Hi all,

A friend gave me an old radio, or rather, parts of an old radio ..... and I am trying to find out what it is.

There is very little information to work with ...

Valve socket has the following stamped into it:-
Manufactured for Radio Company of America by General Elect. Co. USA Model UR-542 Licensed for Amateur or Experimental Use only Patented Dec 23 1919

I found one article which stated that these sockets were used for early Radiola radios, 1920's.

The above valve socket has a DI valve in place, 4 pin, 3.5v heater, 25 to 30v etc..

The second valve socket appears to be porcelain, 4 pin also. No valve.

There is also a Dubilier Mica Condenser, TYpe 600.

Seems to have an earphone socket with variable resistor.

What do you think?? Is it a radio with parts missing, or a 'cobbled' together 'project' ??????

I have searched quite a few sites trying to identify the dials etc ... but I found nothing similar

Cheers,
Ian

‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾
Cheers, Ian

It appears to be a homemade project

Yep, I'd say home made ... plenty were back then and often literally on a breadboard.

It's interesting to imagine somebody listing to that set back in the day when the excitement of radio was real.

Yes very much a home made radio by a enthusiat.

To buy a commercially made radio was well out of the reach of many, there was hundreds of books and magazines giving construction details for all sorts of sets.

Edit: Something that occurred to me, looking at the coils and the tuning capacitor they appear to be rather small for a broadcast band radio.

Suspect it may be a shortwave radio.

Shortwave was a big thing during the 20's and 30's.

It would be a interesting project to get going again although there would be a lot of work involved.

How is it powered?

Would they be using the same transformer to run many projects?

Are the dials from broken commercial radios? or could you buy that as parts?

Nearly all of the radios of that early era were run of batteries of various sorts.

Depending how wealthy the constructor was generally the filaments were run of rechargeable wet cells (provided a battery charger and mains power was available which in out of town places did not exist) or dry cells like No6 bell cells or torch cells.

For such a small set a couple of D torch cells for the poor or perhaps a L.T block battery would have lit the filaments.

High tension (H.T) would have been supplied by specialised dry "B" block batterys.

Probably 22.5 or 45 volts as the circuit required.

B block batteries were ferociously expensive so even with a modest 2 valver listening would have been when something worthwhile was there to be heard.

For people whom lived in the country it was considered quite an achievement to hear music and news.

I remember a old chap telling me that as a young fellow living in a small county town during the 20's/30's where even newspapers were hard to get having locals asking him what he had heard "on the wireless".

There was a lot of "Wireless shops" about, Hardy's Radio Store, Royal Arcade Sydney, United Distributors, Sydney, Efco, Arncliff, Sydney and a host of others.

A lot of mail order and kits done in that era.

Thanks for the responses.

I have to agree with the assessments above ie. a project rather than part of a manufacturered radio. Pity, as I have worked on many Superhets and was hoping that this was a manufacturered TRF which I could resurrect.

Yes, Simplex, I am interested in getting it going again .... if I can get the bits and pieces that are missing, or modify as needed.

I guess that the key issue is to find a circuit diagram that suits the components that I already have. Most of the circuits that I have found so far include tetrodes and pentodes and high voltage.

I have been looking for a 2 valve TRF circuit using triodes and low voltage ie the DI valve working voltage of 25 to 30v. Haven't found anything close as yet.

Found data about the DI valve:- pin layout agrees; filament is visually and electronically intact.

Variable capacitors are 12 to 85pF and 14 to 87pF. Fixed Dubilier condenser is 168pF.

Any suggestions, circuit ideas etc etc will be warmly welcomed.

Cheers,
Ian

‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾‾
Cheers, Ian