New acquisitions to be seen at the Virtual Radio Museum


Ever Ready Portable Radio

See its relation using the same circuit

 A nice Ever Ready portable from 1939. It's a model 5214 and it's most unusual, at least in the UK, as it uses "side contact" valves. These were common in Germany and other places but not the UK, whose manufacturer's preferred octal based valves.

It came from Wimborne in Dorset.

Is the covering real snakeskin? I suspect this may have been cheaper than plastic in those days. Then again I don't recall seeing many red snakes. Perhaps they were wiped out in the late 30s when parted from their outer coverings?


Philips N4418 Open Reel Tape Recorder

 This is the Philips Model N4418, their top of the range open reel tape recorder in the 70s.

I picked it up for £10 from the local recycling centre after filling in numerous forms, presumably to imdemnify the workers, local council officials, the UK Government and Brussels beaurocrats if I accidentally electrocuted myself when plugging it in. Absolute and utter nonsense! What's the world coming to?

Fortunately the mains lead was intact, tucked into a little compartment. Were the recycling people breaking some sort of law not cutting it off!

£10 was a lot of money considering the showroom was not available for demonstrations, but I was very pleasantly surprised when I plugged it in, and switched it on, to find it was in perfect working order.

Even the perspex cover is intact. The only faults I could find were a slipping belt on the tape counter and a faulty bulb in the RH output meter.

Considering that the price of the machine when new was about 50% of a small car such a mini, £10 wasn't bad. As the chap said when he quoted £10, "collectors are after them". Well one was and I'm very pleased I coughed up the cash.


Horn Loudspeaker

 An early horn loudspeaker

Standing on a mahogany base and having a lacquered brass adjuster and connectors, this loudspeaker probably dates to around 1922 or 1923. It was made by S G Brown who were a leading company in the early days of audio amplification, particularly of crystal sets, using magnetic amplifiers, before valves were commonplace.

This example, which has a horn opening of 12" and stands 21" high, appears to have been restored, or at least repainted. The impedance of the energising coil is 4000 ohms and would have been ideal for connection to a crystal set in place of the usual headphones.


Stella ST404T

 Newer than my usual purchases, this Stella "All Transistor" ST404T dates from August 1960. It looks as if it just came out of its box for the first time and worked perfectly when three "AA" batteries were fitted.

 

WW1 Trench Transmitter

 This is part of a WWI Trench Transmitter. Encapsulated within the wooden box is a step-up transformer. The metal fittings on the top are parts of a buzzer which interrupts the battery supply. There is an iron stud protruding slightly in the centre of the top panel which is magnetized when current passes through the transformer primary winding. This attracts an iron spring (missing) which carries the current. As the spring moves toward the iron stud the current is broken and the spring returns to its current carrying position, from where the cycle repeats.

The high voltage produced by the transformer secondary winding provides the energising current for the morse code transmitter.

A more complete example can be seen by clicking the picture.

French Galvanometers

 These are two similar examples of a mirror galvanometer, a very sensitive device for use with something like a Wheatstone Bridge.

The greater the sensitivity of current measurement, the greater the accuracy of measurement of resistance for example.

I bought these from a chap in France, where I imagine they were used in a Physics Laboratory. This particular design was invented by a chap named D'Arsonval.

The mirrors are presently detached but normally would be suspended so that they are visible through the front window. A light source can be directed at the mirror, which reflects a spot onto a remote scale. Inside the case is a horse-shoe magnet and the flux from this reacts with the field developed by current passing through a coil mounted with the mirror. The result of this interaction is a mirror deflection.

English Galvanometer

 This is an English galvanometer, probably also from a Physics Laboratory. This type operates as an ordinary moving coil device and has a pointer which deflects when current flows through the instrument.

Both the pair above and this model rely on accurate setting up by altering the height of their feet.

 

Eddystone 770R 19-165MHz click to see

World War I but what is it? click to see

RAF Test Meter

 This meter measures a little over 2 inches across and attracted no interest to buyers, being described as WWII. If it had been correctly identified as WWI, I might have had to pay ten times the sum it went for.

It probably dates to 1917 or 1918, as before then it would have been inscribed "RFC" rather than "RAF".

The case is heavily nickel-plated brass and it reads 0-0.5Amp.

It once lived at the W/T Stores Depot, RAF Kidbrooke in Kent and it has No.4494 marked on the dial.

STC Radio

This STC radio made in 1931 or 1932 is their 2-valve AC table model.

 It has only three valves including rectifier and as you can see the minimum of controls. It has a multi-tapped mains input and was therefore universal, at least as AC mains was concerned.
Bigger picture (with cobwebs) below

and click the pictures to see more about this set

The name "Standard"is on the escutcheon.


Early Car Radio... what make is it??

click to see more pictures...


Calibrator, Crystal No7 MkI


Control for what exactly?? click to see more


Power Unit Type 234A

 This is the AC power supply for the R1392 and R1132 receivers although it's fine for powering lots of wartime stuff.

Mine is missing its plug-in moving iron meter, but works OK without it. Under the light grey fuse panel lid there's a setting for changing the HT output between high and low.

Click here to see the circuit diagram


Sailor T128 Marine Transmitter & 24V PSU type N179

 This rather fine transmitter made in Denmark has 29 transistors and diodes plus a 12HG7 and three TT22 valves and is said to be capable of 250 Watts PEP output into 50ohms in the band 1.6 to 4MHz so neatly covers top band and 80 meters on AM or SSB. Running full power the drain is reported to be 11 amps from a fully charged 24 battery.

The TT22 has a 12 volt heater and can manage around 40 Watts anode dissipation The three valves in this rig are wired in parallel and use a pi-tank together with an aerial loading coil to match into almost any wire connected to the output terminal. The only downside for use on the amateur bands is that it's crystal controlled. Whether one can inject the output from a signal generator into a spare crystal socket remains to be seen. Has anyone tried this?

On top is the telephone handset.

Click for the technical stuff for the transmitter and it's mains and 24 volt power supplies


Radar Altimeter BC788 (new picture)

see a little more...

SCR522 (new picture)

see a little more...


 Waiting pictures...

More 1920s radio components

1920s home-built radio chassis

Early Hallicrafters receiver

Heathkit Grid Dip Meter

Bush AC34

Vintage variometer

Morse reader

Another HP VHF Oscillator

HRO; "much modified"

The HRO was available in large numbers after WWII and was used as the basis for pepping-up using modern valves by many radio amateurs. The awkward tuning arrangement wasn't important when looking over an amateur band. All you needed to know was the band edge settings on the dial. Actual frequency was relatively unimportant. The resetting accuracy using the dial's vernier reading was very useful.

The design of the HRO must have been good as both the Japanese and the Germans copied it during WWII.

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