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Old February 23rd 16, 12:25 AM posted to rec.radio.amateur.antenna,uk.radio.amateur
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On 22/02/2016 21:26, Custos Custodum wrote:
"gareth" wrote in
:

"Issued with Damages ..." wrote in message
...
On 22/02/2016 19:08, wrote:
In rec.radio.amateur.antenna gareth
wrote:
ATU setting up seems to be a matter of suck-it-and-see, even
on the part of the auto ATUs (which are made for for
CBers-masquerading-as-radio-amateurs
because _REAL_ radio amateurs have no qualms about twiddling knobs
themselves)
REAL radio amateurs know that the best place for an antenna tuner is
at the base of the antenna, which makes "twiddling knobs" a bit
difficult.
I wonder if anyone takes a more scientifc approach by measurement
and then
calculation, such as by Smith Chartification?
Such would require increased complexity in the hardware and software
and also require periodic calibration.
Ever heard of the KISS principal?

Keep It Stupidly Simple ... ???


Jim, I'd killfiled Jim Pendulumino because he's like a Yank version of
Brian Reay M3OSN.

That is, always pooh-poohing, always sneering. always free with rude
comments and
without a kind word for anyone.


Sounds like many "Class A's" hereabouts.

naw...professional radio telephone class B users ......

--
Rescue an animal or shut up about it ...
Never buy a French car ...
Buying something is not the problem. The problem comes when we believe,
for that moment, that the object we’re buying is going to make us happy.
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Old February 23rd 16, 12:42 AM posted to rec.radio.amateur.antenna,uk.radio.amateur
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On 22/02/2016 20:53, gareth wrote:
"Issued with Damages ..." wrote in message
...
On 22/02/2016 19:08, wrote:
In rec.radio.amateur.antenna gareth wrote:
ATU setting up seems to be a matter of suck-it-and-see, even
on the part of the auto ATUs (which are made for for
CBers-masquerading-as-radio-amateurs
because _REAL_ radio amateurs have no qualms about twiddling knobs
themselves)
REAL radio amateurs know that the best place for an antenna tuner is
at the base of the antenna, which makes "twiddling knobs" a bit
difficult.
I wonder if anyone takes a more scientifc approach by measurement and
then
calculation, such as by Smith Chartification?
Such would require increased complexity in the hardware and software and
also require periodic calibration.
Ever heard of the KISS principal?

Keep It Stupidly Simple ... ???


Jim, I'd killfiled Jim Pendulumino because he's like a Yank version of Brian
Reay M3OSN.

That is, always pooh-poohing, always sneering. always free with rude
comments and
without a kind word for anyone.



good for you....I love people like that....entertaining

--
Rescue an animal or shut up about it ...
Never buy a French car ...
Buying something is not the problem. The problem comes when we believe,
for that moment, that the object we’re buying is going to make us happy.
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Old March 5th 16, 03:04 AM posted to rec.radio.amateur.antenna,uk.radio.amateur
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Posts: 45
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"gareth" wrote in message ...



I wonder if anyone takes a more scientifc approach by measurement and then
calculation, such as by Smith Chartification?

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

Yes, the world's Navies do. I worked for the US Navy for many years so I
know much of what they do.

On HF, a few transmissions are made on whips with base-mounted couplers to
bring the whip to resonance.

The remainder are by broadband antennas (2 - 6, 4 - 12, 10 - 30 MHz) These
broadband antennas are fed through matching networks that had to bring them
within the 3:1 circle on the Smith Chart. During inspections, we had to
sweep them and we reported any that failed. (Some of our tasks were
find-and-fix, most were not.)

We used an Anritsu something-or-other as the sweeper. It had ten memories,
so we could store profiles for multiple antenna ranges. Although I want one
for home, they're far too expensive for me. I have an AA-54 from RigExpert.
It's the Poor Man's Anritsu.

"Sal"
(KD6VKW)

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Old March 5th 16, 04:23 PM posted to rec.radio.amateur.antenna,uk.radio.amateur
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"Sal M. O'Nella" wrote in message
...

The remainder are by broadband antennas (2 - 6, 4 - 12, 10 - 30 MHz)
These broadband antennas are fed through matching networks that had to
bring them within the 3:1 circle on the Smith Chart. During inspections,
we had to sweep them and we reported any that failed. (Some of our tasks
were find-and-fix, most were not.)


Interesting. I wonder if that could be the solution to amateur
installations,
a set of broadband dipoles, but perhaps swept smithchartwise to better
than 2:1?





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Old March 14th 16, 05:55 AM posted to rec.radio.amateur.antenna,uk.radio.amateur
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"gareth G4SDW GQRP #3339" wrote in message
...

"Sal M. O'Nella" wrote in message
...

The remainder are by broadband antennas (2 - 6, 4 - 12, 10 - 30 MHz) These
broadband antennas are fed through matching networks that had to bring
them within the 3:1 circle on the Smith Chart. During inspections, we had
to sweep them and we reported any that failed. (Some of our tasks were
find-and-fix, most were not.)


Interesting. I wonder if that could be the solution to amateur
installations,
a set of broadband dipoles, but perhaps swept smithchartwise to better
than 2:1?

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

Quite on target.

Apropos of that, I fielded an inquiry last week from a fellow in our club
who wants some help putting up a 125' long-wire for 30m operation. I've
tried to convince him that random-length wires are tricky and any end-fed
antenna can be a matching nightmare but he insists he still wants to try it.
I've never tried long-wire for transmit, so ... might as well play. He
would like to go coax from the shack to an end-feed about 25 feet aloft.

I've been debating with myself whether I could do a Smith chart at the feed
point and calculate the required component(s) to be placed at the feed. If
he's only going to use it for one frequency (essentially, since that band is
so narrow), I just have one point on the chart to move with one or more
reactive component(s). The big drawback, as I see it, is there is no ground
for the shield. I have not yet investigated matching techniques for this,
although I do recall reading about a so called 9:1 balun. More research
needed.

Although I sure as heck can read a Smith Chart and tell you whether the
tested frequencies fall within the 3:1 VSWR circle, I've never gone the
other way -- taking a "bad" antenna and bringing it to good health, IRT its
feed-point impedance. At work, as described above, we merely validated the
continuing suitability of each antenna for its intended freq range.

"Sal"
(KD6VKW)

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Old March 30th 16, 09:36 PM posted to rec.radio.amateur.antenna
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On Monday, February 22, 2016 at 9:41:30 AM UTC-8, gareth wrote:
ATU setting up seems to be a matter of suck-it-and-see, even
on the part of the auto ATUs (which are made for for
CBers-masquerading-as-radio-amateurs
because _REAL_ radio amateurs have no qualms about twiddling knobs
themselves)

I wonder if anyone takes a more scientifc approach by measurement and then
calculation, such as by Smith Chartification?


Sure, I use a nice Smith chart program (unfortunately no longer available) to figure out optimized matching networks for antennas and other things. I'd add, there's an old "Ham Radio" article (actually two articles), "The Antenna-Transmission Line Analog," from April+May, 1977, that can help you understand what's going on in wire antennas (if you can manage to digest the article, anyway). Some people pooh-pooh Smith charts, perhaps saying that computers can figure all that out for you, but I find the visualization quite helpful.

73, Tom
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