Hands-On Review: using a cellular modem with a
Dell Latitude notebook/laptop portable
computer
July 21/04 - PLEASE NOTE: This article
has been left here for legacy purposes (scrapped my
analog phone).
June 7/99 -
Being a systems administrator for
an international web hosting service
is not an easy job. It requires constant
attention to email, fax, telephone and server
communications, with days that often run from 5:00 AM to
midnight. Any notion I had about being able to travel for
a few days without being in constant touch with our
clients would quickly set the stage for the demise of our
business.
With this in mind, I decided it was time to
implement a portable laptop or notebook system in conjunction
with the cellular phone system that would give me the ability
to leave the office from time to time and provide additional
redundancy for the upcoming Y2K millennium adventure. This is
the story of my experience ...
Some of the topics covered in this article:
-using laptops and notebooks to connect to the
internet via cellphone
-connecting to the net using your long distance
credit card via standard phone
-using high gain antennas to boost cell
performance
-using dual hard drives for near instant data
backup and recovery
After spending many months
researching the market, I decided to go with Dell
Computer Corporation because it seemed like they had a
good combination of reliability, top notch technology and
support. The price was also reasonable, although somewhat
higher than a 'no name' brand, but the cost is a
secondary factor when you're dealing with a 'mission
critical' situation as is the case with our
business.
Some of the 'must have' features on our want
list:
|
14" XGA (1024 x 768 pixels) screen
with true color 24 bit display (16.7 million
colors). |
|
Touchpad and usable keyboard with
inverted-T cursor keys. |
|
Second hard drive capability for
fast backup. |
|
Reasonably fast processor (at least
300 MHz) with 64 Mb RAM |
|
Built-in CD ROM, floppy and LS-120
superdrive. |
|
S video out for DVD display on
external TV. |
|
Good battery life (> 3 hours)
with fast recharge (1
hour). |
|
On-site service warranty
(international). |
|
Durability and reasonable
compactness. |
|
Business lease
financing. |
So I hit the Dell website
flying with 'latitude' on my mind,
configured the notebook the way I wanted
and placed the order. The request was
answered promptly and shortly thereafter,
my machine was being prepared.
I had already bought a 3Com
(Megahertz) PCMCIA cellular capable modem, so
I'll be ready to test the cell roaming
capabilities when the notebook arrives by June
22. We'll be using an extra powerful cellphone
and experimenting with directional antennas for
extended area coverage (documented with
pictures taken on our Nikon Coolpix 100 digital
camera). I'll also be looking into the new
Iridium and Globalstar satellite phone system
as an alternative to the cellular
system.
June 22/99 -
I was just hoisting my
third cup of coffee this
morning when I heard a vehicle pulling up
outside. Indeed, it was the courier
arriving with the laptop. I signed off
for it and eagerly opened the carton to
inspect the contents.
Everything was well packed,
with supporting documentation visible as soon
as the box was opened. I removed the accessory
tray, pulled the laptop out of the plastic bag
and turned it on ... voila! It booted up from
battery, presented a welcome screen from Dell
and, after entering the CD key number and a few
other things, went straight into Win 98.
I grabbed my Nikon Coolpix
digital camera out of its nifty belt pack
(anywhere, anytime, no developing), snapped a
few pictures and then plugged it into one of
the PCMCIA card slots. Windows immediately
recognized the camera as another hard drive and
I copied the JPEG files onto the hard disk,
transferred the pix to a floppy, updated this
article and finished my coffee. No fuss, no
muss, no hassle!
If I was going to use the
camera to produce printed output, I would opt
for a higher resolution model -but, for getting
pix up on the 'net quickly, it can't be
beat.
|
 |
Is this going to work as a
desktop replacement for me? (I use a 17"
Viewsonic in my lab, probably the best picture
quality ever) - I think so, after seeing how
bright and sharp the photo-realistic screen is
(picture doesn't do it justice).
AUTHOR'S NOTE:
May/00
The 6.4 Mb drive failed and was
replaced under warranty. The first
replacement attempts were with
several identical
refurbished IBM drives which
were defective upon arrival. They
then substituted a Fujitsu drive
which is still working today.
Nevertheless, I wasn't pleased
about receiving refurbished drives
for a brand new, high end laptop -
so I looked around and bought a new
IBM 20 GB Travelstar drive, and it
has worked extremely well, very
quiet and fast. |
I'll comment fully on it after I
pick up my cell phone equipment and
install the modem.
June 27/99
- The first thing that
greets you
when you power up the CPt
is a welcome screen from
Dell. When Windows
launches, there are icons
conveniently provided on
the desktop that permit
direct access to the html
based documentation, so
it really isn't necessary
to read the hard copy
manuals even though
several are provided.
Another nice touch is a
Dell applet that prompts
you to make floppies
containing all the system
drivers in case you ever
have a catastrophic hard
drive failure. These
driver disks, along with
the Win 98 CD will enable
you to reconstruct your
system quickly.
After backing
up my drivers, I decided to
take a look at how the 6.4 Gb
hard drive had been configured
at the factory.
AUTHOR'S
NOTE:
May/02
The back lighting
for the screen
started to fail,
making it hard to
see. The entire
display unit was
promptly replaced
under
warranty. |
It turned out
that it was divided into
three partitions, all
running the 16 bit FAT
file system. I wanted the
hard drive divided into
two equal partitions
(primary and backup) and
I also had expectations
of taking full advantage
of the newer 32 bit FAT
system so that I could
maximize my hard disk
sector and space
utilization.
However, if I
changed the disk structure
using the Windows FDISK
utility, I would have lost all
the data, including the
pre-configuration of Windows
that Dell had installed. This
didn't seem like a good idea,
so I elected to run out and
purchase the Partition Magic
program from Power Quest. This
product allows you to
re-configure your hard drive
'on the fly' without losing any
data; in very short order I had
the system running smoothly,
just the way I wanted it,
without having to re-install
Windows, etc. It's the kind of
program you hardly ever need,
but when you need it, you need
it bad!
My next step
was to transfer all the data
from my desktop system so while
I was out and about, I also
purchased a special parallel
port cable so that I could run
the Windows Direct Cable
Connection program. This is not
the fastest way to transfer
data, but it works well enough
for a one-time or occasional
activity. If I was doing this
often, I would certainly
purchase something like
Laplink, USB hardware or a
network card. After letting it
run all night (yes, moving 2 Gb
of data is slow), I came back
in the morning and my mobile
desktop replacement system was
ready to go.
|
The
Dell laptops come with a
built-in touchpad that
works very well as a
mouse replacement,
largely due to the
presence of a really
nifty driver from
Synaptics. It permits
vertical page scrolling
by stroking the right
hand edge of the touchpad
(likewise horizontal
scrolling by sliding your
finger along the bottom
edge). It even let's you
'coast' through a long
page if you swipe it
quickly and let your
finger fly off the edge,
stopping the scrolling
action only when you tap
the touchpad (yes, you
can control the speed).
The more I use it, the
better I like it and it
certainly is handy when
you just need to turn on
the computer and do
something easy, like
downloading your email,
without having to drag
out the mouse.
However, I
still like to 'mouse around' so
while I was out, I had also
grabbed a new Microsoft
IntelliMouse with the scroll
wheel. When I plugged it into
the PS2 port, the Synaptics
driver recognized its presence
and disabled the touchpad,
allowing all the IntelliMouse
features to come into play. I
also installed the IntelliMouse
driver, but discovered it
clobbers the Synaptics driver
for the touchpad (and doesn't
really provide any additional
functionality), so I used the
driver disks I had made earlier
to restore the Synaptics
driver. The scroll wheel also
works very well; when you click
the scroll wheel button, you
can scroll a page vertically
just by moving the mouse up or
down on the page - you don't
need to move the cursor over to
the elevator bar and click on
it anymore. You can also rotate
the scroll wheel to generate
the same effect, but I found
that this operation was not as
consistent in all programs as
the scroll wheel button is,
although this might be
something to do with the
Synaptics
driver.
AUTHOR'S
NOTE:
Sep/01
The keyboard failed
and was replaced
promptly under
warranty. |
By
the time I reached this
point, I was getting
quite used to the new
system and found that I
was really starting to
enjoy using it.
Everything works well -
the hard drive is fast
and the CPU snaps
programs up on the sharp,
bright screen in a flash.
I have also enjoyed the
versatility of being able
to swap various different
drives in and out of the
media bay. The battery
lasts for over 3 hours
and I find it very
liberating to be able to
move around and work
wherever I want instead
of being confined to my
office all
day.
AUTHOR'S
NOTE:
Jun/02
The battery failed
and I had to pay
for a new one as
the warranty
doesn't cover it
after a year. It
was hardly ever
used off 110 VAC,
very few
charge/discharge
cycles, but it died
(zero output all of
a sudden) anyway.
Of course, it was
one of the few
times I was using
it on battery power
and I lost data
because of
it. |
I
haven't tried the
specified torture test of
pouring coffee between
the 'h' and 'j' keys yet
(from 4", with cream and
sugar), but something
tells me it really could
handle
this.
|
Next,
I installed my
Megahertz/3Com cellular
modem, hooked it up to my
landline using the handy
Xjack retractable
connector and logged onto
the net. The first thing
I did was go to the 3Com
website and download the
flash upgrade for the
modem bios. I ran the
flash upgrade program,
but when it reached the
10% stage, it quit the
bios replacement and gave
me an error message,
something like 'file
transfer failed'. A chill
ran down my spine and
then I broke out into a
cold sweat as I realized
I may have toasted the
most expensive modem I've
ever owned. I've heard
some woeful stories about
modems being destroyed
during the flash process
and I didn't need to find
out that this had
happened to me. I
rebooted the laptop, hit
the dial-up connect icon
and muttered a short
Bhuddist prayer. Much to
my extreme relief, it
logged on and even
downloaded a new order
from a client!
I zoomed back
to the 3Com website, but
couldn't find any reference to
the problem in their knowledge
base. So, I picked up the
phone, called their tech
support and got a support
person on the line in short
order (toll-free). He knew
exactly what the problem was
and instructed me to reduce the
buffer settings while the
update was being performed.
This worked just like a charm
and my panic level subsided;
faith in 3Com was restored.
I had also
noticed that I couldn't hear my
modem dial-up when I was
connecting to the net even
though the speaker setting was
on; although the PCMCIA modems
don't have an internal speaker,
they are supposed to be able to
feed the line audio into the
Windows sound system. This was
troubling because I have learnt
over time to interpret the
handshaking signals (i.e.
squawks and bleeps) and know
when I've hit a bad modem or
other problem.
Since I had a
few other minor issues to
resolve, I decided to give the
Dell mobile support team a
quick call and see if they
could help. The contact
information is prominently
displayed in the support notes
and I found myself talking to a
friendly technician in very
short order. He was very
helpful and we actually had a
long discussion ranging over
numerous topics; I found that
he was in no hurry to dump the
call. After hanging up, I tried
the things he suggested, but
unfortunately, it still doesn't
work. So I've sent off some
email in the hopes that they
can find something else to try,
but if they can't I still feel
that they did a good job,
especially since the modem is
from another supplier. My
guess, though, is that it's a
problem with the laptop audio
driver because the Win 98
'toggle keys' sound doesn't
come through either (author's
note: in the end, it turned out
to be a bios problem, solved by
the release of Bios version
A01).
Nevertheless,
the modem is working fine and
consistently logs on at 44 to
50k. The compression algorithms
seem very good as everything
downloads very quickly and I
haven't yet had a failed
connection, so not having the
dial-up audio monitoring hasn't
been much of a problem so far.
I have also traveled out of our
local calling area and tried
connecting long distance to our
modem pool, using my telephone
credit card - it worked
perfectly. If you try this,
make sure you check the
'Operator assisted or manual
dial' setting on the 'Options'
tab for your modem settings.
This causes Windows to bring up
a dialog box when you hit the
'Connect' button; this allows
you to manually dial your long
distance number, wait for the
tone and enter your credit card
number. When the modem pool
answers, you just hit the
'Continue' button on the
screen, hang up the phone and
the system logs on just as if
you were at home ... works like
a charm!
|
July 10/99 -
The most
difficult part of
connecting to the
'net via cellular has been
obtaining the correct data
cable that links my laptop to
the cellphone. There are
numerous types available,
depending on your cellphone
model and your laptop
modem. In the end, I had to
special order the 'Mot1'
cable for my equipment, which
set our schedule back
considerably.
I have an older
Motorola analog cellphone and I
decided to stay with this for a
number of reasons. The analog
system has much wider coverage than
the newer digital cells; it is also
higher power and uses a lower
frequency range, making it less
line-of-sight. I'm not particularly
concerned about the higher voice
quality and enhanced privacy of the
digital system, but the coverage
issue is of paramount interest to
me. The analog system gives me
excellent coverage in all the areas
I need and I am basically never out
of touch because of this.
Analog modems
don't work with digital phones, so
I couldn't see much point to having
a 'dual system' cellphone. You can
connect your analog modem to a
'dual' phone (provided it has the
proper connector), but as soon as
it detects a data operation, it
will automatically switch to analog
operation even if digital cells are
available. Some digital cellphone
providers allow you to connect
through the digital system by
attaching a cable from the serial
port on your laptop to the digital
cellphone (no analog modem is
involved or required), but this
will only work when you are within
range of a digital cell. Since
analog service is generally
available wherever digital is (the
converse is not true - yet), I
couldn't see the point of mucking
about with two different systems,
hence I settled for a pure analog
setup (for now). This also means
that the cellphone costs are lower,
although airtime is charged by the
minute rather than the second.
So, I connected
my expensive data cable to my
3Com/Megahertz modem, held my
breath, muttered another prayer and
hit the 'connect' button to dial-up
my service provider (Sprint). I
watched in sheer disbelief with my
'net monitoring software (NetMedic)
as the modem auto-deteced the
cellphone connection and the phone
number scrolled by on the cellphone
readout. The system logged on at
the (lately) unheard of speed of
4800 bps - wow, I thought, I'm
ON!!
|
Field
Testing
|
I stared at
it for a while, enjoying the
sense of elation. I then began
to wonder if I was experiencing
an unfounded sense of joy since
4.8K is not exactly cable-modem
speed. So, I opened my mail
program (Netscape) and, voila,
14 new messages began pouring
in. It wasn't as fast as I'm
used to, but hey, it worked
just fine - amazing! Then, I
tried surfing some pages with
large graphics and even that
worked well enough to convince
me that I didn't need to put my
browser into 'text only' mode.
I rattled off some quick
responses to the email, logged
off, and with a big smile on my
face, cracked open a bottle of
select brew that I had been
saving for this occasion. I
knew in that moment that a
whole new era in my life had
begun.
I'll
be field testing the
system over the next week
or so, seeking ways to
optimize performance and
reporting on the 'real
world' trials.
|
July 23/99
- The screen
froze just as
I was sitting down to
write a more detailed
account of some of my
experiences with cellular
phone behavior when
connecting to the net.
Hmm, I thought, I'm sure
I didn't hit the 'freeze'
button and I've yet to
have this thing crash on
me, what's up? The short
answer is that my IBM
hard drive went south and
I've just spent two days
going through computer
hell ...
I had
purchased the next-day onsite
service policy when I bought
the laptop, so I quickly got on
the phone to Dell tech support
to see how they could help. My
call was answered promptly and
after running a few diagnostic
tests with the tech over the
phone, he decided we wouldn't
waste time with a service call
- they'd just send another hard
drive right away by overnight
courier. Sure enough, it
arrived as promised at 11:30
the next morning.
The primary
hard drive is removed by
releasing a single screw on the
side of the laptop, so sliding
the bad one out and replacing
it with the new unit was
simple. However, I now faced
the daunting task of rebuilding
my system. Yes, I had backed up
my critical data onto my 120 Mb
'super floppy' disks, but I
still needed to re-install
Windows, all the system
drivers, all my programs (and
finding all the danged program
serial numbers) and some more
data that I had archived on our
office network system.
I had decided
not to buy the second hard
drive when I purchased the
system as it is a relatively
expensive option. I'm becoming
long in the tooth when it comes
to rebuilding computers and I
decided this was to be the last
time I go through this. The
fact of the matter is that hard
drives fail, no matter how old
they are, who makes them, etc.
The only workable solution I've
found is to run dual hard
drives as we do on our office
network system, one being a
bootable copy of the other. So,
I picked up the phone and
ordered the second hard drive;
when it arrives I'll discuss
the setup I use for this
configuration.
Meanwhile,
I've got my system back up and
running so I'll be writing more
about the cellular experience
shortly ...
|
July 28/99
- I owned a
communications
design/build
business for
over a decade, so
experimenting with UHF
(Ultra High Frequency
band) cell reception is
almost second nature to
me. I say 'almost'
because there are certain
peculiar anomalies
associated with the cell
system and it has taken
some time to understand
some of the
characteristic behavior I
have observed, especially
when connected to the
Internet. I decided to
keep things simple for
the first part of this
evaluation, so the
comments in this section
apply to my experiences
without any external
antennas or high power
'bag' phones; I'm just
using a Motorola
hand-held 'flip phone'
for now.
The analog
cell system was designed
primarily for voice
communications, not data, and
it works better for the former.
The switching circuitry at the
cell site is capable of
performing all kinds of
bandwidth management tricks to
better handle call volume,
particularly during 'dead air'
moments that occur regularly
with normal conversation. An
almost impertecptible pause in
human speech patterns is
actually a long, wasted period
of time for electronics that
analyze time domains at the
microsecond (one millionth)
level, so the system is
designed to switch the circuit
away from you during those very
brief periods and hand over the
'airtime' to someone else that
needs it at that moment. This
can be problematic for data
circuits that exchange
handshaking pulses and expect
measured responses in very
short periods of time.
Fortunately,
our local provider allows us to
prefix the call with a special
code that alerts the cell to
the fact that it is handling a
data call, which causes it to
react differently. I've found
that this usually means the
difference between connecting
at 4800 bps (without the data
prefix *3282) and 9600 bps
(with the prefix) - a speed
difference of 100%. Not all
providers incorporate this
feature - I certainly couldn't
use it in Washington, Idaho or
Montana, although I
occassionally still connected
at 9600 bps without it while in
'Roam' mode in those
states.
If the cell
is busy, especially combined
with a weak reception
condition, you can expect your
'net connection to get dropped
when you're right in the middle
of downloading your mail, just
as it used to with the feeble
modem connections we
experienced on the regular
P.O.T.S. (Plain Old Telephone
System) land line. This will
usually happen when someone
sends you some unsolicited spam
mail with a large file
attachment full of colorful
graphics. Naturally, because
the incoming mail delivery
wasn't completed, your remote
mail server behaves properly by
re-sending the mail from the
start of the first message in
the waiting batch as soon as
you re-establish your
connection and you're on only
long enough to find that the
same thing happens again. When
this occurs, say three or four
times, you may find that the
air around your current
location becomes quite colorful
too (usually blue).
However,
there are some things you can
do to alleviate this condition.
A short, 5 minute drive to
another location (especially
higher ground) can often bring
the cell signal level up to a
much higher level, with a
corresponding boost in the
integrity of your connection.
If you're near a highway, try
and move off of it down a side
road - aluminum-sided trucks
make great rolling reflectors
at these frequencies. Also,
keep in mind that fog, heavy
rain and electrical storms can
all have a negative impact on
your level of success. Don't
even think about connecting to
the 'net if you're in a moving
vehicle or a boat unless you
can hit the cell tower with a
water pistol.
If you are
travelling through a popular
tourist destination area, it
can also be a good idea to keep
going until you reach the next
cell that may not be so busy. A
fully loaded cell may try and
hand you off to another cell
some distance away that
actually is out of reach,
causing your signal strength to
jump back and forth between
'good' and 'no service', a very
confusing experience. If you're
staying in a resort area that
has only one local cell that is
running at capacity, you may
get better results by waiting
for off-peak times.
If you can't
move, most email client
programs have menu driven
options that allow you to block
messages larger than a certain
size from being downloaded, so
you can temporarily prevent the
large spam message from being
downloaded while you collect
the rest of your critical mail
from the server. If you do
this, keep in mind that you'll
eventually have to remove the
block and download the message
to properly reset your mail
queue. I've also found that it
is much better to log on
frequently and collect mail in
smaller batches during the day,
rather than waiting for one big
one at the end of the day.
In summary,
I've found the analog cell
coverage to be quite good and
I've managed to maintain
regular communications, albeit
with the help of some of the
above techniques from time to
time. It seems to be available
in all the places I've wanted
to go, so I'm not about to
order my Iridium or Globalstar
account yet. I lost it at the
6600' level going through Logan
pass in Montana, but it came
back quickly as we descended to
St. Mary's Lake. Yes, it can be
painfully slow at times, but
overall I have to say it has
worked well and has never
interfered with my daily work.
(yes, I'm well aware I haven't
received my first cell bill
yet). You'll learn quickly how
to monitor your signal strength
meter as you travel and pick
the good spots to log on
...
Of course,
you may often be staying in a
hotel or motel where you have a
phone available. If this is the
case, it may be more practical
to use your telephone credit
card to connect to your dial-up
service provider (say goodbye
to roaming charges and 4.8k).
Windows has a setting in the
modem options under Dial Up
Networking that allows you to
make a 'manual dial' call. If
you check this option, it will
wait until you dial the number
manually and enter your credit
card number. I carry a dual
outlet plug that allows me to
connect both the phone and the
modem into the line at the same
time for this purpose. You'll
need a phone system that has a
jack either at the wall or base
of the phone in order to do
this.
Visit one of
our clients for some more
cell information: Gecko
Beach
|

Good Cell
Location
|
August 9/99
- My second hard drive
arrived today
for my Latitude and I put
it to work immediately,
since I have firmly
resolved not to spend
another microsecond in
computer hell. It slides
easily into the exposed
media bay slot and locks
in place, so the physical
installation is about as
simple as it gets. The
software aspect is a
little more complicated,
but not too difficult if
you know
how.
AUTHOR'S
NOTE:
Nov/02
The expensive
second hard drive
failed 3 years
later, just after
the warranty
expired. It was
only used
occasionally as a
backup and was
never dropped. I
replaced both
internal drives
with the new IBM
Travelstar 40GNX 20
GB drives - super
quiet, super fast
and affordable ...
these days, you can
simply buy a USB
hard drive that
plugs into your USB
2.0 or firewire
port - makes a
great backup
solution! |
First,
you want this to be a
boot drive so that it can
take over at a moment's
notice if your primary
drive fails. The easiest
and safest way to prepare
it is to remove the
existing primary hard
drive and boot the laptop
from a floppy (you'll
need a boot floppy with
FDISK.exe and FORMAT.com
on it). The new drive
won't be recognized at
first (after you've
booted from the floppy)
because the boot sector
needs to be set with
FDISK, but once you've
done that, it will come
up as the primary hard
drive 'C'. Then, if you
run FORMAT.com with the
'/s' switch, it will be
bootable as your primary
drive.
Next, you'll
want to re-insert your original
hard drive so that the new
backup drive becomes the
secondary hard drive. After
that, you'll be ready to copy
the contents from your primary
hard drive to the new backup
hard drive. So, you go into
Explorer, click on the root
folder of drive 'C' and attempt
to copy it to drive 'D'. You
then get an error message that
says it can't be done and
you're sitting there,
scratching your head, wondering
why Microsoft won't allow you
to duplicate your hard drive
...
Fortunately,
there is a way to do it
(without buying a program like
DriveCopy). First, you should
temporarily disable the Windows
swap file (Control Panel >
System > Virtual Memory).
Then (after a reboot), use this
variation of the dos XCOPY
command:
xcopy C:\*.* /e /h /k /r /c
D:
This will
copy every file from your
primary hard drive over to your
secondary drive. Note that this
must be run from a dos window
while Windows is active. This
command should only be used the
first time you copy to a
freshly formatted drive. From
this point on, you should use
this variation of xcopy, which
will monitor the file archive
bit and only copy those files
that have changed:
xcopy C:\*.* /e /c /i /h /r /m
D:
You can put
this command into a batch file
and run it from a desktop icon.
The result: a fully bootable
backup drive that does the job
in less than 20 seconds a day
for most users! If your primary
drive fails, you just hit the
setup button, change the 'first
boot device' setting to the
media bay hard drive and voila!
- you're back in business while
you wait for your primary
replacement drive to
arrive.
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September 4/99
- Low
signal levels do have an
impact on the
efficiency of data
transmissions while connected
to the net via analog
cellphone. If the signal
strength is poor, the
connection will hang for a
number of seconds, continue
transmitting data, then hang
for a few more seconds. This
stop/start/stop/start
behavior can become tedious,
not to mention the effect it
has on airtime charges. It is
especially annoying when the
connection is dropped
altogether and the call has
to be re-established and the
mail download started all
over again.
I have
experienced these fringe situations
enough at this point to want to do
something about it. I purchased a
new Motorola DP 650EV (the 'V'
means you can set it to vibrate so
that your pocket doesn't ring) so
that I could be confident of having
the latest circuitry - it seems to
work better than my older 650, but
I don't like losing the 6 stage S
meter (new one has only 3 levels of
signal strength). The Motorola
phone also allows you to remove the
built-in rod antenna and plug in an
external antenna, as you can see in
the picture below. I used
industrial grade Velcro to attach
the cellphone to the edge of the
laptop screen.
Next, I bought a
marine whip antenna (no vehicle
ground plane required). This was a
waste of money as it didn't perform
any better than the built-in rod
antenna on the cellphone. I then
exchanged this for a Larsen YA5 800
directional yagi antenna (9 Dbi
forward gain) that you can also see
in the picture below. This made a
big difference; since I have been
using this in fringe areas, I've
had no trouble at all with my net
connections.
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Yagi Directional Beam
Antenna
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I'm going to
use a shorter cable since line
losses at these frequencies can
be quite significant, but even
with this long length of cable
it is a marked improvement.
Note the correct rotational
positioning re vertical
polarization. A slight tilt on
the horizontal axis can also
improve signal if the cell site
is high up on a mountain. The
narrowest elements are at the
front of the antenna (pointing
end).
I'll
be field testing the
system some more over the
next few months, seeking
ways to optimize
performance and reporting
on any significant
improvements. In January
or February of 2000, the
Iridium global satellite
system will become
'internet enabled' and we
hope to be able to test
the net capabilities at
that
time.
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