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Re: Re: 2.4GHz QRM, hop



WIFI, Bluetooth and Cordless phones work much
differently.

WIFI, will sit on 1 channel until you manually change
channels.  WIFI does not Channel hop the way a
cordless phone or Blue tooth hop

The old channel numbers on 2.4 Assumed each channel
was 5 meg apart.  However current wifi needs 22 meg.

Wifi Sits on a channel and sucks up ~22 MHz.
It will hop inside its 22 meg channel.  
All of the wifi hopping stays within its 22 meg
channel.

Blue tooth is different.
It divides up the band 2401 - 2478 into 78,  1 meg
channels.  When Bluetooth hops, it will use all
78 channels at all times.
Bluetooth 2.x Should listen for busy channels and
avoid them.  At least in theory.

Cordless phones,  Every manufacture can choose their
own format.  most use a hopping plan similar to
Bluetooth, in which they hop the whole band 2401 
2478.
On older 2.4 phones you could set a specific channel. 
Most new phones use a Bluetooth style hopping.  What
we need is for the 2.4 phones to adopt the Bluetooth
busy channel mode.

Ham power.
I think the power limit for WIFI for Hams on Channel
#1 is aprox 290 watts ERP.
I seem to recall seeing a special rule for hams and
Spread-Sprectrum.
If you Run normal voice or CW on 2401 area, is aprox
1500 raw power.
WIFI for public in the USA is aprox 4 watts ERP.




--- John Mock <kd6pag@qsl.net> wrote:

> One thing that might help, at least in some case,
> would be if someone
> (AMSAT and/or ARRL) would come up with a very
> professional looking
> handout explaining Part 15 (perhaps includes a
> picture of a Part 15
> sticker which clearly states that the user must
> discontinue use until
> the interference problems are resolved), and how to
> avoid interference
> with other services.  If there were a references and
> a webpage to go
> to, that might help as well.  Most of us don't
> specialize in diplomacy,
> so having something printed might help.
> 
> Another thing we might do is to add information to
> the Wikipedia articles 
> on WIFI and other 2.4 GHz devices which mentions the
> conflict and suggest 
> that manufacturers and user select Channel 1 only if
> all other channels 
> fail.
> 		       -- KD6PAG  (Networking Old-Timer, Satellite
> QRPer)
> ----
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> those of the author.
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