Your mention of bridges Chris reminds me that the British Post Office developed quartz oscillators in the early 1940s that used filament lamps for amplitude stabilisation in a bridge circuit. Stabilities of ±1 part in 10 to the 8th were achieved.
John H. On 12 Oct 2011, at 06:00, Chris Albertson wrote: > 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 <[email protected]> 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 >>> >>> >>> _______________________________________________ >>> time-nuts mailing list -- [email protected] >>> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>> and follow the instructions there. >> >> >> _______________________________________________ >> time-nuts mailing list -- [email protected] >> To unsubscribe, go to >> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. >> > > > > -- > > Chris Albertson > Redondo Beach, California > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
