[time-nuts] Lady Heather for Z3801A

[Larry McDavid]

Does Lady Heather software support the HP Z3801A GPSDO? I recently read 
that it supports "most GPS receivers" but I have not heard that it 
supports the Z3801A. It would be great if it can do this...


--
Best wishes,

Larry McDavid W6FUB
Anaheim, California  (SE of Los Angeles, near Disneyland)
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[time-nuts] Lady Heather's Tbolt oscillator auto-tune function

[Mark Sims]

Here is a plot of the Thunderbolt cold starting with the "initial DAC voltage" 
setting set to the peak value of the initial spike (and not the 10.00 MHz 
setting).   The upward spike when the unit starts tracking sats (it took around 
twice as long to start tracking sats) is gone, but the DAC voltage had a new 
little glitch in the curve when it started disciplining the oscillator.  Once 
the disciplining got underway,  not much was different between the three 
different initial DAC voltage settings.

General conclusions...  the initial DAC voltage setting does not affect the 
overall disciplining, but can affect the time it takes to start tracking sats.  
 Your best initial DAC voltage setting is probably at the 10.00 MHz point 
that the auto-tune function uses.
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Re: [time-nuts] HP 105B Battery the saga continues

[Jeremy Nichols]

How did you come up with the 33,000 uF number, Perry, and is it one big 
capacitor or lots of little ones tied together? The big cap will also 
filter out some of the remaining ripple in the power supply that may 
have been managed by the ni-cad battery.


Jeremy


On 9/17/2016 3:50 PM, Perry Sandeen via time-nuts wrote:


  Where the nicad pack was located one can put in 33,000 uF of Nichicon 105C caps for 
$20 for a buffer hold over. 


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[time-nuts] HP 105B Battery the saga continues

[Perry Sandeen via time-nuts]

Hi,
The battery problem becomes more convoluted every day. Due to family medical 
issues I have not been able to do any testing/repairing.

The 105B charger is set up for nicads using some selected un-alterable charging 
rate so to use an internal lead acid setup requires a different ps.

My unit prefixed 2128A has a pc board non-adjustable ps that requires a 
different extender board to trouble shoot with the power on than the other 
boards require. Mine partially works as I have oven power but a current limited 
other voltages so I have to either buy the special extender board or rebuild 
the ps. Since I'm never going to use NiCads rebuilding the ps is a very viable 
option.

My other unit has the older style ps with a heat-sinked pass transistor mounted 
to the chassis. At present it in in the equipment rack and cooking nicely.
A number of battery back-up proposals have been shared, many are case specific.
In my situation here in So CA are rare occasional fractions of a second drop 
outs. I purchase a refurbished APC Pro 1500 for $100 delivered from ebay.
IF I get aroundtoit, the least expensive option for me is a 12 car battery and 
a buck-boost converter from china for $8 and use a trickle charger [Harbor 
Freight] to keep it topped off. I'd use a Shottky barrier diode for isolation 
from the ac ps and not use a relay to switch over. 
 Where the nicad pack was located one can put in 33,000 uF of Nichicon 105C 
caps for $20 for a buffer hold over. The oscillator draw is listed at 18W.  If 
I have a power outage for several days my 105B will be the least of my problems.
I've cobbled together a 105B manual for the 2128A prefix only using the errata 
sheet and some ski's from a list member who I apologize to for forgetting his 
name for attribution. It is 75 Mbytes in MS word and I have to re-install my 
PDF creator so I can get it to a size that will fit my attachment limit.  
Although not complete it is a pretty good start.
The wiring method is the weirdest I've seen any time in my electronics career. 
The underside of all the pc board edge connectors are covered with a 
non-removable aluminium plate, so one has to probe through the top. It is the 
hardest piece of HP equipment that I've had to work on in 25 years of working 
on HP equipment.
The divider boards can easily replaced by TTL logic and a 10 MHz output jack 
can be added. Great oscillator but horrid implementation.
Regards,
Perrier











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

[Brooke Clarke]

Hi Attila:

The difference in chemistry I got from "Handbook of Batteries" 3rd ed, 2001.  Your comments about modern chargers are 
correct, but this thread is about the HP 105 which uses what we both might call an old fashioned charging circuit.


--
Have Fun,

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

 Original Message 

On Fri, 16 Sep 2016 11:37:23 -0700
Brooke Clarke  wrote:


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.

Both NiCd and NiMH behave the same way chemically. Both reactions
are exotherm when the batteries are full, i.e. the electrical
energy you put into them cannot be "absorbed" chemically and thus
is dissipated through heat. (I'm not sure whether it's correct to
talk about exotherm/endotherm in this kind of setting, i'd appreciate
if someone with chemistry knowledge would correct me) The reason why
NiMH charger "need" a temeperature sensor is, because the classical
fast-charger for NiCd uses the negative dV/dt slope when the battery
gets full to detect end of charging, but the peak is much less
pronounced with NiMH than with NiCd (factor 2-5 IIRC). Hence people
were adviced to use only NiCd fast-chargers which had a temperature sensor.
Slow chargers (i.e. 0.1C chargers) do not have this problem, though
you shouldn't leave the battery  on for days (NiMH is a quite bit more
sensitive when it comes to overcharging). "Modern" fast-chargers for
NiCd/NiMH  chemistries have adjusted their dV/dt trip point to reliably
trigger with NiMH. Additionally all better chips (probably all chips, today?)
use pulse charging where the battery is measured during a short no-charge
period to more accurately measure the batteries condition.


NiMH is a good replacement for NiCd if you can live with the drawbacks.
Namely:
* slightly trickier charging (but that's the problem of the charger)
* more sensitive to over/under charging
* higher self-discharge

On the positive side, you get a greatly reduced memory effect (to the
point where a lot of people say it doesn't exist).

Attila Kinali



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

[David]

I would not use such a narrow pulse for any of those reasons except
for power if that was an issue.  I would and have however used narrow
pulses simply because it allows for a lower volt*time product on a
transformer.

On Fri, 16 Sep 2016 21:03:12 -0400, you wrote:

>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
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Re: [time-nuts] 53132A triggering

[Scott Stobbe]

Well I have looked into this before for the 53131A, and the way signal peak
volts is implemented is bizarre. I say bizarre because for low frequency,
low duty cycle signals (like PPS) the 53131A will at times report the lower
peak as being higher than the upper peak...

>From the 53131A Manual:
 Peak volts (53131A, 53132A, 53181A) Measurement is specified on
Channels 1 and 2 for dc signals; or for ac signals of frequencies between
100 Hz and 30 MHz with peak-to-peak amplitude greater than 100 mV.

 Results range –5.1 V to +5.1 V
 Resolution 10 mV Peak volts systematic
 uncertainty for ac signals: 25 mV + 10% of V
 for dc signals: 25 mV + 2% of V

Well, I read the specification as being guaranteed for any DC coupled
signal, in my experience even DC signals with a frequency less than 100 Hz
fail to register correctly.

As an example at 1 kHz (10% duty cycle) the channel 1 VPP (DC, 50 Ohm),
behaves as expected:
 +0.00V +1.58V
 +0.01V +1.58V
 +0.01V +1.58V
 +0.00V +1.58V
 +0.00V +1.58V
 +0.00V +1.58V
 +0.00V +1.58V
 +0.01V +1.58V
 +0.00V +1.58V
 +0.00V +1.58V
 +0.01V +1.58V
 +0.00V +1.58V
 +0.00V +1.58V
 +0.01V +1.58V
 +0.00V +1.58V
 +0.00V +1.58V
 +0.00V +1.58V
 +0.01V +1.58V
 +0.00V +1.58V
 +0.01V +1.58V
 +0.00V +1.58V
 +0.00V +1.58V
 +0.00V +1.58V
 +0.00V +1.58V
 +0.01V +1.58V
 +0.00V +1.58V
 +0.00V +1.58V

For 1 Hz (10% duty cycle) the channel 1 VPP (DC, 50 Ohm), behaves
unexpectedly:
 +0.05V +0.05V
 +0.05V +0.05V
 +0.06V +1.28V
 +0.05V +0.05V
 +0.05V +0.05V
 +0.05V +0.08V
 +1.28V +0.05V  <- Lower peak greater than upper peak
 +0.05V +0.05V
 +0.05V +0.05V
 +0.05V +1.54V
 +0.05V +0.05V
 +0.05V +0.05V
 +0.05V +0.05V
 +1.24V +0.05V <- Lower peak greater than upper peak
 +0.05V +0.05V
 +0.05V +0.05V
 +0.05V +0.64V
 +0.05V +0.05V
 +0.05V +0.05V
 +0.05V +0.05V
 +0.06V +1.28V


So the reason auto-trigger fails, is the instrument does not set an
appropriate trigger level, since the VPP reading fail to have any integrity
below 100 Hz.

I would be interested to see what you get on the 53132, I suspect its
implementation of VPP to have the same issues.


On Sat, Sep 17, 2016 at 10:28 AM, Bob Camp  wrote:

> Hi
>
> Set it up on your 53132 and see what happens …
>
> Bob
>
> > On Sep 16, 2016, at 8:35 PM, Scott Stobbe 
> wrote:
> >
> > 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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> >> mailman/listinfo/time-nuts
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Re: [time-nuts] Why are PPS pulses so narrow? (was: 53132A triggering)

[Peter Vince]

Thanks guys - interesting answers all!

 Peter


On 17 September 2016 at 18:00, Chris Albertson 
wrote:

> On Fri, Sep 16, 2016 at 4:44 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.
> >
>
>  None of us can guess the original designer's motivation but...
>
> I think you answered your own question "far less obvious if you trigger off
> the wrong edge.".For most cases, except for time nuts, a few
> microseconds does not matter.  So the GPS PPS works almost as good if you
> invert the signal and trip off the wrong edge.   Yes it makes such a
> mistake hard to find but, I think that was the point.
>
>
>
> --
>
> Chris Albertson
> Redondo Beach, California
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Re: [time-nuts] Why are PPS pulses so narrow? (was: 53132A triggering)

[Chris Albertson]

On Fri, Sep 16, 2016 at 4:44 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.
>

 None of us can guess the original designer's motivation but...

I think you answered your own question "far less obvious if you trigger off
the wrong edge.".For most cases, except for time nuts, a few
microseconds does not matter.  So the GPS PPS works almost as good if you
invert the signal and trip off the wrong edge.   Yes it makes such a
mistake hard to find but, I think that was the point.



-- 

Chris Albertson
Redondo Beach, California
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Re: [time-nuts] 53132A triggering

[Bob Camp]

Hi

Set it up on your 53132 and see what happens …

Bob

> On Sep 16, 2016, at 8:35 PM, Scott Stobbe  wrote:
> 
> 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] HP-105B Battery Replacement?

[Attila Kinali]

On Sat, 17 Sep 2016 12:03:47 +0200
Attila Kinali  wrote:

> Hence people
> were adviced to use only NiCd fast-chargers which had a temperature sensor. 

Addendum: The other "classical" NiCd fast-charger architecture used
the fast rise in temperature when the battery was full to detect
end of charge. These reliably triggered with NiMH as well, although
had a tendency to slightly overcharge them.

Attila Kinali

-- 
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Any simple idea will be worded in the most complicated way.
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Re: [time-nuts] HP-105B Battery Replacement?

[Attila Kinali]

On Fri, 16 Sep 2016 11:37:23 -0700
Brooke Clarke  wrote:

> 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.

Both NiCd and NiMH behave the same way chemically. Both reactions
are exotherm when the batteries are full, i.e. the electrical
energy you put into them cannot be "absorbed" chemically and thus
is dissipated through heat. (I'm not sure whether it's correct to
talk about exotherm/endotherm in this kind of setting, i'd appreciate
if someone with chemistry knowledge would correct me) The reason why
NiMH charger "need" a temeperature sensor is, because the classical
fast-charger for NiCd uses the negative dV/dt slope when the battery
gets full to detect end of charging, but the peak is much less
pronounced with NiMH than with NiCd (factor 2-5 IIRC). Hence people
were adviced to use only NiCd fast-chargers which had a temperature sensor. 
Slow chargers (i.e. 0.1C chargers) do not have this problem, though
you shouldn't leave the battery  on for days (NiMH is a quite bit more
sensitive when it comes to overcharging). "Modern" fast-chargers for
NiCd/NiMH  chemistries have adjusted their dV/dt trip point to reliably
trigger with NiMH. Additionally all better chips (probably all chips, today?)
use pulse charging where the battery is measured during a short no-charge
period to more accurately measure the batteries condition.


NiMH is a good replacement for NiCd if you can live with the drawbacks.
Namely:
* slightly trickier charging (but that's the problem of the charger)
* more sensitive to over/under charging
* higher self-discharge

On the positive side, you get a greatly reduced memory effect (to the
point where a lot of people say it doesn't exist). 

Attila Kinali

-- 
Malek's Law:
Any simple idea will be worded in the most complicated way.
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Re: [time-nuts] HP-105B Battery Replacement?

[David G. McGaw]

It has been my experience that both chemistries have thermal cutouts for 
overcharge limiting and both can use chargers that detect the negative 
voltage slope when the cells heat up once they are fully charged, hence 
the ability to use the same chargers for NiCd and NiMH.  I have many 
radios that started out with NiCd batteries and the newer replacements 
are NiMH.


David

On 9/16/16 2:37 PM, Brooke Clarke wrote:

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.




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