Theremin Antennas

Posted: 12/28/2008 6:17:33 AM

From: Maryland, USA

Joined: 12/13/2008

Parsa. I'm just starting careful work and planning on a Theremax kit, and I have plans for later adding a Lev Antenna. I'm gonna use clear pvc pipe for the vertical section containing the spring, with a cap on top, a 90 degree angle on the bottom and a short section of pipe horziontally through the right sized hole in the wooden cabinet, a snug fit. The outside diameter of the pipe I have is in between 13/16" and 7/8" 27/32"... Hmmmm might drill a 13/16" hole with a speedbore bit, then make it a little bigger with a half round rasp or sandpaper,,,?
It might seem that the spring rated at 9/16" diameter shouldn't fit into a 1/2" inside diameter pipe, but it does! The dimensions are all detached from so called reality, like wood, a "two by four" is neither 2 nor four inches no matter how you measure it.
The rings at each end of the spring might need a little squeezing to fit down the pipe. Below I will post the details of my plan.
Posted: 12/28/2008 6:18:13 AM

From: Maryland, USA

Joined: 12/13/2008

Clear PVC Pipe for an Illuminated "LEV ANTENNA"
This site tells you what it is:
This antenna is a coil spring kept slightly stretched inside a 1/2" inside diameter PVC water pipe. I saw an idea on this web site about making it from CLEAR PVC, so this beautiful spring is visible and I'm gonna do it! I'm gonna start the Theremax first with the stock antennas, make sure everything works fine, then I'll be ready to try this LEV Antenna.
Here are the parts I have ready to go:
I got the spring from Ace Hardware,
Century Spring C-253 9/16" diameter x 16-12" long x .054" spring wire diameter. It's a nice shiny stainless steel spring that deserves to be seen.
I got the clear PVC tubing from
1/2" schedule 40 10 ft. length 1395-005
(10 foot minimum, fifteen bucks, more perfectly good beer money down the drain, wait til you see what the elbow and cap cost!)
1/2" 90 degree ELL (slip) $4.42
1/2" Cap (slip) $3.94
Two pretty brass 1/4-20 x 1-1/2" long and brass nuts at my local hardware store, a little long, I will need to cut them and chase them off with a die.
I ordered the AM ferrite core antenna and the trimmer capacitor and the alligator clip and extra coax antenna cable (RG-174/U) from:
This site warns that they are behind on shipping up to 10 days after the order is placed, but they seem to have everything.
The clear PVC pipe has a slight blue tint, that gave me the BIG IDEA: to Illuminate the clear pvc pipe with Blue LEDs..... The Color of Electricical, as Eva Gabor would say in Green Acres! Ever seen a clear solid, glass or plastic, lit from the bottom with colored light? AHA, this proves I'm a genius.
Even better would be to have the led colors slowly fade in and out, blue with some red or pink fading in and out to make purple.
Even more betterer than that would be to tap the theremax circuit for pitch to control a low voltage LED 3 or 4 frequency color organ circuit so the plastic tubing will change color by pitch!!
That would be so cool, and it will satisfy those folks Les Paul refers to as people who hear with their eyes.... (there's gotta be something visual for some)
I'm gonna use plastic polish on the clear pvc pipe parts, you can find that in the car polish section anywhere, there are several brands, it's meant for cleaning up plastic headlight lenses, and it works great.
It might be March or April before I get this whole Lighted Lev Antenna happening, but it might be a lot quicker. I won't be mad if someone beats me to it, but I have a feeling I'm gonna be the "first kid on my continent" to have one!

Posted: 1/5/2009 2:37:17 PM

From: Escondido, CA

Joined: 2/6/2008

It would seem that antenna length is not real critical for theremins, so you might be able to make a 8' or 10' antenna work with some minor tuning.

For "pretty" antennas, I found 2 different long dipstick tubes at AutoZone that work very well. They are about 18" long and the bracket that is intended to mount them to the engine block can be bent to a more closed position to allow a quick connect attachment. There is also a convenient bump in the tube that prevents inserting it too far in. With a little ingenuity, I think I could adapt the Lev antenna to attach to a small piece of tubing that could be inserted into the pitch bracket.


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