Path: utzoo!attcan!uunet!fernwood!apple!well!nagle
From: nagle@well.sf.ca.us (John Nagle)
Newsgroups: comp.robotics
Subject: Re: Wireless Computer Communication
Message-ID: <18150@well.sf.ca.us>
Date: 25 May 90 06:15:27 GMT
References: <9352@pt.cs.cmu.edu> <$B^$N*%@ads.com>
Reply-To: nagle@well.sf.ca.us (John Nagle)
Lines: 26

In article <$B^$N*%@ads.com> pkahn@ADS.COM (Philip Kahn) writes:
>In article <9352@pt.cs.cmu.edu> gerry@cive.ri.cmu.edu (Gerry Roston) writes:
>>Here's a problem we are all probably familiar with:  how
>>to communicate with a mobile robbot without using a tether.
>An easy and relatively cheap kluge is to use cordless phones and
>standard modems (digital data only).  Low bandwith and need to
>compress and transfer images slowly is the user's responsibility...

      Not legal.  Cordless phones are type-approved, and user mods
are prohibited.  See 47 CFR 15.235.

      It's possible to use the type-approved RF modules which form
part of some R/C gear to build a two-way system.  I've done this, and
it's painful to get it to work.   I don't recommend it.  The receivers
are designed for the pulse train waveform that R/C systems use, and don't
work well with other waveforms.

      Even the high-end approach of getting FM TV microwave gear doesn't
work all that well indoors when the transmitter is moving.  The reflection
nulls get you.  A diversity receiver is required.

      But the way to go is probably to look into wireless LANs, of which
there are now several on the market.  Any info would be appreciated.

					John Nagle
					KA2XXF (experimental, not ham)