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2 Meter 1/4 Wave Ground Plane
 "RF Launcher"
By Dan, KE7TBB

Here is a very unique and one of a kind 2 Meter 1/4 wave ground plane project using the base of an Estes Model rocket launcher as a very portable support for 2 meter antenna fun. If you're into model rockets and have an old launcher base just sitting around and want to put it to work launching rf instead of rockets into the air, then read on.

The whole idea behind this project is to utilize that old model rocket launcher that is "just sitting on the pad" collecting dust, as a frame or support for a portable 2 meter ground plane antenna. Now it will be used to "launch" rf instead of rockets!

Parts you will need:
Estes model rocket launcher no. 302215 (You may use other brands and models using your own modifications).
Copper wire. About 57 inches or so depending on your construction
S0-239 connector (optional)
J B weld
Assorted tools:
soldering iron, solder
Nylon wire ties (Optional)

Start by assembling the launcher. When completed, remove the metal blast deflect plate and the small black plastic tube attached to it.
Remove one of the legs.
On the second opening of the leg insert the SO-239 connector.
JB weld or hot glue into place the SO-239 connector leaving room for the solder joints. Cut exactly 20 centimeters or 8 inches of wire. Strip and tin both ends of the wire.

Remove the metal rod from the launcher and solder the wire 2 centimeters or about an inch from the end of the rod. Insert the rod back on to the legs.
Wrap the wire around the leg with the SO-239 connector. Then solder the wire to the center of the SO-239 connector.

Now for the ground plane.
Start by cutting 3, 30 centimeter or foot long pieces of wire. Strip and tin one end only. Take one of the wires and cut it 12 centimeters or 5 inches from one end of the wire. Strip and tin both halves. Solder both ends to the outside of the SO-239 connector.
Bend the long wire towards the end of the foot and tape it or use nylon ties onto the foot. Bend the short wire towards the center of the launcher. Tape it there but leave the very end of the wire lose.
Solder the other 2 wires to the small wire and tape them down the other 2 legs.
Additional note: Vertical Radiator attaches to center of SO-239, radials to outer shell of SO-239.

Tuning: For tuning, shorten or lengthen the wire feeding the vertical rod or the rod itself as needed.

Tip: For ultimate portability do not solder the wire to the rod. Instead stick the rod and wire in the clamp together, that way you can take the rod out of the base. Also take the legs off the clamp and fold them together without breaking the wire. One more thing, the rod can come apart in 2 pieces if needed for modification.

Dan Nezgoda ~~~ KE7TBB

Editor's Note:
This project is a 1/4 wave 2 Meter ground plane using the rocket launcher as a support base for portability. Use your imagination and skills when building yours. Remember that this project is nothing more than a 1/4 wave ground plane for 2 meters and is not complicated, just tune the antenna lengths as you normally would with a "standard" ground plane antenna. Tune for lowest swr using very low power.

This is only one suggested method. You may discover other methods using a rocket launcher. You can eliminate the SO-239 and just attach the coax feed line at or near the base of the vertical section as with any 1/4 wave ground plane construction. The vertical section and the radials should be near 1/4 wave each as needed for best swr at your center frequency. EXPERIMENT and have fun launching RF on the 2 meter band! 73
Questions? Email Dan 


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