Radio Restored
J. G. Trevor Owen describes the restoration of the GECoPHONE
BC 3250 wireless presented to the Daunt Rock Lightship in
1927
I OBTAINED this wireless set of 1924 in a village near Cork
recently. The condition of the set left a lot to be desired. There
were no valves, an inter-valve transformer was burnt out, the two
pairs of original headphones were not working, and there were a few
other deficiencies.
I had two suitable valves. The original valves would have been bright emitters (their filaments lit up). The valves I used were dull emitters of about 1928. I had first used these in 1935 when I built a short wave radio at the age of ten, and have had them since. I repaired the headphones and found a transformer; not, regrettably a gec one but a contemporary one at least. I got the reaction part of the circuit to work and now I have a model GECoPHONE of 1924 behaving very well indeed after many hours spent restoring it.
The power supplies originally were an 80 - 100 volt high tension battery plus a low tension 2 volt accumulator lead-acid battery in a glass container. I now use a solid state circuit 80 volt power supply from the mains and two 1½ volt cells in series for low tension. There is a rheostat in the radio to reduce this to 2 volts.
The GECoPHONE BC 3250 appears to be quite rare, as it was soon superseded by a newer model in a vertical mahogany cabinet with doors and with the valves and coils hidden behind the front panela much neater proposition.
The wireless is a detector with one stage of audio amplification, model O-V-I, using two valves. The radio signal was picked up on a copper wire aerial mounted as high as possible. The resulting audio signal was fed to the audio amplifier stage which could operate two or more sets of headphones.
It must be remembered that in 1924 there was only a limited number of commercial radio stations on the air with some form of entertainment and weather forecasts, and the hours of transmission were limited. Of course wireless traffic was increasing rapidly between ships and shore stations, mainly in Morse and strictly business.
The wave length coverage of this model was about the same as today's medium and long wave bands using plug-in coils. At the time the long waves were considered more favourable for long distance coverage. With careful use of the reaction control long distance stations are easily picked up.
Many benevolent sources at that time presented wireless sets to ships, remote lighthouses, etc, and this one was presented to the Daunt Lightship by the Daily News and The Star Fund as indicated by the engraved brass plaque on the left hand side of the set.
Such radios must have been a boon to people like the crew of the Daunt Rock Lightship in 1927, opening up a new expanding world to them.
© J. G. Trevor Owen, 1997
I had two suitable valves. The original valves would have been bright emitters (their filaments lit up). The valves I used were dull emitters of about 1928. I had first used these in 1935 when I built a short wave radio at the age of ten, and have had them since. I repaired the headphones and found a transformer; not, regrettably a gec one but a contemporary one at least. I got the reaction part of the circuit to work and now I have a model GECoPHONE of 1924 behaving very well indeed after many hours spent restoring it.
The power supplies originally were an 80 - 100 volt high tension battery plus a low tension 2 volt accumulator lead-acid battery in a glass container. I now use a solid state circuit 80 volt power supply from the mains and two 1½ volt cells in series for low tension. There is a rheostat in the radio to reduce this to 2 volts.
The GECoPHONE BC 3250 appears to be quite rare, as it was soon superseded by a newer model in a vertical mahogany cabinet with doors and with the valves and coils hidden behind the front panela much neater proposition.
The wireless is a detector with one stage of audio amplification, model O-V-I, using two valves. The radio signal was picked up on a copper wire aerial mounted as high as possible. The resulting audio signal was fed to the audio amplifier stage which could operate two or more sets of headphones.
It must be remembered that in 1924 there was only a limited number of commercial radio stations on the air with some form of entertainment and weather forecasts, and the hours of transmission were limited. Of course wireless traffic was increasing rapidly between ships and shore stations, mainly in Morse and strictly business.
The wave length coverage of this model was about the same as today's medium and long wave bands using plug-in coils. At the time the long waves were considered more favourable for long distance coverage. With careful use of the reaction control long distance stations are easily picked up.
Many benevolent sources at that time presented wireless sets to ships, remote lighthouses, etc, and this one was presented to the Daunt Lightship by the Daily News and The Star Fund as indicated by the engraved brass plaque on the left hand side of the set.
Such radios must have been a boon to people like the crew of the Daunt Rock Lightship in 1927, opening up a new expanding world to them.
© J. G. Trevor Owen, 1997