person who tested a 
handful of cards in a more-or-less lab environment using test equipment.

I'll continue to search and hopefully I can find the source of my 
recollection. Or maybe someone else recalls the comparison I'm thinking 
about and will comment or post a link.

73 de Bob - KØRC in MN


----- Original Message ----- 
From: "Jim N7US" <n7us at arrl.net>
To: <rtty at contesting.com>
Sent: Thursday, September 17, 2009 5:03 AM
Subject: Re: [RTTY] Sound Cards and Software


The soundcard survey was way back in 2001:

http://www.qsl.net/wa9als/sound_results.htm

Jim N7US




-----Original Message-----

Bill,

A few years ago "someone" (sorry I don't recall who it was) ran tests on a
variety of soundcards, from cheap $20 cards to high-end $200+ cards. The
result was for RTTY use, there wasn't a significant difference in
performance among all the cards tested. That is not to say the expensive
cards couldn't do more, it was simply that our RTTY decoding needs did not
take advantage of the high-end features. The conclusion was to save your
money and put it toward a second decoder and run it in parallel.

Other fellows have run comparisons between MMTTY and other decoders, and
specifically high-end standalone units like the HAL products. MMTTY always
compares favorably to other decoders. The performance difference is always
small, but the edge will sometimes go to the external unit. Overall, the
MMTTY decoder continues to be near the top of the list of "state of the art"

decoders, even though it was developed a decade ago.

Another software decoder that is a strong performer is RITTY by K6STI. Many
contesters continue to use this soundcard based software even though it is a

DOS based decoder. I don't think you can buy it anymore. It was taken off
the market after copyright violations were discovered by its author. This
was a terrible loss of creative talent for the Amateur Radio community
perpetrated by some individuals who thought pirating software was an
acceptable activity.

Regarding "noise" around your ellipsis on the MMTTY display, this is normal
bandnoise. If you select the FIR decoder the software will provide a crisp +

(plus) symbol when a station is tuned in properly. This display will also
have random noise although to a lesser degree.

73 de Bob - KØRC in MN


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