RadioBanter - View Single Post - What's a better HF receive-only antenna: MFJ-1024 or a loop?

May 22nd 05, 07:07 AM

In article ,
(Mark Zenier) wrote:

In article , dxAce
wrote:

wrote:

I suppose you could use the term untuned dipole, but I think most
people would interpret the term incorrectly. Functionally, both
are random lengths of wire.

If one has a dipole would it not be 'tuned' or 'resonant' on some
frequency?

Resonance just means that it's operating at a point where the
inductive and capacitive reactances are equal. A non-resonant dipole
is still picking up the signal, it just presents it as an impedance
that is mismatched to the transmission line (or receiver).

In general for RF circuits resonance means reactance is zero like you
said but antennas have a different spin on things.

The when the electrical "size" of the antenna is the same as a passing
EM wave the ability of the antenna as a "transducer" between a far field
and a local circuit is enhanced. Anyone that has used an antenna cut for
a band has experienced the best gain the antenna has to offer on that
band.

The best analogy I can think of is a tuning fork that will ring when
another of the same size is generating its resonant tone nearby.

--
Telamon
Ventura, California