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H. Adam Stevens, NQ5H April 5th 04 12:30 PM


"Dan Richardson @mendolink.com" ChangeThisToCallSign wrote in message
...
On Sun, 4 Apr 2004 22:12:24 -0500, "H. Adam Stevens, NQ5H"
wrote:

You just can't beat a resonant antenna for radiation.


Eh? You mean a 1¼-wave (non-resonate) dipole radiates less than a
¼-wave resonate dipole?

Strange in that a 1¼-wave dipole has 3 dBd gain.

Danny, K6MHE


Antenna resonance implies a purely resistive impedance at the feed point.
Both 1/2 wave and 3/2 wave dipoles are resonant.
I don't know what a "1/4-wave resonate dipole" is.
A dipole is 1/2 wavelength long at it's fundamental resonant frequency.
"Gain" is merely a re-distribution of the radiation pattern.
73
H.
NQ5H



H. Adam Stevens, NQ5H April 5th 04 12:49 PM


"Bill Turner" wrote in message
...
On Sun, 4 Apr 2004 22:12:24 -0500, "H. Adam Stevens, NQ5H"
wrote:

Tuners squander AT BEST 1 or 2 db.


__________________________________________________ _______

Nonsense. At 1500 watts, a tuner which "squandered" 1 db would be
dissipating about 300 watts and would soon be a smoking mess.

2 db I don't even want to think about.


--
Bill, W6WRT
QSLs via LoTW

Nonsense huh?
OK
Load up your rig at 1500 watts key down with a tuner.
Measure the tuner's temperature.

Icom specifies the insertion loss for the tuners in my 756PROII and PW1.
Icom claims less than one decibel. (After tuning)
The loss is easy to measure and at 1KW it is indeed well over 100 watts
warming the PW1's innards when it could be radiating away from my SteppIR.
So I leave the tuners out of line and adjust the antenna for SWR = 1:1.
73
H.
NQ5H



Dan Richardson April 5th 04 01:26 PM

On Mon, 5 Apr 2004 06:30:15 -0500, "H. Adam Stevens, NQ5H"
wrote:


"Dan Richardson @mendolink.com" ChangeThisToCallSign wrote in message
.. .
On Sun, 4 Apr 2004 22:12:24 -0500, "H. Adam Stevens, NQ5H"
wrote:

You just can't beat a resonant antenna for radiation.


Eh? You mean a 1¼-wave (non-resonate) dipole radiates less than a
¼-wave resonate dipole?

Strange in that a 1¼-wave dipole has 3 dBd gain.

Danny, K6MHE


Antenna resonance implies a purely resistive impedance at the feed point.
Both 1/2 wave and 3/2 wave dipoles are resonant.
I don't know what a "1/4-wave resonate dipole" is.
A dipole is 1/2 wavelength long at it's fundamental resonant frequency.
"Gain" is merely a re-distribution of the radiation pattern.
73
H.
NQ5H


Sorry.. a typo should be 1¼-wave non-resonte dipole.

Danny


Dan Richardson April 5th 04 01:30 PM

On Mon, 05 Apr 2004 06:02:56 GMT, "Jerry Martes"
wrote:


"Dan Richardson @mendolink.com" ChangeThisToCallSign wrote in message
.. .
On Sun, 4 Apr 2004 22:12:24 -0500, "H. Adam Stevens, NQ5H"
wrote:

You just can't beat a resonant antenna for radiation.


Eh? You mean a 1¼-wave (non-resonate) dipole radiates less than a
¼-wave resonate dipole?

Strange in that a 1¼-wave dipole has 3 dBd gain.

Danny, K6MHE


Danny

Do antennas have gain or do they have directivity?

Jerry


Both

Danny


Dan Richardson April 5th 04 01:33 PM

On Mon, 5 Apr 2004 06:30:15 -0500, "H. Adam Stevens, NQ5H"
wrote:


"Dan Richardson @mendolink.com" ChangeThisToCallSign wrote in message
.. .
On Sun, 4 Apr 2004 22:12:24 -0500, "H. Adam Stevens, NQ5H"
wrote:

You just can't beat a resonant antenna for radiation.


Eh? You mean a 1¼-wave (non-resonate) dipole radiates less than a
¼-wave resonate dipole?

Strange in that a 1¼-wave dipole has 3 dBd gain.

Danny, K6MHE


Antenna resonance implies a purely resistive impedance at the feed point.
Both 1/2 wave and 3/2 wave dipoles are resonant.
I don't know what a "1/4-wave resonate dipole" is.
A dipole is 1/2 wavelength long at it's fundamental resonant frequency.
"Gain" is merely a re-distribution of the radiation pattern.
73
H.
NQ5H


Well, I'll try it again..... still a typo I meant to say "a ½-wave
resonate dipole".. Sorry

In other words I press Alt+172 instead of Alt+171

Danny


Cecil Moore April 5th 04 03:59 PM

Jerry Martes wrote:

Do antennas have gain or do they have directivity?


From Balanis: "Although the gain of an antenna is closely
related to the directivity, gain is a measure that takes into
account the efficiency of the antenna as well as the
directional properties of the antenna, and it is therefore
controlled only by the pattern."
--
73, Cecil, W5DXP



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JDer8745 April 5th 04 04:09 PM

Someone sed,

"You just can't beat a resonant antenna for radiation."
===================

PHOOEY! Some of the best antennas are NOT resonant, and shouldn't be.

I use my 130-ft doublet on 40 m where it is one wavelength long. Has
theoreitical gain of about 1.8 dB. This is NOT a resonant antenna.

73 de Jack, K9CUN

JDer8745 April 5th 04 04:12 PM

"Do antennas have gain or do they have directivity?"
============================
What a wierd question! These are not mutally exclusive properties.

73 de Jack, K9CUN



Cecil Moore April 5th 04 04:46 PM

H. Adam Stevens, NQ5H wrote:

"Cecil Moore" wrote:
Maybe not, but you can equal them. A tuned transmission line resonates
the antenna system.


When you get a lossless line. And the antenna still isn't resonant.


So what? If you move off the resonant frequency, your antenna still isn't
resonant. I'd rather have a resonant antenna system on many frequencies
and many bands than an antenna system resonant on only one frequency.

IF impedance transformation is necessary, use a transmission line
as the transformer. :-)


Not the least lossy approach.
Matched impedance = max power transfer.


Depends upon how much money you want to sink into your coax. Open-wire
line with an SWR of 10:1 will beat RG-213 in the loss department on 80m.
It takes 9913 to equal the performance of open-wire line with an SWR of
10:1 on 80m and 9913 costs about three times as much as open-wire line.

And with open-wire line, one can enjoy all eight HF bands immediately,
and not have to spend two days cutting and trying a fan dipole.
--
73, Cecil, W5DXP



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Robert Lay W9DMK April 5th 04 04:51 PM

On Sun, 04 Apr 2004 21:12:51 -0700, Bill Turner
wrote:

On Sun, 4 Apr 2004 22:12:24 -0500, "H. Adam Stevens, NQ5H"
wrote:

Tuners squander AT BEST 1 or 2 db.


_________________________________________________ ________

Nonsense. At 1500 watts, a tuner which "squandered" 1 db would be
dissipating about 300 watts and would soon be a smoking mess.

2 db I don't even want to think about.


--
Bill, W6WRT
QSLs via LoTW


Dear Bill,
Your figures and your terminology are 100% correct. Anyone who has an
amplifier capable of delivering 1500 watts of carrier power,
continuously, for any appreciable amount of time would, indeed,
encounter a smoking mess. Fortunately, hams don't usually run that
kind of power, but it does explain why so many tuners found at
hamfests have very obvious damage to the variable inductor coil.


Bob, W9DMK, Dahlgren, VA
http://www.qsl.net/w9dmk


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