crystal radio: the first real free energy device

[pomodoro]

Yes, most use a variable capacitor. Intermediate designs have a variable coupling coil. This unloads your LC tank and let's you separate stations better. I'm getting a few stations at once, the strong stations swamp out the weak ones.

[Pirate88179]

http://www.midnightscience.com/catalog5.html

I found this site with a lot of interesting parts including an $11.00 (US) variable cap.  I can also get a cool pointer knob for about $2.00 more.

They sell galena here if folks want to go that route.

Bill

[Pirate88179]

I see they (the site linked on my above post) also have a coil calculator here:http://www.midnightscience.com/formulas-calculators.html


Bill

[TinselKoala]

Good find! I like those air variable caps. They are quite reasonably priced too. Some of the accessories seem a bit pricey, like the knobs pointers and spacers, but the caps themselves look good. Custom manufactured for the midnightscience shop, too.
And those new-old-stock Galenas, and tickler assemblies, wow.

[Pirate88179]

Thanks. Yes, I have been shopping for the air caps and their price is not bad...plus like $5 shipping but...what can you do?
Did you see where they have a reduction drive on a similar cap?  Then, you can add another reduction drive to that cap to get something like 48:1 for fine tuning.  I just wanted to go this way instead of clipping to a pre selected place on the wound coil.

They do not offer slinky antennas though...they must be behind the times over there, ha ha.

Bill