Perhaps a bit of a review of something most would not think about here, but may be helpful to anyone buying this as a present for a younger relative.
I recently saw elsewhere this radio mentioned, so I thought as a pleasant diversion I would obtain one of these and see how it went (as they are reasonably cheap - £5 at the moment).
My first thoughts on opening the box was that the product was generally a bit cheaply made (expected really). On looking at the instructions I found that for one thing there was no schematic, and the instructions really required some skill or expert knowledge. Perhaps more serious is that the (supposed) Germanium crystal diode was marked ST4148 (err....).
I proceeded to construct, finding it tricky at times, but the real point of problem was that the brass tuning slider did not readily contact the coil throughout the range. This required careful adjustment (bending of slider rod).
I did finally get things working, with my loft long wire aerial and plumbing system earth (three stations, one of which loud enough for reasonable listening - I should point out that I did not spend a lot of time with the many possible variables). The original diode gave no response except for some noise (high imedance so some kind of picked up noise?). My working system used a Russian D311 diode (Genuine Germanium and seems a useful diode for crystal sets). I plotted a curve for the ST4148 - Silicon as suspected.
Looking online I notice this set (or very similar design) is sold elsewhere, and another builder (I think in the States) showed me part of a different manual showing a schematic, which was identical to the one I drew from the circuit.
Like most things these days it appears to originate from China.
All in all, an interesting deviation from serious stuff, but I think that many children who received for Christmas this will be dissapointed. I have been tinkering with crystal sets, and found my 85mm 50 turn multitapped coil (24SWG) with tuning capacitor (the kit uses self capacitance of coil rather than additional capacitor) with D311 diode and using the same aerial / earth setup gave far superior performance. It does seem useful for a minimally working setup for reference though.
https://www.theworks.co.uk/p/educati.../5015934323670