[time-nuts] FE-5650A option 58 tuning word for 10 MHz output
Mathias Weyland
mathias at weyland.ch
Sun Jan 8 14:33:43 UTC 2017
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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