[time-nuts] HP 5071A Electron Multiplier of Cesium Beam Tube

[John Miles]

It's an HP 3048A.  I have long held vague ambitions toward replacing it with
a homebrew digital system but it hasn't happened yet.

-- john, KE5FX

> -----Original Message-----
> From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com]On
> Behalf Of Mike Monett
> Sent: Monday, September 07, 2009 12:00 AM
> To: time-nuts at febo.com
> Subject: Re: [time-nuts] HP 5071A Electron Multiplier of Cesium Beam
> Tube
>
>
>   [...]
>
>   > Peak beam current with this tube is about 25 nA (-980mv pk into 40
>   > Mohms), compared  to the 80-200 nA typical range  that  the manual
>   > calls for, and the Cs resonance valley isn't much higher  than the
>   > noise floor observed with no RF applied (-550 mv versus -520 mv).
>
>   > But the  output phase noise, at least, is well  within  specs (-88
>   > dBc/Hz at  1 Hz in short time constant mode, spec=-82  dBc/Hz, and
>   > 105 in LTC mode, which is actually better than the -96 dBc/Hz spec
>   > for the option-004 tube.)
>
>   [...]
>
>   > john, KE5FX
>
>   John, out  of  curiosity, are you using  homebrew  or  commercial to
>   measure the phase noise ?
>
>   If it's homebrew, is there any other information available?
>
>   Thanks,
>
>   Mike
>
>