Re: [time-nuts] LED instead of discharge lamp for Rb vapor cell standards

2018-02-21 Thread Bob kb8tq
Hi There are a number of papers on LED / Laser excitation of Rb cells (and other gas cells). They go back quite a ways. The gotcha (as pointed out in PHK’s post) is that you need to stabilize the LED source. Doing that is a bit complex. Doing that so that the result beats a gas lamp is a bit

Re: [time-nuts] LED instead of discharge lamp for Rb vapor cell standards

2018-02-21 Thread Poul-Henning Kamp
In message <20180221184928.1c9b4c3a4d2e762970b5b...@kinali.ch>, Attila Kinali w rites: >So the Rb85 "notch" filter might not get rid of all the unwanted light >and some of this might depopulate the excited state of the Rb87 >that are in the RF cavity. I have a hard time seeing how you

[time-nuts] The "NAKED" 5065A optical unit

2018-02-21 Thread cdelect
Attila, The Child and oven windings were destroyed pulling the oven cylinders out of the potting. I suppose you could replicate them and try to repot but I'm never going to try! Cheers, Corby ___ time-nuts mailing list -- time-nuts@febo.com To

Re: [time-nuts] LED instead of discharge lamp for Rb vapor cell standards

2018-02-21 Thread paul swed
Attila I haven't tried that and I suspect the lines are important because that establishes the reference. Now I would also suggest that an experiment like you suggest be tried on a FRS-XXX cheapy Rb. Easily dis-assembled and can be re-assembled back with the lamp. No harm. Paul WB8TSL On Wed, Feb

[time-nuts] LED instead of discharge lamp for Rb vapor cell standards

2018-02-21 Thread Attila Kinali
Moin, Has anyone ever tried using a LED instead of a discharge lamp for Rb standards? There are quite a few and very cheap 780nm IR LEDs available. They usually have a line width in the order of 20nm to 50nm (FWHM). This means that they still need the Rb85 filter, but they would not produce all

Re: [time-nuts] The "NAKED" 5065A optical unit

2018-02-21 Thread Attila Kinali
On Wed, 21 Feb 2018 15:37:53 + "Poul-Henning Kamp" wrote: > I was talking about driving the single-transistor UHF generator which > ionizes the Rb in the lamp, so far I have not even established if > this voltage affects the HP5065 performance in the first place.

Re: [time-nuts] The "NAKED" 5065A optical unit

2018-02-21 Thread Poul-Henning Kamp
In message <20180221163511.b8d6eec26415fe16e66e4...@kinali.ch>, Attila Kinali w rites: >On Tue, 20 Feb 2018 09:36:49 -0700 >Mark Goldberg wrote: > >> I don't know anything about these devices, but for TCXOs, the power supply >> noise significantly affects the

Re: [time-nuts] The "NAKED" 5065A optical unit

2018-02-21 Thread Scott McGrath
WRT Rb on the envelope, the 5065A has a built in 'cold trap' to recover the Rb into the reservoir, Instructions on use are in the manual Content by Scott Typos by Siri On Feb 21, 2018, at 10:33 AM, Attila Kinali wrote: On Tue, 20 Feb 2018 10:03:20 -0800

Re: [time-nuts] The "NAKED" 5065A optical unit

2018-02-21 Thread Attila Kinali
On Tue, 20 Feb 2018 09:36:49 -0700 Mark Goldberg wrote: > I don't know anything about these devices, but for TCXOs, the power supply > noise significantly affects the phase noise of the output. An LM317 is not > well specified for noise and I expect is is orders of

Re: [time-nuts] The "NAKED" 5065A optical unit

2018-02-21 Thread Attila Kinali
On Tue, 20 Feb 2018 10:03:20 -0800 wrote: > You do NOT want to take one apart to this level! > > It's never going to operate again. Why not? Is there something you had to break to open it up this far? Attila Kinali -- It is upon moral qualities that