On Mar 6, 4:12 pm, "James" no wrote:
Subject Was : Good outdoor omni-directional fm antenna ?
http://groups.google.com/group/rec.r...b62830262cf871
-
- Who makes a good outdoor, omni-directional fm antenna ?
-
- I prefer to use RG6 as the lead in, and I definitely need
- an omni-directional antenna.
-
- Radio Shack used to make a dual element, folded dipole
- outside fm antenna, but I don't find it on their website.
-
- Thanks for any tips !!
-
- James

James,

"Snake" [Mono-Pole] Vertical Antenna for the FM Radio Band

One of the simplist and cheapest Omni-Directional FM Antennas
that you can make yourself is a 5/8 Wave-Lenght Vertical Antenna.

The 5/8-Wavelength Mystique -by- L. B. Cebik [W4RNL]
http://www.cebik.com/gp/58.html

Vertical Antenna Calculator
http://www.csgnetwork.com/antennaevcalc.html
CopyRight© 1973-2008 - CSGNetwork.Com - All Rights Reserved.

Wave-Length (WL) ~ Feet
- - 1/4 WL ~ 2 Feet. 7 - 15/16 Inches -or- 0.810 Metres
- 1/2 WL ~ 5 Feet. 3 - 27/32 Inches -or- 1.621 Metres
* 5/8 WL ~ 6 Feet. 7 - 25/32 Inches -or- 2.026 Metres *
+ 3/4 WL ~ 7 Feet. 11 - 3/4 Inches -or- 2.431 Metres
Full WL ~ 10 Feet. 7 - 21/32 Inches -or- 3.242 Metres

What makes this Antenna Simple and Cheap is that it
is make of a Single Piece of Coax Cable.
-ps- It's a "Snake" [Mono-Pole] Vertical Antenna for the
FM Radio Band.

Start by taking a 25~ 50 Foot piece of RG-6 Quad-Shield
Coax Cable with "F" Connectors on both ends.

25-Ft. RG-6 QuadShield Coax Cable (Black) # 15-1567
http://www.radioshack.com/product/in...ductId=2103071
50-Ft. RG-6 QuadShield Coax Cable (Black) # 15-1568
http://www.radioshack.com/product/in...ductId=2103072

Cut off one of the "F" Connectors from one of the ends.
This is now the Antenna-End of your "Snake" [Mono-Pole]
Vertical Antenna.

FWIW - The End of the Coax Cable with the "F" Connector
still attached is the Radio-End of your "Snake" [Mono-Pole]
Vertical Antenna.

Measure 8 Feet along the Coax Cable from this Antenna-End
and place a Plastic Wire Tie around the Coax Cable to mark
the spot. This is your Zero-Point for Measuring.

Black UV Cable Tie Assortment (75-Pack)
http://www.radioshack.com/product/in...ductId=2103326

Very Carefully {Very Carefully worth repeating} slowly Cut
around the Outer Insulation of the Coax Cable on the
Antenna-End side of the Zero-Point. Then make a 6~8 Inch
lengthwise Cut through the Outer Insulation along the Coax
Cable toward the Antenna-End.

Carefully Peel-Back the Outer Insulation from the Shield
Braid and exposing the Braid; and Secure it temporarily
with Black Electrical Tape.

Very Carefully {Very Carefully worth repeating} slowly Cut
through the all four layers of the Braid and Foil Shielding
and exposing the Inner Insulation for several inches.

NOTE - When I refer to Inner Insulation : I am also referring
to the Center {Inner} Wire Conductor inclosed within it.

Again Very Carefully and slowly make a lengthwise Cut
through the Outer Insulation and along the Coax Cable
all the way to the Antenna-End; and Remove the Outer
Insulation.

Again Very Carefully and slowly remove all four layers
of the Braid and Foil Shielding one at a time; all the
way to the Antenna-End; exposing the Inner Insulation.

Return to the Zero-Point where you place the Plastic
Wire Tie to mark the 8 Foot Point. Measure from it
79 - 3/4 Inches* from it toward the Antenna-End.
* 5/8 WL ~ 6 Feet. 7 - 25/32 Inches (79 & 3/4 Inches)
Take a Felt-Tip Marker and mark this point on the Inner
Insulation. There should be about 4 Inches of Inner
Insulation left-over. Fold this Inner Insulation back
over on to and parallel to itself; measure about One
Inch from the Bend and place a Plastic Wire Tie at
that spot; The place two more Plastic Wire Tie back
down the two parallel Inner Insulations about each
Inch. Now att the Bend in the Inner Insualtion spread
open the two Inner Insulations to from an End-Eye "O".
This is your True Antenna-End and the Rigging Point
attachment for the top of your Antenna.

Next return to the Zero-Point where you place the
Plastic Wire Tie to mark the 8 Foot Point. Measure
toward the Radio-End 32 Inches* and a Plastic Wire
Tie at this Point. Affix a Snap-On Ferrite Core Bead
on the Radio-End side of the Coax Cable; next to
the Plastic Wire Tie; and then place another Plastic
Wire Tie on the 'other' side of it to Secure it in place.
* 1/4 WL ~ 2 Feet. 7 - 15/16 Inches (32 Inches)

Snap-Together Ferrite Choke Core # 273-105
http://www.radioshack.com/product/in...ductId=2103222

Return to the Zero-Point where you place the Plastic
Wire Tie to mark the 8 Foot Point. Place two more
Plastic Wire Ties around the Un-cut Outer Insutlation
about a 1/4 Inch apart. Cover the 3 of them from top
to bottom in Coax Seal plus a Half-an-Inch on either side.

Coax-Seal
http://www.universal-radio.com/catalog/cable/1194.html
Non-Conductive & Non-Contaminating Waterproof Sealant
for Out-Door Antenna Connections and/or Connectors.

RIGGING - MOUNTING :
Use Nylon/Poly Rope to Rig this "Snake" [Mono-Pole]
Vertical Antenna for the FM Radio Band by the End-Eye.
From an House Eave or Tree Limb. Idealy the Top-End
of this Antenna would be at least 16 Feet above the
the surface of the ground; higher would be better.

That-Something-Extra - This can be a good "Portable"
Camping FM Antenna; and it can be Rigged as a Sloper
Antenna at 45 Degrees with the Bottom pointed in the
direction of best/desired FM Radio reception.

TIP - For On-the-Roof / Above/Over the House Mounting
use a 10 foot Piece of 1/2 Inch PVC Pipe as an "Form"
for the Wire Antenna Element. Measure and cut the PVC
Pipe to 9 Foot 5 Inches (113 Inches). Drill a 1/8 Inch Hole
about One Inch from one of the ends of the PVC Pipe.
The Hole end is now the Top-End of the "Form". Thread
the Wire Antenna Element into the center of the PVC Pipe.
Align the End-Eye with the Hole in the PVC Pipe; and
place a small 1/8 Inch Metal Machine Screw through the
Hole and the End-Eye; capturing the End-Eye with the
Machine Screw; and place a Self Locking Nut on the
threaded-end of the Machine Screw. Glue an End-Cap
on the Top-End of the PVC Pipe and cover the Machine
Screw Head and Nut with Glue too. Use two to three
Large Hose Clamps or a half-dozen Plastic Wire Ties to
Secure the Bottom of the PVC Pipe to a Vent Pipe or
something else coming out of the Roof.

Finally connect the "F" Connector to yoyr FM Radio's
External Antrenna Input. { What Could Be Easier ! }