Re: [time-nuts] Anybody want a Thunderbolt power supply

[Charles Steinmetz]

Dave wrote:


Getting the required Thunderbolt supply rails from a nominal 12v dc
supply of doubtful cleanliness is an issue that also needs to be
addressed.  I'm still mulling over that one. (and using a triple output
switcher from an inverter backed mains supply meantime!)
The ex-telco GPSDOs all run on a nominal 24-50 volt DC supply but I
don't know how they generate their internal supplies. I suspect switchers?


Yes, they typically have two or three flat-pack DC-DC converters inside. 
 I have converted a number of them by replacing the DC-DC converters 
and feeding the circuitry from a mains-operated linear DC supply 
(usually because one or more of the DC-DC converters was fried and I saw 
it as a golden opportunity rather than a problem of locating spare 
converters of invariably questionable provenance).


Best regards,

Charles


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Re: [time-nuts] Anybody want a Thunderbolt power supply

[Bruce Griffiths]

It will show up if the value of the voltage setting bypass capacitor is 
reduced. Both the Johnson and excess noise in this resistor coupled with the 
current source flicker noise should become evident. The datasheet graphs 
indicate that the Johnson noise of the voltage setting resistor(33k2 
~22nV/rtHz) isn't significant in comparison with other sources.

Bruce
 

On Thursday, 1 September 2016 5:56 PM, Gerhard Hoffmann  
wrote:
 

 Am 01.09.2016 um 06:07 schrieb Bruce Griffiths:
> I have a quad LT3042 PCB that I must get around to assembling.One potential 
> issue with the LT3042 is the relatively high noise at low frequencies when 
> the capacititve bypassing of the resistor that sets the output voltage is 
> ineffective.

I wonder where that relatively high noise on the LT3042 might hide.

< 
https://www.flickr.com/photos/137684711@N07/24070698809/in/datetaken/lightbox/ 
 >

That is maybe 3 nV/RT Hz at 10 Hz, and the limit is probably not the 
LT3042 but
the GR-like noise of my old preamp below 30 Hz. (rises faster than 1/f)
Remember that 0 dB in the plot is 1 nV rt Hz, which is the equivalent 
INPUT noise voltage
of an AD797 or LT1028.

The LT4042 measurement was taken from an ugly dead bug ad-hoc construction.
Deviating from the 4.7u output cap produces some noise peaks @ > 100 KHz.
(but still 30 dB better than the others)
More is less here.

regards, Gerhard



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Re: [time-nuts] Anybody want a Thunderbolt power supply

[Charles Steinmetz]

Bruce wrote:


Low noise regulators for the +12V and +5V outputs would also be useful.


Very true.  By focusing on the -12v supply, I did not intend to suggest 
that low noise is unimportant on the +12v and +5v supplies.


The suggestion to use LT3042s is a good one, but note that it has an 
output current rating of 200mA.  The Tbolt needs ~250mA at +5v, and 
~700mA at +12v [at startup -- but only ~150mA steady-state, depending on 
ambient temperature].  LT3042s can be used in parallel, so two of them 
for the +5v supply and four of them for the +12v supply would be 
required.  That isn't so bad for the +5v supply, but seems excessive for 
the +12v supply (particularly when three of the four are needed only 
during warmup from cold).


The LT3088 and LT3080 will deliver 800mA and 1.1A, respectively, with 
low noise (but not as low as the LT3042).  One of those might be a 
better choice for the +12v supply.  Similarly, the LT3085 can deliver 
500mA, so one of those could be used for the +5v supply.


Finally: Linear Technology -- Where is our negative-voltage complement 
to the LT3042?


Best regards,

Charles


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Re: [time-nuts] Anybody want a Thunderbolt power supply

[Gerhard Hoffmann]

Am 01.09.2016 um 05:35 schrieb Charles Steinmetz:


The suggestion to use LT3042s is a good one, but note that it has an 
output current rating of 200mA.  The Tbolt needs ~250mA at +5v, and 
~700mA at +12v [at startup -- but only ~150mA steady-state, depending 
on ambient temperature].  LT3042s can be used in parallel, so two of 
them for the +5v supply and four of them for the +12v supply would be 
required.  That isn't so bad for the +5v supply, but seems excessive 
for the +12v supply (particularly when three of the four are needed 
only during warmup from cold).



I have made a stamp-sized layout for LT3042 + external npn power transistor
as shown in the data sheet.
Not fabricated, let alone tested.

The LT3088 and LT3080 will deliver 800mA and 1.1A, respectively, with 
low noise (but not as low as the LT3042).  One of those might be a 
better choice for the +12v supply.  Similarly, the LT3085 can deliver 
500mA, so one of those could be used for the +5v supply.


Finally: Linear Technology -- Where is our negative-voltage complement 
to the LT3042?


Yes, that is badly missing.

regards, Gerhard
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Re: [time-nuts] Anybody want a Thunderbolt power supply?

[DaveH]

Someone could come out with a circuit board for a single configurable
voltage and decent noise specs. Use three of them for a Tbolt.

It is really easy to use the transformer from an old microwave oven to make
your own power transformer - the HV and the 110 volt windings are on
separate parts of the core so it is a matter of a few minutes to hacksaw off
the HV winding and you can use standard household THHN wire for your new
secondary - wind ten turns, measure the voltage and use that to figure how
many turns you actually needed.

If someone came out with such a bare board, I would buy 20 of them just to
keep around for projects.

Dave

> -Original Message-
> From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf 
> Of Bob Stewart
> Sent: Wednesday, August 31, 2016 14:29
> To: Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] Anybody want a Thunderbolt power supply?
> 
> OTOH, how many time-nuts have any interest in paying for a 
> power supply that's up to time-nuts standards?  It's really 
> not easy to bring a small product to market at a small price. 
>  Even if you completely discount the personal effort of 
> design, construction, and marketing, there's the issue of 
> packaging.  Without a package, it's just an amateur effort 
> not worth considering.  With a package, such as a Hammond 
> box, the price moves into new territory and nobody's interested.
> 
> Bob 
> 
> 
>   From: Charles Steinmetz 
>  To: time-nuts@febo.com 
>  Sent: Wednesday, August 31, 2016 4:24 PM
>  Subject: Re: [time-nuts] Anybody want a Thunderbolt power supply?
>
> Mark wrote:
> 
> > Some times a full linear supply is not a viable option due 
> to power dissipation/size issues or the utter convenience of 
> using a switching wall wart.
> 
> In the context of the present discussion -- powering a Tbolt for 
> time-nuts use -- the first consideration would just be 
> laughable and the 
> second would be nothing but terminal laziness.
> 
> Best regards,
> 
> Charles
> 
> 
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Re: [time-nuts] Anybody want a Thunderbolt power supply

[Bruce Griffiths]

Just split  the 1uF coupling cap into 2x 2u2 in series in the Cuk dc-dc 
converter add a 1:1 transformer (should be small at 2MHz) between the pair of 
2u2 caps to produce a floating output and use an LT3042 as a post 
regulator.With a mains transformer input supply a separate isolated winding for 
the -12V allows an LT3042 to be used for the negative regulator.
I have a quad LT3042 PCB that I must get around to assembling.One potential 
issue with the LT3042 is the relatively high noise at low frequencies when the 
capacititve bypassing of the resistor that sets the output voltage is 
ineffective.

Bruce
  

On Thursday, 1 September 2016 3:37 PM, Charles Steinmetz 
 wrote:
 

 Bruce wrote:

> Low noise regulators for the +12V and +5V outputs would also be useful.

Very true.  By focusing on the -12v supply, I did not intend to suggest 
that low noise is unimportant on the +12v and +5v supplies.

The suggestion to use LT3042s is a good one, but note that it has an 
output current rating of 200mA.  The Tbolt needs ~250mA at +5v, and 
~700mA at +12v [at startup -- but only ~150mA steady-state, depending on 
ambient temperature].  LT3042s can be used in parallel, so two of them 
for the +5v supply and four of them for the +12v supply would be 
required.  That isn't so bad for the +5v supply, but seems excessive for 
the +12v supply (particularly when three of the four are needed only 
during warmup from cold).

The LT3088 and LT3080 will deliver 800mA and 1.1A, respectively, with 
low noise (but not as low as the LT3042).  One of those might be a 
better choice for the +12v supply.  Similarly, the LT3085 can deliver 
500mA, so one of those could be used for the +5v supply.

Finally: Linear Technology -- Where is our negative-voltage complement 
to the LT3042?

Best regards,

Charles


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Re: [time-nuts] Anybody want a Thunderbolt power supply

[Dave Brown]

Getting the required Thunderbolt supply rails from a nominal 12v dc supply 
of doubtful cleanliness is an issue that also needs to be addressed.  I'm 
still mulling over that one. (and using a triple output switcher from an 
inverter backed mains supply meantime!)
The ex-telco GPSDOs all run on a nominal 24-50 volt DC supply but I don't 
know how they generate their internal supplies. I suspect switchers?

DaveB, NZ

- Original Message - 
From: "Charles Steinmetz" 

To: 
Sent: Thursday, September 01, 2016 3:35 PM
Subject: Re: [time-nuts] Anybody want a Thunderbolt power supply



Bruce wrote:


Low noise regulators for the +12V and +5V outputs would also be useful.


Very true.  By focusing on the -12v supply, I did not intend to suggest 
that low noise is unimportant on the +12v and +5v supplies.


The suggestion to use LT3042s is a good one, but note that it has an 
output current rating of 200mA.  The Tbolt needs ~250mA at +5v, and ~700mA 
at +12v [at startup -- but only ~150mA steady-state, depending on ambient 
temperature].  LT3042s can be used in parallel, so two of them for the +5v 
supply and four of them for the +12v supply would be required.  That isn't 
so bad for the +5v supply, but seems excessive for the +12v supply 
(particularly when three of the four are needed only during warmup from 
cold).


The LT3088 and LT3080 will deliver 800mA and 1.1A, respectively, with low 
noise (but not as low as the LT3042).  One of those might be a better 
choice for the +12v supply.  Similarly, the LT3085 can deliver 500mA, so 
one of those could be used for the +5v supply.


Finally: Linear Technology -- Where is our negative-voltage complement to 
the LT3042?


Best regards,

Charles


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[time-nuts] Sunrise, solar noon, sunset and the Equation of Time

[Mark Sims]

Actually the main factor of determining observed sunset/sunrise times vs 
calculated ones are temperature gradients of the local atmosphere rather than 
than the absolute temperature/humidity/pressure... sunset being more disturbed 
than sunrise.   Local effects of several minutes have been observed.   And once 
you get near the poles all bets are off.

How you define solar noon is also an issue.  Most people would say it is when 
the sun is highest in the sky,  but it is really when the sun crosses 180 
degrees azimuth (0 degrees in the southern hemisphere).   The two different 
methods can be a couple of minutes apart.

The sun elevation angle changes very slowly near solar noon which makes finding 
the exact peak more error prone than the azimuth angle which changes quite 
rapidly.  Lady Heather uses the elevation angle near the equator (are you 
really in the northern or southern hemisphere?) and near the poles 
(longitude/azimuth gets fuzzy).  Azimuth angle is used everywhere else. 


--

> I would also say that variations in air pressure, humidity and
temperature will alter the atmospheric refraction and therefore the
actual rise and set times by up to approx. 20-30 seconds
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Re: [time-nuts] Sunrise, solar noon, sunset and the Equation of Time

[Tim Lister]

On Tue, Aug 30, 2016 at 10:07 PM, Mark Sims  wrote:
> I recently added code to Lady Heather to precisely calculate the sun 
> position, sunrise/solar noon/sunset times and the Equation of Time... Egad, 
> what a deep, dark rabbit hole that leads one down.   And woe be unto thee 
> that trusts any of the online calculators.  Results can be over 10 minutes 
> off and nobody gives times down to the second.  Oh, and there's a half dozen 
> different types of sunrise/sunset to consider.
>
> The gold standard for those calculation is NREL's Solar Position Algorithm.  
> It's awesome.  It's also awesomely complex.  Like 1300 lines of code and 
> several thousand double precision operations and 300+ trig functions per 
> result.   It also has a rather wonky license agreement. (and if your time 
> zone is not Greenwich is can report the sunrise or sunset time for the 
> previous/next day)
>
> I finally settled on Grena's Algorithm 5 for sun position.  It only around 
> 100 lines long uses less than 20 trig function calls to calculate the sun 
> position and produces results comparable to SPA for the years 2010 .. 2110.
>
> Getting sunrise/sunset/solar noon from solar position is a bit more 
> complicated.  I do binary searches and interpolations to find when the sun 
> crosses the magic thresholds to within a second...  it takes about 300 lines 
> of code and 60 sun position evaluations.  Lady Heather can now play sound 
> files at sunrise, solar noon, sunset... your basic GPS disciplined rooster 
> and church bells.
>
> And, for the sundial crowd,  tomorrow is the day the Equation of Time crosses 
> 0.0 seconds so get out and set your sundials...
>
>
Funnily enough I spent yesterday and today wrestling with the same
sort of code. I would recommend JPL HORIZONS for double-checking of
results - I would trust it with my spaceprobe's (if I had one) life...
You can set the time span (in UTC or TT) and then set it to output the
apparent azimuth & elevation at 1 second intervals for any body from
anywhere. There are little 'r', 't', 's' markers after the date to
indicate rise, transit and set.

You can use the local hour angle to give an approximate time within a
day for the rise, transit, and set and then use that as base to
interpolate for the horizon crossing. Chapter 13 of Meeus's
Astronomical Algorithms (a good book but like most books, predating
the major upheaval/revolution of the IAU 2000/2006 changes in
reference systems) has more information on this approach. A word of
caution; the suggested interpolation procedure, which was designed for
reading lines from an almanac, for the right ascension and declination
at +/-1 day *does not* work for the Moon which moves too quickly.
Better to have routine that returns RA,Dec for a given TDB time and
use that directly.

(I would also say that variations in air pressure, humidity and
temperature will alter the atmospheric refraction and therefore the
actual rise and set times by up to approx. 20-30 seconds. Unless Lady
Heather is going to interface to weather stations also, it's probably
not worth trying to kill yourself to get better accuracy better than a
minute ;-)

Tim
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[time-nuts] Datatrak navigation system - looking for signal recordings and technical information

[Philip Pemberton]

Hi there,

I'm currently on what some might call a fool's errand: I'm trying to
build a signal generator to simulate the old Securicor Datatrak (later
Datatrak / Siemens / Mix Telematics) LF signal chain.

Bear with me before you laugh ;)

Datatrak was an LF navigation system, originally built by Securicor to
track their armoured vans as they moved around the UK. It was a little
like Decca Navigator but had a few unique attributes -- automatic lane
identification and a data channel for one.

I've figured out most of the signal format, at least enough to have a
fifty-fifty chance of getting the receiver to lock on and decode it.

At this moment in time I'd really like to find someone who has
recordings of the Datatrak signals. These were transmitted between about
130 and 145kHz and have an odd warbling/chirping sound to them. There's
an example on Youtube:
  https://www.youtube.com/watch?v=NbCfYXab0QQ

I've heard rumours that there's still a Datatrak chain operating in
Argentina and parts of Brazil. A recording from this (upper sideband
mode, radio tuned about 500Hz to 1kHz lower than the signal frequency)
would be tremendously useful if the rumours are true!

Otherwise -- any information on the system would be of interest to me.
I'm piecing things together by (slowly!) reverse-engineering the
receiver firmware... this might go a bit faster if I had a pair of
27C010-capable EPROM emulators, but such is life.

Thanks,
-- 
Phil.
li...@philpem.me.uk
http://www.philpem.me.uk/
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Re: [time-nuts] Anybody want a Thunderbolt power supply

[Bob Camp]

HI

Just get a linear supply from somebody you have heard of before and it will do 
fine. 
The key point is to avoid a switcher. There are still lots of linears out 
there. The designs
have not changed much for the last 40 years. They pretty much all do it the 
same way.

Bob

> On Aug 31, 2016, at 9:13 PM, Cube Central  wrote:
> 
> With the talk of Thunderbolt power supplies and their qualities, and after
> seeing the post about the TAPR HPSDR LPU... I am beginning to wonder about
> the power source I have for mine, as the "Temp" field shown on the following
> link has always been funny.  It seems to track and keep the outputs up well
> enough, but I wonder if a better power supply is warranted.  I don't have
> the background to feel confident in creating one that plugs into Mains
> power, even with a kit from TAPR.   I've searched for similar issues (some
> time back) but didn't come up with an answer.  Maybe someone here might know
> what is going on?  Thanks in advance (link follows)
> 
> http://i.imgur.com/ByXhFLS.png
> 
> 
>   -Randal
>   (at CubeCentral)
> 
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Re: [time-nuts] Anybody want a Thunderbolt power supply?

[Jeff AC0C]

I bought a module off ebay for a project recently.  It has a LM317/LM337 
pair, small heat sinks, regulator, bypass caps, rectifiers and filtering 
caps all on one board for about $10 delivered.  To this you add a small 
transformer and piggy-back a 7805T/heat sink and that would give the 3 
voltages required by this unit.


Of course it's linear so it's got the linear heat dissipation issue but by 
the right pick of transformer that could be as low as about 3W (around 2KWH 
per month).  Then again, it's also got the linear noise "problems" which are 
pretty much zero.


73/jeff/ac0c
www.ac0c.com
alpha-charlie-zero-charlie

-Original Message- 
From: Bob kb8tq

Sent: Wednesday, August 31, 2016 7:49 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Anybody want a Thunderbolt power supply?

Hi

It is not that hard to do. Use a linear rather than a switching approach. 
Run the +12 and +5 supplies off of LT1764 regulators. The -12 is very low 
current, run it off of a low noise op amp. There are lots of toroidal line 
transformers that will drive something like this.


Bob


On Aug 31, 2016, at 6:20 PM, Cube Central  wrote:

Wow, given all the responses about the cleanliness of the power into a 
Thunderbolt, I would be even more interested in a power supply that did 
*not* leave the "last mile" up to me.  I would be more interested in a 
"pretty clean" power supply that I could just plug in and go.  Any 
thoughts of me actually wiring the last bit of it make me break out in a 
cold sweat and come face to face with my (established, and sadly 
slow-to-expand) limitations.


Maybe I'm the only one that would be interested in such a solution?  I 
hope not, but I can see that there is a lot to consider about such a 
thing.


Cheers!

   -Randal
   (at CubeCentral)

-Original Message-
From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Bob 
Stewart

Sent: Wednesday, 31 August, 2016 15:29
To: Discussion of precise time and frequency measurement 


Subject: Re: [time-nuts] Anybody want a Thunderbolt power supply?

OTOH, how many time-nuts have any interest in paying for a power supply 
that's up to time-nuts standards?  It's really not easy to bring a small 
product to market at a small price.  Even if you completely discount the 
personal effort of design, construction, and marketing, there's the issue 
of packaging.  Without a package, it's just an amateur effort not worth 
considering.  With a package, such as a Hammond box, the price moves into 
new territory and nobody's interested.


Bob


 From: Charles Steinmetz 
To: time-nuts@febo.com
Sent: Wednesday, August 31, 2016 4:24 PM
Subject: Re: [time-nuts] Anybody want a Thunderbolt power supply?

Mark wrote:

Some times a full linear supply is not a viable option due to power 
dissipation/size issues or the utter convenience of using a switching 
wall wart.


In the context of the present discussion -- powering a Tbolt for time-nuts 
use -- the first consideration would just be laughable and the second 
would be nothing but terminal laziness.


Best regards,

Charles


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Re: [time-nuts] Anybody want a Thunderbolt power supply

[Cube Central]

With the talk of Thunderbolt power supplies and their qualities, and after
seeing the post about the TAPR HPSDR LPU... I am beginning to wonder about
the power source I have for mine, as the "Temp" field shown on the following
link has always been funny.  It seems to track and keep the outputs up well
enough, but I wonder if a better power supply is warranted.  I don't have
the background to feel confident in creating one that plugs into Mains
power, even with a kit from TAPR.   I've searched for similar issues (some
time back) but didn't come up with an answer.  Maybe someone here might know
what is going on?  Thanks in advance (link follows)

http://i.imgur.com/ByXhFLS.png


-Randal
(at CubeCentral)

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Re: [time-nuts] Anybody want a Thunderbolt power supply?

[Charles Steinmetz]

Bob wrote:


I don't mean to cause offense, but is everything you don't like crap?  The 
reality is that whatever the market will bear is what determines what comes to 
market.  If you can find high quality goods on ebay that can be modified to fit 
your needs, then you win.  There is a substantial market that either cannot do 
those mods or would rather spend their time elsewhere.  So, what they're 
willing to pay is going to determine what's available for sale.


No, but I often view things that don't do the job they need to do as 
crap, especially if they are offered in such a way as to suggest that 
they are, in fact, useful for the intended purpose.  So, let's take the 
proposed power supply -- a switching regulator to develop +5v and -12v 
supplies from an existing +12v supply, with noise of 35mVp-p, offered 
specifically as a power supply solution for Tbolt GPSDOs.  If the 
offering said explicitly that a Tbolt can't provide its best performance 
with the product because of its high noise level, then I might be on the 
fence about whether it was "crap."  But if it were offered as a power 
supply for Tbolts with no mention of what I consider to be a large 
departure from acceptable performance for the intended use, then yes, 
I'd probably consider it "crap."


The issue is that many users do not know what the relevant needs are. 
Rightly or wrongly, they are relying on suppliers to do that job for 
them.  So, offering something for a particular use carries the 
implication that it is really useful for that purpose.  If a seller 
tells a time-nut that a power supply is designed to run a Tbolt, an 
implicit representation has been made that it will work in that role as 
a time-nut would expect it to.  But IMO, the proposed product would not 
do so because of the high noise level.


So, what distinguishes this from packages that have been sold to 
time-nuts in the past that included power supplies that also did not 
work in that role as a time-nut would expect?  In those cases, due 
largely to this list, there was widespread discussion of the issue and 
equally widespread knowledge that for time-nuts-quality results, the PS 
that came with the package needed to be replaced with something better. 
 So at this point, if someone offers a PS to time nuts for use with 
Tbolts, it would be natural to assume that the seller was familiar with 
that history and was offering the "something better."  So today, if that 
is *not* the case, it should be stated explicitly.


Best regards,

Charles


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Re: [time-nuts] Anybody want a Thunderbolt power supply?

[Bob kb8tq]

Hi

It is not that hard to do. Use a linear rather than a switching approach. Run 
the +12 and +5 supplies off of LT1764 regulators. The -12 is very low current, 
run it off of a low noise op amp. There are lots of toroidal line transformers 
that will drive something like this. 

Bob

> On Aug 31, 2016, at 6:20 PM, Cube Central  wrote:
> 
> Wow, given all the responses about the cleanliness of the power into a 
> Thunderbolt, I would be even more interested in a power supply that did *not* 
> leave the "last mile" up to me.  I would be more interested in a "pretty 
> clean" power supply that I could just plug in and go.  Any thoughts of me 
> actually wiring the last bit of it make me break out in a cold sweat and come 
> face to face with my (established, and sadly slow-to-expand) limitations.
> 
> Maybe I'm the only one that would be interested in such a solution?  I hope 
> not, but I can see that there is a lot to consider about such a thing.
> 
> Cheers!
> 
>-Randal 
>(at CubeCentral)
> 
> -Original Message-
> From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Bob Stewart
> Sent: Wednesday, 31 August, 2016 15:29
> To: Discussion of precise time and frequency measurement 
> Subject: Re: [time-nuts] Anybody want a Thunderbolt power supply?
> 
> OTOH, how many time-nuts have any interest in paying for a power supply 
> that's up to time-nuts standards?  It's really not easy to bring a small 
> product to market at a small price.  Even if you completely discount the 
> personal effort of design, construction, and marketing, there's the issue of 
> packaging.  Without a package, it's just an amateur effort not worth 
> considering.  With a package, such as a Hammond box, the price moves into new 
> territory and nobody's interested.
> 
> Bob 
> 
> 
>  From: Charles Steinmetz 
> To: time-nuts@febo.com
> Sent: Wednesday, August 31, 2016 4:24 PM
> Subject: Re: [time-nuts] Anybody want a Thunderbolt power supply?
> 
> Mark wrote:
> 
>> Some times a full linear supply is not a viable option due to power 
>> dissipation/size issues or the utter convenience of using a switching wall 
>> wart.
> 
> In the context of the present discussion -- powering a Tbolt for time-nuts 
> use -- the first consideration would just be laughable and the second would 
> be nothing but terminal laziness.
> 
> Best regards,
> 
> Charles
> 
> 
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Re: [time-nuts] Anybody want a Thunderbolt power supply

[Bruce Griffiths]

If onen is going to use a dc-dc converter the Cuk converter used here is a nice 
topology in that it can have low input and output ripple currents. However 
input and output filters like the Murata BNX002/BNX005 series would have been 
useful as would an LM3042 linear post regulator for the -12V output.. Low noise 
regulators for the +12V and +5V outputs would also be useful.
Bruce
 

On Thursday, 1 September 2016 11:48 AM, Mike Naruta AA8K  
wrote:
 

 
I use the TAPR HPSDR LPU:

< https://www.tapr.org/kits_lpu.html >


I run two Trimble Thunderbolts on a LPU that uses the house 13.6 
Volt supply that is backed up with two 6 Volt golf cart 
batteries in series.  I didn't bother installing the Anderson 
Power Pole and ATX connectors, but wired directly to the circuit 
board.


Mike - AA8K

On 08/30/2016 10:23 PM, Nick Sayer via time-nuts wrote:
> A little board to generate -12 and +5 from a 15 watt 12 VDC input wouldn’t be 
> too hard to design. If I put one out for $25, would anyone like one?
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Re: [time-nuts] Anybody want a Thunderbolt power supply?

[Charles Steinmetz]

Bob wrote:


OTOH, how many time-nuts have any interest in paying for a power supply that's 
up to time-nuts standards?  It's really not easy to bring a small product to 
market at a small price.  Even if you completely discount the personal effort 
of design, construction, and marketing, there's the issue of packaging.  
Without a package, it's just an amateur effort not worth considering.  With a 
package, such as a Hammond box, the price moves into new territory and nobody's 
interested.


So the answer is to bring crap to market because nobody will pay for 
something that actually does the job?


IMO, the answer is to accept that the small, "little gizmo" providers 
simply cannot fulfill this need efficiently.  I provided one solution, 
using a surplus device from a large supplier and fifteen minutes of 
soldering-iron time.  Even if you buy a box for it, it won't cost much 
more than the $25 the OP proposed (and maybe not as much -- the ones 
I've made have cost less than $25 each).  (And note that the OP did not 
propose a complete, mains-to-Tbolt solution.  The proposed solution 
assumed an existing mains-to-12v supply.)


That is part (the essential part, IMO) of the "little gizmo" provider's 
business model -- find niche markets where things made at that scale 
provide *better* performance than the alternatives.  There are lots of 
areas where this can be done, but also very many more where it cannot. 
The "little gizmo" provider is well-advised to learn how to tell the one 
from the other.


Best regards,

Charles


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Re: [time-nuts] Anybody want a Thunderbolt power supply

[Mike Naruta AA8K]

I use the TAPR HPSDR LPU:

< https://www.tapr.org/kits_lpu.html >


I run two Trimble Thunderbolts on a LPU that uses the house 13.6 
Volt supply that is backed up with two 6 Volt golf cart 
batteries in series.  I didn't bother installing the Anderson 
Power Pole and ATX connectors, but wired directly to the circuit 
board.



Mike - AA8K

On 08/30/2016 10:23 PM, Nick Sayer via time-nuts wrote:

A little board to generate -12 and +5 from a 15 watt 12 VDC input wouldn’t be 
too hard to design. If I put one out for $25, would anyone like one?
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Re: [time-nuts] Anybody want a Thunderbolt power supply?

[Charles Steinmetz]

Chris wrote:


Did you try any passive filters between the switchers and linear regulators?


Yes, I *always* use passive filters on the outputs of switching 
regulators.  As others have posted, it's not just a matter of the 
conducted noise on the supply rail -- switching noise propogates on the 
ground bus, and it is also radiated and coupled into downstream stages, 
including downstream power supply buses.  That is, it can very easily 
bypass whatever filtering you put in the direct conduction path.


Best regards.

Charles


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Re: [time-nuts] Anybody want a Thunderbolt power supply?

[Nick Sayer via time-nuts]

When I began the design process, I assumed - as would be reasonable - that ~30 
mV P-P of noise and ripple were acceptable for input power supplies, and that 
before they were used for a precision purpose within the device that there 
would be further filtering if for no other reason that you’d think they’d want 
to limit coupled interference on the power lines. My assumption, given the 
extremely low draw on the -12 line was that they were using the -12 line just 
for the RS-232 level shifter (and that they were too lazy to use a MAX232 like 
everybody else).

Now that I’ve posted and had my assumptions disabused, I’ll need to go back to 
the drawing board for another attempt. The price point won’t likely be $25 
anymore, but the question was whether anyone wanted a Tbolt power supply, and 
if I offer anything at all, I intend for it to be reasonably useful for its 
intended purpose. Like all the things I make for sale, it will be open 
hardware, which will afford everyone here more than enough opportunity for 
Monday morning quarterbacking. :)


> On Aug 31, 2016, at 4:02 PM, Charles Steinmetz  wrote:
> 
> Bob wrote:
> 
>> I don't mean to cause offense, but is everything you don't like crap?  The 
>> reality is that whatever the market will bear is what determines what comes 
>> to market.  If you can find high quality goods on ebay that can be modified 
>> to fit your needs, then you win.  There is a substantial market that either 
>> cannot do those mods or would rather spend their time elsewhere.  So, what 
>> they're willing to pay is going to determine what's available for sale.
> 
> No, but I often view things that don't do the job they need to do as crap, 
> especially if they are offered in such a way as to suggest that they are, in 
> fact, useful for the intended purpose.  So, let's take the proposed power 
> supply -- a switching regulator to develop +5v and -12v supplies from an 
> existing +12v supply, with noise of 35mVp-p, offered specifically as a power 
> supply solution for Tbolt GPSDOs.  If the offering said explicitly that a 
> Tbolt can't provide its best performance with the product because of its high 
> noise level, then I might be on the fence about whether it was "crap."  But 
> if it were offered as a power supply for Tbolts with no mention of what I 
> consider to be a large departure from acceptable performance for the intended 
> use, then yes, I'd probably consider it "crap."
> 
> The issue is that many users do not know what the relevant needs are. Rightly 
> or wrongly, they are relying on suppliers to do that job for them.  So, 
> offering something for a particular use carries the implication that it is 
> really useful for that purpose.  If a seller tells a time-nut that a power 
> supply is designed to run a Tbolt, an implicit representation has been made 
> that it will work in that role as a time-nut would expect it to.  But IMO, 
> the proposed product would not do so because of the high noise level.
> 
> So, what distinguishes this from packages that have been sold to time-nuts in 
> the past that included power supplies that also did not work in that role as 
> a time-nut would expect?  In those cases, due largely to this list, there was 
> widespread discussion of the issue and equally widespread knowledge that for 
> time-nuts-quality results, the PS that came with the package needed to be 
> replaced with something better.  So at this point, if someone offers a PS to 
> time nuts for use with Tbolts, it would be natural to assume that the seller 
> was familiar with that history and was offering the "something better."  So 
> today, if that is *not* the case, it should be stated explicitly.
> 
> Best regards,
> 
> Charles
> 
> 
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Re: [time-nuts] Anybody want a Thunderbolt power supply?

[Charles Steinmetz]

Mark wrote:


Some times a full linear supply is not a viable option due to power 
dissipation/size issues or the utter convenience of using a switching wall wart.


In the context of the present discussion -- powering a Tbolt for 
time-nuts use -- the first consideration would just be laughable and the 
second would be nothing but terminal laziness.


Best regards,

Charles


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Re: [time-nuts] Anybody want a Thunderbolt power supply?

[Charles Steinmetz]

jim wrote:


with the venerable 2n3055 (1960s!) as the series pass device, and an
exotic TIP29 (my 1985 databook has it, but the original datasheet says
1968) to drive it..

They probably used the 1970s versions of the transistor, of course,
since the 723 didn't come out til early 70s..


Fairchild introduced the orginal 723 (the µA723) in 1968.  I think 
National brought out the LM723 within the year, but can't swear to it.


While the schematic I posted shows a TIP29 driver transistor, that was 
for a different, 3A supply.  The lower-current +/-12v supplies in the 
HTAA-16W-A do without the driver, and connect the 3055 directly to the 
723 output (which can source up to 150mA).  The schematic I posted also 
shows foldback current limiting, which the +/-12v supplies in the 
HTAA-16W-A do not have.


Best regards,

Charles


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Re: [time-nuts] Anybody want a Thunderbolt power supply?

[Bob kb8tq]

Hi

The fact is that commercial linear supplies are still out there for pretty 
cheap prices. The price of a usable switcher is a very small fraction of the 
price of a Tbolt. Noise on the switcher is a big deal. Not everybody seems to 
care about low phase noise on the 10 MHz. Switcher frequency supply noise has 
very little impact on the PPS output. 

Bob

> On Aug 31, 2016, at 5:29 PM, Bob Stewart  wrote:
> 
> OTOH, how many time-nuts have any interest in paying for a power supply 
> that's up to time-nuts standards?  It's really not easy to bring a small 
> product to market at a small price.  Even if you completely discount the 
> personal effort of design, construction, and marketing, there's the issue of 
> packaging.  Without a package, it's just an amateur effort not worth 
> considering.  With a package, such as a Hammond box, the price moves into new 
> territory and nobody's interested.
> 
> Bob 
> 
> 
>  From: Charles Steinmetz 
> To: time-nuts@febo.com 
> Sent: Wednesday, August 31, 2016 4:24 PM
> Subject: Re: [time-nuts] Anybody want a Thunderbolt power supply?
> 
> Mark wrote:
> 
>> Some times a full linear supply is not a viable option due to power 
>> dissipation/size issues or the utter convenience of using a switching wall 
>> wart.
> 
> In the context of the present discussion -- powering a Tbolt for 
> time-nuts use -- the first consideration would just be laughable and the 
> second would be nothing but terminal laziness.
> 
> Best regards,
> 
> Charles
> 
> 
> ___
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> 
> 
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Re: [time-nuts] Anybody want a Thunderbolt power supply?

[Alexander Pummer]

there are peoples and societies for whom the most important parameter is 
the price of the goods, and there are also some societies for them the 
most important is the proffit


73

Alex


On 8/31/2016 3:13 PM, Bob Stewart wrote:

Charles,
said: "So the answer is to bring crap to market because nobody will pay for 
something that actually does the job?"
I don't mean to cause offense, but is everything you don't like crap?  The 
reality is that whatever the market will bear is what determines what comes to 
market.  If you can find high quality goods on ebay that can be modified to fit 
your needs, then you win.  There is a substantial market that either cannot do 
those mods or would rather spend their time elsewhere.  So, what they're 
willing to pay is going to determine what's available for sale.

As an example, my cost for the Hammond box I use with my GPSDO, with finished 
end panels, is just under $60.  From that viewpoint, I shouldn't bother to make 
it, because a surplus unit can always be found for a cheaper price, as long as 
I'm willing to accept whatever unknown baggage (no schematics, unobtainium 
parts, no software, etc) comes with that surplus unit.
Bob
  -
AE6RV.com

GFS GPSDO list:
groups.yahoo.com/neo/groups/GFS-GPSDOs/info

   From: Charles Steinmetz 
  To: time-nuts@febo.com
  Sent: Wednesday, August 31, 2016 5:02 PM
  Subject: Re: [time-nuts] Anybody want a Thunderbolt power supply?

Bob wrote:



OTOH, how many time-nuts have any interest in paying for a power supply that's 
up to time-nuts standards?  It's really not easy to bring a small product to 
market at a small price.  Even if you completely discount the personal effort 
of design, construction, and marketing, there's the issue of packaging.  
Without a package, it's just an amateur effort not worth considering.  With a 
package, such as a Hammond box, the price moves into new territory and nobody's 
interested.

So the answer is to bring crap to market because nobody will pay for
something that actually does the job?

IMO, the answer is to accept that the small, "little gizmo" providers
simply cannot fulfill this need efficiently.  I provided one solution,
using a surplus device from a large supplier and fifteen minutes of
soldering-iron time.  Even if you buy a box for it, it won't cost much
more than the $25 the OP proposed (and maybe not as much -- the ones
I've made have cost less than $25 each).  (And note that the OP did not
propose a complete, mains-to-Tbolt solution.  The proposed solution
assumed an existing mains-to-12v supply.)

That is part (the essential part, IMO) of the "little gizmo" provider's
business model -- find niche markets where things made at that scale
provide *better* performance than the alternatives.  There are lots of
areas where this can be done, but also very many more where it cannot.
The "little gizmo" provider is well-advised to learn how to tell the one
from the other.

Best regards,

Charles


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-
No virus found in this message.
Checked by AVG - www.avg.com
Version: 2016.0.7752 / Virus Database: 4649/12916 - Release Date: 08/31/16


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Re: [time-nuts] Anybody want a Thunderbolt power supply?

[Cube Central]

Wow, given all the responses about the cleanliness of the power into a 
Thunderbolt, I would be even more interested in a power supply that did *not* 
leave the "last mile" up to me.  I would be more interested in a "pretty clean" 
power supply that I could just plug in and go.  Any thoughts of me actually 
wiring the last bit of it make me break out in a cold sweat and come face to 
face with my (established, and sadly slow-to-expand) limitations.

Maybe I'm the only one that would be interested in such a solution?  I hope 
not, but I can see that there is a lot to consider about such a thing.

Cheers!

-Randal 
(at CubeCentral)

-Original Message-
From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Bob Stewart
Sent: Wednesday, 31 August, 2016 15:29
To: Discussion of precise time and frequency measurement 
Subject: Re: [time-nuts] Anybody want a Thunderbolt power supply?

OTOH, how many time-nuts have any interest in paying for a power supply that's 
up to time-nuts standards?  It's really not easy to bring a small product to 
market at a small price.  Even if you completely discount the personal effort 
of design, construction, and marketing, there's the issue of packaging.  
Without a package, it's just an amateur effort not worth considering.  With a 
package, such as a Hammond box, the price moves into new territory and nobody's 
interested.

Bob 


  From: Charles Steinmetz 
 To: time-nuts@febo.com
 Sent: Wednesday, August 31, 2016 4:24 PM
 Subject: Re: [time-nuts] Anybody want a Thunderbolt power supply?
   
Mark wrote:

> Some times a full linear supply is not a viable option due to power 
> dissipation/size issues or the utter convenience of using a switching wall 
> wart.

In the context of the present discussion -- powering a Tbolt for time-nuts use 
-- the first consideration would just be laughable and the second would be 
nothing but terminal laziness.

Best regards,

Charles


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Re: [time-nuts] Anybody want a Thunderbolt power supply?

[Bob Stewart]

Charles,
said: "So the answer is to bring crap to market because nobody will pay for 
something that actually does the job?"
I don't mean to cause offense, but is everything you don't like crap?  The 
reality is that whatever the market will bear is what determines what comes to 
market.  If you can find high quality goods on ebay that can be modified to fit 
your needs, then you win.  There is a substantial market that either cannot do 
those mods or would rather spend their time elsewhere.  So, what they're 
willing to pay is going to determine what's available for sale.

As an example, my cost for the Hammond box I use with my GPSDO, with finished 
end panels, is just under $60.  From that viewpoint, I shouldn't bother to make 
it, because a surplus unit can always be found for a cheaper price, as long as 
I'm willing to accept whatever unknown baggage (no schematics, unobtainium 
parts, no software, etc) comes with that surplus unit.
Bob
 -
AE6RV.com

GFS GPSDO list:
groups.yahoo.com/neo/groups/GFS-GPSDOs/info

  From: Charles Steinmetz 
 To: time-nuts@febo.com 
 Sent: Wednesday, August 31, 2016 5:02 PM
 Subject: Re: [time-nuts] Anybody want a Thunderbolt power supply?
   
Bob wrote:

> OTOH, how many time-nuts have any interest in paying for a power supply 
> that's up to time-nuts standards?  It's really not easy to bring a small 
> product to market at a small price.  Even if you completely discount the 
> personal effort of design, construction, and marketing, there's the issue of 
> packaging.  Without a package, it's just an amateur effort not worth 
> considering.  With a package, such as a Hammond box, the price moves into new 
> territory and nobody's interested.

So the answer is to bring crap to market because nobody will pay for 
something that actually does the job?

IMO, the answer is to accept that the small, "little gizmo" providers 
simply cannot fulfill this need efficiently.  I provided one solution, 
using a surplus device from a large supplier and fifteen minutes of 
soldering-iron time.  Even if you buy a box for it, it won't cost much 
more than the $25 the OP proposed (and maybe not as much -- the ones 
I've made have cost less than $25 each).  (And note that the OP did not 
propose a complete, mains-to-Tbolt solution.  The proposed solution 
assumed an existing mains-to-12v supply.)

That is part (the essential part, IMO) of the "little gizmo" provider's 
business model -- find niche markets where things made at that scale 
provide *better* performance than the alternatives.  There are lots of 
areas where this can be done, but also very many more where it cannot. 
The "little gizmo" provider is well-advised to learn how to tell the one 
from the other.

Best regards,

Charles


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Re: [time-nuts] Anybody want a Thunderbolt power supply?

[Bob Stewart]

OTOH, how many time-nuts have any interest in paying for a power supply that's 
up to time-nuts standards?  It's really not easy to bring a small product to 
market at a small price.  Even if you completely discount the personal effort 
of design, construction, and marketing, there's the issue of packaging.  
Without a package, it's just an amateur effort not worth considering.  With a 
package, such as a Hammond box, the price moves into new territory and nobody's 
interested.

Bob 


  From: Charles Steinmetz 
 To: time-nuts@febo.com 
 Sent: Wednesday, August 31, 2016 4:24 PM
 Subject: Re: [time-nuts] Anybody want a Thunderbolt power supply?
   
Mark wrote:

> Some times a full linear supply is not a viable option due to power 
> dissipation/size issues or the utter convenience of using a switching wall 
> wart.

In the context of the present discussion -- powering a Tbolt for 
time-nuts use -- the first consideration would just be laughable and the 
second would be nothing but terminal laziness.

Best regards,

Charles


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Re: [time-nuts] Anybody want a Thunderbolt power supply?

[Charles Steinmetz]

Mark wrote:


You have to be careful choosing a linear regulator to clean up a switching 
supply.   Many just wind up passing the noise through.  Pay attention to the 
noise, PSRR and CMRR vs frequency specs, etc


Precisely the reason to avoid switchers entirely and use linear-only 
voltage regulators to power noise-sensitive circuits.  As I mentioned 
before, I had to use two stages of well-designed linear regulation to 
make any switching supply acceptable (at a time-nuts level) for use with 
a Tbolt.


Best regards,

Charles


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Re: [time-nuts] Anybody want a Thunderbolt power supply?

[Chris Caudle]

On Wed, August 31, 2016 2:16 pm, Charles Steinmetz wrote:
> I had to use two stages of well-designed linear regulation to
> make any switching supply acceptable (at a time-nuts level) for use with
> a Tbolt.

Did you try any passive filters between the switchers and linear regulators?

-- 
Chris Caudle


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Re: [time-nuts] Anybody want a Thunderbolt power supply?

[jimlux]

On 8/31/16 1:52 PM, Adrian Godwin wrote:

I'm being Devil's Advocate here because I certainly realise switchers do
generate high frequency noise. But wasn't the intention of them to make
filtering easier, with smaller filter components, exactly because they
operate at higher frequencies ?

So why do they fail ? Is it cost-cutting to make them only just good enough
for typical uses ? Shouldn't it be possible to make the best possible
supply from a switcher, if only cost and weight weren't the first
considerations ?



Sure.. you can do a bunch of LC low pass sections and knock it down, but 
building a *wideband* low pass filter with good ultimate rejection is 
also challenging.


In a system I'm actually sitting next to, we have a switcher followed by 
a 60dB rejection lumped LC followed by the power distribution, followed 
by a 60 dB rejection lumped LC followed by a linear regulator.


When you're at this kind of level, layout and mechanical arrangement is 
important, because the switching noise (which is also on the input) can 
couple "around" your other circuits.


The other challenge is that those filters have resistive loss - if you 
want good regulation, how do you get your "sense" voltage back to the 
regulator without that path being the path for the noise - so you'd need 
to put LP filters on the sense line.


And of course, the L's need to be shielded.
And you put it in nesting boxes made of steel

A linear regulator is a LOT easier.

If you aren't power dissipation constrained, then it's often the easiest 
way to get to where you want to be.

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Re: [time-nuts] Anybody want a Thunderbolt power supply?

[Adrian Godwin]

I'm being Devil's Advocate here because I certainly realise switchers do
generate high frequency noise. But wasn't the intention of them to make
filtering easier, with smaller filter components, exactly because they
operate at higher frequencies ?

So why do they fail ? Is it cost-cutting to make them only just good enough
for typical uses ? Shouldn't it be possible to make the best possible
supply from a switcher, if only cost and weight weren't the first
considerations ?


On Wed, Aug 31, 2016 at 9:45 PM, Mark Sims  wrote:

> Yes,  at times I used a two stage linear regulator.  The first stage had
> excellent low freq rejection and the final stage too care of the high freq
> stuff.
>
> Some times a full linear supply is not a viable option due to power
> dissipation/size issues or the utter convenience of using a switching wall
> wart.
>
> 
>
> > Precisely the reason to avoid switchers entirely and use linear-only
> voltage regulators to power noise-sensitive circuits.  As I mentioned
> before, I had to use two stages of well-designed linear regulation to
> make any switching supply acceptable (at a time-nuts level) for use with
> a Tbolt.
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[time-nuts] Anybody want a Thunderbolt power supply?

[Mark Sims]

Yes,  at times I used a two stage linear regulator.  The first stage had 
excellent low freq rejection and the final stage too care of the high freq 
stuff.

Some times a full linear supply is not a viable option due to power 
dissipation/size issues or the utter convenience of using a switching wall wart.



> Precisely the reason to avoid switchers entirely and use linear-only 
voltage regulators to power noise-sensitive circuits.  As I mentioned 
before, I had to use two stages of well-designed linear regulation to 
make any switching supply acceptable (at a time-nuts level) for use with 
a Tbolt.
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Re: [time-nuts] Anybody want a Thunderbolt power supply?

[Edesio Costa e Silva]

Have a look at Linear Application Note 101 by Jim Williams: Minimizing
Switching Regulator Residue in Linear Regulator Outputs


Edésio

On Wed, Aug 31, 2016 at 07:01:44PM +, Mark Sims wrote:
> You have to be careful choosing a linear regulator to clean up a switching 
> supply.   Many just wind up passing the noise through.  Pay attention to the 
> noise, PSRR and CMRR vs frequency specs, etc
> 
> Take a look at the "voltage regulation" section of that home built VNA page 
> for an example:
> http://hforsten.com/cheap-homemade-30-mhz-6-ghz-vector-network-analyzer.html
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Re: [time-nuts] Anybody want a Thunderbolt power supply?

[Charles Steinmetz]

Jerry wrote:


Charles, do you have the schematic for the HTAA-16W-A  ?  The KO4BB mod has 
limited info


Clint wrote:

>> Ah,  these are the LM723 based linear supplies,  Lambda Coutant made
>> variants as did Farnell,  they're renowned as high reliability,  low 
noise

>> supplies.
>>
>> There are schematics out there for the variants but they're all 
extremely

>> similar if not identical.

I don't have a schematic for the HTAA-16W-A, but Clint is correct -- 
each of the three supplies is a bog-standard LM723 circuit.  I am 
attaching a reverse-engineered schematic I found on the net of a 
different Power One supply as an example.  I hope I've made it small 
enough to get through the server without list-minder approval, in case 
Tom is still away.


Best regards,

Charles


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Re: [time-nuts] Anybody want a Thunderbolt power supply?

[jimlux]

On 8/31/16 12:01 PM, Mark Sims wrote:

You have to be careful choosing a linear regulator to clean up a switching 
supply.   Many just wind up passing the noise through.  Pay attention to the 
noise, PSRR and CMRR vs frequency specs, etc



Indeed..
a lot of monolithic regulators have a remarkably low cutoff frequency.

On the other hand, the LT3042 has 80 dB PSRR up to a few MHz.  55dB at 
10 MHz.







Take a look at the "voltage regulation" section of that home built VNA page for 
an example:
http://hforsten.com/cheap-homemade-30-mhz-6-ghz-vector-network-analyzer.html
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Re: [time-nuts] Anybody want a Thunderbolt power supply?

[jimlux]

On 8/31/16 11:22 AM, Charles Steinmetz wrote:

Jerry wrote:


Charles, do you have the schematic for the HTAA-16W-A  ?  The KO4BB
mod has limited info


Clint wrote:


Ah,  these are the LM723 based linear supplies,  Lambda Coutant made
variants as did Farnell,  they're renowned as high reliability,  low

noise

supplies.

There are schematics out there for the variants but they're all

extremely

similar if not identical.


I don't have a schematic for the HTAA-16W-A, but Clint is correct --
each of the three supplies is a bog-standard LM723 circuit.


with the venerable 2n3055 (1960s!) as the series pass device, and an 
exotic TIP29 (my 1985 databook has it, but the original datasheet says 
1968) to drive it..


They probably used the 1970s versions of the transistor, of course, 
since the 723 didn't come out til early 70s..


Some things just keep working...
I think they've amply recovered the development cost for those parts..


 I am

attaching a reverse-engineered schematic I found on the net of a
different Power One supply as an example.  I hope I've made it small
enough to get through the server without list-minder approval, in case
Tom is still away.

Best regards,

Charles




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[time-nuts] Anybody want a Thunderbolt power supply?

[Mark Sims]

You have to be careful choosing a linear regulator to clean up a switching 
supply.   Many just wind up passing the noise through.  Pay attention to the 
noise, PSRR and CMRR vs frequency specs, etc

Take a look at the "voltage regulation" section of that home built VNA page for 
an example:
http://hforsten.com/cheap-homemade-30-mhz-6-ghz-vector-network-analyzer.html
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[time-nuts] You will be aware of the three different definitions of sunset, of course.

[Mark Sims]

>  You will be aware of the three different definitions of sunset, of course.

Actually 5...  Physical, Official, Civil, Natutical, and Astronomical.Plus 
Lady Heather lets you specify an arbitrary horizon angle.  

>  It calculates positions for the moon as well.

Lady Heather also does the moon.  Calculates the moon position, illumination 
percentage, and draws the moon on the analog watch display.   The sun is shown  
on the watch display and the satellite position map.  Internally, the sun is 
treated as a satellite (with PRN number 256).

People have been using Lady Heather's sun info for doing things like disabling 
satellite tracking of satellites near the sun.   The moon info has been used 
for things like moon bounce communications and ranging experiments.

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Re: [time-nuts] Anybody want a Thunderbolt power supply?

[Clint Jay]

Ah,  these are the LM723 based linear supplies,  Lambda Coutant made
variants as did Farnell,  they're renowned as high reliability,  low noise
supplies.

There are schematics out there for the variants but they're all extremely
similar if not identical.

I think I may even have a couple of original manuals with schematics,  I
may be able to dig them out and scan if they're of interest.

On 31 Aug 2016 13:01, "Jerry O. Stern"  wrote:

> Charles, do you have the schematic for the HTAA-16W-A  ?  The KO4BB mod
> has limited info
>
> Tnx
>
> Jerry
> k1...@arrl.net
>
>
> -Original Message-
> From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Charles
> Steinmetz
> Sent: Wednesday, August 31, 2016 4:49 AM
> To: time-nuts@febo.com
> Subject: Re: [time-nuts] Anybody want a Thunderbolt power supply?
>
> Nick wrote:>
>
> > I’m going to shoot for <= 35 mV P-P. If you need better than that,
> > then it probably turns into a hybrid switching+linear system
>
> It's been years since I played with Tbolts (as opposed to just using
> them), but as I recall there was no possibility whatever of getting the
> best results from any switching supply without at least one stage of linear
> "polishing."  In fact, everything I tried with initial switching regulation
> benefitted from two levels of linear polishing.  It was my conclusion that
> starting with a switching supply of any sort is a bad idea.
>
> I found that for best performance the -12v supply, which feeds the DAC,
> needs to be about 1000 times better than what you are shooting for (i.e.,
> low tens of uVp-p).  That surprised me, because I assumed there must be
> some internal regulation of the DAC supplies -- but it was what my testing
> showed.
>
> Sure, a Tbolt will work with dirtier power than that, but for real
> time-nuts performance I consider an all-linear supply with an
> ultra-low-noise -12v rail to be absolutely necessary.  Since that is not
> very hard to provide, I see no reason to try to make do with less.
>
> One low-cost solution is to wait for a cheap Power One HTAA-16W-A
> triple-output power supply to show up on ebay, and do a very minor
> modification to raise the +12v current limit (so it will handle the first
> moments of a cold start without current limiting) as detailed here:
>
>  Equipment/Power_One/Power_One_HTAA-16W-A_mod_for_
> Thunderbolt_power_supply.pdf>
>
> That approach achieves excellent results -- close to the best you can do
> -- with very little fiddling.  If one wants the very best performance, the
> -12v supply can be adjusted down to -16v or so to provide the headroom to
> add a ULN regulator or a capacitance multiplier.  (The Tbolt only draws a
> few mA from the -12v supply, so the ULN regulator can be a suitable op amp
> with no external pass transistors.)
>
> Last time I bought them, I paid $25 for a lot of three HTAA-16W-A's.
>
> Best regards,
>
> Charles
>
>
> ___
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Re: [time-nuts] Anybody want a Thunderbolt power supply?

[Jerry O. Stern]

Charles, do you have the schematic for the HTAA-16W-A  ?  The KO4BB mod has 
limited info

Tnx

Jerry
k1...@arrl.net


-Original Message-
From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Charles 
Steinmetz
Sent: Wednesday, August 31, 2016 4:49 AM
To: time-nuts@febo.com
Subject: Re: [time-nuts] Anybody want a Thunderbolt power supply?

Nick wrote:>

> I’m going to shoot for <= 35 mV P-P. If you need better than that, 
> then it probably turns into a hybrid switching+linear system

It's been years since I played with Tbolts (as opposed to just using them), but 
as I recall there was no possibility whatever of getting the best results from 
any switching supply without at least one stage of linear "polishing."  In 
fact, everything I tried with initial switching regulation benefitted from two 
levels of linear polishing.  It was my conclusion that starting with a 
switching supply of any sort is a bad idea.

I found that for best performance the -12v supply, which feeds the DAC, needs 
to be about 1000 times better than what you are shooting for (i.e., low tens of 
uVp-p).  That surprised me, because I assumed there must be some internal 
regulation of the DAC supplies -- but it was what my testing showed.

Sure, a Tbolt will work with dirtier power than that, but for real time-nuts 
performance I consider an all-linear supply with an ultra-low-noise -12v rail 
to be absolutely necessary.  Since that is not very hard to provide, I see no 
reason to try to make do with less.

One low-cost solution is to wait for a cheap Power One HTAA-16W-A triple-output 
power supply to show up on ebay, and do a very minor modification to raise the 
+12v current limit (so it will handle the first moments of a cold start without 
current limiting) as detailed here:



That approach achieves excellent results -- close to the best you can do
-- with very little fiddling.  If one wants the very best performance, the -12v 
supply can be adjusted down to -16v or so to provide the headroom to add a ULN 
regulator or a capacitance multiplier.  (The Tbolt only draws a few mA from the 
-12v supply, so the ULN regulator can be a suitable op amp with no external 
pass transistors.)

Last time I bought them, I paid $25 for a lot of three HTAA-16W-A's.

Best regards,

Charles


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Re: [time-nuts] Anybody want a Thunderbolt power supply?

[Charles Steinmetz]

Nick wrote:>


I’m going to shoot for <= 35 mV P-P. If you need better than that, then it 
probably turns into a hybrid switching+linear system


It's been years since I played with Tbolts (as opposed to just using 
them), but as I recall there was no possibility whatever of getting the 
best results from any switching supply without at least one stage of 
linear "polishing."  In fact, everything I tried with initial switching 
regulation benefitted from two levels of linear polishing.  It was my 
conclusion that starting with a switching supply of any sort is a bad idea.


I found that for best performance the -12v supply, which feeds the DAC, 
needs to be about 1000 times better than what you are shooting for 
(i.e., low tens of uVp-p).  That surprised me, because I assumed there 
must be some internal regulation of the DAC supplies -- but it was what 
my testing showed.


Sure, a Tbolt will work with dirtier power than that, but for real 
time-nuts performance I consider an all-linear supply with an 
ultra-low-noise -12v rail to be absolutely necessary.  Since that is not 
very hard to provide, I see no reason to try to make do with less.


One low-cost solution is to wait for a cheap Power One HTAA-16W-A 
triple-output power supply to show up on ebay, and do a very minor 
modification to raise the +12v current limit (so it will handle the 
first moments of a cold start without current limiting) as detailed here:




That approach achieves excellent results -- close to the best you can do 
-- with very little fiddling.  If one wants the very best performance, 
the -12v supply can be adjusted down to -16v or so to provide the 
headroom to add a ULN regulator or a capacitance multiplier.  (The Tbolt 
only draws a few mA from the -12v supply, so the ULN regulator can be a 
suitable op amp with no external pass transistors.)


Last time I bought them, I paid $25 for a lot of three HTAA-16W-A's.

Best regards,

Charles


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Re: [time-nuts] Anybody want a Thunderbolt power supply?

[DaveH]

If low noise, that would simplify things here.

Dave
 

> -Original Message-
> From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf 
> Of Nick Sayer via time-nuts
> Sent: Tuesday, August 30, 2016 19:23
> To: Discussion of precise time and frequency measurement
> Subject: [time-nuts] Anybody want a Thunderbolt power supply?
> 
> A little board to generate -12 and +5 from a 15 watt 12 VDC 
> input wouldn't be too hard to design. If I put one out for 
> $25, would anyone like one?
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Re: [time-nuts] Sunrise, solar noon, sunset and the Equation of Time

[David J Taylor]

I recently added code to Lady Heather to precisely calculate the sun 
position, sunrise/solar noon/sunset times and the Equation of Time... Egad, 
what a deep, dark rabbit hole that leads one down.   And woe be unto thee 
that trusts any of the online calculators.  Results can be over 10 minutes 
off and nobody gives times down to the second.  Oh, and there's a half dozen 
different types of sunrise/sunset to consider.


The gold standard for those calculation is NREL's Solar Position Algorithm. 
It's awesome.  It's also awesomely complex.  Like 1300 lines of code and 
several thousand double precision operations and 300+ trig functions per 
result.   It also has a rather wonky license agreement. (and if your time 
zone is not Greenwich is can report the sunrise or sunset time for the 
previous/next day)


I finally settled on Grena's Algorithm 5 for sun position.  It only around 
100 lines long uses less than 20 trig function calls to calculate the sun 
position and produces results comparable to SPA for the years 2010 .. 2110.


Getting sunrise/sunset/solar noon from solar position is a bit more 
complicated.  I do binary searches and interpolations to find when the sun 
crosses the magic thresholds to within a second...  it takes about 300 lines 
of code and 60 sun position evaluations.  Lady Heather can now play sound 
files at sunrise, solar noon, sunset... your basic GPS disciplined rooster 
and church bells.


And, for the sundial crowd,  tomorrow is the day the Equation of Time 
crosses 0.0 seconds so get out and set your sundials...

___


Interesting, Mark, especially your comments about online calculators.  My 
WXtrack program computes many of the values you mention, so I would be 
interested to compare results.  It calculates positions for the moon as 
well.


 http://www.satsignal.eu/software/wxtrack.htm

Also runs under Linux/WINE.  I use routines from Dr TS Kelso.  You will be 
aware of the three different definitions of sunset, of course.


Cheers,
David
--
SatSignal Software - Quality software written to your requirements
Web: http://www.satsignal.eu
Email: david-tay...@blueyonder.co.uk
Twitter: @gm8arv 


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