H. P. Friedrichs (AC7ZL) Homepage





My Books 

My Books

The Voice Of The Crystal


This is the place for interesting news about The Voice of the Crystal.

The Voice Of The Crystal Referenced In AP News Story!

Michigan man listens to faraway tunes on a homemade crystal radio

Source: AP - AP Wire Service Aug 13 13:11 * Photo Advisory MIBAY502

An AP Member Exchange By FRANK C. LEE The Bay City Times

BANGOR TOWNSHIP, Mich. (AP) _ John Schwarz hears voices.

The Bay County resident picks up radio programs from as far away as Cuba and Ontario, Canada, on his homemade crystal radio sets that require no batteries or power cords and cost him less than $20 to build.

``They are inexpensive, simple to build, offer hours of entertainment and will last for generations,'' said Schwarz, 53. ``With a lot of kids now, they'll get behind a computer and that's it, and don't have the patience to maybe work at something that might take a day, and they are surprised they can hear music on these things.''

Schwarz has tinkered with crystal radio receivers ever since he built one for a science fair as a seventh-grader at Bridgeport High School. He now works as a repairman in engineering and maintenance for a hospital.

``In a lot of countries, in remote islands or someplace where they don't have a local station, that's how a lot of people are able to listen to news and know what's going on, by shortwave radio,'' Schwarz said.

These simple radios can receive AM stations as far away as 1,000 miles and FM stations, too. Most of these radios are built using a simple model - a wooden base, a hand-wound coil and a few components from Radio Shack.

``Their only source of power is from a wire antenna _ no batteries or plugging in,'' Schwarz said.

According to H. Peter Friedrichs, author of ``The Voice of the Crystal: How to Build Working Radio Receiver Components Entirely From Scratch,'' crystal radios use no tubes, transistors or batteries. Wireless signals are transmitted in the form of radio waves. When the energy strikes the radio antenna, it causes small alternating currents to travel up and down it. Certain crystals like carborundum, zincite, bornite, silicon, galena, molybdenite and iron pyrite are commonly used in crystal radio receivers. The crystals used in the radios are about an inch in length. One of the best crystal detectors uses the galena crystal. If probed with a tiny wire, called a ``cat's whisker,'' the point of contact between the galena and the wire forms a very sensitive detector to extract the radio signal.

``The reason why they went out of style is because kids want instant gratification. They want to plug it in or throw some batteries in it and have it work. And I think that they miss how much they might enjoy something like this that they made,'' Schwarz said. His hobby allows him to learn a lot about other cultures just by listening to music from around the world. For example, Schwarz listened to the opera on one of his sets _ from a radio station in London, England.

``It's just amazing, and you'll never know what you're going to get. Some times of the year, the reception is better, but at night is what makes the difference. During the day, you don't get that much,'' Schwarz said. At night, reception of radio signals that are bounced off part of the Earth's atmosphere is greatly improved, so you can hear stations located farther away. Schwarz said he's heard from Boston, Chicago and New York.

``On a local station, with some of these radio sets, I have received signals loud enough where you had to `tune them off' the station a little bit, because it was too hard on you using the headphones,'' Schwarz said.

``I've received Spanish-speaking stations on shortwave, and that's something why I wondered why more kids aren't into shortwave reception that are taking languages in school.'' Schwarz said he's even tuned into broadcasts with his crystal radios, or ``free-power rigs'' as they are also called, from as far away as Geneva, Moscow and Tokyo, using a shortwave receiver version of the crystal radio. The broadcast radio wave from the station reaches the antenna of the radio receiver, where some of the wave's energy is captured by the radio antenna. There's enough power in the radio to run headphones or a small speaker.

``And sometimes, I've listened to some stations that are broadcast in French. Some of the music that you hear now that's popular; you might listen to on one of those stations and hear that same song, but sung in French beautiful. There's a whole different world out there,'' Schwarz said.

AP-CS-08-13-01 1409EDT Received Id AP10122589D762D5 on Aug 13 2001 13:37

The Voice Of The Crystal Is Referenced In Teacher's Guide Accompanying Educational Media!

Library Video Company produces a wide range of multimedia teaching materials for use in the classroom. One of their video products, part of their Nobel Prize Science series, deals with Electronic Communication. A teacher's guide, which accompanies the product, recommends The Voice Of The Crystal as a useful classroom information source.

How Much Is Too Much To Pay?

While the distributors and resellers of my books are free to charge what they wish, The Voice Of The Crystal was intended to have a suggested retail price of $14.95. If you are paying significantly more than this for a copy of this book, you may be paying too much.

Some weeks back, I noticed that somebody had placed a copy of The Voice Of The Crystal for sale on Ebay. When the bidding had ended and the dust settled, the winning bid ran in the $40 range. Wild! But the insanity doesn't end there!

Even more recently, a colleague sent me an email directing me to check out one of the used book resellers linked to Amazon.com. There, a copy of this same volume was for sale at a price approaching $200! That's right! Two hundred!

I have no idea why my work would command such prices. I'm certainly not dead (yet) and the book is still in print. In any event, the one sure way to protect yourself against price gouging is to patronize one of my official distributors


(revised - 11/03/2005)