On 2017-01-04 11:08, Attila Kinali wrote:
Hoi Attila
So it's the usual curiosity and the need to have a reference for
your 23cm radios?
Yes exactly.
Advantage of an GPSDO over an Rb is that you know it's on frequency,
while with an Rb it can be off without you knowing it, if the
electronics or the physics package is defect.
This is in line with what I've read. Maybe the decision to go for the
Rb was not the best one but I don't think that it's that bad either.
I was offered the opportunity to calibrate my modified Rb standard
against a fellow ham's two 10 MHz standards and his GPSDO.
BTW: there is a whole new way of looking at statistics of time series
in the field of time and frequency control, which you might find
interesting.
The NIST Technote 1337[1] and NIST special publication 1065[2] give a
nice
overview of the methods applied.
This is very interesting thank you for sharing those!
Unfortunately, it's not that easy :-)
I don't know the exact construction of the FE-5650, but usually the
physics
package is just a normal aluminium microwave cavity, without
shielding.
The mu-metal shield is usually the housing of the whole device
itself.
Hm I thought I had done my homework on this one but I never have
issues with being proven wrong. For what it's worth, here are two
pictures
of the unit in question:
http://2.bp.blogspot.com/_8uoOi3ZInLQ/SdZfVfpcBaI/AAAAAAAABB8/YvZ2-l0GhMI/s400/DSCN4592.JPG
http://www.dty.sakura.ne.jp/keisoku/rubidium/FE5650-2.jpg
The shiny face plate is where I would be drilling. For what it's worth,
it is very light, nonmagnetic, does not look like the mu-metal I've
seen in disassembled hard disks and very much looks like machined
aluminum... Would a compromised mu-metal shield show during calibration
if the standard was physically rotated?
Best regards and thank you
Matt
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