On Fri, 2 Jan 2004 23:58:37 -0600 (CST),
(Richard Harrison) wrote:

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?

Again this HF advice to an MF enquiry. The two, propagationally are
as different as bananas and apples.

In his book, "Radio Antenna Engineering", Ed Laport says:

"The earliest high-frequency beam antennas used vertical polarization,

This begs the historical perspective that the meaning of High
Frequency has not been constant. Laport's statement belies this era
he quotes who characterized High Frequency as anything above 500 KHz
and often characterized the shortwave frequencies as Ultra High
Frequencies.

The "earliest high frequency antennas" were in fact BCB. And guess
what, they are still Vertical antennas!

but subsequent evolution has caused the almost universal use of
horizontal polarization.

The subsequent evolution is explicitly shortwave. This validates your
experience but says nothing of the problem at hand in the 160M band,
which by example of a few KHz away is dominated by BCB verticals
almost to the point of saturation.



73's
Richard Clark, KB7QHC

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

(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

Mark Keith wrote:
"My dipole on 40m was only 35-40 ft. Not 1/2-wave up. But not once did
it ever beat my vertical long haul."

I believe Mark. The scales may be tilted in the favor of Mark`s vertical
by the high-conductivity soil at Mark`s QTH.

Commercial stations spend what it takes to put those horizontal antennas
up at elevations which bring the take-off angle down low enough to reach
out the distance to the target area.

At high elevation, a dipole becomes bidirectional in azimuth. This gain
is often enhanced by a reflector, directors, extended element lengths,
or additional in-phase elements. Curtain arrays are popular transmitting
antennas. So are rhombics, especially for point-to-point, for both
transmission and reception.

Receiving antenna farms rely on rhombics, Beverages, fishbones, etc,
where the object is directivity and gain to give S/N, if not efficiency.

Best regards, Richard Harrison, KB5WZI

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

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

"Art Unwin KB9MZ" wrote in message
m...
Looking for a site or information on incoming
radiation angles specifically for 160 metres.

1 How is it measured ?
1a Can it discriminate between vertical and horizontal
or what ever polarisation

2 What is the angles per percentage of contacts

3 Are they all horizontally polarised when subject to skip?
for distances over say 1000 miles distance

One well known DXer (Tom) stated on this
newsgroup that a horizontal dipole at 1/2 wave
length was inferior to his other antennas, but
no specifics given!

Appreciate any pointers on the above.
Happy New Year
Art

"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, KB9MZ wrote:
"And was prevented from joining the local group because of nultiple QSOs
on the same frequency."

Single-element vertical antennas are deficient in directivity at any
azimuth. They have a single null off their tips, that is toward the
zenith.

At HF, groundwave disappears with increasing frequency. Thus, short
range communication is hindered.

Best regards, Richard Harrison, KB5WZI

On 1 Jan 2004 05:57:04 -0800, (Art Unwin KB9MZ)
wrote:

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

Hi Art,

I'v noted a lot of HF advice to your MF question. Most of it of the
quality of looking under the street lamp for lost keys because that is
where the light is.

No doubt you were "prevented." They couldn't hear you! How is it
your heard them? You used the same polarization they were
transmitting in. Now, these are two significant clues to your
problem(s).

Elsewhere you've offered:
Well I have put my dipole in the vertical position also which negates use of
radials but I have not noticed any profound differences as yet after a few
days !
Another clue (really the same as the two above) which reveals the
problem of so quickly embracing the presumed proof of this "negation."
You negated nothing but opportunity. Your claim is identical to those
CFA's "FCC tested" in Georgia that are 20dB down from their reference.
Your vertical dipole misses only the phasing circuit to qualify for
the Nomenclature gain.

73's
Richard Clark, KB7QHC

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

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