VFO Tuning with a CD ROM

The most difficult part of this operation is determining what CD ROM to use. Your favorite CD, a junk one that is useless (but doesn't look good), the kit CD ROM (kinda boring), or the ARRL Designer CD ROM? By being very careful, the CD ROM should not be damaged used in this manner. And which side? You can certainly have a shimmering appearance using the other side than shown in the pictures.

A "special effects" CD-ROM can be made with a Microwave oven. A Microwave oven makes a fractal pattern that gives some very interesting results. Plus a lot of fun, especially trying to do it without getting caught. Picture

A Tesla coil produces spectacular results, which is totally appropriate for the Tesla VFO design. This is a must see site at "CD Zapping" at http://www.electricstuff.co.uk/cdzap.html After this operation, the VFO will suck in signals like you could never believe! Picture

Three rubber grommets are used to hold the CD ROM onto the shaft of the tuning capacitor. A 5/8" rubber grommet is put inside the hole of the CD ROM first. Then two 3/8" rubber grommets are pressed inside the 5/8" grommet from each side. The 3/8" grommets will go in a little more than halfway, leaving the outside half showing on each side. This gives a very tight fit, and the two grommets in the middle provide a lot of stability for the CD ROM.

Take the CD ROM to the hardware store when purchasing the grommets, as the dimensions are not always marked the same as the ones above.

If the capacitor shaft is notched at the end, purchase a 1/4" wooden dowel stick, and split a short piece in half, and use it to round out the end so the grommets will be centered on the shaft when installed.