[pct-l] LongPost: Cell & Sat Phones, 2 meter HAM, and ELTs

[Brick Robbins <brick@ix.netcom.com>]

Here is what I know about various communication systems that might be of
use on the PCT. An understanding of how each works might help one to decide
which to carry, if any. 

Due to my job and hobbies, I am familiar with comm systems, but I am not an
expert, so if any listers have more accurate info, please share with us.

Cell Phones *****

A cell phone is a very short range radio that can transmit on several
different "channels." By making the range of each phone small, a region can
have several different phones working on the same channel without
interfering with each other (the primary goal of a cellular sytem). The
phones talk to closely spaced base-stations - the area around each
base-station is known as a "cell." A computer controls the phones and
base-stations and determines which phone talks to which base-station on
which channel. 

Because of the design of a cellular system, 100% coverage is almost
impossible. The base-stations need to be too close together (a few miles)
and line of sight. The current grid only covers major roads and urban
areas. That leaves out huge sections of the PCT.

The cell phone will only work if you can see a major road or town, and you
are within a few miles of it. Most of So-Cal should be OK, but even a
"major" Sierra re-supply point like Kennedy Meadows has no  coverage (at
least in '95 when I was there - no land lines either).

Once you hit the mountains, mail your phone home...

Satellite Phones*****

I have experience with old sat-phones (big and heavy) but the Iridium phone
system is new, all I know about it I learned from their advertising. The
system is a combination of cell technology, and a satellite system. You can
connect to most cell systems, and if you are out of range, you use a
constellation of low orbiting satellites similar to the GPS constellation.

GPS is almost useless in the deep valleys along the PCT due to mountains
blocking the satellite signals.  An attempt at GPS mapping the PCT in the
northern Sierra proved to be extremely difficult because GPS worked only a
few minutes of each hour. This is only a guess and this problem may not
exist with the Iridium (1 satellite for Iridium vs 3 for GPS), but I dunno. 

The hand set costs about $1500, and the satellite connect time runs about
$10/min so you will have to want to talk awfully bad to use the thing.

2 meter HAM*****

This is a high power (compared to cell), line of sight system. The number
of "channels" is limited, so only a small number of users can be active at
the same time and everyone on the channel can hear. The line of sight
limitation is overcome by placing base-stations on top of tall mountains
that receive then rebroadcast any signals (called "repeaters"). In order to
use a system in a remote area, you need to know if there is a repeater
within range, and what channel it operates on. The list of public use
repeaters is published. Some repeaters are hooked into the telephone
system, so if you know the access codes, you can make phone calls.

For a 2 meter to work as an emergency communication tool, there needs to be
someone listening on the same channel you are broadcasting.  I dunno what
they cost these days. I'm sure someone on the list does.

Emergency Locator Transmitter (ELT)***

This is a small transmitter that is carried by aircraft and ships that
transmits a "come and get me" signal on frequencies monitored by aircraft,
satellites, and ground stations - works great. Some also have talk/listen
ability to communicate with any search and rescue planes that come looking
for you (no link with the satellites, though...). Light weight versions for
backcountry travelers are available. If you are looking for a "safety net"
radio, this is probably the one to get. Costs a couple hundred bucks


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