[TenTec] Digital (PSK31) Communications

[Bob McGraw - K4TAX]

First let me say, "if it isn't a microphone it should not be connected to 
the microphone input".  Of course it can be done but one has to be very 
careful with the method they get the soundcard level {usually between 0 dBv 
and -10 dBv} down to microphone level {usually -40 dBv} and still maintain 
the S/N ratio.  A fixed resistive pad or attenuator with a loss of 30 dB is 
the better way to go.

Now using the Line input, the control that handles the level to the line 
input or accessory jack level it the correct one to use.  At the same time, 
it is possible to overdrive the input stage, with a the level control after 
the input stage, then no amount of "turning down" the level will correct the 
overdrive condition.  The source {i.e. soundcard} level must be reduced.

Remember the PSK-31 signal is an analog signal designed to pass through the 
analog audio path of the transmitter regardless of which input, MIC or 
AUX/Line, that you choose.  It is the fact that the required level of the 
MIC input is some 30 to 40 dB less than that of the AUX/Line input.

73
Bob ,K4TAX




----- Original Message ----- 
From: <Mykeyw9 at aol.com>
To: <tentec at contesting.com>
Sent: Saturday, February 02, 2008 12:38 PM
Subject: Re: [TenTec] Digital (PSK31) Communications


>
>
> In a message dated 2/2/2008 9:39:27 A.M. US Mountain Standard Time,
> RMcGraw at Blomand.net writes:
>
> A  comment to the point of setting vs. controlling the power on the 
> Jupiter.
>
> For modes like PSK-31 the Jupiter should be configured to  operate at its
> rated output power or 100 watts.  <SNIP>
>
> This is  basic NO NO.  Reduction of the Jupiter lower to 25  or 35 watts
> en have the sound card audio drive the Jupiter to 25 to 35  watts <SNIP>
>
> Bob
>
> Do these comments apply for both Mic  input or accessory jack
>
>
>
>
> Mike  W9UQB/7 DM33XP
>
>
>
>
> **************Biggest Grammy Award surprises of all time on AOL Music.
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