Order Tray | Contact Us | Home | SIG Lists

[aprssig] APRS and RF data modules

Robert Bruninga bruninga at usna.edu
Thu Apr 28 14:33:34 UTC 2005


On Apr 28, 2005, at 4:02 AM, Andrew Rich wrote:
> Has anyone dabbled with APRS and these little 
> 433 MHz data modules ?

Here is what I want:  Once someone develops a small
1W transmitter for APRS, here is how I will use it:

To track my stolen bike, canoe, and lawnmower!
(and anything else worth tracking)...

I want a tiny transmitter that runs on 4 to 8 AA cells 
(no GPS)and will operate for 2 days with a 10 second 
on, 20 second off rate on the national DFing channel.

Using nothing but my mobile rig I can find it in under
an hour I am sure, once I get close enough to hear
it.  If you dont believe this, see my omni-signal
strength DFing technique:

http://www.ew.usna.edu/~bruninga/aprs/dfing.html

Look carefully at the fade-circle technique and remember
once you understand it, you dont need APRS, or anything
but a radio to find any transmitter....  just drive till
the signal is strongest and you got it!

I lectured my radio club on this manual technique using
nothing but their mobiles and before the meeting I had
hidden my HT with a rubber band around it on low
power within 3 miles of the clubhouse.  After the meeting
everyone was encouraged to go find it.  The first team
found it in about 15 minutes using only their mobile rig
and an HT (for the last 100 feet).

This technique works, ANYONE can do it, and all you 
need to do is *think and visualize signal strength*
and start driving.    Good luck!

8 AA cells could power a 1W XMTR for 48 hours
easily on the above 10 sec on, 20 sec off cycle
and with a CWID during the on time...

Id make the XMTR and cells into a tube that just
looks like part of the bike structure so that it
wont be obvious...

Bob, WB4APR





More information about the aprssig mailing list