On Mon, 1 Aug 2016 13:03:59 +0200, Michael Eyd wrote:
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).
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.
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.
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
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060
http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558