"The Tesla antenna is a form of wireless antenna or wave launching structure developed by Nikola Tesla in which the transmitted energy propagates or is carried to the receiver by a combination of electrical current flowing through the earth, electrostatic induction and electrical conduction through plasma with an embedded magnetic field."
- Gary L Peterson in "Rediscovering The Zenneck Surface Wave"
This is an area for scientific and artistic license. There is still much debate as to what exactly Tesla was up to with his transmission and reception of power systems. ( See Joel Young's blog comments in Design News Magazine on July 8th, 16th and 28th... http://www.designnews.com/blog/The_Weird_and_Wonderful_World_of_Wireless/index.php?text=tesla+antenna+
I experimented with two types of Tesla antenna design. The first is similar to the flat spiral "Pancake" coil that is seen in several of Tesla's patents. The second is a peculiar "Football" coil made of two cones.
For the basic spiral antenna, I used a 6 foot length of 14 gauge solid copper wire, and bent the wires by hand, coil by coil. I used a needle nose pliers to begin the core spiral, and after a turn or two, gently but firmly worked the wire around with bare hands. I soldered on a short vertical antenna to the centre loop. In retrospect, It would have been better to make the vertical end part with a one piece construction.
Keep working the wire to eliminate kinks and bends, then make sure the coils are evenly spaced. I soldered on the vertical antenna last.