From: robert@Xenon.Stanford.EDU (Robert Kennedy)
Subject: Re: Bike to bike communication
Summary: Grab this, Loki! It's almost a review!
Keywords: Maxon 49-HX Communicator
Organization: Computer Science Department, Stanford University.
Date: Thu, 21 Jan 1993 21:04:33 GMT

In article <C17JJu.588@unix.amherst.edu> nrmendel@unix.amherst.edu
(Nathaniel Mendell) writes:
> What's the best form of electronic communication between bikes? CB or one of
> those 2-way fm deals? I'm told that some models have microphones inside
> the earphone -- how do those work on bikes? What's range like for a compact
> (mount inside fairing?) unit? Prices? Good brand names?

I can comment in only a limited way, since the use I've put my Maxon
49-HX communicator to is limited, but here goes. I've used the
communicator only as a helmet-to-helmet intercom to talk with a
passenger. For that purpose, it's OK. To use the unit as I have, you
have to buy an auxilliary headset for your passenger. I don't remember
the item prices, but the whole thing cost a bit over $100. I wear a
Shoei RF-200. I normally wear the unit on my belt so my passenger can
reach the push-to-talk button (see below), but it would easily fit in
a fairing pocket.

What I know: The microphones probably don't stand a chance of working
with open-face helmets, since they're standard stiff-wire-mounted
front-of-the-mouth jobs. With a full face helmet, they work great. The
speaker velcros into the inside of your helmet, and stays put pretty
well. The voice activation circuit is useful only if your speed is
keeping pretty constant, since the noise level changes so much with
speed. I prefer push-to-talk operation myself, since there's a button
that velcros onto the left bar, and my passenger can push the button
on the main unit mounted on my belt. The unit has two settings, and
they're a little bizarre. One is nominally the "intercom" setting, and
the other is nominally the "radio" setting. On the intercom setting,
the volume control adjusts the radio volume only, so you can still
*listen* to other bikes, baby monitors, etc. But when you talk, no
transmission occurs. Also, in the intercom position, when the "talk"
circuit is activated, both microphones (rider and passenger) are
active, and both can talk and hear each other, just a like a phone.
The intercom volume is not adjustable. I thought this would be a big
problem, and even though it still annoys me, it really isn't a
problem. It's easy to hear clearly both with and without earplugs, at
all speeds below about 90mph. In "radio" mode, the volume control
still adjusts the radio volume, and when you talk, your (the rider's)
microphone signal is transmitted to any other bikes in the area on the
same channel. The passenger's microphone is dead in radio mode. The
radio section transmits and receives on any one of 5 different
channels.

There is no way to:
	1) Hear your passenger when in radio mode, nor to transmit
	   your passenger's voice over the airwaves;
	2) Turn off the radio receiver when in intercom mode (though
	   you can turn it all the way down, it still uses the
	   batteries);
	3) Adjust the volume of the intercom signal;
	4) Talk and listen on different frequencies, thereby affording
	   a slight privacy enhancement when communicating with
	   someone who's doing the same; or
	4) Understand why any of these restrictions exists. They are
	   all annoying and unjustified.

There is almost no way to:
	1) Change any of the controls while moving, except to use
	   either of the two push-to-talk buttons. Changing from radio
	   to intercom, for example, is pretty much right out if you
	   have gloves on.
	2) Be sure that the unit will neither turn off suddenly nor
	   bother you with radio interference when in intercom mode.
	   In other words, if, in an attempt to avoid hearing the
	   radio receiver section while in intercom mode, you turn the
	   volume down, you run the risk that vibration will actually
	   press the volume knob that 1mm further to turn the power
	   off.

What I don't know: How good the radio transmitter section is. The
receiver section picks up cordless phones and baby monitors really
well. I haven't used this communicator in a multi-bike application
yet.

All in all, it makes touring riding a lot more tolerable to this
predominantly sport motorcyclist, at least when I have a passenger.
This way I don't freak out from boredom quite so badly when I get
stuck behind the unpassable garbage truck... At the same time, to use
it when riding sporty, you have to have a little extra measure of
trust in your passenger. It takes a little getting used to before you
can handle hearing *anything* from your passenger when you're using
100% of your concentration to set up for a tough corner. If you can't
trust your passenger not to say "WATCH OUT!" or "GEE, IS THAT ICE?!?"
at an inopportune time and you can't handle it when they do, TURN THE
INTERCOM OFF WHEN SPORT RIDING.

	-- Robert

Robert Kennedy					(415) 723-4532 (office)
robert@cs.stanford.edu				(415) 322-7367 (home voice)
Computer Science Dept., Stanford University	(415) 322-7329 (home tty)
Newsgroups: rec.motorcycles