Two way pagers

Clive said:

Being an experienced 'solo' walker, I am fully aware of my own safety. As I walk mainly in
Scotland, I am looking at alternatives to mobile phones (as a signal is often not available).

This brought me to pagers. What about a old type pager working in reverse - allowing me to send a
pre-defined message to a friend/family member (landline or mobile) informing them that I'm fine or
in need of assistance.

Does anyone know of such a device?

Clive

Cognito messengers are one option but you will need a good signal to send message back

cognitoltd.comcognitoltd.comOpen ↗

Clive said:

Being an experienced 'solo' walker, I am fully aware of my own safety. As I walk mainly in
Scotland, I am looking at alternatives to mobile phones (as a signal is often not available).

One thing you can do (but probably shouldn't 😉 is to get a collapsible yagi antenna and mod your
phone so it'll connect to an external antenna. This will give you considerable range extension but
you will need to know where you are and where the cellsites are so you can point your antenna at
them. This does work, we've done it in several places in Scotland.

Quoted message said:

This brought me to pagers. What about a old type pager working in reverse - allowing me to send a
pre-defined message to a friend/family member (landline or mobile) informing them that I'm fine or
in need of assistance.

Does anyone know of such a device?

You'll probably get better coverage from GSM than from two-way paging services. I don't know if
Cognito are still going but SMS has pretty much all the market. If you really can't get GSM then you
may have to consider thing like Orbcomm messagers which rely on polar orbiting satellites so can
have upto 90 minutes of delay or satellite phones like the Iridium system.

Chris
--
Chris Eilbeck "][email hidden]

"Clive" <[email hidden]> wrote in message news:<[email hidden]>...

Quoted message said:

Being an experienced 'solo' walker, I am fully aware of my own safety. As I walk mainly in
Scotland, I am looking at alternatives to mobile phones (as a signal is often not available).

This brought me to pagers. What about a old type pager working in reverse - allowing me to send a
pre-defined message to a friend/family member (landline or mobile) informing them that I'm fine or
in need of assistance.

Does anyone know of such a device?

Clive

Satellite phones (Ericsson R290) are available for around £200. Should get a signal anywhere in the
UK (and most of the rest of the World!). See www.r290.net or ebay.

"Chris Eilbeck" <[email hidden]> wrote

Quoted message said:

You'll probably get better coverage from GSM than from two-way paging services.

Quite true.

Quoted message said:

I don't know if Cognito are still going but SMS has pretty much all the market.

And it's pretty robust, you can send SMS when there is no chance of making a voice call.

Quoted message said:

If you really can't get GSM then you may have to consider thing like Orbcomm messagers which rely
on polar orbiting satellites so can have upto 90 minutes of delay or satellite phones like the
Iridium system.

These must be seriously large polar orbits, about as far away as Pluto. For comparison, the moon is
slightly over a light second away and the sun only about eight minutes.
--
Mark South: Citizen of the World, Denizen of the Net

Mark South said:

"Chris Eilbeck" <[email hidden]> wrote

Quoted message said:

You'll probably get better coverage from GSM than from two-way paging services.

Quite true.

Quoted message said:

I don't know if Cognito are still going but SMS has pretty much all the market.

And it's pretty robust, you can send SMS when there is no chance of making a voice call.

Quoted message said:

If you really can't get GSM then you may have to consider thing like Orbcomm messagers which
rely on polar orbiting satellites so can have upto 90 minutes of delay or satellite phones like
the Iridium system.

These must be seriously large polar orbits, about as far away as Pluto. For comparison, the moon
is slightly over a light second away and the sun only about eight minutes.

😉 There aren't many sats, sometimes you need to wait for a pass like you used to have to with
getting a position from transit sats.

Chris
--
Chris Eilbeck "][email hidden]

Chris Eilbeck said:

"Clive" <[email hidden]> writes:

Quoted message said:

Quoted message said:

Being an experienced 'solo' walker, I am fully aware of my own safety. As I walk mainly in
Scotland, I am looking at alternatives to mobile phones (as a signal is often not available).

Quoted message said:

One thing you can do (but probably shouldn't 😉 is to get a collapsible yagi antenna and mod your
phone so it'll connect to an external antenna. This will give you considerable range extension but
you will need to know where you are and where the cellsites are so you can point your antenna at
them. This does work, we've done it in several places in Scotland.

But for timing reasons it won't work beyond the standard 35km timing limit, except for those rare
coastal stations which use a 70km timing limit, exchanging bandwidth for range.

Do you really need to know where the station is? Why can't you just turn round slowly in a circle?

Do you really need the extra gain from a pointable yagi? Wouldn't a standard omni-directional larger
vertical antenna, such as used externally on cars, be all that was required, given the 35/70km range
restriction due to timing?

--
Chris Malcolm [email hidden] +44 (0)131 651 3445 DoD #205
IPAB, Informatics, JCMB, King's Buildings, Edinburgh, EH9 3JZ, UK
["]http://www.dai.ed.ac.uk/homes/cam/]

I don't think they have any coverage in the Highlands.

Quoted message said:

Cognito messengers are one option but you will need a good signal to send message back

"Chris Malcolm" <[email hidden]> wrote in message
"]news:[email hidden]...

Quoted message said:

Chris Eilbeck said:

"Clive" <[email hidden]> writes:

Quoted message said:

Quoted message said:

Being an experienced 'solo' walker, I am fully aware of my own safety. As I walk mainly in
Scotland, I am looking at alternatives to mobile phones (as a signal is often not available).

Quoted message said:

One thing you can do (but probably shouldn't 😉 is to get a collapsible yagi antenna and mod your
phone so it'll connect to an external antenna. This will give you considerable range extension

but

Quoted message said:

Quoted message said:

you will need to know where you are and where the cellsites are so

you

Quoted message said:

Quoted message said:

can point your antenna at them. This does work, we've done it in several places in Scotland.

But for timing reasons it won't work beyond the standard 35km timing limit, except for those rare
coastal stations which use a 70km timing limit, exchanging bandwidth for range.

In principle, and according to the spec, it should not work due to the timing reasons you mention.

Given how loosely most of the specs are implemented, you may be able to get away with huge timing
errors. There's an outfit in Sweden (spoke briefly with them at Telecom 2003) building extenders
that send the signal down railway lines several hundred kilometres and back. They get away with it
quite neatly, and haven't mentioned any timing issues.

Quoted message said:

Do you really need to know where the station is? Why can't you just turn round slowly in a circle?

Do you really need the extra gain from a pointable yagi? Wouldn't a standard omni-directional
larger vertical antenna, such as used externally on cars, be all that was required, given the
35/70km range restriction due to timing?

Or have a base station ham operator listening on your channel and carry the correct squawker beacon.
They can then phone for help once you activate the beacon.

OBTW :-)
--
Mark South: Citizen of the World, Denizen of the Net

(Chris Malcolm) said:

Chris Eilbeck said:

"Clive" <[email hidden]> writes:

Quoted message said:

Quoted message said:

Being an experienced 'solo' walker, I am fully aware of my own safety. As I walk mainly in
Scotland, I am looking at alternatives to mobile phones (as a signal is often not available).

Quoted message said:

One thing you can do (but probably shouldn't 😉 is to get a collapsible yagi antenna and mod your
phone so it'll connect to an external antenna. This will give you considerable range extension
but you will need to know where you are and where the cellsites are so you can point your antenna
at them. This does work, we've done it in several places in Scotland.

But for timing reasons it won't work beyond the standard 35km timing limit, except for those rare
coastal stations which use a 70km timing limit, exchanging bandwidth for range.

You're probably right. I know they use timing advance but I'm not so sure of the limits of cell
sizes. We were doing this in the valley north of Ben Lomond but south of the Loch Arklet reservoir
where there is absolutely no cellphone coverage to a handheld on any network.

Quoted message said:

Do you really need to know where the station is? Why can't you just turn round slowly in a circle?

It's just one thing that's easy to know in advance, you know, taking an unknown out of the
experiment.

Quoted message said:

Do you really need the extra gain from a pointable yagi? Wouldn't a standard omni-directional
larger vertical antenna, such as used externally on cars, be all that was required, given the
35/70km range restriction due to timing?

The antennas on phones are truly pants so replacing it with just a monopole will give a big range
improvement. A 8-10 element yagi would be easy to fit in the average daysack and could easily give
40% range extension over a phone fitted with a 1/4 wave monopole.

Chris
--
Chris Eilbeck "][email hidden]

On Wed, 3 Mar 2004 11:29:26 +0000 (UTC), [email hidden] (Chris

Malcolm) said:

Chris Eilbeck said:

"Clive" <[email hidden]> writes:

Quoted message said:

Quoted message said:

Being an experienced 'solo' walker, I am fully aware of my own safety. As I walk mainly in
Scotland, I am looking at alternatives to mobile phones (as a signal is often not available).

Quoted message said:

One thing you can do (but probably shouldn't 😉 is to get a collapsible yagi antenna and mod your
phone so it'll connect to an external antenna. This will give you considerable range extension but
you will need to know where you are and where the cellsites are so you can point your antenna at
them. This does work, we've done it in several places in Scotland.

Not a bad idea and a yagi for 1.8Ghz isn't going to be very big either! Best keep the feedline short
though to minimise loss.

Quoted message said:

But for timing reasons it won't work beyond the standard 35km timing limit, except for those rare
coastal stations which use a 70km timing limit, exchanging bandwidth for range.

Do you really need to know where the station is? Why can't you just turn round slowly in a circle?

Do you really need the extra gain from a pointable yagi? Wouldn't a standard omni-directional
larger vertical antenna, such as used externally on cars, be all that was required, given the
35/70km range restriction due to timing?

Remember that a car set uses about 7W into the aerial where a handset probably only runs 300mW

--
79.84% of all statistics are made up on the spot. The other 42% are made up later on. In Warwick -
looking at flat fields and that includes the castle.

On 03 Mar 2004 20:31:15 +0000, Chris Eilbeck <[email hidden]>

Quoted message said:

(Chris Malcolm) said:

Chris Eilbeck said:

"Clive" <[email hidden]> writes:

Quoted message said:

> Being an experienced 'solo' walker, I am fully aware of my own safety. As I walk mainly in
> Scotland, I am looking at alternatives to mobile phones (as a signal is often not available).

Quoted message said:

One thing you can do (but probably shouldn't 😉 is to get a collapsible yagi antenna and mod
your phone so it'll connect to an external antenna. This will give you considerable range
extension but you will need to know where you are and where the cellsites are so you can point
your antenna at them. This does work, we've done it in several places in Scotland.

But for timing reasons it won't work beyond the standard 35km timing limit, except for those rare
coastal stations which use a 70km timing limit, exchanging bandwidth for range.

You're probably right. I know they use timing advance but I'm not so sure of the limits of
cell sizes.

The spec is 36km across the cell, they like to run no more than 30km. Offshore ones have different
settings as noted, although the base typically will not listen to transceivers on land, you will get
serviced by a different cell on the 36km limit.

--
79.84% of all statistics are made up on the spot. The other 42% are made up later on. In Warwick -
looking at flat fields and that includes the castle.

They barely have coverage in the city !!!

Rubbish !

"MB" <[email hidden]> wrote in message "]news:[email hidden]...

Quoted message said:

I don't think they have any coverage in the Highlands.

Quoted message said:

Cognito messengers are one option but you will need a good signal to

send

Quoted message said:

Quoted message said:

message back