View single post by Slider2732
 Posted: Nov 5th, 2008 10:54 AM
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Slider2732

 

Joined: Mar 3rd, 2008
Location: Muskogee, Oklahoma USA
Posts: 349
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 Crystal circuits I too am not that familiar with unfortunately. I have always been put off by the need to have a good Ground connection, the wire that should go to perhaps metal household plumbing or metal heating system of the house. The aerial typically needs to be quite some length too, to pick up stations...2 metres and more. Apparently a long wire can run from a handheld crystal circuit and touch a concrete floor as the Ground connection, but with all being able to be replaced by 1x AA battery for a conventional receiver, it just all passed me by.

They do work, but do need a correct earphone. The ones for cassette recorders etc need power to work, however there's no battery in a crystal circuit.

Such work is very important in my opinion, especially within ITC. Stray pick ups of strong signals might give false results in sweep radio circuits etc, if someone were to use a germanium diode in place of a regular one. On altering a Casio home keyboard earlier this year to get some better sounds out of it, I inadvertantly created a radio circuit and picked up a local channel !  Quite funny, but showed that radio circuits need not be designed and can be the consequence of some components interacting with others.


Just had a look at this page: http://www.crystalradio.net/howitworks/index.shtml
It has the fundamentals of crystal radio operation and while quite basic, teaches the basics. Quite often ITC seems like High school physics lessons. Only later do I think such things might be useful and wish i'd paid a little more attention at the time lol