[time-nuts] Re: Sparkfun lists SA.35m

[ew]

A couple of years back, we started to explore using Laser Diode with a FRK. Started by looking at shorter time constant for the loop and found that 0.055 seconds gave best AV. Longer time constant for Laser control. Also using external reference for tuning. Using HP 70 000 Optical Plug in to characterize Lasers. Decided we did not need it, having to many FRK / M100 with good lamps , age, to many projects and most likely no interest by time-nuts even though there  are quite a few dead units out there. I am convinced a team effort not only talk but hardware would make it possible. With laser it would not be needed but a Filter with good lamp and short time constant is still on the list. Have a unit disassembled, but my left eye mecular hole is a problem. Did some soldering today, 30 minutes, that should have taken 1 minute.                       Bert Kehren    In a message dated 4/3/2021 11:09:02 AM Eastern Standard Time, magnus at rubidium.se writes: 
Hi,

What you do is that you servo the semicondoctor laser to the transition,
as you do that with sufficiently narrow laser you can utilize the CBT
mode operation which has additional benefit rather than just replacing
the rubidium lamp with a semiconductor laser. Getting a laser in 780 nm
range isn't all that hard in itself, I have a bag of those lying around
for experimentation, not that they are good enough for this, but well,
it would be fun.

Cheers,
Magnus

On 2021-04-03 16:51, Dana Whitlow wrote:
> I knew about the use of the VCSEL, but I'd bet a good dinner that it's not a
> Rubidium laser!  Last I heard, none of the elements in that corner of the
> periodic table were semiconductors, and it's hard to imagine a vapor-based
> VCSEL.
>
> Dana
>
>
> On Sat, Apr 3, 2021 at 7:31 AM Lux, Jim <jim at luxfamily.com> wrote:
>
>> On 4/3/21 4:22 AM, Dana Whitlow wrote:
>>> "rubidium laser" ???
>>>
>>> Dana
>> I don't know about the MAC, but the CSAC uses a VCSEL to shine through
>> the gas cell.
>>
>> The MAC is a pretty big thing compared to the CSAC - it's in the usual
>> 2x2" package and draws 5-8W (after warmup)
>>
>>> On Sat, Apr 3, 2021 at 2:15 AM Poul-Henning Kamp <phk at phk.freebsd.dk>
>> wrote:
>>>> I know it's not a particular outstanding atomic clock, but I was still
>>>> surprised to see that Sparkfun lists the SA.35m for $1995...
>>>>
>>>>Â  Â  Â  Â  Â  https://www.sparkfun.com/products/14830
>>>>
>>>> Not in stock though...
>>>>
>>>> --
>>>> Poul-Henning Kamp      | UNIX since Zilog Zeus 3.20
>>>> phk at FreeBSD.ORGÂ  Â  Â  Â  | TCP/IP since RFC 956
>>>> FreeBSD committer      | BSD since 4.3-tahoe
>>>> Never attribute to malice what can adequately be explained by
>> incompetence.
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