From: jab@hpuerca.atl.hp.com (Alan Barrow)
Subject: Re: Closed repeaters (FCC wants them open)
Date: Fri, 22 Jan 1993 19:00:26 GMT
Organization: Hewlett-Packard NARC Atlanta
Keywords: FCC; closed repeaters; rule change

In <C198Gw.4q5@sugar.neosoft.com> jreese@NeoSoft.com (Jim Reese) writes:


>That's not the point of linking at all.  There's no value in linking radios
>that cover the same area...the idea is to provide wide area coverage with
>the same radio system.  Linking 5 or 6 radios together that cover the same
>areas doesn't make sense.

There is value to linking repeaters in the same area, just as there is
value in voting receivers. The difference is that the linked rptrs
can also function as stand alone "cells" if there is a problem with the
other cells.

>In a city the size of Houston, for example, even a radio on a 1400 foot tower
>won't give adequate coverage of the entire metro area.  Shorter towers that 
>are close to the users works much better.

This is the situation in Atlanta. There are two approach's in use:
   voting rcvrs
   Linked "cells"

Both work well, and all are open.

>Trunking would be interesting, but it doesn't serve the same purpose as
>inter-city linking.  Trunking would increase the number of users per
>channel, but it would not necessarily improve coverage...unless you put
>the trunked channels in different locations...

Trunking can improve coverage, and allow more users. All trunks do not
have to be at the same site. They typically are not.

>I can get in my car and drive from Houston to Dallas and never lose coverage.
>This means I can get help or just talk to the friends back home during my
>entire trip.  This is the purpose of linked systems.

I can drive from 200 miles South of Atlanta to North of Knoxville Tenn
and never lose coverage from the local linked system either. All on
open machines with all the whiz bang "experimental" features available
as well.

All users can benefit from the system. It's main benefit is for travellers
along I-75. Yet only club members can bring the link up or down, or add
in ad-hoc remote base "links". Note this is not just ACC talking boxes
with IC-2A's. The RF is nearly all GE Master II's or MVP's. Many of the
links are full duplex. The Main machine has 4-6 rcv sites around metro
Atlanta. They are now playing with 10 Ghz links, with the hope of multi
channel links.

All the repeaters are open. All work is volunteer. (I designed a simple
8748 rptr controller/ID for the links.) Club dues are $20 a year, which
gets you access to the AP, DVR, and remote bases. All other functions
are open.

The main AP is open during daylight hours. This is the 1st open patch in
Atlanta for 15 years. Conventional wisdom was that open patches would be
impossible to control. It has not been a problem. As mentioned in
earlier articles, any problems were quietly and quickly dealt with.
Never did it take more than a week.

Not to say that the group does not have to deal with intermod, poor
engineering of "ham grade" equipment, etc. These are not EE's. The two
main "drivers" are high school education two way radio types. But they
keep it working, add new features, etc. 

If they can do this, why is this such a bid deal. Hmmm, I do not buy the
convoluted justifications. 

This is not rocket science, guys....


 Alan Barrow  km4ba | I've seen things you people wouldn't believe. Attack
 jab@atl.hp.com     | ships on fire off the shoulder of Orion. I watched
                    | C-beams glitter in the dark near the Tannhauser gate.
 ..!gatech!kd4nc!   | All those moments will be lost in time -
         km4ba!alan | like tears in rain. Time to die.          Roy Batty
Newsgroups: rec.radio.amateur.policy