[Date Prev][Date Next][Thread Prev][Thread Next] - [Date Index][Thread Index][Author Index]

Re: Innexpensive Pacsat Modems?



On Tue, 24 Feb 1998 JOppen6115@aol.com wrote:

> I have been researching the AMSAT archives and saw you were involved in a
> discussion about a $3 pacsat modem in early '97.  I could not find the details

All it takes is an 89 cent XOR gate to XOR the TXD and 1200 baud clock
from any AX.25 TNC and inject the result into your 2m FM mic jack.  This
way, anyone can TRANSMIT to the 1200 baud pacsat birds with only about 10
watts or less from any 2m mobile.

Neat thing is, that for APRS tracking of GPS mobiles all over the country
we only need ONE PACSAT receiving station.  That station injects the
packets he hears into the WORLDWIDE Internet APRS channel
www.aprs.net:10151 and then any of the hundreds of APRS-internet IGATES
then in turn make those packets available to VHF networks across the
country.

Now all of the APRS versions are INTERNET TCPIP capable.  This means that
anyone within a hundred miles or so of any APRS IGATE can communicate
keyboard to keyboard with anyone else so situated worldwide.

IGATES:  Steve Dimse, K4HG, and the other APRS authors have implemented
RF-INTERNET-RF messaging in his Internet APRServe sites and all APRS
software.  There is a validation process to assure only licensed FCC
stations can interject messages for linking back out to RF.  But this
system does permit mobiles almost anywhere in the country within range of
an IGATE to do keyboard messaging to any other station either logged onto
APRServe or within radio range of a local IGATE.

NOW ALL WE NEED IS A PACSAT GROUND STATION TO JOIN THE SYSTEM.  Then we
can track and receive messages from mobiles anywhere in the world via the
system.  And the APRS GPS mobiles only need a 2m FM moble rig and the 89
cent mod to transmit.

For more info go to Steve's site WWW.APRS.NET and visit his APRS VIrtual
Meeting page.

de WB4APR





AMSAT Top AMSAT Home