Re: [time-nuts] 53132A triggering

[Hal Murray]

> For a low duty cycle pulse, the ac coupled signal will be approximately the
> same as if it were dc coupled. Not sure I follow what you mean. There will
> be only one rising edge for a narrow pulse ac coupled, as the falling edge
> occurs much quicker than the HPF time constant. 

If there is overshoot, it will be undershoot on the falling edge.  You can 
trigger on the undershoot if you are triggering on rising edge and the 
trigger level is slightly below ground.


-- 
These are my opinions.  I hate spam.



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Re: [time-nuts] 53132A triggering

[Charles Steinmetz]

Bob wrote:


Most PPS signals these days are very low duty cycle. If you AC couple them, you 
can easily be triggering on the wrong edge.


???  All of the triggers I'm familiar with have slope selection (rising 
edge/falling edge), and in my experience HP counters do not have 
problems mistaking a falling edge for a rising edge.  I suppose there's 
always a first time, but


See the attached image, which shows both the DC (green) and AC (red) 
trigger channels.  The value I used for C1 came from the 5370B input 
amplifier.  I shortened the pulse to 10uS just because 10 more uS of 0v 
baseline didn't really add anything useful.  I've shown two trigger 
levels, 1.25v (half peak) and 0.5v.  I would generally use 0.5 to 0.75v 
with a 2.5v logic pulse, unless experience showed that a different value 
worked better in the particular instance.


In both the DC and AC cases, the next rising edge that transits the 
trigger points is the rising edge of the following PPS pulse.


Best regards,

Charles


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Re: [time-nuts] 53132A triggering

[Scott Stobbe]

For a low duty cycle pulse, the ac coupled signal will be approximately the
same as if it were dc coupled. Not sure I follow what you mean. There will
be only one rising edge for a narrow pulse ac coupled, as the falling edge
occurs much quicker than the HPF time constant.

On Friday, 16 September 2016, Bob kb8tq  wrote:

> Hi
>
> Most PPS signals these days are very low duty cycle. If you AC couple
> them, you can easily be triggering on the wrong edge. With the narrow pulse
> it may not be very obvious.
>
> Bob
>
> > On Sep 16, 2016, at 5:46 PM, Charles Steinmetz  > wrote:
> >
> > Bob wrote:
> >
> >> Set it to:
> >>
> >> 1) DC coupled (AC does not go low enough)
> >> 2) 50 ohms if your driving source will tolerate it, otherwise 1 meg ohm.
> >> 3) Manual trigger mode (Auto is to fast and it forgets where the
> trigger should be)
> >> 4) Trigger level around 1/2 the PPS P-P voltage
> >
> > I would just add the following:
> >
> > 1)  I'd be very surprised if AC coupling wouldn't work fine with a
> typical PPS pulse, which has very fast edges (low nS).  No LF response is
> required.  Indeed, AC coupling will keep any LF noise out (not that we
> expect much in this application).  This is true even if the PPS is a 50%
> duty-cycle square wave -- the spikes that get through every 500mS,
> alternating positive and negative, will have fast, accurate leading edges
> and will be way longer than necessary for proper triggering.
> >
> > 2)  If your source will not tolerate a 50 ohm load, buffer it.  Any
> significant length of cable between the source and a 1M termination will
> just slaughter your pulse.
> >
> > 4)  The relevant peak voltage is the actual voltage at the counter input
> connector -- which may be only 1/2, or possibly even less, of the nominal
> logic level, depending on the source impedance.
> >
> > Best regards,
> >
> > Charles
> >
> >
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Re: [time-nuts] 53132A triggering

[Tom Miller]

- Original Message - 
From: "Charles Steinmetz" 

To: 
Sent: Friday, September 16, 2016 5:46 PM
Subject: Re: [time-nuts] 53132A triggering



Bob wrote:


Set it to:

1) DC coupled (AC does not go low enough)
2) 50 ohms if your driving source will tolerate it, otherwise 1 meg ohm.
3) Manual trigger mode (Auto is to fast and it forgets where the trigger 
should be)

4) Trigger level around 1/2 the PPS P-P voltage


I would just add the following:

1)  I'd be very surprised if AC coupling wouldn't work fine with a typical 
PPS pulse, which has very fast edges (low nS).  No LF response is 
required.  Indeed, AC coupling will keep any LF noise out (not that we 
expect much in this application).  This is true even if the PPS is a 50% 
duty-cycle square wave -- the spikes that get through every 500mS, 
alternating positive and negative, will have fast, accurate leading edges 
and will be way longer than necessary for proper triggering.


2)  If your source will not tolerate a 50 ohm load, buffer it.  Any 
significant length of cable between the source and a 1M termination will 
just slaughter your pulse.


4)  The relevant peak voltage is the actual voltage at the counter input 
connector -- which may be only 1/2, or possibly even less, of the nominal 
logic level, depending on the source impedance.


Best regards,

Charles


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Don't forget to select positive edge.


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Re: [time-nuts] Why are PPS pulses so narrow? (was: 53132A triggering)

[Bob kb8tq]

Hi

It is sort of an " everybody does it " sort of thing. Various justifications:

Less power is used / less heat in the drivers and terminations.

Transformer coupling works better ( lower delay ) with narrow pulses

 Anything over 1 us has been "really long" in terms of logic speeds 
since the 1960's

 A definite duty cycle "bias" let's you detect an inverted pulse.

The only real reason is "that's the way it's done". Big Customers ask for it 
that way. Suppliers deliver what is asked for. Nobody complains, nothing 
changes.

Bob

> On Sep 16, 2016, at 7:44 PM, Peter Vince  wrote:
> 
> Can I ask why PPS pulses are so narrow?  It makes them difficult to see on
> a 'scope, and difficult to detect on a PC.  And, as Bob said, far less
> obvious if you trigger off the wrong edge.
> 
> Peter
> 
> 
> 
>> On 16 September 2016 at 23:55, Bob kb8tq  wrote:
>> 
>> Hi
>> 
>> Most PPS signals these days are very low duty cycle. If you AC couple
> them, you can easily be triggering on the wrong edge. With the narrow pulse
> it may not be very obvious.
>> 
>> Bob
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[time-nuts] Why are PPS pulses so narrow? (was: 53132A triggering)

[Mark Sims]

I asked this very question a few years back... the consensus was to lower power 
dissipation into the typical 50 ohm load.
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Re: [time-nuts] 53132A triggering

[Charles Steinmetz]

Bob wrote:


Set it to:

1) DC coupled (AC does not go low enough)
2) 50 ohms if your driving source will tolerate it, otherwise 1 meg ohm.
3) Manual trigger mode (Auto is to fast and it forgets where the trigger should 
be)
4) Trigger level around 1/2 the PPS P-P voltage


I would just add the following:

1)  I'd be very surprised if AC coupling wouldn't work fine with a 
typical PPS pulse, which has very fast edges (low nS).  No LF response 
is required.  Indeed, AC coupling will keep any LF noise out (not that 
we expect much in this application).  This is true even if the PPS is a 
50% duty-cycle square wave -- the spikes that get through every 500mS, 
alternating positive and negative, will have fast, accurate leading 
edges and will be way longer than necessary for proper triggering.


2)  If your source will not tolerate a 50 ohm load, buffer it.  Any 
significant length of cable between the source and a 1M termination will 
just slaughter your pulse.


4)  The relevant peak voltage is the actual voltage at the counter input 
connector -- which may be only 1/2, or possibly even less, of the 
nominal logic level, depending on the source impedance.


Best regards,

Charles


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[time-nuts] Why are PPS pulses so narrow? (was: 53132A triggering)

[Peter Vince]

Can I ask why PPS pulses are so narrow?  It makes them difficult to see on
a 'scope, and difficult to detect on a PC.  And, as Bob said, far less
obvious if you trigger off the wrong edge.

 Peter



On 16 September 2016 at 23:55, Bob kb8tq  wrote:
>
> Hi
>
> Most PPS signals these days are very low duty cycle. If you AC couple
them, you can easily be triggering on the wrong edge. With the narrow pulse
it may not be very obvious.
>
> Bob
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Re: [time-nuts] A new take on the all-hardware GPSDO concept

[Mark Spencer]

Hi Lars.   I own a G3RUH (Miller) GPSDO.

>From what I can recall  While testing mine with  my collection of 
>HP5370B's and my assortment of references the performance of mine while locked 
>was generally comparable to the one in the link you provided.   I never tested 
>it "un locked."  

I couldn't measure phase noise and the performance of my test setup at taus of 
less than 100 seconds or so was probably a limitation as well.   My references 
(BVA OCXO, PRS10 rb and a cherry picked Z3805 GPSDO) probably weren't really 
good enough either.

It is a nice unit that I have currently loaned out to a local amateur radio 
operator.   Acquiring it lead to me spending a sizeable amount of time and 
money on time nuts pursuits over the years.

Sent from my iPhone

> On Sep 16, 2016, at 1:13 PM, Lars Walenius  wrote:
> 
> Hi Nick,
> 
> Jim Millers design is very clever and as I see can give results as good as a 
> digital approach but it has the same limitations:
> The GPS jitter and the oscillator jitter in combination with the loop 
> bandwidth.
> 
> The only ADEV I have seen for the Miller GPSDO is this one  
> http://www.leapsecond.com/pages/gpsdo/  .
> Can anyone point me to other tests?
> 
> The ADEV I see on leapsecond.com indicates for me a time constant of around 
> 200seconds. That is what you get with a OCXO range of 0.25ppm. You don´t need 
> to have a large RC-filter. The original R1-C1 time constant with 16 seconds 
> time constant will work as long as the internal oscillator in the Jupiter-T 
> is at least some Hz away from a multiple of 10kHz. If that is true the 
> sawtooth out of the Jupiter will have enough high frequency to be easily 
> filtered by the RC. This is of course a risk. See for example: 
> https://www.febo.com/pipermail/time-nuts/2005-August/019106.html . If you get 
> a hanging bridge you have at least as much trouble as a non sawtooth 
> corrected GPSDO and probably much worse as the RC filter is only 16s. In the 
> digital approach the prefilter may filter away the hanging bridge (in best 
> case).
> 
> As I understand the Miller GPSDO with a OCXO with a 0.25ppm range and 10kHz 
> into an XOR phase detector and 16s RC will be very similar to a digital 
> approach with a TIC (Time interval counter ) with +-25us range followed by a 
> prefilter with time constant 16s and a loop with just the P-term with a time 
> constant of 200secs. As it has no I-term it will have slightly less noise but 
> the output phase will drift as soon as the OCXO drifts (as a FLL). The 
> resolution of the XOR phase detector (TIC) will be limited by the noise but 
> as 0.1mV is 1ns the resolution can be seen as better than 1ns is my 
> conclusion. A problem might be that the output of the XOR drifts with the 5V 
> supply but this can be seen as the same problem as the DAC drift in a digital 
> approach.
> 
> My conclusion (without testing) is that the Jupiter-T 10kHz is very good but 
> not better than the sawtooth corrected outputs from M12 or LEA6T receivers. 
> That is the ADEV can be approximated by 1E-9/Tau (1E-12 at 1000s) in good 
> conditions.
> 
> My experience with the Venus838-T is only 2 weeks but disappointing. This can 
> also be guessed from the datasheet ADEV curve, that I guess is sawtooth 
> corrected values as it starts at 3E-9 at 1s, but is only 1E-11 at 1000s a 
> factor 10 worse than I get with the LEA-6T with the same antenna and setup. 
> If anyone have ADEV-MDEV curves to share I would be glad to see what can be 
> achieved with the venus838-T. My conclusion is also that sawtooth correction 
> is useless on my 838-T.
> 
> Lars
> 
> 
>> Nick wrote:
> 
>> Jim Miller's 10 kHz GPSDO that’s been referenced here has either solved this 
>> problem, or the 10 kHz output of the >Jupiter is substantially better than 
>> the Venus’ 10 MHz output, or the design doesn’t give the results time-nuts 
>> expect >from a GPSDO. Which of those applies?
> 
> 
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Re: [time-nuts] 53132A triggering

[Bob kb8tq]

Hi

Most PPS signals these days are very low duty cycle. If you AC couple them, you 
can easily be triggering on the wrong edge. With the narrow pulse it may not be 
very obvious. 

Bob

> On Sep 16, 2016, at 5:46 PM, Charles Steinmetz  wrote:
> 
> Bob wrote:
> 
>> Set it to:
>> 
>> 1) DC coupled (AC does not go low enough)
>> 2) 50 ohms if your driving source will tolerate it, otherwise 1 meg ohm.
>> 3) Manual trigger mode (Auto is to fast and it forgets where the trigger 
>> should be)
>> 4) Trigger level around 1/2 the PPS P-P voltage
> 
> I would just add the following:
> 
> 1)  I'd be very surprised if AC coupling wouldn't work fine with a typical 
> PPS pulse, which has very fast edges (low nS).  No LF response is required.  
> Indeed, AC coupling will keep any LF noise out (not that we expect much in 
> this application).  This is true even if the PPS is a 50% duty-cycle square 
> wave -- the spikes that get through every 500mS, alternating positive and 
> negative, will have fast, accurate leading edges and will be way longer than 
> necessary for proper triggering.
> 
> 2)  If your source will not tolerate a 50 ohm load, buffer it.  Any 
> significant length of cable between the source and a 1M termination will just 
> slaughter your pulse.
> 
> 4)  The relevant peak voltage is the actual voltage at the counter input 
> connector -- which may be only 1/2, or possibly even less, of the nominal 
> logic level, depending on the source impedance.
> 
> Best regards,
> 
> Charles
> 
> 
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[time-nuts] HP-105B Manual

[Jeremy Nichols]

[I keep forgetting to send these messages in plain text only. Sorry!]

Somewhere in one of these 105B discussions were some comments on the 
manual and its enormous set of change sheets. So I asked my wife, the 
former Laura Cline of HP Santa Clara marketing (post-sales support), 
"Why didn't you revise that manual?" She replied that she had offered to 
do so several times but management always refused. Apparently they kept 
thinking (hoping?) sales would drop to the point where they could 
discontinue the product, so why bother? I think when we retired in 1997 
they were still selling it!


Jeremy

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Re: [time-nuts] 53132A triggering

[David]

The new ones don't?  That would be annoying.

My old Racal-Dana 1992 remembers when in standby mode but not if it
loses power.

On Fri, 16 Sep 2016 15:21:50 -0400, you wrote:

>Thanks, Bob.  I just tried that and got solid results.  One nice thing about 
>the 5370 vs this newer stuff is that the knobs and switches stay in the same 
>place through power cycles!
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Re: [time-nuts] HP-105B Battery Replacement?

[David]

I have a pair of Liebert GTX2-700RT online UPSes and they work well; I
just replaced the batteries, lubricated the fans, and cleaned the dust
out of them a couple weeks ago.  They have that sort of standard 4
prong socket on the back for external batteries.

But unlike my two Powerware Prestige EXT UPSes, they only operate with
batteries installed.  The Prestige EXT will operate as a super power
conditioner without batteries which is just as well since it uses 5 x
12V 4AH batteries for 60 volts instead of the more standard and less
expensive 4 x 12V 7AH-9AH batteries.  These have a 4 pin Molex type of
socket on the back for battery expansion.  I have considered
converting these to use a bank of supercapacitors but I suspect the
charge circuit would have a fit charging them from zero volts.

I picked these up inexpensively from http://www.refurbups.com/ but I
have not seen any deals on refurbished online UPSes there for quite a
while now.

If your equipment can run on 12 volts DC, then there are less
expensive solutions like one of those Belkin 12 volt battery backed up
power supplies that some ISPs issue to their customers or something
home grown.

On Fri, 16 Sep 2016 04:56:35 -0400, you wrote:

>Actually the larger SmartUPS series can run for hours providing a large enough 
>battery string is available I have a SmartUPS RM3000 running data rack 
>this has 2 external battery boxes and will run everything for 6 hours.
>
>For TimeNuts applications though I'd recommend a Liebert UPS as this is a 
>'online' UPS as in input is converted to DC and used to float batteries and 
>drive a power oscillator for a true sine output and in a power interruption 
>there is no transfer time or transients on the output
>
>Content by Scott
>Typos by Siri
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Re: [time-nuts] Lady Heather's plotting functions

[Mark Sims]

Not just GPSDO's...  now works with just about any GPS receiver, timing or 
otherwise  (and with GPSD).   Code is now pushing 60,000 lines. 


From: Scott Stobbe 
Sent: Friday, September 16, 2016 6:27 PM
To: hol...@hotmail.com; petervince1...@gmail.com; Discussion of precise time 
and frequency measurement
Subject: Re: [time-nuts] Lady Heather's plotting functions

The joys of a small display, why couldn't I see that. Many thanks Mark & Peter.

Soon to be the emac's of gpsdo's (in the good, can do anything sense) well done.



On Wed, Sep 14, 2016 at 12:27 AM, Mark Sims 
> wrote:
You can set the view interval to any value with the "V" keyboard command 
(default is one second per pixel, 1 minute per horizontal division).

Above the plot area is a section that give the view interval in total time (60 
minutes in those plots) and time per division (5 minutes per division).   Lady 
Heather logs all the data in a circular buffer and when it fills, the oldest 
data is replaced by newer data).The default plot queue size is 3 days... 
the /q command line option for can change that (n.b.  and error in the help 
screen says the default is 30 days).

Lady Heather decimates the queue data to fit the plot interval by skipping 
values.  The F D keyboard sequence lets you apply an averaging filter to the 
displayed plot data.  The value is the number of queue values to average.

You can scroll around the plot queue data from the keyboard (arrow keys, page 
up/down, home, end, etc) or with the mouse (left button hold at the center of 
the plot area, move the mouse to the left or right of center to scroll left or 
right,  the farther the mouse is from the center of the plot, the faster it 
scrolls).

Normally Lady Heather scrolls the plot to the left automatically, but if you 
are reviewing plot data, the scrolling is suspended (press DEL to resume normal 
scrolling plot displays).

You can set/remove up to 10 markers with the = and - keys.  To go to a marker, 
press it's number.  You can jump to the next anomaly (like time stamp skips - 
show with a red tick at the top of the plot) with the % key.

Normally Lady Heather auto-scales and centers the plots (indicated by a '~' in 
the REF (center line value) and scale (units/div) values above the plots.  You 
can set fixed reference and/or scale factors (indicated by an '=' in the REF 
and scale factor values via the G keyboard menus.  There are also options for 
changing things like what statistics (AVG/RMS/MAX/MIN/SPAN, etc) to show, plot 
colors, etc)  These can be changed globally for all plots or individually for 
each plot.

You can also have Lady Heather do an FFT of a given plot.

You can do a screen dump of just the plot area (W G command) or write an ascii 
log file of the shown plot area values (W P).  The next version of Lady Heather 
also supports writing logs in XML, KML, or GPG file formats. You can also do 
automatic screen or log dumps on a periodic basis from the T keyboard menu or 
the command line.


--

>  Pardon my lack of knowledge regarding Lady Heather, what is the x-axis
scale?
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Re: [time-nuts] HP-105B Battery Replacement?

[David]

High end standby UPSes support external batteries but most or all
online UPSes do.  I have 3 different online UPS models and they all
support external batteries of either 48 or 60 volts.

On Thu, 15 Sep 2016 15:13:59 -0700, you wrote:

>Since I have a 12V 100 A-H gelled electrolyte battery as a
>short-term backup (for those outages not worth firing up the generator),
>I'd like to find a UPS that uses an external battery. So far I don't see
>such a thing--do they exist?
>
>Jeremy
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Re: [time-nuts] A new take on the all-hardware GPSDO concept

[Lars Walenius]

Hi Nick,

Jim Millers design is very clever and as I see can give results as good as a 
digital approach but it has the same limitations:
The GPS jitter and the oscillator jitter in combination with the loop bandwidth.

The only ADEV I have seen for the Miller GPSDO is this one  
http://www.leapsecond.com/pages/gpsdo/  .
Can anyone point me to other tests?

The ADEV I see on leapsecond.com indicates for me a time constant of around 
200seconds. That is what you get with a OCXO range of 0.25ppm. You don´t need 
to have a large RC-filter. The original R1-C1 time constant with 16 seconds 
time constant will work as long as the internal oscillator in the Jupiter-T is 
at least some Hz away from a multiple of 10kHz. If that is true the sawtooth 
out of the Jupiter will have enough high frequency to be easily filtered by the 
RC. This is of course a risk. See for example: 
https://www.febo.com/pipermail/time-nuts/2005-August/019106.html . If you get a 
hanging bridge you have at least as much trouble as a non sawtooth corrected 
GPSDO and probably much worse as the RC filter is only 16s. In the digital 
approach the prefilter may filter away the hanging bridge (in best case).

As I understand the Miller GPSDO with a OCXO with a 0.25ppm range and 10kHz 
into an XOR phase detector and 16s RC will be very similar to a digital 
approach with a TIC (Time interval counter ) with +-25us range followed by a 
prefilter with time constant 16s and a loop with just the P-term with a time 
constant of 200secs. As it has no I-term it will have slightly less noise but 
the output phase will drift as soon as the OCXO drifts (as a FLL). The 
resolution of the XOR phase detector (TIC) will be limited by the noise but as 
0.1mV is 1ns the resolution can be seen as better than 1ns is my conclusion. A 
problem might be that the output of the XOR drifts with the 5V supply but this 
can be seen as the same problem as the DAC drift in a digital approach.

My conclusion (without testing) is that the Jupiter-T 10kHz is very good but 
not better than the sawtooth corrected outputs from M12 or LEA6T receivers. 
That is the ADEV can be approximated by 1E-9/Tau (1E-12 at 1000s) in good 
conditions.

My experience with the Venus838-T is only 2 weeks but disappointing. This can 
also be guessed from the datasheet ADEV curve, that I guess is sawtooth 
corrected values as it starts at 3E-9 at 1s, but is only 1E-11 at 1000s a 
factor 10 worse than I get with the LEA-6T with the same antenna and setup. If 
anyone have ADEV-MDEV curves to share I would be glad to see what can be 
achieved with the venus838-T. My conclusion is also that sawtooth correction is 
useless on my 838-T.

Lars


>Nick wrote:

>Jim Miller's 10 kHz GPSDO that’s been referenced here has either solved this 
>problem, or the 10 kHz output of the >Jupiter is substantially better than the 
>Venus’ 10 MHz output, or the design doesn’t give the results time-nuts expect 
>>from a GPSDO. Which of those applies?


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Re: [time-nuts] Jim Miller simple GPSDO

[jimlux]

On 9/16/16 12:07 PM, Lars Walenius wrote:

Interesting. Maybe not the optimum oscillator for a GPSDO.

Lars



Från: Tim Shoppa

Skickat: den 14 september 2016 14:39


There are special "wide-pull-range" VCXO's where a 10MHz unit will indeed
have sensitivity of 600Hz/V or more. e.g.
http://www5.epsondevice.com/en/products/vcxo_standard/vg4231ca.html

I don't know exactly what Epson does inside that particular unit, but a
trick to get wide pull range with discrete circuits is to put two or more
crystals in parallel.

Tim N3QE


On Wed, Sep 14, 2016 at 4:40 AM, Lars Walenius 

wrote:


The VCXO sensitivity given is strange as it indicates a far to wide span
so I guessed 30ppm and if it is higher it still needs the damping from
R2-C2.
For the OCXO I used the figures given. With 2Hz per volt and 8 Volt span
you have 16Hz of span. 16Hz divided with 10MHz is 1.6ppm (parts per
million) can also be said as 1.6us/s.




At JPL, we tried with middling success to build a DRO with two 
varactors: one loosely coupled with low tuning gain (for phase locking), 
one tightly coupled with high tuning gain (for coarse frequency selection).


The idea was to get away from "individually hand crafted" oscillators 
for deep space transponders.  Right now, you need to know your channel 
assignment a couple years in advance so you can get the DRO tuned for 
your channel (puck movement, tuning screw, etc), as well as getting the 
reference crystal cut/selected for the right base frequency to multiply up.


This raises a problem when you want to use a spare transponder from 
Mission A (which has already launched) for Mission B.  Aside from having 
multiple spacecraft at the same frequency, it raises a big issue if you 
have a dual string architecture.. you'd like the prime and redundant to 
have the same channel assignment.


We were able to do it, sort of, but we were still subject to all the 
ills of a DRO in a mechanical cavity.  Microphonics, for instance. Not 
an issue in space, which is very, very, very quiet, but a real pain on 
the ground when you're testing.


As it happens, NCO/DAC technology has advanced to the point where we can 
lock a wider band VCO well enough.  And NCOs let you be "crystal 
frequency independent".


Now we can buy a really high quality rock at 10.0something MHz (or 
use a spare USO from another mission) and use it to lock a wider band VCO.




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Re: [time-nuts] 53132A triggering

[John Ackermann N8UR]

Thanks, Bob.  I just tried that and got solid results.  One nice thing about 
the 5370 vs this newer stuff is that the knobs and switches stay in the same 
place through power cycles!

> On Sep 16, 2016, at 1:21 PM, Bob Camp  wrote:
> 
> Hi
> 
> Set it to:
> 
> 1) DC coupled (AC does not go low enough)
> 2) 50 ohms if your driving source will tolerate it, otherwise 1 meg ohm.
> 3) Manual trigger mode (Auto is to fast and it forgets where the trigger 
> should be)
> 4) Trigger level around 1/2 the PPS P-P voltage
> 
> Once set up that way, the triggering should be pretty solid. There is still 
> the wonderful stuff about pulses that 
> arrive on top of each other ….
> 
> Bob
> 
>> On Sep 16, 2016, at 1:10 PM, John Ackermann N8UR  wrote:
>> 
>> I'm fairly new to driving the 53132 and it seems to be quite a pain to set 
>> up reliable triggering for TTL-level pulses (e.g., PPS).  Simply leaving it 
>> to auto-trigger sure doesn't do the trick.  Any suggestions on optimum 
>> trigger settings for this use?
>> 
>> Thanks!
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Re: [time-nuts] Jim Miller simple GPSDO

[Lars Walenius]

Interesting. Maybe not the optimum oscillator for a GPSDO.

Lars


>Från: Tim Shoppa
Skickat: den 14 september 2016 14:39


There are special "wide-pull-range" VCXO's where a 10MHz unit will indeed
have sensitivity of 600Hz/V or more. e.g.
http://www5.epsondevice.com/en/products/vcxo_standard/vg4231ca.html

I don't know exactly what Epson does inside that particular unit, but a
trick to get wide pull range with discrete circuits is to put two or more
crystals in parallel.

Tim N3QE

>>On Wed, Sep 14, 2016 at 4:40 AM, Lars Walenius 
wrote:

> The VCXO sensitivity given is strange as it indicates a far to wide span
> so I guessed 30ppm and if it is higher it still needs the damping from
> R2-C2.
> For the OCXO I used the figures given. With 2Hz per volt and 8 Volt span
> you have 16Hz of span. 16Hz divided with 10MHz is 1.6ppm (parts per
> million) can also be said as 1.6us/s.
>
> Lars
>

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Re: [time-nuts] Lady Heather's plotting functions

[Scott Stobbe]

The joys of a small display, why couldn't I see that. Many thanks Mark &
Peter.

Soon to be the emac's of gpsdo's (in the good, can do anything sense) well
done.



On Wed, Sep 14, 2016 at 12:27 AM, Mark Sims  wrote:

> You can set the view interval to any value with the "V" keyboard command
> (default is one second per pixel, 1 minute per horizontal division).
>
> Above the plot area is a section that give the view interval in total time
> (60 minutes in those plots) and time per division (5 minutes per
> division).   Lady Heather logs all the data in a circular buffer and when
> it fills, the oldest data is replaced by newer data).The default plot
> queue size is 3 days... the /q command line option for can change that
> (n.b.  and error in the help screen says the default is 30 days).
>
> Lady Heather decimates the queue data to fit the plot interval by skipping
> values.  The F D keyboard sequence lets you apply an averaging filter to
> the displayed plot data.  The value is the number of queue values to
> average.
>
> You can scroll around the plot queue data from the keyboard (arrow keys,
> page up/down, home, end, etc) or with the mouse (left button hold at the
> center of the plot area, move the mouse to the left or right of center to
> scroll left or right,  the farther the mouse is from the center of the
> plot, the faster it scrolls).
>
> Normally Lady Heather scrolls the plot to the left automatically, but if
> you are reviewing plot data, the scrolling is suspended (press DEL to
> resume normal scrolling plot displays).
>
> You can set/remove up to 10 markers with the = and - keys.  To go to a
> marker, press it's number.  You can jump to the next anomaly (like time
> stamp skips - show with a red tick at the top of the plot) with the % key.
>
> Normally Lady Heather auto-scales and centers the plots (indicated by a
> '~' in the REF (center line value) and scale (units/div) values above the
> plots.  You can set fixed reference and/or scale factors (indicated by an
> '=' in the REF and scale factor values via the G keyboard menus.  There are
> also options for changing things like what statistics
> (AVG/RMS/MAX/MIN/SPAN, etc) to show, plot colors, etc)  These can be
> changed globally for all plots or individually for each plot.
>
> You can also have Lady Heather do an FFT of a given plot.
>
> You can do a screen dump of just the plot area (W G command) or write an
> ascii log file of the shown plot area values (W P).  The next version of
> Lady Heather also supports writing logs in XML, KML, or GPG file formats.
> You can also do automatic screen or log dumps on a periodic basis from the
> T keyboard menu or the command line.
>
>
> --
>
> >  Pardon my lack of knowledge regarding Lady Heather, what is the x-axis
> scale?
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Re: [time-nuts] HP-105B Battery Replacement?

[Jeremy Nichols]

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Re: [time-nuts] HP-105B Battery Replacement?

[Brooke Clarke]

Hi David:

The chemistries are very different. Ni-Cad is endothermic whereas Ni-MH is Exothermic.  This is why chargers for Ni-MH 
have a mandatory temperature sensor.  This is one of the reasons I say Ni-Cad cells batteries are easy to charge.


--
Have Fun,

Brooke Clarke
http://www.PRC68.com
http://www.end2partygovernment.com/2012Issues.html
The lesser of evils is still evil.

 Original Message 
NiMH batteries are close the same voltage and charge the same as NiCd and are more available and not toxic when 
disposing of them. They should be a good replacement.  Lithiums are very different in voltage and charging.


David N1HAC

On 9/14/16 10:19 PM, Jeremy Nichols wrote:

Thanks, Brooke, I'll price new Ni-Cads. I wasn't thinking of lead-acid (gel
cells) but rather lithium rechargeable, providing I can find a type that
won't catch fire and will work with the 105B'scircuits.

Jeremy


On Wednesday, September 14, 2016, Brooke Clarke  wrote:


Hi Alex:

Yes, I'm recommending Ni-Cad but NOT any acid type.

--
Have Fun,

Brooke Clarke
http://www.PRC68.com
http://www.end2partygovernment.com/2012Issues.html
The lesser of evils is still evil.

 Original Message 


Hi Brooke,

sorry I have to disappoint you; Ni-Cd batteries do not use any acid, they
have K-OH  kalium hidrioxid  [potassium hydroxide  for anglophone ] as
electrolyte and they are normally very air-tide, and widely used in radios.

73

KJ6UHN

Alex

On 9/14/2016 4:45 PM, Brooke Clarke wrote:


Hi Jeremy:

It's a very bad idea to put any battery with acid in an enclosure that
has electronics since if it vents the acid will etch the PCBs.
Guess how I learned this.  I got a great price on a Gibbs Frequency
Standard because the oven no longer worked.
http://prc68.com/I/office_equip.html


Modern Ni-Cad batteries have much more capacity than older ones and no
longer have a memory effect.  They are also very easy to charge, so why not
just replace the old cells?



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Re: [time-nuts] 53132A triggering

[Bob Camp]

Hi

Set it to:

1) DC coupled (AC does not go low enough)
2) 50 ohms if your driving source will tolerate it, otherwise 1 meg ohm.
3) Manual trigger mode (Auto is to fast and it forgets where the trigger should 
be)
4) Trigger level around 1/2 the PPS P-P voltage

Once set up that way, the triggering should be pretty solid. There is still the 
wonderful stuff about pulses that 
arrive on top of each other ….

Bob

> On Sep 16, 2016, at 1:10 PM, John Ackermann N8UR  wrote:
> 
> I'm fairly new to driving the 53132 and it seems to be quite a pain to set up 
> reliable triggering for TTL-level pulses (e.g., PPS).  Simply leaving it to 
> auto-trigger sure doesn't do the trick.  Any suggestions on optimum trigger 
> settings for this use?
> 
> Thanks!
> ___
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Re: [time-nuts] HP-105B Battery Replacement?

[Bob Camp]

Hi

Any time you get into UPS designs, they are all over the map …

> On Sep 16, 2016, at 1:01 PM, Gary E. Miller  wrote:
> 
> Yo Hal!
> 
> On Fri, 16 Sep 2016 00:50:56 -0700
> Hal Murray  wrote:
> 
>> g...@rellim.com said:
>>> APC UPS can't handle the longer runtime, but never had a problem
>>> with any version of CyberPower.   
>> 
>> There are two parameters for UPS boxes.  One is the power the
>> electronics can handle.  The other is the amount of energy the
>> batteries can hold.
> 
> You can change up the batteries for more runtime, but real cheap UPS
> will overheat and die.  They were not designed for steady state
> operation.
> 
> That is the problem with the cheaper APC.  They were designed for 5 or
> 10 mins at max power.  Run them for two hours at max power then they
> overheat and permanently fail.
> 
>> I think some of the smaller units have inadequate cooling to run at
>> rated power for long, but their batteries are small enough so that
>> they run out of power before the electronics overheats.
> 
> Nothing to do with size.  I have seen this in big and small.
> 
> The other thing is whether there is a transfer switch, or the UPS is on
> continuously.  The APC tend to switch the batteries and DC/AC converter
> online only when needed.  OTOH, the CyberPower run from the batteries
> all the time.  

Certainly some do. The ones I have do not. You take a pretty significant 
efficiency hit when you go “full time DC”. 

Bob

> The transfer glitch can be quite large and affect the
> load.  So the float type UPS tends to give smoother power more of the
> time.
> 
> RGDS
> GARY
> ---
> Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703
>   g...@rellim.com  Tel:+1 541 382 8588
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[time-nuts] 53132A triggering

[John Ackermann N8UR]

I'm fairly new to driving the 53132 and it seems to be quite a pain to set up 
reliable triggering for TTL-level pulses (e.g., PPS).  Simply leaving it to 
auto-trigger sure doesn't do the trick.  Any suggestions on optimum trigger 
settings for this use?

Thanks!
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Re: [time-nuts] HP-105B Battery Replacement?

[Gary E. Miller]

Yo Hal!

On Fri, 16 Sep 2016 00:50:56 -0700
Hal Murray  wrote:

> g...@rellim.com said:
> > APC UPS can't handle the longer runtime, but never had a problem
> > with any version of CyberPower.   
> 
> There are two parameters for UPS boxes.  One is the power the
> electronics can handle.  The other is the amount of energy the
> batteries can hold.

You can change up the batteries for more runtime, but real cheap UPS
will overheat and die.  They were not designed for steady state
operation.

That is the problem with the cheaper APC.  They were designed for 5 or
10 mins at max power.  Run them for two hours at max power then they
overheat and permanently fail.

> I think some of the smaller units have inadequate cooling to run at
> rated power for long, but their batteries are small enough so that
> they run out of power before the electronics overheats.

Nothing to do with size.  I have seen this in big and small.

The other thing is whether there is a transfer switch, or the UPS is on
continuously.  The APC tend to switch the batteries and DC/AC converter
online only when needed.  OTOH, the CyberPower run from the batteries
all the time.  The transfer glitch can be quite large and affect the
load.  So the float type UPS tends to give smoother power more of the
time.

RGDS
GARY
---
Gary E. Miller Rellim 109 NW Wilmington Ave., Suite E, Bend, OR 97703
g...@rellim.com  Tel:+1 541 382 8588


pgpSuqjJp86Wj.pgp
Description: OpenPGP digital signature
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[time-nuts] HP-105B Manual

[Jeremy Nichols]

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Re: [time-nuts] HP-105B Battery Replacement?

[Scott McGrath]

Actually the larger SmartUPS series can run for hours providing a large enough 
battery string is available I have a SmartUPS RM3000 running data rack this 
has 2 external battery boxes and will run everything for 6 hours.


For TimeNuts applications though I'd recommend a Liebert UPS as this is a 
'online' UPS as in input is converted to DC and used to float batteries and 
drive a power oscillator for a true sine output and in a power interruption 
there is no transfer time or transients on the output

Content by Scott
Typos by Siri

> On Sep 16, 2016, at 3:50 AM, Hal Murray  wrote:
> 
> 
> g...@rellim.com said:
>> APC UPS can't handle the longer runtime, but never had a problem with any
>> version of CyberPower.
> 
> There are two parameters for UPS boxes.  One is the power the electronics can 
> handle.  The other is the amount of energy the batteries can hold.
> 
> I think some of the smaller units have inadequate cooling to run at rated 
> power for long, but their batteries are small enough so that they run out of 
> power before the electronics overheats.
> 
> -- 
> These are my opinions.  I hate spam.
> 
> 
> 
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Re: [time-nuts] HP-105B Battery Replacement?

[Hal Murray]

g...@rellim.com said:
> APC UPS can't handle the longer runtime, but never had a problem with any
> version of CyberPower. 

There are two parameters for UPS boxes.  One is the power the electronics can 
handle.  The other is the amount of energy the batteries can hold.

I think some of the smaller units have inadequate cooling to run at rated 
power for long, but their batteries are small enough so that they run out of 
power before the electronics overheats.

-- 
These are my opinions.  I hate spam.



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Re: [time-nuts] HP-105B Battery Replacement?

[Jeremy Nichols]

Thanks, everyone for the ideas and discussion. One sine wave inverter sold
by theinverterstore.com is a "
*AIMS 1200 Watt Inverter with Transfer SwitchPart # PWRIX120012S." *

It sounds more than adequate for my needs. I'm sure there are others and
I'll continue to shop.

Jeremy

On Thursday, September 15, 2016, Robert LaJeunesse 
wrote:

> Check with the used equipment / property disposition department of the
> nearest big research university. The one near me often has big UPSs at
> relatively little prices.
>
> Bob LaJeunesse
>
> > Sent: Thursday, September 15, 2016 at 7:12 PM
> > From: "Andy ZL3AG" >
> > To: "Discussion of precise time and frequency measurement" <
> time-nuts@febo.com >
> > Subject: Re: [time-nuts] HP-105B Battery Replacement?
> >
> >
> > If you know where to get them from, you can get used 19" rack mount
> UPS's for scrap value. They might have fried batteries, but that's easily
> solved.
> >
> >
> > On 16/09/2016, at 11:06 AM, Bob kb8tq wrote:
> >
> > > Hi
> > >
> > > They are very common when you look at server UPS or larger units.
> There are literally hundreds of models to pick between. Prices are from
> roughly $400 up to a few hundred thousand dollars per unit.
> > >
> > > Bob
> >
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