On Sat, 3 Jan 2004 10:35:51 -0600 (CST),
(Richard Harrison) wrote:

If the signal must take a great circle route over
the North Polar region, problems increase.

Hi Richard,

This is a S+N/N problem, not propagation. It is not like the magnetic
pole is sucking signals into the ground. What the pole IS attracting
is the ionic flow from the sun's emissions which create a plasma of
noise.

73's
Richard Clark, KB7QHC

This is a S+N/N problem, not propagation. It is not like the magnetic
pole is sucking signals into the ground. What the pole IS attracting
is the ionic flow from the sun's emissions which create a plasma of
noise.

73's
Richard Clark, KB7QHC



On 160 and 80 during disturbed conditions (aurora, etc.) signals are skewed by
as much as 90 deg from their short path directions. So it is not sucking but
blowing signals away from the disturbed region. Maybe sucking too, I haven't
been up there to see it. It is not just noise problem.
Some outrageous propagation stuff is in my old article at
http://members.aol.com/ve3bmv/bmvpropagation.htm

Yuri, K3BU, VE3BMV

Mark
I do believe that where the feed point is will make all the difference in
the world. A similar feed point up in the air but feeding colinear verticals
even tho they may be truncated will blow that thought away!
Regards
Art


"Mark Keith" wrote in message
om...
Richard Clark wrote in message

No doubt you were "prevented." They couldn't hear you!

I would tend to believe this account. Small vertical antennas next to
the ground with no radials, will be just a tad better than a dummy
load on that band. MK

Richard Clark wrote:
"The "earliest high frequency antennas" were in fact BCB."

Yes, but not in Ed Laport`s book. Ed`s book covers LF, MF, and HF. Ed as
Chief Engineer of RCA International was most interested in RCA`s
maritime service, radiograms, shortwave broadcast, and radio relay
services. These were conducted above 1700 KHz. Ed observes that HF
propagation is a statistical business, as the ionosphere is always in
flux. Ed gives guidance in using the NBS Central Radio Propagation Lab
publications, hardly the advice of someone stuck in low gear.

Ed gives some of the most complete information to be found on horizontal
rhombics and rhombic arrays, hardly the advice of someone treating the
use of low frequencies.

Richard Clark wrote: "And guess what, they (earliest high frequency
antennas) are still Vertical antennas.

I agree that 1.7 MHz is medium wave as the break is often chosen as
3MHz. I also agree that MW broadcasting antennas are universally
vertically polarized.

The primary service area of a MW broadcast station is defined by the FCC
as the area well served by the ground wave. Of course vertical polarized
antennas are used because horizontal polarization produces no ground
wave.

Art Unwin started this thread it seems because he faulted a vertical
antenna for not having a 100-mile range using low power.

The vertical has a null overhead almost guaranteeing no short-hop sky
wave.
Low power obviates ground wave DX.

To make an evening sky wave trip of 100 miles at 160 meters, Art needs
an antenna with a lot of high-angle radiation, 60 or 70-degrees more or
less to use the ionosphere for short skip, or he needs enough effective
power to punch a signal through along the ground.

A horizontal dipole could provide the high-angle radiation for the sky
wave.

A vertical antenna could provide the ground wave signal which only needs
enough power to work day or night.

A 1/4-wave vertical antenna can produce an unattenuated field strength
at the earth`s surface of about 195 mV/m at one mile. At 100 miles, the
field strength is 1%, or about 2 mV/m.. Depending on the soil
conductivity, the actual signal reaching a receiver at 100 miles is
likely much less than the unattenuated value. In a quiet location, not
much signal is needed.

Best regards, Richard Harrison, KB5WZI

On Sat, 3 Jan 2004 15:51:33 -0600 (CST),
(Richard Harrison) wrote:

Richard Clark wrote:
"The "earliest high frequency antennas" were in fact BCB."

Yes, but not in Ed Laport`s book. Ed`s book covers LF, MF, and HF. Ed as
Chief Engineer of RCA International was most interested in RCA`s
maritime service, radiograms, shortwave broadcast, and radio relay
services. These were conducted above 1700 KHz.

However, his observation was a historical one, not a current (at the
time of printing) one as evidenced by his stating that things changed.

snip
Art Unwin started this thread it seems because he faulted a vertical
antenna for not having a 100-mile range using low power.

The vertical has a null overhead almost guaranteeing no short-hop sky
wave.
Low power obviates ground wave DX.

This is far from true and again relies on HF, not MF observations.
You don't have to go very deep into your buddy's "Radio Propagation
Handbook" (Pete Saveskie). Chapter one, Ground Waves, employs a very
simple scenario with an 1/8th wave vertical radiator monitored out a
distance of 240 KM to no apparent difficulty in Ham terms, much less
FCC coverage issues. The discussion of the necessity for horizontal
antennas at this greater distance is notable by its vacuum in the
text.

My own study of Ground properties through a variety of references has
found there is quite a characteristic shift, a knee in the data, at
the 3 MHz frequency that clearly differentiates propagation at 160M
from that of 80M.

Shortwave stations clearly have an economic necessity to optimize
within their bands of operation. BCB stations are likewise
constrained. The two exhibit very different antenna solutions. It
follows that 160M more closely conforms to BCB than Shortwave for all
reasons considered.

To make an evening sky wave trip of 100 miles at 160 meters, Art needs
an antenna with a lot of high-angle radiation, 60 or 70-degrees more or
less to use the ionosphere for short skip, or he needs enough effective
power to punch a signal through along the ground.

A horizontal dipole could provide the high-angle radiation for the sky
wave.

And yet experience and reporting to this matter has shown abysmal
results. The shortfall of expectation with regard to actuality lies
in the Ground.

73's
Richard Clark, KB7QHC

Let me clarify this statement so that we are on the same page.
I was hearing several conversations going on the same frequency. Those
conversing obviously were oblivious to other users on the frequency because
of propergation or the peculiarities of my antenna.
I refrained from entering into conversation with the local group because by
joining one group would have caused problems for other groups on the same
frequency.
On reflection it would appear that the horizontal dipole gave low angle TOA
all the way thru 90 degrees.
Thus this is inferior to a vertical that captures the low angles and
descriminates against the high angles plus inferior to a poor vertical that
discriminates against low angles.
This just shows how much ground effect controls the
verticals but only to a much lower extent on horizontally polarised signals
with respect to selectivity.With respect to noise it does not affect me to
much in the comparison because of the use of a Faraday shield.
Regards
Art
"Art Unwin KB9MZ" wrote in message
m...
"Reg Edwards" wrote in message
...
Incoming radiation angles can be obtained by geometric calculation.
Pythagorus and all that, taking earth curvature, height of ionospheric
layers, number of hops, etc, etc, into account.


Then point your receiving beam into it, if it is adjustable in the
vertical
plane. Very non-critical. Antenna apperture angles in the vertical
plane
are extremely broad.


The stuff often comes in from more than one angle. Interference between
the
different paths causes fading and distortion. An antenna will collect
from
all vertical angles regardles of elevation.
----
Reg

===================



Interesting thing happened with the antenna last night.
Had the antenna in the vertical position close to ground ( it is a
truncated co linear dipole) And was prevented from joining the local
group because of multiple QSOs on the same frequency!

Art

" Art Unwin KB9MZ" wrote in message news:9LFJb.49578$I07.153955@attbi_s53...
Mark
I do believe that where the feed point is will make all the difference in
the world. A similar feed point up in the air but feeding colinear verticals
even tho they may be truncated will blow that thought away!
Regards
Art

I doubt it. I use fairly large antennas on that band and still don't
come close to many of the "big strappers" on that band. I've got a
full size inv L, about 45 ft vertical, and also a 42 ft top loaded
vertical. The top loading consists of four 60 ft wires.
Current up the vertical section is nearly constant on that antenna. I
bet that simple antenna will truncate your short collinear verticals
in any direction, and even it's nothing to really get excited about.
MK

" Art Unwin KB9MZ" wrote in message news:acKJb.51720$xX.290427@attbi_s02...
Let me clarify this statement so that we are on the same page.

On reflection it would appear that the horizontal dipole gave low angle TOA
all the way thru 90 degrees.

??? 90 degrees is straight up. NO low horizontal dipole will have very
good low angle performance on that band. Trust me. I used a full size
Z dipole for two years,"01-02" and ended up yanking it down. Good for
close in local stuff. Pitiful for lower angle far off stuff.

Thus this is inferior to a vertical that captures the low angles and
descriminates against the high angles plus inferior to a poor vertical that
discriminates against low angles.

How is it inferior? It's just different. You choose the antenna to
match the path you want to work. If you are going to talk 100-150
miles away, yes a low dipole will work pretty well, maybe the best.
But so will an inv L, or even my top loaded vertical will usually do
fine also. The L will usually be the better of the verticals close if
it's up and down sky wave, as it has more horizontal componant. My
loaded vertical has an overhead null.
Even still, many times, even just 200 miles away, my loaded vertical
is better than the L. Actually, the loaded vertical beats the L
probably 90% of the time. Even fairly close. Farther off paths? The
dipoles I had were poor at best. The vertical is the only way to go in
that case for a simple antenna. Remember, my dipole was at maybe 35-40
ft. Thats like a 80m dipole at 15-20 ft off the ground. Will be poor
for long distance use. Of course, using ground wave, the loaded
vertical is king of the hill here...

This just shows how much ground effect controls the
verticals but only to a much lower extent on horizontally polarised signals
with respect to selectivity.

??
With respect to noise it does not affect me to
much in the comparison because of the use of a Faraday shield.

?? Shield for what? You? MK

"Rick Karlquist N6RK" wrote in message news:bBDJb.48697$I07.144572@attbi_s53...
Here's my experience.

On transmit:

160 meters: 90 foot vertical is 20 dB better than 60 ft high inv vee
80 meters: 60 foot vertical is 10 dB better than 60 ft high inv vee
40 meters: 30 foot vertical is equal to 90 ft high inv vee

Sounds about right, but try the 90 ft dipole against a 1/4 wave ground
plane mounted say at 55-60 ft. "That makes the overall height
about the same.. I bet the vertical trounces the dipole.

20 meters: 30 foot vertical is beaten by 90 ft high inv vee about 25% of
the time
I usually prefer the dipole on this band...

15 meters and up: Any dipole trounces any vertical.

Have to disagree here though. I've had numerous 10m verticals that
beat any dipole I tried on most low angles...Same for 17m, when I used
an elevated 5/8 ground plane at 36 ft. Dogged all my other antennas.

On receive:

160 and 80 meters: A low dipole trounces any vertical

Not sure on this one...I assume you see this due to a better s/n ratio
with the dipole...Overall, I don't totally agree with this one
though...I think it's reciprical. Which ever transmits best, usually
receives best in what I see here.
I often receive using the vertical. But I don't have any fancy receive
antennas like beverages, or small phased verticals, etc..
40 meters and up: best receive antenna is best transmit antenna

I agree..Actually, I think this is really the case on any band, not
counting any s/n problems with a certain antenna on receive. I'm a
firm believer in reciprical operation. Only in a very few cases will
that not pan out. No matter what band I'm on, I usually transmit on
the antenna that receives the best. Very, very rarely is it not also
the best transmit antenna. MK

(Richard Harrison) wrote in message ...
Mark Keith wrote:
"For DX transmitting on the lower bands, vertical polarization is the
best way to go."

In some cases. If that were always the case, why do commercial shortwave
stations all use horizontal polarization for both point-to-point service
and broadcasting?

I don't know. I've wondered the same thing.

During my years in shortwave broadcasting, I never saw a single
vertically polarized antenna used for HF transmitting.

I believe you.

My experience is not unique. E.A. Laport was Chief Engineer, RCA
International Division of Radio Corporation of America (RCA). For many
years RCA was the largest short-wave communications organization in the
world. In his book, "Radio Antenna Engineering", Ed Laport says:

"The earliest high-frequency beam antennas used vertical polarization,
but subsequent evolution has caused the almost universal use of
horizontal polarization. There may be a reversion to vertical
polarization in the future for certain applications."

This seems to be more of a physical concern rather than which
polarization is actually the best over a certain path, for a certain
freq. There is no doubt in my mind vertical is almost always better
than horizontal for low freq's for long, low angle paths. Myself, I
think this applies all the way up to 40m or so.
My dipole on 40m was only 35-40 ft. Not a 1/2 wave up. But not once
did it ever beat my vertical long haul, or even semi long haul. It has
trouble beating my 10 ft tall vertical on my car. I tried this many
times from here to Fla. The mobile beat it every time we tried. And my
mobile is a low efficiency peanut whistle compared to the full size
elevated ground plane I ran on 40m. It's also nearly ground mounted.
MK