Extract from program notes.

Program Name: NOTATRAP.exe Author: R.J.Edwards G4FGQ

A TWO-BAND ANTENNA WIRE LOADED WITH AN L & C PARALLEL-TUNED CIRCUIT

The LC parallel-tuned circuit is constructed exactly like an antenna trap.
It
is located in the antenna wire and used as L or C loading at 2 other
resonant
frequencies. Parallel-tuned circuits have a reactive impedance on either
side
of resonance. On the low frequency side there is a +ve inductive reactance.
On
the high frequency side there is a -ve capacitative reactance.

The purpose of the LC loading components is to detune the antenna wire from
its natural 1/4-wave resonant frequency. When the loading circuit is
behaving
as an inductance the antenna resonant frequency is reduced. When the loading
circuit is behaving as a capacitor the antenna resonant frequency is
increased.
The pair of resonant frequencies depend on the LC ratio, on wire length, and
on the location of the LC loading circuit along the wire.

For a given loading location along the wire and a given pair of resonant
freq-
encies this program calculates the L and C loading-component values. The
pair
of frequencies lie above and below the unloaded resonant frequency of the
wire.
The LC circuit behaves as an ordinary trap at its own resonant frequency
which,
by experiment, can sometimes be arranged to fall into a third amateur band.
But
to calculate such a fortunate coincidence is beyond my elderly patience.

The program has a built in signal source which generates a wide-ranging
testing frequency which can be used to 'measure' the input impedance of the
antenna versus frequency, checking resonant frequencies and other antenna
characteristics.

Download program NOTATRAP from website below and run immediately.
----
.................................................. ..........
Regards from Reg, G4FGQ
For Free Radio Design Software go to
http://www.btinternet.com/~g4fgq.regp
.................................................. ..........

Reg,
Can this be conscrewed as a combination loop/.dipole?
It would appear that you can place the L/C circuit at the center of the
dipole and fed either with a delta match or a capacitive /inductive coupled
dipole for impedance purposes. Could not quite fathom from your notes what
it was exactly. I made a 160M rotatable dipole last winter based on the
above and used the radio auto tuner control to change the values on the L/C
circuit to move up and down the band because of the resulting narrow
bandwidth at any set frequency or band.
Art

"Reg Edwards" wrote in message
...
Extract from program notes.

Program Name: NOTATRAP.exe Author: R.J.Edwards G4FGQ

A TWO-BAND ANTENNA WIRE LOADED WITH AN L & C PARALLEL-TUNED CIRCUIT

The LC parallel-tuned circuit is constructed exactly like an antenna trap.
It
is located in the antenna wire and used as L or C loading at 2 other
resonant
frequencies. Parallel-tuned circuits have a reactive impedance on either
side
of resonance. On the low frequency side there is a +ve inductive
reactance.
On
the high frequency side there is a -ve capacitative reactance.

The purpose of the LC loading components is to detune the antenna wire
from
its natural 1/4-wave resonant frequency. When the loading circuit is
behaving
as an inductance the antenna resonant frequency is reduced. When the
loading
circuit is behaving as a capacitor the antenna resonant frequency is
increased.
The pair of resonant frequencies depend on the LC ratio, on wire length,
and
on the location of the LC loading circuit along the wire.

For a given loading location along the wire and a given pair of resonant
freq-
encies this program calculates the L and C loading-component values. The
pair
of frequencies lie above and below the unloaded resonant frequency of the
wire.
The LC circuit behaves as an ordinary trap at its own resonant frequency
which,
by experiment, can sometimes be arranged to fall into a third amateur
band.
But
to calculate such a fortunate coincidence is beyond my elderly patience.

The program has a built in signal source which generates a wide-ranging
testing frequency which can be used to 'measure' the input impedance of
the
antenna versus frequency, checking resonant frequencies and other antenna
characteristics.

Download program NOTATRAP from website below and run immediately.
----
.................................................. .........
Regards from Reg, G4FGQ
For Free Radio Design Software go to
http://www.btinternet.com/~g4fgq.regp
.................................................. .........

On Thu, 23 Sep 2004 00:46:51 GMT, "
wrote:
Reg,
Can this be conscrewed
---- must :-) ------ not :-) :-) ------ laugh :-) :-) :-)

"aunwin" wrote -
Reg,
Can this be conscrewed as a combination loop/.dipole?

======================================

Aunwin, it would be impolite of me not to reply to your direct question. But
for ages, on and off, I have tried at regretably increasing intervals,
entirely unsuccessfully, to understand what your combination loop/dipole is
all about.

So although YOU may somehow manage to construe some sort of relationship
between a loop/dipole, whatever it is, and a lumped LC circuit inserted in a
random length antenna wire, I'm afraid I'm in great difficulty.

In view of the amount of work involved, and the likelihood of it being
fruitless, I propose for the time being to leave the matter in my pending
tray and pour myself a glass of Bordeaux Claret. If unfamiliar with the
beautiful deep red liquid you may like to try a glass yourself. It does
help.

I'm very sorry that at present I'm unable to be of more assistance in your
quest for recognition.
----
Yours, Reg, G4FGQ.

Reg,
You emphasise that "it is not a trap", a trap being a loop circuit that
provides a desired low impedance path and a blocking high impedance for
another band. You go on to say that the circuit you refer to allows all of
the antenna to be used for both bands! Thus the L/C loop
must provide a low impedance path on BOTH bands according to your statement
which is certainly different to a "trap".
From your statements I thus see your
L/C cuircuit as a "loop" which can be
placed at an apropriate point in a radiating element.
Les Moxon refers to a similar antenna in his book where the loop is placed
in the center of a dipole and which he calls a resonator having a capacitor
and inherrent inductance.
It was Moxons antenna ,which is what I refer to as a combination loop
/dipole antenna, that illustrates the use of an L/C circuit in antennas and
what I used as a basis for my 160M antenna which worked quite well. Thus it
was your own comments that instigated the original question.
Hopefully when you read this your mind will not be in a befuddled state
created by claret and before you waddle of to the local pub so that you can
respond without sarcasm
Best Regards
Art

"aunwin" wrote -
Reg,
Can this be conscrewed as a combination loop/.dipole?

======================================

Aunwin, it would be impolite of me not to reply to your direct question.
But
for ages, on and off, I have tried at regretably increasing intervals,
entirely unsuccessfully, to understand what your combination loop/dipole
is
all about.

So although YOU may somehow manage to construe some sort of relationship
between a loop/dipole, whatever it is, and a lumped LC circuit inserted in
a
random length antenna wire, I'm afraid I'm in great difficulty.

In view of the amount of work involved, and the likelihood of it being
fruitless, I propose for the time being to leave the matter in my pending
tray and pour myself a glass of Bordeaux Claret. If unfamiliar with the
beautiful deep red liquid you may like to try a glass yourself. It does
help.

I'm very sorry that at present I'm unable to be of more assistance in your
quest for recognition.
----
Yours, Reg, G4FGQ.

Art,
'How' you think of, or envision a particular antenna is entirely
up to you. But, when you want to communicate your thoughts about that
antenna to people who do not 'envision' antennas in the same way that
you do, you have to use commonly acceted means/terms. If you don't,
there will always be misconceptions/errors in understanding what you
are trying to say (doesn't matter if the 'what' is correct or not).
I think the problem is in the 'translation'.
'Doc


It's still a nickname. I didn't 'pick' it, it was given to me.
It doesn't mean I'm a 'doctor' of anything (I'm not!). Sorry if
it still bothers you, get over it.

On Fri, 24 Sep 2004 15:02:58 GMT, "
wrote:
Present focus is on following the thread where Richard
More trolling

Go get them Richard, you do an excellent job of culling the ranks of radio
amateurs
None, as yet, have stood up to your perpetuation of stone throwing or
spitting because of your high acid content.
Nuff said, I have things to do
outside this newsgroup.
Art
"Richard Clark" wrote in message
news
On Fri, 24 Sep 2004 15:02:58 GMT, "
wrote:
Present focus is on following the thread where Richard
More trolling

On Fri, 24 Sep 2004 17:27:18 GMT, "
wrote:
I have things to do
outside this newsgroup.
write when you find work.