Discussion:
Efficiency of HF mobile antennae?
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Gareth's Downstairs Computer
2018-02-07 09:49:18 UTC
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A question for those who work HF mobile; do you feel that
having a loading coil and a short whip materially affects
your QSO capability, as the text books suggest, for if
not it would seem to suggest that we could all manage
with such antennae as our main base air transducers?
Jim.GM4DHJ ...
2018-02-07 09:54:48 UTC
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"Gareth's Downstairs Computer"
Post by Gareth's Downstairs Computer
A question for those who work HF mobile; do you feel that
having a loading coil and a short whip materially affects
your QSO capability, as the text books suggest, for if
not it would seem to suggest that we could all manage
with such antennae as our main base air transducers?
you have to make a compromise between /m usability and pure performance of
the antenna I have found the short jap base loaded jobs work just as well as
a centre loaded ungainly hustler when moving .......and you worry less
Gareth's Downstairs Computer
2018-02-07 09:59:14 UTC
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Post by Jim.GM4DHJ ...
"Gareth's Downstairs Computer"
Post by Gareth's Downstairs Computer
A question for those who work HF mobile; do you feel that
having a loading coil and a short whip materially affects
your QSO capability, as the text books suggest, for if
not it would seem to suggest that we could all manage
with such antennae as our main base air transducers?
you have to make a compromise between /m usability and pure performance of
the antenna I have found the short jap base loaded jobs work just as well as
a centre loaded ungainly hustler when moving .......and you worry less
OK, but how do you find the QSOability in comparison to your
home antenna?

(Cue: 1/4 mile nonsense from the Mongolian Hordes of nonces)
Jim.GM4DHJ ...
2018-02-07 10:50:52 UTC
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"Gareth's Downstairs Computer"
Post by Gareth's Downstairs Computer
Post by Jim.GM4DHJ ...
"Gareth's Downstairs Computer"
Post by Gareth's Downstairs Computer
A question for those who work HF mobile; do you feel that
having a loading coil and a short whip materially affects
your QSO capability, as the text books suggest, for if
not it would seem to suggest that we could all manage
with such antennae as our main base air transducers?
you have to make a compromise between /m usability and pure performance of
the antenna I have found the short jap base loaded jobs work just as well as
a centre loaded ungainly hustler when moving .......and you worry less
OK, but how do you find the QSOability in comparison to your
home antenna?
(Cue: 1/4 mile nonsense from the Mongolian Hordes of nonces)
never bother with a CQ only call people ...
j***@specsol.spam.sux.com
2018-02-07 17:58:36 UTC
Permalink
Post by Gareth's Downstairs Computer
A question for those who work HF mobile; do you feel that
having a loading coil and a short whip materially affects
your QSO capability, as the text books suggest, for if
not it would seem to suggest that we could all manage
with such antennae as our main base air transducers?
What someone feels about the laws of physics is irrelevant.
--
Jim Pennino
Catweazel
2018-02-08 10:07:25 UTC
Permalink
Post by Gareth's Downstairs Computer
A question for those who work HF mobile; do you feel that
having a loading coil and a short whip materially affects
your QSO capability, as the text books suggest, for if
not it would seem to suggest that we could all manage
with such antennae as our main base air transducers?
Last time I saw a mobile antennae it was attached to a cockroach.
HTH HAND
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Gareth's Downstairs Computer
2018-02-08 10:26:00 UTC
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Post by Catweazel
Last time I saw a mobile antennae it was attached to a cockroach.
Another apt term for describing a plod?
Catweazel
2018-02-08 17:23:46 UTC
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Post by Gareth's Downstairs Computer
Post by Catweazel
Last time I saw a mobile antennae it was attached to a cockroach.
Another apt term for describing a plod?
Not at all; this 'roach was flying.
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Gareth's Downstairs Computer
2018-02-08 18:32:33 UTC
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Post by Catweazel
Post by Gareth's Downstairs Computer
Post by Catweazel
Last time I saw a mobile antennae it was attached to a cockroach.
Another apt term for describing a plod?
Not at all; this 'roach was flying.
You mean that you were flying high after smoking
Cannabis through the roach?

J.B. Wood
2018-02-08 11:48:43 UTC
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Post by Gareth's Downstairs Computer
A question for those who work HF mobile; do you feel that
having a loading coil and a short whip materially affects
your QSO capability, as the text books suggest, for if
not it would seem to suggest that we could all manage
with such antennae as our main base air transducers?
Hello, and that's difficult to answer as you would have to do a
side-by-side comparison of two or more antennas and it gets more
complicated if ionospheric propagation is involved with constantly
varying receive signal levels. Most mobile HF antennas are electrically
short monopoles and as a result look like a capacitor in series with a
small "radiation" resistance (the conductive material of the antenna and
the vehicle body ground plane also provides some ohmic contribution).
The problem is matching the transmitter's RF output impedance (nominally
50 ohms) to the antenna feedpoint. For a longer antenna having a larger
radiation resistance we need a lot less inductance in the loading coil
and less turns means less RF power dissipation in the coil or any other
components comprising the matching network. I'm unsure what you mean by
"base air transducer" but keep in mind this discussion is essentially
about omni-directional antennas. So a mobile/fixed comparison could be
between a vehicular-mounted monopole and, say, a shunt-fed tower or an
RF-fed vertical wire supported between two structures (a common antenna
used in the U.S. for MW (AM) broadcast stations in the early 20th c.
(also aboard ocean liners like Titanic but having rotary spark-gap
transmitters). Sincerely, and 73s from N4GGO,
--
J. B. Wood e-mail: ***@hotmail.com
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