JT> Is RF a suitable alternative? Some UHF car alarm keys go for
JT> that sort of distance easily. Not directional and quite low
JT> power consumption. 

> UHF is the obvious answer. But then it wouln't be infrared. 

JT> Why is infrared _required_? I've never seen any infrared
JT> outdoor remotes, simply because of the SNR problems.

   I'm an engineer. If someone asks me how to move 1,000 litres of
blood a minute to Melbourne, I just work out the size of the pipe. I
never ask where all the blood is coming from.

Regards,
Bob


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