Human-powered Electricity Generation

This one-man bicycle generator is of unknown date, but apparently the components suggest it is British. Certainly 'Dunlop' is written on the saddle.

The design is quite different from the German versions above, and unquestionably has two stages of step-up before the output shaft. The diameter of the output pulley (presumably there was one) is unknown.

There is no support for the operator's arms, unlike the bicycle generators.

You may be wondering what the Admiralty wanted with pedal-operated generators. The answer is they were carried ashore by landing parties together with an Aldis signalling lamp, for visual communication back to the ship. Since this was line-of-sight communication it was relatively secure against interception.

The Special Operations Executive was a British cloak and dagger organisation set up in July 1940. It dealt in espionage and resistance in occupied Europe. This pedal generator was intended for recharging radio batteries.

Now why use batteries, I hear you cry? Why not just plug your suitcase transmitter into the mains? Because the German forces would sneakily switch off the power to one area at a time. If the clandestine transmission suddenly stopped, that located the transmitter to that area.

Other methods of charging batteries in the field included the "beach chair" pedal generator, bicycle generators, wind generators, and even portable steam-driven generators. (made by Stuart) It seems unlikely the steam engine was used for clandestine operations.

Source of info for last paragraph: Wireless World for Sept 1975, p442

Apologies for dire image quality but the Museum Staff have so far failed to find a better version.

This shows a pedal generator with chain and generator shrouded. I wonder if it really was "...far more efficient than any other available equipment". It seems highly unlikely unless Redifon came up with some miracle technical advance that has since been forgotten.

This machine was presumably intended for militiary field use. It's not clear why the Post Office would need them.

It is also a good example of why you shouldn't use too many type fonts on one advert. I count at least eight, and possibly nine.
Dear me.

Source: Post Office Engineering Journal for Jan 1957

A group of US soldiers power a radio set with a GN-45 hand-crank generator during WW2. At top right a man is using a battery-powered walkie-talkie.

The GN-45 generator had a combined dynamo that generated 6 Volts DC for valve filaments, and 500 Volts DC for anode supplies, with separate windings and commutators. (B+ supply) It was mounted on three legs, with one longer leg incorporating a seat. There was an earlier GN-44 generator.

There is much more info here.

Looks very much like a posed photgraph.

British hand generator for clamping to a table. Yhe text (where it's readable) says it is forcharging 6V batteries.

Apologies for dire image quality but the Museum Staff have so far failed to find a better version. Some the text is just about readable.

Virginia Hall (known as the Limping Lady because she lost a foot in a hunting accident) was an American who in 1941 became the SOE’s first female resident agent in France, engaged in the desperately dangerous business of organising French resistance. She survived the war and was awarded the Distinguished Service Cross, one of the highest US military honors for bravery in combat. This was the only DSC awarded to a civilian woman during World War 2.

Here she is sending morse on a clandestine radio, with power coming from a hand generator improvised from a bicycle. The cat on the window-sill is a nice touch.

I think it's a brilliant painting. It took a little tracking down but it is called "Les Marguerites Fleuriront ce Soir" by Jeffrey W Bass. The phrase means "The Daisies Will Bloom Tonight" and is the sort of coded message much used by the French Resistance. It is oil-on-canvas and was painted in 2006. Mr Bass has a current website here.

I haven't checked yet, but I suspect all the details of the radio etc will prove to be correct.

There is much more info on Virginia Hall here. It is a remarkable story.

This WW2 German device is a combination of a hand generator and a battery tester. (The lower section) There was room to store two batteries in the lower part of the case. It was used to charge batteries for German VHF transceivers in the field; it was called a "Handlasesatz a", often abbreviated to "HLS a" which can be seen on a nameplate just below the grey generator body. "Handlasesatz" according to Google Translate, means "hand laser set" which I think we can agree is wrong. Can anyone help?

The batteries were 2.4 Volt Nickel Cadmium, of 28 Ah capacity. They ran the 2.4V heaters in the transceiver valves directly. The HT (voltage currenrly unknown) was generated by a vibrator with synchronous rectification.

The crank handle was stored inside the case for transit.

There is a great deal more information here.

This shows the top of a different HLS a, showing the carrier strap and the lozenge-shaped identification bump at bottom left, next to the lid. This was needed for identification in the dark, as both the transceiver itself and a crystal calibrator (three round bumps) came in boxes that were otherwise identical. Note HLS a written on the right end of the case.

The little hinged lid opens to reveal a resonant-reed frequency meter. I have read that this allowed the operator to crank at the optimal rate for charging a battery, but that makes little sense as the electricity must have been rectified to charge a battery. Mysterious.

There is a lot of information on the transceiver itself here.

This is a more recent generator that was in use in East Africa. It was called the Mk810A generator also known as 'Generating set AC 45W 110V, hand or pedal driven, No1 Mk1' The pedals can be unscrewed and replaced with handles. (The two vertical black cylinders)

There is a voltmeter mounted on the top of the generator unit.

There is much more information here.

This particular machine sold for £217.60 inclusive of premium, at auction. Not much...