Saturday, January 31, 2015

Crystal Radios

This time on my hands has led me searching for radios.  I remember my first crystal set when I was about Liam's age or a little older.

" Not long ago I rebuilt and put into operation a Heathkit CR1 crystal radio.  I hadn't built a crystal radio since I put together my first radio when I was 10 years old, nor had I used a crystal set since I was 13.  During the period of the mid to late 1950s, I owned at least three crystal radios of varying performance.  With the Heathkit, I now had a crystal radio that performed far better than any of the radios that I remember using as a kid and once again I was struck by the magic of building and operating such an utterly simple and basic radio receiver.  '

Suddenly it occurred to me that it might be fun to try my hand at designing and building my own crystal set from scratch.  Besides that, a former grammar school teacher I'm friends with suggested to me that school aged kids would have a lot of fun learning about radio theory if they could build a working crystal radio and he asked me to come up with such a radio..  Of course, this strongly reminded me of how, in 1955, my aunt gave me crystal radio kit to build and how that experience lead to my lifelong interest in radio and my career in electronics.  The memories flooded back and awoke in me that desire I think we all have and that is to pass along to others those things that have helped us.

 Well, I have given a lot of thought to crystal radios lately and I have concluded that the ultra-simple, very poorly performing crystal radios that most teachers have their classes construct are just not worth building.  Rather than try to force kids who are just not interested in how their technological world actually works -- and after all, most of us only want to use technology, not design or even understand it -- I think that building a crystal set should be limited to only those students who show a genuine interest in this sort of thing.  In my opinion, the only students who should build something like this are the kids I call a school's "the scientific elite" (but who others would call "the nerds").  I think that building a crystal radio should be done as an individual science project, but not as a class project.  However, and this is most important, any radio anybody builds should be worth building and should at least approach the performance of the Heathkit CR1.

    It soon became my goal to design a low cost, but good performing little radio that would not only be easy and practical to build, but would be something a young person would be proud of and want to keep and use.  Of course, this applies to adults too, even old geezers like me.  So, the following paragraphs will describe the little radio I have come up with.  Please be aware that because the little radio is very compact, it requires some very careful, precision soldering using a dangerously hot soldering iron.  Additionally, winding 7 feet of wire on each of two toroid forms is tedious and requires manual dexterity and skill.  Because of these difficulties, I am very much of the opinion that this little radio is not a project for very young (under 12) kids.  You must use your own judgment regarding whether or not this project is practical for you or your student(s) to build."

I really wish I had kept my ham radio license today.  I let it expire when I was raising kids and today they have a 2 year clause to get your license back if you let it expire.  Mine expired a long time ago and in all my records I haven't found any license in my old files.

Did you ever mess with radio?



  1. I have a nice old crystal set in a wood box. It uses iron pyrite and a cat whisker to tune stations and strangely enough it has a knob to control the cat whisker. It needs a little work. I really should get it out and hook it up. My headphones seem to have gone missing. I had a pair of old black bakelite headphones I used with it.

  2. I recall getting a crystal radio kit for Christmas many years ago. It was not too successful but then I was not very skilled at building or assembling anything either. I do recall picking up some faint little sounds of voices on it but I guess I lost interest and eventually lost the radio too.

  3. I am going to add a link what mine looked like except it had a capacitor to tune it also. It worked great except WLW in Cincinnati was over bearing. I would stay up all night listening for stations to go off the air so I could hear other ones!

    It is under crystal radio's lately or you can copy and paste the link.