[PCR-1000] packet output

Thu, 30 Jan 2003 17:10:49 -0700

Speech sounds very err clipped? Bad enough that I get off my butt and 
switch back when scanning.

John

Brian Winter wrote:

>Hi Patrik,
>I have seen this mod before and have always thought it a little dangerous
>for questionable gain.  However, this discussion has left me with no moral
>choice :) !!
>
>I performed the mod (its not too tricky after all) and results are
>interesting.  I havn't taken any "scientific" comparative measurements yet,
>but it is obvious that the discriminator output is considerably better than
>the speaker output, allowing WxSat to lock and decode at much lower signal
>levels (ie worse noise).
>
>I still don't really understand why the difference should be so great and I
>would be grateful for any explanation.  I'm beginning to think that its not
>so much about high frequency cutoff (which is obvious by listening to the
>two outputs via computer), but more about phase delay and possibly _low_
>frequency response - investigation tells me the NOAA siganls are not simply
>FM modulated with 2400 baud data: the modulating siganl is itself AM
>modulated with the telemetry data - and I reckon thats where the low freq
>components are.  Anyone care to add to the theory or point me to a useful
>website (putmeoutofmymisery.com ?).
>
>Interestingly, I have tried the discriminator output with ACARS and results
>seem to be worse than speaker o/p at first trial - less messages decoded,
>although a fairly short test.
>
>Further, can anyone with a pcr1000 tell me what speech sounds like from
>their packet output - I need a sanity check on my mod.
>
>Thanks again Patrik for getting me into this - I think there will  be much
>to be gained in some areas.  If this mod represents the packet output on a
>pcr1000 then I would strongly recommend that enthusiasts should use the
>packet output for NOAA for a lower threshold.
>
>Brian
>
>
>
>----- Original Message -----
>From: "Patrik Norqvist" <[email protected]>
>To: <[email protected]>
>Sent: Wednesday, January 29, 2003 10:09 PM
>Subject: Re: [PCR-1000] packet output
>
>
>  
>
>>At 21:30 2003-01-29 +0000, Brian Winter wrote:
>>
>>    
>>
>>>I have a PCR100 (ie with no packet output) currently dedicated to
>>>      
>>>
>satellite
>  
>
>>>stuff - time to experiment with that and possibly reconsider equipment
>>>      
>>>
>usage
>  
>
>>>I suppose.  I am particularly impressed at the report of horizon to
>>>      
>>>
>horizon
>  
>
>>>coverage.  Now that really would be worth having.
>>>      
>>>
>>This link may interest you:
>>
>>http://www.webdeals.net/100mod.htm
>>
>>Regards
>>    /Patrik
>>
>>    
>>
>
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-- 
John Lang, 
E-mail: [email protected] 

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