Hi
Try rotating the 5065 180 degrees and see if the frequency shifts. If it shifts
more than a little, you have something local that is magnetized.
Bob
> On Dec 3, 2020, at 1:23 PM, paul swed wrote:
>
> Well Bob what an unusual comment about large magnetic fields. It just so
> happens that
paul swed writes:
Change the polarity of the C-field by swapping the two wires ?
If that changes your frequency, you know you have a residual magnetic
field pushing the frequency of your atoms.
But be aware that the frequency shift does not tell you the magnitude
of the residual field,
Paul: You can have some fun with this:
A vertical line current flow in the neighborhood of 30,000 amperes,
pulse risetime on the order of 2-5 microsec, fall time about 40. Kind of
a giant magnetic play toy.
Don Latham
On 2020-12-03 11:23, paul swed wrote:
Well Bob what an unusual comment
The 5065 is 2.3 E-11. Thats far more normal.
Regards
Paul.
On Thu, Dec 3, 2020 at 1:27 PM paul swed wrote:
> Please ignore the drift rate numbers I shared they are wrong.
> Will get a new set of numbers that I expect will be normal.
>
> On Thu, Dec 3, 2020 at 1:23 PM paul swed wrote:
>
>> Well
Please ignore the drift rate numbers I shared they are wrong.
Will get a new set of numbers that I expect will be normal.
On Thu, Dec 3, 2020 at 1:23 PM paul swed wrote:
> Well Bob what an unusual comment about large magnetic fields. It just so
> happens that maybe I actually had one about 8
Well Bob what an unusual comment about large magnetic fields. It just so
happens that maybe I actually had one about 8 weeks ago. Its called a
lightning strike about 60' away. Just found the actual 100' pine tree 2
days ago. I had been looking but it sounded like it hit in the opposite
direction.
Just rechecked everything as the system seems far to good to be true. Yet
everything is actually correct. It is drifting fast compared to the TBolt.
But its very small. I am still in the 1.5-1.7ns range after 2 hours and 43
minutes. I believe by calculation that 1.5 E-13. That makes no sense.
Hi
I don’t believe that the quantum transitions are sensitive enough to minor
temperature
shifts to account for a 1 or 2 ppb sort of shift….. Magnetic field, ( giant
magnetic play toy
moved next to Rb … ) yes that will do the trick, but temperature … tough to do
…
Everything I can find
Hi Poul
At least the front panel meter readings do not show any changes. Perhaps an
increase of 1 count sub tick mark changes that I would attribute to typical
drift. Looking over years the readings are consistent. Will say the second
harmonic level is high at 55. But its been that high in the
Could it be the thermostat circuits have shifted so you run at a
different temperature now ?
--
Poul-Henning Kamp | UNIX since Zilog Zeus 3.20
p...@freebsd.org | TCP/IP since RFC 956
FreeBSD committer | BSD since 4.3-tahoe
Never attribute to malice what can
Well the 5065 has been cooking overnight.
Started a test this morning a scope Tbolt channel A and 5065 chnl B
5ns/div. Its +1.5 ns after 1 hour and 22 minutes. Much as I have been used
to in the past. Have to get excel out to see what that all means.
That in know way explains why it essentially
For everyone when the cfield pot is at 0.0 its 2.5ma and at 9.9 its 6.38ma.
The jump is over 4 major divisions of the cfield pot and I still did not
match the reference..
So looking at the synth chart on page 3-9 started to see how far it had
gone.
Tube says the switch should be 8714 or -240 E-10
Hi
Ok, if that still turns out to be correct … that’s just about 2 ppb. (
1.6667…).
To do that with the C field, you would need to make a *major* change. It’s
essentially the whole range of the pot. You already know that it’s off in the
direction of needing more counts on the dial. I *think*
Yes absolutely it can go back and it is the same offset. I can get real
numbers from memory 3 seconds for 5ns drift and the units slow. Will
confirm and reshare.
Regards
Paul.
On Wed, Dec 2, 2020 at 2:52 PM Bob kb8tq wrote:
> Hi
>
> Just double checking….. Are we still after a change went past
Hi
Just double checking….. Are we still after a change went past 1/3 of the pot
range?
Can we get the pot back to the original location and measure the frequency
offset
(even if only in a crude fashion)?
Best guess is still that this should be a ppb or more of shift. If it’s down in
the
Corby will check. Though in looking at the cfield circuits it does appear
all to be correct. Its some other odd offset that has crept in.
Thanks
On Wed, Dec 2, 2020 at 1:56 PM wrote:
> Paul,
>
> One other thing to check.
>
> Put a DC coupled scope on the C-field pot wiper and rotate the pot
Paul,
One other thing to check.
Put a DC coupled scope on the C-field pot wiper and rotate the pot back
and forth.
Make sure there are no jumps or noise.
Sometimes the pot gets noisy in a section.
Rotating it back and forth across the bad sections will usually clean it
up.
Cheers,
Corby
Hi
Ok, if the synth is off the “suspect” list …. *and* it’s a good solid lock.
Back to the C field.
If it jumped 4x10^-11, that’s a very different thing than jumping 2x10^-9.
Finding
the “source” of a 0.04 ppb shift is going to be a lot harder than finding a 2
ppb
gotcha. Best to nail down
Hello to the group.
Last night I dug further into the 5065 along with a lot of reading.
The synth is producing the correct frequency according to the charts here
and in the manual.
I also now see that any logic I may have assumed about the
thumbwheel switches is completely wrong.
The test tonight
> To make any sense at all out of the synthesizer settings, you need the magic
> table in
> the manual. They are very random and not all settings actually work ( =
> produce a
> stable output).
A few of the entries have very much longer moduli than the rest,
and those will probably be less
Hi
To make any sense at all out of the synthesizer settings, you need the magic
table in
the manual. They are very random and not all settings actually work ( = produce
a
stable output).
Bob
> On Dec 1, 2020, at 3:20 PM, paul swed wrote:
>
> A quick update. Several people have made very
paul swed writes:
>Bob mentioned flipping the synthesizer switch. Heck they have been sitting
>at 8714 (Also on the tube label) for 30 years. I did and it did not fix
>the problem. But I went through the switch seeing how each section behaved.
>By dropping to 8614 [...]
Please notice
paul swed writes:
> > Also you can kludge in an HP 3325A/B in place of the A1 synthesizer to
> > see if that's the problem.
3336 or even 33120 works fine too.
--
Poul-Henning Kamp | UNIX since Zilog Zeus 3.20
p...@freebsd.org | TCP/IP since RFC 956
FreeBSD committer
A quick update. Several people have made very good comments. Some online
and offline.
Bob mentioned flipping the synthesizer switch. Heck they have been sitting
at 8714 (Also on the tube label) for 30 years. I did and it did not fix
the problem. But I went through the switch seeing how each
Hi
…… the synth output comes right out of the BNC on the front panel. Pretty
easy to hook a counter to. Also a good place to feed in an external synth.
Bob
> On Dec 1, 2020, at 2:11 PM, paul swed wrote:
>
> Corby I like the 3325 suggestion. I have a 3335 that I can lock together
> with
Corby I like the 3325 suggestion. I have a 3335 that I can lock together
with everything.
That will help identify a synth issue.
Thanks
Paul.
On Tue, Dec 1, 2020 at 12:24 PM wrote:
> Paul,
>
> C-field current is adjustable from 2.5 to 6ma.
>
> I use a clip on milliammeter.
>
> Also you can
Paul,
C-field current is adjustable from 2.5 to 6ma.
I use a clip on milliammeter.
Also you can kludge in an HP 3325A/B in place of the A1 synthesizer to
see if that's the problem.
Cheers,
Corby
___
time-nuts mailing list --
Hi
Well that puts it at 5/3 = 1.3 ppb low. The C field *should*adjust over a
2 ppb-ish range. Assuming you were near center, that puts the shift in the
“couple of ppb” range. Very much the sort of thing the synth could do.
Bob
> On Dec 1, 2020, at 9:44 AM, paul swed wrote:
>
> Bob
> I did
Bob
I did not see your response before responding to Poul.
This morning I did flip those switches and agree that I may have something
going on in the synthesizer. The offset that showed up is a drift of 5ns in
3 seconds and its running slow.
I do have the offsets from past measurements. Will have
Hi
The C field coil resistance is low enough that you have something in the
vicinity
of 10mv across it. If you want to check the C field regulator, I’d just pop a
wire and
put a meter in series with the coil.
My bet: your synthesizer has slipped a bit somewhere. I’d check it’s output
against
paul swed writes:
> Guessing far less than 3 ma. by adding up resistors.
More like typical 4 mA: there is a factory select resistor in
parallel with the current-setting resistor.
--
Poul-Henning Kamp | UNIX since Zilog Zeus 3.20
p...@freebsd.org | TCP/IP since RFC 956
Hello to the group.
Was time for the quarterly Cesium and RB checks in an effort to support our
local power company.
I discovered that there is an issue with the HP5065a Rubidium reference.
The frequency has slowed and the cfield pot can not make up for the jump.
Normally a few small tick marks
32 matches
Mail list logo
