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[aprssig] ISS donwlink of SSTV! (and APRS beacons)

Robert Bruninga bruninga at usna.edu
Fri Oct 10 00:44:40 UTC 2008


> ISS SSTV Operations Planned for October 12
> from 18:00-21:00 UTC.  This is your opportunity...

Due to hightened interest to the general Ham radio community for
this mission, I again suggest that all Shuttle Audio
Retransmission Faclities consider adding an old TNC and
144.39MHz APRS beacon to their system.  This TNC will alert all
surrounding mobiles (with APRS display radios D7, D700, D710,
VX8R, HAMHUD's, etc) that the retransmission is on the air and
what frequency to tune.

Just load the correct beacon text, set the rate to 1 minute and
connect the TNC's XCD (external carrier detect) to the re-trans
PTT line, then whenever the re-trans is on the air, then a 1
minute announcement beacon will show up on  all surrounding
radios.

You may have to invert the sense of the XCD line.  Here is a web
page on this APRS local alert system:
www.aprs.org/On-Air-beacons.html

I appologize for repeating myself, but no sense in adding this
system after the Shuttle is back on the ground!  Now's the time!

Here Is how it can look on the front panel of an APRS radio to
mobiles in the area:

+------------+
| 147.45NAN  |
| SAREX ReTX |
| SSTV ops   |
| Goddard    |
+------------+

Where 147.45NAN is the retrans freq for the WA3NAN radio club at
NASA Goddard, for example.

A nice reminder that HAM Radio is again active in SPACE!

Who will put out these beacons unless YOU hook it up for your
local audio-retrans guy?

Bob, Wb4APR





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