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
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Joseph Mack NA3T EME(B,D), FM05lw North Carolina
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