My present antenna, which is for 160m and above, is about the size of
two shoe
boxes and is less than 2:1 swr (50 ohm) across the band when
situatedat the
top of my tower.
I have googled a lot over the last month or so to determine if there
has been
claims for the 'smallest' transmitting antenna and what the criteria
consisted of.
If I knew what it was I would concentrate on making my antenna smaller
to reflect
something more close to point radiation which has been theorized as
being possible.
Seems like that there is no real definition of what a 'small' compact
antenna
actually comprises of together with power handling capabilities!
True, for receiving only there are many contestants all with
different criteria,
but for the ham community there is absolutely nothing for anybody to
compare
with other than such claims as 'mine is the smallest and I work
anything I can
hear' !. Can anybody point to a transmitting antenna that can be
considered
'small ' without the need for a ground plane, which thus puts it
into the
'antenna systems' class ?
For a point of interest, I am presently using a reflector made from a
garbage can lid,
but it is not acting in anyway a dish antenna works when the reflector
is grounded!
As an aside, most posters to the group are aware that a modest sum was
offered
who could disprove my claim but with no takers. So can we put that
particular subject
aside and concentrate only on the request of this posting which
should cut off
most of the insults ?
Best regards to all
Art Unwin

art wrote:
My present antenna, which is for 160m and above, is about the size of
two shoe
boxes and is less than 2:1 swr (50 ohm) across the band when
situatedat the
top of my tower.
I have googled a lot over the last month or so to determine if there
has been
claims for the 'smallest' transmitting antenna and what the criteria
consisted of.
If I knew what it was I would concentrate on making my antenna smaller
to reflect
something more close to point radiation which has been theorized as
being possible.
Seems like that there is no real definition of what a 'small' compact
antenna
actually comprises of together with power handling capabilities!
True, for receiving only there are many contestants all with
different criteria,
but for the ham community there is absolutely nothing for anybody to
compare
with other than such claims as 'mine is the smallest and I work
anything I can
hear' !. Can anybody point to a transmitting antenna that can be
considered
'small ' without the need for a ground plane, which thus puts it
into the
'antenna systems' class ?
For a point of interest, I am presently using a reflector made from a
garbage can lid,
but it is not acting in anyway a dish antenna works when the reflector
is grounded!
As an aside, most posters to the group are aware that a modest sum was
offered
who could disprove my claim but with no takers. So can we put that
particular subject
aside and concentrate only on the request of this posting which
should cut off
most of the insults ?
Best regards to all
Art Unwin


Hi Art,
Get a copy of Balanis' _Antenna Theory, Analysis and Design_,
second edition, and read section 11.5, Fundamental Limits of
Electrically Small Antennas. Also, in the _Antenna Engineering
Handbook_, third edition, read section 6, Small Antennas by Harold A.
Wheeler. I won't vouch for any of the information, but it should give
you some ideas on what the practical limits of small antennas are
supposed to be by reputable people who have thought the subject
through.
73,
Tom Donaly, KA6RUH

On 13 Feb, 20:34, "Tom Donaly" wrote:
art wrote:
My present antenna, which is for 160m and above, is about the size of
two shoe
boxes and is less than 2:1 swr (50 ohm) across the band when
situatedat the
*top of my tower.
I have googled a lot over the last month or so to determine if there
has been
claims for the 'smallest' transmitting antenna and what the criteria
consisted of.
If I knew what it was I would concentrate on making my antenna smaller
to reflect
something more close to point radiation which has been theorized as
being possible.
Seems like that there is no real definition of what a 'small' compact
antenna
actually comprises of *together with power handling capabilities!
*True, for receiving only there are many contestants all with
different criteria,
but for the ham community there is absolutely nothing for anybody to
compare
*with other than such claims as 'mine is the smallest and I work
anything I can
*hear' !. Can anybody point to a transmitting antenna that can be
considered
*'small ' *without the need for a ground plane, which thus puts *it
into the
*'antenna systems' *class ?
For a point of interest, I am presently using a reflector made from a
garbage can lid,
but it is not acting in anyway a dish antenna works when the reflector
is grounded!
As an aside, most posters to the group are aware that a modest sum was
offered
who could disprove my claim but with no takers. So can we put that
particular subject
*aside and concentrate only on the request of this posting which
should cut off
most of the insults ?
Best regards to all
Art Unwin

Hi Art,
* * * * *Get a copy of Balanis' _Antenna Theory, Analysis and Design_,
second edition, and read section 11.5, Fundamental Limits of
Electrically Small Antennas. Also, in the _Antenna Engineering
Handbook_, third edition, read section 6, Small Antennas by Harold A.
Wheeler. I won't vouch for any of the information, but it should give
you some ideas on what the practical limits of small antennas are
supposed to be by reputable people who have thought the subject
through.
73,
Tom Donaly, KA6RUH- Hide quoted text -

- Show quoted text -

Understood Tom. Wheeler looks at the subject from many angles but
does
not get into overall specifics. For instance, the smallest volume
antenna can be based on wire size which in turn is based on power
output.
This effectively states that the smallest radiater is the size of a
pinhead!
Practicality states that the wire diameter is exceedingly small
diameter
plus extremely low power, all of which is based on a arrangement that
is
resonant. In practical terms I would point to a Fractal antenna
however, the
criteria for 'smallness' or 'compact' must factor in efficiency with
respect
to wave length where the latter antenna would fail. Same goes for the
EH
antenna which only can be regarded as a 'system'. Or for that matter
a
resister which as a load is just a heat exchanger.
In the amateur field one should incorporate max power allowed on key
down for a certain period of time without loading of any sort and
where
radiation is rated with respect to a unit volume. With that in mind I
have found nothing to aim for to qualify as a 'small' or 'compact'
antenna.
Looking at the trade magazine 'Antenna' there is always demands for a
"smaller"
design antenna as something that is holding up electronic progress,
but at
the same time zero reference as to what defines 'small' since design
is
covered by Maxwell and not by Congress
Best regards
Art Unwin.

Art,
I am convinced that you are experimenting in an area of antenna
practices that has been neglected... I am always interested in
advances on the art and practice of antennas... You hereby offered the
opportunity to drop by my qth with your reduced size 160 antenna... If
transportation is a problem I will fly my airplane to your area and
bring you back to Michigan, or arrange other transportation for you at
my expense...
I will personally mount your antenna at the top of a 150 foot tower
and we can measure the near field intensity and far field signal
strength developed by the antenna, compared to my normal size antennas
which are off another tower at a distance .. I am sure I can convince
a few of the regulars on here to be on the band and be ready to
participate with signal strength measurements, spectrum analyzers,
etc... This would form an excellent basis for an article for you to
publish - complete with reports from third parties - on a major
advance in the theory and practice of antennas...

If I am not convenient to you then I suspect that W8JI or others would
offer a similar testing range and I still would be happy to provide
transportation just to be a part of an exciting new chapter in radio
experimentation...


cordially,
denny - k8do

On 14 Feb, 04:28, Denny wrote:
Art,
I am convinced that you are experimenting in an area of antenna
practices that has been neglected... I am always interested in
advances on the art and practice of antennas... You hereby offered the
opportunity to drop by my qth with your reduced size 160 antenna... If
transportation is a problem I will fly my airplane to your area and
bring you back to Michigan, or arrange other transportation for you at
my expense...
I will personally mount your antenna at the top of a 150 foot tower
and we can measure the near field intensity and far field signal
strength developed by the antenna, compared to my normal size antennas
which are off another tower at a distance .. *I am sure I can convince
a few of the regulars on here to be on the band and be ready to
participate with signal strength measurements, spectrum analyzers,
etc... *This would form an excellent basis for an article for you to
publish - complete with reports from third parties - on a major
advance in the theory and practice of antennas...

If I am not convenient to you then I suspect that W8JI or others would
offer a similar testing range and I still would be happy to provide
transportation just to be a part of an exciting new chapter in radio
experimentation...

cordially,
denny - k8do

That is very kind of you but there is no need for any all out effort
regarding travel. What I will do is look around for some copper scraps
and make one for you and use the normal mail. Since I will probably
be
using scrap that I can find my guess is that it would behove you to
use
500 watts or less for your playing around.
I will send it off about 14 days or less from now and hopefully the
weather will be warmer for you.If I don't find any scraps then I will
send the one on the tower even tho it is not of the optimum design use
can use it as is on different bands. At the moment I am making one
that
can fit into a trouser pocket so that may be the one you get.
Best regards
Art Unwin

Denny wrote:
Art,
I am convinced that you are experimenting in an area of antenna
practices that has been neglected... I am always interested in
advances on the art and practice of antennas... You hereby offered the
opportunity to drop by my qth with your reduced size 160 antenna... If
transportation is a problem I will fly my airplane to your area and
bring you back to Michigan, or arrange other transportation for you at
my expense...
I will personally mount your antenna at the top of a 150 foot tower
and we can measure the near field intensity and far field signal
strength developed by the antenna, compared to my normal size antennas
which are off another tower at a distance .. I am sure I can convince
a few of the regulars on here to be on the band and be ready to
participate with signal strength measurements, spectrum analyzers,
etc... This would form an excellent basis for an article for you to
publish - complete with reports from third parties - on a major
advance in the theory and practice of antennas...

If I am not convenient to you then I suspect that W8JI or others would
offer a similar testing range and I still would be happy to provide
transportation just to be a part of an exciting new chapter in radio
experimentation...


cordially,
denny - k8do

I suggest that you take pains to make sure the feedline is well
decoupled - a couple of current baluns, one at the feedpoint and one a
quarter wave down the line, should be adequate. An extra measure would
be to measure the common mode feedline current to make sure it's
minimal. That would go a long way toward silencing critics (like me) who
believe that reported good results from such small antennas are often
the result of feedline radiation -- that is, that the feedline is the
primary radiator and the "antenna" plays only a minor role.

Roy Lewallen, W7EL

On 14 Feb, 12:08, Roy Lewallen wrote:
Denny wrote:
Art,
I am convinced that you are experimenting in an area of antenna
practices that has been neglected... I am always interested in
advances on the art and practice of antennas... You hereby offered the
opportunity to drop by my qth with your reduced size 160 antenna... If
transportation is a problem I will fly my airplane to your area and
bring you back to Michigan, or arrange other transportation for you at
my expense...
I will personally mount your antenna at the top of a 150 foot tower
and we can measure the near field intensity and far field signal
strength developed by the antenna, compared to my normal size antennas
which are off another tower at a distance .. *I am sure I can convince
a few of the regulars on here to be on the band and be ready to
participate with signal strength measurements, spectrum analyzers,
etc... *This would form an excellent basis for an article for you to
publish - complete with reports from third parties - on a major
advance in the theory and practice of antennas...

If I am not convenient to you then I suspect that W8JI or others would
offer a similar testing range and I still would be happy to provide
transportation just to be a part of an exciting new chapter in radio
experimentation...

cordially,
denny - k8do

I suggest that you take pains to make sure the feedline is well
decoupled - a couple of current baluns, one at the feedpoint and one a
quarter wave down the line, should be adequate. An extra measure would
be to measure the common mode feedline current to make sure it's
minimal. That would go a long way toward silencing critics (like me) who
believe that reported good results from such small antennas are often
the result of feedline radiation -- that is, that the feedline is the
primary radiator and the "antenna" plays only a minor role.

Roy Lewallen, W7EL- Hide quoted text -

- Show quoted text -

I understand all that. If Tom wishes to add one for his
own satisfaction that's fine by me.
If he wants to test it then I am confident he will do what
ever is necessary without comment from me.
I have no wish to influence him in any way. He cam make his own call
even if it means that it burns up. I have no experience with 180 M
and have only loaded it for 100W. As I have stated before, I have not
been active for years because of illnesses etc and I would not
presume
that Tom would need any assistance from a blithering idiot and
liar such as I.
W8TI Tom laughed his socks off when I mentioned resonant tank
circuits
in equilibrium and refused to give me any time for discussion.
On the other hand, Tom in Michigan has always been polite to me
and appears to have a genuine interest in new ideas, so I have
worked all day today in getting things together so I can get
one to him as quickly as possible.

Art wrote:
"My present antenna, which is for 160 m and above, is about the size of
two shoe boxes and is less than 2:1 swr (50 ohm) across the band when
situated at the tip of my tower."

Outstanding! An effective antenna needs to be an appreciable portion of
wavelength in some dimension.

If Art`s antenna is an appreciable portion of 525 feet it can radiate
well on 160 meters.

Any length of wire carrying an RF current is capable of radiation.
Significant radiation from a short wire requires much current.

With a garbage can lid for a reflector, a helical antenna can be made.
Were it 3 feet across in diameter (0.9 meter) the helix might work on 3
meters as the diameter needs to be about 0,3 lambda. Terman gives
helical antenna information on page 909 of his 1955 opus. His best bets
for small antenas are the corner reflector and the Yagi.

Best regards, Richard Harrison, KB5WZI

Shucks, I have an antenna that's no bigger than a baseball, and it gives
better than a 1.5:1 SWR over more than the whole HF band when I connect
it directly to my transmitter. If I hang it up real high, the SWR gets
better yet.

Roy Lewallen, W7EL

Richard Harrison wrote:
Art wrote:
"My present antenna, which is for 160 m and above, is about the size of
two shoe boxes and is less than 2:1 swr (50 ohm) across the band when
situated at the tip of my tower."

Outstanding! An effective antenna needs to be an appreciable portion of
wavelength in some dimension.

If Art`s antenna is an appreciable portion of 525 feet it can radiate
well on 160 meters.

Any length of wire carrying an RF current is capable of radiation.
Significant radiation from a short wire requires much current.

With a garbage can lid for a reflector, a helical antenna can be made.
Were it 3 feet across in diameter (0.9 meter) the helix might work on 3
meters as the diameter needs to be about 0,3 lambda. Terman gives
helical antenna information on page 909 of his 1955 opus. His best bets
for small antenas are the corner reflector and the Yagi.

Best regards, Richard Harrison, KB5WZI

On 15 Feb, 15:29, (Richard Harrison) wrote:
Art wrote:

"My present antenna, which is for 160 m and above, is about the size of
two shoe boxes and is less than 2:1 swr (50 ohm) across the band when
situated at the tip of my tower."

Outstanding! An effective antenna needs to be an appreciable portion of
wavelength in some dimension.

If Art`s antenna is an appreciable portion of 525 feet it can radiate
well on 160 meters.

Any length of wire carrying an RF current is capable of radiation.
*******
Yes, but it is not useable if C and L for the length involved and
frequency of use is not adhered to.
Implicit in Maxwell's laws is that a radiator can be any size or shape
as long as it is in equilibrium. Without the inclusion of that last
word
all laws of the masters are invalid.

Significant radiation from a short wire requires much current.

With a garbage can lid for a reflector, a helical antenna can be made.
Were it 3 feet across in diameter (0.9 meter) the helix might work on 3
meters as the diameter needs to be about 0,3 lambda. Terman gives
helical antenna information on page 909 of his 1955 opus. His best bets
for small antenas are the corner reflector and the Yagi.
######


It is not the physical size that is important whith respect to a dish
it is the wavelength between the two objects that counts. A simple
helix
antenna can use a reflector in place of a ground plane not as an
optical
ray deflector.Such an array is not in a state of equilibrium



Best regards, Richard Harrison, KB5WZI