Move to keep Analog Cell Phones

"Donald Newcomb" <[email protected]> wrote in
news:[email protected]:

> Once upon a time I was in the Mediterranean, working on and off the
> coast of Italy. I had a little 4-element, 900 MHz Yagi to help and had
> all sorts of "bars" but as soon as we hit 18 nm off the coast it was
> like a brick wall. All the bars in the world didn't help. Needless to
> say, they didn't have ER GSM.
>
>

I sail on a French-made Amel Sharki 41' ketch along the southeast coast of
USA. I have a Decibel Products 800 Mhz, 11 element yagi that's end-
mounted, made for 800 Mhz paging relay service from a paging friend. It's
very broadbanded at this band. SWR is 1.15:1 across cellular after a
little tuning of the gamma match on it.

When I had Verizon's AMPS online, hooked to a 3W Motorola bagphone running
off ship's 12VDC house batteries, service was near perfect with the beam
hauled up the mast and pointed towards shore at 55' for about 45-50 miles
offshore. Every offshore sailor should be carrying a 99 cent thrift store
bagphone, even if they won't let you put it on the air! With the little
beam, it works farther than VHF marine usually does and can dial 911 by
law. Our boat has one that's not provisioned for emergency comms...another
backup.



--
Larry

---

› See More: Move to keep Analog Cell Phones

"Quick" <[email protected]> wrote in
news:[email protected]:

> Timing. Propagation delay over that distance gets too large.
>
> -Quick
>
>

The other problem, on land, is the multipath delays, the same physics that
causes terrible "ghosts" on UHF TV at any distance without a very
directional antenna, i.e. your little cellphone antennas. Data
transmissions, even these really slow ones, is torn apart when the direct
signal and another signal that has bounced off a building or mountain or
AIRPLANE OVERHEAD comes in later than the main signal.

When multipath occurs on FM, whether it's FM radio or FM 2-way or AMPS,
you'll hear the multipath cause the analog FM signal to fade in and out in
the fringe areas as the long path signal reinforces, then a little later
opposes the main signal. Your FM broadcast radio, VHF or UHF analog TV has
that fading in and out rapidly from a passing aluminum cloud (airplane)
going overhead. As the plane moves, the multipath signals drive it crazy.
Computers, including digital phone magic, don't like confusing signals
fading in and out rapidly or any other way. YOU moving in a car with
multipath is why the signal comes and goes and drops your call.

It's the same physics we always had....it's the same RF radio system, no
matter what the modulation schemes put on it are....



--
Larry

"JohnF" <[email protected]> wrote in news:MlTGe.50077$5N3.36389@bgtnsc05-
news.ops.worldnet.att.net:

> AND for those who frequently travel into the boonies.
>
>
>

And ESPECIALLY for those city dwellers with the broken fanbelt 42 miles
from the city on Route 59, 8 miles from the nearest farmhouse with a
landline.....it benefits them, too!

--
Larry

Larry wrote:
> "Quick" <[email protected]> wrote in
> news:[email protected]:
>
>> Timing. Propagation delay over that distance gets too
>> large.
>>
>> -Quick
>>
>>
>
> The other problem, on land, is the multipath delays, the
> same physics that causes terrible "ghosts" on UHF TV at
> any distance without a very directional antenna, i.e.
> your little cellphone antennas. Data transmissions, even
> these really slow ones, is torn apart when the direct
> signal and another signal that has bounced off a building
> or mountain or AIRPLANE OVERHEAD comes in later than the
> main signal.
>
> When multipath occurs on FM, whether it's FM radio or FM
> 2-way or AMPS, you'll hear the multipath cause the analog
> FM signal to fade in and out in the fringe areas as the
> long path signal reinforces, then a little later opposes
> the main signal. Your FM broadcast radio, VHF or UHF
> analog TV has that fading in and out rapidly from a
> passing aluminum cloud (airplane) going overhead. As the
> plane moves, the multipath signals drive it crazy.
> Computers, including digital phone magic, don't like
> confusing signals fading in and out rapidly or any other
> way. YOU moving in a car with multipath is why the
> signal comes and goes and drops your call.
>
> It's the same physics we always had....it's the same RF
> radio system, no matter what the modulation schemes put
> on it are....

I'm not sure, but doesn't CDMA deal really well with multipath?

-Quick

"Quick" <[email protected]> wrote in message
news:[email protected]...
> Donald Newcomb wrote:
> > "DevilsPGD" <[email protected]> wrote in message
> > news:[email protected]...
> >> The ~35KM limit applies to all TDMA-based technologies,
> >> including what is commonly known as "TDMA" in Canada and
> >> the US, as well as GSM and iDEN.
> >
> > Why?
>
> Timing. Propagation delay over that distance gets too large.

Well, I've seen an exact expalnation of how this works with GSM's TDMA air
interface; number of slots, number of timing advance steps available, length
of each step in nS and meters, etc. I have not seen any such explanation for
TDMA or iDEN. It would very much surprise me if the math worked out the same
for all three.

--
Donald Newcomb
DRNewcomb (at) attglobal (dot) net

"Bob Scheurle" <[email protected]> wrote in message
news:[email protected]...
> I believe the maximum range for CDMA is about 35 miles.

Any reason why? I can't think of one.

--
Donald Newcomb
DRNewcomb (at) attglobal (dot) net

On Sun, 31 Jul 2005 03:59:00 GMT, Quick wrote:

> I'm not sure, but doesn't CDMA deal really well with multipath?

Much better than TDMA or GSM, since CDMA can use data packets from more than
one tower during a conversation. If one tower fades another one fills in.

TDMA/GSM use only one tower at a time, handing off when needed.

On Sat, 30 Jul 2005 16:34:40 GMT, Bob Scheurle wrote:

> I believe the maximum range for CDMA is about 35 miles.

CDMA's range is limited only by the signal strength between the phone and
the closest tower. Some users have reported ranges over 50 miles.

[POSTED TO alt.cellular.cingular - REPLY ON USENET PLEASE]

In <[email protected]> on Fri, 29 Jul 2005 20:54:09 -0500, "Donald
Newcomb" <[email protected]> wrote:

>"danny burstein" <[email protected]> wrote in message
>news:[email protected]...
>> In <[email protected]> "Donald Newcomb"
><[email protected]> writes:
>> Mostly, but not completely correct... While a better antenna [a] and
>> a bit mor epower are the key issues, there's also a physical
>> distance limit due to timing slot concerns.
>>
>> I don't recall the exact numbers, but 20 km as a maximum range
>> comes to mind.
>
>35 km for regular vanilla GSM. Extended range is available (at a cost). No
>limit I know of for CDMA or TDMA.

Range is roughly comparable for all three flavors.

--
Best regards, HELP FOR CINGULAR GSM & SONY ERICSSON PHONES:
John Navas <http://navasgrp.home.att.net/#Cingular>

[POSTED TO alt.cellular.cingular - REPLY ON USENET PLEASE]

In <[email protected]> on Sun, 31 Jul 2005 14:23:19
GMT, CellGuy <[email protected]> wrote:

>On Sun, 31 Jul 2005 03:59:00 GMT, Quick wrote:
>
>> I'm not sure, but doesn't CDMA deal really well with multipath?
>
>Much better than TDMA or GSM, since CDMA can use data packets from more than
>one tower during a conversation. If one tower fades another one fills in.

It doesn't really work that way, and is still subject to the same kinds of
signal issues as TDMA (including the GSM variation of TDMA).

>TDMA/GSM use only one tower at a time, handing off when needed.

True, which has pros and cons, just as CDMA has pros and cons.

--
Best regards, HELP FOR CINGULAR GSM & SONY ERICSSON PHONES:
John Navas <http://navasgrp.home.att.net/#Cingular>

[POSTED TO alt.cellular.cingular - REPLY ON USENET PLEASE]

In <[email protected]> on Sat, 30 Jul 2005 21:56:15 -0400,
Larry <[email protected]> wrote:

>"Quick" <[email protected]> wrote in
>news:[email protected]:
>
>> Timing. Propagation delay over that distance gets too large.
>
>The other problem, on land, is the multipath delays, ...

Nonsense.

--
Best regards, HELP FOR CINGULAR GSM & SONY ERICSSON PHONES:
John Navas <http://navasgrp.home.att.net/#Cingular>

[POSTED TO alt.cellular.cingular - REPLY ON USENET PLEASE]

In <[email protected]> on Sat, 30 Jul 2005 13:54:02
-0500, DevilsPGD <[email protected]> wrote:

>In message <[email protected]> "Donald Newcomb"
><[email protected]> wrote:
>
>>"danny burstein" <[email protected]> wrote in message
>>news:[email protected]...
>>> In <[email protected]> "Donald Newcomb"
>><[email protected]> writes:
>>> Mostly, but not completely correct... While a better antenna [a] and
>>> a bit mor epower are the key issues, there's also a physical
>>> distance limit due to timing slot concerns.
>>>
>>> I don't recall the exact numbers, but 20 km as a maximum range
>>> comes to mind.
>>
>>35 km for regular vanilla GSM. Extended range is available (at a cost). No
>>limit I know of for CDMA or TDMA.
>
>The ~35KM limit applies to all TDMA-based technologies, including what
>is commonly known as "TDMA" in Canada and the US, as well as GSM and
>iDEN.

The 35 km limit is based on the timing of GSM, which is one of the things that
make it more efficient than other TDMA-based technologies, like IS-136 and
iDEN, which do not have a maximum range based on timing. With maximum 3 watt
power output (and suitable terrain), iDEN can work over a distance of 50 miles
(80 km).

--
Best regards, HELP FOR CINGULAR GSM & SONY ERICSSON PHONES:
John Navas <http://navasgrp.home.att.net/#Cingular>

[POSTED TO alt.cellular.cingular - REPLY ON USENET PLEASE]

In <[email protected]> on Sat, 30 Jul 2005 21:50:31 -0400,
Larry <[email protected]> wrote:

>I sail on a French-made Amel Sharki 41' ketch along the southeast coast of
>USA. I have a Decibel Products 800 Mhz, 11 element yagi that's end-
>mounted, made for 800 Mhz paging relay service from a paging friend. It's
>very broadbanded at this band. SWR is 1.15:1 across cellular after a
>little tuning of the gamma match on it.
>
>When I had Verizon's AMPS online, hooked to a 3W Motorola bagphone running
>off ship's 12VDC house batteries, service was near perfect with the beam
>hauled up the mast and pointed towards shore at 55' for about 45-50 miles
>offshore.

The critical issue there is height above the water. Otherwise the signal
would be blocked by the curvature of the earth. It's why lighthouses need to
be tall.

>Every offshore sailor should be carrying a 99 cent thrift store
>bagphone, even if they won't let you put it on the air! With the little
>beam, it works farther than VHF marine usually does and can dial 911 by
>law. Our boat has one that's not provisioned for emergency comms...another
>backup.

EPIRB makes much more sense.

--
Best regards, HELP FOR CINGULAR GSM & SONY ERICSSON PHONES:
John Navas <http://navasgrp.home.att.net/#Cingular>

[POSTED TO alt.cellular.cingular - REPLY ON USENET PLEASE]

In <[email protected]> on Sun, 31 Jul 2005 14:26:54
GMT, CellGuy <[email protected]> wrote:

>On Sat, 30 Jul 2005 16:34:40 GMT, Bob Scheurle wrote:
>
>> I believe the maximum range for CDMA is about 35 miles.
>
>CDMA's range is limited only by the signal strength between the phone and
>the closest tower. Some users have reported ranges over 50 miles.

Likewise IS-136 and iDEN (both TDMA). Only standard GSM (also TDMA) has a
timing imposed maximum range (of 35 km, not miles).

--
Best regards, HELP FOR CINGULAR GSM & SONY ERICSSON PHONES:
John Navas <http://navasgrp.home.att.net/#Cingular>

Notan wrote:
> Isaiah Beard wrote:

>>You're *already* subsidizing phone service for the boonies. Have you
>>paid your cell phone or landline bill lately?
>
>
> And we folks, in the boonies, thank you for your support. <g>

No problem! I like to know I'll have some form of service when I vist
the boonies.

--
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Transpose the c's and a's in my e-mail address to reply.