On 07/03/15 09:34, Jeff wrote:

Since a vertical aerial that I described initially emits all three of
these waves, I was interested in the relative amounts of the RF power
supplied to the antenna that goes into each. For example, does the sky
wave component take 90% of the power, leaving 10% for the space and
surface waves? What phenomena control this?

You are missing the point Spike, the antenna has no knowledge of how the
power that it radiates will propagate. It all depends on how much power
leaves the antenna at what angle, and what angle the antenna is
positioned relative to ground.

All the antenna has is a polar response of how much power is radiated at
what angle. It is that angle and the way the atmosphere reacts at any
particular time that controls the propagation of waves. This can vary
with time of day etc.

What controls the polar diagram is the physical dimensions of the
antenna, the height above ground, the conductivity of the ground, the
proximity of other objects, and other factors.

Thanks for the comments, Jeff. Perhaps I'm not being clear enough.

Look at the issue this way.... While it's clear that the totality of the
e/m emissions from from the antenna depend on factors such as length,
height, and ground, (and I originally assumed a particular set-up in the
OP) there are three distinct methods by which such a transmission can be
received: the sky wave path to a distant receiver, a space wave to a
line-of-sight receiver (that could easily be outside the surface wave
range) and the surface wave to a receiver tucked into the far side of a
hill with no sky wave or space wave path. It can be expected that
increasing the transmit power will increase the received signal at all
three locations, but the question I'd like to see answered is: what
proportion of the power supplied to the antenna goes to each of these
three phenomena, which all arise every time the transmitter is keyed.
They might all be connected by the conditions you mention, I'm not
suggesting they aren't, but for the set-up I originally described, what
are the proportions of the power supplied to the antenna that contribute
to each?

Or, to put it in yet another way...There might only be one 'wave'
launched from the set-up, that propagates in three different 'modes'
(for the want of a better word); so what controls the relative
power/energy with which each 'mode' is propagated?

The case I'm particularly interested in is the short-rod vertical not
connected to ground, in the MF/low-HF bands, as might be found in a /M
set-up.


--
Spike

"Hard cases, it has frequently been observed, are apt to introduce bad
law". Judge Rolfe

On 3/7/2015 5:13 AM, Spike wrote:
On 07/03/15 09:34, Jeff wrote:

Since a vertical aerial that I described initially emits all three of
these waves, I was interested in the relative amounts of the RF power
supplied to the antenna that goes into each. For example, does the sky
wave component take 90% of the power, leaving 10% for the space and
surface waves? What phenomena control this?

The antenna emits only one wave. It is its environment that determines
the strength at any distant point.

You are missing the point Spike, the antenna has no knowledge of how the
power that it radiates will propagate. It all depends on how much power
leaves the antenna at what angle, and what angle the antenna is
positioned relative to ground.

All the antenna has is a polar response of how much power is radiated at
what angle. It is that angle and the way the atmosphere reacts at any
particular time that controls the propagation of waves. This can vary
with time of day etc.

What controls the polar diagram is the physical dimensions of the
antenna, the height above ground, the conductivity of the ground, the
proximity of other objects, and other factors.

Thanks for the comments, Jeff. Perhaps I'm not being clear enough.

That's because you have a misunderstanding of radiation through a medium.

Look at the issue this way.... While it's clear that the totality of the
e/m emissions from from the antenna depend on factors such as length,
height, and ground, (and I originally assumed a particular set-up in the
OP) there are three distinct methods by which such a transmission can be

They are not distinct. They merge and separate based on the environment
in which they exist.

received: the sky wave path to a distant receiver, a space wave to a
line-of-sight receiver (that could easily be outside the surface wave
range) and the surface wave to a receiver tucked into the far side of a
hill with no sky wave or space wave path. It can be expected that
increasing the transmit power will increase the received signal at all
three locations, but the question I'd like to see answered is: what
proportion of the power supplied to the antenna goes to each of these
three phenomena, which all arise every time the transmitter is keyed.
They might all be connected by the conditions you mention, I'm not
suggesting they aren't, but for the set-up I originally described, what
are the proportions of the power supplied to the antenna that contribute
to each?

Or, to put it in yet another way...There might only be one 'wave'
launched from the set-up, that propagates in three different 'modes'
(for the want of a better word); so what controls the relative
power/energy with which each 'mode' is propagated?

There are no 'modes'. The wave is affected by its environment. It is
impossible to know what the signal strength at a distant point without
knowing all the characteristics of the medium through which it passes.

The case I'm particularly interested in is the short-rod vertical not
connected to ground, in the MF/low-HF bands, as might be found in a /M
set-up.

What is a /M setup?

On Sat, 07 Mar 2015 08:18:00 -0600, John S wrote:

What is a /M setup?

Mobile as in M0WYM/M


Charlie.
M0WYM.



--
Hello Wisconsin!

"Spike" wrote in message
...
Thanks for the comments, Jeff. Perhaps I'm not being clear enough.

Look at the issue this way.... While it's clear that the totality of the
e/m emissions from from the antenna depend on factors such as length,
height, and ground, (and I originally assumed a particular set-up in the
OP) there are three distinct methods by which such a transmission can be
received: the sky wave path to a distant receiver, a space wave to a
line-of-sight receiver (that could easily be outside the surface wave
range) and the surface wave to a receiver tucked into the far side of a
hill with no sky wave or space wave path. It can be expected that
increasing the transmit power will increase the received signal at all
three locations, but the question I'd like to see answered is: what
proportion of the power supplied to the antenna goes to each of these
three phenomena, which all arise every time the transmitter is keyed. They
might all be connected by the conditions you mention, I'm not suggesting
they aren't, but for the set-up I originally described, what are the
proportions of the power supplied to the antenna that contribute to each?

Or, to put it in yet another way...There might only be one 'wave' launched
from the set-up, that propagates in three different 'modes' (for the want
of a better word); so what controls the relative power/energy with which
each 'mode' is propagated?


You have to get it in your head there is not 3 differant waves launched from
the antenna. There is only one wave. As it leaves the antenna, whatever
the wave hits determins if it is ground, sky or whatever. The patern of the
antenna determins how much goes where.

With some antennas the patern is such much of it goes out to the horizon and
not much up in the air. Others radiate much to the vertical and not much
toward the horizon.

Think of it as throwing a rock into the middle a small pond. If there is
noting in the pond, the wave will go out toward the edges equally. If that
same rockis thrown in near the edge of the pond, some of the ripples will n
hit th eedge of the pond near the rock first while it will take some time
for the ripples to hit the other side.
You have the same origional wave, but its propogation is modified as to
where it is at . You do not have seperate waves leaving the rock.

On 07/03/15 15:57, Ralph Mowery wrote:
"Spike" wrote

Or, to put it in yet another way...There might only be one 'wave' launched
from the set-up, that propagates in three different 'modes' (for the want
of a better word); so what controls the relative power/energy with which
each 'mode' is propagated?

You have to get it in your head there is not 3 differant waves launched from
the antenna. There is only one wave. As it leaves the antenna, whatever
the wave hits determins if it is ground, sky or whatever. The patern of the
antenna determins how much goes where.

With some antennas the patern is such much of it goes out to the horizon and
not much up in the air. Others radiate much to the vertical and not much
toward the horizon.

Think of it as throwing a rock into the middle a small pond. If there is
noting in the pond, the wave will go out toward the edges equally. If that
same rockis thrown in near the edge of the pond, some of the ripples will n
hit th eedge of the pond near the rock first while it will take some time
for the ripples to hit the other side.
You have the same origional wave, but its propogation is modified as to
where it is at . You do not have seperate waves leaving the rock.

Thanks for the explanation and illustration.

Amateur (and professional) literature abounds with terms like sky wave,
space wave, and surface wave. There are sky wave radars, space wave
radars, and surface wave radars, for example. It isn't unreasonable to
use these as descriptors of what I was trying to find out. This was, to
recap, the relative proportions of the RF power delivered to the aerial
for each of these (whatever one wants to call them), for a typical /M
(mobile) set-up on the MF and low HF bands operating over ground of
average conductivity, a near everyday occurrence in the Amateur
community. The mechanism for the single wave that's transmitted
resulting in (whatever one wants to call them) isn't really of interest,
but the relative proportions that wind up in (whatever one wants to
call them) are.

In terms of your analogy, the rock being thrown into the pool close to
one edge of the pond is the equivalent of the short rod /M aerial
operating close to the ground, mounted on the vehicle. I can imagine
that if the edge of the pond is a gentle sandy slope, the reflected
waves will be different in nature that if the edge of the pond is a
vertical rock. However, this is merely reflecting the different ground
conductivities that might be experienced in the real-life Amateur
situation: some energy will go skywards to a distant receiver, some will
travel through air to a line-of-sight receiver, and some will go to a
receiver in the shadow of a hill that cannot receive either of the other
two (whatever one wants to call them).

--
Spike

"Hard cases, it has frequently been observed, are apt to introduce bad
law". Judge Rolfe

On 08/03/15 09:33, Jeff wrote:
Spike wrote

I think you are coming at this from the wrong view point.

Perhaps the question that you should be asking is what take-off angles
are required to produce maximum ground wave, and how do you maximize
that for a MF mobile installation.

I'm really after figures for the proportions of the RF power fed to that
antenna, that finish up in whatever 'they' are called (the use of the
well-known word 'waves' seem to upset people despite their having been
used for the specifics I mentioned, for about 100 years).

I'm aware that reconfiguring the set-up might affect these proportions,
but I did refer the original query to a typical /M (mobile) set-up of a
short rod antenna not connected to ground and operating over average
conductivity in the MF/low-HF bands.

For example, does 40% power the sky (redacted), another 40% power the
space (redacted), and the other 20% power the surface (redacted)?
Clearly, 100% of the RF power goes somewhere, and the various parts of
it must add up to 100% - so what are the proportions?

If the /M (mobile) set-up was changed to a /P (portable) one with a 5/8
lambda ground-mounted antenna, the sky (redacted) proportion would lower
and the surface/space (redacted) would increase - but from what to what?

I'm beginning to think that this topic is either so simple or so complex
that most Amateurs have either forgotten it or have never heard of it.

--
Spike

"Hard cases, it has frequently been observed, are apt to introduce bad
law". Judge Rolfe

Spike wrote:

On 08/03/15 09:33, Jeff wrote:
Spike wrote

I think you are coming at this from the wrong view point.

Perhaps the question that you should be asking is what take-off angles
are required to produce maximum ground wave, and how do you maximize
that for a MF mobile installation.

I'm really after figures for the proportions of the RF power fed to that
antenna, that finish up in whatever 'they' are called (the use of the
well-known word 'waves' seem to upset people despite their having been
used for the specifics I mentioned, for about 100 years).

I'm aware that reconfiguring the set-up might affect these proportions,
but I did refer the original query to a typical /M (mobile) set-up of a
short rod antenna not connected to ground and operating over average
conductivity in the MF/low-HF bands.

For example, does 40% power the sky (redacted), another 40% power the
space (redacted), and the other 20% power the surface (redacted)?
Clearly, 100% of the RF power goes somewhere, and the various parts of
it must add up to 100% - so what are the proportions?

If the /M (mobile) set-up was changed to a /P (portable) one with a 5/8
lambda ground-mounted antenna, the sky (redacted) proportion would lower
and the surface/space (redacted) would increase - but from what to what?

I'm beginning to think that this topic is either so simple or so complex
that most Amateurs have either forgotten it or have never heard of it.

I suspect that the sort of precision with which one can measure signal
strength. plus very local variations of surface wave intensity due to
varying ground conditions, mean that it would be hard to know if the
signal level resulted from, say, one, five or fifty percent of the
transmitted power. So I suspect your question has never been answered.
An opportunity for some collaborative research between local amateurs?


--
Roger Hayter

On 08/03/15 12:24, Roger Hayter wrote:

I suspect that the sort of precision with which one can measure signal
strength. plus very local variations of surface wave intensity due to
varying ground conditions, mean that it would be hard to know if the
signal level resulted from, say, one, five or fifty percent of the
transmitted power.

So I suspect your question has never been answered.

But somebody must have done the research, somewhere...

An opportunity for some collaborative research between local amateurs?

No-one wants to run verticals...too difficult....

A 160m vertical aerial feeding a webSDR, located somewhere near the
centre of England, would, using surface (redacted) have a
fair-to-considerable percentage coverage of the UK Amateur population
and be very useful as a test-bed. Sadly, I don't live near Coventry,
although I've been sent there once or twice. The usual webSDRs seem to
run on horizontals, unsurprisingly, so not a lot of use for this sort of
thing.

--
Spike

"Hard cases, it has frequently been observed, are apt to introduce bad
law". Judge Rolfe

Spike wrote:
On 08/03/15 12:24, Roger Hayter wrote:

I suspect that the sort of precision with which one can measure signal
strength. plus very local variations of surface wave intensity due to
varying ground conditions, mean that it would be hard to know if the
signal level resulted from, say, one, five or fifty percent of the
transmitted power.

So I suspect your question has never been answered.

But somebody must have done the research, somewhere...

Thoroughly researched for well over 100 years but you refuse to read
the research which says your question in the form it is being asked
is meaningless.

An opportunity for some collaborative research between local amateurs?

No-one wants to run verticals...too difficult....

Vertical antennas have little to nothing to do with the essence of
your question.


--
Jim Pennino

Roger Hayter wrote:

snip

I suspect that the sort of precision with which one can measure signal
strength. plus very local variations of surface wave intensity due to
varying ground conditions, mean that it would be hard to know if the
signal level resulted from, say, one, five or fifty percent of the
transmitted power. So I suspect your question has never been answered.
An opportunity for some collaborative research between local amateurs?

The answer would apply only to one specific antenna at one specfic
frequency at one specific location at one specific point in time.

The biggest variable in all this is at one point in time.

The general approximate answer is:

To maximize skywave propagation the antenna main lobe should have an
elevation angle of around 20 to 30 degrees and the frequency has to
be less than the maximum frequency the ionosphere is currently capable
of reflecting.

To maximize line of site propagation the antenna main lobe should have an
elevation angle as close to zero as possible assuming both ends of the
communication are on the Earth.

To maximize surface wave propagation the antenna main lobe should have an
elevation angle as close to zero as possible and the frequency should be
less than 3 MHz.



--
Jim Pennino