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Brief msgs via 9600 Pacsats?



Thanks RIchard, now  may I rely some more on your's and others' PACSAT
operating experience...

I got the PACSAT Protocol spec last night and read it cover to cover, but
still have no send/receive operating experience.  I am looking at how to
easily send and receive very brief (APRS like) messages via the PACSAT if
I am out on the open road or sea and have no other means of communication
other than this new Kenwood HT, my laptop and handheld antenna.

Here are the issues which I need to figure out.

   1) It appears that a message may be uplinked as a "file transfer"
      which is done via a "connection" to the PACSAT or it may be
      sent in a few UI frames with handshaking.

   2) If I have to take a second or more to turn the Kenwood transceiver
      TNC from the UHF band for receive to the VHF band for transmit
      and then back, it would appear that it would miss ANY pacsat
      handshaking packet unless there were a known and long delay
      between the uplinked request and the downlinked response.

Is this handshaking delay a documented quantity?  If the return handshake
is missed, I assume it is not repeated.  Thus there is no chance that this
would ever work.  It all boils down to the limits on the T/R turn around
expectations of the PACSAT protocol as implemented.

3)  This being the case, does anyone see a way to overcome this
limitation and still be able to uplink your short (typically one
line) message from the wilderness with such a long delay between transmit
and receive?

In any case, I can see that I can RECEIVE a brief message in Receive
only mode if the essence of the message is included in the Directory
broadcast and limited to about 30 characters in the Subject line and a few
other words in the Key Word display..

Actually, from what I read, these fields can be larger, but the limits
above are what I observe on my WISP (receive only) Directory display.

de WB4APR, bob


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