What the devil kinda radio is this?
 

My boss here at work found this bugger in his attic, belonged to his uncle many MANY years ago.

Any ideas? :dunno:

http://i176.photobucket.com/albums/w...CIMG0133-1.jpg

http://i176.photobucket.com/albums/w...CIMG0134-1.jpg

http://i176.photobucket.com/albums/w...CIMG0135-1.jpg

That's a battery operated radio from the early '20's. I don't recognize the maker; but, maybe someone will chime in.

That's a keeper! I recognize the face and some of the internal components from pictures that I have seen before. I am at work now but I have an antique radio site bookmarked at home that has radios that look like yours. I will find it and post the link for you unless someone else does so first.

This is most likely a "homebrew" or homemade set from the very early twenties. All of the parts were available separately then and many guys made their own sets. The tube is very early, with its brass base, short pins, and evacuation tip on top. Don't try to test the tube or do anything to it. They are more and more rare and collectible, as is the whole set, even moreso if all is together with the tube as it appears to be. That tube is probably a WD-11. May have info marked on the base. Tube is valuable even if not good, but may be good. All I would do with this set is dust it off carefully and then clean with damp cloths. The owner may want to keep it as a family heirloom. You can get more opinions on it by posting your query with pictures over on Antique Radio Forum, the Antique Radio Discussions division.

Reece

That looks like what 1/3 of my neutrodyne radio might look like if you removed the other 2/3! :D I think yours is from the very early (first half) of the 1920s, or possibly even a little earlier. If earlier, it predates the first-ever commercial radio station broadcast! Very cool find; keep it intact!

My vote is for homebrew as well...or at least some rudmentary form of a kit. Neat find!

It may be an equivalent tube, but I think genuine WD-11's have longer pins.


--Bob

Definitely a homebrew. Although I have a considerable herd of old radios, I could never bring myself to invest in a "Primitive" style radio such as that one.

In fact, I've divested myself of two of the three I had. The last one stays because although it's a primitive, it's a later model, that at least has some grace in the construction.

It's a keeper, Tim!:thmbsp:

Yep, the short pinned wd-11s were popular in homebrew kits at that time. Check the inside of the wooden lid-I've found a few log charts faintly scrawled in pencil before. Great find!

Yeah, I'd vote for homebrew...An' that Tooob is VERY valuable !

It's a piece of radio history and ought to just have its face washed a little and preserved the way it is. It may not look like much, but sets like these are beautiful to me because of what they represent. Some kid saved up to get the parts and built this somewhere almost ninety years ago and climbed on the roof and up in a tree to string his antenna, and then listened to voices and music out of the air, for the first time. It was magic to him and his family, and it still is to me.

Reece

That's a rare bit of history. Don't junk it. Can you do a continuity check?

Well said Reece.

A little OT; but, does anyone remember the PBS documentary "Empire of the Air" that came out in the early '90's. It may still be available on DVD. There's a lot of good information on that film about the early days of radio.

Really neat old timer. Wonder if you could figure out the power requirements and get it up and running? Cabinet looks like it would be easy to restore with the most difficult being the warped top and would clean up nicely.

The WD-11 tube is very delicate. Filament voltage is only 1.1 volts, less than a single flashlight battery, or dry cell back in the day (filament was lit through a rheostat on the radio to compensate for battery running down.) The attached shows the basing diagram and tube characteristics. I wouldn't use an ohmmeter on it directly because you don't know what voltage it might impress on the filament. Safest way would be to put a resistor of a few hundred ohms in series with the ohmmeter and check the filament that way. Any reading at all would mean you had continuity. At the same time you could check between the other elements to make sure none of them was shorted to another.

If you can clean the set up and then draw the circuit diagram, we could advise how to try it out. Should be pretty simple. Battery requirements should be 1.5 volt D cell for the filament, and three 9-volt batteries snapped together to yield 27 volts for plate.

Reece

http://www.nj7p.org/Tube4.php?tube=wd11

It's definately a homebrew. The tube is a WD-12. The WD-11 was a long pin only tube. Teh WD-12 is basically a wd-11 mounted in a UV style base. Usefull for folks wanting to switch to dry cell operation of there uv-201a equiped sets.

THe tube is not as valuable as a brass based wd11 because even though they are more rare they are not as in big demand. The can be had for about $60.

Steve

would a multi meter really put out the current to blow a tube filament ?

That would make a great restoration project (a challenging one at that).

That particular tube, yes, it could. Some of the battery powered VOMs use a 9V battery, for example.

I think the series resistance of the meter and the meter movement would limit the current to far less than a quarter amp.

A VOM only puts out current when it is measuring resistance. Since the circuit must be de-energized when measuring resistance, and you need a source of current in order to measure the voltage drop across the resistor, the VOM/VTVM/DVM/DMM provides it.

The amount of current used is miniscule, and it's highly unlikely you could cause damage with it, unless you're trying to measure continuity through your PC's chipsets. The battery used to power the multimeter is NOT passing that full voltage through the probes.