Use your own thread to ask for assistance on your question.
Be prepared to answer why you are requesting this personal service .
I asked a question on this thread with respect to the main advantage
for hams that linear
polarization has over CP. I have no resistance to change if it can be
justified. I see
that it can pick up signals that linear antennas cannot hear because
of a 30 db attenuation
where as CP has only a 3 db attenuation!
So what is it on the other side of the coin is what this thread is
posing to those who are familiar with respect to radiators.

Cross polarization can be used to provide isolation for duplex links or
co-channel sharing.


I think that you are looking at it from the wrong point of view. CP does not
have 3dB attenuation, but a linearly polarized signal received on a CP
antenna will be 3db down (whether that be H, V or slant).

So for amateur use CP is useful in that with another CP station multipath
due to reflections will be reduced (reflections taking on the opposite hand
CP and thus attenuated). However, if a CP antenna is used to receive H or V
you may well not see the full 3dB reduction due to twisting of the
polarization on the path. In fact over some paths the signal on a CP antenna
will be better than on a linearly polarized antenna due the a greater
attenuation due to polarization twisting.

Of course the best of both worlds is to have a crossed yagi with a phase
switching box so that you can select CP (both hands) H, V or slant 45 both
ways.

Commercially (terrestrially) I don't think that CP is used much except
perhaps on microwave point to point links.

Jeff

snpOn Aug 11, 10:16*am, "Jeff" wrote:


Of course the best of both worlds is to have a crossed yagi with a phase
switching box so that you can select CP (both hands) H, V or slant 45 both
ways.

Jeff, I want the" best of both" worlds but before one jumps one needs
to know the advantages and disadvantages of both first. To be frank, I
do not know what happens to all signals when they are reflected
including the reflection off the ground to a receiver or a direct hit
on the receiver from our upper layers so I have no way of undertaking
a comparison. Now most hams are resistant to change or will only
follow the majoratory thus the questions "who has the majoratory". For
me I see CP as an ideal approach for smaller volume antennas which is
the "holy grail" for hams, but one has to determine if smaller is
important enough to overide possible faults.Now I have a whip antenna
( no ground plane) on my tower that is CP for top band but the bands
are poor it is difficult to determine its worth especially since
there are no similar radiators out there. So I fall back and ask for
"what is known already" as there is no point in re inventing the
wheel. Is that so bad?
Now before the catwalling about the possibility of having a whip (a 5
foot pole) for top band
my intention is to release all that during the next month. So lets not
waste energy in side tracking comments and stay on the essence of this
thread. Remember the last time I intended to release it was evident
that most did not want to hear it........ so I went along !





Commercially (terrestrially) I don't think that CP is used much except
perhaps on microwave point to point links.

Jeff

You need to read up on it. It does have it's uses and I know hams that use
it. Usually by Satellite guys that talk to mobiles too. It gets used by
quite a few commercial broadcast FM stations. The theory is that a mobile
antenna will hear either the main path or reflected path but to a lesser
extent, both so multi-path distortion is minimized. Typically the
reflection cause a reversal of polarization. There is no substitute for
talking to the far station in whatever polarity is agreed on.

On Aug 11, 12:30*pm, "JB" wrote:
You need to read up on it. *It does have it's uses and I know hams that use
it. *Usually by Satellite guys that talk to mobiles too. *It gets used by
quite a few commercial broadcast FM stations. *The theory is that a mobile
antenna will hear either the main path or reflected path but to a lesser
extent, both so multi-path distortion is minimized. *Typically the
reflection cause a reversal of polarization. *There is no substitute for
talking to the far station in whatever polarity is agreed on.

You bet that they have to read up on it.
For those who consider themselves experts and others idiots.
There is some sort of federation for antenna builders and the
President of that group states we will have a disaster on our hands if
we do not come up with a new technology for what is required in 5
years. Apparently cell phones will be divided into three bands and the
big boys want access to all. This means that they need three separate
antennas on the cell phone to cater for all (his words). They don't
like that idea because it means three antennas in close proximation to
each other. The response to that challenge is to group together the
research facilities to find a "new" technology if ever there is one. A
lot of money at stake and it is for any of you that are knowledgable
in the field to apply for.
Those who are really "knowledgable" already know there is no "new"
technology only the one that they use and they all have researched it
to death such that all the answers have been unfolded to them. It is
also too late to ask God to be a bit more fair and provides some
different options to what we already have.
All I ask of them is to share with the rest of us exactly what
happens to CP when it collides with anything in transit to a receiver.

On Aug 11, 4:24*pm, Art Unwin wrote:
different options to what we already have.
* *All I ask of them is to share with the rest of us exactly what
happens to CP when it collides with anything in transit to a receiver.

And the information was so shared.

Jimmie

JIMMIE wrote:
On Aug 11, 4:24 pm, Art Unwin wrote:
different options to what we already have.
All I ask of them is to share with the rest of us exactly what
happens to CP when it collides with anything in transit to a receiver.

And the information was so shared.

Jimmie

They split themselves from the conspiracy to keep Art un- and
misinformed. They will pay for that.

tom
K0TAR

On Aug 15, 7:27*pm, tom wrote:
JIMMIE wrote:
On Aug 11, 4:24 pm, Art Unwin wrote:
different options to what we already have.
* *All I ask of them is to share with the rest of us exactly what
happens to CP when it collides with anything in transit to a receiver.

And the information was so shared.

Jimmie

They split themselves from the conspiracy to keep Art un- and
misinformed. *They will pay for that.

tom
K0TAR

I am just waiting for his new contraption that is going to produce
circular polarized waves on 160M and you could haul it in the trunk of
your car. I hope that when I am as old as he says he is that I will
have morre interesting things to do wiith my time than tilt at
antennas.

Jimmie