Crystal Sets...
Some photos of a couple of vintage crystal sets in the process of restoration.
Introduction
It was my little green plastic 'crystal set' that first sparked my interest in radio half a century ago. It wasn't a real 'crystal set' as it used a germanium diode as the detector. But I can still remember the magical feeling surrounding being able to sling a wire up into the trees and receive a station some 15km away across the Mallee.
That magical feeling surrounding radio still persists for me a half-century later.
Unknown Crystal Sets
I have two of these sets that were given to me by my late Father-in-Law are in poor condition. I cannot remember exactly when, but I think it was when I was 'courting' his daughter nearly 40 years ago.
I think they are homemade as there is no brand name on them. The light grade wooden panels of one of the two sets appear to be re-used from another product and have "FLOR" and "REGALIA DE LA REINA" faintly visible. Searching on the 'net shows that "Regalia de la Reina" is a brand of Cuban Cigars which was imported as long ago as 1868 in Australia (see advertisement image below).
It would seem reasonable to assume that, although these two sets use almost identical electrical components, they have been homemade and built into suitable enclosures that were handy.
Getting these two sets going might be a little complicated. Perhaps the parts from the two can be combined to get one functional unit. Restoration of the wooden panels in particular will take some time to do. I have the complete sets of components for both sets (including the nice variable tuning capacitors - see image for an example of one) and so perhaps two sets can be made functional.
Time will tell.
These two sets have a separate antenna coil (the small one to the right in the image on the right) and a tuning coil tapped for the detector. The design of the tuning coil of these two sets is different to the tuning coil of the AGN set below. The AGN set has one winding which is tapped for connection of the detector and antenna.
The detectors of these two are 'true' crystal detectors with both the crystal (galena...?) and the cats whisker contact wire exposed to view.
AGN Brand Set
This is the third of three crystal sets that were given to me by my late Father-in-Law. This one is in the best condition of the three and I am in the process of getting it functional again.
I have identified it from this information from the Power House Museum.
I have a set of headphones that came with the set of a similar construction to those in the Museum picture, but they are not "Emmco" brand. The ones that I have are marked "Trimm Dependable". They are not functional so I have bought a set of later model 'refurbished' headphones of the same "Trimm Dependable" brand via e-Bay from the US.
It may be an option to ship the non-functional headphones to the person(s) from whom I bought the re-furbished headphones (as they are remarkably well done), to get them re-furbished. I will think about that for a while.
The original detector as shown in the Power House Museum link has been lost for my set.
In its place is an enclosed barrel-shaped 'modern' version of a cats whisker detector. It is still a 'real' crystal detector as you have to fiddle with a knob/lever arrangement to find the 'sweet-spot', so I am not too distressed about the substitution.
I need to run a long wire antenna for this and the other sets to get enough signal to overcome the forward potential of their cats whisker detectors.
Initially the plates of the tuning capacitor were shorted together. This was caused by the supporting bakelite back plate being warped over time due to the spring tension in the rotator plates mechanism. I had thought of reversing the plate to get it to straighten over time.
However, considering it took 80 or so years to get to its present state I figured it would take as long to bend back. I settled for adjusting the pivot seat nut to position the rotator plates central to the stator plates.