In article , Steve Terry
scribeth thus

"tony sayer" wrote in message
...
In article , Steve Terry
scribeth thus
"Rupert Moss-Eccardt" wrote in message
...
Steve Terry wrote:
"tony wrote in message
...
In , Steve Terry
scribeth thus
"Roy wrote in message
...
On 22 Sep, 11:55, wrote:
"Roy wrote in message



On 22/09/10 11:24, Recliner wrote:
snip
Trower report:
http://www.tetrawatch.net/papers/trower_report.pdf

Some really good science there eh;?....
snip

Yes it's very suspect science, but there is little doubt that unnecessarily
multiplexing at 17.6Hz could have been a completely avoidable health risk

In 2000 whist visiting Sweden i spoke to police officers about
their new GSM Pro personal radios (at the time using waterproof
Ericsson R250s) and they were very satisfied with them.
(retail price for Ericsson R250s at the time was around £100 each)
http://www.gsmarena.com/ericsson_r250s_pro-119.php

These 450 MHz versions?. With PPT I presume?..


900MHz on existing public GSM networks with high priority GSM Pro sims
With closed group PTT

Yes that doesn't seem that clever from what I hear..

And they don't want to rely on public nets either..

Also if required additional encryption can be added to each phone.

I thought that GSM was well encrypted as it was?..

Debatable

Sufficient for practical purposes..



We of course years later had to reinvent the wheel, at the cost of
billions
to the public for the benefit of private companies, and to the detriment
of the public allowing them to share an improved GSM network.

Are you suggesting that the public shared a security network?..
Tony Sayer


Why not, it works for them, and if you think about it, most UK police
personal comms has for years already been over officers personal
GSM phones on the public network, especially still in Tetra poor
signal black spot areas.

And of course mobile phones don't have any then;?..


The added advantage to Scandinavian public, is that areas where
emergency services have poor GSM signal get priority for additional
cells to strengthen the existing network, so everyone wins.

In the early days of Tetra if it wasn't for officers being able to
fall back on their GSM phones, Tetra's many black spot areas,
would have made it fail.

Come on, there are many and still are several areas where GSM is ****
poor..


Also some UK police services have been using Blackberrys over
public GSM networks for collating data.
No one has questioned any security issues about police using the
public networks

The one thing that has worried me about officers unbridled use of
GSM phones is that where their PRs calls are recorded for
evidential later use, of course their phones aren't.

Perhaps that a good thing from the bobbies POV;!..

Steve Terry

--
Tony Sayer

"Phil W Lee" wrote in message
...
tony sayer considered Sun, 26 Sep 2010 22:16:53
+0100 the perfect time to write:

In article , Steve Terry
scribeth thus

"tony sayer" wrote in message
...
In article , Steve Terry
scribeth thus
"Rupert Moss-Eccardt" wrote in message
...
Steve Terry wrote:
"tony wrote in message
...
In , Steve Terry
scribeth thus
"Roy wrote in message
...
On 22 Sep, 11:55, wrote:
"Roy wrote in message



On 22/09/10 11:24, Recliner wrote:
snip
In the early days of Tetra if it wasn't for officers being able to
fall back on their GSM phones, Tetra's many black spot areas,
would have made it fail.

Come on, there are many and still are several areas where GSM is ****
poor..

See first point above
There probably wouldn't be nearly as many poor GSM areas if a tiny
fraction of the considerable sums spent on TETRA had been spent on
filling in GSM holes.


Clearly there are two distinct points of view, one that stifled cellular PTT
offers cheap and practical closed group comms for the benefit of all users,
and two those with a vested interest in perpetrating the vast bureaucracy
and £Billion budgets of Tetra that didn't exist ten years ago, and are
looking forward to a replay with even bigger budgets and careers
to be made with the future planned Tetra 2.

Meanwhile on the streets, emergency services will continue to fall back
on their mobile phones for calls, and Blackberrys for correlating data.

and with PTT apps appearing on the latest generation of Android phones
no doubt emergency services will find new uses for them too.

Steve Terry
--
"I would like to plead for my right to investigate natural phenomena
without having guns pointed at me.
I also ask for the right to be wrong without being hanged for it."
- Wilhelm Reich, November 1947

Steve Terry wrote:

Clearly there are two distinct points of view, one that stifled cellular PTT
offers cheap and practical closed group comms for the benefit of all users,
and two those with a vested interest in perpetrating the vast bureaucracy
and £Billion budgets of Tetra that didn't exist ten years ago, and are
looking forward to a replay with even bigger budgets and careers
to be made with the future planned Tetra 2.

GSM can't do the sort of PTT that is required by the emergency services.
I suppose you could design something on top but it wouldn't really be
GSM anymore. One of the fundamental problems is the fact that GSM takes
a while for call set up.

Meanwhile on the streets, emergency services will continue to fall back
on their mobile phones for calls, and Blackberrys for correlating data.

It is true that reactive police typically carry and use GSM handsets and
Blackberrys but that is only one of many different emergency services or
even functions within the police.

"Rupert Moss-Eccardt" wrote in message
...
Steve Terry wrote:

Clearly there are two distinct points of view, one that stifled cellular
PTT
offers cheap and practical closed group comms for the benefit of all
users,
and two those with a vested interest in perpetrating the vast bureaucracy
and £Billion budgets of Tetra that didn't exist ten years ago, and are
looking forward to a replay with even bigger budgets and careers
to be made with the future planned Tetra 2.

GSM can't do the sort of PTT that is required by the emergency services.
I suppose you could design something on top but it wouldn't really be
GSM anymore. One of the fundamental problems is the fact that GSM
takes a while for call set up.


I believe Orange's PTT ran over GPRS data which is left running
near enough continuously.

Skype on Three i leave running continuously whilst minimised,
sometimes for weeks on end.

Steve Terry
--
"I would like to plead for my right to investigate natural phenomena
without having guns pointed at me.
I also ask for the right to be wrong without being hanged for it."
- Wilhelm Reich, November 1947

On Wed, 29 Sep 2010, Steve Terry wrote:

"Rupert Moss-Eccardt" wrote in message
...
Steve Terry wrote:

Clearly there are two distinct points of view, one that stifled
cellular PTT offers cheap and practical closed group comms for the
benefit of all users, and two those with a vested interest in
perpetrating the vast bureaucracy and ?Billion budgets of Tetra that
didn't exist ten years ago, and are looking forward to a replay with
even bigger budgets and careers to be made with the future planned
Tetra 2.

GSM can't do the sort of PTT that is required by the emergency
services. I suppose you could design something on top but it wouldn't
really be GSM anymore. One of the fundamental problems is the fact
that GSM takes a while for call set up.

I believe Orange's PTT ran over GPRS data which is left running
near enough continuously.

Skype on Three i leave running continuously whilst minimised, sometimes
for weeks on end.

Presumably, providing universal 3G coverage to the emergency services
would be an entirely different kettle of fish. Very expensive fish.

tom

--
Mpreg is short for Male Impregnation and I cannot get enough. -- D

In article , Steve Terry
scribeth thus

"Phil W Lee" wrote in message
.. .
tony sayer considered Sun, 26 Sep 2010 22:16:53
+0100 the perfect time to write:

In article , Steve Terry
scribeth thus

"tony sayer" wrote in message
...
In article , Steve Terry
scribeth thus
"Rupert Moss-Eccardt" wrote in message
.. .
Steve Terry wrote:
"tony wrote in message
...
In , Steve Terry
scribeth thus
"Roy wrote in message

...
On 22 Sep, 11:55, wrote:
"Roy wrote in message



On 22/09/10 11:24, Recliner wrote:
snip
In the early days of Tetra if it wasn't for officers being able to
fall back on their GSM phones, Tetra's many black spot areas,
would have made it fail.

Come on, there are many and still are several areas where GSM is ****
poor..

See first point above
There probably wouldn't be nearly as many poor GSM areas if a tiny
fraction of the considerable sums spent on TETRA had been spent on
filling in GSM holes.


Clearly there are two distinct points of view, one that stifled cellular PTT
offers cheap and practical closed group comms for the benefit of all users,
and two those with a vested interest in perpetrating the vast bureaucracy
and £Billion budgets of Tetra that didn't exist ten years ago, and are
looking forward to a replay with even bigger budgets and careers
to be made with the future planned Tetra 2.

Meanwhile on the streets, emergency services will continue to fall back
on their mobile phones for calls, and Blackberrys for correlating data.


I asked a policeman I know re this the other day and the Airwave works
fine and yes, he sometimes uses his mobile but for different reasons..


and with PTT apps appearing on the latest generation of Android phones
no doubt emergency services will find new uses for them too.

Steve Terry

--
Tony Sayer

Is it possible to hear London Underground radio transmissions on a
regular scanner now?

wrote in message
...

Is it possible to hear London Underground radio transmissions on a regular
scanner now?

No, they now use a version of digitally encrypted Tetra

Google Tetra TFL

Steve Terry
--
"I would like to plead for my right to investigate natural phenomena
without having guns pointed at me.
I also ask for the right to be wrong without being hanged for it."
- Wilhelm Reich, November 1947

On 30/09/2010 17:42, Steve Terry wrote:
wrote in message
...

Is it possible to hear London Underground radio transmissions on a regular
scanner now?

No, they now use a version of digitally encrypted Tetra

Google Tetra TFL

Steve Terry
What about National Rail?

wrote in message
...
On 30/09/2010 17:42, Steve Terry wrote:
wrote in message
...

Is it possible to hear London Underground radio transmissions on a
regular
scanner now?

No, they now use a version of digitally encrypted Tetra

Google Tetra TFL
Steve Terry

What about National Rail?

They tend to use GSM-R
http://en.wikipedia.org/wiki/GSM-R

Steve Terry
--
"I would like to plead for my right to investigate natural phenomena
without having guns pointed at me.
I also ask for the right to be wrong without being hanged for it."
- Wilhelm Reich, November 1947