Re: Coherer experiments

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

Original poster: "Steve Cook by way of Terry Fritz <twftesla-at-uswest-dot-net>" <Steve-at-g8cyerichmond.freeserve.co.uk>

Marconi experimented with coherers of many different designs, and tried many
different types of material for the filings, eventually using a mixture of
nickel filings and silver filings. I also did many experiments some years
ago, whilst reproducing some of the early radio experiments. Copper was
poor, as was tin. A mix of 1:1 nickel and silver was good, as were fine
carbon granules. The latter were used by David Edward Hughes, the inventor
of amongst other things the ac current balance. I had not thought of trying
them with tesla coils, which is surprising, but I'm certainly going to have
another look at them.
----- Original Message -----
From: Tesla list <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Thursday, March 22, 2001 6:28 PM
Subject: Re: Coherer experiments


> Original poster: "Ed Phillips by way of Terry Fritz <twftesla-at-uswest-dot-net>"
<evp-at-pacbell-dot-net>
>
> Tesla list wrote:
> >
> > Original poster: "Terry Fritz" <twftesla-at-uswest-dot-net>
> >
> > Hi Antonio,
> >
> > Tesla used Coheres in Colorado Springs.  You design is what I have
always
> > heard of too.  However, I think fine nickle filings are usually used.
They
> > detect the sharp initial wildly noisy gap firing when the gaps internal
> > capacitance is suddenly shorted.  I am not sure how they would work with
> > say a CW coil...
> >
> > Cheers,
> >
> >         Terry
>
> Coherer's take around 2 to 10 volts for operation (much less than that
> needed to excite a neon lamp), and I'm sure such a voltage could be
> received in the coherer circuit at a range of several feet.
>
> Ed
>
>
>
>