[Milsurplus] [ARC5] mike current

[mac]

Ray,

Well, of course broadcast and other usage passed by long since but  
part of the history and they are still with us.  And telephone  
elements, at least, are still available from various sources.  The  
technology, ancient, old and current gotta still be out there and that  
was what started my musings.

The TCS list a new thing.  Initiated by a gentleman over in the UK.

Dennis D.  W7QHO
Glendale, CA

*****************
On Sep 7, 2011, at 1:25 PM, Ray Fantini wrote:

> They may have been around for over a hundred years but carbon  
> element microphones have not been used in broadcasting for well over  
> fifty years, cannot recall them being used in commercial radio for  
> at least as long and thought the telephone system stopped using them  
> by the seventies or eighties, just try to find a desk set land line  
> phone today! Especially one with real carbon elements.
>
> Also amazed to see the TCS people have their own list, thought the  
> ARC-5 group were specialized.
>
> Ray F
>
> -----Original Message-----
> From: milsurplus-bounces at mailman.qth.net [mailto:milsurplus-bounces at mailman.qth.net 
> ] On Behalf Of mac
> Sent: Wednesday, September 07, 2011 3:55 PM
> To: ARC-5 List; Boat Anchors List; milsurplus at mailman.qth.net List; TCS_Radios at yahoogroups.com
> Subject: Re: [Milsurplus] [ARC5] mike current
>
>
> These things have been around for over 100 years now and there gotta
> be a large body of science and art out there in the technium on the
> composition, manufacture, etc. of just the carbon granules not to
> mention the microphone elements themselves.  I've observed a wide
> variation in the external characteristics (at least) of the elements
> found just in the venerable T-17 not to mention the many thousands of
> telephone, broadcast and other microphone elements that proceeded (and
> followed) it.   Browsed around on Google a bit and didn't find too
> much except for a reference to a 1934 paper that seemed to say that
> the interaction between granules in response to sound pressure is a
> simple make-break action, i.e., the element resistance overall
> decreases with increasing pressure because more granules come into
> contact with each other, not because increased pressure between
> individual granules lowers the resistance of the individual contacts.
> Anyone have a good reference(s) in this area?
>
> Dennis D.  W7QHO
> Glendale, CA
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