A question about building an antenna

Hello evrybody, I recently ordered the minimum theremin set from Harrison Instruments, and building your own antenna is necessary. I do not know much about this, are there any guidelines for material being used and length that I can use to get the most range that I can out of it? Any help and feedback is very much appreciated, and thank you!

This is a very difficult question. There are no general rules for Theremin antennas, details depend o the theremin's circuit layout, i.e. if there is a coil in series or not.

Some self-builders have started with CB antennas, but didn't get a satisfying linearity and range.

I would take a telescopic antenna of ca. 50 cm out of an old radio and try out with different lengths. Remember that you will have to re-tune the theremin each time you vary the length of the antenna.

The pitch antennas for most professional theremins are approximately 3/8" (10mm) in diameter and about 17"-18" (430mm-450mm) long.

Most are usually plated brass, although I have seen aluminum used as well. The material is usually thin-walled tubing with a 0.30"-0.60" (1mm-1.5mm) wall. Anything much thicker would be too heavy and hard to bend (for the volume loop). Anything thinner can be bent too easily in use and more likely to kink while bending.

The correct size and length of the antennas for your theremin will depend in part on what the circuit is "tuned" for, although there should be an adjustable inductor in the circuit that would allow some variation.

As this is a kit designed and sold by Art Harrison, I would suggest you drop him a line and ask him.

On his website he provides a page of the "Assembly Instructions" for the Minimum Theremin.

Minimum Theremin Assembly Instructions (http://www.harrisoninstruments.com/101/101_assembly_instructions.html)

Mr. Harrison seems to favor plate antennas and he recommends a "test" plate antenna 6" X 6" (150mm X 150mm) in size. These can obviously be easily trimmed to suit.

Very, very much thanks to everyone for the detailed responses! They will definately help when I'm building the antenna.

I made my own antennas, and put what I learned here:

http://www.abarbour.net/tmax.html

I made these RCA-dimension antennas for a Theremax; ultimately they worked just fine, but required different adjustments to the induction [tuning] coils than the standard Theremax antennas. Depending on the characteristics of the circuitry, it is not impossible that a particular antenna might not be usable. I second the suggestion that you ask the advice of Mr. Harrison.

Alan, were you able to use the jig to bend the volume antenna(s), or did you have to use the tubing bender for that too?

The jig worked just fine for the volume antenna; but the 90 degree bend I wanted in the pitch antenna was too much and required the tubing bender. Of course the volume antenna could be straight, depending on how you mount it.