Richard Clark wrote:

wrote:
If the coil was resonant, you wouldn't need the rest of the antenna.

Uh-huh, makes a trap an antenna?

A helical trap could be a 1/2WL antenna. But we are better off
with a good ground plane and a 1/4WL helical antenna since it
matches our 50 ohm transmitter better and has less loss. The
ground plane furnishes half of the antenna.
--
73, Cecil http://www.qsl.net/w5dxp



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Richard Clark wrote:

wrote:
BS, Richard. If they were series resonant how could they possibly
supply any inductive reactance which is what is needed to neutralize
the capacitive reactance of the short antenna? A "SERIES RESONANT
loading coil" is purely resistive, by definition.

and the cow jumped over the moon

And Little Richard laughed to see such a sight, or maybe cried.
--
73, Cecil http://www.qsl.net/w5dxp



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C'mon Richard. Everybody who works in electronics knows that capacitors
are RESONANT, self resonant.

Everybody who works in electronics knows that inductors are RESONANT,
self resonant.

At general RF frequencies the self resonances are significantly higher
frequencies than the design frequency resonance.

Get a Boonton 'Q' meter and go measure some. Then we can celebrate the
funeral of this thread and really get into something interesting like
'Does the charge to mass ratio of an electron remain constant as it
approaches relativistic speed?' Pops! Wrong group.

DD

Not only that, Yuri, but he is desperately trying to change the subject away
from the original. Have you noticed? That logical diversion, diverting the
issue,
is much older than Richard and won't work against people who recognize it.
--
73, Cecil http://www.qsl.net/w5dxp


Yep, it's getting pathetic, looks like graduates from W8JI "university". Time
to move on to some serious work with those who see the light. I want to explore
inductopacitive loads. WX is warming up, the white sh1t is melting, I will get
out soon, and do some more 'sperimenting.
We are trying to have mobile ant shootout here in the spring.

Yuri, K3BU.us

Richard Clark wrote:
"Uh-huh, makes a trap an antenna?"

A trap usually isn`t the best radiator.

A 1/4-wave shorted stub is electrically equivalent to a parallel
resonant circuit, so they are interchangeable. You can use a parallel
resonant circuit to replace a 1/4-wave shorted stub or vice versa.

VHF collinear antenna arrays often use 1/4-wave shorted stubs to invert
the phase at 1/2-wave intervals to keep the current going in the same
direction in all elements.

The Franklin antenna is a vertical collinear array used by some medium
wave broadcasters. A 1/4-wave stub would be inconvenient for the medium
wave broadcaster, so he sometimes uses a parallel resonant circuit for
his phase inverter between 1/2-wave collinear elements.

You might think the parallel resonant circuit or 1/4-wave shorted stub
would function as a trap. Traps are used in multiband antennas. But the
parallel resonant circuit does not function as a trap in collinear
arrays. The length of the element beyond the tuned circuit is 1/2-wave
resonant and readily accepts power through and around the tuned circuit.
Not so with a trap. The length of the element beyond the trap is not
resonant and accepts very little power. The trap is an isolator which
keeps power out of the extension beyond the trap. The phase inverter is
a coupler which conveys energy with a phase reversal produced by the
inverter.

Best regards, Richard Harrison, KB5WZI