Geoff Roberts

Loose Coupler Replica Detector
Updated 24 Feb 10
Further information on this radio is at my crystalreceiver.co.uk website.

Clapp-Eastham Replica Detector
Updated 1 Jan 10

The 'Jules Verne' DeLuxe Brass Crystal Radio
Updated 23 Dec 09

I have desided to call this the Jules Verne set. Did you ever see the film '20000 Leagues Under the Sea'? This reminds me in some way like the inside of Captain Nimos Nautilus submarine with all its brass Dials. There is enough Naval Brass on this set to sink a Battleship!!

This set has Aerial tuner built in plus adjustable impedance output for any phones from 8 ohms to 5 K ohms.

The Aerial tuner coil can slide along the twin brass rail to get a closer coupling to the main tuning coil . I used a Berilium Copper spring to make contact with the rails and it worked out well with smoth travel. I have based this design on Dave Schmarders #70 set

The Gillette Razor Blade Radio
Updated 22 Dec 09

In ww2 our boys in the field and some in POW camps were able to keep in touch by listening on improvised radios. One was called a 'Foxhole Radio'. I was interested to see how well these radios work so I built this.

The idea behind this radio is that Gillette silicone coated the blades to stop them rusting and this coating plus the blueing of the metal and the contact with graphite in the pencil made a crude kind of detector. It works!

I have to perform some tests yet to compare with my other sets but it is very interesting and opens up some food for thought. How about a hack saw blade radio?

Replica Perikon Detector

Here is a photo of' THE NEW IMPROVED PERIKON DETECTOR #2'. I have again used Galena and Zincite Crystals. This little beauty caused a few headaches in the screw department. It had too much play in the threaded parts of the ball joint and there was noticable play at the crystal contact points so I ditched the readymade M6 screw and set about making one with close tolerance.

I had never cut a thread before on the lathe so it took a couple of attempts to get the right tolerance for a nice smooth but not too tight fit.

I can lock the main spindle on this detector and make it into a straightforward catswhisker by replacing the spindle crystal with a gold wire. All good fun and a nice project.

This Detector was made for Ernest Snelling a great chap and WW2 veteran who is still building crystal radios in his 80's.Hes not too well at the moment so I hope what ive made for him will cheer him up to a speedy recovery.

Earth-Station MkIII

Earth-Station MkI

Headphone Impedance Selector Box #1'

Using Dave Schmarders Überformer and the Ben Tongue (Benny) circuit.

Geoff is quite talented, not only in building radios but about anything you can think of. Here are his other crafts websites:

Crystal Radio Parts
Geoff's Gizmos 'n Gadgets