An easy to build AM radio kit based on the popular MK484 radio IC.
Building your own radio can be very enjoyable, and nothing compares to the feeling of pride you get when your finished kit is built and you turn it on! Even though you can buy ready-made transistor radios very cheaply these days, and a text book may describe the methodology of building one, with a kit you really do learn for yourself!
AM Radio
Covers the frequency range 531kHz to 1602kHz (MW and LW)
Includes all components including tuning capacitor and coil, headphone socket and headphones
Small enough to fit into your pocket but sensitive enough to pick up distant radio stations
Ideal introduction to electronics circuitry and soldering techniques
Supplied complete with solder, screen printed circuit board and comprehensive instructions
Q. Will this AM Radio work in spain and do you deliver to spain ?
A. Hi Alan. Thank you for your question. This AM radio transistor radio kit will work world wide. For delivery to Spain please email Exports for a quote.
Reviews
Nice kit - here are some tweaks.
Reviewed by: Rob Rusbridge - Friday, March 28, 2014
Nice kit. Goes together without any trouble and works at first try.
Mine was tuning only the low frequency half of Medium Wave, even after I had adjusted the trimmer (screw adjustment on back of tuning capacitor) for minimum, so I unwound 25 turns from the main tuning coil and slid the coil assembly close to the end of the ferrite bar to fine-tune the inductance. Taking off turns reduces signal pick-up but gets coverage to the high frequency end of the band, which is more fun for foreign stations after dark.
Kit will work just fine from 3V power source if you fit the zener diode in backwards and don't use the 9V battery clip provided.
Wire up the headphones so that the outer sleeve of the jack plug goes to the positive power supply, and the ring and the tip are joined together and onto the collector of the transistor. This makes the set less likely to oscillate as you move the headphone cables around.
If you suffer bad distortion on signals loud enough to hear properly, you can decrease the value of R3 to 22 ohms. This pulls more current through the headphones and you don't run into clipping so easily. It does increase the operating current to 9.5mA, though. Even with this modification, the set will work for around seven hours on a pair of little AG13 button-cell batteries, if you're tight for battery space. My test batteries came 24 on a card from a pound shop.
To make the set even less likely to oscillate, I put a 2.2uF electrolytic capacitor across the headphone connections (+ side to + power supply), and a little 0.1uF ceramic disc across C4. Any RF energy getting into the base of the transistor and amplified to the collector is then shunted into the + power supply by the 2.2uF and then dumped from there to ground by C4 and the 0.1uF ceramic, which means it doesn't feed back into the MK484 chip and cause it to oscillate. Set does not go loud enough for the sound pressure level from the earphones to be dangerous.
After dark, all sorts of foreign stations become audible. By day, pretty much local stations only. If you want to pick up more stations, it's more important to connect the negative power line to a good earth than it is to hang on an aerial wire. Don't expect this little set to work well in close proximity to interference sources like switch-mode power supplies (computers etc.) or noisy neon tube lights.
