Signal Strength - Competing Cells - Constructive/Destructive Interference

I am trying to understand why I get such a variable signal (1 tower -
5 towers - 1 tower in the same 1-2 minutes) and so many dropped calls
on my LG VX3200. I'm otherwise very satisfied with the performance of
the phone and just purchased an extended battery for mine and my
wife's to extend their working lifetime.

Yesterday I did a bit of experimentation and walked through the
neighborhood. I saw 5 tower signal strength everywhere I checked. I
walked across the street to the end of my driveway and the signal
plummeted to 1 tower and began to fluctuate. This is 20' from the
nearest part of the house.

As I stood there I thought about how the signal can be seen as
wavelike. There must be points near the border between two cell towers
where the competing signals engage in constructive and destructive
interference. Verizon can claim that they have the space covered with
a strong signal (which I saw as I walked through the neighborhood) but
I can experience the drifting of signal strength as a result of 2
competing cells.

Does this analysis make sense?

If the phone can measure signal strength, it would seem as though it
would be easy to construct a device which measures signal strength and
stores it on a flash memory card for download to Excel. Are such
devices made? It would seem that it would be in Verizon's interest to
be able to loan such a device to a subscriber to place at various
points in the service area to gather data on the quality of the
signal.

Any comments?

Thanks,

baumgrenze

If they had such a device, then the can you hear me now guy would lose
his job.


baumgrenze wrote:
> I am trying to understand why I get such a variable signal (1 tower -
> 5 towers - 1 tower in the same 1-2 minutes) and so many dropped calls
> on my LG VX3200. I'm otherwise very satisfied with the performance of
> the phone and just purchased an extended battery for mine and my
> wife's to extend their working lifetime.
>
> Yesterday I did a bit of experimentation and walked through the
> neighborhood. I saw 5 tower signal strength everywhere I checked. I
> walked across the street to the end of my driveway and the signal
> plummeted to 1 tower and began to fluctuate. This is 20' from the
> nearest part of the house.
>
> As I stood there I thought about how the signal can be seen as
> wavelike. There must be points near the border between two cell towers
> where the competing signals engage in constructive and destructive
> interference. Verizon can claim that they have the space covered with
> a strong signal (which I saw as I walked through the neighborhood) but
> I can experience the drifting of signal strength as a result of 2
> competing cells.
>
> Does this analysis make sense?
>
> If the phone can measure signal strength, it would seem as though it
> would be easy to construct a device which measures signal strength and
> stores it on a flash memory card for download to Excel. Are such
> devices made? It would seem that it would be in Verizon's interest to
> be able to loan such a device to a subscriber to place at various
> points in the service area to gather data on the quality of the
> signal.
>
> Any comments?
>
> Thanks,
>
> baumgrenze
>

"baumgrenze" <baumgrenze@yahoo.com> wrote in message news:1173721684.313523.157830@j27g2000cwj.googlegr oups.com...
>I am trying to understand why I get such a variable signal (1 tower -
> 5 towers - 1 tower in the same 1-2 minutes) and so many dropped calls
> on my LG VX3200. I'm otherwise very satisfied with the performance of
> the phone and just purchased an extended battery for mine and my
> wife's to extend their working lifetime.
>
> Yesterday I did a bit of experimentation and walked through the
> neighborhood. I saw 5 tower signal strength everywhere I checked. I
> walked across the street to the end of my driveway and the signal
> plummeted to 1 tower and began to fluctuate. This is 20' from the
> nearest part of the house.
>
> As I stood there I thought about how the signal can be seen as
> wavelike. There must be points near the border between two cell towers
> where the competing signals engage in constructive and destructive
> interference. Verizon can claim that they have the space covered with
> a strong signal (which I saw as I walked through the neighborhood) but
> I can experience the drifting of signal strength as a result of 2
> competing cells.
>
> Does this analysis make sense?
>
> If the phone can measure signal strength, it would seem as though it
> would be easy to construct a device which measures signal strength and
> stores it on a flash memory card for download to Excel. Are such
> devices made? It would seem that it would be in Verizon's interest to
> be able to loan such a device to a subscriber to place at various
> points in the service area to gather data on the quality of the
> signal.
>
> Any comments?
>
> Thanks,
>
> baumgrenze
>

First, I was amazed that you had signal problems with 5 *towers*.
It's a little unusual to be served simultaneously by five cell towers.
Later, I realized you meant *bars* of signal strength on your display.
Possibly you are getting services from a single cell tower.

Next, forget about the destructive interference idea.
That's a discrete-frequency phenomenon caused by multi-path propagation.
CDMA is a wide-spectrum signal, and multi-path signals do not kill it.
Even better, your handset uses multiple correlators in a "Rake Receiver"
which has the effect of receiving multi-path signals separately,
and combining them so as to actually *improve* reception, not degrade it.

Finally, locate the actual cell tower(s) serving your area,
and check for possible shadowing of the area where you lose signal.
Perversely, some of the shadowed areas can be filled in by signals
reflected from houses and buildings, so some places which seem ought
to be in shadow, may in fact have useful coverage by reflections.

And one added item about the handset's display of bars.
Some handsets possibly still show the signal strength per se,
but there's been a trend toward showing signal-to-noise ratio instead.
If your LG shows S/N ratio, then you'd see fewer bars in high-noise areas,
even if the actual signal *strength* remained constant.

Finding the keyboard operational
baumgrenze entered:

>
> If the phone can measure signal strength, it would seem as though it
> would be easy to construct a device which measures signal strength and
> stores it on a flash memory card for download to Excel. Are such
> devices made? It would seem that it would be in Verizon's interest to
> be able to loan such a device to a subscriber to place at various
> points in the service area to gather data on the quality of the
> signal.
>
> Any comments?
>
> Thanks,
>
> baumgrenze

You seem to want my old job of driving around testing antenna patterns,
handoff boundries, etc. It's mind numbingly boring and you can get tons of
data that may or may not be useful.
You should be able to put your phone into a diagnostic mode to see the
signal strength or even better the Ec/Io and map a small area yourself. The
commercial equipment to do this is >$10k. Also you will be able to tell what
cells you are seeing.
Bob (who will not drive thru Chicago at rush hour one more time)

--�
--�
Coffee worth staying up for - NY Times
www.moondoggiecoffee.com

"baumgrenze" <baumgrenze@yahoo.com> wrote in
news:1173721684.313523.157830@j27g2000cwj.googlegr oups.com:

> Yesterday I did a bit of experimentation and walked through the
> neighborhood. I saw 5 tower signal strength everywhere I checked. I
> walked across the street to the end of my driveway and the signal
> plummeted to 1 tower and began to fluctuate. This is 20' from the
> nearest part of the house.
>
>

I'll take the heat from the CDMA lovers, but I'll say it anyways.....

Have you ever watched analog UHF TV on a portable TV off the little loop
antenna (not the cable, of course)? Did you move around in the room, or
move the TV around, or experience what happens when an aluminum reflector
cloud (airliner) flies overhead? What happened?

Older TV viewers called it "ghosts" because the picture is scanned like
English reads, 525 horizontal lines scanned 30 frames per second from top
to bottom, skipping every other line (which is called interlacing) to
reduce flicker. TV pictures, and your computer screen you're reading
now, is an optical illusion caused by a scanning single beam lighting up
very slow decaying phosphors, but that's another story. The important
part is you saw the main picture, then you saw the "ghosts" off to the
RIGHT of the main picture, one or many of them. The reason they are to
the right is because they arrived LATER than the main picture. This
effect on RF transmission, which, dispite what digital lovers would have
you believe, is still RF transmission, is what your toyphone operates
from. RF is all ANALOG, even though the signal it's passing has been
digitized into 1's and 0's. You can't transmit 1's and 0's, you have to
modulate it on an analog RF carrier. Cellphones use FM modulation, which
isn't really important to seeing this effect.

When you are close to the TV transmitter, the main signal from it is
HUGE. We MADE it HUGE on purpose to try to reduce the ghosts, and allow
you to buy a cheap piece of crap for a receiver with lots of profit
margins. AS distance from the transmitter increases, the main signal
drops off quite rapidly as things get in the way, buildings, bridges,
towers, trees (pine needles just absorb UHF, including cellular signals).
The signal is bouncing all over the place off every piece of metal
anything you can imagine...metal framework of buildings and bridges and
other towers sticking up into the signal path, even though we mounted the
transmit antenna way high up to try to look over them.

Ok, so we have the main DIRECT signal coming straight at you as powerful
as it is (5 bars) on the north side of Elm Street, shooting over the
trees/houses/hill behind the houses. On this side of the street, with
such a strong signal, the reflections off the Main Street Bridge, WXXZ-
FM's 500 tower 2 miles away and the metal framework of the apartment
house down the street is minimal, compared to the great signal you're
getting on the north side of Elm Street. Your connections are great!

However on the OTHER side of Elm Street, the straight shot to the cell
tower (or KMMM-TV, Channel 52 on UHF) is through some trees behind the
houses, the houses themselves and gets bounced around by all the house
wiring that interrupts your DIRECT path. In relation to the signal
reflecting off the Main STreet Bridge and WXXZ-FM (Z99, "The Big Rapper")
tower...the direct signal is much less than it was across the street.
NOW, the relationships between the weaker direct signal and the REFLECTED
signals that have a longer path length arriving LATE interfere with each
other. The TV has awful ghosts on it. AS you move with the cellphone
stuck to your ear, the signal-to-reflection strength fades in and out.
CDMA (to keep the digital boys happy) has error correction schemes and
frequency hopping (which slightly changes the path length, called
"frequency diversity multiplexing". This, however, is simply overrun, at
some point, as the reflected multipath signals become crazy. On the old
FM AMPS phones, just as with the effect on an FM radio or walkie talkie,
you hear the signal fade from fully perfect to way down in the noise
level. We used to move the phone around to a "hotspot" where the signal
we could hear was best. This point is where the reflected signal is IN
PHASE with the direct signal, aiding each other around those damned
houses. On digital, your signal is so delayed by the demodulating,
decoding, synchronizing, decompressing, you don't hear any fading until
the error correction schemes are overrun and the call was dumped as being
unservicable.

In other radio systems, like wireless microphones at a rock concert,
multiple antennas are used to receive the mic signal SPACED multiples of
1/4 wavelength at their frequency from each other, sticking out two sides
of the mic receiver. This is another method of dealing with multipath
called SPACE diversity. NASA uses it to hear Mars satellites, except
their spacing is from one side of the planet to the other, thousands of
miles apart. You can see space diversity antenna arrays on wireless
internet routers sold in any store. They have 2 or 3 or 4 or more
antennas spaced around the box. A computer circuit called a "voter",
figures out which antenna has the best signal from your laptop,
CONTINUOUSLY, and switches antennas to the best one for the signal.
Multipath just eats the digital signals on 2400 Mhz 802.11x wifi
something awful because there is no POWERful transmitter. Watch the wifi
signal meter as you move a metal cookie sheet around your computer room.
It makes it go crazy.

We have exacerbated this problem squeezing more and more revenue makers
into smaller and smaller cellular towers. Everyone is running (except
me, of course) so low power, like .15 watts max, that a receiver next
door would see 20 multipath signals from your toyphone. We bagphone boys
run POWER for a reason...(c;...though many of them don't know why.


Larry
--
POWER is our friend....a kilowatt beats a milliwatt hands down on any
frequency!

"baumgrenze" <baumgrenze@yahoo.com> wrote in news:1173721684.313523.157830
@j27g2000cwj.googlegroups.com:

> It would seem that it would be in Verizon's interest to
> be able to loan such a device to a subscriber to place at various
> points in the service area to gather data on the quality of the
> signal.
>

NO WAY! That would force them to admit something was wrong! They'll never
do that. It's always your phone that's at fault. Turn it off and turn it
back on and all problems are cured...(c;

Larry
--

"John R. Copeland" <jcopelan@columbus.rr.aol.com> wrote in news:45f5b216$0
$24695$4c368faf@roadrunner.com:

> That's a discrete-frequency phenomenon caused by multi-path propagation.
>

See? Bullshit. Multipath happens on EVERY frequency it switches to. It
only switches between very-narrowly-spaced 800 or 1900 Mhz frequency
channels. It's all they have assigned.


Larry
--
How much price inflation is caused by illegal
aliens gobbling up goods and services, creating
shortages for the natives? I heard 40%!

Finding the keyboard operational
Larry entered:

> "baumgrenze" <baumgrenze@yahoo.com> wrote in
> news:1173721684.313523.157830@j27g2000cwj.googlegr oups.com:
>
>> Yesterday I did a bit of experimentation and walked through the
>> neighborhood. I saw 5 tower signal strength everywhere I checked. I
>> walked across the street to the end of my driveway and the signal
>> plummeted to 1 tower and began to fluctuate. This is 20' from the
>> nearest part of the house.
>>
>>
>
> I'll take the heat from the CDMA lovers, but I'll say it anyways.....
>
< snip of a great description of what multipath is but ignores how CDMA
receivers work>
Larry, go look up what a rake receiver is and get back to us. Until then
pplease don't post incorrect and incomplete information.
Just to help you out, yes the RF is analog but the beauty is in the digital
domain.
Bob
--�
--�
Coffee worth staying up for - NY Times
www.moondoggiecoffee.com

"The Other Funk" <bobbie@moondoggie.com> wrote in
news:cFlJh.2010$vV3.71@trndny09:

> Just to help you out, yes the RF is analog but the beauty is in the
> digital domain.
>

Then his signal, no matter how much multipath he encounters...would be
perfect.

It isn't.......bullshit.

Larry
--
How much price inflation is caused by illegal
aliens gobbling up goods and services, creating
shortages for the natives? I heard 40%!

Finding the keyboard operational
Larry entered:

> "The Other Funk" <bobbie@moondoggie.com> wrote in
> news:cFlJh.2010$vV3.71@trndny09:
>
>> Just to help you out, yes the RF is analog but the beauty is in the
>> digital domain.
>>
>
> Then his signal, no matter how much multipath he encounters...would be
> perfect.
>
> It isn't.......bullshit.
>
> Larry

Did you look at how a rake receiver works? No one ever said that the
received signal was perfect. You introduced that strawman.
Look at it this way. Say you have a group of very directional antennae. You
aim one at the direct path and others at the direction the multipath signal
comes from. Then by adjusting for the time delays, you sum all those
signals. Wouldn't you have a greater signal then from just one path?
Bob

--�
--�
Coffee worth staying up for - NY Times
www.moondoggiecoffee.com

And, Larry demonstrates a COMPLETE LACK of understanding CDMA.

I have covered rake receivers here multiple times before.

Larry either just doesn't get it or does and is simply being obtuse.

But, the FACTS are as stated by John.

100% accurate.

Larry???? 100% WRONG!!

Oh, as an added bonus, CDMA phones are capable of using multiple towers
at the same, as well as benefiting from multipath.


"Larry" <noone@home.com> wrote in message news:Xns98F1C5A1EE55Bnoonehomecom@208.49.80.253...
> "John R. Copeland" <jcopelan@columbus.rr.aol.com> wrote in news:45f5b216$0
> $24695$4c368faf@roadrunner.com:
>
>> That's a discrete-frequency phenomenon caused by multi-path propagation.
>>
>
> See? Bullshit. Multipath happens on EVERY frequency it switches to. It
> only switches between very-narrowly-spaced 800 or 1900 Mhz frequency
> channels. It's all they have assigned.
>
>
> Larry
> --
> How much price inflation is caused by illegal
> aliens gobbling up goods and services, creating
> shortages for the natives? I heard 40%!
>

It has NOTHING to do with "CDMA lovers"
I and others actually understand CDMA and how it works.
Sorry Larry, the below is correct in the analog RF world.

With CDMA, it sinply ain't as you say below.

You are 100% WRONG!!!!!!!

A rake receiver is a radio receiver designed to counter the effects of multipath fading. It does this by using several
"sub-receivers" each delayed slightly in order to tune in to the individual multipath components. Each component is
decoded independently, but at a later stage combined in order to make the most use of the different transmission
characteristics of each transmission path. This could very well result in higher signal-to-noise ratio (or Eb/N0) in a
multipath environment than in a "clean" environment.

In a RAKE receiver, one RAKE finger is assigned to each multipath, thus maximizing the amount of received signal energy.
Each of these different paths are combined to form a composite signal that is expected to have substantially better
characteristics for the purpose of demodulation than just the a single path.

The rake receiver is designed to optimally detected a CDMA signal transmitted over a dispersive multipath channel. It is
an extension of the concept of the matched filter. In a multipath channel, delayed reflections interfere with the direct
signal. However, a CDMA signal suffering from multipath dispersion can be detected by a rake receiver. This receiver
optimally combines signals received over multiple paths.


Do I need to continue??????



"Larry" <noone@home.com> wrote in message news:Xns98F1C509FA828noonehomecom@208.49.80.253...
> "baumgrenze" <baumgrenze@yahoo.com> wrote in
> news:1173721684.313523.157830@j27g2000cwj.googlegr oups.com:
>
>> Yesterday I did a bit of experimentation and walked through the
>> neighborhood. I saw 5 tower signal strength everywhere I checked. I
>> walked across the street to the end of my driveway and the signal
>> plummeted to 1 tower and began to fluctuate. This is 20' from the
>> nearest part of the house.
>>
>>
>
> I'll take the heat from the CDMA lovers, but I'll say it anyways.....
>
> Have you ever watched analog UHF TV on a portable TV off the little loop
> antenna (not the cable, of course)? Did you move around in the room, or
> move the TV around, or experience what happens when an aluminum reflector
> cloud (airliner) flies overhead? What happened?
>
> Older TV viewers called it "ghosts" because the picture is scanned like
> English reads, 525 horizontal lines scanned 30 frames per second from top
> to bottom, skipping every other line (which is called interlacing) to
> reduce flicker. TV pictures, and your computer screen you're reading
> now, is an optical illusion caused by a scanning single beam lighting up
> very slow decaying phosphors, but that's another story. The important
> part is you saw the main picture, then you saw the "ghosts" off to the
> RIGHT of the main picture, one or many of them. The reason they are to
> the right is because they arrived LATER than the main picture. This
> effect on RF transmission, which, dispite what digital lovers would have
> you believe, is still RF transmission, is what your toyphone operates
> from. RF is all ANALOG, even though the signal it's passing has been
> digitized into 1's and 0's. You can't transmit 1's and 0's, you have to
> modulate it on an analog RF carrier. Cellphones use FM modulation, which
> isn't really important to seeing this effect.
>
> When you are close to the TV transmitter, the main signal from it is
> HUGE. We MADE it HUGE on purpose to try to reduce the ghosts, and allow
> you to buy a cheap piece of crap for a receiver with lots of profit
> margins. AS distance from the transmitter increases, the main signal
> drops off quite rapidly as things get in the way, buildings, bridges,
> towers, trees (pine needles just absorb UHF, including cellular signals).
> The signal is bouncing all over the place off every piece of metal
> anything you can imagine...metal framework of buildings and bridges and
> other towers sticking up into the signal path, even though we mounted the
> transmit antenna way high up to try to look over them.
>
> Ok, so we have the main DIRECT signal coming straight at you as powerful
> as it is (5 bars) on the north side of Elm Street, shooting over the
> trees/houses/hill behind the houses. On this side of the street, with
> such a strong signal, the reflections off the Main Street Bridge, WXXZ-
> FM's 500 tower 2 miles away and the metal framework of the apartment
> house down the street is minimal, compared to the great signal you're
> getting on the north side of Elm Street. Your connections are great!
>
> However on the OTHER side of Elm Street, the straight shot to the cell
> tower (or KMMM-TV, Channel 52 on UHF) is through some trees behind the
> houses, the houses themselves and gets bounced around by all the house
> wiring that interrupts your DIRECT path. In relation to the signal
> reflecting off the Main STreet Bridge and WXXZ-FM (Z99, "The Big Rapper")
> tower...the direct signal is much less than it was across the street.
> NOW, the relationships between the weaker direct signal and the REFLECTED
> signals that have a longer path length arriving LATE interfere with each
> other. The TV has awful ghosts on it. AS you move with the cellphone
> stuck to your ear, the signal-to-reflection strength fades in and out.
> CDMA (to keep the digital boys happy) has error correction schemes and
> frequency hopping (which slightly changes the path length, called
> "frequency diversity multiplexing". This, however, is simply overrun, at
> some point, as the reflected multipath signals become crazy. On the old
> FM AMPS phones, just as with the effect on an FM radio or walkie talkie,
> you hear the signal fade from fully perfect to way down in the noise
> level. We used to move the phone around to a "hotspot" where the signal
> we could hear was best. This point is where the reflected signal is IN
> PHASE with the direct signal, aiding each other around those damned
> houses. On digital, your signal is so delayed by the demodulating,
> decoding, synchronizing, decompressing, you don't hear any fading until
> the error correction schemes are overrun and the call was dumped as being
> unservicable.
>
> In other radio systems, like wireless microphones at a rock concert,
> multiple antennas are used to receive the mic signal SPACED multiples of
> 1/4 wavelength at their frequency from each other, sticking out two sides
> of the mic receiver. This is another method of dealing with multipath
> called SPACE diversity. NASA uses it to hear Mars satellites, except
> their spacing is from one side of the planet to the other, thousands of
> miles apart. You can see space diversity antenna arrays on wireless
> internet routers sold in any store. They have 2 or 3 or 4 or more
> antennas spaced around the box. A computer circuit called a "voter",
> figures out which antenna has the best signal from your laptop,
> CONTINUOUSLY, and switches antennas to the best one for the signal.
> Multipath just eats the digital signals on 2400 Mhz 802.11x wifi
> something awful because there is no POWERful transmitter. Watch the wifi
> signal meter as you move a metal cookie sheet around your computer room.
> It makes it go crazy.
>
> We have exacerbated this problem squeezing more and more revenue makers
> into smaller and smaller cellular towers. Everyone is running (except
> me, of course) so low power, like .15 watts max, that a receiver next
> door would see 20 multipath signals from your toyphone. We bagphone boys
> run POWER for a reason...(c;...though many of them don't know why.
>
>
> Larry
> --
> POWER is our friend....a kilowatt beats a milliwatt hands down on any
> frequency!
>
>

On 3/12/2007 4:03 PM, John R. Copeland wrote:
> "baumgrenze" <baumgrenze@yahoo.com> wrote . . .
>> I am trying to understand why I get such a variable signal (1 tower -
>> 5 towers - 1 tower in the same 1-2 minutes) and so many dropped calls
>> on my LG VX3200. I'm otherwise very satisfied with the performance of
>> the phone and just purchased an extended battery for mine and my
>> wife's to extend their working lifetime.
[snip]
>> As I stood there I thought about how the signal can be seen as
>> wavelike. There must be points near the border between two cell towers
>> where the competing signals engage in constructive and destructive
>> interference. Verizon can claim that they have the space covered with
>> a strong signal (which I saw as I walked through the neighborhood) but
>> I can experience the drifting of signal strength as a result of 2
>> competing cells.
>>
>> Does this analysis make sense?

As John Copeland indicates below, the bars don't correspond to the
number of towers. In fact, they provide a pretty gross approximation of
the tower's signal strength. Your phone may have a diagnostic or test
mode that allows it to display the received signal strength in dBm and
identifiers of multiple towers.

If the bars did correspond to towers, and if you were receiving plain
old FM signals, yes. With CDMA, no. A CDMA network allows your phone
to receive, and transmit to, multiple cells operating on the same
channel. The network decides which tower will establish communications
with your handset, and it changes that decision as traffic demands.
This is known as "soft handoff".

>> If the phone can measure signal strength, it would seem as though it
>> would be easy to construct a device which measures signal strength and
>> stores it on a flash memory card for download to Excel. Are such
>> devices made? It would seem that it would be in Verizon's interest to
>> be able to loan such a device to a subscriber to place at various
>> points in the service area to gather data on the quality of the
>> signal.

One problem with your proposal is that the power transmitted from CDMA
towers varies continuously. Your phone may be within easy
communications range of two towers, but both towers power down because
they are carrying a large number of conversations from subscribers close
in. As a result, the phone shows only one bar and can't make a call.
Later, the same phone in the same location may show five bars and can
make calls without any problem.

> First, I was amazed that you had signal problems with 5 *towers*.
> It's a little unusual to be served simultaneously by five cell towers.
> Later, I realized you meant *bars* of signal strength on your display.
> Possibly you are getting services from a single cell tower.
>
> Next, forget about the destructive interference idea.
> That's a discrete-frequency phenomenon caused by multi-path propagation.
> CDMA is a wide-spectrum signal, and multi-path signals do not kill it.
> Even better, your handset uses multiple correlators in a "Rake Receiver"
> which has the effect of receiving multi-path signals separately,
> and combining them so as to actually *improve* reception, not degrade it.
>
> Finally, locate the actual cell tower(s) serving your area,
> and check for possible shadowing of the area where you lose signal.
> Perversely, some of the shadowed areas can be filled in by signals
> reflected from houses and buildings, so some places which seem ought
> to be in shadow, may in fact have useful coverage by reflections.
>
> And one added item about the handset's display of bars.
> Some handsets possibly still show the signal strength per se,
> but there's been a trend toward showing signal-to-noise ratio instead.
> If your LG shows S/N ratio, then you'd see fewer bars in high-noise areas,
> even if the actual signal *strength* remained constant.

Actually, in CDMA S/N ratio is pretty much irrelevant. The factor used
in determining call quality is Eb/N0. Damned if I know what it stands
for, though.

--
Michael D. Sullivan
Bethesda, MD (USA)
(To reply, change example.invalid to com in the address.)

Thank you everybody for your input.

Here are some more basic questions from a casual user of cellphone
technology.

1) How far from my point of use can a functional cell tower be?

2) Is the ability of a given tower to provide service to an individual
subscriber a function of the number of calls it it handling?

3) If so, does it attempt to pass a call or an attempt to call off to
a neighboring tower if it is a functional distance away?

4) If a subscriber finds himself midway between two towers can he
experience variable service because the phone has trouble deciding
which tower to use?

Someone suggested looking for towers and for multipath reflectors.

I am located on the flats, not far from San Francisco Bay, i.e., about
1/2 mile west of 101 and very close to the Oregon Expressway.

Verizon is not willing to say where their towers in my vicinity are
located. I know of a tower in the flagpole at the fire station at
Newell and Embarcadero (ca 0.5 miles) and another in the steeple of
the Congregational Church at Louis and Embarcadero (ca 0.4 miles.) I
don't know if Verizon uses either of them. I have not seen cell towers
elsewhere in my neighborhood.

Are providers required to register cell phone tower locations with
some public agency? Can I gain access to location information in that
way?

Should I consider installing an antenna/repeater product to improve
reception inside my house?

Thanks,

baumgrenze

Thank you everybody for your input.

Here are some more basic questions from a casual user of cellphone
technology.

1) How far from my point of use can a functional cell tower be?

2) Is the ability of a given tower to provide service to an individual
subscriber a function of the number of calls it it handling?

3) If so, does it attempt to pass a call or an attempt to call off to
a neighboring tower if it is a functional distance away?

4) If a subscriber finds himself midway between two towers can he
experience variable service because the phone has trouble deciding
which tower to use?

Someone suggested looking for towers and for multipath reflectors.

I am located on the flats, not far from San Francisco Bay, i.e., about
1/2 mile west of 101 and very close to the Oregon Expressway.

Verizon is not willing to say where their towers in my vicinity are
located. I know of a tower in the flagpole at the fire station at
Newell and Embarcadero (ca 0.5 miles) and another in the steeple of
the Congregational Church at Louis and Embarcadero (ca 0.4 miles.) I
don't know if Verizon uses either of them. I have not seen cell towers
elsewhere in my neighborhood.

Are providers required to register cell phone tower locations with
some public agency? Can I gain access to location information in that
way?

Should I consider installing an antenna/repeater product to improve
reception inside my house?

Thanks,

baumgrenze

"The Other Funk" <bobbie@moondoggie.com> wrote in
news:YpnJh.1907$Bi2.482@trnddc01:

> Did you look at how a rake receiver works? No one ever said that the
> received signal was perfect. You introduced that strawman.
> Look at it this way. Say you have a group of very directional
> antennae. You aim one at the direct path and others at the direction
> the multipath signal comes from. Then by adjusting for the time
> delays, you sum all those signals. Wouldn't you have a greater signal
> then from just one path?
>

No, you wouldn't. Air doesn't conduct RF well at all. It absorbs it.
Anything you can do to concentrate RF on the shortest possible path
increases the signal at the receiver.

You can't adjust the time delays because they are always changing and the
multipaths are always changing, especially on a cellular system where the
transmitter phone is moving very fast through the multipath minefield.

One of our greatest mistakes was putting cellular, and later PCS, so far
up the RF spectrum. It was done for a variety of reasons related to
antenna size, available spectrum space, telephone company politics trying
to prevent losing their IMTS cash cows, etc. VHF signals propagate much
better, and with lots less attenuation, than UHF. Find a TV station on
channels 2-6 and see how much better the signal is to that portable TV.
TV stations all wanted to be BELOW the FM radio band, channels 2-6 for
this reason. Cellular doesn't have this luxury. We're hogtied with 850
or 1900 Mhz, damned near in the microwave bands and very short ranged,
the reason the signal level drops so fast as you move away from the cell.

"baumgrenze" <baumgrenze@yahoo.com> wrote in
news:1173766863.784236.257220@n33g2000cwc.googlegr oups.com:

> Here are some more basic questions from a casual user of cellphone
> technology.
>
> 1) How far from my point of use can a functional cell tower be?

PCS on 1900 Mhz - 2 miles. Cellular on 850 Mhz - 3-4 miles IF YOU'RE
OUTSIDE. Range drops in hills or city canyons of steel buildings. All
cellular/PCS is line-of-sight. If you don't have a clear shot at the
tower, It ain't gonna happen. There is no over-the-hill-or-horizon on
these frequencies.
>
> 2) Is the ability of a given tower to provide service to an individual
> subscriber a function of the number of calls it it handling?

Yes. The reason for all the digital hype is many users can use the same
channel at once because the cellphone is transmitting data in bursts, as
needed, switching channels very fast to find a spot to send it called
spread spectrum. It's very fault tolerant and can correct errors...up to
a point. You hear the point as your phone starts buzzing and beeping
decoding pieces and bits of the data stream or dropping in and out.

>
> 3) If so, does it attempt to pass a call or an attempt to call off to
> a neighboring tower if it is a functional distance away?

Overloaded digital systems simply don't make the call in the first place
until it can find a space to put you. Because there are so many spaces
available, unlike the old analog systems, this rarely happens until
something catastrophic happens that creates a storm of calls, at which
point the whole system breaks down. Making a call as a hurricane
approaches Charleston, for instance, becomes catatonic.

>
> 4) If a subscriber finds himself midway between two towers can he
> experience variable service because the phone has trouble deciding
> which tower to use?
>
>

Tower spacing is an art form few cheapskate cellphone companies are good
at. The landscape of reflecting surfaces, mountains, attenuating trees
is very complex and the models used to determine any transmitter's
effective field strength are only so good. Actual experience of the
users is always less than the models because the models can't take into
account that Boeing 747 your signal is reflecting off as it climbs out of
the nearby airport or the rain or the other traffic around you. Even the
heat of the sun coming off a hot parking lot creates RF noise that raises
the noise floor and reduces range of RF devices. This is especially true
of satellite TV, etc. Noise and attenuation is your enemy.

In reality, you end up with towers that are too far apart for comfort,
for a variety of social, political and MOSTLY economic reasons. In any
locality, you'll find dead zones of poor coverage on Carrier A that
Carrier B has covered from a different place. For a time, the carriers
got together and shared resources, allowing you to roam IN MARKET when
your carrier went tits up at a location. Reality soon set in as the
roaming went bananas across the country because everyone's coverage
sucked so bad. The cure was the PRL so the company could FORCE your
phone to ignore a perfectly good signal when its allowed connections,
listed in the PRL, were too awful to use. So, you end up standing in the
shadow of a half-loaded cellphone tower with a dead or poorly working
phone that COULD be using one of those channels, solid, but is forbidden
from doing so to save your carrier a few pennies. Service from all of
them is poor in some areas because noone is forcing them to do what's
right and allow in-market roaming if they don't have smooth coverage
across their licensed areas. FCC does nothing to protect the customers
because it's in cellular's back pocket...even though cellular is using
the PUBLIC's airwaves. It doesn't have to be this way.

Back in the AMPS days, the carriers didn't control the phones. A phone
set to STD A/B (or STD B/A depending on which system you were on) would
roam over to the other guys system and make the calls. Cellular's weapon
to combat this practice was to charge you an awful roaming rate, several
dollars per minute, which kept the users' phones set to HOME ONLY, except
for the very rich and businesses that had to have service.


Larry
--

On 2007-03-13, Michael D. Sullivan <userid@camsul.example.invalid> wrote:
> On 3/12/2007 4:03 PM, John R. Copeland wrote:
>> And one added item about the handset's display of bars.
>> Some handsets possibly still show the signal strength per se,
>> but there's been a trend toward showing signal-to-noise ratio instead.
>> If your LG shows S/N ratio, then you'd see fewer bars in high-noise areas,
>> even if the actual signal *strength* remained constant.
>
> Actually, in CDMA S/N ratio is pretty much irrelevant. The factor used
> in determining call quality is Eb/N0. Damned if I know what it stands
> for, though.

The Eb is the energy per bit, i.e. the signal power. No is the spectral
density of noise, i.e. the noise power. Eb/No is essentially a fancy
way of saying signal-to-noise ratio.

Dennis Ferguson

On 2007-03-12, Larry <noone@home.com> wrote:
> "John R. Copeland" <jcopelan@columbus.rr.aol.com> wrote in news:45f5b216$0
> $24695$4c368faf@roadrunner.com:
>
>> That's a discrete-frequency phenomenon caused by multi-path propagation.
>
> See? Bullshit. Multipath happens on EVERY frequency it switches to. It
> only switches between very-narrowly-spaced 800 or 1900 Mhz frequency
> channels. It's all they have assigned.

Larry, you should know that the CDMA we use for phone service isn't
frequency-hopping spread spectrum, it is direct sequence spread spectrum.
It doesn't switch frequencies, it transmits a signal that is 1.23 MHz
wide to carry a very small bit rate.

For multipath to effect all parts of a signal that wide the same way
the difference in path lengths would have to be small compared to
250 meters, the wavelength of 1.23 MHz. With a path length difference
of 250 meters you are guaranteed that if there is a null somewhere in
the 1.23 MHz there will be a peak somewhere else, and as the difference
increases you'll get more peaks and nulls. Because of this, by far
the most common effect of multipath isn't that the whole signal goes
away but rather that the signal is distorted.

The technique mentioned to you is a time-domain method of removing
that distortion.

Dennis Ferguson

Here's another thought.

If I construct a small parabolic reflector that I can slip on to the
antenna on my cell phone, made, say, of fine mesh stainless steel,
will it allow me to sweep around in a given location to try to find
the tower that is supplying my service?

Won't this technique allow me to determine the direction of the
strongest signal, as well as to find some somewhat weaker reflections.

My guess is that I should start with 'dish' that has a diameter
similar to the length of my antenna, am I right?

Thanks,

baumgrenze

"baumgrenze" <baumgrenze@yahoo.com> wrote in message news:1173817383.309110.60780@d57g2000hsg.googlegro ups.com...
> Here's another thought.
>
> If I construct a small parabolic reflector that I can slip on to the
> antenna on my cell phone, made, say, of fine mesh stainless steel,
> will it allow me to sweep around in a given location to try to find
> the tower that is supplying my service?
>
> Won't this technique allow me to determine the direction of the
> strongest signal, as well as to find some somewhat weaker reflections.
>
> My guess is that I should start with 'dish' that has a diameter
> similar to the length of my antenna, am I right?
>
> Thanks,
>
> baumgrenze
>

No. Not even close. Dishes are many wavelengths large.
And the radiating element must be held at the parabolic focus.

Learn how to put your phone into something like diagnostic mode,
so it will display cell identification numbers.and received signal strength.
IIRC, the ID numbers are always numbers smaller than 512.
(If I got that wrong, someone here will correct me.)

When you arrive near a cell tower, the signal will be very strong,
and as you travel around the tower, you'll likely see three different
cell-number identifications, in azimuthal sectors 120-degrees wide.
Typically, sector centerlines lie north, southeast, and southwest.
Thus, your IDs may change near azimuths of 60, 180, and 300 degrees.
(That's common urban practice. Rural areas could be different.)
If you don't see different sector numbers around the tower,
then you aren't circling the right one. Keep looking.

John R. Copeland wrote:
>
> First, I was amazed that you had signal problems with 5 *towers*.
> It's a little unusual to be served simultaneously by five cell towers.
> Later, I realized you meant *bars* of signal strength on your display.
> Possibly you are getting services from a single cell tower.
>

Not if you live on top of a hill in a large city. When I lived in San
Diego I could see towers up to twenty miles away including Mexico. I
had full bars and a lot of dropped calls.

I was not quite at the top of the hill (two houses above me) and found
the best spot in the house was where the bank to the next terraced lot
above was at its closest. In that spot, calls were rarely dropped.

--
SlobbyDon

Finding the keyboard operational
Ness_net entered:

> It has NOTHING to do with "CDMA lovers"
> I and others actually understand CDMA and how it works.
> Sorry Larry, the below is correct in the analog RF world.
>
> With CDMA, it sinply ain't as you say below.
>
> You are 100% WRONG!!!!!!!
>
> A rake receiver is a radio receiver designed to counter the effects
> of multipath fading. It does this by using several "sub-receivers"
> each delayed slightly in order to tune in to the individual multipath
> components. Each component is decoded independently, but at a later
> stage combined in order to make the most use of the different
> transmission characteristics of each transmission path. This could
> very well result in higher signal-to-noise ratio (or Eb/N0) in a
> multipath environment than in a "clean" environment.
> In a RAKE receiver, one RAKE finger is assigned to each multipath,
> thus maximizing the amount of received signal energy. Each of these
> different paths are combined to form a composite signal that is
> expected to have substantially better characteristics for the purpose
> of demodulation than just the a single path.
> The rake receiver is designed to optimally detected a CDMA signal
> transmitted over a dispersive multipath channel. It is an extension
> of the concept of the matched filter. In a multipath channel, delayed
> reflections interfere with the direct signal. However, a CDMA signal
> suffering from multipath dispersion can be detected by a rake
> receiver. This receiver optimally combines signals received over
> multiple paths.
>
> Do I need to continue??????
>
Ness, don't do Larry's homework for him. Thanks for typing out what a rake
receiver is for everyone else though.
Bob ( who knows that Larry isn't going to change)

--�
--�
Coffee worth staying up for - NY Times
www.moondoggiecoffee.com

1. With CDMA distance is adjustable to help optimize the system. There is no firm distance.
So, if a cell needs to be throttled back because of multiple factors, engineers can.

2. Absolutely yes, with CDMA - called cell 'breathing'

3. That is why it's called cellular - it's the basic concept behind it. Calls are handed from cell
to cell when moving from one area to another - it called a handoff. BUT, with CDMA, your phone
can and does use multiple cells at once and handoffs are soft. (it doesn't drop one before establishing
another.

4. Not with CDMA - theoretically. But say one cell is extremely loaded and can't take the handoff. Again
with CDMA and the multiple cells at once, this is usually not a factor.

The thing to remember about CDMA is something called noise floor. Very simply, every thing else out there,
(other calls on the system at the same time) are seen as noise. As long as the phone can pull your call
out of the noise, you have a call. When that noise reaches a certain level, bye bye.

I'll leave the rest for someone else.



"baumgrenze" <baumgrenze@yahoo.com> wrote in message news:1173769542.190525.137770@t69g2000cwt.googlegr oups.com...
> Thank you everybody for your input.
>
> Here are some more basic questions from a casual user of cellphone
> technology.
>
> 1) How far from my point of use can a functional cell tower be?
>
> 2) Is the ability of a given tower to provide service to an individual
> subscriber a function of the number of calls it it handling?
>
> 3) If so, does it attempt to pass a call or an attempt to call off to
> a neighboring tower if it is a functional distance away?
>
> 4) If a subscriber finds himself midway between two towers can he
> experience variable service because the phone has trouble deciding
> which tower to use?
>
> Someone suggested looking for towers and for multipath reflectors.
>
> I am located on the flats, not far from San Francisco Bay, i.e., about
> 1/2 mile west of 101 and very close to the Oregon Expressway.
>
> Verizon is not willing to say where their towers in my vicinity are
> located. I know of a tower in the flagpole at the fire station at
> Newell and Embarcadero (ca 0.5 miles) and another in the steeple of
> the Congregational Church at Louis and Embarcadero (ca 0.4 miles.) I
> don't know if Verizon uses either of them. I have not seen cell towers
> elsewhere in my neighborhood.
>
> Are providers required to register cell phone tower locations with
> some public agency? Can I gain access to location information in that
> way?
>
> Should I consider installing an antenna/repeater product to improve
> reception inside my house?
>
> Thanks,
>
> baumgrenze
>
>
>

Sorry but I have to reply inline too.
Finding the keyboard operational
Larry entered:

> "baumgrenze" <baumgrenze@yahoo.com> wrote in
> news:1173766863.784236.257220@n33g2000cwc.googlegr oups.com:
>
>> Here are some more basic questions from a casual user of cellphone
>> technology.
>>
>> 1) How far from my point of use can a functional cell tower be?
>
> PCS on 1900 Mhz - 2 miles. Cellular on 850 Mhz - 3-4 miles IF YOU'RE
> OUTSIDE. Range drops in hills or city canyons of steel buildings.
> All cellular/PCS is line-of-sight. If you don't have a clear shot at
> the tower, It ain't gonna happen. There is no
> over-the-hill-or-horizon on these frequencies.

This is pretty much correct.

>>
>> 2) Is the ability of a given tower to provide service to an
>> individual subscriber a function of the number of calls it it
>> handling?
>
> Yes. The reason for all the digital hype is many users can use the
> same channel at once because the cellphone is transmitting data in
> bursts, as needed, switching channels very fast to find a spot to
> send it called spread spectrum. It's very fault tolerant and can
> correct errors...up to a point. You hear the point as your phone
> starts buzzing and beeping decoding pieces and bits of the data
> stream or dropping in and out.
>
Larry gets partial credit because he word "yes" is correct but the rest of
his explanation demonstrates that he has no idea what he is talking about.
It seems like he is thinking TDMA.
If a cell is at it's maximum users you will not be able to place a call or
your call will not be able to handoff. How rare this is depends greatly on
where you are and how much work the provider put into network design. There
is also a condition known as "cell breathing" where a highly loaded cell
will drop calls at it's fringe.
>>
>> 3) If so, does it attempt to pass a call or an attempt to call off to
>> a neighboring tower if it is a functional distance away?
>
> Overloaded digital systems simply don't make the call in the first
> place until it can find a space to put you. Because there are so
> many spaces available, unlike the old analog systems, this rarely
> happens until something catastrophic happens that creates a storm of
> calls, at which point the whole system breaks down. Making a call as
> a hurricane approaches Charleston, for instance, becomes catatonic.
>
The system should make every attempt to connect you call and to keep it
connected but it's nowhere near perfect. Your preception is that you don't
notice the switching between cells, the soft and softer handoffs. You do
notice the call dropping right away.

>>
>> 4) If a subscriber finds himself midway between two towers can he
>> experience variable service because the phone has trouble deciding
>> which tower to use?
>>
>>
>
> Tower spacing is an art form few cheapskate cellphone companies are
> good at. The landscape of reflecting surfaces, mountains,
> attenuating trees is very complex and the models used to determine
> any transmitter's effective field strength are only so good. Actual
> experience of the users is always less than the models because the
> models can't take into account that Boeing 747 your signal is
> reflecting off as it climbs out of the nearby airport or the rain or
> the other traffic around you. Even the heat of the sun coming off a
> hot parking lot creates RF noise that raises the noise floor and
> reduces range of RF devices. This is especially true of satellite
> TV, etc. Noise and attenuation is your enemy.
>
Larry has no clue as too what models are used or how complex they are. The
only parts that he has correct are "Noise and attenuation is your enemy. "

> In reality, you end up with towers that are too far apart for comfort,
> for a variety of social, political and MOSTLY economic reasons. In
> any locality, you'll find dead zones of poor coverage on Carrier A
> that Carrier B has covered from a different place. For a time, the
> carriers got together and shared resources, allowing you to roam IN
> MARKET when your carrier went tits up at a location. Reality soon
> set in as the roaming went bananas across the country because
> everyone's coverage sucked so bad. The cure was the PRL so the
> company could FORCE your phone to ignore a perfectly good signal when
> its allowed connections, listed in the PRL, were too awful to use.
> So, you end up standing in the shadow of a half-loaded cellphone
> tower with a dead or poorly working phone that COULD be using one of
> those channels, solid, but is forbidden from doing so to save your
> carrier a few pennies. Service from all of them is poor in some
> areas because noone is forcing them to do what's right and allow
> in-market roaming if they don't have smooth coverage across their
> licensed areas. FCC does nothing to protect the customers because
> it's in cellular's back pocket...even though cellular is using the
> PUBLIC's airwaves. It doesn't have to be this way.

This is Larry's political rant that has a minimum basis in truth.

Baumgrenze, if 2 people here give you the same info, it's probably the right
stuff. If it's only 1 person, be wary.
Bob
--�
--�
Coffee worth staying up for - NY Times
www.moondoggiecoffee.com

And don't listen to Larry.....
Full of misinformation, or lack of understanding.
Which the below is.

Example: TDMA is "bursts" (not CDMA)



"Larry" <noone@home.com> wrote in message news:Xns98F25D5D5853Dnoonehomecom@208.49.80.253...
> "baumgrenze" <baumgrenze@yahoo.com> wrote in
> news:1173766863.784236.257220@n33g2000cwc.googlegr oups.com:
>
>> Here are some more basic questions from a casual user of cellphone
>> technology.
>>
>> 1) How far from my point of use can a functional cell tower be?
>
> PCS on 1900 Mhz - 2 miles. Cellular on 850 Mhz - 3-4 miles IF YOU'RE
> OUTSIDE. Range drops in hills or city canyons of steel buildings. All
> cellular/PCS is line-of-sight. If you don't have a clear shot at the
> tower, It ain't gonna happen. There is no over-the-hill-or-horizon on
> these frequencies.
>>
>> 2) Is the ability of a given tower to provide service to an individual
>> subscriber a function of the number of calls it it handling?
>
> Yes. The reason for all the digital hype is many users can use the same
> channel at once because the cellphone is transmitting data in bursts, as
> needed, switching channels very fast to find a spot to send it called
> spread spectrum. It's very fault tolerant and can correct errors...up to
> a point. You hear the point as your phone starts buzzing and beeping
> decoding pieces and bits of the data stream or dropping in and out.
>
>>
>> 3) If so, does it attempt to pass a call or an attempt to call off to
>> a neighboring tower if it is a functional distance away?
>
> Overloaded digital systems simply don't make the call in the first place
> until it can find a space to put you. Because there are so many spaces
> available, unlike the old analog systems, this rarely happens until
> something catastrophic happens that creates a storm of calls, at which
> point the whole system breaks down. Making a call as a hurricane
> approaches Charleston, for instance, becomes catatonic.
>
>>
>> 4) If a subscriber finds himself midway between two towers can he
>> experience variable service because the phone has trouble deciding
>> which tower to use?
>>
>>
>
> Tower spacing is an art form few cheapskate cellphone companies are good
> at. The landscape of reflecting surfaces, mountains, attenuating trees
> is very complex and the models used to determine any transmitter's
> effective field strength are only so good. Actual experience of the
> users is always less than the models because the models can't take into
> account that Boeing 747 your signal is reflecting off as it climbs out of
> the nearby airport or the rain or the other traffic around you. Even the
> heat of the sun coming off a hot parking lot creates RF noise that raises
> the noise floor and reduces range of RF devices. This is especially true
> of satellite TV, etc. Noise and attenuation is your enemy.
>
> In reality, you end up with towers that are too far apart for comfort,
> for a variety of social, political and MOSTLY economic reasons. In any
> locality, you'll find dead zones of poor coverage on Carrier A that
> Carrier B has covered from a different place. For a time, the carriers
> got together and shared resources, allowing you to roam IN MARKET when
> your carrier went tits up at a location. Reality soon set in as the
> roaming went bananas across the country because everyone's coverage
> sucked so bad. The cure was the PRL so the company could FORCE your
> phone to ignore a perfectly good signal when its allowed connections,
> listed in the PRL, were too awful to use. So, you end up standing in the
> shadow of a half-loaded cellphone tower with a dead or poorly working
> phone that COULD be using one of those channels, solid, but is forbidden
> from doing so to save your carrier a few pennies. Service from all of
> them is poor in some areas because noone is forcing them to do what's
> right and allow in-market roaming if they don't have smooth coverage
> across their licensed areas. FCC does nothing to protect the customers
> because it's in cellular's back pocket...even though cellular is using
> the PUBLIC's airwaves. It doesn't have to be this way.
>
> Back in the AMPS days, the carriers didn't control the phones. A phone
> set to STD A/B (or STD B/A depending on which system you were on) would
> roam over to the other guys system and make the calls. Cellular's weapon
> to combat this practice was to charge you an awful roaming rate, several
> dollars per minute, which kept the users' phones set to HOME ONLY, except
> for the very rich and businesses that had to have service.
>
>
> Larry
> --

Finding the keyboard operational
Larry entered:

> "The Other Funk" <bobbie@moondoggie.com> wrote in
> news:YpnJh.1907$Bi2.482@trnddc01:
>
>> Did you look at how a rake receiver works? No one ever said that the
>> received signal was perfect. You introduced that strawman.
>> Look at it this way. Say you have a group of very directional
>> antennae. You aim one at the direct path and others at the direction
>> the multipath signal comes from. Then by adjusting for the time
>> delays, you sum all those signals. Wouldn't you have a greater signal
>> then from just one path?
>>
>
> No, you wouldn't. Air doesn't conduct RF well at all. It absorbs it.
> Anything you can do to concentrate RF on the shortest possible path
> increases the signal at the receiver.
>
> You can't adjust the time delays because they are always changing and
> the multipaths are always changing, especially on a cellular system
> where the transmitter phone is moving very fast through the multipath
> minefield.
>
> One of our greatest mistakes was putting cellular, and later PCS, so
> far up the RF spectrum. It was done for a variety of reasons related
> to antenna size, available spectrum space, telephone company politics
> trying to prevent losing their IMTS cash cows, etc. VHF signals
> propagate much better, and with lots less attenuation, than UHF.
> Find a TV station on channels 2-6 and see how much better the signal
> is to that portable TV. TV stations all wanted to be BELOW the FM
> radio band, channels 2-6 for this reason. Cellular doesn't have this
> luxury. We're hogtied with 850 or 1900 Mhz, damned near in the
> microwave bands and very short ranged, the reason the signal level
> drops so fast as you move away from the cell.

Larry are you really that obtuse ir are you just trying to mislead people
for fun?
Please show use some evidence that CDMA does not take advantage of multipath
signals.
Bob

--�
--�
Coffee worth staying up for - NY Times
www.moondoggiecoffee.com

On Mar 13, 3:12 pm, "John R. Copeland" <jcope...@columbus.rr.aol.com>
wrote:
> "baumgrenze" <baumgre...@yahoo.com> wrote in messagenews:1173817383.309110.60780@d57g2000hsg.go oglegroups.com...

Thanks for the advice regarding "diagnostic mode." I spent some time
trying to learn about this. I gather that Verizon won't be helpful
since it might suggest that I want to use the phone elsewhere. I
gather, too, that it is important to know how to get back out of
diagnostic mode as well as how to get in.

thanks

baumgrenze

> No. Not even close. Dishes are many wavelengths large.
> And the radiating element must be held at the parabolic focus.
>
> Learn how to put your phone into something likediagnosticmode,
> so it will display cell identification numbers.and received signal strength.
> IIRC, the ID numbers are always numbers smaller than 512.
> (If I got that wrong, someone here will correct me.)
>
> When you arrive near a cell tower, the signal will be very strong,
> and as you travel around the tower, you'll likely see three different
> cell-number identifications, in azimuthal sectors 120-degrees wide.
> Typically, sector centerlines lie north, southeast, and southwest.
> Thus, your IDs may change near azimuths of 60, 180, and 300 degrees.
> (That's common urban practice. Rural areas could be different.)
> If you don't see different sector numbers around the tower,
> then you aren't circling the right one. Keep looking.

Dennis Ferguson <dcferguson@pacbell.net> wrote in
news:slrnevdr3m.8c.dcferguson@akit-ferguson.com:

> Dennis Ferguson
>

The magic didn't work, yesterday. My new Moto M800 1/4 watt bagphone
sucked in the forest by itself. I'm returning it to Alltel today.

It's crowning glory is its wonderful speakerphone you can actually hear
as well as its ringer. But, alas, a 1/4 watt CDMA phone (actually, I'm
convinced from all its exactly similar commands, a V60i in a big box,
isn't worth the hassle of carrying this beast around and constantly
plugging it in because it's such a power hog. The audio amp must be
running class A to suck up the big battery so fast, as well as leaving
the lights on all the time. Stupid, Moto, stupid.

Back she goes, CDMA magic or no CDMA magic.

Question for you CDMA experts.....
If CDMA is such cellular magic, why is only 3 companies in the USA using
it....and the rest of the civilized world using GSM?? There's no CDMA I
know of in Europe, at all.

Maybe the Illuminati of the New World Order can set a worldwide cellular
standard so your phone works anywhere, any time, when the Freemasons take
over.

Larry
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"Ness_net" <richard@nomore.damn.spam.nessnet.com> wrote in
news:x9ydnRW4JcMg1mrYnZ2dnUVZ_uuqnZ2d@giganews.com :

> With CDMA distance is adjustable to help optimize the system.

With CDMA, distance is adjustable to help optimize the profits.

There. That's more correct.

Larry
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