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Re: An experiment 2.4 GHz SS Cordless vs Weak Signal



>
> > think we need to design a 2.4g beacon that we can put in our yard to
help
> > keep 2.4g phones away.
> > W4SCO
>
> Easy, a Microwave oven on the roof with the door open...
>

I'll ignore the obvious comments, but make this one instead  - a 'source' at
2450MHz (magnetron frequency used by microwave ovens to resonate water
molecules) is too far away (in frequency).  A frequency agile SS phone would
see that 2450 is blocked and go somewhere else - like 2401 - not good.  What
would be needed is a source much closer to 2401, such as a 'personal
attended beacon' on 2402 MHz - far enough away from the downlink such that
the 144MHz IF radio would filter it at the IF frequency, but close enough so
that the phone would think that it is a blocked channel, and go somewhere
less intrusive such as 2410, 2420 or whatever.  It would help to keep WLANs
away as well.

In the UK, a personal attended beacon is quite legal for hams. And, if the
power is less than 100mW, you don't even need an amateur radio licence -
anybody can do just about anything with this part of the spectrum; no type
approval is required as long as the power is below the 100mW threshold (and
there may also be limitations on high gain aerials).  But if you have an
amateur radio licence, you can run the legal limit.....

Maybe we are lucky (so far), but I don't think that there are many 2.4GHz
cordless phones here in the UK, although there are now quite a few wireless
video links at this band, and they are not ussually frequency agile.

Grant G8UBN

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