Ralph Moulton KA5RUZ lived in Norman, Oklahoma and he reworked the designs of an EH antenna. This page documents his plans for 10-meter, 20-meter, and 40-meter EH antennas.
This is a picture of Ralph in his garage shack. Two things stand out about this picture, the first is that all of the gear shown here was hooked up and operational. The second is that you can see two of his RUZ antennas in the top right corner of the photo. The larger ‘vertical stovepipe’ is for 40-meters and the smaller one is for 20-meters.
Using sheet brass or copper, (available at most hobby stores). Cut two pieces 5 9/16″ wide and long enough to wrap around the PVC pipe, plus a 1/4″ overlap for the solder joint. Tin the overlapped area and solder to form the cylinders.
(A rule of thumb for the length of the cylinders is: PI times the diameter of the pipe used. However, for a lower angle of radiation, make them shorter, as shown with the 5 9/16″ length (for 20-meters). That modification is 80% of the rule of thumb, or PI * D * .8).
When mounting the cylinders, the space between them should be the same as the outside diameter of the pipe. Starting 1/4″ below the lower cylinder, wind a 12 turn coil (11 full turns plus two half turns).
Mount the SO239 connector about an inch below the coil.
Wiring:
The center terminal of the SO239 connector attaches to the bottom of the coil. From the top of the coil, the wire is routed up the center of the PVC pipe to make a connection to the bottom of the upper cylinder. The ground side of the SO239 connector is routed up the inside wall of the PVC pipe to connect to the top of the lower cylinder. The cylinder connecting points are 180 degrees from each other. This antenna will operate in just about any location. It works equally well sitting on a table or up on the roof, or wherever. The only thing it doesn’t like is the coax being coiled over itself. Keep your lead-in coax straight. The length of the lead-in coax is not important. Build one and you will be amazed. It won’t take the place of a beam antenna at 80 feet. However, if you can hear them you can talk to them.
This information was assembled by WX5JF, ex-KD5RAK. He says “his version of the RUZ works like a champ!”
73 de SK KA5RUZ
Ten meters
1″ diameter schedule 40 PVC pipe
18″ pipe length (estimated)
1.32″ outside diameter (space between sleeves)
3.32″ copper sleeve height
4.5″ sleeve length
Twenty meters
2″ diameter schedule 40 PVC pipe
22″ pipe length (estimated)
2.375″ outside diameter (space between sleeves)
5.5625″ copper sleeve height
8″ sleeve length
Forty meters
4″ diameter schedule 40 PVC pipe
38″ pipe length (estimated)
4.5″ outside diameter (space between sleeves)
11.31″ vertical sleeve height
14.5″ sleeve length