Two homebrew receivers

[Rhombic]

Could someone pse shed light on these two homebrew receivers? I’m supposing that “Wireless1” predates “Wireless2”. How can they be described? What is the purpose of the two coils on the left of “Wireless2”?

In “Wireless2”, I am supposing ATC stands for “Aerial Tuning Circuit”; but what about REAC and CCC? Does anyone recognise them as popular designs from the various magazines of the 1920s?

Thanks in advance

R

[Anthony Thomas]

Those are both typical designs of the 1920s, I would describe those two coils on the left of "Wireless 2" as a variable coupling coil. One is movable and varies the amount of coupling between the coils.

Reac I would think is for reaction or as Americans say "tickler" and varies the amount of feedback applied to the grid circuit.

Is that by any chance the late Fred Judd in the photo on the left?

[Rhombic]

Thanks for your prompt and helpful reply. So Reac would be what is known as 'reaction'; I believe that if this was overdone, the set would go off into self-oscillating and cause interference in the immediate neighbourhood. I can remember being reprimanded by my grandmother when I was listening to Morse (minus BFO) via her broadcast receiver in the early 1960s. She said that the 'oscillation' would annoy the neighbours; at the time, I didn't know what she was worried about because the reaction (regeneration?) receivers were well before my time.

About Fred Judd ... that's a name I remember from 'Practical Wireless', but it's not him in the shot.

R

[Anthony Thomas]

I remember seeing a photo of Fred Judd in Practical Wireless a few years ago that depicted Fred in a similar situation out in a garden experimenting with wireless equipment.

[greenstar]

I'm fascinated by these early sets. Set 1 I would think is an earlier design, 2 valves visible, tuning by a sliding coil - not tapped but inductance varied with a sliding contact - and variable condenser, both separate units. He may have started with a crystal set, and added a valve detector and amplifier, or an rf stage - probably not a regenerative set as it would be tricky incorporating a reaction winding in the coil. A selection of parts assembled on a board or bench. Having two valves was pretty good pre 1920, or he may have just been using what he could get hold of. The second set is more say, 1923-4 design, all in one cabinet, ie, a 'set', although this was done from tthe mid teens in the USA. I may be corrected, but those swinging honeycomb coils are about 1922-23, as variometers were used more later on, being more efficient and freer from hand capacity. Yes, I would guess that is a regenerative set, the reaction coil being one honeycomb, and it looks like it had one rf stage, as there is possibly an interchangable rf transformer on the panel between the first two valves. You'd change range by swapping coils, and possibly need to change that transformer at the same time.
Tony

[Nickthedentist]

Pics of Fred Judd here: http://www.fcjudd.co.uk/

N.

[Rhombic]

Thanks for the various replies, especially the detailed post from Hexode. I wish that I could date the pictures, which are of UK origin. Do people think that the case of Wireless 2 was home made?

M

[greenstar]

Very well made if it was. The panel is engraved, so possibly manufactured, or maybe a kit - this was a popular way of buying a wireles.
Tony

[greenstar]

As a guess, if the kit was 'state of the art', photo 1 circa 1918, photo 2 1923?
Tony

[Rhombic]

Further to the two receivers, I've now found amongst the collection of old photos the circuit diagram and a description. It appeared in the magazine 'Modern Wireless' in 1924. The three-valve Rx must surely be the one which he built. Regarding the cabinet, he was an upholsterer and an expert carpenter so I guess that was also his own work.

Hope the circuit is of interest ...

M

[lesmw0sec]

Yes, those would make a nice little transmitter. I built a similar set years ago and can recall my neighbour shaking her fist at me through the window when I overdid the reaction.

As P.P. Eckersley said: "Don't oscillate - please don't do it"!

[greenstar]

I may be wrong, but it doesn't look exactly the same. The circuit shows three honeycombs, one for reaction. The set pictured in post 1 looks like it uses two and a variable capacitor for reaction, as the control is on the panel.
Tony