[GeoffK]

I decided to have a go at making one of these radios, bought from a Singapore site as it was under £5 including postage and arrived quite quickly. It went together reasonably well, the red plastic aerial ferrite holder needed one screw hole countersinking as the screw wouldn’t go into the tuner even after the edge was bevelled as it was hitting a couple of the solder joints and wouldn’t lay flat. I tried a diode instead of the 9018G transistor as the detector, a BA219 as it was the only one I had, a 1N916 should also work here. Because the agc is taken from the anode of the diode via the last IF secondary the cathode connects to the volume control end, unlike a conventional pocket radio with npn transistors where the cathode connects to the last IF transformer.

The radio has only been temporary put together along with a temporary speaker to try it, and it worked straight away. Only the oscillator trimmer, the one nearest the edge of the case on the tuner, needed some adjustment to get the stations in roughly the right place, this will be improved once the dial is fitted. It still needs some final putting together but I am tempted to leave the speaker as it sounds very good, it was quite a revelation as I wasn’t really expecting it to work all that well if at all. The quiescent current is around 20mA so would like to get this down a bit, possibly a larger value of base bias resistor or the output transistors emitter resistor added.

The 9018G transistors give plenty of gain in the IF stage, the IF transformers are spot on. The only components I used from my own parts was a 100uF capacitor instead of the one of the two supplied, and the 0.01uF mixer input coupling capacitor as, like others here, it was the only part missing. Orange sleeving was used on the resistor leads but they are so thin the sleeving wouldn’t go around the curved part. The gaps in the printed board for current measuring had wire from the offcuts soldered across rather than just solder to bridge them.