Roy Lewallen wrote:
So what I'm asking for is an inductor value
which would exhibit a large enough phase and/or magnitude shift that
would be easily seen in a measurement.

How about a coil with 180 degree phase shift as described by Kraus?

"A coil can also act as a 180 degree phase shifter as in the collinear
array of 4 in-phase 1/2WL elements in Fig. 23-21b. Here the elements
present a high impedance to the coil which may be resonated without
an external capacitance due to its distributed capacitance. The coil
may also be thought of as a coiled-up 1/2WL element."

Here's the diagram in 23-21b

--------------coil-------------FP---------------coil----------------
1/2WL 1/2WL 1/2WL 1/2WL

The coils are designated as "Phase-reversing". Each coil occupies 1/2WL
electrically.

Have you never encountered phased arrays like the above or understood
that the coils are causing a 180 degree phase shift? That's the way
my Diamond 440 MHz mobile antenna works.
--
73, Cecil http://www.qsl.net/w5dxp



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Cecil, W5DXP wrote:
"Here is the diagram in 23-21b."

Thanks, Cecil. My copy of Kraus is new and I`d not yet read page 824.
Kraus says:

"The coil may also be thought of as a coiled-up halfwave element."

I like his preceding sentence:

"Here the elements present a high impedance to the coil which may be
resonated without external capacitance due to its distributed
capacitance."

A "phase reversing coil" does present a 180-degree phase shift between
its ends.

Best regards, Richard Harrison, KB5WZI

Can we make a physically small "phase reversing coil" that has 180
degree phase shift between its ends? If so, how?

Roy Lewallen, W7EL

Richard Harrison wrote:
Cecil, W5DXP wrote:
"Here is the diagram in 23-21b."

Thanks, Cecil. My copy of Kraus is new and I`d not yet read page 824.
Kraus says:

"The coil may also be thought of as a coiled-up halfwave element."

I like his preceding sentence:

"Here the elements present a high impedance to the coil which may be
resonated without external capacitance due to its distributed
capacitance."

A "phase reversing coil" does present a 180-degree phase shift between
its ends.

Best regards, Richard Harrison, KB5WZI

Roy, W7EL wrote:
"Can we make a physically small "phase reversing coil" that has 180
degree phase shift between its ends? If so, how?"

Yes. Kraus was discussing collinear arrays composed of 1/2-wave elements
interconnected by phase inverters to keep the currents in all elements
in-phase, that is, flowing in the same direction.

More than the phase delay of the coil is involved. Its self-capacitance
is involved in making a parallel resonant circuit at the operating
frequency.

The phase relations would be the same for a smaller inductance shunted
with a larger capacitance.

Two reasons for using self resonance; simplicity and wider bandwidth
with the low-C circuit.

These parallel resonant circuits replace short-circuit 1/4-wave stubs in
some collinears.

Best regards, Richard Harrison, KB5WZI

Roy Lewallen wrote:
Can we make a physically small "phase reversing coil" that has 180
degree phase shift between its ends? If so, how?

Why are you so hung up on physically small coils? The subject is
center-loading coils on mobile antennas, like bugcatchers.
--
73, Cecil http://www.qsl.net/w5dxp



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