Digest for sci.electronics.repair@googlegroups.com - 21 updates in 4 topics

nospam <nospam@nospam.invalid>: Aug 01 05:04PM -0400

In article <a9etpbtc0roj7ofbmsu8b9gki8f1u9phf0@4ax.com>, Jeff
> 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.
 
find a 5k all in one for comparison.
 
the imac 5k first came out 2 years ago and there *still* isn't anything
to match, so components is all that's possible.
 
there are some pc all in ones but they're not 5k displays which means
there's even more of a price advantage to the mac.
 
> 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.
 
that's not normal use.
 
normal use is connecting to wifi networks (public or private) and doing
normal everyday tasks, such as surfing the net, skype, checking email,
downloading new apps, etc. it's not running benchmarks and geeking out
over numbers.
 
i used to use my iphone 4 in a *wide* variety of places, from at home
(fairly strong signal) to airports & hotels (often weak and overcrowded
signals) and never had any problem with wifi or cellular.
 
> >he's trolling.
 
> So am I. Sometimes trolling is useful. I'm tired of unsubstantiated
> assertions from all sides. Time to test the various claims.
 
discussion is useful, not trolling.
Aardvarks <aardvarks@a.b.c.com>: Aug 01 09:44PM

On Mon, 01 Aug 2016 02:13:11 -0400, nospam wrote:
 
> and for that subsidy, google gets to track and data mine you, even
> though you think you're avoiding it. you're not.
 
You don't use any Google apps on that iOS device?
Aardvarks <aardvarks@a.b.c.com>: Aug 01 09:49PM

On Mon, 01 Aug 2016 02:13:11 -0400, nospam wrote:
 
> and for that subsidy, google gets to track and data mine you, even
> though you think you're avoiding it. you're not.
 
Without a Google ID, all it has is an advertising ID, which I switch
randomly, and which Google *says* they don't maintain the connection.
 
I don't log into *any* Google apps, as you know.
 
Since my system is well organized, I keep a duplicate folder of *just*
Google Apps, where every one is logged out of (and almost none are used
anyway, except maybe Google Maps). I have the history turned off if I'm
forced to log into an app, but I can't think of any app that you have to
log into other than Gmail, which is a different beast altogether, and,
which has the same issues on iOS anyway.
 
As you know, I also have my SSID tracking turned off, so that I'm not
spying on my self and my neighbors.
 
Likewise, I have all app connection to my location turned off, and no app
is allowed to use my location unless I expressly turn the app location
ability back on with App Ops Starter. And you have that same issue too on
iOS anyway, so, nothing is different there.
 
So, where, may I ask, is Google spying on me on Android that they're not
also spying on you in iOS?
Aardvarks <aardvarks@a.b.c.com>: Aug 01 09:51PM

On Sun, 31 Jul 2016 18:52:15 -0700, Jeff Liebermann wrote:
 
> Also, you seem to have an
> aversion to supplying numbers.
> A few of these would also improve your credibility.
 
Jeff.
That is the understatement of the year!
nospam <nospam@nospam.invalid>: Aug 01 05:52PM -0400

In article <nnog5r$55e$1@news.mixmin.net>, Aardvarks
> > though you think you're avoiding it. you're not.
 
> Without a Google ID, all it has is an advertising ID, which I switch
> randomly, and which Google *says* they don't maintain the connection.
 
it has more than that.
nospam <nospam@nospam.invalid>: Aug 01 05:52PM -0400

In article <nnofsa$4hc$1@news.mixmin.net>, Aardvarks
 
> > and for that subsidy, google gets to track and data mine you, even
> > though you think you're avoiding it. you're not.
 
> You don't use any Google apps on that iOS device?
 
don't change the topic.
Aardvarks <aardvarks@a.b.c.com>: Aug 01 10:01PM

On Mon, 01 Aug 2016 17:52:20 -0400, nospam wrote:
 
>> Without a Google ID, all it has is an advertising ID, which I switch
>> randomly, and which Google *says* they don't maintain the connection.
 
> it has more than that.
 
Like what?
Jeff Liebermann <jeffl@cruzio.com>: Aug 01 03:43PM -0700

On Mon, 01 Aug 2016 17:04:05 -0400, nospam <nospam@nospam.invalid>
wrote:
 
>that's not normal use.
 
Right. Instead of numbers that are useful for comparing performance,
we might have "it feels fast" or perhaps "it does what I need, which
is good enough". I used to do battle with such nonsense when dealing
with wireless product design. My standard answer was to suggest that
perhaps we need more realistic metrics, test conditions, procedures,
and environments, not vague impressions or "mean opinion scores".
 
>normal everyday tasks, such as surfing the net, skype, checking email,
>downloading new apps, etc. it's not running benchmarks and geeking out
>over numbers.
 
The nice thing about performance tests and benchmarks is that under
real world conditions, you're NOT going to get any better performance
than what is achieved by the performance testing. In other words, it
puts a ceiling on what to expect with your real world tests. Testing
at maximum speeds also tends to expose anomalies that would not
necessarily appear using a real world test. Of course, in the real
world, products that advertise big numbers tend to sell better than
products advertising the lesser real world numbers, which makes
companies prefer benchmarking. It's also rather difficult to compare
products tested under different real world conditions. Many real
world tests are difficult or impossible to reproduce and often produce
different numbers.
 
>i used to use my iphone 4 in a *wide* variety of places, from at home
>(fairly strong signal) to airports & hotels (often weak and overcrowded
>signals) and never had any problem with wifi or cellular.
 
Duly noted. Have you tried loading iperf or jperf and run a not so
real world test yet?
 
--
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
nospam <nospam@nospam.invalid>: Aug 01 06:47PM -0400

In article <nnogs9$6m6$1@news.mixmin.net>, Aardvarks
> >> randomly, and which Google *says* they don't maintain the connection.
 
> > it has more than that.
 
> Like what?
 
you've been told several times before.
Jeff Liebermann <jeffl@cruzio.com>: Aug 01 04:02PM -0700

>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).
 
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.
 
>(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.
 
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
avagadro7@gmail.com: Aug 01 05:39PM -0700

No Vista ?
 
 
find a cell tower with a straight desert highway stretching off from tower base.
 
drive away n check reception speeds n bytes captured.
Jeff Liebermann <jeffl@cruzio.com>: Aug 01 09:54PM -0700


>find a cell tower with a straight desert highway stretching off from tower base.
>drive away n check reception speeds n bytes captured.
 
Please re-read the original comments by Aardvarks.
<https://groups.google.com/forum/?hl=en#!original/alt.internet.wireless/mr9elO6AFnU/TNZOls9aAwAJ>
This is about wi-fi, not cellular.
 
 
--
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
Michael Eyd <invalid@eyd.de>: Aug 02 09:03AM +0200

Am 02.08.2016 um 01:02 schrieb Jeff Liebermann:
> 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.
 
The primary directions for mobile network antennas and WiFi antennas may
be different, so one would have to test them independently...
 
 
> 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
 
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, ...
 
> 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.
 
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
avagadro7@gmail.com: Aug 02 06:11AM -0700

On Tuesday, August 2, 2016 at 12:54:23 AM UTC-4, Jeff Liebermann wrote:
> 150 Felker St #D http://www.LearnByDestroying.com
> Santa Cruz CA 95060 http://802.11junk.com
> Skype: JeffLiebermann AE6KS 831-336-2558
 
? cell to PC as laptop or handheld is CELLULAR ? not wifi.....the Inspiron here logs cell to PC as wifi...as nomenclature. If the wifi is slid OFF then the PC to tower connection is lost.
 
the S5 line is uh dedicated via liability as a talk op where the PC wifi line isnot that is S5 internet is available where PC wifi doesn't connect.
 
I was abt to look for the Black Rock tower......
 
I'll read later....
Aardvarks <aardvarks@a.b.c.com>: Aug 02 03:04PM

On Mon, 01 Aug 2016 18:47:23 -0400, nospam wrote:
 
>> Like what?
 
> you've been told several times before.
 
Heh heh.
 
Without a google play account, there's nothing for Google to latch on to.
nospam <nospam@nospam.invalid>: Aug 02 11:05AM -0400

In article <nnqcq9$d04$1@news.mixmin.net>, Aardvarks
 
> > you've been told several times before.
 
> Heh heh.
 
> Without a google play account, there's nothing for Google to latch on to.
 
wrong
Jeff Liebermann <jeffl@cruzio.com>: Aug 02 09:40AM -0700


>The primary directions for mobile network antennas and WiFi antennas may
>be different, so one would have to test them independently...
 
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.
 
>Side-by-side (taking this literally) might be yet another influencing
>factor, where one device (might) severely interfere with the other.
 
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.
 
>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, ...
 
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.
 
>I won't do the tests, for several reasons:
 
>- I don't have any Android device available, least several different ones.
 
Borrow one or invite your friends to the test. Or, are all your
friends Apple users? What a horrible thought.
 
>- Where I live I can easily and at any time find several other WiFi
>networks.
 
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.
 
>- 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).
 
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.
 
>Way too bad conditions for performing such a test.
 
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
M Philbrook <jamie_ka1lpa@charter.net>: Aug 01 06:04PM -0400

In article <nnj02g$fv0$1@dont-email.me>, juanjo@benages.eu says...
> measured the voltage, when is over 3.8 volts the machine doesn't work.
 
> I think that i will have to change the complete motherboard, but anyone
> has a better idea?
 
you have a bad voltage regulator that passing through by the sounds of
it.
I bet you have a 3.3V chip set that has a LDO (Low drop out Reg)
running it.
 
If that not being the case, maybe a back flow DIODE is shorted and
allowiing that extra .5 volts or so to pass through. Those are use to
prevent drainage of the battery however, the machine should work with
the charger in it, if not, I'd go back looking for that regulator.
 
 
Jamie
juanjo <juanjo@benages.eu>: Aug 02 12:45AM +0200

El 02/08/16 a las 00:04, M Philbrook escribió:
> it.
> I bet you have a 3.3V chip set that has a LDO (Low drop out Reg)
> running it.
 
Yes, I think thats the problem.
The console also shows that the battery is when in reality is half drained.
But in the end, the fastes and simplest solution is to change the main
board.
 
> allowiing that extra .5 volts or so to pass through. Those are use to
> prevent drainage of the battery however, the machine should work with
> the charger in it, if not, I'd go back looking for that regulator.
 
The console doesn't work with the charger
hellmelt@gmail.com: Aug 01 01:47PM -0700

I found the "secret" menus on the robot, where you can the signal strength and quality.
 
With a small test loop, the values seemed reasonable, and the the quality was 100 (%?). With my large loop (that worked without problem before the thunderstorm) the signal is 0, and the quality is 0. That's weird - what is the problem, the loop itself, or the circuit board in the charging station?
 
You find the menus by pressing 0 for two seconds, and select "Info" and "loop".
 
Anders
"Ian Field" <gangprobing.alien@ntlworld.com>: Aug 01 08:03PM +0100

"asdf" <asdf@nospam.com> wrote in message
news:nnnrv5$ojd$1@gioia.aioe.org...
 
> Capacitor bulging aside, most (all?) PC CD/DVD players have a small hole
> in the front tray cover where a thin wire/hairpin can be pushed to open
> the tray manually. Not sure about stand alone players though.
 
My other DVD player has - but only because I pulled the plastic bit off the
front.
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