Simply un select the internal mic in the mixer used for sound card settings.
73
Jim W7RY
----- Original Message -----
From: <Gedking@aol.com>
To: <k0rc@citlink.net>; <rtty@contesting.com>
Sent: Thursday, February 05, 2009 5:46 AM
Subject: Re: [RTTY] Affordable PCI sound card recommendations?
>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@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@dseven.org>
> To: "Robert Chudek - K0RC" <k0rc@citlink.net>
> Cc: <RTTY@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@dseven.org>
>>> To: <RTTY@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
>>>>
>>>>
>>>> _______________________________________________
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>>>> RTTY@contesting.com
>>>> http://lists.contesting.com/mailman/listinfo/rtty
>>>>
>>>
>>
>
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