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

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:

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)

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

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

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
--

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

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