QUOTE: " Just out of curiosity, why would you want a 450 ft doublet
resonant at 950 kHz?"
Just to install as much wire in the air as is reasonable. I could string
well over a couple thousand feet, but ....... We live on 40-acres in
Northern Colorado in the foothills of the Rockies. So, why not? It is fed
with parallel conductor XMSN line, a robust (home brew and meticulously
characterized) common mode choke (actually several, depending on frequency)
and an over designed (again, pretty robust) L-Network matching network
(a.k.a., "antenna tuner").
An antenna or set of wires doesn't have to be resonant where one desires to
be a good radiator/receiver of RF energy. I use these wires from
630-Meters (with additional inductance) through 6-Meters. I also have an
NVIS 40-meter dipole and a 6-Meter inverted Vee on the hillside, but seldom
used. Most of the antennas are for radio astronomy and/or ionospheric
profiling (mainly E-Layer).
Dave - W?LEV
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On Tue, Aug 23, 2022 at 6:15 PM Fred Moore <n40cla@...> wrote:
Good afternoon Dave.
Just out of curiosity, why would you want a 450 ft doublet resonant at 950
kHz?
Fred - N4CLA
On Tue, Aug 23, 2022 at 2:01 PM W0LEV <davearea51a@...> wrote:
A dipole, by definition, is resonant: +jX = -jX = 0.
A doublet is a dipole, but not resonant where you require.
My 450-foot doublet exhibits its first 1/2-wavelength resonance at
roughly
950 kHz, but does not show resonance in any of the HF ham bands.
Yes, measurements need to be made to reduce / minimize unwanted
reflections. That's the devil in the details.
Dave - W?LEV
On Tue, Aug 23, 2022 at 5:54 PM Roger Need via groups.io <sailtamarack=
[email protected]> wrote:
On Tue, Aug 23, 2022 at 10:13 AM, W0LEV wrote:
A dipole works fine for the reference antenna. Nominally 2.2_ dB
gain
over
isotropic.
That is the gain of a dipole antenna in free space at resonance. Over
ground the gain is higher. How much higher depends on height and
ground
characteristics.
Roger
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*Dave - W?LEV*
*Just Let Darwin Work*
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Dave - W?LEV
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*Dave - W?LEV*
*Just Let Darwin Work*
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Dave - W?LEV
