RC,

I use 3/4" Schedule 40 White PVC Pipe.
http://www.harvel.com/pipepvc-sch40-80-dim.asp
SIZE = 3/4" / OD = 1.050 / ID = 0.804
WT = 0.113 / Lbs/Ft = 0.226

It Works Like This :
The 2.75 Inch Slinky goes over the 1.05" PCV Pipe.

Hey - Just for Fun - Take the Pipe and slant it at an angle
place the Slinky at the Top-End over the Pipe and let it
slide down - - - Gee this is Fun ) !

UPDATING THE DESIGN : {ADDENDUM} PART II OF THE
SLINKY - Multi-Band "Off-Center" Vertical Dipole Antenna
for Shortwave Listening.
http://groups.yahoo.com/group/Shortw...a/message/6094

A 'second' build of this Off-Center-Fed Dipole Antenna
had me use a Ten Foot (120") piece of PVC Pipe to use
the Bottom 17 Inches as the Mounting Section. Plus a
way to Route the Coax Cable Feed-in-Line 'through' the
PVC Pipe vice having it hang on the outside of the Pipe.
So I added a 'new' 3/8" Hole in the PVC Pipe for the Leads
of the Matching Transformer to pass through.

Building the PVC Pipe Antenna Form :
The Ends of the 'cut' Slinky go through the Holes that you
Drill in the Pipe. Drill Four (4) 1/8" Holes through both
sides of the PVC Pipe :
Hole # 1 - One an 17 Inches from the Bottom
Hole # 2 - One 53 Inches from the Bottom
Hole # 3 - One 55 Inches from the Bottom
Hole # 4 - One 119 Inches from the Bottom (1" Top)
Align all Four (4) Holes up along the length of the Pipe.
Plus One 3/8" Hole aligned on One-Side-Only at 54 Inches
from the Bottom for the Feed-in-Line.

Note - Only put a PVC "Cap" on the Top End of this Ten Foot
piece of PVC Pipe to seal the Top from Weather.

Pre-Assembly :
The TV Matching Transformer is connected to the RG6 Quad
Shield Coax Cable. A Fish Line is then fed through the
3/8" Hole and down to the Bottom of the Pipe. The Leads
of the Matching Transformer are pulled up through the 3/8"
Hole.
Note - This places the Matching Transformer and the Coax Cable
Feed-in-Line inside {Hidden in] the PVC Pipe.

Making and Rigging the Antenna Elements :
The Slinky is 'cut' at Turn (Coil) # 36 and you have two
pieces of Slinky :
- One shorter piece with about 36 Turns.
Stretch this one between Holes #1 and #2; and Thread the
each of the Ends into the nearest Hole; then Bend the Tips
over to Secure Ends of the piece of Slinky.
- One longer piece with about 64 Turns
Stretch this one between Holes #3 and #4; and Thread the
each of the Ends into the nearest Hole; then Bend the Tips
over to Secure Ends of the piece of Slinky.

Making the Connection :
Connect the 300 Ohm Leads of the Matching Transformer to
the upper and lower Ends of the Slinky coming out of Holes
#2 and #3. Twist the Lead Wires around the Bent Ends of
the Slinky and Solder them to from a solid joint.

Weather Proofing the Antenna :
Seal all the Holes made in the PVC Pipe.
The Bottom can simply be 'plugged' with Foam.

Mounting the PVC Pipe :
Two Hose Clamps a Foot apart on top of a piece of Top-Rail
works great. One Inch up from the Bottom; Two Hose Clamps
about 12 Inches apart; with about 4 Inches between the Top
of the Top-Rail (Mast) and the Bottom Coil of the Slinky.
- Place the Top-Rail along side the House and secure it.
- Or stick a few feet of the Top-rail in the ground in
the Yard.
Another "Field-Day" Option is to use a 4'-6' Foot piece
of Re-Bar pounded half-way into the ground and then use
two Hose Clamps about a Foot apart to hold the PVC Pipe
bottom about a foot or two above the ground and securely
in an up-right position. (This should result in having
the Bottom Slinky Coil about 4"-6" above the Top of the
Re-bar.)

The Hook-Up to the Radio/Receiver :
* Radios with an 1/8" External Antenna Input Jack.
Use a 90* Elbow "F" Connector with an "F" Connector to
1/8" Mono Plug 'Adapter'.
* Receivers with an SO-239 External Antenna Input Jack.
Use an "F" Connector to PL-259 Plug 'Adapter'.

TIP - To make this 'Limited Space' Off-Center-Fed Verical
Dipole Antenna work better; try using an Active Pre-Selector
with it; between the Antenna and the Radio.

All of these Active {In-Door} Antennas can be used as a
"Pre-Selector" with good results with a 'short' External
Antenna mounted free and clear on the outside of the
House above the Roof or out in the yard.

* Ameco Tunable Pre-Amplifier Antenna (TPA)
http://www.universal-radio.com/catalog/sw_ant/1512.html

* MFJ-1020C In-Door Active Antenna
http://www.universal-radio.com/catalog/sw_ant/1413.html
- MFJ-959C Pre-Amplifier and Antenna Tuner
http://www.universal-radio.com/catal...amps/2574.html
- MFJ-1040C Active Pre-Selector
http://www.universal-radio.com/catal...amps/4110.html
- MFJ-1045C Receiver Pre-Selector
http://www.universal-radio.com/catal...amps/0807.html

* Palstar AA30 Portable Active Receiving Antenna
http://www.universal-radio.com/catalog/sw_ant/1492.html

* Vectronics AT-100 Portable Active Antenna
http://www.universal-radio.com/catalog/sw_ant/3059.html


that's all folks - iane ~ RHF