On Sat, 15 Oct 2005 18:26:30 +1000, Alan Peake
wrote:


Sorry, that should be:

"that when algebraicly
Actually, that should be "algebraically"

Thanks. There were some other typos along the way, but that was
clearly a spelling mistake and the spell checker didn't find it.

Interesting thread though. BYW, is the Bird using the Bruene type bridge

Is that BTW?

I understand that the Breune type bridge is one of the bothways
detector designs with a untapped toroidal current transformer. I doubt
the Bird sampler element is of that type.

It appears to have a flat section of line that is parallel to the coax
centre conductor and is presumably capacitively and inductively
coupled, and it uses some form of frequency compensation to give it
broadband response. You rotate the sampler element for measurement of
the opposite direction.

Someone here may have dismantled one to see how it works.

I suspect that all of these probe designs try to sample net V and I at
a point, and the extent by which they depart from a point sample
limits their upper frequency of usefulness.

Though there are several designs, they seem to broadly fall into two
main types, those where the sampler response is inherently
proportional to frequency (though they may be compensated as in the
Bird elements) or those where they are inherently broadband (as the
Bruene circuit).

Trust you are well. I heard you on 40m the other day, but only just!
Propagation has been pretty shabby.

Owen
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