Re: Coherer experiments

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "davep by way of Terry Fritz <twftesla-at-uswest-dot-net>" <davep-at-quik-dot-com>

Random thoughts re coherers (from reading olde wireless books):

	As noted, all manner of things were tried.  Experiment.

	One quote:
		Any change can affect the quality of the product.
		as simple a thing as using a new file, or cleaning
		an old one can affect the results 

	A coherer, one 'fired' stays conducting (low resistance).
	It needs to be 'tapped back' to 'decohere' to receive a
	second signal.  Typically,  (i think someone mentioned this?)
	as the coherer cohered, it activated a relay, which ALSo
	'tapped' the coherer to open the circuit.
	(The performance is analogous to a thyratron, or an SCR..)

	On CW it would simply conduct continuously, unless the
	tapping back forced it to switch on and off.

	At the time (and, maybe, to this day?) No One Knew HOW
	(on a laws of physics basis) they worked.  Much speculation,
	but not worked out then.  (Possibly (I SAID _possibly_) a
	form of funny shaped MOV....)

	In the early days of wireless it WAS broadcast power.  (with
	an exception i will mention...)  What was heard was based on
	the energy arriving...  The coherer could be used in this mode,
	OR  (for code work...) it could be used to make an 'amplifier'
	by tripping the sensitive relay, energized from local power.

	At some point in the mid 30's there were investigations of using
	coherers in lighting detection studies, on power line
	protection studies...

	best
	dwp