RadioBanter - View Single Post - 50 Ohms "Real Resistive" impedance a Misnomer?

July 23rd 03, 09:14 AM

(Art Unwin KB9MZ) wrote in message m...

1. Two antennas (also called transducers) placed close together
actually can be considered a transformer, albeit a very inefficient
one.

Humm...By antenna I assume it also means a radiator. This would
suggest
that a stagger tuned radiators would fall into the catagory discussed
above.
Now I have a problem with that statement, because I very much see it
as a transformer which is VERY efficient and not as you stated "albiet
a very inefficient one".
Can you explain to me how a stagger tuned antenna migrate into
inefficient radiators?
Seems to me that Thevenin's theorem would show this as being
incorrect !

Well, two identical antennas spaced a few wavelengths apart can
be considered a transformer, but very inefficient compared to a "real"
transformer with identical primary and secondary turns, with an
appropriate toroid core. This would be because the core material will
increase the magnetic flux density, and will increase the coupling
between the two windings/transducers.

Point is, the farther apart the antennas are, the less efficient
of a "transformer" they will be.

I'm not familiar with stagger tuned antennas, although the name
would suggest that it is tuned for multiple resonances, so that the
antenna will be broadband.

Slick