2.8
- Working at disallowed channels and exceeding power output limits
- Because
every country in the world has got its own legislation regarding to
the radio spectrum, it is important to know which are the channels
and output power allowed in every place. Moreover, each wireless
network interface has got its own default regulatory settings.
- First
of all, assuming we are in the United States (US), let's take for
instance the US regulatory domain:
- This
new setting is immediately detected by the log file of the system:
- In
the US regulatory domain is perfectly possible to use channel 11:
- But
it is not allowed channel 12:
- About
the power output, maximum allowed is 27 dBm (500 mW):
- For
that reason, 30 dBm ( 1 Watt) is rejected:
- Now,
although being physically in the US, the regulatory domain can be
changed, for instance to Bolivia (BO):
- Again,
the log file records the news:
- Now,
the system allows to use both channel 12 (2.467 GHz) and power 30 dBm
(1 Watt), because Bolivian regulatory domains are different from the
US:
- What
to do for using the all over the world forbidden channel 14? the
answer is to change to Japanese regulatory domain, because Japan is
the only country in the world allowing channel 14:
- The
log informs about the changes:
- Verifying
that the wireless interface card is now working at the forbidden
channel 14 (2.484 GHz):
- From
this practice, we conclude that although in each country there are
unlicensed wireless bands and strict power limits specified, all
those regulations can be overwritten changing the regulatory domain
to other country. In this way, the wireless interface card is forced
to work at:
- disallowed channels
- more than allowed power transmission
