[RTTY] Affordable PCI sound card recommendations?

[Gedking at aol.com]

I sometimes use my little dell laptop on another rig and it picks up  outside 
noises and even picked up the sound from my other rig and decoded it. I  been 
looking for the built in Mic but can't find it. No big thing but it bugs  me
ED K8OT
 
 
In a message dated 2/5/2009 12:58:33 A.M. Eastern Standard Time,  
k0rc at citlink.net writes:

There's  other things to consider beyond the soundcard. The soundcard is 
usually on  the bottom of my suspect list.

In MMTTY you can select from three  different demodulators by clicking the 
TYPE button. Above and slightly to  the left of this button will be the 
acronyms FIR, IIR, and PLL as you  click through them. Depending upon band 
conditions at the moment, one of  the three can provide better copy.

Something beyond operator control is  band and path conditions. It's possible 
to have a S-9 signal and not be  able to decode because of bit distortion 
(delay). This is especially  prevalent on signals going over a polar path.

Another issue can be AC  hum (ground loop). A few months back I experienced 
this for the first time  in my shack. I saw the ripple on the scope. It just 
didn't "look right"  and MMTTY wasn't decoding for beans. I figured out the 
problem but I don't  recall what I did at the moment.

The difference between copy and no  copy is rig dependant too. I was not a 
believer until I bought an Icom 756  Pro III and turned on the RTTY twin peak 
filter. It brought signals out of  the noise the I would never been able to 
copy on my TS-950SDX... even with  all of it's filters and DSP.

Another source of "self inflicted QRM" can  be your own monitoring system. If 
you are picking your RX audio from the  external speaker, it (the 
loudspeaker) will pickup room noises (another  RTTY signal from a different 
radio perhaps?) and feed that into your  soundcard input. Now you have two 
competing signals going into the MMTTY  decoder.

Just a few thoughts.

73 de Bob - KØRC in  MN


----- Original Message ----- 
From: "Iain MacDonnell - N6ML"  <ar at dseven.org>
To: "Robert Chudek - K0RC"  <k0rc at citlink.net>
Cc: <RTTY at contesting.com>
Sent:  Wednesday, February 04, 2009 10:36 PM
Subject: Re: [RTTY] Affordable PCI  sound card recommendations?


>
> Hi Bob,
>
>  The problem was that weaker signals were not decoding (cleanly). It's
>  difficult to quantify, but judging by ear, the signals should have  been
> strong enough to fully copy. Changing from the on-board - most  likely
> AC97-based (I'm not at the site now) - interface to a couple  of
> different USB devices (an EMU-0202 and a Griffin iMic2) cleared  the
> problem right up - those weaker signals started decoding just  fine.
>
> I think I'm going to go for something in the sound  blaster line. I'd
> like to have something that does most of the work in  hardware, rather
> than a software codec - it just seems like that might  be more reliable.
>
> Thanks for the input... and for Qs in a  bunch of recent contests :)
>
>     ~Iain /  N6ML
>
>
>
> Robert Chudek - K0RC wrote:
>>  "We've tried the on-board audio with MMTTY, and had major problems  
>> decoding."
>>
>> What were the major problems  you experienced decoding?
>>
>> To answer you question,  virtually any soundcard will provide good 
>> results. The SB Live!  series work well.
>>
>> 73 de Bob - KØRC in  MN
>>
>>
>> ----- Original Message ----- From:  "Iain MacDonnell - N6ML" 
>> <ar at dseven.org>
>> To:  <RTTY at contesting.com>
>> Sent: Wednesday, February 04, 2009  9:38 PM
>> Subject: [RTTY] Affordable PCI sound card  recommendations?
>>
>>
>>>
>>> I  need to outfit a number of WinXP PCs at a contest station for
>>>  RTTY. We've tried the on-board audio with MMTTY, and had major
>>>  problems decoding. I got around this for the last contest (RU)
>>>  by using external USB audio interfaces, but want to install
>>>  something internal in each PC to make it permanent. I've seen
>>>  a number of Sound Blaster Live! options on eBay in the order
>>>  of $10-15 shipped, but thought I'd ask here if there are any
>>>  particular models that work well, or are known to not work  well
>>> for RTTY decoding (and maybe AFSK transmit  too).
>>>
>>> TIA for any  recommendations...
>>>
>>>     ~Iain /  N6ML
>>>
>>>
>>>  _______________________________________________
>>> RTTY mailing  list
>>> RTTY at contesting.com
>>>  http://lists.contesting.com/mailman/listinfo/rtty
>>>
>>
>  

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