In article ,
T i m wrote:
On Sun, 13 Feb 2005 11:18:01 +0000, Dave Stanton
wrote:


Indeed, but I was just questioning if the 'rules' covered power to the
antenna or radiated from it?

All the best ..

T i m

With most things RF and goverment rules its radiated power that counts,
that way it covers antennas with gain.... crafty blighters !!

I suppose a problem with that could be 'how' that signal is radiated
and how 'close' to the upper tested limits the manufacturers sail?

ie, One make / model of WiFi kit is 'known' to work better (afa range
lets say) than may others? Or have more options that may help
propagation.

It's not just power - it's got a lot to do with the hardware/software that
decodes the radio signals on the reciever... When I was experimenting
with kit some years back, I found that DLink were utterly rubbish in
that recpet and were very poor at suppressing reflected signals. So
when they were in a good line of sight situation, all was well, but
make it non-line of sight, or in a otherwise poor reception area, and
the reciever would have real problems sorting out duplicate packets -
as a result throughput was dramatically reduced...

They may have fixed this by now, but I did speak to their technical
people, but they didn't seem too interested... As as result when the
time came to deploy several 100 recievers, they didn't get a look-in.

Ignoring the risk to humans from microwaves, I think what should be
important to those who set the rules is what proportion of signal
get's out past my boundries. Ie, if I lived in a Faraday cage I could
(should be able to) use whatever power I like ;-)

I've heard (and no-ones ever refuted this, it *may* be UL!!!) that the
radiated power avalable in the 2.4GHz range is all down to the amount
of radiation a domestic microwave oven is allowed to leak... People make
such song and dance about whinging about the power levels of WiFi when
a mobile phone is allowed to chuck out some 40 times more power...

So, if I want to get a signal down to my workshop I should be allowed
to do whatever re the (max) power available (I'm talking antenna here)
as long as the rf that actually makes it out of my house is below the
permitted maximum?

I know the above is pretty unworkable in the real world but you get
the idea ...

The reality is that no-ones going to come after you ... unless you start
to cause interference... One town we installed in complained that we were
interfering with the town CCTV system - which also used the 2.4GHz band
(it's also knows as the ISM band - Industrial, Scientific and Medical,
used for instrumentation of various sorts, and low power analogue CCTV,
etc.) As our kit was off the shelf stuff, we were inside the limits,
and once we knew that their kit was on the 2,4GHz band, we really
really wondered how they were getting the signal from the cameras back
to the base, as we really couldn't get signals into the areas they were
getting signals...

There are 2.4GHz amiplifiers avalable... However if you are not careful,
you'll end up amplifying noise too. (Signal to noise ratio being important
here) I always try to get the output power set as low as possible which
will maintain a good signal rather than just set it to max. (On units
which allow you to vary the power)

If WiFi is out of the question, I assume you have power down to the
workshop, so looking into Ethernet over mains might be an answer...

Gordon