Flights Of Fancy AM receiver wiring

Question

I've got a Flights of Fancy AM crystal receiver that has been in the attic for years. I want to put it together but can't find the instruction booklet. Is anyone familiar with this receiver? Does anyone know how it should be wired?

I just add a schematic of how it was wired about 10 years ago. There is no capacitor anywhere. The last wrap of the coil wire is about 3" long and just hangs in the air.

Using a 15ft long antenna and sweeping across the 5" length of coil I get only two stations. Any ideas what would improve it?

I would appreciate any thoughts on my latest schematic below. I've also added a resistor.

Thanks, henrylr

Answer 1

Am going out on a limb here (cannot find a schematic), and you should too, to attach one end of the antenna wire. In the photos for "Flights of Fancy", I see a tapped inductor, an earpiece audio transducer. The diode is small and not easily visible. I do not see a capacitor. Nevertheless, an inductor, diode and headphone are minimum components (in addition to antenna and ground). Some possible schematics:

^{simulate this circuit – Schematic created using CircuitLab}

The antenna is a long wire whose far end is not connected, but is ideally up high. Ever seen AM antenna site with multiple towers extending 70 M up? That's an ideal length (but less will still give results). The diode is attached to the coil somewhere along its length to give best volume. Diode direction does not matter. The speaker must be a coil-of-wire type that reacts with a permanent magnet. Modern headphones are of the correct type, but have too-low impedance to give much volume. Old high-impedance headphones are ideal.
Note that a ground connection is very necessary. A connection to metallic plumbing distribution is fine but any plastic parts along the path to outside ground will reduce effectiveness. Metal fencing usually has long runs that make it attractive for ground. On my wall outlets, a single screw attaches the plastic cover plate - that's a decent ground as well, because all my boxes hidden in the wall are grounded metal. However, a curious child might try plugging into the outlet resulting in disaster.

Answer 2

The Wikipedia entry of "Crystal radio" shows several possible schematics. A good earth ground, not through a plastic water pipe, is important. Note that the galena crystal is picky about where the "cat's whisker" is set on it, you have to adjust it's placement by getting the highest audio volume.