[ao16aprs] RE: [sarex] AO16/LU19/IO26 Renewed TRAKNET Interest

["Tim Cunningham" <tim_cunningham@mindspring.com>]

The PSK modem performs the Doppler tuning by using the UP/DWN
signals through the microphone connector on most conventional SSB
radios that have this feature.  However, the radio must be initially
pretuned
to get a lock on the PSK downlink and then the PSK modem takes
control of the Doppler tuning process using the UP/DWN mic connector
signals.  The problem is if the signal is lost for a period of time the
receiver must again be manually tuned to get it back on track.

There may be some other sophisticated PSK modem implementations
that I am not aware that perform a better job of stay on when the signal
drops out momentarily   I am using a PACCOMM PSK-1 TNC that plugs
into a modem disconnect header of a standard TNC-2 compatible.

The signals on AO-16 are weak in comparison to UO-22 or KO-25.
Since most satellites are between 0 and 35 degrees most of the time
on the average, it is possible that some of the omni-directional antennas
may be able to decode the data when the bird is in range.  If it passes
over your location at higher angles, then another distance stations could
capture the signal and broadcast it over their local network.

I plan to put my $0 (parts from the junk box) modified TNC back on the
air this weekend in my jeep to see how it works.


73's

Tim - N8DEU
Huntsville, Alabama




-----Original Message-----
From: Bob Bruninga <bruninga@nadn.navy.mil>
To: TAPR AO-16 APRS Special Interest Group <ao16aprs@lists.tapr.org>
Date: Wednesday, August 25, 1999 7:00 PM
Subject: [ao16aprs] RE: [sarex] AO16/LU19/IO26 Renewed TRAKNET Interest


>On Wed, 25 Aug 1999, pete wrote:
>
>> Whats the baud rate of the downlink?
>
>1200 baud PSK.  Needs UHF SSB receiver and PSK modem.. and doppler
>tracking...
>
>
>
>
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