I have a Amateur Radio License.
I am specifically experimenting with 2m digtal data, running at 9600bps and 1200bps rates, which I have to admit is quite slow.
I found the AX25 stuff related to amateur radio to be far too complex for my purposes, so I created a simple HDLC layer of my own and used the soundmodem driver to modulate my signal.
At the lowest level I simply created a byte stream between my two ends. However, on the real air I followed the AX.25 packet formatting so people could puruse what I was doing on the air if they wished.
(I have an RF chamber of my own for testing without bothering people)
The idea here was to see what sort of propogation characteristics I got from an antenna setup at my house, and a small setup in my vehicle.
At each end I have a small PC setup and basically they ping each other over the air as I drive around
This is the second test I performed:
I did further tests of greater distance. My house based antennas is only 30 feet off the ground. And I could basically get acceptable coverage for about 1 mile when I did not go past the freeways.
I also am a Packet Sig coordinator on a local amateur digital repeater and have access to a few others which I experimented with further.
Elevations of those sites, were about 500ft, 2800ft, and 2800ft.
Testing with the higher sites (2800ft) I was able to manage communication over about 10 to 15 miles.