On Wed, 13 Jun 2007 10:38:04 -0700, Jim Lux
wrote:

Buck wrote:
On Mon, 11 Jun 2007 22:00:14 -0700, "Alfred Lorona"
wrote:


Is there a site that explores/explains the latest theories on one way
propagation? The ARRL antenna book is not much help on the subject.

tnx, AL



One way Propagation: The cause of one-way propagation is a station who
uses power to overcome antenna losses. the station can be heard but
cannot hear.

or they are ignoring stations they don't want to talk to....

perhaps on VHF and higher where receiver noise dominates. On lower
frequencies, where atmospheric noise dominates, one could tolerate quite
a bit of loss in the antenna/feedline and still "hear" exactly the same,
since the SNR at the antenna dominates the overall situation.

A nice practical example, in use in many HF commercial, government, and
utility type stations, would be the use of an antenna that has been
broadbanded by use of lossy elements (e.g. the terminated folded dipole
sorts of things). You might take a 6-8 dB hit in the antenna loss, which
you make up by jacking up the Tx power by 6-8 dB, but you also don't
have to worry about tuners, etc. This would be particularly useful if
you were doing ALE or frequency hopping.

and actually, my original comment was tounge-in-cheek. I sent before
realizing I hadn't added the wink.


--
73 for now
Buck, N4PGW

www.lumpuckeroo.com

"Small - broadband - efficient: pick any two."

On 13 Jun, 16:32, Buck wrote:
On Wed, 13 Jun 2007 10:38:04 -0700, Jim Lux
wrote:

Buck wrote:
On Mon, 11 Jun 2007 22:00:14 -0700, "Alfred Lorona"
wrote:

Is there a site that explores/explains the latest theories on one way
propagation? The ARRL antenna book is not much help on the subject.

tnx, AL

One way Propagation: The cause of one-way propagation is a station who
uses power to overcome antenna losses. the station can be heard but
cannot hear.

or they are ignoring stations they don't want to talk to....



perhaps on VHF and higher where receiver noise dominates. On lower
frequencies, where atmospheric noise dominates, one could tolerate quite
a bit of loss in the antenna/feedline and still "hear" exactly the same,
since the SNR at the antenna dominates the overall situation.

A nice practical example, in use in many HF commercial, government, and
utility type stations, would be the use of an antenna that has been
broadbanded by use of lossy elements (e.g. the terminated folded dipole
sorts of things). You might take a 6-8 dB hit in the antenna loss, which
you make up by jacking up the Tx power by 6-8 dB, but you also don't
have to worry about tuners, etc. This would be particularly useful if
you were doing ALE or frequency hopping.

and actually, my original comment was tounge-in-cheek. I sent before
realizing I hadn't added the wink.

--
73 for now
Buck, N4PGW

www.lumpuckeroo.com

"Small - broadband - efficient: pick any two."

Surprises me that nobody has made reference to dissimilar antennas
as possible contributors, especially if one was dual polarised.
Also have heard that one station had to turn his antenna some
40 degrees to achieve parity. Then there is the situation
where local terrain( knife edge cliff top) provides one way
transmission So I am inclined to say that parity is achieved
if conditions at both ends are the same or equivalent

Art wrote:
"Surprises me that nobody has made reference to dissimilar abtennas as
possible contributors----."

Yes. The original questioner, Al Lorona did not rule out separate
antennas for transmission and reception as a possible cause of "one way
propagation".

Art has ridiculed books as sources of answers for questions such as
this, but often they give reliable answers. Kraus writes on page 252 of
his 1950 edition of "Antennas":
"If an emf is applied at the terminals of an antenna A and the current
measured at the terminals of another antenna B, then an equal current
(in both amplitude and phase) will be obtained at the terminals of
antenna A if the same emf is applied to the terminals of antenna B, It
is assumed that the emfs are of the same frequency and that the medium
is linear, passive, and also isotropic."

I think reciprocity is why Al doesn`t find sites about one way
propagation.

Best regards, Richard Harrison, KB5WZI

On 14 Jun, 04:55, (Richard Harrison) wrote:
Art wrote:

"Surprises me that nobody has made reference to dissimilar abtennas as
possible contributors----."

Yes. The original questioner, Al Lorona did not rule out separate
antennas for transmission and reception as a possible cause of "one way
propagation".

Art has ridiculed books as sources of answers for questions such as
this, but often they give reliable answers.

No I don't !
I ridicule those who cherry pick a line from a book
and then use it out of context. The original author
provides a whole chapter on a particular subject and
then some one comes along and parrots a single line.
If you are slow in understanding subjects then such
answers magnify your inadequatecy



regards, Richard Harrison, KB5WZI

"Richard Harrison" wrote in message
...

Kraus writes on page 252 of
his 1950 edition of "Antennas":
"If an emf is applied at the terminals of an antenna A and the current
measured at the terminals of another antenna B, then an equal current
(in both amplitude and phase) will be obtained at the terminals of
antenna A if the same emf is applied to the terminals of antenna B, It
is assumed that the emfs are of the same frequency and that the medium
is linear, passive, and also isotropic."


That is fine and guaranteed in ideal cases or when antennas "see" each
other. But when signals are going through the ionosphere and considerable
distances, things don't jive exactly like that. I had cases when at
particular opening I would receive say OK2 at the lower angle and UA0 at
higher angle, which is not "normal" but on transmit the situation would be
just opposite, indicating that ionosphere (ether :-) would be behaving
differently at the ends of the paths. This definitely was not the result of
the local noise masking signals "explaining" disparity.
Again, I summarized my finding in my article in CQ. I came to the conclusion
that about 60% of propagating is not reciprocal RX vs. TX. That was done
using my stacked Razor antennas. Believe it or not, but that is like person
with reading glasses (dipole) will not see what person with telescope
(Razors) can see.

73 Yuri, www.K3BU.us

On 14 Jun, 11:47, "Yuri Blanarovich" wrote:
"Richard Harrison" wrote in message

...

Kraus writes on page 252 of

his 1950 edition of "Antennas":
"If an emf is applied at the terminals of an antenna A and the current
measured at the terminals of another antenna B, then an equal current
(in both amplitude and phase) will be obtained at the terminals of
antenna A if the same emf is applied to the terminals of antenna B, It
is assumed that the emfs are of the same frequency and that the medium
is linear, passive, and also isotropic."

That is fine and guaranteed in ideal cases or when antennas "see" each
other. But when signals are going through the ionosphere and considerable
distances, things don't jive exactly like that. I had cases when at
particular opening I would receive say OK2 at the lower angle and UA0 at
higher angle, which is not "normal" but on transmit the situation would be
just opposite, indicating that ionosphere (ether :-) would be behaving
differently at the ends of the paths. This definitely was not the result of
the local noise masking signals "explaining" disparity.
Again, I summarized my finding in my article in CQ. I came to the conclusion
that about 60% of propagating is not reciprocal RX vs. TX. That was done
using my stacked Razor antennas. Believe it or not, but that is like person
with reading glasses (dipole) will not see what person with telescope
(Razors) can see.

73 Yuri,www.K3BU.us

I can go along with that! As the different layers form, rise and form
at
different rates with the sunrise and sunset it is difficult to lean on
the idea that
all radiation is reciprocal. If one sees the return curve of radiation
formed as a
layer is met it is also difficult to understand how the layer
is consistent in density, shape and altitude. When wind shear was
mentioned it reminded me
of the situation where skin depth on the ocean surface varies with
climatic conditions
when dealing with VLF. Why would a ducting signal pierce a layer at
one point and
continue to skip at other points if layer density was constant? True,
one can feel confident
of reprocity if communication is ongoing which is all they care
about.
But if one thinks of the possibilites why a CQ does not meet with a
responce
as a means of determine the validy of one way
propagation............!!!
Art

On 14 Jun, 12:43, art wrote:
On 14 Jun, 11:47, "Yuri Blanarovich" wrote:





"Richard Harrison" wrote in message

...

Kraus writes on page 252 of

his 1950 edition of "Antennas":
"If an emf is applied at the terminals of an antenna A and the current
measured at the terminals of another antenna B, then an equal current
(in both amplitude and phase) will be obtained at the terminals of
antenna A if the same emf is applied to the terminals of antenna B, It
is assumed that the emfs are of the same frequency and that the medium
is linear, passive, and also isotropic."

That is fine and guaranteed in ideal cases or when antennas "see" each
other. But when signals are going through the ionosphere and considerable
distances, things don't jive exactly like that. I had cases when at
particular opening I would receive say OK2 at the lower angle and UA0 at
higher angle, which is not "normal" but on transmit the situation would be
just opposite, indicating that ionosphere (ether :-) would be behaving
differently at the ends of the paths. This definitely was not the result of
the local noise masking signals "explaining" disparity.
Again, I summarized my finding in my article in CQ. I came to the conclusion
that about 60% of propagating is not reciprocal RX vs. TX. That was done
using my stacked Razor antennas. Believe it or not, but that is like person
with reading glasses (dipole) will not see what person with telescope
(Razors) can see.

73 Yuri,www.K3BU.us

I can go along with that! As the different layers form, rise and form
at
different rates with the sunrise and sunset it is difficult to lean on
the idea that
all radiation is reciprocal. If one sees the return curve of radiation
formed as a
layer is met it is also difficult to understand how the layer
is consistent in density, shape and altitude. When wind shear was
mentioned it reminded me
of the situation where skin depth on the ocean surface varies with
climatic conditions
when dealing with VLF. Why would a ducting signal pierce a layer at
one point and
continue to skip at other points if layer density was constant? True,
one can feel confident
of reprocity if communication is ongoing which is all they care
about.
But if one thinks of the possibilites why a CQ does not meet with a
responce
as a means of determine the validy of one way
propagation............!!!
Art- Hide quoted text -

- Show quoted text -

Another thought. When using NEC style programs on antennas we see a
common TOA
regardles of the mix of polarization. We do know that common
polarisation
can be created on reflection from the ionisphere but I believe the
trajectory
of radiation changes depending on the influence and density of the
terrain
on the polarization when transmitting. If this were to be correct we
could
well be examining two or more separate trajectories that could dispel
the idea
of reprocity. Remember that North /South lines of electromagnetism
assist
such that it can be noticed in communications so its implications
cannot
be ruled out with respect to one way propagation.
Fortunately new books are regularly printed as science moves on where
old books and ideas printed in them finish up in the ground with the
generation that coveted them.
Art

Yuri, Kk3BU wrote:
"But when signals are going throug the ionosphere and considerable
distances, things don`t jive exactly like that."

Yuri is nost likely correct. Even line-of-sight paths experience strange
things.

Isotropic material has the same characteristics along any axis. Kraus
left himself an out by saying:
"It is assumed that the emfs are of the same frequency, and the medium
is linear, passive, and also isotropic." I think he implies that
reciprocity may not rule when the medium is as screwed up as it often is
in the ionosphere.

I had one nonreciprocal microwave path among a countless total in my
experience. It connected a rooftop in downtown Houston with the
company`s aircraft hanger at Houston International (now Bush) Airport.
The path ran from the company headquarters northward right up the street
in a canyon between skyscrapers, several of which had more than our 33
floors. The signal at the airport was stronger than that at headquarters
by several dB. As we had more than 40 dB fade margin in both directions,
I scratched my head but lost no sleep.

I have HF radio experience between Germany and Portugal while working in
shortwave broadcasting. We used HF for an order-wire between locations.
Signal strengths and path losses seemed to be nearly identical in both
directions. Transmitters were 3.5 KW Collins Auto-Tune all-purpose
AM/CW/MCW with a rotary phone dial to select mode and frequency.
Receivers were Hammerlund SP 600Xs.

Best regards, Richard Harrison, KB5WZI

On 14 Jun, 13:33, (Richard Harrison) wrote:
Yuri, Kk3BU wrote:

"But when signals are going throug the ionosphere and considerable
distances, things don`t jive exactly like that."

Yuri is nost likely correct. Even line-of-sight paths experience strange
things.

Isotropic material has the same characteristics along any axis. Kraus
left himself an out by saying:
"It is assumed that the emfs are of the same frequency, and the medium
is linear, passive, and also isotropic." I think he implies that
reciprocity may not rule when the medium is as screwed up as it often is
in the ionosphere.

I had one nonreciprocal microwave path among a countless total in my
experience. It connected a rooftop in downtown Houston with the
company`s aircraft hanger at Houston International (now Bush) Airport.
The path ran from the company headquarters northward right up the street
in a canyon between skyscrapers, several of which had more than our 33
floors. The signal at the airport was stronger than that at headquarters
by several dB. As we had more than 40 dB fade margin in both directions,
I scratched my head but lost no sleep.

I have HF radio experience between Germany and Portugal while working in
shortwave broadcasting. We used HF for an order-wire between locations.
Signal strengths and path losses seemed to be nearly identical in both
directions. Transmitters were 3.5 KW Collins Auto-Tune all-purpose
AM/CW/MCW with a rotary phone dial to select mode and frequency.
Receivers were Hammerlund SP 600Xs.

Best regards, Richard Harrison, KB5WZI

You just proved my point! You 'cherry picked' a line to quote from
Kraus
to give yourself some sort of authority. The quote starts off with
"It is assumed.." Now you have added "I think"..... and now you
suggest that he "Kraus" "I think he implies" he meant something else.
You then went off subject thinking about the old days when Ham
radio was for real hams before your mind finally succumbed to sleep
again.What do you think you achieved with that posting that
you snitched? Does it reflect on the real you? "Signals strengths
and path losses seemed to be nearly identical" you also state.
Have you now switched back to "reprocity" or are you meaning
something else again? Possibly leaving yourself an "out"

Art wrote:
"What do you think you achieved with that posting that you snitched?"

I gave the book and the page number of an expert`s opinion that
reprocity usually rules with antennas.
Kraus says it again in the 3rd edition of "Antennas" on page 829:
"The transmitting and receiving patterns are the same."

"The power flow is the same either way."

Very plain talk.

Art doesn`t like my commentary. That`s his prerogative.

I`m not a typist so I avoid repeating where I can, but I try to be
accurate.

I believe there are nonreciprocal paths because I`ve seen one as I wrote
in my earlier posting.

I`ve measured hundreds of microwave paths using very accurate
instruments. Almost always they were completely reciprocal. I`ve seen as
many HF paths but rarely used anything beyond an "S" meter to measure
them. Not much point when the medium itself varies so much.You need
accuracy to prove a new antenna though. I`ve done that by comparison
weith a known standard. I switched between the antennas every 5 minutes
while continuously recording the distant signal strength. I then
averaged the results and compared them. The results were as predicted by
the calculations.

Best regards, Richard Harrison, KB5WZI