🚀 go-pugleaf

On Sun, 18 Jul 2010 10:31:05 -0700, JC Dill <jcdill.lists@gmail.com>
wrote:

>Jeff Liebermann wrote:
>
>>> You recall wrong.  Circa 1992-1994 you could buy a 3 watt bag phone. 
>>> I'm told that circa 1990 you could buy a 5 watt bag phone.
>> 
>> My memory isn't perfect, but I don't recall any 5 watt bag phones.
>> There would have been considerable advertising value to offering the
>> most "powerful" phone.  
>
>My recollection of the conversation I had at the time, was that when 
>car/bag phones were first offered in the late 1980s/early 1990s, some 
>were 3 watt, some were 5 watt.  The 5 watt ones ate batteries and 
>weren't as popular with most users for that reason, then the industry 
>(or the government) decided that the phones should be capped at 3 watts 
>and the 5 watt models were discontinued.  I was told that there were 
>long-haul truckers who used the 5 watt phones to get coverage in rural 
>areas where 3 watt phones couldn't reach the distant towers.  By the 
>time I was shopping (circa 1992), I was told the 5 watt phones had been 
>discontinued for some time (more than 1 year) and if I wanted one I 
>would have to try to find it on the second-hand market (pre-craigslist).
>
>jc

I think you might be mixing technologies.  During the 1980's, long
haul truckers were using IMTS phones (and CB).  That's because the
range of an IMTS base station was 20-50 miles or more and located to
cover the highways.  Also cellular had huge gaps in rural coverage.
The down side was that the channels were few and crowded.  There may
have been some small 5 watt radios, but most were 25 watts.

The Motorola Pulsar III IMTS control head looked exactly like the
later bag phone handset.  See photo near the bottom of:
<http://www.wb6nvh.com/Carphone.htm>
Pac Hell stopped providing IMTS service in 1995, but smaller rural
RCC's (radio common carriers) continues to operate through about 2005.

Checking the FCC rules at:
<http://www.hallikainen.com/FccRules/2010/22/913/>
it proclaims:
   The ERP of mobile transmitters and auxiliary test transmitters
   must not exceed 7 Watts.
ERP (or EIRP) is "effective radiated power" which includes the gain of
the antenna.  The traditional AMPS mobile antenna has about 4dBi gain
or 2.5 times the xmitter power output equals the EIRP.  
   7 watts / 2.5 = 2.8 watts
which is where the 3 watt limit came from.  It might have been
possible to legally sell a 5 watt mobile phone, but could only be
supplied with a small 1/4 wave vertical monopole antenna.

Going back as far as possible to 1997:
<http://louise.hallikainen.org/FCC/FccRules/1997/22/913/>
This rule has not changed.

-- 
Jeff Liebermann     jeffl@cruzio.com
150 Felker St #D    http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann     AE6KS    831-336-2558