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RE: Anybody can Help me????



Perhaps I can clarify a bit:  The Symek 38k4 output doesn't work well, if at all, for 9600 baud packet (as Bob described).

The TS-790A needs a different output for 9600 baud packet--from the sub-band discriminator for full duplex operations. I have the two lines coming out of the TS-790A on different connectors/pins.  This mod may or may not have been changed during the 38k4 modification on his rig.

Perhaps the following writeup from the AMSAT TAPR DSP-93 project will be helpful to Enzo, should he need to run another line out of the rig:

If you need to see the mod for 9600 baud packet on the TS-790A (other vintage satellite rigs) see page 14 of this document:

ftp://ftp.tapr.org/dsp/Texas_Instruments/dsp93/manuals/DSP93_Ops_Manual.pdf
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Subject: [amsat-bb] RE: Anybody can Help me???? 
From: "Robert McGwier" <rwmcgwier@xxxxxxxxxxx> 
Date: Wed, 21 Jul 2004 15:30:03 -0000 
In-Reply-To: <40FE809A.7010701@swbell.net> 

--------------------------------------------------------------------------------

Roy:

Hopefully this is what has been done. If it is deeper surgery, which it
sounded like it might be from his concerns about knifing the rig further,
then some further details might be in order for us to help him.

Bob


-----Original Message-----
From: Roy [mailto:rdwelch@swbell.net]
Sent: Wednesday, July 21, 2004 2:42 PM
To: rwmcgwier@comcast.net; AMSAT BBS
Subject: RE: Anybody can Help me????


Bob, if he is using the IFD board, he will not have widened the bandpass of
the radio
when used on normal 9k6 or FM voice operation.  The IFD board in just
inserted in the
1st IF circuit to "sniff off" a bit of the output of the first IF stage
while still
passing the same signal through a unity gain amplifier, on the IFD board, on
to the
normal xtal filter following the first IF stage.  The radio then can operate
normally
as though it had never been modified.  The "sniffed off" signal is passed
through a
completely different wide band IF on the IFD board, detected, producing the
38k4
output audio to the 38k4 TNC.

--
73, Roy -- W0SL

--------------

73,

Mark Hammond N8MH (formerly KC4EBR)
----
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