I'm sorry Jerry, but you don't know what you are talking about.

Smith Charts do not have anything to do with antenna efficiency or resonance.
The only thing that Smith Charts does is explain what is happening inside of a piece of coax X inches long. Note I do not use feet - since that is too vague.

On 1/23/2014 3:30 PM, Channel Jumper wrote:

Jerry Stuckle;814478 Wrote:
On 1/22/2014 5:32 PM, Irv Finkleman wrote:-
Q. Is there a relationship between the efficiency of an antenna and
the
received signal strength?
-

That depends on a lot of factors such as number of radials, length,
height above ground and ground conductivity, for start. Each situation

is different. But generally, for antennas such as 1/4 wave verticals,
radials will help.

Unfortunately, the only way to predict how an antenna is going to work
in a specific situation with any accuracy is with math and Smith Charts.

So you can use the "tried and true" method - put it up and see what
happens

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

I'm sorry Jerry, but you don't know what you are talking about.

Smith Charts do not have anything to do with antenna efficiency or
resonance.
The only thing that Smith Charts does is explain what is happening
inside of a piece of coax X inches long. Note I do not use feet -
since that is too vague.


Again, wrong. Smith Charts explain a LOT about antennas. But then I
can see you've never used one - but you have to try to correct someone
who knows more than you, anyway. But you only show your ignorance.

And BTW - I was using Smith Charts before you were born.

--
==================
Remove the "x" from my email address
Jerry, AI0K

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

On 1/24/2014 2:38 AM, Jeff wrote:

I'm sorry Jerry, but you don't know what you are talking about.

Smith Charts do not have anything to do with antenna efficiency or
resonance.
The only thing that Smith Charts does is explain what is happening
inside of a piece of coax X inches long. Note I do not use feet -
since that is too vague.

Whilst I agree with your first point, Smiths Charts do not "explain what
is happening inside of a piece of coax X inches long". They are an easy
way to plot impedances, and show what happens if you *change* the length
of coax, but more importantly they give you an easy way of working out
how to match impedances (with or without any length of coax involved).
They can also display other valuable quantities such as Q.

jeff


They do if you know how to use them properly. For instance, they will
tell you when the reactive portion of the impedance is zero (neither
capacitive nor inductive), which indicates resonance. They will also
tell you the antenna's impedance at a specific frequency. Both can be
used to indirectly determine antenna efficiency.

--
==================
Remove the "x" from my email address
Jerry Stuckle

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

On 1/25/2014 6:18 AM, Jeff wrote:

Whilst I agree with your first point, Smiths Charts do not "explain what
is happening inside of a piece of coax X inches long". They are an easy
way to plot impedances, and show what happens if you *change* the length
of coax, but more importantly they give you an easy way of working out
how to match impedances (with or without any length of coax involved).
They can also display other valuable quantities such as Q.

jeff


They do if you know how to use them properly. For instance, they will
tell you when the reactive portion of the impedance is zero (neither
capacitive nor inductive), which indicates resonance. They will also
tell you the antenna's impedance at a specific frequency. Both can be
used to indirectly determine antenna efficiency.


Rubbish, they tell you nothing more than the impedance at the point
that you wish to plot it. They tell you nothing about how well an
antenna may, or may, not radiate. A 50 ohm resistor will be purely
resistive (parasitic elements neglected) but won't radiate well. Also an
antenna does not have to resonant to radiate well or have high efficiency.

Jeff

Keep thinking that, Jeff, while those who know how to use Smith Charts
continue to design antennas.

Your ignorance is underwhelming.

--
==================
Remove the "x" from my email address
Jerry, AI0K

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

On 1/26/2014 5:09 AM, Jeff wrote:

Rubbish, they tell you nothing more than the impedance at the point
that you wish to plot it. They tell you nothing about how well an
antenna may, or may, not radiate. A 50 ohm resistor will be purely
resistive (parasitic elements neglected) but won't radiate well. Also an
antenna does not have to resonant to radiate well or have high
efficiency.

Jeff

Keep thinking that, Jeff, while those who know how to use Smith Charts
continue to design antennas.

Your ignorance is underwhelming.


Well Jerry, please help me increase my knowledge. Please tell me now to
show what "goes on *inside* a bit of coax" on a Smith chart, or how to
show the efficiency of an antenna from a Smith chart.

Jeff

I'll tell you what, troll. You go to college. Get a EE degree. Learn
the math and the theory. Them maybe you can understand basics and we
can discuss the subject intelligently (although I doubt it).

Usenet is not the place to try to teach you four years of math, physics
and electronics.

--
==================
Remove the "x" from my email address
Jerry Stuckle

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

Jeff wrote:

I'm sorry Jerry, but you don't know what you are talking about.

Smith Charts do not have anything to do with antenna efficiency or
resonance.
The only thing that Smith Charts does is explain what is happening
inside of a piece of coax X inches long. Note I do not use feet -
since that is too vague.

Whilst I agree with your first point, Smiths Charts do not "explain what
is happening inside of a piece of coax X inches long". They are an easy
way to plot impedances, and show what happens if you *change* the length
of coax, but more importantly they give you an easy way of working out
how to match impedances (with or without any length of coax involved).
They can also display other valuable quantities such as Q.

jeff

A Smith chart is a plot of reactance and resistance versus frequency and
can be used for just about anything, if you know how to use one.

In the case of an antenna, the chart shows what you have to match at any
particular frequency and the resonant frequency of the antenna, i.e. the
point where the reactance is zero.


--
Jim Pennino

"Jerry Stuckle" wrote in message
...
On 1/22/2014 5:32 PM, Irv Finkleman wrote:
Q. Is there a relationship between the efficiency of an antenna and the
received signal strength?


Definitely. Antenna efficiency works both ways - a less efficient antenna
will affect both transmit and received signals.

Just pondering on the matter. Because I have to operate with
restricted space antennas, usually with low efficiency, I wonder how
much of a relationship exists between Efficiency and Received Signal
Strength?


Just as much as between efficiency and transmitted signal strength.

This leads to more questions such as how much do radials contribute
to efficiency?


That depends on a lot of factors such as number of radials, length, height
above ground and ground conductivity, for start. Each situation is
different. But generally, for antennas such as 1/4 wave verticals,
radials will help.

IF that isn't enough, how much do radials contribute to the bandwidth?


See above.

And...

And...

I'm never to old to learn, but I am old enough that a lot of mathematical
mumbo jumbo and Smith Charts tend to confound me!

Unfortunately, the only way to predict how an antenna is going to work
in a specific situation with any accuracy is with math and Smith Charts.
So you can use the "tried and true" method - put it up and see what
happens


In this case the smith chart and antenna modling programs probably won't
work. In the small confins there are too many variables in the near field
of the antenna. Not that the program would not work, but it might take
years to measuer everything in the near field of the antenna.

Like you said , the tried and true method. Put something up and see how it
works.

Often people tend to overthink a simple problem or over think a problem
there is no easy solution for.

For now, it might be just as good and easy to tack a dipole up in the
cealing of the room even if it is bent at all kinds of angles.



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"Irv Finkleman" wrote in message
...
Q. Is there a relationship between the efficiency of an antenna and the
received signal strength?

Just pondering on the matter. Because I have to operate with
restricted space antennas, usually with low efficiency, I wonder how
much of a relationship exists between Efficiency and Received Signal
Strength?


Most of your problem is not going to be with the receiver. I am thinking
that Yaesu is around 5 watts or less. For the most part you can just throw
out any kind of antenna and hear lots more than you will be able to work
with 5 watts. You can probably stick 10 to 15 feet of wire in the back of
the rig and hear as much as you can with the MP-1 antenna in the same room.

First I would get rid of that rig and get one with 100 watts out. Not that
you can't work stations with 5 watts, but you will make many more cotacts
with around 100 watts on a miminal antenna.

For the antenna put up anything you can. You may need a good tuner to match
the antenna. You did not say if you are in an apartment on a high floor.
If so, stick up what ever you can vertical and load it with a coil if
needed, and drop a wire toward the ground for about 1/4 wavelength.

Forget about really trying to chart and graph any antenna for your
situation, Just throw up something and get on the air. I would almost
recommend one of the screwdriver type antennas and some wire for a ground
plane or lower part of a dipole for your situation. For 20 meters and up
you may give a dipole made out of 2 of the Hamstick type antennas a try.




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Thanks for all the replys guys.

Just to set the record straight, I have been a ham for
over fifty years, and a very active member of
the local ham club for over 30 (since I moved to Calgary).
I hold an advanced ticket and am not
totally ignorant on matters re antennas. I am a darned
good tech (most of my gear was bought broken and I
fixed it up), but sometimes I need simple answers
to a few questions -- and this is the place for that!

BUT! -- for the past four years I have been in and
out of the hospital and off and on some pretty mind bending
medications -- consequently sometimes I cannot think as straight
as when I was younger, nor do I move around well. I'm not
yet demented but do admit to being crazy but not dangerous!

I am somewhat handicapped, and live in a senior's
residence. I cannot have an outside antenna other
than what I can fit on a small (6'x9' balcony. I can have a whip
sticking over the side, but I still need to remain relatively invisible
(all I tell the other residents is that it is for
listening to shortwave lest I be blamed for non-functioning
TV remote controls, cordless phones with low batteries, and the like).

I plan to build a magnetic loop this summer, but winter hangs around
here until about the end of May! In the meantime I am trying to figure
what I can do to operate from within the confines of my studio
suite -- once the loop is built I can put it on the balcony and tune it
remotely from inside. I intend to operate QRP using an FT-817ND.
Once I find I can operate undetected, I also have an FT-857 and may
go to a few more watts.

Insofar as radials are concerned, they will be laid around the base
of the antenna, mainly for the purpose of getting the best match
possible for the MP-1 vertical antenna, or any other things I may
try in the future. I've had a number of suggestions to use hamsticks
in a dipole configuration (won't fit on the balcony and makes
band changing difficult), baluns (not required with the whip or a
magnetic loop), higher power to overcome antenna inefficiency, and
how easy it is to learn to use a Smith Chart, and even move. I'm
where I plan to stay (I get great medical care here, and the
nurses are cute -- when I leave, they'll have to carry me out. So,
as I've said before, it's a case of 'RADIATE OR DIE TRYING!'.

Suggestions that I go to higher power, buy a screwdriver antenna, and
hints about baluns, don't help -- I've got to make do with what I
have on hand, and I will do it. My main question asking whether there
is a relationship between antenna efficiency and received signal
strength (will a more efficient antenna result in a higher S-meter
indication?) is all I really wanted to ask. The radial matter was
simply a possible way to increase the efficiency (by reducing ground
losses). Power-wise is not a problem for me -- it's not a matter of
contact quantity but quality. It's sort of like fly-fishing versus
the dynamite fishing lure. If I get one good QSO a day, I'll be
happy.

I have trouble moving around physically so that's why I'm so slow
in collecting the materials I need, and getting something going, but I
want to do it slowly, but surely. I have a couple of ham chums
who will help me as needed.

I just got enough wire to make some radials for 20M, so I'll cut and
throw them around the base of the MP-1 and see what I can do.
Eventually I'd like to work 80 thru 10M but that's for later.

Thanks for your replies and suggestions, many of which have been
helpful, but bear with me -- I'm getting there slowly, and with
a little luck the end is in sight! It's just that I can't do anything
very quickly, but with time I'll do it all!

73

Irv VE6BP

"Irv Finkleman" wrote in message news

Thanks for all the replys guys.

Just to set the record straight, I have been a ham for
over fifty years, and a very active member of
the local ham club for over 30 (since I moved to Calgary).
I hold an advanced ticket and am not
totally ignorant on matters re antennas. I am a darned
good tech (most of my gear was bought broken and I
fixed it up), but sometimes I need simple answers
to a few questions -- and this is the place for that!

Irv--
I have had "reasonable" results using a horizontal loop strung around the
top of the shack walls.

I used buttons for insulators, and thread to fasten the buttons to the wall
via thumbtacks. The wire was 28 ga if I recall.

My first attempt was with a 15 meter loop. I had a little extra space, so I
just made the loop a little larger and used a tuner to calm things down.

This is not the ultimate antenna, but isn't too bad considering that it is
indoors.

Good luck with your living arrangement and ham activities.

Wayne
W5GIE
Redlands, CA