> I am curious if it is possible to use two fax
> machines on both ends of the communication
> between two amateurs (no phone line is involved).
In short, maybe, but not really.
While fax is a valid mode (
http://www.hffax.de/,
for example), I'm afraid that making two generic
fax machines work with a pair of ham rigs might
be a bit difficult.
Most fax machines will not start a transmission if
there is no dialtone. Further, you'd need to figure
out how to key the respective radios for the
handshaking startup sequence. I'm sure it's possible
but I haven't seen any plans for making such an
interface nor a place to buy one.
You're also going to run into some bandwidth
limitations. Most fax machines run at 9600 bps
and can drop back to 4800, 2400 and 1200 bps
based on line conditions. Some high speed fax
machines can do 144,000 bps but that is more
unusual. On VHF/UHF, 9600 bps is legal (right?).
In HF, I think you'll be more limited.
Matt (k4mls)