[time-nuts] R&S XSRM Rubidium

[paul swed]

Ordered a small heat gun today. Has 2 temperatures and I am sure the low is
going to be more then enough. I plan to mount the RB lamp upside down so the
heat from the gun goes upward. The operating temperature normally is about
177 degrees F. So will add in a K thermocouple to monitor temp and then will
gently raise the temp above the 177 region to see if two things can be done.
1) Migrate the RB blob to the center lowest point of the bulb to make it
visually obvious and actually measurable with a micrometer.
2) Boil the blob off and back into the RB atmosphere.
All the while documenting the temperature and time of the process.
I think the biggest risk is actually popping the RB lamp from over preassure
from higher temperatures. So Magnus as you say take it gently. Maybe 225-250
region.
The heat gun should be here in 5-7 days.
Regards
Paul.

On Sun, Jan 23, 2011 at 11:01 PM, paul swed <paulswedb at gmail.com> wrote:

> Hello to the group.
> Well I did bring the RB oven online and indeed the color went from the blue
> to the purple/pinkish color when the oven stabilized at 170-177 degress.
> Thats what I see it moving around at.
> John I agree it doesn't seem to matter what the frequency is. Though my
> oscillators is still cranky to start. Really an issue. And the little RB
> blob moves around. Interestingly when at temp and purple light I can see at
> the center of the ampule window small blobs. Very small. But the area is
> actually a bit dimmer because of them.
> Looks like I need to hunt down a heat gun now. Have to buy one from some
> place.
> So this may go silent for a bit till I get one or find out whats up with
> the oscillator starting.
> Regards
> Paul
>
>
> On Sat, Jan 22, 2011 at 11:19 PM, John Miles <jmiles at pop.net> wrote:
>
>>
>> >
>> > On 01/22/2011 11:31 PM, paul swed wrote:
>> > > Well pretty interesting late afternoon.
>> > > The oscillator works but C-11 definitely is troubled. Additionally a
>> key
>> > > element is an effective ground. Bridge the low side of the ampule to a
>> > > better ground and the oscillator seems to reliably start.
>> > Ignition occurs
>> > > when the oscillator is in the 80-85 MC range. It can tune from
>> > 65 to 130 MC.
>> >
>> > Interesting. I tuned for maximum amplitude. Seemed to work well enough.
>>
>> I've tried peaking a couple of different LPRO-101s for maximum lamp
>> voltage,
>> and in both cases I found that while it was possible to achieve more lamp
>> voltage, the short-term stability ended up being a bit worse.  I need to
>> do
>> some more experiments when I have more time, but my preliminary
>> observation
>> is that peaking the trimmer for maximum output is not necessarily the best
>> strategy.  Hard to say for sure with n=2, though.
>>
>> -- john, KE5FX
>>
>>
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>