MiFi purchase and contract options?

Richard B. Gilbert wrote on [Sat, 03 Jul 2010 15:38:32 -0400]:
> Justin wrote:
>> Richard B. Gilbert wrote on [Sat, 03 Jul 2010 14:40:59 -0400]:
>>> Justin wrote:
>>>> Larry wrote on [Sat, 03 Jul 2010 14:27:22 +0000]:
>>>>> Justin <[email protected]> wrote in news:[email protected]
>>>>> september.org:
>>>>>
>>>>>> data mining.
>>>>> Precisely my point about the horrors of cloud computing.....
>>>> yep, however this point had nothing to do with the cloud
>>> Who is responsible for the integrity and security of data stored "in the
>>> cloud"? Why should I, or anyone, be willing to entrust his data to it?
>>
>> That's why I encrypt the data I sent to my cloud backup service. My email
>> already travels unencrypted across less trustworthy servers than google
>> between the end user hitting send and me receiving it. I trust comcast
>> a whole bunch less than google. AT&T even less than Comcast, yet how
>> many people use one of those as their ISP?
>>
>> The cloud is not a single entity, it's Amazon, it's Google, it's Microsoft,
>> it's facebook, it's Yahoo, etc.
>> You need to pick who you want to trust and for what service. It's no different
>> than trusting your doctor with your medical records. Or perhaps which pharmacy
>> you trust when you fill your prescription.
>>
>
> Thanks!
>
> I think I will continue to backup my phone to my computer. I also have
> very similar data on my PDA if I should happen to need it. If all three
> sources are somehow destroyed I probably won't be in any condition to
> care!

That's a nice theory, but if you are at the grocery store during a storm and your
house is blown away with your computer, and you get caught in a heavy downpour and your
phone gets wet and stops working, you can still be in pretty good condition
and have lost it all.

---

› See More: MiFi purchase and contract options?

In article <[email protected]>, Jeff
Liebermann <[email protected]> wrote:

> >"More suits filed in iPhone 4 antenna fracas"
> ><http://news.cnet.com/8301-31021_3-20009625-260.html>
> At first, Apple said this was a problem common to any phone
> and suggested buying a rubber case or holding the phone
> differently.
> Translation: Apple doesn't have a clue about RF and is now in damage
> control mode. Blaming the victim is a great start.

other companies do it too.

nokia dictates how to hold their phones:
<http://funsizebytes.com/post/745721120/instructions-from-my-nokia-2320>

here's another:
<http://i48.tinypic.com/x0xsi9.jpg>

there are plenty of others.

> <http://www.ifixit.com/Teardown/iPhone-4-Teardown/3130/2>
> Apple has gone a step further and tuned the phone to utilize
> whichever network band is less congested or has the least
> interference for the best signal quality, regardless of the
> actual signal strength. Early reports suggest this feature,
> while buggy in its early stages, will greatly improve the
> phone's reliability on AT&T's fragile network.
> Translation: Apple uses the SNR (signal quality) and not the signal
> strength (-dBM) to control the phone.

some other phones also use snr. there was an issue way way back with
sprint where people would complain that one phone showed the maximum
number of bars and another sitting right next to it had 1-2 bars. the
reason that one showed snr and the other showed strength.

i don't remember which phones those were, but i do remember the nokia
6185 having horrible reception compared to just about every other
sprint cellphone at the time. no lawsuits for that one though.

> From various reports, the iPhone 4 drops more like 3-4 bars when the
> antenna tip is touched. If that's true (I haven't played with an
> iPhone 4 yet), that's a -30dB or more drop, which is far too sensitive
> to survive hand contact.
>
> My very unofficial conversion table from -dBm to bars:
> Bars -dBm
> 1 -102 to -112
> 2 -94 to -101
> 3 -87 to -93
> 4 -77 to -86
> 5 -38 to -76
> tested on my VX8100.

according to anandtech tests, it's: -113, -107, -103, -101, -91, -51

<http://www.anandtech.com/show/3794/the-iphone-4-review/2>

it also says:

I can honestly say that I've never held onto so many calls and data
simultaneously on 1 bar at -113 dBm as I have with the iPhone 4, so
it's readily apparent that the new baseband hardware is much more
sensitive compared to what was in the 3GS. The difference is that
reception is massively better on the iPhone 4 in actual use.

> Note that projecting external antennas have been on cell phones since
> the stone age. Internal antenna are a recent development. Touching
> the antenna on an old external antenna cell phone had little effect,
> so it's there's no reason an external antenna shouldn't work on the
> iPhone 4. Something else is going on, but without an iPhone 4 to play
> with, I'm guessing.

holding the pull-out antenna has an effect on my old cellphone, and the
instructions that came with it say not to do that.

Justin wrote:
> Richard B. Gilbert wrote on [Sat, 03 Jul 2010 15:38:32 -0400]:
>> Justin wrote:
>>> Richard B. Gilbert wrote on [Sat, 03 Jul 2010 14:40:59 -0400]:
>>>> Justin wrote:
>>>>> Larry wrote on [Sat, 03 Jul 2010 14:27:22 +0000]:
>>>>>> Justin <[email protected]> wrote in news:[email protected]
>>>>>> september.org:
>>>>>>
>>>>>>> data mining.
>>>>>> Precisely my point about the horrors of cloud computing.....
>>>>> yep, however this point had nothing to do with the cloud
>>>> Who is responsible for the integrity and security of data stored "in the
>>>> cloud"? Why should I, or anyone, be willing to entrust his data to it?
>>> That's why I encrypt the data I sent to my cloud backup service. My email
>>> already travels unencrypted across less trustworthy servers than google
>>> between the end user hitting send and me receiving it. I trust comcast
>>> a whole bunch less than google. AT&T even less than Comcast, yet how
>>> many people use one of those as their ISP?
>>>
>>> The cloud is not a single entity, it's Amazon, it's Google, it's Microsoft,
>>> it's facebook, it's Yahoo, etc.
>>> You need to pick who you want to trust and for what service. It's no different
>>> than trusting your doctor with your medical records. Or perhaps which pharmacy
>>> you trust when you fill your prescription.
>>>
>> Thanks!
>>
>> I think I will continue to backup my phone to my computer. I also have
>> very similar data on my PDA if I should happen to need it. If all three
>> sources are somehow destroyed I probably won't be in any condition to
>> care!
>
> That's a nice theory, but if you are at the grocery store during a storm and your
> house is blown away with your computer, and you get caught in a heavy downpour and your
> phone gets wet and stops working, you can still be in pretty good condition
> and have lost it all.

I think I can take that risk!

nospam wrote:
> In article <[email protected]>, Jeff
> Liebermann <[email protected]> wrote:
>
>>> "More suits filed in iPhone 4 antenna fracas"
>>> <http://news.cnet.com/8301-31021_3-20009625-260.html>
>> At first, Apple said this was a problem common to any phone
>> and suggested buying a rubber case or holding the phone
>> differently.
>> Translation: Apple doesn't have a clue about RF and is now in damage
>> control mode. Blaming the victim is a great start.
>
> other companies do it too.
>
> nokia dictates how to hold their phones:
> <http://funsizebytes.com/post/745721120/instructions-from-my-nokia-2320>
>
> here's another:
> <http://i48.tinypic.com/x0xsi9.jpg>
>
> there are plenty of others.
>
>> <http://www.ifixit.com/Teardown/iPhone-4-Teardown/3130/2>
>> Apple has gone a step further and tuned the phone to utilize
>> whichever network band is less congested or has the least
>> interference for the best signal quality, regardless of the
>> actual signal strength. Early reports suggest this feature,
>> while buggy in its early stages, will greatly improve the
>> phone's reliability on AT&T's fragile network.
>> Translation: Apple uses the SNR (signal quality) and not the signal
>> strength (-dBM) to control the phone.
>
> some other phones also use snr. there was an issue way way back with
> sprint where people would complain that one phone showed the maximum
> number of bars and another sitting right next to it had 1-2 bars. the
> reason that one showed snr and the other showed strength.
>
> i don't remember which phones those were, but i do remember the nokia
> 6185 having horrible reception compared to just about every other
> sprint cellphone at the time. no lawsuits for that one though.
>
>> From various reports, the iPhone 4 drops more like 3-4 bars when the
>> antenna tip is touched. If that's true (I haven't played with an
>> iPhone 4 yet), that's a -30dB or more drop, which is far too sensitive
>> to survive hand contact.
>>
>> My very unofficial conversion table from -dBm to bars:
>> Bars -dBm
>> 1 -102 to -112
>> 2 -94 to -101
>> 3 -87 to -93
>> 4 -77 to -86
>> 5 -38 to -76
>> tested on my VX8100.
>
> according to anandtech tests, it's: -113, -107, -103, -101, -91, -51
>
> <http://www.anandtech.com/show/3794/the-iphone-4-review/2>
>
> it also says:
>
> I can honestly say that I've never held onto so many calls and data
> simultaneously on 1 bar at -113 dBm as I have with the iPhone 4, so
> it's readily apparent that the new baseband hardware is much more
> sensitive compared to what was in the 3GS. The difference is that
> reception is massively better on the iPhone 4 in actual use.
>
>> Note that projecting external antennas have been on cell phones since
>> the stone age. Internal antenna are a recent development. Touching
>> the antenna on an old external antenna cell phone had little effect,
>> so it's there's no reason an external antenna shouldn't work on the
>> iPhone 4. Something else is going on, but without an iPhone 4 to play
>> with, I'm guessing.
>
> holding the pull-out antenna has an effect on my old cellphone, and the
> instructions that came with it say not to do that.

That makes sense! Any antenna intended for use by a transmitter must be
carefully matched to the transmitter. If carefully done, most of the
transmitter's signal is radiated which is what you want. Modifying the
antenna, e.g. by adding part of your body, can result in an impedance
mismatch which can cause the signal to be reflected back into the
transmitter rather than being radiated, which, being translated, means
that your call may not go through or you may get very poor reception or
both.

I think that most modern cell phones use only an internal antenna. Some
of the older phones had a telescoping antenna a whole three or four
inches long.

In article <[email protected]>, Todd Allcock
<[email protected]> wrote:

> I like that meter. My HTC-built Sony X1 (great PDA, terrible phone)
> switches from 5 bars to 4 at -90 dbm. That's a meter designed to "hide"
> a lousy phone! Consequently, I get very little warning before losing
> signal entirely. The bars drop from 5 to 0 rather quickly in weak areas.

they're deceiving you. time for a lawsuit.

In article <[email protected]>,
John Navas <[email protected]> wrote:

> "More suits filed in iPhone 4 antenna fracas"
> <http://news.cnet.com/8301-31021_3-20009625-260.html>

Strange why people are just complaining about the new phone, my 3GS has
always dropped signal strength remarkably if I hold it with my hand
around the top half/

The difference is that it will go from 3bars to no bars depending on how
I hold it, and that is with a case on it

David

On Sun, 04 Jul 2010 10:21:31 +1000, in
<[email protected]>, David
<[email protected]> wrote:

>In article <[email protected]>,
> John Navas <[email protected]> wrote:
>
>> "More suits filed in iPhone 4 antenna fracas"
>> <http://news.cnet.com/8301-31021_3-20009625-260.html>
>
>Strange why people are just complaining about the new phone, my 3GS has
>always dropped signal strength remarkably if I hold it with my hand
>around the top half/
>
>The difference is that it will go from 3bars to no bars depending on how
>I hold it, and that is with a case on it

It can be normal for signals bars to fluctuate even when not touching
the phone or moving. Some phones, for example, will switch back and
forth between the signal strength of home and foreign networks. This
can be very frustrating when a foreign network has a good signal and the
home network has a poor signal, but the phone is only allowed on the
home network.

--
Best regards,
John

If the iPhone and iPad are really so impressive,
then why do iFans keep making excuses for them?

On Sat, 03 Jul 2010 15:05:02 -0700, nospam <[email protected]>
wrote:

>nokia dictates how to hold their phones:
><http://funsizebytes.com/post/745721120/instructions-from-my-nokia-2320>
>here's another:
><http://i48.tinypic.com/x0xsi9.jpg>
>there are plenty of others.

True. Samsung has a sticker on some of their models warning users to
keep their hands off the bottom of the phone. However, that wasn't my
point. However, there's a difference between these phones and the
iPhone 4. All of these phones will experience some reduction in
signal strength (which causes a corresponding increase in TX power on
the handset and cell site to compensate). Except in really really
weak and marginal areas, I've never had a disconnect when grabbing the
antenna on any of my phones (extendable or otherwise). Yet, the
iPhone 4 causes a disconnect, which suggests that the signal loss is
far more drastic than what has been observed on these other phones.

>some other phones also use snr. there was an issue way way back with
>sprint where people would complain that one phone showed the maximum
>number of bars and another sitting right next to it had 1-2 bars. the
>reason that one showed snr and the other showed strength.

It varies by chipset. Both RSSI and SNR are available. I'm fairly
sure the bar graph uses RSSI.

I don't use bars. I use the signal strength and SNR (Eb/No) provided
by the field test mode.
<http://www.wpsantennas.com/pdf/testmode/FieldTestModes.pdf>
In phone mode dial *3001#12345#* then press CALL.
The Field Test Screen will appear. Select Cell Information.
Signal Strength is on the top line after RX-. Frequency
follows FQ and is based on the channel number (i.e. 100-200
is 800 MHz and 500-700 is 1900MHz). The top line displays
information about the tower you are using. The lines below
display info about your neighboring towers.

I just tried the covering hand test with a Motorola RAZR V3M on
Verizon. Signal level dropped -6 to -9dBm when covered by my hand.
That's about 1 bar and maybe 2 bars drop.

Incidentally, long ago, in a cell phone store long gone, I was
standing in line waiting to ask some dumb question of the salesman.
Ahead of me was the salesman and a lady looking at various phones
spread around the table. Undecided as to which one to purchase, the
salesman suggested picking the one with the largest number of bars.
Over the years, the manufacturers and service providers have known
about this effect, and tend to tweak the RSSI to bars conversion table
to make more bars appear. My Verizon XV6700 would work just fine with
no bars showing. Some other phones I've tried wouldn't work with 1
bar showing.

>> My very unofficial conversion table from -dBm to bars:
>> Bars -dBm
>> 1 -102 to -112
>> 2 -94 to -101
>> 3 -87 to -93
>> 4 -77 to -86
>> 5 -38 to -76
>> tested on my VX8100.

>according to anandtech tests, it's: -113, -107, -103, -101, -91, -51
><http://www.anandtech.com/show/3794/the-iphone-4-review/2>

What I did to measure mine was attach an external antenna to the
phone, and bury the phone inside a home made shielded enclosure. I
then used a step attenuator in the antenna line to adjust the signal
level. The signal level in -dBm would change rather rapidly, while I
had to wait perhaps 10 seconds for the bars to change. There was
considerable guesswork involved, but I think I was close.

Yet another dBm to bars table:
<http://forums.crackberry.com/f3/change-5-bar-display-signal-power-dbm-26381/>

>it also says:
>
> I can honestly say that I've never held onto so many calls and data
> simultaneously on 1 bar at -113 dBm as I have with the iPhone 4, so
> it's readily apparent that the new baseband hardware is much more
> sensitive compared to what was in the 3GS. The difference is that
> reception is massively better on the iPhone 4 in actual use.

Oh rubbish. Just because it indicates 1 bar doesn't mean the signal
is near the noise floor. Ask the author to supply some signal levels
in dBm (and SNR) for a decent minimum usable level comparison.
Incidentally, it's rarely the receiver in the handset that limits
range and reliability. It's the receiver at the cell site, that has
to handle overload from other sites, large dynamic range, and
considerable multipath, while retaining decent sensitivity, that
usually limits performance. The cell site xmitter can crank up the TX
power to 1 or 2 watts (depending on band), while the typical handset
can deliver maybe 100mw on a good day with a charged battery. Any
more and users will be complaining that the battery doesn't last.

>holding the pull-out antenna has an effect on my old cellphone, and the
>instructions that came with it say not to do that.

True. It has an effect, but it probably did NOT cause a disconnect.


--
Jeff Liebermann [email protected]
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

On Sat, 03 Jul 2010 14:40:59 -0400, Richard B. Gilbert <[email protected]> wrote:

> Justin wrote:
>> Larry wrote on [Sat, 03 Jul 2010 14:27:22 +0000]:
>>> Justin <[email protected]> wrote in news:[email protected]
>>> september.org:
>>>
>>>> data mining.
>>> Precisely my point about the horrors of cloud computing.....
>>
>> yep, however this point had nothing to do with the cloud
>
> Who is responsible for the integrity and security of data stored "in the
> cloud"? Why should I, or anyone, be willing to entrust his data to it?

Case in point: the T-Mobile/Microsoft/Danger/Sidekick data-loss fiasco
not that long ago. Has all that lost data been reconstructed yet?

Cheers, -- tlvp
--
Avant de repondre, jeter la poubelle, SVP

In article <[email protected]>, Jeff
Liebermann <[email protected]> wrote:

> True. Samsung has a sticker on some of their models warning users to
> keep their hands off the bottom of the phone. However, that wasn't my
> point. However, there's a difference between these phones and the
> iPhone 4. All of these phones will experience some reduction in
> signal strength (which causes a corresponding increase in TX power on
> the handset and cell site to compensate). Except in really really
> weak and marginal areas, I've never had a disconnect when grabbing the
> antenna on any of my phones (extendable or otherwise). Yet, the
> iPhone 4 causes a disconnect, which suggests that the signal loss is
> far more drastic than what has been observed on these other phones.

some users report call drops on the iphone 4 and others don't.

> >some other phones also use snr. there was an issue way way back with
> >sprint where people would complain that one phone showed the maximum
> >number of bars and another sitting right next to it had 1-2 bars. the
> >reason that one showed snr and the other showed strength.
>
> It varies by chipset. Both RSSI and SNR are available. I'm fairly
> sure the bar graph uses RSSI.

it depends on the phone. i know my old denso touchpoint displayed snr
(and a fantastic phone).

> I don't use bars. I use the signal strength and SNR (Eb/No) provided
> by the field test mode.

you'll be disappointed to learn that the iphone 4 has removed field
test mode. anandtech managed to hack a level indicator back (but not
the full field test mode) in by restoring a jailbroken backup which had
some preference tweaked.

> Incidentally, long ago, in a cell phone store long gone, I was
> standing in line waiting to ask some dumb question of the salesman.
> Ahead of me was the salesman and a lady looking at various phones
> spread around the table. Undecided as to which one to purchase, the
> salesman suggested picking the one with the largest number of bars.
> Over the years, the manufacturers and service providers have known
> about this effect, and tend to tweak the RSSI to bars conversion table
> to make more bars appear. My Verizon XV6700 would work just fine with
> no bars showing. Some other phones I've tried wouldn't work with 1
> bar showing.

that's the thing, people want to see bars, but it really doesn't mean
much. i've had successful calls with 1 bar and i've had drops with 5
bars.

> >it also says:
> >
> > I can honestly say that I've never held onto so many calls and data
> > simultaneously on 1 bar at -113 dBm as I have with the iPhone 4, so
> > it's readily apparent that the new baseband hardware is much more
> > sensitive compared to what was in the 3GS. The difference is that
> > reception is massively better on the iPhone 4 in actual use.
>
> Oh rubbish. Just because it indicates 1 bar doesn't mean the signal
> is near the noise floor. Ask the author to supply some signal levels
> in dBm (and SNR) for a decent minimum usable level comparison.
> Incidentally, it's rarely the receiver in the handset that limits
> range and reliability. It's the receiver at the cell site, that has
> to handle overload from other sites, large dynamic range, and
> considerable multipath, while retaining decent sensitivity, that
> usually limits performance. The cell site xmitter can crank up the TX
> power to 1 or 2 watts (depending on band), while the typical handset
> can deliver maybe 100mw on a good day with a charged battery. Any
> more and users will be complaining that the battery doesn't last.

the takeaway from that is there are many factors that contribute to a
call drop, and also that it's really hard to do a controlled
experiment.

nevertheless, his experience is as valid as anyone elses, and he found
reception to be better, and measured an increase in wifi strength when
touching the antenna.

On Sat, 03 Jul 2010 19:12:56 -0400, "Richard B. Gilbert"
<[email protected]> wrote:

>That makes sense! Any antenna intended for use by a transmitter must be
>carefully matched to the transmitter.

Yep. In the case of the iPhone 4, there are two antennas.
<http://www.anandtech.com/show/3794/the-iphone-4-review/2>
The small one has to do just 2.4Ghz. The larger one has to do 800,
900, 1800, and 1900MHz. Matching a single frequency is easy. Matching
a wide range of frequencies is not.

>If carefully done, most of the
>transmitter's signal is radiated which is what you want.

Radiating all the signal (efficiency) is only part of the problem. The
RF needs to radiate away from the users brain in order to meet the FCC
SAR (specific absorption rate) limit.
<http://www.anandtech.com/show/3794/the-iphone-4-review/2>
Oh wait... the user bought an iPhone 4, so the brain is already
presumed damaged.



--
Jeff Liebermann [email protected]
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

On Sat, 03 Jul 2010 20:59:37 -0700, nospam <[email protected]>
wrote:

>some users report call drops on the iphone 4 and others don't.

The AnandTech review showed a -24dB max drop in signal level when the
phone is improperly held:
<http://www.anandtech.com/show/3794/the-iphone-4-review/2>
That's huge. That's about a 1/250th decrease in signal. As the
author indicates, if the phone has a fairly strong signal to start
with, it won't drop the call. However, if the signal is modest or
weak to start with, a -24dB decrase will drop the call. I never saw
anything near -24dB drop when fondling the antennas on various cell
phones. My first guess was too high an antenna Q. I then guessed
VSWR shutdown. Maybe my first guess was right?

>you'll be disappointed to learn that the iphone 4 has removed field
>test mode.

Yep. I'm not surprised. AT&T got severely embarassed when Verizon
published the real map of their 3G network. Since they can't build
the network fast enough, might as well remove the tools needed to
attach numbers to the coverage.

Apple: You don't need to know.
AT&T: We don't want you to know.

>that's the thing, people want to see bars, but it really doesn't mean
>much. i've had successful calls with 1 bar and i've had drops with 5
>bars.

I suppose if this becomes a trend, the range from 1 to 5 bars will be
from minimum detectable signal, to where the BER goes flat line.
Anything over that gets 5 bars. Reading the description in the above
URL, that appears to be what's happening in the iPhone 4.

>the takeaway from that is there are many factors that contribute to a
>call drop, and also that it's really hard to do a controlled
>experiment.

Yep. Worse, when the system is really busy, like during rush hour,
VZW will drop calls that have been running for over 10-15 minutes to
make room for new callers. I suspect the other service providers are
doing something similar. It's really difficult to tell what caused a
call to drop from the handset end.

--
Jeff Liebermann [email protected]
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

In article <[email protected]>, Jeff
Liebermann <[email protected]> wrote:

> >that's the thing, people want to see bars, but it really doesn't mean
> >much. i've had successful calls with 1 bar and i've had drops with 5
> >bars.
>
> I suppose if this becomes a trend, the range from 1 to 5 bars will be
> from minimum detectable signal, to where the BER goes flat line.
> Anything over that gets 5 bars. Reading the description in the above
> URL, that appears to be what's happening in the iPhone 4.

showing ber on the main screen would be very useful. my old touchpoint
phone showed ber in test mode and actually had the most informative
test mode i've ever seen, with 2-3 pages of data including cells it was
talking to and the ones to which it was considering switching.

> >the takeaway from that is there are many factors that contribute to a
> >call drop, and also that it's really hard to do a controlled
> >experiment.
>
> Yep. Worse, when the system is really busy, like during rush hour,
> VZW will drop calls that have been running for over 10-15 minutes to
> make room for new callers. I suspect the other service providers are
> doing something similar.

are you referring to cdma cell shrinkage? that is *really* hard to
explain to people.

> It's really difficult to tell what caused a
> call to drop from the handset end.

right, and people are blaming the iphone antenna, without having ruled
out other causes.

On 03/07/10 9:35 PM, Jeff Liebermann wrote:
> On Sat, 03 Jul 2010 20:59:37 -0700, nospam<[email protected]>
> wrote:
>
>> some users report call drops on the iphone 4 and others don't.
>
> The AnandTech review showed a -24dB max drop in signal level when the
> phone is improperly held:
> <http://www.anandtech.com/show/3794/the-iphone-4-review/2>
> That's huge. That's about a 1/250th decrease in signal. As the
> author indicates, if the phone has a fairly strong signal to start
> with, it won't drop the call. However, if the signal is modest or
> weak to start with, a -24dB decrase will drop the call. I never saw
> anything near -24dB drop when fondling the antennas on various cell
> phones. My first guess was too high an antenna Q. I then guessed
> VSWR shutdown. Maybe my first guess was right?
>
>> you'll be disappointed to learn that the iphone 4 has removed field
>> test mode.
>
> Yep. I'm not surprised. AT&T got severely embarassed when Verizon
> published the real map of their 3G network.

So much so that they launched a bogus lawsuit against Verizon.

On Sat, 03 Jul 2010 21:42:45 -0700, nospam <[email protected]>
wrote:

>> Yep. Worse, when the system is really busy, like during rush hour,
>> VZW will drop calls that have been running for over 10-15 minutes to
>> make room for new callers. I suspect the other service providers are
>> doing something similar.
>
>are you referring to cdma cell shrinkage? that is *really* hard to
>explain to people.

No, not CDMA cell breathing, although that could contribute to
disconnects.
<http://www.macltd.com/datafile_downloads/MAC%20Ltd%20-%20Cell%20Breathing.pdf>
It's just an increase in the noise floor with CDMA causing a decrease
in usable range.

What's happening is the Verizon got too many complaints about busy
signals and incoming calls going directly to voice mail. Since the
cell capacity could not be easily or economical increased without
additional frequencies, Verizon opted to kick off the ratchet jaw
yackers and allow new calls to have priority, when the system gets
busy. That eliminated most of the busy signals. Meanwhile, those
getting kicked off never suspected that the call was intentionally
dropped, and probably guessed that they had driven through a weak
signal area, or that a handoff had failed. It's possible that VZW is
also dropping weak (low SNR) calls when the system gets busy, on the
assumption that they're going to drop out anyway.

--
Jeff Liebermann [email protected]
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558