weird WIFI route

[geoffrey mendelson]

On Dec 27, 2009, at 12:40 PM, Hetz Ben Hamo wrote:

> Hi,
>
> I'm using this machine with wifi connection and I noticed something  
> really weird..
>
> When browsing the net I saw that sometimes I didn't get the DNS  
> resolving. I added DNS servers to resolv.conf, even setup my own DNS  
> server. That didn't help.
>
> So I tried to ping some sites and then I saw it took quite a long  
> time until it started ping even specific IP numbers. I checked  
> "route" and then I saw the problem.. it shows the routes, pauses for  
> few seconds and then shows the default gateway (which is an internal  
> IP).
>
> I replaced the router to Linksys which works OK, but I still get  
> those problems. It's not an issue of signal strength (it's around  
> 70-80% here).

Israel is probably the worst place in the world for Wifi. The IDF uses  
2.4gHz for all sorts of things, the most problematic for Wifi is  
ground to air radar.
In 2003, $800m was allocated to move the IDF off of WiFi channels 4-8,  
which was supposed to have been done by November of 2003.

The other channels are still used by the IDF, they were not supposed  
to be released for civilian usage. Bluetooth, except for very short  
range communications also uses those frequencies. In 2005 Omri Sharon  
went overseas and came back with a really interesting Bluetooth  
device, and showed it to his father. He liked it so much he declared  
that all Buletooth frequencies and all WiFi frequencies are legal for  
civilian use in Israel.

This did not affect the IDF, they still continue to use whatever they  
have, except on WiFi channels 4-8.  5.8gHz (802.11n) is illegal in  
Isreal. luckily, 802.11n can use either 2.4gHz or 5.8gHz.

All sorts of other things affect Wifi signals, reflections can null  
them out, interference from 2.4gHz cordless phones, microwave ovens,  
other wifi networks, etc can interfere.  Strong signals can overload  
the receiver and cause your signal to be lost, even if they are not on  
the same frequencies.

BTW, 70-80% is awfully low. It's fine for communications to the  
Internet hot spot down the street, but I find that anything less than  
90% is problematic.
I have also found that using both a CARDBUS 802.11g wifi card and a  
buletooth dongle on the same computer cause problems. It shows up as  
WiFi signals going from around 70% (which is already low) to 55%  
(which is just about unuseable). Removing the dongle, or connecting it  
via a 1 meter extension cable cleared that up.

Since the numbers are relative anyway, what do they actually mean?

Note that the limit on radiated power in Israel (EIRP) is 100mw, which  
is what a router already puts out. Gain antennas when used for  
transmitting or high power Wifi cards bring you over the legal limit.  
I have been looking for a router (or access point) that has a separate  
receive antenna, but can not find one.


Geoff.
-- 
geoffrey mendelson N3OWJ/4X1GM
Jerusalem Israel geoffreymendelson at gmail.com
New word I coined 12/13/09, "Sub-Wikipedia" adj, describing knowledge  
or understanding, as in he has a sub-wikipedia understanding of the  
situation. i.e possessing less facts or information than can be found  
in the Wikipedia.