Art:

Here is a URL with a couple of photos of HF antennas with real reflectors. For more, do a search for FRD-10, FLR-9, and
Wullenweber. Just look at the photos; most of the text is, unfortunately, not very accurate. While I never knew the
German originators of the design during WW2, I did work with the engineer who developed the US version back in the 50s.
http://www.mindspring.com/~cummings7/wullen.html
--
Crazy George
Remove N O and S P A M imbedded in return address

i dont' know if i would really call them 'reflectors'. from the shape and
spacing i would think they were more of a vertical ground screen behind the
monopoles. kind of like having a dipole mounted above a ground screen, it
would provide some directionality outward and shield them from noise from
the building inside.

"Crazy George" wrote in message
...
Art:

Here is a URL with a couple of photos of HF antennas with real reflectors.
For more, do a search for FRD-10, FLR-9, and
Wullenweber. Just look at the photos; most of the text is, unfortunately,
not very accurate. While I never knew the
German originators of the design during WW2, I did work with the engineer
who developed the US version back in the 50s.
http://www.mindspring.com/~cummings7/wullen.html
--
Crazy George
Remove N O and S P A M imbedded in return address

Art Unwin wrote:
"So how does one "create" several conductive surfaces of what ever
length on a continuous electrical surface?"

First examine the ways it has already been done and ask why? A
non-resonant reflector provides a much wider bandwidth than a resonant
reflector as used in an array like a yagi, for one thing.

Plenty of grid-dish, corner-reflector and similar non-resonant reflector
antennas are in use to reduce wind-loading. You have no need at lower
frequencies to use solid reflectors. Surface irregularities are not much
problem. The solid dishes at 2-GHz are built that way for convenience,
not because they need to be. The same is true at lower frequencies. At
higher frequencies, the conductors are so close together, there isn`t
enough reduction in wind-loading to be worth the construction effort
required with grid-reflectors.

Grid reflectors only need a collection of conductors parallel with the
radiating element(s) illuminating (driving) the antenna, and placed for
best results. Reflecting elemants in a grid reflector placed
perpendicular to the driven element don`t work. Curvature is used tn
dish reflector bars for focus. An angle is used in the corner-reflector
for more gain than a flat reflector. None of the reflectors needs
cross-connections between the reflector bars anymore than ground radials
need their far-ends interconnected. Such connections allow eddy currents
which only cause loss. The only current of value is that in the
direction of the ground radials or in the direction of the reflector`s
parallel conductors, as the case may be. So the eddy currents are bad.

Spacing between reflector bars is related to wavelength and capture
area.. Measure it in a good grid antenna and scale to your frequency.
Or, see Kraus for capture area etc.

Best regards, Richard Harrison, KB5WZI

Crazy George`s information on the Wullenweber is great. I have no
information on this monster but a pair of loops or Adcock directional
antennas can be mounted perpendicularly and their outputs can be
connected with a goniometer to provide the effect of rotating the
directional antenna while the array remains unmoved in place. Terman
shows how on page 1051 of his 1955 edition. Could our military be
extravagant with taxpayer money?

Best regards, Richard Harrison, KB5WZI

Terman
shows how on page 1051 of his 1955 edition.

Not in 1947 edition:-(

73,
Chip N1IR

Chip, N1IR wrote:
"Not in 1947 edition (sad face)."

Too bad. Authors neeed new additions to new editions so owners will
upgrade.

Terman`s topic "Goniometer" starts on page 1050 of his 1955 edition.
His illustration is Fig. 26-29: "Crossed loop antennas connected to
goniometer."

Each loop`s feedline is connected to a fixed goniometer coil and these
are crossed at right angles. A rotating pickup coil is mounted inside
the fixed coils and shares their axis. The output to the radio is taken
from the goniometer`s rotating coil. Terman writes:
"Thus the rotation of the goniometer secondary is equivalent
electrically to rotating the loop (or Adcock) antenna."

In 1960, the chief of our Argentine oil exploration and production
called me into his office on Tierra del Fuego to ask me if Dr.
Maldonado, our physician, and not Alec Eussler, our atomic physicist
(aka radio technician) should be ordering the goniometer.
Our chief, George Blackwell thought the goniometer was diagnostic
equipment for a social disease.

Best regards, Richard Harrison, KB5WZI