[time-nuts] the end of light bulbs as we know it was Re: Safe power-up. was (Solartron 7075 ...)

Chris Albertson albertson.chris at gmail.com
Wed Oct 12 01:00:26 EDT 2011


Another connection from Time Nuts to incandescent light bulbs is the early
HP Wien bridge oscillators.  They used the light bulb for amplitude
stabilization. This light bulb stabilized oscillator is what put the HP
company on the map.

There was a time when these oscillators where the best available.  I have
one of these and it still produces a good distortion free signal for testing
and measurement of audio gear.

On Tue, Oct 11, 2011 at 6:06 PM, John Howell <j at howell61.f9.co.uk> wrote:

> Sorry Tom, (again!),
>
> Just as significant is the radiation from compact fluorescent lamps, many
> radiate strongly in the 50-60KHz region from their SMPSs. This has been the
> reason for failure of several clocks I am aware of that are tuned to
> radiocode transmissions on 60KHz.
>
> John H.
>
> On 12 Oct 2011, at 01:28, Gerald Molenkamp wrote:
>
> > Hi All,
> >
> > Sorry Tom, worth a mention.
> >
> > I replaced all of my down lights after my Kids wanted us to contribute
> > to lowering our carbon footprint. On the positive side, moving to LEDs
> > will provide savings around $107/year in electricity charges.
> >
> >
> >
> > Now to the negative part , noise floor from around 21MHz to well over
> > 500MHz raised to a signal strength 5 to 6 across mid to upper HF / lower
> > VHF to upper UHF with them switched on, otherwise my noise floor is
> > Zero.
> >
> > Lower VHF  to UHF SSB/FM low level signal work is now not possible when
> > LEDs are on, mostly at night when we enjoy the hobby.
> >
> > The net effect of dirty LED lighting has long term issues with sensitive
> > receivers.
> >
> > Regards
> >
> > Gerald
> >
> > VK3GJM
> >
> >
> >
> >
> >
> >
> > There is one angle that was not covered, but which is relevant (at least
> > to those of us using any LF or HF time receivers).
> >
> > Over the weekend I bought my first LED bulb.  It was on sale and I
> > wanted to see how it worked.  On the package it gave a warning that it
> > could interfere with HF communications in the 0.45 - 30 MHz range and to
> > not install it near any maritime emergency communications equipment.
> >
> > Peter
> >
> >
> > On 10/11/2011 6:56 PM, Tom Van Baak wrote:
> >> This thread is wonderful, nostalgic, technical, futuristic, and
> >> appropriate for someone's list. But not time-nuts. Please stop it now.
> >
> >> Don't reply.
> >>
> >> /tvb
> >
> >
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-- 

Chris Albertson
Redondo Beach, California



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