Styrofoam coil form 5

[ohmrun]

I have wound a coil on a styrofoam form. Does anyone know of any issues with a styrofoam form? I plan to use it in a device that is used outdoors. It's Q will be 100 and low inductance. It will also be part of a resonant circuit with circuit Q about 50.

 

[MacGyverS2000]

Any particular reason you think it will be an issue?

Dan - Owner

http://www.Hi-TecDesigns.com

 

[itsmoked]

Styrofoam melts at a low temperature. If that isn't an issue it will probably work. (for a while)

Keith Cress
kcress -

http://www.flaminsystems.com

 

[IRstuff]

Doesn't styrofoam also have a memory problem? Any pressure on it will cause a volumetric/density change, which could affect the net dielectric constant.

Why styrofoam? It's not exactly a strength material.

TTFN

FAQ731-376

 

[itsmoked]

Yeah it does. It also comes apart eventually. It also deforms to relieve any stresses.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[ohmrun]

I can't really find a bobbin of the size I need. 1.2 x 4 inches. Styrofoam is light weight, easily formed and low cost. I need the induction field from it to induce a signal into a wire. A 2 x 4 works, but I was afraid that it would absorb moisture. I did notice the styrofoam compressing at the corners as I wound it.

 

[Henneshoe]

As an alternative, how about composite deck boards? They are avaliable at your local home improvement store and are a little more sturdy and weather resistant. I think you can get it in the same dimensions as a standard 2x4 (1 1/2" x 3 1/2").

 

[Comcokid]

Styrofoam is mostly air. So much so that the dielectric constant appears to be near 1. In some RF and antenna tests I frequently use it to support cables or test items (all my work is at 3GHz or below). I've never seen it make more than a small fraction of a db difference.

 

[zappedagain]

I'vs seen hams that wind a coil around a PVC pipe. It has good strength and the dielectric will be mostly air.

http://www.hamuniverse.com/balun.html

Z

 

[itsmoked]

PVC would be superior to Styrofoam.

Keith Cress
kcress -

http://www.flaminsystems.com