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

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 -

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

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.?

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 -

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

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 -

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