An interesting old Coil

[unrealdave]

Dave, I expect to see you wearing a kilt in the near future

Possibly in the colours of the Third Foot and Mouth

Aye - that'll be me

[AlanBeckett]

And then there were - I've lost count

Anyway, this turned up and looked Interesting.

                           

The LW/MW Switch is built in. Presumably you had to reach over the top of your home-built Set to operate it, unless you mounted it horizontally and let the Knob poke through the Front Panel. 
In the usual manner at this vintage MW is labelled Short Wave.

Working out the Connections was a bit tricky so I finished up disconnecting the Wires. After that it was all very logical, even normal.

       

Despite the protestations on the Box I've never heard of them, and I couldn't find much on the net.

Despite the mild Weather Winter must surely come shortly and make the Garage uninhabitable. To that end I'm setting up for some indoor playing with these old Coils. I've got one more to go at - more later.

Alan 

[unrealdave]

I've got one very similar to this only its a plug in coil.  The base is Colvern but the coil says 'TUNEWELL' and the maker is Turner & Co, New Southgate N11.  When I get a mo I will check the readings to see if it is the same. 

[pwdrive]

Millgate might be the Chorlton Metal Co ?

http://www.americanradiohistory.com/hd2/...horlton%22

Lawrence.

[AlanBeckett]

Dave,

If you've got the energy to flog through the rest of this Thread you'll find more info on Colvern Coils and Bases.
Is the Knob a Switch or just to help with pulling it out of the Base

Interesting Lawrence. It's certainly the same Name but ......

Alan

[Yorkie]

Millgate might be the Chorlton Metal Co ?

http://www.americanradiohistory.com/hd2/...horlton%22

Lawrence.

What amazes me when looking at old magazines from the 30s is just how costly everything was by today’s standards. For example, in the text at the above link there's reference to a Millgate 120V HT batters at 11 shillings (55p), which the text says represents 'very good value for money' as it may well have been by the standards of the day, but when adjusted for inflation equates to £34.50p. Heck, you can buy a DAB radio for much less than that now.

http://inflation.stephenmorley.org/

I don't know how long a radio would have run for on an HT battery, but I can well imagine that radios weren't just turned on and left on for hours on end,but that people had an eye to running costs. This was, after all, during the 'depression' era.

When you look at those coils, and how much time and effort went into designing and producing them, it's clear that they were quality items requiring a lot of labour to assemble them. I dare say too, that the production costs of the Bakelite formers were high - tooling etc. Most of the firms who produced this stuff seem to have been small outfits who wouldn't get the benefits of economies of scale.

[AlanBeckett]

For example, in the text at the above link there's reference to a Millgate 120V HT batters at 11 shillings (55p), which the text says represents 'very good value for money' as it may well have been by the standards of the day, but when adjusted for inflation equates to £34.50p. ale.[/size][/font][/color]

I think that's entirely the point David.
When I was a lad with no Mains Electricity my Parents only turned on the Wireless when they wanted it.
The HT and GB Batteries lasted a long time, but the 'Accumulator' was charged every Week.

Alan

[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

[AlanBeckett]

Is this the same Company, many a long year on - http://www.nexusinds.com/bg/uk
The Logo and Location are wrong, but .......

Alan

[pwdrive]

That looks worth it Alan, I like the coil, your having better luck reverse engineering than I am with that French recepteur I'm trying to extract a schematic from, no ID on any of the coils and it's all a bit tight to see.

Lawrence