Eloy's Radio Shack Special

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Click HERE to experience what Sir Eloy heard... when his newly made Radio Shack Special first came to life!

A few years ago, I bought a crystal radio set to play with my little son. It was an experience of plain joy. It had so few components that it seemed a real miracle. Of course we didn't stop there and constructed other crystal sets...

We went further by buying some books on electronics and a book entitled "Aprenda radio, realizando sencillos montajes" (Learn radio by making simple receivers), edited by MARCOMBO 1988, author B. Figuhiera. It was a translation from the original French text. It is a good book, but we could not find the components that were necessary to construct the receivers...except for one of the designs.

We achieved to make an AM receiver that worked with a loudspeaker and batteries. We completed the crystal set with an antenna on the roof. Obviously the next step was to construct an FM receiver. I looked for help to a friend that was a fanatic of the radio and he recommended the ARRL handbook that I bought in 2002...from Amazon.

This is the greatest book about radio that I know of. But I have not, as of yet, read it completely. As I could not afford a good assimilation of the book in a reasonable time, I looked thoroughly on the internet to find a simple FM receiver without success...later in 2003, I tried again.

One year...and at last, an apparently friendly guy had posted exactly what I had been searching for a year ago. Therefore, when the summer holidays were near, I started collecting the needed components. However, I had doubts about the conversion of gauge numbers cited by Patrick and sent a letter to him without much hope of obtaining an answer.

And then came the second grateful surprise! Patrick not only seemed friendly, his fast answers was a really friendly one, in which he answered my doubts and offered his help in the 'components of the receiver' and after trip, 'the construction of the receiver'.

Of the difficulties I had with the unit, everything was soon solved. Patrick had asked me to describe the journey of the Radio Shack Special, because this would be beneficial to other people in making their own RSS. So I will describe them now...

The AWG type wire...It was clear that the gauge numbers that Patrick described had to be transformed into millimeters, which is the unit in Spain. Wires found in most European countries are also measured in millimeters.

The trouble or doubt I had was to know which gauge scale Patrick was using. I found three gauge scales: AWG, SWG and a third of which I do not remember the name (something like USWG).

Once I had which scale Patrick was speaking of, concerning the conversion from gauges to mm's, was then a straightforward task. The problem was not the conversion itself, but to know which scale Patrick was speaking of. Of course, thanks to his help, it was easy to surpas this difficulty.

1) The closest to the 22 gauge wire ( 0.0253" = 0.643mm ) is the '65' which has 0.65mm of diameter. The closest to the 30 gauge wire ( 0.0103" = 0.254mm ) is the '25' which has 0.25mm of diameter.

2) The second difficulty was to find such wires. I could not locate them at components' stores in my city...so I found them in a motor rewire enterprise, where the men who managed the business actually gave me more wire then what I needed!

3) The third difficulty was to find the original MPF102. I started with an equivalent one, but Patrick encouraged me to find the MPF102. I then started phoning all the component stores in my city, without getting a positive answer. But when I phoned the last shop, I was almost sure it would be impossible to find the MPF102 transistor. However, I got a delightful answer! With that, I purchased three of them.

4) I constructed the unit with great care during the holidays, but had noticed a 'wrong' capacitor! So I had to go back to the electronics' store and told the man that he had sold me the wrong capacitor. I then acquired the right one.

5) I double checked my connections and then turned the unit to ON. The apparatus did not work at all and seemed to need a strong current. I adjusted the variable resistor and suddenly the artifact passed from the silence to an abrupt sound that left me completely disappointed. I then went to bed.

The next morning I started by checking all of the electronic components and then I realized that a resistor was wrong...when I inspected it. I realized that the colors seemed to be incorrect. I carefully read the value needed, and yes! It was not the correct resistor! I had not re-checked this particular resistor, because I had no doubt that the man who sold me this component, could be wrong. So I replaced it with the correct ohmage, and eventually...IT WORKED ! ! !

By the way, it worked much better in 'Seville', than it did in 'El Puerto de Santa Maria'...which is a town in the province of Cadiz (where we spent the past holidays).

By this time, my son could not just watch anymore, so he constructed as well a simple short wave receiver published by Patrick. My son had a great desire to construct a short wave receiver since the installation of the antenna.

Finally he achieved his desire! I only helped him with the soldering and wiring the coil. Please click HERE to see my sons' Shortwave Receiver Project.

Patrick, I would like to thank you for all your amiability and support and, of course, for your great RSS design!

I want to thank you Sir Eloy, for taking on this fascinating project of the one transistor FM receiver. I am honored that you and your son took two complete challenged journeys...and without fail!