Crystal Radio Set Review

Our Crystal Radio has been popular over Christmas. The following is a review (unedited) from Canada (Thanks Bob)

A few weeks ago I got sentimental about the Rocket Radio my father brought home for me in 1958.

He was a Merchant Marine Radio Operator.

Back then, we clipped a bed-spring to the aerial and I was able to listen to AM stations over a thousand miles away, at night.

Those little radios were about a dollar, back in those days, but they are expensive now.

But I discovered the Mallinson  Crystal Radio kit on ebay and optimistically ordered two, one for me and one for dear old dad, now 86.

They arrived promptly.

The boy in the illustration in the kit had his radio in a cigar box so I emailed Mr. Mallinson who suggested that "Any box will do."

They have great customer support.

At the Dollar Store I found two little coffrets in unfinished wood which I then stained and varnished.

 

 

And the instructions.

There is a little 6-pac of connectors which, when I inquired again of Mr. Mallinson, can be used as a unit, or separated depending on my preference..

So for a couple more days I studied the parts, off and on.

The instructions are clear and easy to understand.

 

I had salvaged a toilet paper roll for the coil, but between us we decided it was a bit big in diameter, so I unrolled
a remnant of tinfoil and secured a narrower form for our coil, and a bit heavier.  The wire is quite stiff,

While the varnish dried I studied the contents of the neat little box the kit came in.



I concluded that the project is a four handed job; somebody has to be a human vise.

A likely looking neighbour (Sam) dropped in this past Saturday and over coffee, I suggested we have a go at the first kit.

He agreed; then I kind of rushed his coffee while I collected the materiel for the job at hand on the kitchen counter.



We put 25 turns on one end of the roll and taped it nice and solid with packing tape, leaving generous leads, the ends of which we sanded, to connect them to the circuit.

With a hacksaw we sawed off the roll at a good length to fit in the box and allow for any adjustments we might have to make later.

I drilled a hole in the centre of the right front of the box for the capacitor.  Then we debated how to secure the little capacitor inside the box so it wouldn't tend to turn with the knob.

I was for taping it in with packing tape but Sam wanted a professional looking job so I got him a little chisel out of my toolchest and he carved a neat recess to keep the capacitor from turning.

There are two screw holes in the front of the capacitor so Sam suggested we screw it in securely; he's a regular perfectionist.

I went through my machine screw bag and found one little brass screw the correct calibre. Meanwhile Sam drilled it a hole and filed it a countersink with a little round file.

It is amazing, the tools one has on hand at my age.

So we screwed in the capacitor; unhappily our little screw proved a tad long and popped off the plastic back.  That snapped back on, neatly and we then filed the screw a bit shorter.

Hoping we hadn't bent the innards, we boldly went on...

We couldn't figure out a way to use the 6-pac as a unit, so we cut it up, crosswise into three pairs.

The rest was easy for a four handed team like us; the circuit is very simple.

Unhappily we couldn't get the plastic connectors tight  enough to secure the diode and resistor, so we elected to use solder.

We moved the whole operation to my workbench and heated up the soldering iron and tinned all the parts.

For this you need a wet sponge to wipe the soldering iron on.

I held the parts in place with needle nosed pliers while Sam soldered them; he had won a soldering award in a previous life and hadn't lost any skill.

Getting excited we trimmed the plug off the earpiece and soldered that in too.

Being in the basement we grounded the receiver to the furnace and flung the aerial as high as we could get it up the parts shelf.

We took turns listening as we fiddled with the capacitor.

We discerned some hopeful static.

Keep in mind that this was in the afternoon, underground, with a solar flare going on and  there are no AM stations anywhere near here.

We called it a day, but the intention is to buy a clamp from a repair shop to connect the ground to a water pipe in the kitchen, try the aerial above ground at night, with no solar flare.

This kit promises us hours of fun experimentation...

One footnote; our little wooden box was a bit thick and the shaft of the capacitor wouldn't extend quite far enough to top attach the knob so we are in the market for a different knob or perhaps we'll dig a deeper recess for the capacitor.

All in all a glorious jolly afternoon.  Pix follow.

--Bob
Shediac, Canada

Eureka!
Good signal on first try.

More experimentation in order as the volume is a tad low.


"Thank you for a great, and honest review Bob"- Andrew