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Old August 5th 03, 02:49 PM
Jayne Medley
 
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Default new ant

What to some of you think about a Windom Ant .
Looking to put one up . Can I work all bands with no tuner like they say ?

Thanks for help



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Old August 6th 03, 07:53 AM
OK1SIP
 
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"Reg Edwards" wrote in message ...
... There is NO antenna which will allow high radiating efficiency on all
bands without a tuner. ...


Hi Reg,
the antenna at http://www.qsl.net/w5dxp/notuner.htm should cover all
bands except the topband without a device called "a tuner". Of course
it has a tuner of its sort - a set of switchable pieces of twinlead.

73 de Ivan OK1SIP
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Old August 6th 03, 11:07 AM
Reg Edwards
 
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"OK1SIP" wrote
"Reg Edwards" wrote
There is NO antenna which will allow high radiating efficiency on all
bands without a tuner. ...


Hi Reg,
the antenna at http://www.qsl.net/w5dxp/notuner.htm should cover all
bands except the topband without a device called "a tuner". Of course
it has a tuner of its sort - a set of switchable pieces of twinlead.


Hello Ivan,

I am familiar with Cecil's binary-switched variable-length feedline. We are
friends and I hope to keep things that way. ;o)

In terms of expectations, quite correctly you say "*should* cover all bands"
rather than "*will* cover all bands". Actually it doesn't cover (tune) any
band.

As a fundamental principle every tuner must have at least two variable
components because it has to match Z = R+jX which also contains two
variables. In more practical terms a tuner must have at least two knobs, for
example, one to vary L and another to vary C.

So it is impossible (or at least extrememly inconvenient) for a transmission
line to behave as a tuner because only its length can be changed. Unless, of
course, Cecil can invent a way of varying its impedance Zo between, say, 100
and 600 ohms.

But bearing in mind Cecil's primary objective in using a 'tuner' is to
provide a load which will keep the transmitter happy, without regard to SWR
on the variable-length feedline, his arrangement is successful. It is
necessary only for the transmitter to be happy provided its load indicator
has a reading which does not exceed much above 1.5 to 1. (SWR).

Whether or not the station operator is happy using a tuner with one of the
knobs missing is another matter.

The behaviour/performance of Cecil's 'tuner' can be very accurately modelled
using program DIPOLE3. Download in a few seconds from website below. Just
vary frequency or line length and watch the line input impedance.
----
=======================
Regards from Reg, G4FGQ
For Free Radio Design Software
go to http://www.g4fgq.com
=======================







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Old August 6th 03, 03:09 PM
W5DXP
 
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Reg Edwards wrote:
But bearing in mind Cecil's primary objective in using a 'tuner' is to
provide a load which will keep the transmitter happy, without regard to SWR
on the variable-length feedline, ...


Since I developed this antenna, I have upgraded from an IC-706
to an IC-756PRO which has a built-in autotuner which will match most anything
with a 50 ohm SWR of 3:1 or less. So my variable length feedline is ideal for
hams with built-in autotuners who are having trouble matching high SWR's.
--
73, Cecil http://www.qsl.net/w5dxp



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Old August 8th 03, 09:54 AM
W5DXP
 
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Jayne Medley wrote:
What to some of you think about a Windom Ant .
Looking to put one up . Can I work all bands with no tuner like they say ?


The original (true) Windom uses a single-wire feedline and requires
a matching network.
--
73, Cecil http://www.qsl.net/w5dxp



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Old August 8th 03, 06:04 PM
Art Unwin KB9MZ
 
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"Reg Edwards" wrote in message ...
"Jayne Medley" wrote
What to some of you think about a Windom Ant .
Looking to put one up. Can I work all bands
with no tuner like they say ?

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

Jayne,

No you can't.

Who are "they" anyway ? Antenna salesmen ? Old-wives ?

There is NO antenna which will allow high radiating efficiency on all bands
without a tuner.


Just out of interest but what do you consider to be the low limit of a
" high radiating efficiency" for the HF bands? With a tuner,
without a tuner?
Art





In fact, there is NO antenna which will allow high radiating efficiency on
all bands even WITH a tuner, taking radiation pattern into account!

And to complete the depressing story there is no commercial tuner which will
cover all bands from 160 to 10 meters.

To work all bands efficiently, in any geographical direction, you need an
antenna farm containing at least 3 separate antennas, a reasonable ground
radial system, a number of transmission lines, with availability in the
shack of 3 different tuners.

However, the original Windom, which must have first been used 65 or 75 years
ago, well before it acquired a name from the first person to take the
trouble to describe it in a ham magazine, is a good all round performer. It
has to be - it's so simple.

The original Windom is a half-wave dipole, resonant at the the design
frequency, fed by a single wire transmission line of random length, the line
being tapped off-centre into the dipole. Radiation from the single-wire
feedline is intentional. Only a moderate sort of ground-radial system is
needed. But a tuner is needed to match any particular band to a 50-ohm
transmitter. In the olden-days a 50-ohm transmitter was unheard of.

Relatively modern versions of Windoms are bugged by the sales gimmicks of
supposedly balanced twin feedlines and baluns which do nothing but degrade
efficiency compared with the original simplicity. There is just as much
radiation from the off-centre-fed twin feedline. Antenna salesmen don't
mention the subject.

For performance of the original Windom, download in a few seconds and run
immediate;y program WINDOM2 from website below
----
=======================
Regards from Reg, G4FGQ
For Free Radio Design Software
go to http://www.g4fgq.com
=======================

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Old August 8th 03, 07:04 PM
Reg Edwards
 
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"Art Unwin wrote
"Reg Edwards" wote
"Jayne Medley" wrote
What to some of you think about a Windom Ant .
Looking to put one up. Can I work all bands
with no tuner like they say ?


No you can't.

Who are "they" anyway ? Antenna salesmen ? Old-wives ?

There is NO antenna which will allow high radiating efficiency on all

bands
without a tuner.


Just out of interest but what do you consider to be the low limit of a
" high radiating efficiency" for the HF bands? With a tuner,
without a tuner?


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

Ask the Antenna salesmen and Old-wives who Jayne listens to.
---
Reg.


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Old August 8th 03, 07:40 PM
Richard Clark
 
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On Fri, 8 Aug 2003 18:04:03 +0000 (UTC), "Reg Edwards"
wrote:
"Art Unwin wrote
"Reg Edwards" wote
There is NO antenna which will allow high radiating efficiency on all
bands without a tuner.


Just out of interest but what do you consider to be the low limit of a
" high radiating efficiency" for the HF bands? With a tuner,
without a tuner?


Ask the Antenna salesmen and Old-wives who Jayne listens to.
---
Reg.

he did....
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Old August 8th 03, 08:23 PM
Reg Edwards
 
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Ask the Antenna salesmen and Old-wives who Jayne listens to.
---

Tricky Dick said - he did ....

Hi Tricky Dicky, you've been keeping a low profile just lately. What
tempted *you* above the parapet?




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