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 Post subject: Weekend Find, What Is It? Some Kind Of Crystal Receiver?
PostPosted: Jul Mon 17, 2017 4:35 pm 
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Location: Coos Bay, Oregon
Portland Expo was fun and interesting this last weekend. Lori and I walked maybe ten miles each day, looking for items to display in the museum. This piece caught my eye, since it looked at first like a 1920's crystal detector. There are no names or other idents on it that I could find.

Does anyone know what it is?


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Last edited by startgroove on Jul Tue 18, 2017 1:52 am, edited 1 time in total.
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 Post subject: Re: Weekend Find, What Is It?
PostPosted: Jul Mon 17, 2017 7:30 pm 
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Looks to be a home made crystal set. The tuner is way far gone.


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 Post subject: Re: Weekend Find, What Is It?
PostPosted: Jul Mon 17, 2017 7:42 pm 
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That looks like a balance-weight, not the actual meshing plates (which appear to be fully meshed). If the shaft turns, it's probably OK...


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 Post subject: Re: Weekend Find, What Is It?
PostPosted: Jul Mon 17, 2017 9:40 pm 
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IMHO the lump is a counterweight - if the panel is mounted vertically the weight of the rotor may be sufficient to turn on its own.

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 Post subject: Re: Weekend Find, What Is It?
PostPosted: Jul Mon 17, 2017 10:03 pm 
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Location: Radio Heaven, North Carolina, near Charlotte, 28106-3015
looks like an english crystal set.

.

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 Post subject: Re: Weekend Find, What Is It?
PostPosted: Jul Mon 17, 2017 10:16 pm 
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Location: Carmel, Indiana
Yea, but, where's the coil?

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 Post subject: Re: Weekend Find, What Is It?
PostPosted: Jul Tue 18, 2017 12:15 am 
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Joined: Jun Sun 15, 2014 11:04 pm
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Location: Coos Bay, Oregon
Thanks you guys. I appreciate the information.

BTW, The variable capacitor is not warped or bent. The rotor does not scrape against the stator. The lump is a counter weight of lead, which has some oxidization.

Indiana Radios, that is a good question. I can't see where a coil would mount, and there is none in the box.

Just found out that the crystal is supposed to have a glass tube around it. That part is missing.


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 Post subject: Re: Weekend Find, What Is It?
PostPosted: Jul Tue 18, 2017 12:37 am 
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Location: Radio Heaven, North Carolina, near Charlotte, 28106-3015
maybe the coil went on the front (top) panel, I have a
crystal set like that.

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 Post subject: Re: Weekend Find, What Is It?
PostPosted: Jul Tue 18, 2017 12:42 am 
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Could it be an early variable capacitor designed to be use with an loose coupler?

Maybe someone attempted to turn it into a Crystal set on its own?

-Steve

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 Post subject: Re: Weekend Find, What Is It?
PostPosted: Jul Tue 18, 2017 1:49 am 
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Joined: Jun Sun 15, 2014 11:04 pm
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Location: Coos Bay, Oregon
Ron, That may be. There is a hole in the top panel which is about the size of a mini bulb base. Possibly something plugged into the panel there.

Also, the size and number of plates in the variable capacitor indicate that it's tuning range is low, possibly below the AM band. The plates are about 6" across.

I've looked it over carefully and found two screw holes in the side of the box where something was once mounted. Possibly a label. I'll work up a schematic and post it tomorrow.


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 Post subject: Re: Weekend Find, What Is It? Some Kind Of Crystal Receiver?
PostPosted: Jul Tue 18, 2017 2:25 am 
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Location: Monroe, NC 28112 USA
I think it is part of a wave meter...

Robert


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 Post subject: Re: Weekend Find, What Is It? Some Kind Of Crystal Receiver?
PostPosted: Jul Tue 18, 2017 3:07 am 
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Yes, that was my first impression. Somebody took a wave meter and added a crystal detector to it. You still have to hook it up to a coil.

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 Post subject: Re: Weekend Find, What Is It? Some Kind Of Crystal Receiver?
PostPosted: Jul Tue 18, 2017 2:44 pm 
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Joined: Mar Fri 28, 2008 2:49 pm
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Location: Phoenix, AZ 85085
Robert Lozier wrote:
I think it is part of a wave meter...

Robert


+1
My first thought was wave meter. The coils would have been external to change bands.
Alan


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 Post subject: Re: Weekend Find, What Is It? Some Kind Of Crystal Receiver?
PostPosted: Jul Tue 18, 2017 4:36 pm 
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Location: Santa Rosa, CA
Wavemeter looks like the best idea.

Crystal detector to use with phones for monitoring AM transmission.

Possibly a small light bulb as a "strength" indicator?

Image

Rich


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 Post subject: Re: Weekend Find, What Is It? Some Kind Of Crystal Receiver?
PostPosted: Jul Tue 18, 2017 11:29 pm 
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Joined: Aug Mon 18, 2008 3:17 pm
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Location: Dallas Tx.
Capacitor only tuning xtal sets were used to monitor transmitted signal quality at radio stations.
They could also be used with a variometer, variocoupler, oatbox coil, or loose coupler in the antenna circuit.
Or with a loop antenna.


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 Post subject: Re: Weekend Find, What Is It? Some Kind Of Crystal Receiver?
PostPosted: Jul Wed 19, 2017 3:25 am 
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Joined: Jun Sun 15, 2014 11:04 pm
Posts: 705
Location: Coos Bay, Oregon
I tried to fit a small bayonet style lamp into the socket, but it did not fit. The diameters don't match and there were no slots for the pins on the lamp base.

Here is the schematic.

Below that are pictures of a WW1 crystal receiver (sent to me by an ARF member) which has the same crystal detector and similar design of the dial escutcheons.


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