Antenna physical size
 

Art Unwin wrote:

Considering that it meets Maxwells requirements and is at least a
wavelenght
of a radiator my expectations are much higher than yours
I suspect that the output will exceed that of a 160 M antenna which
has a ground plane.
I also suspect that if I diddn't concentrated so much on small
physical size it could easily be uprated
to compete with a yagi!

I can hardly wait for the trials, Art.

Either way the
experimental trail undertaken I have found to
be very rewarding as many other amateurs have had when experimenting
with antennas and who refuse
to accept that all is known

Perhaps you're repeating the attempts of those experimenters of long
ago, who knew and discarded.

Dave K8MN

Antenna physical size
 

Art Unwin wrote:

OK mike one last time.
Make a former to wind apon.
Set it up vertically and secure so that it doesn't fall over.
Get two reels of insulated wire preferbly pre wound paired
wire on each reel. Join the paired wires
Put the joint at the rear of the former with one reel to the left
and one reel to the right.
Wnd one wire clockwise and then wind counterclockwise the
wire from the other reel. Repeat these two functions making
sure the overlapped wires stay parallel with each other.
When you have completed the length of the spool then join
one wire to another wire from the opposite reel. You now have two
wires in your hands
one from each of the reels. These two wires are what you connect to
the transmission line..
Suggestions for the former. Make two cross arrangements using 1/2 inch
plastic piping.
At each of the 8 ends place a tee connection. Four pipes around a foot
long can the join the two sections,
Use tees instead of elbows so the antenna is easier to mount.
If you want it to be all frequencie:
Cut a 1/2 inch plastic pipe in half,' length wise.
Make wire loops and fit them over the cut pipe and solder them tight.
Place a quick start threaded rod inside the cut pipe with a motor at
one end.
Make a electrical wiper to place on the quick start thread to make
electrical
connection to the loops as the motor turns.
Connect a meter to one of the start wires and disconnect it from the
joint.
Place a sowing needle on the other end of the instrument and pierce
the
wires in sequence until one
gets to the coax connection points marking each wire that is
connected to the meter.
Connect the marked wires to the loop that were made sp electrical
contact
can be made to the threaded shaft
Connect the shaft to one of the wires that consists of the feed
points.
Rejoin the wire connections at the start point so that now you have a
complete electrical
circuit starting at the feed points
Place assembly anywhere and apply power and have a qso.
Now will somebody that is savvy with computors do that excercise that
I suggested
with regard to tipped radiators and report on it before you make this
antenna or start
tilting towers around ten degrees sinc the change is not worth it when
calculating total gain?

Well, there it is. I'm going to scrounge a "former" and a "sowing"
needle and get right to work.

Dave K8MN

Antenna physical size
 

Dave Heil wrote:
Art Unwin wrote:

OK mike one last time.
Make a former to wind apon.
Set it up vertically and secure so that it doesn't fall over.
Get two reels of insulated wire preferbly pre wound paired
wire on each reel. Join the paired wires
Put the joint at the rear of the former with one reel to the left
and one reel to the right.
Wnd one wire clockwise and then wind counterclockwise the
wire from the other reel. Repeat these two functions making
sure the overlapped wires stay parallel with each other.
When you have completed the length of the spool then join
one wire to another wire from the opposite reel. You now have two
wires in your hands
one from each of the reels. These two wires are what you connect to
the transmission line..
Suggestions for the former. Make two cross arrangements using 1/2 inch
plastic piping.
At each of the 8 ends place a tee connection. Four pipes around a foot
long can the join the two sections,
Use tees instead of elbows so the antenna is easier to mount.
If you want it to be all frequencie:
Cut a 1/2 inch plastic pipe in half,' length wise.
Make wire loops and fit them over the cut pipe and solder them tight.
Place a quick start threaded rod inside the cut pipe with a motor at
one end.
Make a electrical wiper to place on the quick start thread to make
electrical
connection to the loops as the motor turns.
Connect a meter to one of the start wires and disconnect it from the
joint.
Place a sowing needle on the other end of the instrument and pierce
the
wires in sequence until one
gets to the coax connection points marking each wire that is
connected to the meter.
Connect the marked wires to the loop that were made sp electrical
contact
can be made to the threaded shaft
Connect the shaft to one of the wires that consists of the feed
points.
Rejoin the wire connections at the start point so that now you have a
complete electrical
circuit starting at the feed points
Place assembly anywhere and apply power and have a qso.
Now will somebody that is savvy with computors do that excercise that
I suggested
with regard to tipped radiators and report on it before you make this
antenna or start
tilting towers around ten degrees sinc the change is not worth it when
calculating total gain?

Well, there it is. I'm going to scrounge a "former" and a "sowing"
needle and get right to work.

Dave K8MN


Don't forget an 'apon'....

Dave WD9BDZ

Antenna physical size
 

David G. Nagel wrote:
Dave Heil wrote:

Well, there it is. I'm going to scrounge a "former" and a "sowing"
needle and get right to work.

Dave K8MN


Don't forget an 'apon'....


Can you guys tell us the correct way to spell coil former? It's a
bobbin made of insulating material upon which wire is wound. Here's one
that got a patent:

http://www.patentstorm.us/patents/6262650.html


- 73 de Mike N3LI -

Antenna physical size
 

Michael Coslo wrote:
David G. Nagel wrote:
Dave Heil wrote:

Well, there it is. I'm going to scrounge a "former" and a "sowing"
needle and get right to work.

Dave K8MN


Don't forget an 'apon'....


Can you guys tell us the correct way to spell coil former? It's a
bobbin made of insulating material upon which wire is wound. Here's one
that got a patent:

http://www.patentstorm.us/patents/6262650.html

You've done well, Mike. Now what is a "sowing needle" and what might an
"apon" be?

Dave K8MN
the product of an inferior American education
(at least according to Art Unwin)

Antenna physical size
 

Michael Coslo wrote:
David G. Nagel wrote:
Dave Heil wrote:

Well, there it is. I'm going to scrounge a "former" and a "sowing"
needle and get right to work.

Dave K8MN
Don't forget an 'apon'....


Can you guys tell us the correct way to spell coil former? It's
a bobbin made of insulating material upon which wire is wound.

Alternatively, wind the wire onto a mandrill.


--

73 from Ian GM3SEK 'In Practice' columnist for RadCom (RSGB)
http://www.ifwtech.co.uk/g3sek

Antenna physical size
 

Mike Coslo wrote:
On Fri, 14 Mar 2008 11:57:41 -0700, Roy Lewallen wrote:

Richard Harrison wrote:
Build a small scale model that can be tested indoors and report its
characteristics. Antennas are scaleable.
That's more easily said than done. One of the critical characteristics
of a small antenna is loss. And to correctly replicate loss in a scaled
antenna requires scaling the conductivity of the conductors as the
square root of the frequency. To scale to a higher frequency requires
that the conductivity be better than the original. Unless the original
is made from lead and the scale factor moderate, this wouldn't be
possible.

If what I suspect is true, would not the coax also need to be scaled?

Dunno. What do you suspect?

Roy Lewallen, W7EL

Antenna physical size
 

Ian White GM3SEK wrote in
:

Alternatively, wind the wire onto a mandrill.

Or would that be a mandrel?

Owen

Antenna physical size
 

Michael Coslo wrote:

Can you guys tell us the correct way to spell coil former? It's a
bobbin made of insulating material upon which wire is wound. Here's one
that got a patent:

http://www.patentstorm.us/patents/6262650.html


"Former" is simply the British English equivalent to "coil form" in U.S.
English.

Roy Lewallen, W7EL

Antenna physical size
 

Owen Duffy wrote:
Ian White GM3SEK wrote in
:

Alternatively, wind the wire onto a mandrill.

Or would that be a mandrel?


I've seen both spellings recommended in print, but winding wire onto a
mandrill will be far more entertaining.


--

73 from Ian GM3SEK 'In Practice' columnist for RadCom (RSGB)
http://www.ifwtech.co.uk/g3sek

Antenna physical size
 

Ian White GM3SEK wrote in news:U5VH68Pl733HFA
:

Owen Duffy wrote:
Ian White GM3SEK wrote in
:

Alternatively, wind the wire onto a mandrill.

Or would that be a mandrel?


I've seen both spellings recommended in print, but winding wire onto a
mandrill will be far more entertaining.

Ah, when popularity displaces correctness!

But, I can see the confusion when you place a mandrel into a drill to
wind the coil.

Or should it be a persondrel? Is PC still in vogue?

Owen

PS: my (rather old) Concise Oxford Dictionary thinks a mandrill is a
"Large fierce West African baboon", fierce I guess when bound with wire.
It hasn't caught up with the alternative use for mandrel, well not by
1979.

Antenna physical size
 

"Roy Lewallen" wrote in message
...
Richard Harrison wrote:

Build a small scale model that can be tested indoors and report its
characteristics. Antennas are scaleable.

That's more easily said than done. One of the critical characteristics of
a small antenna is loss. And to correctly replicate loss in a scaled
antenna requires scaling the conductivity of the conductors as the square
root of the frequency. To scale to a higher frequency requires that the
conductivity be better than the original. Unless the original is made from
lead and the scale factor moderate, this wouldn't be possible.

Roy Lewallen, W7EL

Hi Roy

I'm curious to know why you didnt use stainless steel as an example rather
than lead as your example.

Jerry

Antenna physical size
 

I can bear it no longer. We have Art the English educated antenna expert
who cannot write the English language,and now a Scot who doesn't know that a
Mandrill is a West African Baboon.
If you wind Art's wire on a Baboon it is going to get seriously ****ed off.
From an elderly Pom in Aus.
"Ian White GM3SEK" wrote in message
...
Michael Coslo wrote:
David G. Nagel wrote:
Dave Heil wrote:

Well, there it is. I'm going to scrounge a "former" and a "sowing"
needle and get right to work.

Dave K8MN
Don't forget an 'apon'....


Can you guys tell us the correct way to spell coil former? It's a
bobbin made of insulating material upon which wire is wound.

Alternatively, wind the wire onto a mandrill.


--

73 from Ian GM3SEK 'In Practice' columnist for RadCom (RSGB)
http://www.ifwtech.co.uk/g3sek

Antenna physical size
 

I can`t find it now, but I believe Mark, NM5K on this thread wrote that
my quotation from page 929 of Terman`s 1955 opus raised flags. I said I
was surprised in my original posting. I was aware at the time that Kraus
shows identical field paterns for a small loop an a short dipole, but
the E and H fields are exchaged between the two antenna types. The Kraus
diagrams are on page 58 of the 3rd edition of "Antennas".

I`ve learned not to quarrel with Terman. So, I reread the page 929
quotation. I posted it correctly. He did say a loop antenna responds
much less to the electric induction field than does a simple wire
antenna of comparable intercept area.

So I looked for a similar statement in Terman`s "Radio Engineering" in
an edition published in 1947. On page 664, I find:
"In the case of a doublet antenna, the electrostatic induction field
becomes proportionally stronger than the magnetic induction field as one
comes closer to the antenna. With the loop antenna the reverse is true."

We know that the induction, or near, field is equal to the radiation
field at about 1/6 wavelength. Closer to the radiator, the induction
field is much stronger. Farther away, the radiation field predominates
Our intrest is usually in the radiation, or far field. Measurements are
usually made several wavelengths away from an antenna to be sure the
induction field has become insignificant.

I`ve thought how and why my experience confirms Terman`s statements
but I won`t bore anyone with these thoughts.

Best regards, Richard Harrison, KB5WZI

Antenna physical size
 

Roy Lewallen wrote:
Mike Coslo wrote:
On Fri, 14 Mar 2008 11:57:41 -0700, Roy Lewallen wrote:

Richard Harrison wrote:
Build a small scale model that can be tested indoors and report its
characteristics. Antennas are scaleable.
That's more easily said than done. One of the critical characteristics
of a small antenna is loss. And to correctly replicate loss in a scaled
antenna requires scaling the conductivity of the conductors as the
square root of the frequency. To scale to a higher frequency requires
that the conductivity be better than the original. Unless the original
is made from lead and the scale factor moderate, this wouldn't be
possible.

If what I suspect is true, would not the coax also need to be scaled?

Dunno. What do you suspect?

I suspect that the antenna is a tuned circuit on top of coax, and it
needs that coax to radiate effectively. So just scaling the antenna
wouldn't translate to the same results?

- 73 de Mike N3LI -

Antenna physical size
 

Dave Heil wrote:
Michael Coslo wrote:
David G. Nagel wrote:
Dave Heil wrote:

Well, there it is. I'm going to scrounge a "former" and a "sowing"
needle and get right to work.

Dave K8MN


Don't forget an 'apon'....


Can you guys tell us the correct way to spell coil former? It's a
bobbin made of insulating material upon which wire is wound. Here's
one that got a patent:

http://www.patentstorm.us/patents/6262650.html

You've done well, Mike. Now what is a "sowing needle" and what might an
"apon" be?

Those are typos. I just figure we should only rib Art on the real
typos. 8^)


Dave K8MN
the product of an inferior American education
(at least according to Art Unwin)

Me too 8^)

- 73 d eMike N3LI -

Antenna physical size
 

Jerry wrote:
"Roy Lewallen" wrote in message
...
Richard Harrison wrote:
Build a small scale model that can be tested indoors and report its
characteristics. Antennas are scaleable.
That's more easily said than done. One of the critical characteristics of
a small antenna is loss. And to correctly replicate loss in a scaled
antenna requires scaling the conductivity of the conductors as the square
root of the frequency. To scale to a higher frequency requires that the
conductivity be better than the original. Unless the original is made from
lead and the scale factor moderate, this wouldn't be possible.

Roy Lewallen, W7EL

Hi Roy

I'm curious to know why you didnt use stainless steel as an example rather
than lead as your example.

The main reason is that many years ago I was involved in using physical
models scaled up in size in order to optimize microstrip transitions and
other features used for time domain equipment having rise times on the
order of 10 ps. At that time, I looked to see if it was possible to
model the loss accurately, and found I'd need a semiconductor to do it.
I recall that lead was about the least conductive common metal
available. So I tossed that one out in my example.

I don't remember investigating stainless or other steels, but that might
indeed be a way to do it. To make a strictly accurate scale model, the
permeability and permittivity (dielectric constant) stay fixed with
frequency, so a non-magnetic stainless steel would be necessary.
However, since the skin depth is inversely proportional to the square
root of permeability, a magnetic material has the loss of a non-magnetic
material having a conductivity lower by a factor equal to its relative
permeability. So a magnetic material such as steel or magnetic stainless
steel might be used to extend the range of possible loss values
available for making larger physical models. There's a very large number
of steel and stainless steel alloys, and good information on the
required parameters can be hard or impossible to find. So samples would
probably have to be measured.

In the case in question, however, a smaller scale model was proposed,
and we can probably assume that the original is made from copper. So
it's not really possible to create a smaller scale model which
accurately imitates the loss of the original.

Roy Lewallen, W7EL

Antenna physical size
 

Michael Coslo wrote:
Roy Lewallen wrote:
Mike Coslo wrote:
On Fri, 14 Mar 2008 11:57:41 -0700, Roy Lewallen wrote:

Richard Harrison wrote:
Build a small scale model that can be tested indoors and report its
characteristics. Antennas are scaleable.
That's more easily said than done. One of the critical characteristics
of a small antenna is loss. And to correctly replicate loss in a scaled
antenna requires scaling the conductivity of the conductors as the
square root of the frequency. To scale to a higher frequency requires
that the conductivity be better than the original. Unless the original
is made from lead and the scale factor moderate, this wouldn't be
possible.

If what I suspect is true, would not the coax also need to be scaled?

Dunno. What do you suspect?

I suspect that the antenna is a tuned circuit on top of coax, and it
needs that coax to radiate effectively. So just scaling the antenna
wouldn't translate to the same results?

Yes. If the coax is radiating, it's part of the antenna. To make an
accurate scale model of the antenna, you have to scale the entire
antenna (that is, every radiating conductor), not just some part of it
which someone has declared to be "The Antenna". In this case, however,
radiating coax isn't likely to be a major fraction of the total loss, so
scaling it in a model probably wouldn't make much difference to the
loss. Its diameter might have a noticeable effect on how much current it
gets and therefore how much it radiates, though, which is an argument in
favor of scaling it.

Roy Lewallen, W7EL

Antenna physical size
 

On Mar 18, 12:26 pm, Michael Coslo wrote:
Roy Lewallen wrote:
Mike Coslo wrote:
On Fri, 14 Mar 2008 11:57:41 -0700, Roy Lewallen wrote:

Richard Harrison wrote:
Build a small scale model that can be tested indoors and report its
characteristics. Antennas are scaleable.
That's more easily said than done. One of the critical characteristics
of a small antenna is loss. And to correctly replicate loss in a scaled
antenna requires scaling the conductivity of the conductors as the
square root of the frequency. To scale to a higher frequency requires
that the conductivity be better than the original. Unless the original
is made from lead and the scale factor moderate, this wouldn't be
possible.

If what I suspect is true, would not the coax also need to be scaled?

Dunno. What do you suspect?

I suspect that the antenna is a tuned circuit on top of coax, and it
needs that coax to radiate effectively. So just scaling the antenna
wouldn't translate to the same results?

- 73 de Mike N3LI -

If you are familiar with computor programming then why not model it
instead of repeating over and over again this transmission line
radiation theory.?

Antenna physical size
 

Ian White GM3SEK wrote:


Alternatively, wind the wire onto a mandrill.


Howl! Almost lost my coffee on that one....

- 73 de Mike N3LI -

Antenna physical size
 

On Tue, 18 Mar 2008 09:11:57 GMT, Owen Duffy wrote:

Alternatively, wind the wire onto a mandrill.

Or would that be a mandrel?


I've seen both spellings recommended in print, but winding wire onto a
mandrill will be far more entertaining.

PS: my (rather old) Concise Oxford Dictionary thinks a mandrill is a
"Large fierce West African baboon", fierce I guess when bound with wire.
It hasn't caught up with the alternative use for mandrel, well not by
1979.

The OED being old only excludes newer words - either way, mine shows
the spelling mandril.

73's
Richard Clark, KB7QHC

Antenna physical size
 

Ian White GM3SEK wrote:
Michael Coslo wrote:

David G. Nagel wrote:

Dave Heil wrote:


Well, there it is. I'm going to scrounge a "former" and a "sowing"
needle and get right to work.

Dave K8MN

Don't forget an 'apon'....



Can you guys tell us the correct way to spell coil former? It's
a bobbin made of insulating material upon which wire is wound.


Alternatively, wind the wire onto a mandrill.


Do you sedate the mandrill first? perhaps by clubbing it over the head
with a mandrel? or a mandril?

grin

http://en.wikipedia.org/wiki/Mandrill
http://en.wikipedia.org/wiki/Mandrel

Antenna physical size
 

Owen Duffy wrote:
Ian White GM3SEK wrote in news:U5VH68Pl733HFA
:

Owen Duffy wrote:
Ian White GM3SEK wrote in
:

Alternatively, wind the wire onto a mandrill.
Or would that be a mandrel?

I've seen both spellings recommended in print, but winding wire onto a
mandrill will be far more entertaining.

Ah, when popularity displaces correctness!


Ian was making a Pun, Owen! Visualize winding wire onto that Mandrill!
Yikes!


- 73 de Mike N3LI -

Antenna physical size
 

Mike wrote:
I can bear it no longer. We have Art the English educated antenna expert
who cannot write the English language,and now a Scot who doesn't know that a
Mandrill is a West African Baboon.
If you wind Art's wire on a Baboon it is going to get seriously ****ed off.
From an elderly Pom in Aus.


Dijya ever notice how after a few times of having to explain it, a joke
just isn't as funny?


Well, I got it, Ian.......



- 73 de Mike N3LI -

Antenna physical size
 

Richard Harrison wrote:

I`ve learned not to quarrel with Terman. So, I reread the page 929
quotation. I posted it correctly. He did say a loop antenna responds
much less to the electric induction field than does a simple wire
antenna of comparable intercept area.

Even Mandrills know better than to quarrel with Terman....


- 73 de Mike N3LI -

Antenna physical size
 

"Ian White GM3SEK" wrote in message
...
Owen Duffy wrote:
Ian White GM3SEK wrote in
:

Alternatively, wind the wire onto a mandrill.

Or would that be a mandrel?


I've seen both spellings recommended in print, but winding wire onto a
mandrill will be far more entertaining.


what i have seen is a 'coil form' is something that remains inside the coil
once it is complete. a 'coil former' is a removable frame or device that
you wind the coil on and then remove. These can be for large coils that are
then supported by something else, like tank coils in amps. Or for coils
that are then put on a core that is built separately, as in a high voltage
power transformer.

Antenna physical size
 

Michael Coslo wrote:
I can bear it no longer. We have Art the English educated antenna
expert who cannot write the English language,and now a Scot who
doesn't know that a Mandrill is a West African Baboon.
If you wind Art's wire on a Baboon it is going to get seriously
****ed off. From an elderly Pom in Aus.


Dijya ever notice how after a few times of having to explain it, a joke
just isn't as funny?


Well, I got it, Ian.......

Thank you, Mike! I was losing the will to live.


--

73 from Ian GM3SEK 'In Practice' columnist for RadCom (RSGB)
http://www.ifwtech.co.uk/g3sek

Antenna physical size
 

Dave wrote:

"Ian White GM3SEK" wrote in message
...
Owen Duffy wrote:
Ian White GM3SEK wrote in
:

Alternatively, wind the wire onto a mandrill.

Or would that be a mandrel?


I've seen both spellings recommended in print, but winding wire onto a
mandrill will be far more entertaining.


OK, this time it's serious (well, mostly)...


The original meaning of "mandrel" seems to have been a rod-shaped tool,
onto which metal can be forged or glass can be mo(u)lded. The mandrel is
removed to leave a shaped cavity, and the mandrel can be used again.
This meaning is obviously very old, and would have crossed the Atlantic
with the Founding Fathers.

In the more recent context of coil winding, a mandrel is an object onto
which the wire can be wound. Again, the mandrel is always removed - it
is a tool, not part of the finished coil.

Some dictionaries note an alternative spelling, "mandril". This is an
old English dialect pronunciation, just like "chisil". (I don't know any
dialect-speaking blacksmiths, but can attest that "chisil" is still very
much alive.)

The confusion with "mandrill" comes from the fact that a convenient
mandrel of known size is the shank of... a drill.

The consequences of winding wire onto a mandrill - or indeed, onto a
ferret - are Nature's way of punishing engineers who can't spell.


Dave said:

what i have seen is a 'coil form' is something that remains inside the coil
once it is complete. a 'coil former' is a removable frame or device that
you wind the coil on and then remove. These can be for large coils that are
then supported by something else, like tank coils in amps. Or for coils
that are then put on a core that is built separately, as in a high voltage
power transformer.

That's completely different from British engineering usage. We don't use
"coil form" at all. "Coil former" almost always means something that
remains inside the completed coil. If it were meant to be removed, that
would have to be made clear from the context.


Cross-posted from rec.radio.amateur.etymology. We now return our antenna
readers to Prior Art.


--

73 from Ian GM3SEK 'In Practice' columnist for RadCom (RSGB)
http://www.ifwtech.co.uk/g3sek

Antenna physical size
 

Art Unwin wrote:
On Mar 18, 12:26 pm, Michael Coslo wrote:
Roy Lewallen wrote:
Mike Coslo wrote:
On Fri, 14 Mar 2008 11:57:41 -0700, Roy Lewallen wrote:
Richard Harrison wrote:
Build a small scale model that can be tested indoors and report its
characteristics. Antennas are scaleable.
That's more easily said than done. One of the critical characteristics
of a small antenna is loss. And to correctly replicate loss in a scaled
antenna requires scaling the conductivity of the conductors as the
square root of the frequency. To scale to a higher frequency requires
that the conductivity be better than the original. Unless the original
is made from lead and the scale factor moderate, this wouldn't be
possible.
If what I suspect is true, would not the coax also need to be scaled?
Dunno. What do you suspect?
I suspect that the antenna is a tuned circuit on top of coax, and it
needs that coax to radiate effectively. So just scaling the antenna
wouldn't translate to the same results?

- 73 de Mike N3LI -

If you are familiar with computor programming then why not model it
instead of repeating over and over again this transmission line
radiation theory.?


It comes up in the conversation Art, I only rinse and repeat as necessary.

I'm still trying to wrap my mind around the antenna, I'm nowhere near
ready to model it. So as to not make any ignorant mistakes, the antenna
is counter-wound inductors, correct? and they are concurrently wound, as
in they sort of weave against each other? And this is a full wave
antenna? Do you use enameled wire, or what is the insulation? I'm
assuming that this might be important in regards to VF.

- 73 de Mike N3LI -

Antenna physical size
 

On Mar 19, 7:27 am, Michael Coslo wrote:
Art Unwin wrote:
On Mar 18, 12:26 pm, Michael Coslo wrote:
Roy Lewallen wrote:
Mike Coslo wrote:
On Fri, 14 Mar 2008 11:57:41 -0700, Roy Lewallen wrote:
Richard Harrison wrote:
Build a small scale model that can be tested indoors and report its
characteristics. Antennas are scaleable.
That's more easily said than done. One of the critical characteristics
of a small antenna is loss. And to correctly replicate loss in a scaled
antenna requires scaling the conductivity of the conductors as the
square root of the frequency. To scale to a higher frequency requires
that the conductivity be better than the original. Unless the original
is made from lead and the scale factor moderate, this wouldn't be
possible.
If what I suspect is true, would not the coax also need to be scaled?
Dunno. What do you suspect?
I suspect that the antenna is a tuned circuit on top of coax, and it
needs that coax to radiate effectively. So just scaling the antenna
wouldn't translate to the same results?

- 73 de Mike N3LI -

If you are familiar with computor programming then why not model it
instead of repeating over and over again this transmission line
radiation theory.?

It comes up in the conversation Art, I only rinse and repeat as necessary.

I'm still trying to wrap my mind around the antenna, I'm nowhere near
ready to model it. So as to not make any ignorant mistakes, the antenna
is counter-wound inductors, correct? and they are concurrently wound, as
in they sort of weave against each other? And this is a full wave
antenna? Do you use enameled wire, or what is the insulation? I'm
assuming that this might be important in regards to VF.

- 73 de Mike N3LI -

I think you should forget the whole idea. We have another expert
on line that can voutch for the fact that it is just a dummy load.
He joins the majority and I am only one,.....who actually has one no
less.!
Art

Antenna physical size
 

Art Unwin wrote:
On Mar 19, 7:27 am, Michael Coslo wrote:

I'm still trying to wrap my mind around the antenna, I'm nowhere near
ready to model it. So as to not make any ignorant mistakes, the antenna
is counter-wound inductors, correct? and they are concurrently wound, as
in they sort of weave against each other? And this is a full wave
antenna? Do you use enameled wire, or what is the insulation? I'm
assuming that this might be important in regards to VF.

- 73 de Mike N3LI -

I think you should forget the whole idea. We have another expert
on line that can voutch for the fact that it is just a dummy load.
He joins the majority and I am only one,.....who actually has one no
less.!


What up Art? I'm trying to find out what the idea is behind this
antenna, not disrespect it.

- 73 de Mike N3LI -

Antenna physical size
 

On Mar 19, 1:50 pm, Michael Coslo wrote:
Art Unwin wrote:
On Mar 19, 7:27 am, Michael Coslo wrote:
I'm still trying to wrap my mind around the antenna, I'm nowhere near
ready to model it. So as to not make any ignorant mistakes, the antenna
is counter-wound inductors, correct? and they are concurrently wound, as
in they sort of weave against each other? And this is a full wave
antenna? Do you use enameled wire, or what is the insulation? I'm
assuming that this might be important in regards to VF.

- 73 de Mike N3LI -

I think you should forget the whole idea. We have another expert
on line that can voutch for the fact that it is just a dummy load.
He joins the majority and I am only one,.....who actually has one no
less.!

What up Art? I'm trying to find out what the idea is behind this
antenna, not disrespect it.

- 73 de Mike N3LI -

I have use std house wiring,enamelled magnet wire and simple buried
dog wire.
which I believe has the lowest insulation. Min wire I have used is #22
because the wire is not meant to support anything so 100%
of fused value seems to be o.k.
I have taken the windings off of the former but it is lacking in
strength.
I am using a wood lathe so that I can wind at 90 overlap of the wire
which will leave small holes
and will be stronger.
I made a machine to do this in the U.k. before I came over which had
no holes and was made of glass fibre tape.
I sold the machine which I used for lampshades before I came ove.
Prior to that shades were of monofiliament wound in single direction.
The machine was really for making an equivalent fuel containers on
the Atlas rocket so I made one for myself out of bycycle chain and
infra red heaters and mad some pocket money.
All of these I have tuned up with 100 watts

Antenna physical size
 

On Mar 19, 2:41 pm, Art Unwin wrote:
On Mar 19, 1:50 pm, Michael Coslo wrote:



Art Unwin wrote:
On Mar 19, 7:27 am, Michael Coslo wrote:
I'm still trying to wrap my mind around the antenna, I'm nowhere near
ready to model it. So as to not make any ignorant mistakes, the antenna
is counter-wound inductors, correct? and they are concurrently wound, as
in they sort of weave against each other? And this is a full wave
antenna? Do you use enameled wire, or what is the insulation? I'm
assuming that this might be important in regards to VF.

- 73 de Mike N3LI -

I think you should forget the whole idea. We have another expert
on line that can voutch for the fact that it is just a dummy load.
He joins the majority and I am only one,.....who actually has one no
less.!

What up Art? I'm trying to find out what the idea is behind this
antenna, not disrespect it.

- 73 de Mike N3LI -

I have use std house wiring,enamelled magnet wire and simple buried
dog wire.
which I believe has the lowest insulation. Min wire I have used is #22
because the wire is not meant to support anything so 100%
of fused value seems to be o.k.
I have taken the windings off of the former but it is lacking in
strength.
I am using a wood lathe so that I can wind at 90 overlap of the wire
which will leave small holes
and will be stronger.
I made a machine to do this in the U.k. before I came over which had
no holes and was made of glass fibre tape.
I sold the machine which I used for lampshades before I came ove.
Prior to that shades were of monofiliament wound in single direction.
The machine was really for making an equivalent fuel containers on
the Atlas rocket so I made one for myself out of bycycle chain and
infra red heaters and mad some pocket money.
All of these I have tuned up with 100 watts

Why not just wind a mirror image on your wlky talky antenna:
That way you are not using your body as a heat sink!s

Antenna physical size
 

Owen Duffy wrote:
Ian White GM3SEK wrote in
:

Alternatively, wind the wire onto a mandrill.

Or would that be a mandrel?

The hard part of winding it on a mandrill is getting it to stand still.

Dave K8MN

Antenna physical size
 

"Art Unwin" wrote in message
...
On Mar 19, 2:41 pm, Art Unwin wrote:

this must be the explanation for art's antenna design prowess, and probably
a bunch of the other less than coherent contributors in here.
http://science.slashdot.org/article....11242&from=rss

Antenna physical size
 

Dave Heil wrote:
Owen Duffy wrote:

Ian White GM3SEK wrote in
:

Alternatively, wind the wire onto a mandrill.


Or would that be a mandrel?


The hard part of winding it on a mandrill is getting it to stand still.

That's why you need the mandrel.. you whack the mandrill over the head
(pretty hard), then, while it's stunned, you quickly wind the wire on it.

Of course, you need to move fast to remove your winding before the
mandrill regains consciousness. They're pretty big and strong, and have
BIG teeth.


On the other hand, if you are winding on a Mandrell, they understand
spoken language. You might be able to just explain what you're doing,
and she (or he) might sit still for the process. Mandrells also have
much smaller teeth than mandrills, and aren't nearly as strong, so if
they do object during the winding process, your risk of injury is less.

Antenna physical size
 

On Mar 11, 10:29 am, Cecil Moore wrote:
Art Unwin wrote:
If Kraus said "The radiation is perpendicular to the accelleration"
then the book is worthless.

Balanis says, speaking of an infinitesimal dipole:
"Integrating the complex Poynting vector over a closed
sphere, ... results in the power (real and imaginary)
directed in the radial direction. Any transverse
components of power density, ... will not be captured by
the integration even though they are part of the overall
power."

Apparently, Kraus' assertion is a result of the integration
math and does not necessarily correspond to reality.
--
73, Cecil http://www.w5dxp.com

Another point to reckon with is the tilted folded dipole
The experiment the Naval departgment under took when comparing
antennas.
The results showed that antennas tipped away from parallelism to the
ground
provided best results for their use which concentrated on receiving.
All existing antennas were removed and replaced by tilted radiators.
Thus their tests showed that tipped radiators was not a "myth" as
stated by this group
and also radiationis not primarily at right angles to a radiator.Is
the Navy at fault by not conforming
to Kraus's and other expert teachings and aligning themselves to
facts attained in the field.
As Reagan stated "Trust but verify" The same goes for students who
suck up what the experts
and professors state without verifying from first principles. Choice
of answers will
allow memorisation to pass the exam but not to arrive at the cusp of
new discoveries!
Art Unwin...KB9MZ..xg (uk)

Antenna physical size
 

Art wrote:
"If Kraus said "The radiation is perpendicular to the acceleration" then
the book is worthless."

Art scoffs at Kraus and Art scoffs at experience with antenna
orientation for best reception. So that readers aren`t mislead, olease
refer to page one of Terman`s 1955 opus:

"---radio waves. travel with the velocity of light and consist of
magnetic and electric fields at right angles to each other and also at
right angles to the direction of travel." Then check page 923:

"--- E is the field strength of the wave in volts per meter, Psi is the
angle between the plane of polarization and the wire in which the
voltage is induced" ---It will be observed that the quantity E cos Psi
cos theta is the component of the field strength which has a wavefront
parallel to the antenna and is polarized in the same plane as the
antenna."

He who scoffs at Terman is at great peril.

Best regards, Richard Harrison, KB5WZI

Antenna physical size
 

On Mar 25, 12:36 pm, (Richard Harrison)
wrote:
Art wrote:

"If Kraus said "The radiation is perpendicular to the acceleration" then
the book is worthless."

Art scoffs at Kraus and Art scoffs at experience with antenna
orientation for best reception. So that readers aren`t mislead, olease
refer to page one of Terman`s 1955 opus:

"---radio waves. travel with the velocity of light and consist of
magnetic and electric fields at right angles to each other and also at
right angles to the direction of travel." Then check page 923:

"--- E is the field strength of the wave in volts per meter, Psi is the
angle between the plane of polarization and the wire in which the
voltage is induced" ---It will be observed that the quantity E cos Psi
cos theta is the component of the field strength which has a wavefront
parallel to the antenna and is polarized in the same plane as the
antenna."

He who scoffs at Terman is at great peril.

Best regards, Richard Harrison, KB5WZI

But ham radio and the Navy have proved him wrong with the T2FD
testing !
Computor programs designed around Maxwell's laws also prove him wrong.
I suggest you study the under pinnings, if any, by Terman of that
particular point
and then share the "proof" with all of us. Again, you have two vectors
for the
electric and magnetic field at right angles to each other. Using your
own brain
please tell as where the curl vector MUST be to prove your case.
Ofcourse you can
read a lot of books and select a diagram of the vectors involved that
solidifies your position
but I don't think you will find one anywhere. Your HIT and MYTH
aproaches just doesn't work out.

Antenna physical size
 

Richard Harrison wrote:
He who scoffs at Terman is at great peril.

If radiation was *only* perpendicular to the antenna,
wouldn't the beam width be fixed to the length of
the antenna? Wouldn't cloverleaf patterns be
impossible? What am I missing?
--
73, Cecil http://www.w5dxp.com