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

On 08/03/15 14:22, Ralph Mowery wrote:

I think that Jeff may be on to something. What you need to do is download
one of the antenna modeling programs. Set it up for the antenna type you
want. Then you can look at the patten and see the take off angle. The take
off angle is what determins the ammount of power you have the differant
types of propogation.

That's an interesting thought, and one that had crossed my mind.
However, modelling is only as good as the modeller, and if things are
set up to model only the sky-wave component, I might not get the sort of
information I'm looking for. BICBW, as I've no experience of this.

However, I've just recalled that while researching the topic some time
ago, I came across some polar diagrams for cross-field antenna trials in
Egypt, which showed the ground/surface wave components as well as the
sky wave, the idea being for the MF broadcast band to maximise the
former and minimise that latter. Sadly, I didn't keep the url, but it
looks like it might be possible to determine some measure of the
relative power/field strengths. I'll see if I can find those diagrams,
the model used might have been mentioned.


--
Spike

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

"Spike" wrote in message
...
However, I've just recalled that while researching the topic some time
ago, I came across some polar diagrams for cross-field antenna trials in
Egypt,

Take them with a pinch of salt for the trials were discredited because they
were conducted withing the near field of a broadcasting mast, ISTR

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).

Yes, there is wide use of the word "waves", but not as you are using it.

To answer your question, all you have to know is the frequency, antenna
pattern, the current state of the ionosphere, ground conductivity,
terrain roughness and the dielectric constant in the area in question.

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.

Well, to start with, you get little to no surface wave propagation
above about 3 MHz.

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?

Once again, all you have to know is the frequency, antenna pattern,
the current state of the ionosphere, ground conductivity, terrain
roughness and the dielectric constant in the area in question.

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.

No, you simply do not understand how propagation works.

First read all of this:

http://en.wikipedia.org/wiki/Radio_propagation

Read the section on Modes very carefully.

Follow the links under Modes and read them:

http://en.wikipedia.org/wiki/Surface_wave
http://en.wikipedia.org/wiki/Skywave
http://en.wikipedia.org/wiki/Line-of-sight_propagation
http://en.wikipedia.org/wiki/Sporadic_E_propagation
http://en.wikipedia.org/wiki/Tropospheric_propagation



--
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

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

Spike wrote:
On 08/03/15 14:22, Ralph Mowery wrote:

I think that Jeff may be on to something. What you need to do is download
one of the antenna modeling programs. Set it up for the antenna type you
want. Then you can look at the patten and see the take off angle. The take
off angle is what determins the ammount of power you have the differant
types of propogation.

That's an interesting thought, and one that had crossed my mind.
However, modelling is only as good as the modeller, and if things are
set up to model only the sky-wave component, I might not get the sort of
information I'm looking for. BICBW, as I've no experience of this.

It is obvious you have no experience.

Antenna modeling programs DO NOT MODEL PROPAGATION.

Antennas have little to no direct relationship to propagation modes other
than putting a main lobe where some particular propagation mode may or
may not exist at some particular frequency at some particular point in
time.


--
Jim Pennino

On Sunday, March 8, 2015 at 3:40:21 AM UTC-5, Spike wrote:
On 08/03/15 00:17, wrote:

True ground wave, which to me, is the same as the surface wave,
actually can follow the curvature of the earth, which a space wave
cannot do. But true ground or surface waves are generally only
taken advantage of on the lower frequencies such as MW, or LW.

That's true, which is a shame as useful ground-wave/surface wave can be
had on 28 MHz; a maximum range figure for a path over ground of average
conductivity might be 25 miles, and considerably more if the path is
over water (especially sea-water).

That's space wave on 10m. Even seeing a surface wave on 40m is a bit
of a stretch from the norm. As I mentioned in my 2nd post, the reason
I saw farther than expected from space wave operation on 40m, could
well have been due to refraction of the space wave, and due to the fact
that the radio horizon is farther than the visual horizon.

I used to work local 10m all the time back in the 80's, early 90's..
25 miles is fairly easy with any decent antenna, at a decent height
above ground. I used to work a good bit farther than that fairly often,
when using an antenna at 35-45 feet up.



The reason I think so, is because the distances I could work with it
were a good bit farther than what I would expect with the space wave
alone.

Maximum surface wave over ground with average conductivity might be 40
to 45 miles on 40m; if you were getting ranges over this, then your
ground conductivity might have been enhanced, or due to the height of
your ground-plane, you could have experienced refraction of the space
wave. If your location was on a hill-top or other high ground, this
could have helped the space wave refraction as well.

The ground is good here, and the ground plane was full size at 36 ft
at the base of the antenna. But it may well have been an enhanced space
wave. I was often working well over 100 miles away in such a case.




I believe that the availability 24/7/365 of the space-wave and
surface-wave is one of Amateur Radio's undervalued assets. On 160m the
surface wave might reach over 100 miles, including behind hills and into
valleys, which here in the UK would enable a station to reach a
significant proportion of the UK Amateur population. Unfortunately,
people dismiss verticals in favour of horizontals of one form or
another, the usefulness of which drops to zero when the sky wave
disappears (apart from any vertically-polarized radiation from a
mismatched feeder or unbalanced elements).

Well, not everyone does. I know many on 160m who favor verticals.
Not only for ground wave, but better DX.
The ground wave is pretty good on 160m if using a vertical.
Nearly as good as on the MW AM broadcast band, being the two bands
are right next door to each other, so to speak.

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.

Spike, you're a gormless ****. Seriously, you're giving Gareth Alun Evans
G4SDW a run for his money here.

--
STC // M0TEY // twitter.com/ukradioamateur

On Sun, 08 Mar 2015 10:56:58 +0000, Spike wrote:


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).

You're digging a deep hole here, Burt. Perhaps it would be better for you
to KYGS?