[aprssig] Sony/RatShack 20-1601 GPS Rx

Mark Earle wa2mct at mearle.com
Sun Aug 21 21:20:33 EDT 2005

At 06:08 PM 8/21/2005 -0700, you wrote:
 >I have this GPS functioning, and I see it's Data
 >showing on the bottom of my MacAPRS v3.4.5 Map window;
 >When I set my MFJ 1270C to NMEA Beacon 1 (or whatever)
 >my tnc will NOT key the PTT line!
 >What's going on here?
 >I have it all rigged up just fine to run APRS/Packet
 >without the
 >GPS running, but when I set the rx to beacon the Data,
 >the tnc won't key....HElllllLLLLLLLP!
I presume from the above, the GPS is on one port, and the TNC on another, 
on your MAC.

If this is how you are operating, the MacAPRS software determines when the 
TNC will transmit. You should not set the tnc to beacon 1.

Those commands assume no mac - that the GPS would be connected directly to 
the TNC. (with a cable of opposite wiring from connecting it to a PC). In 
that mode (GPS <--> TNC <--> Radio) you would have a basic tracker, capable 
of transmitting your position ever "beacon interval". No computer needed 
for that.

While this works, most folks wanting a tracker use a Tiny Trak or something 
similar. A small board (GPS <--> TT <--> Radio). The advantages are:
         Lower cost - TT is about $30
         Smaller size - TT is a small circuit board 2 x 2"
         Lower current consumption than a TNC
         "Smart" software. Instead of beaconing every n seconds, it will 
vary the rate, depending if you're moving, stopped, moving faster, make a 
turn, etc. This is called "Smart Beaconing", "Corner Pegging", or other 
names, but it's much nicer than every minute, and all automatic.

 >Start your day with Yahoo! - make it your home page
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 >aprssig at lists.tapr.org

       ) )    de WA2MCT Mark
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