1910 Design Crystal Radio Set - Everything Old Becomes New Again

[W1UJR]

I've been really absent from the radio scene since last summer, the biz has kept me busy, have missed most of the hamfests, and rarely operate on the air.
So it was with delight that I was at a ham radio meet last Saturday near Bangor, Maine with the YL Nancy and Larry NE1S, beautiful day.
We arrived and parked the car, I was really pleased at the turnout and the weather, a good number of folks in the parking lot.
No sooner than I had got out of the car, I noted a fellow directly in back of us with an old looking set.
The loose coupler was a dead giveaway something was very interesting here.
I walked across the aisle and could not believe my eyes.
Here, before me, was either a very nice replica or original 1910 crystal set, complete with loose coupler, an enclosed Murdock air variable cap, and some nice porcelain knife switches or a late day model made up nicely of NOS parts.
Needless to say I snapped it up, this artifact of the past, not often one comes across such a nice home made crystal radio receiver, designed before the days of vacuum tubes.

My first ham radio meet of the year and I stumble across this, great day.
Stunning day, the bright blue sky and bright green foliage, and great company, only added to the fun.

Complete at http://www.w1ujr.net/bruce's_bench_2011.htm

[WQ9E]

A beautiful piece Bruce, thanks for sharing!  I am glad it found a great home.

[WU2D]

Very nice setup Bruce! Now you are ready for long wave spark transmissions and weird whistlers! I built a loose coupler in high school and still have it up on the shelf.

[W1UJR]

I might have to pick your brain on this one Mike, can't get a sound out of her.
Guess I need to check coil continuity first, the owner, a reputable fellow, said it did play.
Many things to adjust, so sure its me.

[WD8BIL]

Is that a whiskered diode, Bruce?

If so.... patience is the key. Searching for that sweet spot can take time but once you find it half the battle is over.

[AJ1G]

Didn't those old sets sometimes have a buzzer circuit to generate broadband RF hash to allow you to find the "sweet spot" on the crystal?

I remember futzing around with the cat whisker on a Cub Scout crystal radio kit when i was a kid.  As I recall, it was pretty tricky...

[W1UJR]

Good suggestions guys!
Yes Bud it does have a cat whisker type diode.
I'll need to play around with it a bit more, thought about just using a geranium diode for testing purposes, then switching over to the cat's whisker once I get the hang of it. With the loose coupler and it's settings, and the two variable caps, there is a bit to tweak.

Currently I'm out in Phoenix, AZ for a BMW/Mini/Volvo tech conference, so will be a bit before I am back.
Phoenix in June, go figure!
First trip in recent memory where I did not take even a shortwave radio along...must be getting old.

I'll report back our findings.

[Carl WA1KPD]

Or you could cheat and hide a 1N34a or, even better yet a radar diode underneath the set. Not that I would ever do such a thing......

[W1UJR]

Your on the right track as always OM.
At least until I get used to the other controls.
Nothing like "tickling the whisker". :-)

[k4kyv]

You can order cat-whisker type crystals and holders here.

http://www.xtalman.com/detectors.html


Antique Electronic Supply in Tempe AZ used to also sell them, but I see they are not listed any more. AES used to sell a lot of stuff for restoring antique radios, but I notice lately they are catering more to the electric guitar amplifier crowd and audiophool stuff. Even though I have ordered from them within the past year, I no longer get their catalogue, which used to be a work of art in itself. I do occasionally get sales sheets and "mini-catalogues", but they are almost entirely devoted to guitar amplifier stuff.

They still have a fairly good selection of tubes, but even that isn't what it used to be. The last time I ordered some tubes, the ones that came were made in Korea, not n.o.s. American-made, and more often when you click on a tube type that is on their list, it comes up "out of stock". And prices tend to be on the increase, too. The components they have for sale are increasingly the modern variety, the exact same thing you could find at your local electronics parts store, or order from Digi-Key.

I wonder if their long-time sources from all over the country (estates, private collections, etc) are about depleted, or if, because of the "economy", there is less interest in antique radio restoration and/or less disposable income for purchasing this kind of stuff. Probably both.

More reason to never throw anything away that is still good, even though you may have had it around for years and never found a use for it.

[AJ1G]

Bruce - if you can access the Internet, you have access to a LOT of receivers worldwide, check out globaltuners.com....

If you want to listen to 75 meters in New England, there are a pair of receivers in NW CT on the list.

I would say that I have just thrown this thread off topic about as far as one could ever imagine..by a time warp of about 101 years!

[Knightt150]

Remember these receivers work on micro mills so the slitest corrosion stops the current flow.

John W9BFO

[Todd, KA1KAQ]

Since the Loose Coupler a.k.a. Receiving Transformer didn't really come into use until the mid 'teens and the two variables weren't made until the '20s, I'd guess it was a later replica based on a '20s design. The lack of any patina due to age would appear to support this. Chelsea didn't start business until 1922, and Murdock didn't use the clear plastic body until the '20s, earlier versions utilized a hard rubber casing similar to some of the early horn speakers. The coupler doesn't show any tags or other identification so it could be homemade. If you remove it from the other board, it might reveal a label on bottom. Looks similar to an Arlington design, but different in other ways. Those porcelain switches were still being sold in the '60s-'70s, I remember purchasing one at the local hardware store along with some dry cell batteries for a science project.

At worst, you've got $100 or better in parts and era-specific components for future use. Probably more than the hamfest price and handy to have on hand. But it would be a shame to tear apart a nice little display piece like that. Crystal sets are a lot of fun to play with. Even visitors with little interest in radio were always amazed by a demonstration of a little wooden crystal set that sat on the fireplace mantle at the VT house, powered purely by the invisible radio waves transmitted by the station they were hearing. No electrical plug, no batteries, just magic.

[WU2D]

Bruce, the tapped end is the secondary and the slider side is the primary connected to the 100 ft antenna and ground. To hear an AM station you will need only about 1/2 inch of slider coil. That's right, the big coil is about useless that high in frequency. Put a 365 pF variable on the secondary side with the cats whisker, the fixed cap and the phones and you should be able to tune the BCB.

Mike WU2D