"AI4QJ" wrote in
:

....
Are you talking about the possibility of Art communicating with other
people who are transmitting on similar helical circularly polarized
antennas where CW vs CCW direction must be considered? I dismissed

If this is his compact wonder, it is probably not an axial mode helical.
(I don't know that one could ever describe an axial mode helical as
'compact'.)

Normal mode helicals deliver linear polarisation.

this possibility entirely. Most hams's signals arrive either veritcal,
norizontal or somewhere in between (not rotating) originating at a
linear polarized source. Is he communicating with satellites? I really
haven't heard of helix antennas on the HF bands other than the Unwin
compact model. If so, then yes, you can only switch the feedpoint to

Normal mode helicals are commonly used on HF.

change from CW to CCW and that can make a BIG difference in gain. The
probability of Art finding another HF helical to QSO with should be
negligible to null. Satellites are another matter.

Owen

On Mar 16, 12:55 am, Owen Duffy wrote:
"AI4QJ" wrote :

...

Are you talking about the possibility of Art communicating with other
people who are transmitting on similar helical circularly polarized
antennas where CW vs CCW direction must be considered? I dismissed

If this is his compact wonder, it is probably not an axial mode helical.
(I don't know that one could ever describe an axial mode helical as
'compact'.)

Normal mode helicals deliver linear polarisation.

this possibility entirely. Most hams's signals arrive either veritcal,
norizontal or somewhere in between (not rotating) originating at a
linear polarized source. Is he communicating with satellites? I really
haven't heard of helix antennas on the HF bands other than the Unwin
compact model. If so, then yes, you can only switch the feedpoint to

Normal mode helicals are commonly used on HF.

change from CW to CCW and that can make a BIG difference in gain. The
probability of Art finding another HF helical to QSO with should be
negligible to null. Satellites are another matter.

Owen

See recent posting on E ham
Art

Art wrote:
"Normal mode helicals are commonly used on HF."

Yes. Such antennas include small diameter coils making up solenoids. The
turns act as small stacked loops.

A small loop acts as a short dipole but with its E and H fields
interchanged. See page 58 of the 3rd edition of "Antennas" by Kraus,
Marthefka, et al.

Best regards, Richard Harrison, KB5WZI

On Mar 16, 2:48 pm, (Richard Harrison)
wrote:
Art wrote:

"Normal mode helicals are commonly used on HF."

Yes. Such antennas include small diameter coils making up solenoids. The
turns act as small stacked loops.

A small loop acts as a short dipole but with its E and H fields
interchanged. See page 58 of the 3rd edition of "Antennas" by Kraus,
Marthefka, et al.

Best regards, Richard Harrison, KB5WZI

I did not say that. The quote is from somewhere else.
I am sure that he will be happy about the facts that you
have revealed to him as a personal favor and a book
that he can read up for himself what "Normal mode" means
Then explain it to you so you understand what you read
In the mean time I will try loading up a solenoid on 20 M
to see how many people are using them..

I apologize to Art Unwin. It was Owen Duffy who wrote:
"Normal mode helicals are commonly used on HF."

A normal mode helical antenna radiates perpendicularly to the axis of
the helix. The axial mode helix antenna invented by John Kraus radiates
in the direction of the axis of the helix.

Best regards, Richard Harrison, KB5WZI

"Owen Duffy" wrote in message
...
"AI4QJ" wrote in
:

...
Are you talking about the possibility of Art communicating with other
people who are transmitting on similar helical circularly polarized
antennas where CW vs CCW direction must be considered? I dismissed

If this is his compact wonder, it is probably not an axial mode helical.
(I don't know that one could ever describe an axial mode helical as
'compact'.)

Normal mode helicals deliver linear polarisation.

this possibility entirely. Most hams's signals arrive either veritcal,
norizontal or somewhere in between (not rotating) originating at a
linear polarized source. Is he communicating with satellites? I really
haven't heard of helix antennas on the HF bands other than the Unwin
compact model. If so, then yes, you can only switch the feedpoint to

Normal mode helicals are commonly used on HF.

change from CW to CCW and that can make a BIG difference in gain. The
probability of Art finding another HF helical to QSO with should be
negligible to null. Satellites are another matter.

Owen

Hi Owen

I have no disagreement with your thoughts. I do want to point out that
the short helical antenna named Quad Helix does give good CP normal to the
helix axis.

Jerry KD6JDJ

"Jerry" wrote in
news:dniDj.714$Nr1.510@trnddc01:

....
Hi Owen

I have no disagreement with your thoughts. I do want to point out
that
the short helical antenna named Quad Helix does give good CP normal to
the helix axis.

Hi Jerry,

John Kraus' explanation of "normal mode" is where the radiation normal to
the helix axis dominates. On that basis, the Quad Helix (which he
discusses in his book) is neither an axial mode helix nor a normal mode
helix, it is large enough that it has significant radiation both normal
and axial, but not large enough to be dominated by the axial lobe, and it
is a multi-filar helix which allows CP normal to the helix axis.

The Quadrifilar Helix is an interesting antenna, and I was aware of your
particular interest from previous reading.

I don't know of a mono-filar normal mode helix that gives CP, but I
expect that two of them with phased feeds could be used in the same way
as crossed dipoles.

We are of course all guessing what Art had in mind, there is a conspicous
and familiar lack of coherent detail.

Owen

"Owen Duffy" wrote in message
...
"Jerry" wrote in
news:dniDj.714$Nr1.510@trnddc01:

...
Hi Owen

I have no disagreement with your thoughts. I do want to point out
that
the short helical antenna named Quad Helix does give good CP normal to
the helix axis.

Hi Jerry,

John Kraus' explanation of "normal mode" is where the radiation normal to
the helix axis dominates. On that basis, the Quad Helix (which he
discusses in his book) is neither an axial mode helix nor a normal mode
helix, it is large enough that it has significant radiation both normal
and axial, but not large enough to be dominated by the axial lobe, and it
is a multi-filar helix which allows CP normal to the helix axis.

The Quadrifilar Helix is an interesting antenna, and I was aware of your
particular interest from previous reading.

I don't know of a mono-filar normal mode helix that gives CP, but I
expect that two of them with phased feeds could be used in the same way
as crossed dipoles.

We are of course all guessing what Art had in mind, there is a conspicous
and familiar lack of coherent detail.

Owen

Hi Owen

Art who??

Again, I am in full agreement with you on the limited application of nthe
term "Normal" to the radiation of a helix. In addition, I suspect there is
little need to elaborate, but, if a person had need, he could make a
bi-directional CP radiator from 1/2 of a Quad helix.

Jerry KD6JDJ