[time-nuts] "The Penultimate HP5065 A15"

[Magnus Danielson]

Hi Poul-Henning,

On 2020-08-04 12:35, Poul-Henning Kamp wrote:
> --------
> Magnus Danielson writes:
>
>> If that is the range you aim to improve, then I strongly recommend you
>> do re-read the postings I did about phase noise in detector range, as I
>> have showed that phase-noise get's mixed down to DC and increase the
>> noise there. With very ugly and hand-wavey hack I was able to
>> significantly reduce that noise essentially by cleaning up the
>> phase-noise.
> Ohh, absolutely.
>
> My plan is to put a modulated DDS synth in to get a much more modern
> detector system.

That would help naturally, given that OCXO phase-noise is well taken
care off.

I'm considering swapping out the 00105 oscillators, way too much noise
to be useful.

> But right now the zener on my a15 is better at measuring temperature
> than holding voltage stable, so I'm addressing that first.
>
> See the 3rd graph here:
>
> 	http://phk.freebsd.dk/hacks/HP5065A/20150908_a15/
>
Temperature measurements is nice. :) Yeah, I've seen that too.
>>>> I would go for the LTZ1000 if you can. The LM399 has gone out of
>>>> fashion for a reason: [...]
>>> Yes, I know, being also a volt-nut :-)
>> I have not yet jumped down that rabbit-hole as I am by far not done with
>> the current one. :)
>>
>> I've been looking at the LTZ1000 and one day I may get some.
> You *really* want the version of it which is packaged in the attractive
> and *incredibly* useful "HP3458A" cabinet :-)
>
How nice of HP ehm Agilent to supply it in a pre-packaged format with
some auxillary functionality to go with it. :)

Yeah, I got a pair of "HP3457A" cabinets here, but so far no "HP3458A"
cabinet. Hopefully soon enough.

Cheers,
Magnus