[time-nuts] Re: Attempting to start HP5061A {External}

Fri Feb 10 21:57:12 UTC 2023

If you have a gpsdo thats a great way to make sure the CS is on the right
peak.
Open the loop.
Adjust the CS osc to match the gpsdo.
Then close the loop.
I have never been very successful with the Zeeman method.
With respect to the CS off and jump. When the CS is turned off there is a
fair power hit as it all shuts down.
Now whats a bit funny is that some people on time nuts adjust the
oscillator with CS on to have a zero offset/correction voltage.
Then they turn the CS oven off.
This saves power and the CS's. The Cs's do run out.
Curious if the CS tube is an option 004. HP ran the 004s at a higher temp
and that burned off more Cs for a better signal to noise ratio at a cost of
tube life.
Regards
Paul

On Fri, Feb 10, 2023 at 4:33 PM Matt Krick <dcflux at gmail.com> wrote:

> Yes, it stayed green,
>
> It didn't seem to loose time last night, but I did notice the clock will
> gain a second or two when you switch between CS OFF and Loop Open
>
> I'm going to do another tune up now that it's a bit more stable and I have
> a signal generator to do the Zeeman alignment.
>
> On Fri, Feb 10, 2023 at 6:07 AM paul swed <paulswedb at gmail.com> wrote:
>
>> Matt that would indeed be odd that the clocks off by that huge amount.
>> If you manually adjusted the 5061 by the manual, its possibly set it to
>> the wrong peak. There are 3 peaks. The center is the highest.
>> But even if you were on one of the side peaks its not a 40 minutes offset.
>> So maybe a glitch. Especially if everythings been off a long time.
>> Lock light still green?
>> Regards
>> Paul
>>
>> On Thu, Feb 9, 2023 at 11:34 PM Matt Krick <dcflux at gmail.com> wrote:
>>
>>> The Beam I current rose up to 45 and the front panel clock was 40
>>> minutes slow since last night but I'm going to reset it and keep an eye on
>>> it, might of just been a glitch in the Matrix.
>>>
>>> On Thu, Feb 9, 2023 at 1:00 PM paul swed <paulswedb at gmail.com> wrote:
>>>
>>>> Great to hear and with a reading I see in the pix you included thats a
>>>> nice tube.
>>>> Appears to be 38?? Granted the beam current isn't absolute.
>>>> I have a unit with 0 beam current and it still locks and is consistent
>>>> with the other CS units.
>>>> Regards
>>>> Paul
>>>> WB8TSL
>>>>
>>>> On Thu, Feb 9, 2023 at 1:42 AM Matt Krick via time-nuts <
>>>> time-nuts at lists.febo.com> wrote:
>>>>
>>>>> I am pleased to report that the unit is Alive and Ticking!
>>>>>
>>>>> After 30 minutes of the cycling my unit stabilized. I have it another 2
>>>>> hours of CS OFF mode and then started it again this time stable with no
>>>>> cycling.
>>>>>
>>>>> With Loop Open the Beam meter started at 2 and slowly climbed to about
>>>>> 15
>>>>> after about 20 minutes where I did a rough tune.
>>>>>
>>>>> After another 20 minutes I went with Oper mode and centered the coarse
>>>>> tuning getting a peak meter reading of 34. Pegging control to -50
>>>>>
>>>>> I then centered the control reading by again tuning coarse and hit the
>>>>> reset button and got the continuous operation to light.
>>>>>
>>>>> I set the clock to my watch and will compare tomorrow
>>>>>
>>>>> On Wed, Feb 8, 2023, 15:22 Aiden Gibson via time-nuts <
>>>>> time-nuts at lists.febo.com> wrote:
>>>>>
>>>>> > Hi Matt,
>>>>> >
>>>>> > Just to add another 2c to this thread, I went through roughly the
>>>>> same
>>>>> > process Jim describes with my 5061A.
>>>>> >
>>>>> > I also kept the hot wire ionizer powered on in order to catch any
>>>>> neutral
>>>>> > particles which may have been affecting the vacuum.
>>>>> >
>>>>> > I took some measurements of the process to get a rough "pump curve"
>>>>> which
>>>>> > can be seen here:
>>>>> >
>>>>> >
>>>>> >
>>>>> https://docs.google.com/spreadsheets/d/1zsTUAiDZ92Eb-2lID9Hkoe7ByOylcx_LJ3ktGqG_uac/edit?usp=drivesdk
>>>>> >
>>>>> > Best of luck!
>>>>> > -Aiden
>>>>> >
>>>>> > Sent from my Verizon, Samsung Galaxy smartphone
>>>>> >
>>>>> >
>>>>> >
>>>>> > -------- Original message --------
>>>>> > From: Jim Muehlberg via time-nuts <time-nuts at lists.febo.com>
>>>>> > Date: 2/8/23 17:34 (GMT-05:00)
>>>>> > To: Matt Krick via time-nuts <time-nuts at lists.febo.com>
>>>>> > Cc: Jim Muehlberg <jmuehlbe at nrao.edu>
>>>>> > Subject: [time-nuts] Re: Attempting to start HP5061A {External}
>>>>> >
>>>>> > Hi Matt,
>>>>> >
>>>>> > I just went through this when resurrecting a 5061A option 4 that was
>>>>> > about to be scrapped (Horrors!).  My ion pump power supply was
>>>>> flakey,
>>>>> > but after I fiddled with it, I got it to work.  I then saw the same
>>>>> > behaviour.  Ultimately, I connected an external supply to the ion
>>>>> pump
>>>>> > and left it powered for a few days.  This cleaned (or whatever
>>>>> happens)
>>>>> > the tube and I was able to lock it.  FWIW, the supply I connected was
>>>>> > about 7 kV.  The label said 3KV, but apparently that was under the
>>>>> rated
>>>>> > load.  In any event, I thought I wrecked the whole thing.  I was
>>>>> assured
>>>>> > by some time nuts that it was OK, and it was.  It's been running
>>>>> > continuously now for about 2 months.  Here's an ADEV plot for fun...
>>>>> >
>>>>> >    Measured against another opt 4.  Both units have an unknown
>>>>> history,
>>>>> > and they are 40 year old tubes, so I consider this a success!  Good
>>>>> > enough anyway.
>>>>> >
>>>>> > Good luck, and keep one hand in your pocket.
>>>>> >
>>>>> > Jim
>>>>> >
>>>>> > On 2023-02-08 12:39 AM, Matt Krick via time-nuts wrote:
>>>>> > > Hello,
>>>>> > >
>>>>> > > I recently acquired a HP5061A and I am attempting to start it but
>>>>> there
>>>>> > are
>>>>> > > some things that are puzzling me.
>>>>> > >
>>>>> > > Per the manual I have left the unit plugged in for 24 hours with
>>>>> mode set
>>>>> > > to CS OFF set to and I have observed the Ion Pump readings go to 0
>>>>> after
>>>>> > > about 3 or 4 minutes of first plugging it in.
>>>>> > >
>>>>> > > So now I am attempting to power up the tube by switching to Loop
>>>>> open
>>>>> > and I
>>>>> > > can hear another power supply engage. My Ion Pump reading climbs
>>>>> to about
>>>>> > > 30 after about 10 seconds and then the power supply shuts off.
>>>>> Then I get
>>>>> > > into a cycle of about 2 seconds on for 10 seconds off with the Ion
>>>>> Pump
>>>>> > > going between 20-30 or thereabouts.
>>>>> > >
>>>>> > > I'm not sure if this is normal and part of the pumping down
>>>>> process.
>>>>> > > Should I leave it on or keep trying to run it on CS OFF?
>>>>> > >
>>>>> > > Am I correct in assuming that with CS OFF the +3500V supply is
>>>>> running
>>>>> > and
>>>>> > > that is what is acting as the Ion Pump to evacuate the tube, and
>>>>> then
>>>>> > when
>>>>> > > I switch to Loop open that also powers  up the Cesium Heater and
>>>>> the
>>>>> > -2500V
>>>>> > > supply?
>>>>> > >
>>>>> > > I have experience with high power Triodes and Tetrodes where you
>>>>> run the
>>>>> > > filaments without high voltage to help evacuate the tube so I'm
>>>>> unsure
>>>>> > how
>>>>> > > a tube like this operates.
>>>>> > >
>>>>> > > Thank you!
>>>>> > > _______________________________________________
>>>>> > > time-nuts mailing list --time-nuts at lists.febo.com
>>>>> > > To unsubscribe send an email totime-nuts-leave at lists.febo.com
>>>>> > --
>>>>> >
>>>>> > Jim Muehlberg
>>>>> > Senior Engineer
>>>>> >
>>>>> > National Radio Astronomy Observatory
>>>>> > ngVLA Local Oscillator Lead
>>>>> >
>>>>> > 1180 Boxwood Estates Rd B-111
>>>>> > Charlottesville, VA 22903-4602
>>>>> > P 434.296.0270
>>>>> > C 434.422.2017
>>>>> > _______________________________________________
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>>>>> > _______________________________________________
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>>>>> >
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>>>>
>>>>