Has anybody given any thought to what an antenna tuner of any kind
adds to your enjoyment in ham life. I have the MFJ 3kw tuner
with the roller inductor and differential capacitor and what a
charmer it is. I dont worry about my inverted dipoles mostly
Vertical polarized. I just crank up on any freqcy between
1.6 and 30 mhz and dont give a dam about gain or lack of same.
It just makes life so ez to do it that way. Why you ask.
Because it protects the ic751's output stages. Think of the
tuner as a RF SUCKER, it just sucks all the dangerous stuff
out of the rig and puts it in the tuner. How much of that
power gets finally radiated I could care less. I work
mostly on MARS freqcys and none of them are inside the ham bands
so this tuner serves me well.
Joe/KH6JF/ABM6JF


************************************************** **
* Ham KH6JF AARS/MARS ABM6JF QCWA WW2 VET WD RADIO *
************************************************** **


On Thu, 8 Apr 2004, Reg Edwards wrote:

Richard Clark,

I fully support your "All antennas have zero gain" campaign.

Why not join the "There's no such thing as an SWR meter" campaign?
----
Reg, G4FGQ

On Thu, 8 Apr 2004 20:03:15 +0000 (UTC), "Reg Edwards"
wrote:

Richard Clark,

I fully support your "All antennas have zero gain" campaign.

Why not join the "There's no such thing as an SWR meter" campaign?
----
Reg, G4FGQ

Hi Reg,

Because all mine have lines through them.

73's
Richard Clark, KB7QHC

On Thu, 8 Apr 2004 11:36:45 -1000, Joseph Fenn wrote:
I just crank up on any freqcy between
1.6 and 30 mhz and dont give a dam about gain or lack of same.
It just makes life so ez to do it that way.

Hi Joe,

That's the best advice we can offer:
Don't worry 'bout the things you can't change.

73's
Richard Clark, KB7QHC

Has anybody given any thought to what an antenna tuner of any kind
adds to your enjoyment in ham life.

Joseph, You bet, just search the archives of this group. Tuner or not,
resonant or non-resonant you will find many informative and entertaining
discussions. You should find that a bunch of folks have thought about tuners
and their benefit.


73 Gary N4AST

Someone said:

"There is no gain in any antenna. "
=========================

This is absolute BS. All u hv to do is read the catalogs fm Cushcraft, MFJ,
HyGain, etc. ALL of their antennas have gain! (Except the ones which don't.)

73 e Jack, K9CUN

Reg Edwards wrote:

Richard Clark,

I fully support your "All antennas have zero gain" campaign.

IMO applying the word 'Gain' to an antenna is misuse of the word 'gain'.

Beam forming antennas do concentrate the RF energy into an angle less
than 2*Pi steradians [Hemisphere] but the total energy concentrated is
still the power applied to the antenna minus losses. The far field from
a beam forming antenna is more intense than from an isotropic antenna.

Maybe the better term is to quote the solid angle at the 1/2 power
points in the E and H plane as a figure of merit. Example: antenna A has
a 1/2 power beam width of 2500 square degrees while antenna B has a 1/2
power beam width of 1800 square degrees.


Why not join the "There's no such thing as an SWR meter" campaign?
----
Reg, G4FGQ



Ah! But there are techniques for measuring TRUE VSWR!! [Not my little
Daiwa 101C or even the trusty Bird.]

Nope, I used to measure TRUE VSWR [in 1958] using a General Radio
Slotted Line with moveable probe!! I've forgotten the plotting details
but the answer came from plotting the response over 1/4 wavelength on a
SMITH Chart. Ain't cheap but it was accurate.

Seriously, I wonder if any readers recall the details of measuring and
plotting based on the GR Slotted Line?

Next question: where do I get a 160 meter 1/2 wavelength 50 ohm slotted
line?

Dave Shrader wrote:
IMO applying the word 'Gain' to an antenna is misuse of the word 'gain'.

Maybe, but I'll bet it's a losing cause. :-)

Next question: where do I get a 160 meter 1/2 wavelength 50 ohm slotted
line?

I've made slots in RG-213 with an Exacto knife. How much spare time
do you have?
--
73, Cecil, W5DXP



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On Fri, 09 Apr 2004 09:02:21 -0700, Bill Turner
wrote:

On Thu, 08 Apr 2004 18:35:22 GMT, Richard Clark
wrote:

All simply an argument for engineering through democratic vote.

_________________________________________________ ________

Not at all. They are arguments for using common language. Your attempt
to redefine antenna gain - a term in use for decades - clouds an issue
which is actually straightforward. Naughty boy!

C'mon Bill,

Redefine antenna gain? Where? I simply removed the option of calling
it absolute gain that is more in the province of active amplifiers not
passive lenses. The thread is already 28 posts too long - it isn't
rocket surgery.

73's
Richard Clark, KB7QHC

In article fxzdc.143$cD2.12959@attbi_s51,
Dave Shrader wrote:

IMO applying the word 'Gain' to an antenna is misuse of the word 'gain'.

Since this particular terminology has been used in this way in both
amateur and professional antenna literature for more decades than I've
been alive (I'm pushing 50) I think you're tilting at windmills to try
to eliminate it, or to declare it "misuse".

I personally prefer to refer to what an antenna delivers as
"directional gain", to distinguish it from the sort of "more RF out
than RF in" power gain that an amplifier delivers. From the point of
view of someone trying to deliver a specified amount of power to a
receiver in a specified direction, the two types of "gain" can be
interchanged to a large degree.

Yes, they're distinct, and we need to remember the distinctions, but
they can be traded-off against one another in many common sorts of
calculations.

[At the risk of re-opening a topic of contention, I'll posit that the
use of the term "gain" to refer to both amplifier power gain and to
antenna directional gain is somewhat similar in spirit to the use of
the term "resistance" to refer to both dissipative and nondissipative
impedances. Each is a single term, referring to two different
phenomena which can under many circumstances behave in ways which can
look equivalent from a particular point of view.]

Next question: where do I get a 160 meter 1/2 wavelength 50 ohm slotted
line?

Go down to your nearest abandoned rust-belt factory that has a large
brick or concrete chimney, wrap the chimney with sheet tin (leaving a
slot), and drop a suitable-sized silver-plated cast-iron sewer pipe
down the center. Run your probe up and down the chimney on a huge
pulley.

It'll probably be tricky to couple this to the antenna and feedline,
though. I don't think even Andrews makes a heliax connector quite
this large.

grin

--
Dave Platt AE6EO
Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

Bill Turner wrote:

SNIP

Not at all. They are arguments for using common language. Your attempt
to redefine antenna gain - a term in use for decades - clouds an issue
which is actually straightforward. Naughty boy!

--
Bill, W6WRT
QSLs via LoTW


Hold on Bill!! I posit a 6 element long john yagi in free space with
1500 watts at the feedpoint.

If I assume 100% efficiency, no losses in the antenna and antenna
materials, and then calculate the power in the surface of the resulting
pattern do I not get 1500 watts?? That's 0 dB gain!!!

This is common language and correct Physics.

THE ANTENNA HAS NO GAIN !!!!!!!

Now, for the sake of accuracy the antenna PATTERN will have a different
pattern from a dipole or an isotropic antenna. The antenna pattern
yields a field intensity that is greater than the reference antenna's
pattern.

So, the correct gain terminology must speak in terms of resulting
PATTERN not the antenna.

'Antenna gain' is both loose and incorrect language notwithstanding
advertising and marketing claims. 'Antenna Pattern Gain' or 'Directional
Gain' is correct language.

"Dave Shrader" wrote -
Seriously, I wonder if any readers recall the details of measuring and
plotting based on the GR Slotted Line?

-------------------------------------------------------

What's 'GR' ? Never heard of it.

Never-to-be-forgotten, I first measured SWR on a laboratory bench slotted
line in the town of Stockport near Manchester around February 1944. V1's and
V2's, Hitler's secret weapons, were falling on London and S.E. England. The
1000-bomber raids by the RAF on German towns and cities, the fire storms
directed by Air Marshal Bomber Harris, were building up with an ever
increasing ferocious intensity. One night 110 heavy bombers failed to return
to base. The death toll in Europe and Russia had already passed the 15
million mark.

I remember it was raining at the time. It always rains in Manchester.

There were two simple relative voltage measurements spaced 1/4-wavelengths
apart. Values of Zo, Zg, Zt and Gamma were quite irrelevant. The only
mathematical equation was SWR = V1/V2. And that's all there was to it!

So began my radio education.
----
Reg, G4FGQ

Reg

Did General radio ever make a slotted line?



"Reg Edwards" wrote in message
...

"Dave Shrader" wrote -
Seriously, I wonder if any readers recall the details of measuring and
plotting based on the GR Slotted Line?

-------------------------------------------------------

What's 'GR' ? Never heard of it.

Never-to-be-forgotten, I first measured SWR on a laboratory bench slotted
line in the town of Stockport near Manchester around February 1944. V1's
and
V2's, Hitler's secret weapons, were falling on London and S.E. England.
The
1000-bomber raids by the RAF on German towns and cities, the fire storms
directed by Air Marshal Bomber Harris, were building up with an ever
increasing ferocious intensity. One night 110 heavy bombers failed to
return
to base. The death toll in Europe and Russia had already passed the 15
million mark.

I remember it was raining at the time. It always rains in Manchester.

There were two simple relative voltage measurements spaced 1/4-wavelengths
apart. Values of Zo, Zg, Zt and Gamma were quite irrelevant. The only
mathematical equation was SWR = V1/V2. And that's all there was to it!

So began my radio education.
----
Reg, G4FGQ

Reg Edwards wrote:
"Dave Shrader" wrote -

Seriously, I wonder if any readers recall the details of measuring and
plotting based on the GR Slotted Line?


-------------------------------------------------------

What's 'GR' ? Never heard of it.

I mentioned General Radio earlier in the post. General Radio AKA GR.

Sorry for the confusion.

Dave

You made a comment about the details of calculating load impedance using a
slotted line. I'm curious to know if anyone has built a slotted line at
home. It would be interesting to me to have a slotted line for about
125MHz.

It seems that if you could measure the voltage mins along a line
terminated by the load to be evaluated and the location of the min with a
short ckt to replace that load. That reading, together with the Vmax/Vmin
could get you close to the load impedance with a Smith Chart (I think)

Jerry




"Dave Shrader" wrote in message
news:fxzdc.143$cD2.12959@attbi_s51...
Reg Edwards wrote:

Richard Clark,

I fully support your "All antennas have zero gain" campaign.

IMO applying the word 'Gain' to an antenna is misuse of the word 'gain'.

Beam forming antennas do concentrate the RF energy into an angle less
than 2*Pi steradians [Hemisphere] but the total energy concentrated is
still the power applied to the antenna minus losses. The far field from
a beam forming antenna is more intense than from an isotropic antenna.

Maybe the better term is to quote the solid angle at the 1/2 power
points in the E and H plane as a figure of merit. Example: antenna A has
a 1/2 power beam width of 2500 square degrees while antenna B has a 1/2
power beam width of 1800 square degrees.


Why not join the "There's no such thing as an SWR meter" campaign?
----
Reg, G4FGQ



Ah! But there are techniques for measuring TRUE VSWR!! [Not my little
Daiwa 101C or even the trusty Bird.]

Nope, I used to measure TRUE VSWR [in 1958] using a General Radio
Slotted Line with moveable probe!! I've forgotten the plotting details
but the answer came from plotting the response over 1/4 wavelength on a
SMITH Chart. Ain't cheap but it was accurate.

Seriously, I wonder if any readers recall the details of measuring and
plotting based on the GR Slotted Line?

Next question: where do I get a 160 meter 1/2 wavelength 50 ohm slotted
line?

Jerry Martes wrote:
I'm curious to know if anyone has built a slotted line at home.

Jerry, if you use balanced feedline, you don't need a slotted
line. You can just use an inductive pickup loop with a 1N34A
diode rectifier circuit. Whatever you read on your DC voltmeter
as maximum and minimum values will yield the SWR. That's another
advantage of ladder-line.
--
73, Cecil, W5DXP



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Bill

How does a person measure the gain of an antenna?

Jerry


"Bill Turner" wrote in message
...
On Fri, 09 Apr 2004 19:15:05 GMT, Dave Shrader
wrote:


So, the correct gain terminology must speak in terms of resulting
PATTERN not the antenna.

Ok, but the pattern is created by the antenna. If the pattern has gain,
most of us would think of the antenna having gain.


'Antenna gain' is both loose and incorrect language notwithstanding
advertising and marketing claims.

If enough people use a term incorrectly, it becomes correct, like it or
not. The word "lite" as in "lite beer" did not exist a couple of
decades ago. Some advertiser decided to use it in place of "light" and
despite opposition from linguistic purists, it is now correct. "Antenna
gain" may not be correct in the eyes of a purist, but if the masses use
it and know what it means...

--
Bill, W6WRT
QSLs via LoTW

"Bill Turner" wrote in message
...
On Sat, 10 Apr 2004 13:40:51 GMT, "Jerry Martes"
wrote:

Bill

How does a person measure the gain of an antenna?

Jerry

__________________________________________________ _______

Carefully, I would hope.

--
Bill, W6WRT
QSLs via LoTW

I'll be carefull if you'll tell me how to do it.

Jerry

On Sat, 10 Apr 2004 08:37:09 -0700, Bill Turner
wrote:
Bill

How does a person measure the gain of an antenna?

Jerry

Carefully, I would hope.

Hi Bill,

Your response hardly carries the water for an argument supporting gain
being commonly distinct from directivity.

To answer Jerry's question (he probably already knows how) requires
the total integration of all power emitted by the radiator - not an
easy task (as would confirm Bill's sparse reply) and then measuring
power emitted within small volumes (solid angles of sub-radian
dimension) to compare against the whole.

The most distinctive point to observe about this "gain" is that almost
all the power radiated is lost - "almost" being a patronizing term. A
simple thought problem will reveal this sad fate.

Let us presume you are transmitting 100W with 100% efficiency. Now,
lets further presume that the entire population of the planet is
monitoring you with S-9 readability. That is (let's be generous), 10
Billion receivers. What is the net result of this massive
communication in system efficiency?
0.5%

The antenna in the most perfect of circumstances exhibits an absolute
loss of 99.5W and I could easily bet no one here even pretends to
approach 0.000001% of this.

Now, tell me about GAIN. :-)

73's
Richard Clark, KB7QHC

Jerry Martes wrote:
How does a person measure the gain of an antenna?

For 75m mobile antenna shootouts, we have measured the field
strength of the ground wave in the far field compared to
a reference antenna.
--
73, Cecil, W5DXP



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Jerry Martes wrote:

Bill

How does a person measure the gain of an antenna?

Jerry


In the olden days, 1985, on an outdoor range, we would calculate the
gain from measuring the 1/2 power points on an antenna range at 1000
wavelengths minimum between antennas and find the 1/2 power [-3 dB]
angles in the horizontal and vertical planes. [Note C-Band and S-Band]

Knowing the angles the 'Gain' is calculated by dividing 41259 by the
product of the horizontal and vertical angles corresponding to the 1/2
power point. [Note: 41259 is the surface of the sphere measured in
square steradians.]

On the indoor anechoic chamber we measured the input power at the feed
point through a -10 dB splitter and the radiated power density at a
target point in the far wall. Then ran the basic calculation.
[Classified Military Program]

Aligning those 12 foot diameter dishes inside the anechoic chamber was
'fun'.

Even after managing two antenna ranges and being party to 'antenna gain'
measurements for more than 10 years of my professional life, I still
have fun touting that antennas have 'No Gain'.

"Richard Clark" wrote in message
...
On Sat, 10 Apr 2004 08:37:09 -0700, Bill Turner
wrote:
Bill

How does a person measure the gain of an antenna?

Jerry

Carefully, I would hope.

Hi Bill,

Your response hardly carries the water for an argument supporting gain
being commonly distinct from directivity.

To answer Jerry's question (he probably already knows how) requires
the total integration of all power emitted by the radiator - not an
easy task (as would confirm Bill's sparse reply) and then measuring
power emitted within small volumes (solid angles of sub-radian
dimension) to compare against the whole.

The most distinctive point to observe about this "gain" is that almost
all the power radiated is lost - "almost" being a patronizing term. A
simple thought problem will reveal this sad fate.

Let us presume you are transmitting 100W with 100% efficiency. Now,
lets further presume that the entire population of the planet is
monitoring you with S-9 readability. That is (let's be generous), 10
Billion receivers. What is the net result of this massive
communication in system efficiency?
0.5%

The antenna in the most perfect of circumstances exhibits an absolute
loss of 99.5W and I could easily bet no one here even pretends to
approach 0.000001% of this.

Now, tell me about GAIN. :-)

73's
Richard Clark, KB7QHC

Wow Richard, measuring antenna gain sounds complicated. I never was good
at calculus.

Jerry

On Sat, 10 Apr 2004 20:12:08 GMT, "Jerry Martes"
wrote:
Wow Richard, measuring antenna gain sounds complicated. I never was good
at calculus.

Hi Jerry,

That's for software to do.

73's
Richard Clark, KB7QHC

On Sun, 11 Apr 2004 08:36:19 -0700, Bill Turner
wrote:
For ham radio purposes, antenna gain and
directivity are essentially interchangeable.

Close enough for Government work.

On the other hand, if you try that on your dissertation for your PhD in
physics, you may end up working at McDonalds.

Hi Bill,

My first assignment out of Metrology school was in Charleston S. C.
loaned to the SeaBees (because my ship was still in Rota Spain). They
took full stock of my million dollar training and found I was
qualified to dig ditches in the clay banks along the Charles river.
They were impressed I knew which end of the shovel went into the
ground and we became fast friends (made me an honorary SeaBee).

Navy motto, "those that work hard together, play hard together" (I
had already learned that from my Pig-boat buddies.)

73's
Richard Clark, KB7QHC

On Sat, 10 Apr 2004 17:29:56 GMT, Dave Shrader
wrote:

Knowing the angles the 'Gain' is calculated by dividing 41259 by the
product of the horizontal and vertical angles corresponding to the 1/2
power point. [Note: 41259 is the surface of the sphere measured in
square steradians.]

I'm sure that most are aware that a sphere has 4 Pi steradians, but
you've lost me with your number 41259, and what is a "square"
steradian? I've never heard of such a thing.
Bob, W9DMK, Dahlgren, VA
http://www.qsl.net/w9dmk

Bill

First - I want to be clear that I have absolutely no problem with using
the term GAIN for describing antenna performance.
I did think had not been established, in this thread, that an antena's
gain has to be referanced to some standard antenna, like a dipole or
theoretical radiator like 'isotropic'. I'd submit that, what we refer to as
antenna gain could be more accurately be called 'specific gain'. I also
tink that the term Directivity clears up any misunderstanding about what can
be done to improve an antenna's performance. And, I realize that my
thinking about Gain and about Directivity dont imply that anyone needs to
exclude either from their vocabulary

I suspect my caution about antenna gain stems from reading specs that
display extremely high "gain" numbers while the antennas are actually quite
ordinary.

Jerry


"Bill Turner" wrote in message
...
On Sat, 10 Apr 2004 15:59:56 GMT, "Jerry Martes"
wrote:

I'll be carefull if you'll tell me how to do it.

Jerry

__________________________________________________ _______

Only one "l" in careful Jerry, not a good start. :-)


1. Decide on your reference, most likely a dipole.

2. Measure the field strength of the dipole in its most favored
direction.

3. Measure the field strength of the antenna under test in its most
favored direction.

4. Calculate the gain or loss of the antenna under test.

5. Post the results here and be prepared for an onslaught of criticism.

--
Bill, W6WRT
QSLs via LoTW

I suspect my caution about antenna gain stems from reading specs that
display extremely high "gain" numbers while the antennas are actually
quite
ordinary.

Absolutely. Whenever I see a gain number that dosen't reference something,
I assume they mean dBi, rather than dBd.

Dave VanHorn wrote:
Absolutely. Whenever I see a gain number that dosen't reference something,
I assume they mean dBi, rather than dBd.

Looks like some antenna retailers reference dBdl. :-)
(dl stands for dummy load)
--
73, Cecil, W5DXP



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"Cecil Moore" wrote in message
...
Dave VanHorn wrote:
Absolutely. Whenever I see a gain number that dosen't reference
something,
I assume they mean dBi, rather than dBd.

Looks like some antenna retailers reference dBdl. :-)
(dl stands for dummy load)

I've seen a few antennas that should be spec'd as negative dBdl. :)

On Sun, 11 Apr 2004 13:31:22 -0500, Cecil Moore
wrote:

Dave VanHorn wrote:
Absolutely. Whenever I see a gain number that dosen't reference something,
I assume they mean dBi, rather than dBd.

Looks like some antenna retailers reference dBdl. :-)
(dl stands for dummy load)

Actually it appears as if some manufacturers only measure the
directivity and express it in dB :-), completely ignoring the
efficiency, which is often quite low in "exotic" antenna designs.

An exotic antenna design with directivity 10 (10 dB) and 10 %
efficiency will have a 0 dB gain and will produce the same effective
radiation power (ERP) as an omnidirectional (directivity 1 or 0 dB)
antenna with 100 % efficiency when using the same transmitter power.

Paul OH3LWR