full-duplex 802.11?

[Jean Tourrilhes]

Bruce Janson wrote :
> Now that sub-frequency selectable wireless devices are common, has anyone
> tried to set up full-duplex point-to-point links?  I would imagine that
> this could be done using two wireless cards at each end (i.e. four cards
> in total).  At each end, both cards would be attached to the same antenna
> (via some sort of "splitter/combiner" Y-shaped junction).  Each card would
> be tuned to a separate sub-frequency (and of course, that sub-frequency would
> match that of the corresponding card at the remote end).  Then traffic in
> one direction would be sent through one network interface (sub-frequency)
> and that in the other direction confined to the other channel.

	Have you ever seen the shape of a transmitted radio signal
(versus frequency) ? It looks more or less like a gaussian
curve. Which mean that even if you don't transmit a full power in the
adjacent channel, you will transmit enough to "blind" you.
	Using the same antenna is "no way". I even suspect that
electrically you can damage your cards. Using two different pair of
antennas might be possible but you will need to position the Rx
antenna properly with respect to the Tx antenna (check your angular
response).
	Good luck...

	Jean