[Milsurplus] Mackay 123B

[Hubert Miller]

I have not seen one of the 'emergency crystal receivers' among 3 varieties, with a fixed crystal. 
I think the early fixed crystals were somewhat fragile and susceptible to moisture ingression?
But I don't have any evidence marshalled. I'm just recalling some instructions that came with 
jim-crack early toy crystal radio with fixed crystal. 
-Hue 

>well they all had  the manually diddled   adjustable  crystal detector? or  were the later ones  replaced  with a simple  diode?
Ed#