First off I don't really believe in one way propagaiton unless someone
can convince me otherwise ? However, I am curious about a phenomenon
I've experienced with a number or radios and antennas over the years.
I've had eveything from a 4 element Yagi at 55 feet to the dipoles I'm
using now and lots of new transcievers. I work all CW and on occasion
I'll get a 599 signal report from the other station yet he's barely
copyable from my end. They all seem to be running the same 100 watts
or more that I'm using now and are using a dipole cut for the
frequency in use like I am or a G5RV etc. I wonder if anyone else has
observed this and/or has an explanation ? This has occured on new
transceivers too numerous to name over the years. So I know its not a
problem with a particular radio.

73 and Thanks in Advance

Gary K8IQ

On Wed, 16 Feb 2005 02:19:31 -0500, Gary wrote:

First off I don't really believe in one way propagaiton unless someone
can convince me otherwise ? However, I am curious about a phenomenon
I've experienced with a number or radios and antennas over the years.
I've had eveything from a 4 element Yagi at 55 feet to the dipoles I'm
using now and lots of new transcievers. I work all CW and on occasion
I'll get a 599 signal report from the other station yet he's barely
copyable from my end. They all seem to be running the same 100 watts
or more that I'm using now and are using a dipole cut for the
frequency in use like I am or a G5RV etc. I wonder if anyone else has
observed this and/or has an explanation ? This has occured on new
transceivers too numerous to name over the years. So I know its not a
problem with a particular radio.

73 and Thanks in Advance

Gary K8IQ

I have been thinking about that same thing. I hunt counties and
therefore talk to lots of mobiles. Many times I talk to the same
mobile in different locations. There are times I am received 59 and
hear 22. Other times I hear 59 and get a 22. Since there are many
mobiles throughout the country, I think I get a better picture of what
propagation looks like than I would if I were just making random
contacts. I live in the southeast and use a dipole, so for the most
part, communications are in the same direction.

Here is my theory, as unsound as it may be. Think of a station with
100 watts using a TV dish style antenna talking to a person using just
a dipole with 100 watts. The dipole user will hear a much stronger
signal. However, on HF, we don't use dishes. Or maybe we do...

We know the ionosphere affects propagation. It is assumed that
signals take the same path and therefore should have the same
strength, but I don't think so. If the ionosphere is dense (relative
to my frequency) behind and over my station, I may be using it as a
'dish' reflector. However, at your location, you may have a porous
ionosphere so rather than your signal being reflected, it is being
absorbed. The result is that I have an ERP of 200 watts and you reply
to me with an ERP of 20.

This is just my theory I have in my mind and it may be that it is more
full of holes than the ionosphere I put over your station in the
example.

But, for what it's worth....
73 for now.

Buck
N4PGW

--
73 for now
Buck
N4PGW

On 2005-02-16, Buck wrote:

We know the ionosphere affects propagation. It is assumed that
signals take the same path and therefore should have the same
strength, but I don't think so. If the ionosphere is dense (relative
to my frequency) behind and over my station, I may be using it as a
'dish' reflector. However, at your location, you may have a porous
ionosphere so rather than your signal being reflected, it is being
absorbed. The result is that I have an ERP of 200 watts and you reply
to me with an ERP of 20.

takeoff angle also plays a big part in this. One station may have a lower
angle and be making only 1 hop to the other station, while the other station
may have a higher angle and be hitting the first station via 2 hops --
resulting in some signal loss.

--
Alex / AB2RC
Linux is user friendly, however it is not idiot friendly

Alex, I believe that the problem occuring here is that many are using words
like refraction, reflection
as being interchangeable. I see a mountainside when operating close to as a
reflector though
it may well be an absorber too. Anything, both behind or in front of a
driven element is a diffractor, thus its length alone
with respect to the driver does not determine whether it reflects or not.
If one solely focusses on the typical yagi
then it is easy to talk in general terms which are not applicable to other
arrays which leads to erroneous
descriptions. It is quite easy to design an array where there are many
elements behind the driven element and many
would be of lengths both shorter and longer than the driven element but
because they are closely coupled they can represent a single, longer element
as coupled elements introduces quanlities other than simple physical
length..
Regards
Art

"AB2RC" wrote in message
...
On 2005-02-16, Buck wrote:

We know the ionosphere affects propagation. It is assumed that
signals take the same path and therefore should have the same
strength, but I don't think so. If the ionosphere is dense (relative
to my frequency) behind and over my station, I may be using it as a
'dish' reflector. However, at your location, you may have a porous
ionosphere so rather than your signal being reflected, it is being
absorbed. The result is that I have an ERP of 200 watts and you reply
to me with an ERP of 20.

takeoff angle also plays a big part in this. One station may have a lower
angle and be making only 1 hop to the other station, while the other
station
may have a higher angle and be hitting the first station via 2 hops --
resulting in some signal loss.

--
Alex / AB2RC
Linux is user friendly, however it is not idiot friendly

On Wed, 16 Feb 2005 19:28:02 GMT, AB2RC
wrote:

takeoff angle also plays a big part in this. One station may have a lower
angle and be making only 1 hop to the other station, while the other station
may have a higher angle and be hitting the first station via 2 hops --
resulting in some signal loss.


I can see this.
--
73 for now
Buck
N4PGW

Buck wrote:
Many times I talk to the same
mobile in different locations. There are times I am received 59 and
hear 22. Other times I hear 59 and get a 22.

Doesn't reciprocity assume similar antennas and similar
power levels? Of course, someone running the legal power
limit into a YAGI is going to be received well by almost
everyone but someone replying with QRP into a short
vertical whip is going to be at a disadvantage. Changes
in polarization in the ionosphere can easily explain the
above if one station is horizontally polarized and QSOing
with mobiles.
--
73, Cecil http://www.qsl.net/w5dxp


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"Cecil Moore" wrote in message
...
Buck wrote:
Many times I talk to the same
mobile in different locations. There are times I am received 59 and
hear 22. Other times I hear 59 and get a 22.

Doesn't reciprocity assume similar antennas and similar
power levels?

Even more important is accuracy of both "meters" and truth in reporting
Art



Of course, someone running the legal power
limit into a YAGI is going to be received well by almost
everyone but someone replying with QRP into a short
vertical whip is going to be at a disadvantage. Changes
in polarization in the ionosphere can easily explain the
above if one station is horizontally polarized and QSOing
with mobiles.
--
73, Cecil http://www.qsl.net/w5dxp


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And enter in the operator and their station

Alligator -- big mouth --- little ears

Elephant -- little mouth --- big ears

Excessive noise on one end of the circuit can be a problem also -- they
simply don't hear you thru the noise on their end, you hear them fine. No
contact.


--
Caveat Lector (Reader Beware)
Help The New Hams
Someone Helped You
Or did You Forget That ?



" wrote in message
news:35QQd.9987$4q6.2993@attbi_s01...

"Cecil Moore" wrote in message
...
Buck wrote:
Many times I talk to the same
mobile in different locations. There are times I am received 59 and
hear 22. Other times I hear 59 and get a 22.

Doesn't reciprocity assume similar antennas and similar
power levels?

Even more important is accuracy of both "meters" and truth in reporting
Art



Of course, someone running the legal power
limit into a YAGI is going to be received well by almost
everyone but someone replying with QRP into a short
vertical whip is going to be at a disadvantage. Changes
in polarization in the ionosphere can easily explain the
above if one station is horizontally polarized and QSOing
with mobiles.
--
73, Cecil http://www.qsl.net/w5dxp


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On Wed, 16 Feb 2005 22:48:31 GMT, "
wrote:


Even more important is accuracy of both "meters" and truth in reporting
Art

I know what you mean, but it wouldn't apply in this case. Unless a
meter were unstable. The mobile is sometimes the stronger of the two
and sometimes the weaker of the two. Often they are of similar
levels.

C Changes
Cin polarization in the ionosphere can easily explain the
Cabove if one station is horizontally polarized and QSOing
Cwith mobiles.

And, Cecil, would this not be true if both were of the same
polarization as well? If the polarization changes, it changes from
horizontal and would be vertical at the recipient's QTH.

Just a thought.


--
73 for now
Buck
N4PGW

Doesn't reciprocity assume similar antennas and similar
power levels?

Not both at once, I think.

The explanation I've seen of it is that if you have two radios having
identical transmitter power levels, then each radio's receiver will
"see" the same input voltage from its peer's signal even if the two
stations have wildly different antenna types (pattern, gain, takeoff
angle, polarization, etc.).

A change in one stations antenna which (e.g.) increases its gain in
the direction of the other, will increase both stations'
receiver-input voltage levels by the same amount... the changed
station "hears" the other station better, and also "speaks" better to
the other station by the same amount.

Naturally, the two stations may report different signal qualities
during the contact, depending on the sensitivities of their receivers,
on the local noise-floor level, on the presence of nearby in-band RFI
which desenses the receiver, on the meter calibration, on the
operator's hearing, on QSB which comes and goes at about the same rate
as the conversation changes directions, and so forth.

--
Dave Platt AE6EO
Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!