This single bubble tube is 22" in length from Absolutely Neon in Albuquerque, NM by Robert Randazzo. The diameter on the straight ends is approximately 0.75 inches.
It is filled with Argon 90% and Neon 10% gases.
The wire wrapping is 18 guage solid, tin covered copper. This wire holds its wrapped form well. There are 5 1/2 turns on the left side, continuing with a single crossing over the bubble to 4 1/2 turns on the right side.
Two copper sleeves are on either end, are made by using copper pipe-strapping pieces. To make them fit easily over the 3/4" tube ends, they were formed over a 7/8" ratchet nut (round) with the ends of the strapping pieces squeezed together with a large vise. Two 3/4" copper pieces were then connected by screw tightening over the end of the braided wire from the tuner. The joints were soldered to ensure a good connection.
The sleeves are able to be moved easily, but remain snug.
Teflon tape was used under the sleeves to protect the bulb.
One end (on the left) of the wire wrap is in contact with the copper sleeve on the left. The end of the wire wrap on the right is about 1" away from the other copper sleeve. DO NOT LET BOTH ENDS TOUCH BOTH COPPER SLEEVES! Only the one on the left side is touching. You will fry your device if both sides touch!
Single Bubble Plasma Tube