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http://home.comcast.net/~kb7qhc/ante.../Cage/cage.htm

http://www2.arrl.org/news/stories/2001/05/03/2/

http://www.pust-norden.de/oloog/oloog-2_gr.jpg

http://www.qsl.net/wa2tvs/antennas/archive17.htm

http://www.antenna.be/tel-ave0640.html


iane ~ RHF
..
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Goal:
* Minimum fuss 3-30MHz operation, mostly on 5-15MHz.
* Will use step-dowm RF transformer between antenna and low impedance
coax
* May use autotuner on TX
* Like the wirecage antennas still today seen on many a military
vessel.

Available on roof:
- 25ft steel structure (like piramid base for power line)
- about 100 feet space in one direction
-...to abandoned flue chimney, 100ft away and 10 feet lower than base
of steel structure
- roof covered with alu plates on tar (could be all arc welded
together, perhaps.

THIS LOOKS PRETTY MUCH LIKE A SHIP TO ME cept its' 120ft aboveground.

I want to build a wire cage monopole
- sloping down from steel tower
- using tower as counterpoise
- feedpoint at top of sloper, via stepdown rf transfomrer, grounded to
tower
- coax cable lead, with rf choke coils and surge suppressors.

Questions:
- what kind of cage antenna?
- how many wires?
- what spreaders, how large?
- ideal wire?

Current plan config:
- length 14 m = 2 x 4m straight sections, + 2 x 3m truncated cubes
- spreaders at 3-7-11 m
- 140 cm dia. spreaders, each made with two waterproofed bamboo
triangles in "star of David" configuration; wire kept parallel at 70cm
distance from each orther.
- material: .8mm copperclad, abt. 90 m (270 ft) total.

Any hints, like more/fewer parallel wires, broader / smaller
spreaders, different materials, dirrerent antenna wire, RF
downtransformer, whatever?

Filippo

Thank you all again for the deluge of tips & links!
This is getting seriously fun!

Quick update on my trials with copperclad (maybe just copperflashed)
metal-inert-gas continuous welding steelwi

- This stuff solders like heaven! Steel disperses heat less than
copper, and capillarity is amazing. Hot solder joints catch deep
between twisted wires.

- Steel is quite springy and retains shape. My spool is small (~5"
dia.) but if I release the wire it falls into 15" loops.

- I made a 20' dia. loop with 3+ rounds of this wire, and soldered it
at 6 spots all round. Very light and elastic.

You know where I'm heading. I would like to try a lightweight soldered
all-steel cage, and rustproof it with one of those steel-blackening
nitric acid paints.

As a trial, I'd do a short cage with two 20" rings, maybe 2' between
them, and 3' end cones, paint it all, and hang it out in the elements,
weight-loaded.

The INEVITABLE QUESTION
=== Do cage spreaders HAVE to be insulating? ===

Uneducated guess: as VHF/UHF discones are made out of either radials
or sheet metal, I'd say that shorting spacers should be OK.

SL,

For a Cage Antenna 'using' Metal (conductive) "Spacers" for VHF and
UHF just may work.

But... Everything I have seen for HF (MW/SW) has non-conductive
spacers.
- - - wood, plastic, tie-off-ropes, etc.

* * * Here is an alternative idea:
Three-Five small 24" Hula-Hoops with 8-12 holes drilled into them for
the copperclad wire. Would be a quick and easy trial (proto-type)
model.
- Three to Five Feet (3Ft-5Ft) Top and Bottom "Cones".
- - Three to Five Feet (3Ft-5Ft) "Space" between the Hula-Hoops.
- - - Eight to Twelve (8-12) Wires 12Ft-30Ft Long.
- - - - Vertically Mounted with a Bottom Feed Point.

Note: Flexiable 1/2", 3/4" or 1" Black PVC Tubing that is designed
for Garden Watering Systems. Could be used for smaller circular
"Spacer" Loops. Form them to size and use a Wood Plug and Stapes to
join the ends. Then Drill the holes for the wires.

TIP: Simple Practial Considerations
- - - The "Rule-of-Thumb" in dealing with Mechanical Realities )

* Divide the Diameter of the Loops by Two(2) to 'determine' the
maximum "Number" of Wires that will fit around the perimeter of the
Loop.

* Multiply the Diameter by Five(5) to determine the appropriate
"Space" between the Loops.

EXAMPLES:
6" Loop = Three(3) Wires and Two Foot Spacing between the Loops.
8" Loop = Four(4) Wires and Three Foot Spacing between the Loops.
12" Loop = Six(6) Wires and Five Foot Spacing between the Loops.
16" Loop = Eight(8) Wires and Seven Foot Spacing between the Loops.
18" Loop = Nine(9) Wires and Eight Foot Spacing between the Loops.
20" Loop = Ten(6) Wires and Nine Foot Spacing between the Loops.
24" Loop = Twelve(12) Wires and Ten Foot Spacing between the Loops.


iane ~ RHF
..
..
OBTW: Visit the "SWL Antennas and AM & FM Antennas" which is
"Open-To-All" to Read and Post at YAHOO! eGroups.
GoTo= http://groups.yahoo.com/group/SWL-AM-FM-Antenna/
- - - This is my Antenna ~Golbewym~ [My Web Log].
..
..
= = (SpamLover)
= = = wrote in message . com...
Thank you all again for the deluge of tips & links!
This is getting seriously fun!

Quick update on my trials with copperclad (maybe just copperflashed)
metal-inert-gas continuous welding steelwi

- This stuff solders like heaven! Steel disperses heat less than
copper, and capillarity is amazing. Hot solder joints catch deep
between twisted wires.

- Steel is quite springy and retains shape. My spool is small (~5"
dia.) but if I release the wire it falls into 15" loops.

- I made a 20' dia. loop with 3+ rounds of this wire, and soldered it
at 6 spots all round. Very light and elastic.

You know where I'm heading. I would like to try a lightweight soldered
all-steel cage, and rustproof it with one of those steel-blackening
nitric acid paints.

As a trial, I'd do a short cage with two 20" rings, maybe 2' between
them, and 3' end cones, paint it all, and hang it out in the elements,
weight-loaded.

The INEVITABLE QUESTION
=== Do cage spreaders HAVE to be insulating? ===

Uneducated guess: as VHF/UHF discones are made out of either radials
or sheet metal, I'd say that shorting spacers should be OK.