WiFi sensitivity question for Jeff Liebermann & anyone well versed in antennas

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In your experience with *both* Android & iOS mobile devices, have you also
found the iOS devices severely lacking in WiFi sensitivity (resulting in
dropped connections when Android devices are still working fine)?

This is a question borne out of experience setting up WiFi for dozens of
local neighbors, some of whom use Apple ipads & iPhones, and others who use
Android mobile equipment.

Almost always, in my own personal experience in my own large home with
multiple iPads and Android phones, and in the large homes of my neighbors,
the Apple iPads and iPhones almost always have *far worse* WiFi reception
than do the Android phones.

Has this been your experience also?
If so, why do you think this is the case?
-------------------------------------------
NOTE: Jeff is honest to a fault, so, his opinion matters greatly.

Re: WiFi sensitivity question for Jeff Liebermann & anyone well versed in antennas
On Sat, 30 Jul 2016 16:18:02 -0000 (UTC), Aardvarks

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Nope.  About the same range.  At least the same range within some
reasonable tolerance range, such as +/- 10% or so.  Note that I
consider "range" to be somewhat equivalent to your "sensitivity" where
"sensitivity" is limited to receive only and does not involve the
antenna or environmental situations.  Also note that anecdotal
evidence of a problem is not definitive as measurements such as
"range" and "sensitivity" tend to follow a bell curve.

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I'll resist the temptation to offer my opinion of Apple engineering
and RF design.  Well, maybe not totally.  This is my play on the
iPhone 4 antenna grip problem in 2010:
<http://802.11junk.com/jeffl/cellular/cell-test.htm
Steve Jobs was right that all phones have the antenna grip problem. He
just didn't mention that the iPhone 4 had it 10 times worse than the
others.

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How far worse?  How did you measure "reception"?  What were you
measuring?  Using wi-fi receive signal strength from an app or
counting "bars" isn't worth much.  These vary substantially between
devices and is affected by temperature.

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Yes of course.  Since I don't like Apple, every Apple is by definition
far worse than Android.  Or course, for a nominal bribe, I can reverse
the situation.

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Jeff lives on a fault.  Being honest improves my karma, and prevents
earthquakes from ruining my day.

In the past, I've offered you various ways of running a controlled
range (performance) test.  The next time you get your hands on a test
device, try it.  It's quite easy.

1.  You will need a reasonably fast computah running iperf ver 2,
iperf3, or jperf.  This turn the compoutah into an iperf server by
running just:
   iperf -s
The computah should be connected via an ethernet cable to the users
router.  Gigabit ethernet is nice for measuring maximum speeds, but
that's not what we're doing here.

2.  Next, you'll need a iperf client on the phone or tablet.  There
are iperf clients for most OS's.  Note that iperf2 and iperf3 are
quite different and not really compatible.  If the version is not
specified, it's probably iperf2.

Android:
<https://play.google.com/store/apps/details?id=net.he.networktools&hl=en
<http://networktools.he.net/
<https://play.google.com/store/apps/details?id=com.magicandroidapps.iperf&hl=en

IOS:
<https://itunes.apple.com/us/app/he.net-network-tools/id858241710?mt=8
<http://networktools.he.net/
<https://itunes.apple.com/us/app/iperf-network-bandwidth-measurement/id951598770?mt=8
<https://itunes.apple.com/us/app/iperf3-network-bandwidth-performance/id986846572?mt=8

PC, OS/X, Linux, etc:
<https://iperf.fr/iperf-download.php

Note that most Linux mutations ship with iperf2 and that iperf3 must
be installed.  You can have both iperf and iperf3 installed at the
same time:
<https://iperf.fr/iperf-download.php#more-recent

JAVA (runs on anything that groks Java and does pretty graphs):
<https://www.rarst.net/software/jperf/
<https://sourceforge.net/projects/iperf/files/
JPerf is iperf2 not 3.  Version 3 is for higher speed wireless.  Don't
mix versions.

Tutorials on iperf and jperf:
<http://openmaniak.com/iperf.php
<https://www.jamescoyle.net/how-to/574-testing-network-speed-with-iperf
<https://www.jamescoyle.net/cheat-sheets/581-iperf-cheat-sheet

I recommend the HE (Hurricane Electric) versions which will test
either IPv4 and IPv6.

YouTube video of a typical test:
<
https://www.youtube.com/watch?v=4qdKgHBO_Gc


Some notes I made from a talk on iperf and jperf:
<http://802.11junk.com/jeffl/FLUG-talk-2015-03-28/iperf3%20talk.htm

3.  Connect your test phone or tablet via wi-fi and just run a test to
see if it works.  If you're running Jperf, you should see something
like this:
<http://802.11junk.com/jeffl/FLUG-talk-2015-02-28/802.11gn%20direct.jpg
Note that the max speed is about 60 Mbits/sec.

If you insert a wireless repeater in between the wireless router and
the client, you get this mess:
<http://802.11junk.com/jeffl/FLUG-talk-2015-02-28/802.11gn%20through%20Netgear%20repeater.jpg
Note the drastic drop in maximum speed.  I'll save my rant against
mesh networks for another day.

4.  Now comes the big trick.  Temporarily change the speed of your
wireless router from "automatic" to a fixed speed and/or protocol. For
802.11g, that would be 54 Mbits/sec.  For faster protocols, it can be
faster.  If you have an 802.11ac wireless router, leave both 2.4 and
5GHz on.  However, if you're testing with a lesser protocol, enable
only one frequency band at a time, so that you know which one you're
testing.  I would initially do the test using 802.11g and 54Mbit/sec
because higher speeds and protocols allow for fallback, which will
produce odd results.

By fixing the speed and protocol, you're eliminating the ability of
the wireless router to slow down the wireless connection speed and
thus improve the range.  As you walk away from the wireless router,
instead of a general slowdown, you'll see an abrupt drop in speed,
possibly followed by a disconnect.  The typical 2.4GHz 802.11g system
will go about 10 meters before the speed drops abruptly.  Measure and
record this distance along with the test conditions (devices,
frequency, protocol, fixed speed, etc).

You'll find indoor testing to vary substantially, mostly depending on
reflections and wireless router antenna positions.  Outdoors works
better, but only if you don't have any interference.  Try to pick an
empty channel (good luck with that).

5.  If you're lazy and don't want to deal with servers and iperf, you
do something similar with just ping.  You still have to set a fixed
speed and protocol, but you don't get the pretty graphs and data. Just
continuously ping the wireless router.  At some point, the latency
will drastically increase, followed by 100% packet loss, and possibly
a disconnect.  This is not as precise as iperf because you're not
saturating the pipe with traffic, but probably good enough.

6.  That's all there is.  The "range" of a device, which is a
measurement of the overall radio design, antenna, internal noise,
packaging, orientation sensitivity, etc quality, should give you a
clue as to relative quality of the various test devices.  If
everything you test craps out at approximately the same range (using
the same speeds and protocols), then as far as I'm concerned, they're
all the same.  However, if you see substantial variations, then you
can legitimately claim that Apple and Android devices are different.

7.  Incidentally, you can also try it pointing iperf to a public
server instead of your own iperf server.  Note that you'll be
measuring the speed of your internet connection, not the speed of the
wireless.  I wouldn't do that for the range test.
Iperf public servers:
<https://iperf.fr/iperf-servers.php
Also, if you want to be sick, try running iperf over a cellular data
connection.

Just do it.  I didn't spend an hour writing all this so that you lean
back in your chair and deliver your "impressions" or "feelings".  Such
things as range can and should be tested.  If you need help, you know
where you can try to pry me out of my hole.

Good luck...


--  
Jeff Liebermann     jeffl@cruzio.com
150 Felker St #D    http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann     AE6KS    831-336-2558


Re: WiFi sensitivity question for Jeff Liebermann & anyone well versed in antennas
On Sat, 30 Jul 2016 17:49:59 -0700, Jeff Liebermann wrote:
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Interesting. Very interesting, as I have Apple and Android devices, and my  
WISP has dealt with them, and almost *every* home that complains about piss  
poor WiFi reception is an Apple home where I help out.

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Fair enough.


I have had the two iPads tested at the Apple Genius bar, and they passed  
"that" test, even though they both fail miserably at having the same WiFi  
reception as all four of my Android devices have.

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I *knew* you had tested Apple antennas in the past!
  "The worst phone I tested dropped the rx signal 16 times (-12dB). The  
iPhone 4 rx signal dropped 100 times (-20dB) to 288 times (-24.6dB) .  
That's a 6 to 18 times worse signal drop for the iPhone 4. Little wonder it  
drops calls. My guess(tm) is that something more than detuning the antenna  
is happening. I suspect that the receiver front end might be slightly  
regenerative, where touching the antenna kills the regeneration and the  
associated sensitivity."

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In all cases in "my" house, I had my Android devices on a flat surface  
within a foot of the iOS devices when the Android devices would easily  
connect home broadband router at the far fringes of the home, while the iOS  
devices failed to make any connection.

I had to solve the problem by setting up a spare WRT54G router as a wired  
extension (crawling under the house and cursing Apple the entire time), so,  
the fact that the WiFi reception of the iOS devices sucks compared to that  
of the Android devices caused me considerable effort.

In addition, as you know, I assist my small WISP in setting up customers  
and troubleshooting when they have WiFi problems. Almost invariably, the  
Apple-based customers are highly non technical, so, they call up with  
problems that aren't really the WISP's prerogative, such as the fact they  
can't connect to either his or their routers (he insists everyone have a  
router so he gives them one if they don't have their own).  

Almost always, if not always, I put their iDevices next to my Android  
device to test WiFi connectivity and signal strength at the distance that  
the customer complains.  

Even though the tools available to sniff WiFi issues on iOS devices are  
downright primitive, you "can" easily see that the Android devices  
"connect" to the router at distance while the iOS devices are oblivious of  
the router at the same distances.  

Working in the other direction, I start with the iOS device in one hand,  
and the Android device in the other hand, using the primitive iOS tools and  
the more sophisticated (aka modern) Android sniffing tools, so that I can  
see the BSSID and perceived signal strength (in case there are multiple  
SSIDs of the same name, as I have in my own setup), and almost always, if  
not always, the iOS devices *drop* the connection well before the Android  
devices do (I generally walk outside until the Android device drops the  
connection).

After having done this so many times, whenever we get a call, we ask if  
they're using Apple equipment, and, if they are, we know what's going on.

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While my grandkids play games almost exclusively on the iDevices, the main  
problem "I" have with Apple is that it's primitive in terms of being able  
to do useful things, e.g., WiFi reception sniffers on iOS are primitive in  
comparison to what's available on Android.
  
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Given the century-long cycles, you already had yours in 1989. Let someone  
else have their faults!
  
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Looks like iPerf is available on iOS & Android & Windows & Linux!
https://iperf.fr/iperf-download.php

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I don't have any fast computers - but just basic laptops.

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This is good that we an lay two mobile devices on a desk and run the same  
iPerf utility to check performance.
  
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I'd just pick one. Probably iPerf2 for compatibility.
  
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I'd stick with iPerf 2.
  
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Interesting that Mike Pennacchi set up a linux box running iperf -s.
Then he runs Android iperf -c to get 10.0.10.80 as the linux box.
Then he runs Android iperf for 60 seconds & gets 50Mbps throughput.

With iPerf, not only Android but even the primitive iOS phones can be  
turned into powerful network-troubleshooting tools!  

This is great information!
  
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You used iperf3, but I'd probably use iPerf 2 only because I want simple  
compatibility with iOS and Android, Windows, and Linux.

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Are the three graphs (purple, green, and blue) different access points?
Or are they different ports on the computer (1840, 1872, & 1860)?

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Thanks to you, I set up a *wired* extender out of my spare WRT54G router,  
as you had explained, long (long) ago, that the extender is faster, in  
effect, than the repeater - even though the repeater is easier to set up  
(but not easily set up on a WRT54G v5 due to lack of memory).

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I've never done this. I'll have to check how to set the speed on the  
Netgear WNDR2400 router and the Linksys WRT54G router. I'm sure the speed  
is currently set at defaults.

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Hmmmm....


Ah. That makes sense!

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Eureka! That's the test I need to run!

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That's a PERFECT test!
My hypothesis is that the iOS devices will drop in half the distance that  
the Android devices will drop - but that remains to be seen in the test.

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We're in the boonies. Empty channels aren't hard to find.
Especially in the 5MHz range.
  
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In general, for utilities, the limitation is that iTools don't allow  
powerful tools, but it seems, on iOS, apparently there is a simple ping app  
from MochaSoft:
https://itunes.apple.com/us/app/network-ping-lite/id289967115?mt=8

Android, as would be expected for a mature mobile operating system, has a  
bunch of usable ping utilities, e.g., StreamSoft makes:
https://play.google.com/store/apps/details?id=ua.com.streamsoft.pingtools&hl=en
  
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I would agree with you.

If the two devices under test crap out at the same time, then they're  
equivalent. If the Android device craps out at twice the distance of the  
iOS devices, then the hypothesis is supported.

Of course, I'd have to test multiple random devices to be sure of the data.

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I've already many times over seen substantial variations.
So, what remains is only a more rigid test, as you have proposed.
  
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Cellular is not in the cards; just WiFi.

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I will set up the iperf 2 on the various devices and test this out!

Re: WiFi sensitivity question for Jeff Liebermann & anyone well versed in antennas
Am 31.07.2016 um 04:59 schrieb Aardvarks:
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You will want to test different device orientations as well. Reception  
might (from my experience: does) differ depending on device orientation  
(e.g.: with the back facing in the AP direction, with the  
top/bottom/left/right sides facing the AP).

Additionally, reception will differ as well depending on how/where you  
put your hands (for an extreme example see the old iPhone4 Antennagate,  
where bridging the different antenna segments of the frame could lead to  
a dramatical decrease of signal strength), which hand you're using (a  
ring on one hand might influence the readings), whether there's a  
protective cover on the phone (and of which type, ...), ...

Obviously, you will need to test several devices for each device model  
(in order to rule out issues with a specific device), and different  
models altogether.

Lot's of influencing factors, that you want to take into consideration.

Best of luck,

Michael


Re: WiFi sensitivity question for Jeff Liebermann & anyone well versed in antennas
wrote:

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Wow.  I like that.  Not only are you more cynical than me, you also
have an excellent grasp of how to trash a good idea.  The problem with
your statements, all of which are correct, is that there is no
closure.  There are an infinite number of tests which "should" be
performed in order to produce accurate results.  Besides various
orientations and locations, such tests should be performed at
different temperatures, altitudes, positions of the moon, and using
all left handed people.  It doesn't matter how carefully one sets up
an RF test, there are always missing factors that someone suggests
might have an effect.  Admittedly, sometimes it does.  For example, I
participated in one parking lot test where all the 2.4Ghz wi-fi stuff
was placed about 3ft above ground level.  When I pointed out that at
3ft, the path was well within the Fresnel zone:
<http://www.proxim.com/products/knowledge-center/calculations/calculations-fresnel-clearance-zone
and should be elevated in order to improve accuracy, the engineer in
charge was initially reluctant to change, even though he knew I was
right.  To his credit, he raised the antennas as high as possible, and
the result began to look more consistent and realistic.

As you note, multiple studies tend to offer new insights into a test,
which often disprove previous claims.  The trick is to have a large
number of people performing a test, not necessarily in exactly the
same manner.  It doesn't take long for a pattern to appear from which
additional conclusions can be drawn.  That's exactly what happened
with cold fusion, where a few claimed to have duplicated the original
results, but far more failed.

So, we now have a comparison between Apple and Android.  Both devices
and wireless routers are sufficiently common that anyone can perform a
suitable performance and range test.  Claims have been made and all
that's needed are a few brave people to extract their faces from their
retina monitor and convince first themselves, and possibly others of
the relative merits of Apple versus Android.

--  
Jeff Liebermann     jeffl@cruzio.com
150 Felker St #D    http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann     AE6KS    831-336-2558

Re: WiFi sensitivity question for Jeff Liebermann & anyone well versed in antennas
wrote:

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I've had four iPhones  the original, 3G, 4S and 6.  Never had a
dropped connection.  But then I rarely use it while in my microwave.

Re: WiFi sensitivity question for Jeff Liebermann & anyone well versed in antennas

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That's quite true.  The RF pattern produced by a cell phone is
tailored primarily to meet SAR (specific absorption rate)
specifications.  There's very little RF emitted in the direction of
the head, while much more out the back.  Oddly, the peak for
smartphones is often straight down, where there are fewer obstructions
and the users hand is not likely to be holding the phone.  Try
pointing the bottom of the phone at the nearest cell site and see if
the signal improves.  It does on my Moto G phone.

Measuring the antenna patterns is not easy, but possible.  All you
need is a $100 million anechoic RF chamber:
<
https://www.youtube.com/watch?v=x86tiU3fkSk
(1:41)

and a huge pile of RF test equipment.  I do my best using junk, but it
doesn't compare to having the real goodies.

Second best is to model the phone with an NEC4 modeling program.
<https://www.google.com/search?tbm=isch&q=antenna+pattern+cell+phone
Those are the colorful 3D patterns.  I do my best with 4NEC2 free
software.
<http://802.11junk.com/jeffl/antennas/

What you'll probably find is that the local RF environment (reflectors
and absorbers) has a much bigger effect on RF performance than the
cell phone antenna pattern.  Both will cause variations in signal
strength, often in odd ways.  The best I can do is wave the phone
around and record the highest reading or the average reading.  Neither
is perfect, but the effort necessary to obtain a good 3D picture of
the phone is just too much work.

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In this case, the issue is whether there is a difference in range and
performance (speed) between Apple wi-fi devices, and Android wi-fi
devices.  This can be tested with both types of devices side-by-side
and connecting to the same wireless router.  I previously posted 2
good ways to perform the test, which so far nobody seems to have
performed.  Also, nobody has asked me to perform any tests in order to
settle the issue, so I'm doing what I do best, which is nothing.

--  
Jeff Liebermann     jeffl@cruzio.com
150 Felker St #D    http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann     AE6KS    831-336-2558


Re: WiFi sensitivity question for Jeff Liebermann & anyone well versed in antennas
Am 02.08.2016 um 01:02 schrieb Jeff Liebermann:
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The primary directions for mobile network antennas and WiFi antennas may  
be different, so one would have to test them independently...

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Side-by-side (taking this literally) might be yet another influencing  
factor, where one device (might) severely interfere with the other.  
Additionally (forgot to mention that in my previous post) there  
shouldn't be anybody running around inside the test area (which is  
larger than just the direct line of sight between the device(s) and the  
AP), no cars should be passing in the vicinity, there should be no  
neighboring WiFi networks even at the horizon, ...

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I won't do the tests, for several reasons:

- I don't have any Android device available, least several different ones.
- Where I live I can easily and at any time find several other WiFi  
networks.
- I wouldn't have enough open range (without reflections from other  
houses, passings cars, heck there are even electrified railroad tracks  
at about 500m distance).
- ...

Way too bad conditions for performing such a test.

Best regards,

Michael

Re: WiFi sensitivity question for Jeff Liebermann & anyone well versed in antennas

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True.  However, unless you use an RF anechoic chamber, the influences
of the room environment will have a bigger influence than the antenna
patterns.  Reflectors and absorbers will ruin any test, unless you're
interested in performing a "real world" type of test, which is what
this range test might be considered.  For example:
<http://www.smallnetbuilder.com
does their benchmarks indoors, with plenty of walls and furniture to
get in the way.  I think it's part of Tim Higgins house, but I'm not
sure:
<http://www.smallnetbuilder.com/wireless/wireless-features/32512-does-an-ac-router-improve-n-device-performance
The RF environment is far from perfect, but it's identical for each
router being tested, which the point of the test:

More on how they run their tests:
<http://www.smallnetbuilder.com/wireless/wireless-howto/32478-how-we-test-wireless-products-revison-8
<http://www.smallnetbuilder.com/wireless/wireless-howto/32993-how-we-test-wireless-products-revision-9
<http://www.smallnetbuilder.com/wireless/wireless-howto/32944-how-we-test-mu-mimo
and even more:
<http://www.smallnetbuilder.com/tags/how-we-test

The overall results are rather interesting (to me).  Different
routers, which use the same chipset and roughly the same antennas,
produce substantially different performance results.  I don't have
time to speculate on why, but let's just say that there are is a large
list of uncontrolled factors that have an effect on the measurements.
One can eliminate a fair number with a $100 million RF anechoic
chamber, but that's a bit beyond my present means.

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True.  However, if a wireless client is associated with an access
point, but not passing any traffic other than the usual beacons and
broadcasts, there is very little traffic that might constitute
interference.  Offhand, my guess(tm) is about a 1/100 duty cycle. Were
any of these packets to collide with traffic from a nearby wireless
device, the error would be about 1% from the collision.  

However, for the range test, this will have no effect because we're
not trying to squeeze as many packets as possible through a pipe.
We're trying to determine the range at which it is no longer possible
to pass packets or where the connection becomes unstable.  At worst,
packet collisions will "blurr" the results somewhat.  I don't consider
proximity to be a problem.

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Part of the range test is take the tablet or iphone and walk away from
the wireless router, noting the range at which traffic ceases.
Presumably, one would need to hold the device to do that.  At the
frequencies involved, placing the device on top of a cardboard box
when carrying it will minimize proximity effects and antenna detuning,
while still allowing one monitor the device.  It's far from perfect,
but methinks good enough.

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Borrow one or invite your friends to the test.  Or, are all your
friends Apple users?  What a horrible thought.

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Not a problem.  You're not trying to maximize throughput, just
determine how far you can operate before it quits.  You can do that
with ping, which hogs very little bandwidth, and will not interfere
with the neighbors streaming wireless connection.

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I think you'll find that at 802.11g speeds, with the wireless fixed at
54Mbits/sec, you'll get about 30 meters range.  The transition between
working and dead will be quite abrupt, usually within a meter or two.
If you find a straight line path that's about 50 meters long, you
should be ok.

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It doesn't matter.  We're comparing two devices, not producing an
absolute measurement.  Absolute measurements would be nice, so we
could compare your results with mine and others, but that's not going
to happen without an extremely well controlled environment.  However,
when comparing two devices, the conditions are identical, and
therefore the comparison is quite valid.  

You probably spent more time finding excuses to not run the test than
it would take to actually perform it.  Thanks for at least thinking
about the problems involved.


--  
Jeff Liebermann     jeffl@cruzio.com
150 Felker St #D    http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann     AE6KS    831-336-2558

Re: WiFi sensitivity question for Jeff Liebermann & anyone well versed in antennas
Am 02.08.2016 um 18:40 schrieb Jeff Liebermann:
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In an open-field scenario (as Aardvark claims to have) that should not  
be a problem - while the main antenna orientation might still have an  
influence. Especially if by chance the main antenna direction is covered  
by the holding hand...

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Agreed.


Not only yours... ;-)

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I was not referring to interfering traffic from the multiple devices,  
but actually about RF interference which might (or might not) influence  
the signal strength as received by the chips inside the phone. Basically  
increasing 'background noise'. And this factor does not have to be  
symmetric, as it will depend on antenna design, circuit board design,  
case design (and materials), ...

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Proximity (of the several devices used for measurements) might be a  
problem. How can you rule that out?

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Agreed.


Yes, they are. And that's not at all a horrible thought (unless you're  
thinking like Aardvarks).

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It's not a problem of bandwidth. But a matter of RF interference, and  
that might change any second, e.g. depending on the current usage of the  
other networks. I can control the usage of mine, but not the usage of  
the other ones. And as the frequency band is crowded on any channel, I  
don't stand a chance of finding an unused set of channels (for 2.4GHz  
I'd need three neighboring channels to be sufficiently safe, for 5GHz  
I'd have to look that figure up).

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And that's already where I would fail.

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In general that's true, however how good is any result if you can't rule  
out at least major influencing factors (beyond the ones to be tested)?

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I did not spend more than one second on any reasons why I won't execute  
the test, as the answer is simple: It's Aardvarks' claim, and the past  
'discussions' with him here have given ample proof that he won't even  
accept the best founded test results. If they're not supporting his  
view, that is.

So I resort to 'his claim - his proof'. And as he always claims that he  
proves everything he says (something already found to be not true time  
after time), I won't even start going down this path.

There are some more reasons I could bring up, but I'll leave it for now.

Best regards,

Michael


Re: WiFi sensitivity question for Jeff Liebermann & anyone well versed in antennas
On Sun, 31 Jul 2016 02:59:24 -0000 (UTC), Aardvarks

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I don't have a proper 802.11 tester, but can make some fairly good BER
(bit error rate) and signal level tests on my messy workbench.  Yeah,
it's all antiques but it's probably better than what you'll find at
the Genius Bar:
<http://802.11junk.com/jeffl/pics/home/slides/test-equip-mess.html
Mostly, I find that RFI/EMI from the computah section of a smart gizmo
causes most of the loss of wi-fi reception problems.  For example, my
Droid X and X2 would show reduced sensitivity when the display
backlighting was on full compared to when it was dim.  My guess(tm) is
that most of the wi-fi radios are quite good, but in proximity of the
computah noise generator, don't do as well.  How Apple or Android
compare, I don't know.

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Well, that's a fairly good side by side comparison.  However, it might
not be the radios.  One of my customers is all Apple.  They must have
one of everything, although wisely, they never buy the latest devices.
I had problems with range at their house.  My Chrombook, Nexus 7
tablet, and Moto G phone were also having range problem.  I eventually
found a neighbor with Roku 2 and 3 boxes streaming away furiously
24x7, with both located near facing windows.  I convinced the neighbor
to let me connect the Roku boxes with ethernet cable (3ft and 6ft
away), which eliminated the problem.  Range was then dramatically
improved.

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You'll get no sympathy from me.  I do that all the time.  However, my
days of crawling under houses are largely over thanks to health
issues.  I was pulling wires and installing wall jacks last week for
about a day, and still haven't recovered.  Maybe I'll learn to like
power line connected wireless repeaters instead.

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Ok, the first step to solving a problem is to blame someone.  In this
case Apple.  I tend to allow other options, such as junk routers and
interference.  I carry a WiSpy 2.4Ghz spectrum analyzer, that isn't
limited to seeing wi-fi devices.  Amazing what I find out there.
<http://www.metageek.com
<http://www.metageek.com/products/wi-spy/index-3.html

However, I did have problems with the older Apple Airport wireless
routers.  Even the Apple products would not stay connected.  Almost
anything could connect, but didn't stay connected.  Streaming was the
big problem, where it would disconnect abruptly and without much
provocation.  I usually solved it by temporarily replacing the router
with a Linksys equivalent.  Current favorite is a Linksys EA2700.
Range is not so good because it's a lower power device than most.  I
don't care because if a customer want's to go through walls, I just
sell them another EA2700 router.

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You're being generous.  I use my Android phone and tablet as if they
were test and diagnostic equipment.  I don't know what Apple allows,
but as I recall from using an iPhone 3G for a while, it's not much.  I
had to jailbreak my 3G to install something useful.  Here's the latest
version:
<https://www.adriangranados.com/apps/ios-wifi-explorer

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If you recall, I offered exactly the same song and dance to you about
2 years ago.  There were versions for just about every OS available at
the time, but I must admit, were somewhat crude.  So, this time,
please run the tests, and you can thank me later.

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Sorry.  You'll need a fairly fast computah if you're going to do tests
with gigabit ethernet or 802.11ac.  The idea is to make sure that
everything involved is faster than the wi-fi link.  You'll also need
to use iperf3 to get accurate numbers for the higher speeds.  However,
we're not interested in how fast you can go.  We're looking for when
the data no longer is flowing smoothly or when it drops out.  You can
get away with almost anything that looks like a computah and will run
iperf.  I have an microSD card that I use on a Raspberry Pi 2 box as a
quick an dirty iperf server.  It won't do gigabit, but I usually don't
need such test speeds.

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Yep, but always have a reference machine handy that you know for sure
that runs fast and well.  When everything you test runs badly, and you
don't know if the problem is with everything you're testing, or with
the server, router, network, interference, etc, it's always nice to
have a tie breaker.

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Try jperf for starters.  It's the easiest to use and includes the
iperf2 binaries in the package buried in a subdirectory.  If you want
to do speed testing, switch to iperf3.

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Yep.



It was 3 separate runs of the program.  The numbers are NOT port
numbers.  I was doing some fiddling with the setup and wanted to see
what produced the best throughput.

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We shall soon see.

Good luck.

--  
Jeff Liebermann     jeffl@cruzio.com
150 Felker St #D    http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann     AE6KS    831-336-2558

Re: WiFi sensitivity question for Jeff Liebermann & anyone well versed in antennas

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the iphone 4 was not 10x worse.  

it was comparable to other phones and in many cases, those other phones
were substantially worse, even dropping to no service, something the
iphone 4 didn't do.

palm pre drops to no service:
<
https://www.youtube.com/watch?v=zft3-Lwh2bo


droid incredible drops to no service:
<
https://www.youtube.com/watch?v=c4zbQ3f7H0U


droid 2 had serious issues:
<https://techcrunch.com/2010/08/13/uh-oh-early-droid-2-units-having-sign
al-issues/>
  The signal on one of the two units we received is all over the board,
  dipping from full signal down to nearly none whilst sitting in the

  says that four out of four of their units show endlessly fluctuating

  bad luck with his, as well. Thats 6 review units, all showing signs
  of signal woes. Not a good sign.

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that explains everything.



Re: WiFi sensitivity question for Jeff Liebermann & anyone well versed in antennas
wrote:

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Well, you're certainly entitled to an opinion.  Personally, I prefer
opinions based on repeatable tests, measurements, numerical results,
and calculations.  However, I'll accept your assertion for what it's
worth.  However, I did make one mistake.  The iphone wasn't 10 times
worse, but more like 6 to 18 times.  Citing my web page:
<http://802.11junk.com/jeffl/cellular/cell-test.htm
  "The worst phone I tested dropped the rx signal 16 times  
  (-12dB). The iPhone 4 rx signal dropped 100 times (-20dB)  
  to 288 times (-24.6dB). That's a 6 to 18 times worse signal  
  drop for the iPhone 4... "

One problem was that I didn't have access to an iphone 4 at the time
of the controversy.  None of my friends would trust me to jailbreak
their phone just so I could get a signal strength reading in dBm
instead of "bars".  So, I had to use the test results from the
Anantech article.  A friend has an iPhone 4 that he's not using, so I
could probably repeat my test given sufficient inspiration.

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Yeah, that was cute.  Initially, Verizon phones would stay connected
for quite a while after total loss of signal.  I put a VZW iphone 4 in
a shielded box during a call, waited up to about 2 minutes, and was
able to resume the call uninterrupted.  Nicely done by VZW.  However,
AT&T was initially a different story.  I did the same test with an
AT&T phone (not an iPhone) and found that it would disconnect after
only a few seconds.  About a month later, after AT&T announced that
they had "upgraded" their network to match capabilities of the new
iPhone, it would also stay connected after 2 minutes of carrier loss.

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I have an old VZW Palm Pre somewhere in the office.  I'll try it on
Mon or Tues.  

Interesting test.  He's in a weak signal area.  Grabbing the phone
drops the signal level enough to produce a loss of connection.  That's
not surprising.  It would be more interesting if he put the phone in
the Field Test Mode to see how much the signal drops.  If the phone is
right at the bitter edge of disconnecting, and the signal drops a few
dB, I would expect it to umm.... disconnect.  Note that all the phones
used in my test showed about a 9 dB drop in receive signal from a
death grip, which would produce exactly the same results in a weak
signal area as the Palm Pre.

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This is almost as bad as the Pre test.  Instead of being in a one bar
weak signal area, he's got 2 bars.  I'm not so sure that the HTC Droid
Inedible (VZW only) has the antenna at the bottom.  I tried to find it
on the iFixit teardown at:
<https://www.ifixit.com/Teardown/HTC+Droid+Incredible+Teardown/42422
and couldn't find it.  Other users are also having problems:
"FIX HTC INCREDIBLE S RECEPTION ANTENNA ISSUES"
<
https://www.youtube.com/watch?v=QHIdl1qrdkc
(6:42)

Fast forward to 4:35 to see what he's done.
In other words, not the best phone or antenna system.  Of course, the
author doesn't care about potential SAR problem.

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That's just a crappy phone.  It could be anything from bad design, bad
implementation, bad parts, bad metering, or just having a bad day.  I
assume that this has something to do with your defense of Apple, but I
lack the wisdom to make the connection.

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Even honesty has a price tag.

--  
Jeff Liebermann     jeffl@cruzio.com
150 Felker St #D    http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann     AE6KS    831-336-2558


Re: WiFi sensitivity question for Jeff Liebermann & anyone well versed in antennas
On Sat, 30 Jul 2016 20:44:02 -0700, Jeff Liebermann wrote:

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Jeff,
This nospam guy is actually one of the smarter ones here, along with Rod
Speed and the smartest guy here, who is David Empson. The problem though,
with nospam, is that his only playbook is verbatim what Apple Marketing
feeds him. He has no other repertoire.

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Where, for others' benefit, 9 decibels is 3db times 3 which is 1/2 times
1/2 times 1/2 the signal strength, which is 0.125 the original signal
strength (or around 1/8th the original signal strength if I did the math
correctly).

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Jeff - you have to understand that nospam thinks *exactly* like Apple
Marketing thinks. Thousands of times, he finds the absolute worst example
he can find in Android land, to compare with Apple.

For example, he tries to compare $50 Android phones to $800 Apple phones,
and then says that the Android phones stink. Or, he picks the absolutely
most expensive Android phone he can find on the planet, to compare with the
iPhone, and says conclusively that iPhones cost exactly the same as Android
phones.

In fact, I have a recent thread where I compare PERFORMANCE of a $300
Android phone to the iPhone 6, and he pooh poos that because I didn't use
the absolutely most expensive Android phones on the planet to make my
performance tests.

At first you wonder why he thinks like Apple Marketing, but then you just
get used to it once you understand that:
a. He buys only on cachet (so anything bad about Apple is a threat)
b. He buys based on fear (so anything outside the walled garden is scary)
c. He can only think of the single solution Apple Marketing gives him

Once you realize *everything* he says is imbued by those three tenets, then
you realize why he sounds exactly like Apple Marketing sounds.

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The funny thing about nospam, Jeff, is that you can be honest with him, but
he will *never* be honest with you.  

If you (or I) have a favorable datum about Android versus iOS, we speak it
out, and weigh it proportionately. Nospam is the consummate Apple marketing
guy. He is so afraid of facts, that he will *never* speak anything out
against Apple, even though he surely must be aware of the huge flaws.

At first I couldn't understand his duplicity. I thought it was stupidity.
But he's duplicitous because of the three things I said:
a. He's *protecting* his purchase decision (at all costs!)
b. He's *protecting* against anything *outside* the walled garden
c. He's *protecting* against the one-button-mouse mentality that Apple
Marketing has and always has had.

So nospam will *never* see both sides of the coin.
Never.  
And even if he did - he'd never admit it.

On the other hand, you:
a. Buy by price:performance so performance is just a set of numbers which
is nothing to fear
b. Buy what works for you with the equipment you use, and not necessarily
only one brand of equipment
c. Try every solution that makes sense, and not just the
single-button-mouse solution that one manufacturers' marketing team
specifies

Until you understand these three things, you'll never understand why nospam
writes what he writes (nor most of the other Apple Aficianados).

a. They care only about style
b. They are fearful of anything not told to them by Apple Marketing
c. They can only think of one-button-mouse style solutions proposed by
Apple Marketing (which only work inside the walled garden).

Anything outside those three areas, they "just give up".
In fact, they're so used to "just giving up", that it's not funny in that
is so different than your mental makeup.

Re: WiFi sensitivity question for Jeff Liebermann & anyone well versed in antennas
On Sun, 31 Jul 2016 22:26:43 -0000 (UTC), Aardvarks

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I don't care.  I don't pass judgment upon the writers of usenet
articles, only on the content of their articles.  The author could be
evil incarnate, and I would still take their comments seriously.  I
also value their opinions based solely on their ability to
substantiate them.  In other words, no numbers, no tests, or no
references, and it goes to recycling.

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Not a problem.  Everyone lies, but that's ok because nobody listens.

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Ah, my favorite topic... me.

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Wrong.  I hardly buy anything new for myself.  I buy plenty for my
customers, but for myself, I buy used, refurbished, and recycled
hardware.  Most of my computers were machines replaced by my customers
in an upgrade.  Almost nothing I own was purchased new.  Performance
(numbers) is way down the list because it is cheaper to tolerate
mediocrity and do battle with the bleeding edge of technology.

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Sorta.  I have a few brands that I prefer.  However, even the best
companies have produced defective products and probably will continue
to do so erratically.  There's also quite a bit of private labeling of
other companies products.  I do tend to favor manufacturers with which
I have a working relationship, or know someone on the inside, as that
makes it easier to deal with surprises and problems.

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Sorta.  My customers also was ease of use.  That makes self
configuring devices, wizards, and one-button connect features
attractive.  For myself, they just get in the way of diving into the
menus and making it do what I want.  While not a single button
solution, I really like the Chromebook philosophy of letting Google do
everything.  I can literally setup a Chromebook in minutes, and have
it ready to use without the hassles of endless updates, virus scans,
malware scans, bloatware, etc.  Customers want easy and so do I
(because we're all fundamentally lazy).

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Nope.  They throw money at the problem.  Applecare is all about buying
failure insurance.  Out of warranty repairs are very expensive.  Flat
rate exchange instead of repair is all about inspiring a premature
upgrade.  Some parts are unobtainable.  When I fix a PC or PC laptop,
I can get cheap parts from the cannibals on eBay.  I can do the same
with Apple parts, but not for current model products.

Incidentally, in Dec 2009, I did a price comparison between various
Apple products and the closest equivalent Dell products:
<http://802.11junk.com/jeffl/crud/Mac-vs-PC.xls
The 13" MacBook was a bargain at the time, but all the other Apple
products were about twice the price of Dell.  Prices do not include
shipping, Applecare, or Dell extended service contracts.  I haven't
checked, but I think the situation is much the same today.

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Nope, they don't give up.  The average Apple product user assumes that
since Apple products are nearly perfect, whatever is wrong must be
something they had done.  Although I don't do much work on Apple
products, the few that drift into my office generally start out by
asking if it was anything that they had done wrong to cause the
problem.  There's a related problem where users are afraid to ask for
help because they assume that Apple makes things so easy, that if they
have a problem doing something, it must be their inability to
understand, rather than something Apple did wrong.

Apple... making easy things easier, and difficult things impossible.

--  
Jeff Liebermann     jeffl@cruzio.com
150 Felker St #D    http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann     AE6KS    831-336-2558

Re: WiFi sensitivity question for Jeff Liebermann & anyone well versed in antennas

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in some cases, apple is much cheaper.

for instance, there's nothing comes close to the retina imac 5k.

dell sells a similar 5k display *without* a computer for roughly what
apple sells the entire imac, which now has a wide-gamut display. not
only that, but it's expected to be updated in about a month or so.

Re: WiFi sensitivity question for Jeff Liebermann & anyone well versed in antennas
wrote:

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With all due respect, your unsubstantiated opinion does not do much
for me.  An example of equivalent PC and Apple products would be more
useful than your astute pontification.  Also, you seem to have an
aversion to supplying numbers.  A few of these would also improve your
credibility.

It was quite difficult to do the Dec 2009 comparison.  I was
recovering at home from surgery and was still somewhat drugged.  It
took me all day to nail down the details.  Even so, there are
differences between the Dell and Apple products in CPU speeds, memory
types, Firewire ports, and included accessories such as the mouse and
keyboard, which are options on Apple products but generally included
with Dell products.  Even with these differences, the ratio was still
about 1:2, except for the 13" MacBook.

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Is it really necessary that I have to do all the research?  All that's
necessary is for you to include a URL pointing to the two computers
and displays with prices.  Ok, I'll do the grunt work this time for
you and see if you're right.

I presume you mean the Apple 27" Retina 5K iMac computer.
<http://www.apple.com/imac/specs/
The screen is 5120 x 2880.
B&H has it for $1,900.
<http://www.bhphotovideo.com/c/product/1190403-REG/apple_mk472ll_a_27_imac_with_retina.html

I'll also assume that you're referring to the Dell XPS 27 Touch
All-In-One Desktop:
<http://www.dell.com/en-us/shop/productdetails/xps-27-2720-aio?stp=1
The screen is 2560 X 1440 or 1/4th that of the Apple display.
Prices vary from $1,700 to $2,700.

So, you're correct that Apple is indeed cheaper than Dell for roughly
equivalent computers and with a better built-in monitor.  Apparently,
some things have changed at Apple in the last 7 years.  I'll try to be
more careful when making price comparisons in the future.  I'll
probably update the spreadsheet as time permits.

Of course, this has nothing to do with any alleged wi-fi range
differences between Apple and Android products, which was the original
topic of this discussion.

--  
Jeff Liebermann     jeffl@cruzio.com
150 Felker St #D    http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann     AE6KS    831-336-2558

Re: WiFi sensitivity question for Jeff Liebermann & anyone well versed in antennas
On Sun, 31 Jul 2016 18:52:15 -0700, Jeff Liebermann wrote:

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Jeff.
That is the understatement of the year!

Re: WiFi sensitivity question for Jeff Liebermann & anyone well versed in antennas

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i substantiated it.

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useful to whom and for what task?

for some tasks, apple is the *only* choice. for others, windows is the
only choice. for most tasks, things are fairly close, but mac users are
generally more productive.

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i did supply numbers.

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you neglected a few differences, such as that mac os x is equivalent to
windows ultimate, not home.

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i assumed someone familiar with product pricing would know the status
quo.

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that's the middle model, but you can always configure to order.

$1799 for the base model:
<http://www.apple.com/shop/buy-mac/imac

and as i said, the imac is due for an update, expected in a month or
so, which means the above specs are about to change.  

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you assume wrong.

i specifically said the dell 5k display, which has the same 5120 x 2880
resolution and is $2k msrp:  
<http://accessories.us.dell.com/sna/productdetail.aspx?c=us&l=en&s=bsd&c
s=04&sku=up275k3>

that display was originally $2500, but then apple came out with the
imac 5k and dell had to cut its price.

street price is $1500ish these days, except that's only the display.  

you still need a computer that can drive that 5k display, which means a
dual video card and dual cables because one single displayport
currently can't support 5k.

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ok.


there aren't any significant differences in normal everyday use.  

he's trolling.

Re: WiFi sensitivity question for Jeff Liebermann & anyone well versed in antennas
wrote:

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No, you didn't.  You did in your previous posting, but only after I
guessed wrong as to what you were comparing.

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Actually, I'm not familiar with current retail PC or Mac pricing.  I
don't buy machines for my customers very often.  Prices change so
often that I have requote bids several times before the actual
purchase.  If I need prices, I get them at as near to the time of
purchase as possible.

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Sorry, but I thought you were comparing the price of equivalent
computers with build in displays, not comparing an Apple all in one
iMac, with a component system from Dell.  Your point about pricing is
still correct, but it would be helpful if you would be more specific
about what you're comparing.

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Prove it.  I supplied two very easy methods where you can test that
assertion using commonly available software (iperf and jperf) that
will run on most any device.  I can run the test for you if you can't
seem to load one program on your Mac desktop or laptop, change one
setting in your router, and load one lousy app on your tablet.
However, I don't see why I should run it for you.  I suspect that you
would not accept my results and conclusions as you did in my iPhone 4
death grip test.  The problem is that you don't really know for sure
what will happen.  Well, neither do I.  I've run the test many times,
but never side by side comparing the range for various client devices.
It's always been to optimize something in the router, usually for
highest throughput, not for maximizing range.

Quoted text here. Click to load it

So am I.  Sometimes trolling is useful.  I'm tired of unsubstantiated
assertions from all sides.  Time to test the various claims.

--  
Jeff Liebermann     jeffl@cruzio.com
150 Felker St #D    http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann     AE6KS    831-336-2558

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