replica RCA Antennas

Some do and some don't. I'm puzzled as to why that is even relevant?

Rudd (9/3/2007 11:18:59 PM)

I suppose I might be interested in some '12L14 1" cold drawn rounds' but I am not sure what they are! I suppose the "cold drawn" part means they are easier to bend than regular brass tubing, but please explain '12L14 1".' Rods, tubing? Diameter?

TIA
Alan in CA

Maybe tomorrow I will make the jig and try bending a volume antenna from 3/8" aluminum tubing I found at the hobby shop. 3/8" brass, both tubing and rod, seemed too hard to bend, and they had no aluminum rod. I have assembled brass fittings for 3/8" antennas, so there is no going back on the diameter. If the aluminum works all right I will buy a couple more for volume antennae. I was trying to think of some way to plug the end of the volume antenna if it were made of tubing (figuring that would be more esthetic), but then it occurred to me that if it were open and combined with a hole in the bottom of the far side of the case, it might provide a little ventilation for the electronics--rather like a chimney.

Er.. sorry, machinist humor, not understood here. I have 10 extra sticks of 1" x 3' solid steel rod, alloy 12L14. It'll bend, but it'd need alot of force, or be heated up to a nice happy light orange color first...

Rather too much for me to handle!

Yay! I successfully bent the volume antenna! Used a jig made from scrap pine board and particle board using the RCA antenna specs, and for the antenna material a 30 inch length of 3/8-inch/0.035-inch wall thickness aluminum tubing I bought at the local hobby store (one hardware store in town carries it too, I think). For anyone who might wonder, I can tell you that tubing is plenty tough; part way through one part of the jig was making ominous sounds, so I stopped and added another screw to it.

UPDATE

I think I got the high tech stuff working better than 50% reliably, ie the oscillators do that most of the time. So, since Rudd delivered the antennas and the thing appears to really like being hooked up to them, there is nothing left to do but proceed full bore with the furniture part of this lil project.

:)

Philip

Coward that I am, I am working on the furniture part before the electronics...

Well, I got the pitch antennae made, using 3/8 inch 0.035 in wall aluminum tubing like I used for the volume antenna. I made two lengths, 18 inches and 24 inches in height, with a 90 degree bend at the bottom to work with the connectors I have. I had hoped that I could make the 90 degree bend with a jig, like I did with the volume antenna (which has bends of 10.75 and 6.0 inches in diameter). I tried for a 2-in. diameter bend, but no matter how careful I was, I couldn't do it--the tubing flattened. I bought a proper (albeit designed for softer copper tubing) tubing bender at the hardware store, and by calling on my inner gorilla I was able to make good 90-degree bends (one inch diameter) in the aluminum tubing. So now it is on to the case/box for my Theremax. It will be somewhere between a Kees and an Etherwave--red oak, 18 inches wide, 7.75 in. deep and 6 in. high (457 X 19.7 X 15.2 cm).

Here's a picture of the jig and antennae I made:

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

The base is a scrap pine board; the shaped pieces are made from some scrap particle board, roughly shaped with the jigsaw, shapes finished with the rasp, and the edges grooved with the round file. The small round piece was intended to make a 90-degree bend in the pitch antenna, but that didn't work. I could still use it to finish bending the volume antenna. (Of course it sprung open a bit after being shaped on the large circular gizmos.)