At last found where the two beasts are.
one is little one and  other is a big one :D 

The little beast - device was to hot.

I have disassemble plastic cover, and was using usb adapter 
without plastic cover. When i decided to change usb port and to use usb cable 
(1,5 m in length ), 
i find out that chip   (rtl8187b; 74307S1; G716D TAIWAN)
is quite hot (betwen53C and 60C).

The big beast - device was directly connected to laptop usb port
(and maybe pick up some nice interference from build in intel wireless card or 
from another electric circuit ).

I tested few positions with usb cable and find out that it really matter 
adapter orientation,
and  how far away  adapter is from laptop (in my situation about 70cm was 
enough to get good results ).
 
Test results:

without cooling (chip rtl8187b up to ~59C) 
and with usb cable about 70cm from laptop, adapter is hanging down with led 
pointing to router.

--- 10.0.0.138 ping statistics ---
208 packets transmitted, 127 received, 38% packet loss, time 207181ms
rtt min/avg/max/mdev = 0.806/3.346/148.845/13.007 ms

with cooling (chip temperature up to 34C) 
and other things are all the same

starting cooling:
--- 10.0.0.138 ping statistics ---
204 packets transmitted, 181 received, 11% packet loss, time 203239ms
rtt min/avg/max/mdev = 0.752/3.685/174.709/17.437 ms

hand get tired and i put ventilator on the table

--- 10.0.0.138 ping statistics ---
111 packets transmitted, 110 received, 0% packet loss, time 110108ms
rtt min/avg/max/mdev = 0.695/5.633/228.638/26.297 ms

while downloading gimp windows install (86,0 MB) and still cooling

--- 10.0.0.138 ping statistics ---
194 packets transmitted, 193 received, 0% packet loss, time 193214ms
rtt min/avg/max/mdev = 0.727/14.372/749.374/72.800 ms


still cooling :D
--- 10.0.0.138 ping statistics ---
225 packets transmitted, 225 received, 0% packet loss, time 224268ms
rtt min/avg/max/mdev = 0.721/3.329/193.260/17.353 ms



So i am not an expert on electric circuit, neither on usb wireless adapters 
electronics,
but it is really something to do with drivers and maybe power management or 
power consumption for some routines.
Maybe windows drivers use smarter algorithms to do the same job than linux 
drivers,
and that's why chip in linux has more job, use more power and gets over hot and 
starts malfunction?
Or maybe it is usb power management? 
But to answer exactly man need to have knowledge and understanding about this 
device (chipset), or 
in another words need team assistance which crated this device (chipset).


So problem solution is to put cooler and use usb cable :D

But still annoying why in windows it works ok even when adapter is hot
and on linux need to be cooled down to 30C ?

-- 
You received this bug notification because you are a member of Ubuntu
Bugs, which is subscribed to Ubuntu.
https://bugs.launchpad.net/bugs/802902

Title:
  Realtek rtl8187b wireless chipset slow speed

To manage notifications about this bug go to:
https://bugs.launchpad.net/linux/+bug/802902/+subscriptions

-- 
ubuntu-bugs mailing list
ubuntu-bugs@lists.ubuntu.com
https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs

Reply via email to