The AM Forum

Well here is a thought I had this morning after receiving my latest Ebay purchase....  I spotted this 7290 kc crystal for $3.99.... thought it might fall into the local AM ragchew frequency so I sprung for it.

Photo shows it at arrival, I haven't opened it yet because I got to thinking that the air inside the sealed can is from 1952. 

I don't even know what the crystal holder type is or whether or not it will even be useable but the concept of having trapped air from 7 years after I was born available to get a "whiff" of intrigues me.  8 years before I got my novice license as well....

Shouldn't there be a "ceremony" of some kind?  How have others handled this?

73, Tom

That is so neat! If there was a way to analyze that air inside, I'd wager that the CO2 level in that air is higher than what it is now. I am not old enough to remember 1952, but I remember 1960...things were pretty dirty back then. Remember I think, 6 stacks from Con Edison putting a sooty cloud over Detroit.

It will be curious to see what the holder type is, and how close to 7290 it is at.

Jim
Wd5JKO

Al's museum will pay you dearly for it.  Regardless, as 'JKO mentions, the xtal plant air at that time probably wasn't pure mountain pristine.  Of course the can's internal lining and other packing material have contaminated what air is in there.  It may even be partially gettered into a vacuum. The sum of partial pressures can be estimated by the can mid-girth ratio of old to new, a well known measurement in certain circles. *

The value of an unopened xtal can vastly improves if you join "Vintage & Retro Xtal's Anonymous," an exalted world-wide save the xtal type of society.  Their yearly auctions I've heard are vibrant and shattering in the big money circuit.

Girth ratio value.

G.         Al  Value

1.0        Better give it to the dog.  Not suitable for transport on society jets.
0.99      Hmm, might hold on to it for awhile.
0.98      10 years old at STP (atmos. standard temp. & pres.)
0.97      25 years old at STP
0.95      50 years old.  Prime ordinary trading cutoff date.
0.93      70 years old.  wonderful war surplus peak.
0.92      Usually larger than standard can.  Xstals holders larger. Rare and Al value high.
0.90      Implosion limit for typical can construction at the time.  Any found, -very rare.

Do not be confused by 1/Av, a ruse for the unwary.

Could have the bouquet of nuclear fallout. I hear it smells like electricity. The IVY and MIKE shots were in '52. Be cool to give a preliminary sniff with the old Victoreen.

RSWL........................

Pandora's box is open.  I got tired of looking at the can so I got the opener out.  Particularly after the fellow I purchased it from said he had "hundreds of pounds" of the canned crystals..... ancient war surplus.

Picture identifies the components and brings up a question... the crystal was well packed inside a cardboard box and surrounded with a 1 oz of silica gel.  Inside the box was the crystal wrapped in a relatively flexible wax impregnated paper or cloth sheet (green).

The top of the crystal is clearly marked 7290 C but the side says "140.94 MC" and under that "CR-1B/AR" then "CL".  The other side is rubber stamped "NAS QP OH 4 51".

I haven't run it through my crystal frequency checker yet but will tonight.

I will have to make an adapter to fit my Viking II crystal sockets.

It appears to have been designed and used as a VHF crystal but the equipment it was used in is unknown to me. Still fun to see what those '52 tax dollars wrought.

Tom

I think the CR-1B/AR refers to the type of case and pins.
Here's more in those cases:
https://picclick.com/Two-CR-1B-AR-Amateur-Ham-radio-Crystals-NOS-112381978071.html

Using typical crystal multiples, 140.94 comes out with a fundamental of 7.83 MHz.

I think I have several military crystals still sealed in heavy paper packets. This is common stuff at flea markets.

Here are some CR1-A's which I would presume are very similar. They are great sources for quartz blanks to grind. And the blanks normally will fit into one of the several types of FT-243 packages. So open the crystal and transfer the blank into an FT-243 holder. They open in one of 3 or 4 methods.

Did you smell the bouquet from the can when opened?

Yes, of course!  It smelled  like all other war surplus packages I have ever opened!  Mildew overtones.

Tom

I swear this and other fragrances could be bottled and sold. Aromatherapy. Restoring the old radio smell to an old wood radio after it has been rebuilt and the cabinet refinished. Deodorant. ?!?

It is a hard smell to capture, like a new car smell. I think if you put a bunch of old paper capacitors in a damp cardboard box and keep the whole Gilgamesh in a cool dark place for ten years you could achieve the goal?

Way ahead of you:
http://soldersmoke.blogspot.com/2009/03/solder-smoke-cologne-new.html