21-12-2015, 10:03 PM
(This post was last modified: 21-12-2015, 10:04 PM by AlanBeckett.)
And finally(?) for this year .....
This one came attached to a Home-built Wireless.
As it was all of a couple of Miles from me, and contained some interesting Components apart from the Coil, I decided I might as well bid. I wasn't disappointed and got it for £24.
It contains 4 Valves, one sadly with no Filament, Valveholders, Tuning Capacitor, Reaction Capacitor, Filament Rheostat, Switch, Grid Leak assembly, two LF (Inter-valve) Transformers and the all important Coil. There is also the Case.
It wasn't very easy to examine the Coil in-situ. About all I could make out was the name 'British General'. There are references to the Company on the Radio Museum Website - http://www.radiomuseum.org/dsp_herstelle...y_id=11974 - and even a similar Coil, but not the exact one.
I decided that I'd better try to work out the Connections. The Wiring is pretty shambolic but I came up with this:-
It seemed reasonable but I decided the only sensible thing to do was to remove it for a closer look. The only tricky bit was getting one of the Knobs off. It really was stiff and made me very nervous, but it succumbed to some Penetrating Oil and a bit of persuasion. The Shafts appear to be 3/16" Diameter. I can't say I've come across that size before so perhaps it came with its own Knobs originally. The Coil itself was held to the panel by the Shaft Nuts.
Having got it out and cleaned some muck off all was revealed. Each of the Terminals is helpfully Labelled (Cast) as follows:-
REACTION FIXED
EARTH
REACTION MOVING
ANODE
GRID
AERIAL
Further, there are two 'Feet' cast into one end and mounting it that way up all the Printing on the front is the right way up.
Sorry about the Pictures.
The 'Top' Switch, which is 2 Pole, is labelled WAVE CHANGE SWITCH and L, M, S2 and S1.
The 'Bottom' Switch, which is Single Pole, is labelled APERIODIC SWITCH and L, M, S and AG. I guess that's Aerial Coupling and I haven't a clue what AG might mean.
The Switches themselves are quite crude. The Wipers contact the Heads of Screws. Some of the Screw Heads are 'Insulated' with black material, presumably to produce O/C.
A fascinating gadget which must have cost a fortune in its day.
I'll try to work out the internal Circuit.
Alan
This one came attached to a Home-built Wireless.
As it was all of a couple of Miles from me, and contained some interesting Components apart from the Coil, I decided I might as well bid. I wasn't disappointed and got it for £24.
It contains 4 Valves, one sadly with no Filament, Valveholders, Tuning Capacitor, Reaction Capacitor, Filament Rheostat, Switch, Grid Leak assembly, two LF (Inter-valve) Transformers and the all important Coil. There is also the Case.
It wasn't very easy to examine the Coil in-situ. About all I could make out was the name 'British General'. There are references to the Company on the Radio Museum Website - http://www.radiomuseum.org/dsp_herstelle...y_id=11974 - and even a similar Coil, but not the exact one.
I decided that I'd better try to work out the Connections. The Wiring is pretty shambolic but I came up with this:-
It seemed reasonable but I decided the only sensible thing to do was to remove it for a closer look. The only tricky bit was getting one of the Knobs off. It really was stiff and made me very nervous, but it succumbed to some Penetrating Oil and a bit of persuasion. The Shafts appear to be 3/16" Diameter. I can't say I've come across that size before so perhaps it came with its own Knobs originally. The Coil itself was held to the panel by the Shaft Nuts.
Having got it out and cleaned some muck off all was revealed. Each of the Terminals is helpfully Labelled (Cast) as follows:-
REACTION FIXED
EARTH
REACTION MOVING
ANODE
GRID
AERIAL
Further, there are two 'Feet' cast into one end and mounting it that way up all the Printing on the front is the right way up.
Sorry about the Pictures.
The 'Top' Switch, which is 2 Pole, is labelled WAVE CHANGE SWITCH and L, M, S2 and S1.
The 'Bottom' Switch, which is Single Pole, is labelled APERIODIC SWITCH and L, M, S and AG. I guess that's Aerial Coupling and I haven't a clue what AG might mean.
The Switches themselves are quite crude. The Wipers contact the Heads of Screws. Some of the Screw Heads are 'Insulated' with black material, presumably to produce O/C.
A fascinating gadget which must have cost a fortune in its day.
I'll try to work out the internal Circuit.
Alan
