Hi Folks:
56K packet has been running the Vancouver area for over 5 years. We have
two repeaters and a third waiting to be installed. It's on the 70 cm band.
It's a TCP/IP network, UNIX based, and fully interconnected to the Internet.
Kevin
At 06:57 PM 00/02/16 -0700, you wrote:
On Wed, Feb 16, 2000 at 04:31:51PM -0800, Ethan Dicks
wrote:
> In the 2 meter band in the U.S., at least, Hams are restricted to 1200
baud.
No, not exactly. But we are limited to the same bandwidth as an FM
voice channel, so there is a practical limit. 9600 baud fits into the
permissible deviation well enough and is commonly used on 2 meters. (Doing
true FSK rather than an audio simulation of FSK helps minimize the bandwidth
used.) More speed might be possible with the kinds of fancy tricks that
gave us 56K landline modems (and some hams experiment with that kind of
stuff).
On 440MHz and above there are some 100khz channels available. For those,
56K is the most popular high-speed mode (but pretty scarce at that). You
need a modem that outputs a 10 meter carrier pre-modulated with the signal,
and a transverter to get from there to the desired frequency; so that makes
it expensive (~$1000 to fully equip a station with new equipment) and
that's why it's not really common IMO. There have also been experiments
with 2 and 10 mbps microwave links using gunn diode transceivers and
ethernet cards and slower network cards. And now that spread-spectrum
is wide open for experimentation without any STA's required, I expect
that to be the next hotbed of activity. Most or all of the
no-license-required
wireless ethernet devices operate in ham bands (we have
to share the
bandwidth with them), so it's possible and legal to use high-gain antennae
and perhaps bigger power amps to use that kind of equipment for long-
distance links. The new regs require dynamic control of output power
though - you can't output any more power than is necessary to maintain
the link, and the control of it must be automated.
But so far the fastest I'm doing is 9600 baud (on 2 meters).
--
_______
http://www.bigfoot.com/~ecloud
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---
Kevin McQuiggin VE7ZD
mcquiggi(a)sfu.ca