In article
,
"Frank Dresser" wrote:

dxAce wrote:


Yes, why try to belabour the point?

I recognized Telemon's antenna formula as something very much like
the transmission line formula. I'm not sure how it applies to
resonant receiving/transmitting end fed wires. If it does, I'd like
to learn something.

Yes. Because it is a single wire (Marconi type) antenna the RF
reference is the ground so that is where the simplified equation comes
from. Air is the dielectric (1) where the two conductors are the wire
and ground under the wire. The distance between the two conductors and
the size (diameter) of the conductors determine the characteristic
impedance of the path.

But, generally, I don't see much point in trying to caluclate a
receiving antenna's impedance.

The original poster specifically asked the question.

He'll do just fine to plug the dang wire into the 500 ohm input. If
he wants or needs to do better he can improvise a matching
transformer, keep his antenna away from the house or whatever and
then feed the 50 ohm port.

You bet.

That's right.


This ain't rocket science, though a few minor details can enhance
performance.

I just wanted to make the point that if people want to use the Marconi
type antenna that the return is ground. Ground is the other half of the
antenna. There are always two elements to an antenna because the RF
needs to complete a loop just like a battery in a DC circuit. You have
to connect both sides of a battery to a circuit for it to work,
everybody understands that but people forget that an RF circuit needs
to complete a circuit loop in a similar way.

Not only that, but the rocket scientists stay stuck on the ground!

Other than time spent in a few plane trips I'm earth bound.

--
Telamon
Ventura, California