Bruce Griffiths wrote:
Garry Thorp wrote:
With the 723, you can make the reference noise as low as you want, by
heavy RC filtering. This applies whether you use its own reference or a
better external reference.
The 723 also seems to work quite happily with a feedback capacitor from
the output
Magnus Danielson wrote:
Bruce Griffiths wrote:
Garry Thorp wrote:
With the 723, you can make the reference noise as low as you want, by
heavy RC filtering. This applies whether you use its own reference or a
better external reference.
The 723 also seems to work quite happily with a feedback
Hi, Garry --
I knew from other people's measurements that 74AC was capable of better
than -160dBc/Hz when used to make a phase detector at 10MHz, but I
wanted to do a quick feasibility check on a divider for an application a
couple of years ago.
The 74AC163 was powered from a linear bench
Hi
That plot is very similar to what I have seen on AC gates.
The usual mumble words apply - that was 15 years ago and semiconductor
processes have changed a bit since then.
Bob
On Feb 26, 2010, at 5:54 AM, John Miles wrote:
Hi, Garry --
I knew from other people's measurements that 74AC
I've been following the discussion of the noise introduced by 74AC gates with
some interest.
In an attempt to achieve a clean transition, I've been using gates from
http://potatosemi.com/
Lacking the test equip. to verify the results, I've been taking the claimed
specs at face value.
I must
I have 8561a otion 3 - 4
I do not have beam current and 2nd arm .
ion pump current very low .
the tube is cold , it should be warm or not ? CS oven value is correct .
someone already had experience ?
the 5mhz is correct very close to exatlly frequenzy.
all help are welcome
i5uxj
Bruce wrote:
A little more detail is required such as:
1) What was the divided down output of the 74AC163 compared with?
The E5052B contains 2 uncorrelated test systems, and uses its 2 internal
synthesisers (with separate 10MHz ref OCXOs) as references. The signal
under test is split at the
Hello John,
Your results look very interesting. The big variation with input level
shows how important it is to get that right. Incidentally, I didn't
blame the CMOS for the 1/f^3 slope, as that was 18dB below the OCXO's
phase noise. The divider output dominated from ~100Hz outwards, and
showed
sorry for mistake , is 5061A
I have 5061a otion 3 - 4
I do not have beam current and 2nd arm .
ion pump current very low .
the tube is cold , it should be warm or not ? CS oven value is correct .
someone already had experience ?
the 5mhz is correct very close to exatlly frequenzy.
all help
Hi all,
A friend just received a thunderbolt from an ebay seller today and
asked me to check it and wire a quick power supply for him.
I used a switching power supply, pc-like, just for testing and tried
both lady heather and tboltmon. I wired the power lines as the TVB web
page, but connected
Bruce Griffiths wrote:
Only if the noise figure of the following amplifier is 4dB or so.
With no extra amplification is used one only needs a signal level of
+1dBm to achieve a phase noise floor of -178dBc/Hz if the output is
extracted through the crystal in such a way that the thermal
The tube is very well insulated and you barely feel that its warmer if at
all.
At least thats my experience with the one I have.
Best way is to measure the filament current but thats a messy job.
Suspect others will have better advice
On Fri, Feb 26, 2010 at 12:08 PM, Dott. Alfredo Rosati
Hello Francesco,
After connecting to a known good power supply, active antenna, and computer,
give it a chance to warm up and stabilize.
After warm up, I get:
+5VDC @ 0.250 A
+12VDC @ 0.12 A
-9VDC @ very low current, just barely moving the meter...
consider a hard (factory) reset.
set the
I foud missing , power at beam tube ionizer .
was a diode open , now ion pump current is high .
last calibration was made 20 tears ago , maybe this one was not
operating for long time , due to a fault .
Now I will try to apply 3500 volt as the manual .
And I hope current go low .
I someone
That is great news
Give it plenty of time to lower the current.
If you see it coming down it could easily take two or more weeks
If it does not you will need to do the procedure with a separate 3500 volt
power supply
good luck
You are ahead of me my tube had very very low beam current. Unusable.
Hi all,
in the time-nuts archive I found this very helpful post about Motorola's
old UT+ Timing receivers:
http://www.febo.com/pipermail/time-nuts/2006-April/020639.html
The attachment of the message states that there was a Date extension
modification to allow use beyond 20 years between
One way to determine the Ion Pump current is to measure the voltage on pin 3
of the +3500 VDC supply. This measures the voltage across the 10K resistor
that is in the return line of the +3500 VDC supply and is directly related
to the current flowing in the resistor.
I am in the process of
Richard (Rick) Karlquist wrote:
Bruce Griffiths wrote:
Only if the noise figure of the following amplifier is 4dB or so.
With no extra amplification is used one only needs a signal level of
+1dBm to achieve a phase noise floor of -178dBc/Hz if the output is
extracted through the crystal in
Hi Stan,
On 2/26/10, Stan, W1LE stanw...@verizon.net wrote:
Hello Francesco,
After connecting to a known good power supply, active antenna, and
computer,
give it a chance to warm up and stabilize.
After warm up, I get:
+5VDC @ 0.250 A
+12VDC @ 0.12 A
-9VDC @ very low current, just
The -12 can be anything from -7 to -12V and it will work. The units that
were removed from Grayson or Andrew equipment had a zener diode changed on
the Thunderbolt (by Trimble) that kept the power alarm from being invoked at
low values of this voltage.
73,
geo - n4ua
On Fri, Feb 26, 2010 at
Hi
Has anybody actually measured the supply sensitivity on the -12 volt line to
see weather a 5 volt change makes any noticeable difference in the output
frequency? The power on -12 is very low, so there should be negligible thermal
impact from a change.
Bob
On Feb 26, 2010, at 4:52 PM,
now ion pump current is low
-2380 present
2nd good signal
Beam 1 low only 10
The pll work if I change coarse the control line corrects the frequency
, no alarm .
But comparing the frequency to my rubidium and my z3805 there are to
much difference.
frequecymeter read9.999.999.800.25
any
Yes, I Did that, The +5 and -12 has NO effect on freq or operation of the
unit except for really far out voltages.
I tested mine with the -12 from -2 to -15 and could see no effect in the
e-11 range.
The -12 is used for the RS232 and the -Dac out so If you don't need the neg
Dac out
Hi
Depending on the supply setup, a common mode choke might also be a good idea.
The +12 runs the OCXO, so it's going to have an impact.
What about the +5 Volts? Obviously it needs to be crud free. Gross changes will
impact the temperature of the unit. What about small changes? Is it running
I am a little confused.
The 5061A only puts out 5 MHz, 1 MHz, and 100 kHz so I am not sure what you
are reading at 9.999.
After the tube pumps down and the Ion Pump I is low, switching from CS Off
to Loop Open allows the CS Oven to turn on. As the CS Oven heats up, the CS
Oven indication
Lots of questions
Same Simple answer.
Make the +12 volts is as good as you can get it, For the rest any general
purpose PS works fine.
And a Common mode choke filter does not get ride of line noise on the +12 V
or Line voltage sensitivities, both are important on the +12V
ws
Common mode choke filter does not get ride of LINE NOISE on the +12 V or
LINE VOLTAGE sensitivities...,
Please explain how a common mode choke on the +12 and ground does nothing
to help keep the supply clean.
What size is your common mode choke filter?
To have any effect on 60 Hz PS ripple
Hi
It's pretty easy to get a common mode choke that will indeed break up 120 Hz
ground loops. Often they are very low impedance. With most supplies the
rectified line is what's coming through.
Bob
On Feb 26, 2010, at 10:10 PM, WarrenS wrote:
Common mode choke filter does not get ride
I don't know of any reasonable inductor thing that is useful to reduce High
current ripple PS ripple.
There where inductors, of the small bread box size, used in very early tube
radios, But that was mostly just for low current B+ voltages.
Do you have a standard part in mind that will reduce
I think the best policy re: initial setup of the 5061A is to follow the
manual. There are clear instructions on how to set the beam current and
second harmonic indications and tune the OCXO to find the central peak. If
it is locked but not exactly at 5 MHz, either your C-field is grossly off,
or
I fully agree to John's instructions. TvB should have the manual on his web
site. If peeking is correct, check for phase alignement as well. Did you
replace the capacitor C49 about 10 uF on Synthesizer board? If it did not
fail, it will soon and start eating traces of PC board. If you need further
I see that there is a 5061 on epray with the usual evasive statement to the
effect that the seller is completely ignorant except it turns on. Is the Cs
tube liable to be OK? If so, I feel competent to fix anything else that does
not call for esoteric or exceedingly rare parts :-)
I just don't
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