From: Peter.Berrett@f543.n635.z3.fidonet.org (Peter Berrett)
Newsgroups: aus.radio
Subject: Citizens Band Packet Radio on 70cm
Date: Sat, 23 Jan 1993 11:51:12

 m> Now a 1200 baud TNC would cost about $200.  A type approved UHF radio
 m> costs ~$500.  That's ~$700 for a BASIC packet setup for your "CB
 m> data service".  Amateurs can do it a little cheaper by using
 m> converted commercial radios like Philips 828s etc but your CB
 m> service MUST use type approved equipment.  It's part of the "off
 m> the shelf" requirement.

 m> Now since the TNC will be connected to a type approved radio, it
 m> will probably have to be type approved too.  This means the
 m> manufacturers will have to submit their TNC designs and hardware
 m> to DoTC type approval.  An expensive business.
Hmmmm dissection time! Now first the TNC. A Baycom modem can be obtained from
the Melbourne Packet Radio group with software for as little as $125. As for
the question of tranceivers, yes the equipment is not available at present
however once the standards were laid out it would not be difficult for
manufacturers to change the circuit designs of current radios to suit packet.
Granted the DOTC approval would be a hitch but current cb manufacturers do it
now already so it must be possible. If say the cb band was on vhf instead, then
current handheld for vhf area are available for as little as $299 new. The
modification for packet use and frequency change would not be that difficult.
So the total cost to the user would be more in the order of between $425 and
$500 which for many computer users would be acceptable.
 
 m> Now, lets look at actually using this CB data service.  You are
 m> restricted to using 1200 baud HALF DUPLEX with, at best, a
 m> throughput of around 80 CPS (taking into account timing delays,
 m> acks etc).  As soon as multiple users appear on the channel your
 m> throughput drops dramatically.  You can't use Maximus, QuickBBS,
 m> OPUS or any standard Fidonet BBS program on packet.  All these
 m> and all telephone BBSs these days expect FULL DUPLEX operation
 m> with minimal delays on the transmission path.  They don't work
 m> well with HALF DUPLEX paths and transmission times around 5
 m> seconds, double it for each digipeater in the path.  I KNOW this
 m> is true as I attempted to run both QuickBBS and Maximus on air
 m> alongside my Packet BBS system.  With a lot of pain I got
 m> QuickBBS to work but it didn't like it.
 
Yes its slow but hence the need for a large number of channels.  The greater
the number of channels and the lower the power output of tranceivers combined
with the encouraged use of directional antennas results in less collisions,
less interference to third parties and less dogpiles.
 
 m> Packet BBS programs such as F6FBB and W0RLI are not compatable
 m> with Fidonet BBSs, or in fact with *any* other messaging system
 m> in the world. :-(  You have to have extra software to convert
 m> between formats.  The packet BBS system does not handle a lot of
 m> messages well.  The content of even 1 Echomail conference such as
 m> LTUAE, SF, AUST_SYSOP even, would totally swamp the packet
 m> system.

 m> Compared to Fidonet BBSs and similar technology the Packet BBS
 m> system is unfriendly, slow, and lacking in features.  There isn't
 m> even a standard file transfer protocol.  There are a number of
 m> protocols around such as YAPP and the BAYCOM protocol but XMODEM
 m> and ZMODEM and their ilk DO NOT WORK properly over packet radio.
 
The standard file protocol could be set down in the standards laid down by
DOTC. These standards would also set out the bbs software to be used as normal
communication software. As new products appear on-line ( and they would ) they
could be inorporated into the standards. As for the messaging problem this
could be overcome by the use of special interbbs channels that update on a more
or less continuous vasis thus the volume isn't sent in one hit but gradually
over the day. Probablt an entirely separate messaging network would need to be
set up with gateways to fido net for specific purposes.
 
 m> So, in summary.  If you want to use packet radio to access
 m> Fidonet telephone BBSs then think again as it's not going to
 m> work.  The BBS are not designed for it.  Packet BBSs do not have
 m> the capabilities most users expect out of telephone BBSs and so
 m> will not be a good substitute.  Setting yourself up to operate
 m> packet is expensive, just as expensive, if not more than setting
 m> yourself up to use a telephone BBS.  Throughput is low and the
 m> BBSs less responsive due to the way packet works.

 m> As a final note there are two more points to consider, 

 m> 1) you will still need a licence to use this "CB data service"
 m> The CB service has a licence fee for using it.  It's based on the
 m> number of transmitters and is currently $18 for each.

 m> and 

 m> 2) what sysop is going to provide this service for you to use? 
 m> Very few sysops are going to want to go to the expense of
 m> purchasing a type approved radio and a TNC just to make it
 m> cheaper for the users to logon, when he already has to have the
 m> telephone modem to exchange mail with other BBSs.  The user
 m> telephone costs don't effect him, most BBSs are user-pays
 m> anyway!  
 
 Ok so it will cost $18 but that's only the equivalent of 72 phone calls
(local). As for the sysop, I've already had one sysop reply that he liked the
idea and would be prepared to hook his board up. If the standards etc were set
up, I'm sure that there are many sysops who'd like to become involved.
Peter Vk3KAT (Meiouw!)

 * Origin: JKARC BBS Melbourne (03) 521-1206 (3:635/543)