Lev's Antenna

Hello, I've just made theremax theremin. The lack of linearity makes it really hard to play. I've heard about Lev's antenna that makes it linnear. Has anyone built it? I would like to try it, but I don't know how to make it.

Our renowned Thereminworld member Christopher has it on his website with technical explanations and a "howto".

Ooops, his website seems to be offline! So do a search via the wayback machine which should deliver you the archived version of the pages.

I can't find it, so ask if someone has built it and can write step-by-step tutorial

There are people who want to modify theremins but seem not to be able to do a simple search on the web?!?:

http://web.archive.org/web/20080430074156/www.oldtemecula.com/theremin/observations.htm

http://web.archive.org/web/20080515024832/www.oldtemecula.com/theremin/ult_antenna/index.htm

http://web.archive.org/web/20080517131828/www.oldtemecula.com/theremin/ult_antenna/index2.htm

You won't find many people who have built this antenna for 2 reasons:
a) The philosophy behind (flipped electromagnetic field instead of capacitance theory) is unproven and most theremin builders will not agree with it.
b) Tuning the additional tank circuit is very delicate and has to be repeated when the theremin is setup in another place with a different capacitive environment. (There are reasons why the pictures have all been taken outside in a free field environment...)

Thanks for links, I've never used webarchive.
Well, I will give it a try, that's not expensive and may give a great improvement. The only thing I don't like is how this antenna will look (spring in PVC pipe), standard metal rod looks way better. But maybe I will find tight transparent PVC pipe and nice shiny spring. I will also need ferrite rod coil and adjustable capacitor from AM radio that are connected in series, but in what order? main board->capacitor->coil->spring or main board->coil->capacitor->spring?

I saw something that can make also linear response: http://www.thereminworld.com/gal-pom.asp May 2005 - Upgraded PAiA Theremax by James Jacobson.
He says it "has a better linear response than a standard Etherwave, although it is not as linear as Etherwave pro" I can't find any info about it, so I will rather try Lev's antenna (maybe it will give etherwave pro response).

board -> capacitor -> coil -> antenna!

BTW: The Etherwave Pro's linearity is due to lots of additional circuits, including dynamic coupling between the oscillators. The Lev antenna will never give you this. And the range and linearity of the newest Etherwave Standards (if well adjusted) is very good and not comparable to earlier models. I wish you all the best but I'm not convinced that you will really get a linear 6 octave range with the Theremax...

Clara Rockmore used to say that one of the reasons why modern thereminists have so much difficulty with their instruments is that they are too "greedy". They want 6 or 7 octaves in their playing arc, while Clara had only the traditional three and a half octaves.

The more notes you have in your playing arc, the smaller the spaces between them and the more difficult they will be to control accurately. The only people who really benefit from range at the expense of control are experimental, aleatoric musicians who do not require precision.

Imagine a piano keyboard on which the ivories, instead of being the standard seven eighths of an inch wide, were just half an inch wide, so that more notes could be added without changing the keyboard's overall length. It would be extremely difficult to play and you would constantly be hitting wrong notes.

Same with the theremin.

Well, maybe it wont be as great as Epro, but my mission is to get to it as close as possible.
So the best option would be to add octave control like in etherwave pro to choose 3 octaves you want to play. That really makes sense, since I'm not going to use highest and lowest octaves at once.

If you use a pitch preview, you can switch registers on your theremin right in the middle of a piece with no problem. The Etherwave Pro, the Ethervox and the SERIES 91 theremins change registers without altering anything else (such as the note you are playing or your linearity).

[i]"The Etherwave Pro, the Ethervox and the SERIES 91 theremins change registers without altering anything else" - Coalport[/i]

I think that (probably) the above listed Theremins are the only ones (presently) able to do this.. All the above theremins employ 'unusual' circuit topologies.. and exploit digital and analogue 'tricks' and/or voltage controlled synthesizer circuits to achieve octave switching.

I do not believe there is a way to achieve the above using a conventional heterodyning Theremin circuit topology - Changing the frequency of either oscillator of a 'conventional' Theremin (as in, applying a bias to change its 'home' frequency in order to change the heterodyned audio frequency) must affect both the octave coverage (range) and linearity.

There are ways to do it with a heavily modified heterodyning Theremin circuit (using phase-locked-loop frequency multipliers on both variable and reference oscillators) - but I believe you will find that ALL Theremins which do range switching at present, use digital methods of heterodyning, or use voltage controlled sound generators... And the Moog Theremins which use these methods all sound great!