RADIO HABANA CUBA
The Broomstick Special: Part 1
A compact, easy-to-build shortwave antenna
BY ARNIE CORO
Host of "Dxers Unlimited"
SEND YOUR COMMENTS, QUESTIONS AND IDEAS DIRECTLY TO ME AT: firstname.lastname@example.org
Yes, this is a "helically wound" wire antenna. It can be built in a few hours... it will take longer if you really want to make it look pretty... UGLY versions can be assembled in minutes. It MAY be used without an antenna tuner, BUT... it works best when you do USE a TUNER.
Here are the easy-to-follow, step-by-step building instructions for Arnie Coro's "Broomstick Special:"
1. Obtain a nice broomstick.... you can use a "classic" wooden dowel broomstick, or substitute heavy walled PVC plumbers plastic tubing
2. Diameter of broomstick is not critical; anything from about 1.5 centimeters or better will work (this means that PVC tubing of about 19mm or 3/4 inch is ideal)
3. Prepare a base to hold the broomstick or PVC pipe vertical... Use a wide base, with enough counterweight attached to keep the broomstick vertical (I use mine next to the bedside radio, have convinced the wife that it is "modern art"
4. Obtain an aluminium disk of no less than 15 cm (6 inches) diameter. I prefer using a disk of around 30 centimeters (12 inches) but this is not critical. DO USE THE DISK... as it provides a capacity hat termination and helps reduce NOISE PICK UP
5. Obtain enough No.16 PVC plastic covered household wire; this is the ideal choice, but if you can't find it, then you may use No.16 or No.18 enamel covered copper wire (the one used for winding motors and transformers). If you can't find No.16 PVC covered wire, then your second best choice is No.18 "speaker wire"
6. Connect one end of the wire to the aluminium disk, and start winding a uniform coil using the "broostick" as the coil form. YOU WANT A NEAT JOB! Turns should fit tightly one next to the other... the "broomstick" will be filled with the wire forming the coil... When you arrive at the bottom end, make a termination> I use a long bolt with nuts and washers to which I tie the end of the wire, and another wire that goes to the antenna tuner. This wire that goes to the tuner can be from 1 meter to 3 meters long (from 3 to 10 feet) but DO KEEP IT AS SHORT AS POSSIBLE.
7. After the antenna is built, you may want to protect it with tightly wound PVC plastic tape over the wire. For EXTRA protection, you can paint the whole antenna with several coats of SPRAY ENAMEL...
8. The antenna works best near a WINDOW!!! Or better yet, you can install it in your balcony or garden... BUT DO KEEP THE CONNECTIONS TO THE TUNER SHORT
9. The antenna is RESONATED with your antenna tuner.... YOU MAY USE IT WITHOUT A TUNER but results are not going to be as good as when the antenna is connected to the receiver via a well-designed antenna tuner
10. YES... YOU MAY USE IT FOR TRANSMITTING.... BUT... according to recent medical research information, keep it as far away as possible from your body!!!
11. The helically wound "broomstick" is a lot of fun to experiment with... It works best when you provide a ground connection to the antenna tuner - receiver combination. One way of providing an "artificial ground" is to connect a length of wire of no less than 5 meters as a "counterpoise," that meaning that you can let the wire hang around the room's floor or garden. Using the "broomstick" with resonant radials turns it into an excellent amateur radio antenna for a specific band... For example with 4 radials cut for the 15 meter amateur band and a 4 feet high broomstick, (about 1.5 meters)
I can work a lot of stations on 21 mHz, something I do often to demonstrate to visitors what can be achieved with simple homebrew antennas, even when you don't have a lot of space.
12. QUESTIONS.... to: email@example.com
13. FOR THE TECHNICALLY MINDED... Click here for Part 2 of The Broomstick Antenna!
6 February, 1998
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