Geoff Roberts

HG Wells Time Machine Crystal Radio

HG Wells Time Machine Crystal Radio

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Further information on this radio is at my website.

I decided to name this radio The H.G. WELLS 'Time Machine Crystal Radio' because it belongs to a Bygone age when things were made simply and very well engineered mechanically. Its really out of its time in this day and age. It works extremely well with its 'Dave Schmarder style Spider Coils'

I made this radio for Ralph Stevens who serves on the 'British Antarctic Survey Ship' Lets hope he takes it on one of his trips to Antarctica . Wonder how many stations can be received down in the frozen wastes on a crystal radio. Full description on my main site shortly.

Take a look at the nice article that Thomas Witherspoon at Blog wrote about me and this radio. Thank you Thomas!

Loose Coupler Replica Detector

Loose coupler radio reproduction by Geoff Roberts.

Further information on this radio is at my website.

Clapp-Eastham Replica Detector

Clapp Eastham Replica Detectors

More details at my website

The 'Jules Verne' DeLuxe Brass Crystal Radio

Two coil crystal receiver.

I have decided 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 smooth travel. I have based this design on Dave Schmarder's #70 set

Two coil crystal receiver showing coil detail.
Two coil crystal receiver showing tap switch detail.

The Gillette Razor Blade Foxhole Radio

Razor Blade Foxhole Radio
Razor Blade Foxhole Radio, Closeup View

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?

Radio #3

Crystal Radio Built By Geoff Roberts

Radio #3

Replica Perikon Detector

Perikon Detector, Close Up
Perikon Detector, Front View
Perikon Detector, Back View

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 noticeable play at the crystal contact points so I ditched the ready made 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 I've made for him will cheer him up to a speedy recovery.

Earth-Station MkIII

Homemade crystal radio

Earth-Station MkI

Crystal radio built by Geoff Roberts

Crystal Radio

Headphone Impedance Selector Box #1

headphone matching transformer for crystal radios

matching transformer schematic

Using Dave Schmarder's 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