#4068 NORM Never A: Range of communication between 2 XOs is limited only to 20 meters

[Zarro Boogs per Child]

#4068: Range of communication between 2 XOs is limited only to 20 meters
-----------------------+----------------------------------------------------
  Reporter:  arjs      |       Owner:  jcardona        
      Type:  defect    |      Status:  new             
  Priority:  normal    |   Milestone:  Never Assigned  
 Component:  wireless  |     Version:                  
Resolution:            |    Keywords:  wireless , range
  Verified:  0         |  
-----------------------+----------------------------------------------------
Changes (by arjs):

 * cc: mbletsas at laptop.org, walter (added)


Comment:

 ===Posting communication with Michail here so that all discussion is in
 one place===

 Michail

 These are the serial numbers that I have at hand...
 SHF72500350
 SHF72500356
 SHF72500354
 SHF7250033C
 SHF72500341
 SHF72500316
 SHF7240000E
 SHF7250034E
 SHF72500328
 SHF72500327
 SHF7250034D
 SHF72500347
 SHF72500338
 SHF7250032E
 SHF7250034F
 SHF72500306
 SHF7250034A
 SHF72500352
 SHF72500359

 Carla
 - Hide quoted text -

 On 10/8/07, Michail Bletsas <mbletsas at laptop.org> wrote:


     Arjun,

     From your description, it doesn't seem that electromagnetic noise
 could be an issue and you probably ended up with a batch of XOs with very
 bad antennas.
     I would appreciate if you could send me the serial numbers  from the
 sticker in the battery slot.

     20 meters is just too short.

     M.



     "Arjun Sarwal" <arjun at laptop.org>
     Sent by: arjunsarwal at gmail.com

     10/07/2007 02:01 PM

     To
         "Michail Bletsas" <mbletsas at laptop.org>
     cc
         amit.gognaa at gmail.com, carla at laptop.org, "Manusheel Gupta"
 <manu at laptop.org>, "John Watlington" <wad at laptop.org>, "Walter Bender" <
 walter at laptop.org>
     Subject
         Re: Wireless test results - pilot project at Mumbai







     Michail,

     We did repeat the experiment many times and on different days. We were
 holding the XOs in our hands and were keeping them above our waist level
 and slightly near our faces.

     We were in an open field. There are a medium amount of trees around
 but none that were even close to obstruct line of sight between two XOs.

     School server was switched off.  We just did a simple ping from one XO
 to other. When the ping stopped coming we did ctrl-c and started ping
 again just to make sure.


     Any way to measure the noise level (associating with an Access Point
 will yield approximate measurements - mesh mode measurements don't produce
 very useful information)? Sounds like you operate in a very noisy
 environment.

     Could you please let me know what kinds of noise affect such a range ?
 (EMI, presence other wireless networks ?)

     The place where we carried out testing was at Pilot site. It is a
 village in the middle of nowhere where even the mobile network signal
 strength is low. The mobile band in India is 900Mhz. There are no wireless
 networks/access points till tens of kilometers away (Id say atleast ~20
 kms)

     Anyway we have brought few XOs back with us and would repeat tests
 near the hotel tomorrow.


     The hardware version is B4 6 and the build is 601. What tests can we
 do to help zero down whether it is a hardware or a software problem ? We
 could install an earlier OS image and repeat tests, which one would you
 recommend ?


     Thank you,
     Arjun

-- 
Ticket URL: <https://dev.laptop.org/ticket/4068#comment:3>
One Laptop Per Child <https://dev.laptop.org>
OLPC bug tracking system