Pitch Antenna Linearity

Posted: 12/15/2006 12:21:59 AM

From: Kansas City MO USA

Joined: 11/26/2006

Ok, I should not attempt humor.

My Etherwave is working perfectly.
And the person that told me what to do and how to do it was exactly right.
Specifically Mark Keppinger.

If you would please refer back to the links for the pictures I have in my earlier post. You will see that the amount of metal that I had to add to the simple alligator clip was tiny. And thus, he was off only by a gnat’s hair.

I was being facetious, and I apologize to those that helped if you felt I was offending you.

Buddy Craigg[/b]

You have to be careful of what advice you choose to take heed to.

In an attempt to get my pitch antenna straight up and down, I ground off the bottom 3/8” of my pitch antenna below the ferrule so it could become a ball socket and I could move it this way and that, but I lost pitch control.

A long time poster and someone trusted to know what he is talking about had suggested clipping an alligator clip on the top of the antenna would prove that I simply needed more antenna surface area.

After a few emails back and forth suggesting that I did not want to change the external visual aspects of my Etherewave, he suggested that I might be able to simply add the required amount of metal on the inside of the case to the pitch antenna circuit.

He was way off.
While the silly alligator clip trick worked on the top of the antenna, I had to add a lot of metal to the inside of the cabinet to get the pitch under control.

As you can see in the next series of pics, I had to add way more metal than this “know-it-all” guy said I would have to.

It’s just ridicules…
And this guy is supposed to know something.
Posted: 12/15/2006 10:07:26 AM

From: Kansas City, Mo.

Joined: 8/23/2005

Hi.. I am just catching up on the threads here.

Buddy, I would suggest that you, first, step back, take a deep breath, and remember that some degree of frustration is part of the electronic music game.

You have made quite a few mods to your instrument and it is hard to tell which mod is affecting what.

I would suggest removing the alligator clip and tuning the coil on your Theremin so that you can tune zero beat around 3 or 4 feet from the antenna. Start out with the case top removed.

Once you have done that, then put the case top on and listen to the pitch change. Remove the case top and tweak your coil so that the pitch changes in approximately the same amount in the opposite direction. Then when you put the case top on, the pitch should shift back into place.

Indeed, to remove 3/8" from your antenna might change the circuit a little however you need only compensate with the coil tuning.

The main thing: do only one thing at a time! That is, if you add an alligator clip, change the angle of the antenna, mess with the coil adjustment, then put on the lid -- you are trying to tackle too many variables at once. So... start with the lid off, alligator clip gone, and get your instrument working. Then introduce the lid. Personally, I wouldn't bother with adding metal to the antenna or even getting it perpendicular. Get it playing first, then introduce aesthetic changes a little a time, always being sure to keep the instrument performing to spec.

Hang in there... the problems you are reporting, though they appear major, are quite minor and remedied with a little calibration of the coils.

Hope this helps.
Posted: 12/15/2006 10:41:27 AM

From: Kansas City MO USA

Joined: 11/26/2006

reread my EDITED post above.

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