[TriLUG] Linux and HAM radio questions

[Joseph Mack NA3T]

On Tue, 28 Mar 2006, William Sutton wrote:

> For you amateur radio operators, I have some questions
> 1. What is the data capability of packet radio

I haven't done any of this for about 10yrs, but here's the 
general idea

bandwidth (==data rate) is determined by regulations. The 
higher the freq, the more bandwidth you're allowed. At 2m 
you can get 1200 baud (some band you can do 9600, not sure 
where).

expect for a small minority, hams aren't experimenters 
anymore and so hams use commodity (ham) radios to transmit 
data. These radios are for voice only and usually have a 
bandwidth of 3kHz. You can't get much data rate out of this.

Some experimenters have built decoders to operate at the 
28MHz and plugged these into the back of hacked radios. They 
get more data rate. At 10GHz you get get about 10Mbps, but 
you have roll your own and you have to understand microwave
RF.

The ARRL, which loudly proclaims its wish for ham radio not 
to be a technical hobby, only interest in increasing the 
technical level of packet radio, has been to exhort 
commodity ham radio manufacturers to make their radios 
packet-able.

At the time when 1200bd was the rage on 2m I was getting 
14,4k over a phone line to my local DOS BBS. I decided that 
ham radio was not the place to put effort into data 
transmission.

> 2. What facilities are there in Linux for 
> transmitting/receiving audio streams over radio?

the protocols are in the kernel. Just turn them on an 
rebuild. You have some console program that allows you to 
type and you then send the ham radio ready packets over a 
serial line to and from your packet-able radio, the replies 
coming back on the screen. (I haven't done this with Linux - 
but it must be similar to the way you did it in DOS - since 
the interface to the radios is the same).

Joe

-- 
Joseph Mack NA3T EME(B,D), FM05lw North Carolina
jmack (at) wm7d (dot) net - azimuthal equidistant map
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Homepage http://www.austintek.com/ It's GNU/Linux!