On 2009-02-06, wrote:
On Thu, 5 Feb 2009 09:23:58 -0500, "Proctologically Violated©®"
wrote:

[ ... ]

Funny that radios and ham operators would use this, as my understanding was
these things eventually became illegal to use or sumpn, because of the
massive radio interference they generated, due to the 60 hz arcing of the
contacts.

Not in a properly designed radio.

I could see a ham perhaps sending signals with this vibrator ditty, but
having a helluva time receiving stuff.

But if they were used in car radios as well, then mebbe this is not in fact
an issue.

But iirc, there was sumpn about them being illegal due to the generated
interference.
In radio use they were always in a CAN - and they ran 115hz.

Except one which I used to generate 20 Hz ring signals for a
small dial telephone exchange. The can was larger in diameter than a
beer can of the time, and the vibrator had a big horseshoe shaped weight
on the vibrating tongue to lower the frequency.

Also -- the whole assembly in the can was packaged in foam
rubber to minimize the acoustical noise transmitted to the car's frame.

They
died out not due to legislation, but due to technology changes, The
transistor killed the vibrator inverter DEAD in a matter of a very few
years.

Exactly. I wonder how long that sealed in foam rubber would
have lasted. I do know that the things were plugged into 4-pin tube
sockets (with a set of fingers to make grounding connection to the can
to control RFI.

This was one of the first uses of transistors in automobile
radios -- to generate the higher voltage that the tube plates needed.
And the power lead in from the car's circuit was connected to one side
of a very thin printed circuit board, with the other side firmly
grounded to bypass HV spikes in the power from the car's electrical
system. (I guess that a sufficiently high spike voltage would arc over
the edge of the circuit board, but mostly it acted as a high frequency
and low inductance capacitor. :-)

Enjoy,
DoN.

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