[time-nuts] HG414A/CH1-78 report

[Magnus Danielson]

On 04/02/2011 06:53 PM, Magnus Danielson wrote:
> Hi!
>
> Yesterday I managed to trim away the unwanted RF from the 5 MHz output.
> I fail to get as good result from the 10 MHz output, but I think it will
> not be as big impact. Will possibly need to handle that. Spectrum
> analyzer helps a lot more than a scope. Happy I invested in a faster
> analog scope.
>
> It is not a stable lock, even if I can se it lock in. I see too much
> noise in it and the status flickers so I think I can blame the lamp
> detection, need to check that. Possibly I will have to do the lamp
> rejuvination trick. Also I need to figure out how to do the disassembly,
> since I am not yet clear on how to best reach every part.

OK. Once I figured out how the side-plate slided off I was able to 
unscrew the rubidium physical package from the Aluminium frame.

It opens up somewhat like a russian doll and it is clear that it is a 
combination of magnetic shielding and thermal isolation in layers. In 
fact, it seems not to draw a lot of current. Once I got sufficiently far 
in I was able to pull out the rubidium lamp assembly. It's a huge thing, 
by far the largest rubidium set up I've seen so far with the Rubidium 
lamp being a double cavity thing creating a 1 cm long and maybe 4 mm 
wide rubidium discharge then being reflected by a copper reflector to 
form a 35 mm wide optical path through the other two glass assemblies.

The lamp lits up and it is not that bad, but I need to think. There are 
many possible causes for a bad 2nd harmonic response, and rubidium lamp 
may be just one possible problem.

Time for bed.

Oh, I *did* try to get the camera. I discovered it badly needed the 
battery to recharge, so it is charging it now.

Cheers,
Magnus