Ham population stats

On Wed, Feb 16, 2000 at 04:31:51PM -0800, Ethan Dicks wrote: 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 (_ | |_) ecloud(a)bigfoot.com finger rutledge(a)cx47646-a.phnx1.az.home.com __) | | \__________________________________________________________________