Re: [time-nuts] OT: ExpressPCB (cross-post from volts-nuts)

[Herbert Poetzl]

On Fri, Dec 09, 2016 at 08:25:52PM -0800, Chris Albertson wrote:
> Lowest price I've found is BasicPCB.com They charge $3 per
> square inch for 2 layers with mask and legend. 

OSHpark charges $5 per square inch for the standard 2 layer
order (which include three boards, i.e. actually 3 square
inch or $5/3 per square inch) including mask and silk screen
on both sides, no limit to vias or general drill hits but
unfortunately no electrical check.

> Minimum is three boards of 1 square inch. So you actually 
> can place a $9 order with them. 

You can get a a lot lower with OSHpark there, I had orders
below 2 USD and they ship for free, worldwide.

> They are a USA based company.

OSHpark too.

> They accept standard Gerber files.   

Besides Gerbers, they also process KiCad and Eagle design
files.

> This is very impotent as a few others like PCBexpress make 
> you use their proprietary layout software and then you are
> locked into that company for production runs too.

Yes, nasty.

> You need a workflow that uses Gerber files.

Best,
Herbert


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Re: [time-nuts] GPS antenna selection

[Herbert Poetzl]

On Thu, Aug 04, 2016 at 06:26:28PM -0400, Bob Camp wrote:
> Hi

Hey Bob!

>> On Aug 4, 2016, at 5:29 PM, Herbert Poetzl  wrote:

>> Dear fellow time-nuts!

>> I'm currently investigating my options regarding 
>> GPS antennae (of course for time related purposes)
>> and I'm really confused by the variety they come
>> in ... (my apologies in advance for the long post).


>> Setting:

>> I'm living in a three storey house with a sloped
>> roof, a covered balcony and a larger garden with
>> huge trees on the Austrian countryside (Europe).

>> I've walked around with my smartphone (older one)
>> and I get a GPS position fix within 35s in the 
>> garden (nine satellites shown), within 100s on 
>> the balcony (also nine satellites), and not a
>> single satellite can be seen indoors.

>> The obvious choice would be to put the antenna on
>> top in the middle of the slanted roof for a perfect
>> sky view, but this brings a number of problems as
>> the roof is very hard to reach and quite high.

>> I have my 'lab' at the floor where the balcony is,
>> so I'm considering putting an antenna there and
>> run about 5-15m of coax cable to the GPS receiver.
>> The advantage there is that the antenna would be
>> somewhat protected (it still gets very hot during
>> summer and very cold during winter, but no rain
>> and no snow) and easy to reach for maintenance.

>> The third alternative would be to put the antenna
>> somewhere in the garden and have a rather long
>> cable running to the house and up to my lab.


>> Antennae:

>> Looking on eBay and Amazon shows a huge pricerange 
>> for active GPS antennae with and without cable. 

>> It seems to start at about 10 bucks with rather
>> small black boxes [1] designed for cars, probably 
>> containing a 25x25 ceramic GPS antenna and an 
>> amplifier, progresses over very interesting out-
>> door constructions for boats and whatnot [2] in 
>> the 20-100 bucks range and finally tops with high 
>> end devices [3] way above 100 bucks.

>> The information about the cheap devices is usually
>> very scarce, but typically boils down to:

>> 1575.42 +/- 5MHz 
>> 24-28dB LNA Gain with 10-25mA at (3-5V)

>> 7dB f0 +/- 20MHz
>> 20dB f0 +/- 50MHz
>> 30dB f0 +/- 100MHz

> That’s the spec on the interference rejection filter. 
> Tighter is better as long as it still passes the 
> desired signal(s). 

Understood!

>> They seem to use RG174 and come with SMA as well
>> as BNC connectors (and a number of others as well).

> The better ones will have a TNC connector on them

Hmm, I had to google TNC (Threaded Neill-Concelman).
Is it worth the trouble in the < 2GHz range?

>> The mid range devices seem to use larger antennae
>> with smaller tolerances (+/- 1MHz) and larger
>> voltage ranges for the amplifier (3-13V).


>> Questions:

>> - What are the key specifications which need to
>>   be verified before buying a GPS antenna?

> You want one that is designed for permanent outdoor 
> use. 

> That eliminates the $10 car mounts. 

Even under somewhat protected conditions like on the
covered balcony?


> These days, I’d get one that does both GPS and GLONASS

Makes sense.


>> - How can they be compared based on incomplete
>>   specifications?

> They can’t. It’s just luck. The ones you see for 
> about $40 and up that are designed for mast mounting 
> are usually pretty good.

Okay, thanks!

>> - Is a place on the roof or in the garden worth
>>   the trouble over the covered balcony?

> The real question is how much of a sky view you get. 

> Ideally you would like a clear view of the sky from 
> about NE clear around to NW (270 degrees). 

That would opt for the balcony, as it faces north
and extends the slanted roof, so basically clear
view from NE to NW down to the horizon.

> You also would like to be able to “see” down to within 
> 10 degrees of the horizon over that range. 

> The segment from E to W (180 degrees) is pretty
> important. 

> Being able to see to within 30 degrees of the horizon 
> is also pretty important.


>> - Are there any typical pit-falls or general
>>   tips and tricks regarding mounting and cable
>>   connection to the receiver?

> Some receivers put out +12V, most antennas don’t like 
> +12 and want +5. 

> Some modern antennas will only handle +3.3V.

> If you have a long run to the antenna, feed line loss 
> is what matters. 

> To some degree you can cope with this by buying an
> antenna that has a higher gain amp in it. 

> They range from about 21 db to about 50 db. 

> Y

[time-nuts] GPS antenna selection

[Herbert Poetzl]

Dear fellow time-nuts!

I'm currently investigating my options regarding 
GPS antennae (of course for time related purposes)
and I'm really confused by the variety they come
in ... (my apologies in advance for the long post).


Setting:

I'm living in a three storey house with a sloped
roof, a covered balcony and a larger garden with
huge trees on the Austrian countryside (Europe).

I've walked around with my smartphone (older one)
and I get a GPS position fix within 35s in the 
garden (nine satellites shown), within 100s on 
the balcony (also nine satellites), and not a
single satellite can be seen indoors.

The obvious choice would be to put the antenna on
top in the middle of the slanted roof for a perfect
sky view, but this brings a number of problems as
the roof is very hard to reach and quite high.

I have my 'lab' at the floor where the balcony is,
so I'm considering putting an antenna there and
run about 5-15m of coax cable to the GPS receiver.
The advantage there is that the antenna would be
somewhat protected (it still gets very hot during
summer and very cold during winter, but no rain
and no snow) and easy to reach for maintenance.

The third alternative would be to put the antenna
somewhere in the garden and have a rather long
cable running to the house and up to my lab.


Antennae:

Looking on eBay and Amazon shows a huge pricerange 
for active GPS antennae with and without cable. 

It seems to start at about 10 bucks with rather
small black boxes [1] designed for cars, probably 
containing a 25x25 ceramic GPS antenna and an 
amplifier, progresses over very interesting out-
door constructions for boats and whatnot [2] in 
the 20-100 bucks range and finally tops with high 
end devices [3] way above 100 bucks.

The information about the cheap devices is usually
very scarce, but typically boils down to:

 1575.42 +/- 5MHz 
 24-28dB LNA Gain with 10-25mA at (3-5V)

 7dB f0 +/- 20MHz
 20dB f0 +/- 50MHz
 30dB f0 +/- 100MHz

They seem to use RG174 and come with SMA as well
as BNC connectors (and a number of others as well).

The mid range devices seem to use larger antennae
with smaller tolerances (+/- 1MHz) and larger
voltage ranges for the amplifier (3-13V).


Questions:

 - What are the key specifications which need to
   be verified before buying a GPS antenna?

 - How can they be compared based on incomplete
   specifications?

 - Is a place on the roof or in the garden worth
   the trouble over the covered balcony?

 - Are there any typical pit-falls or general
   tips and tricks regarding mounting and cable
   connection to the receiver?

Many thanks in advance and my apologies again for
the rather lengthy post. Please feel free to point
me to previous discussion regarding this topic.

All the best,
Herbert


[1] 
http://www.ebay.com/itm/99-Good-GPS-Antenna-SMA-Screw-Needle-10m-Super-Signal-Navigation-DVD-Antenna-/171802461614
https://www.amazon.com/Waterproof-Active-Antenna-28dB-Gain/dp/B00LXRQY9A

[2] 
http://www.ebay.com/itm/Standard-Horizon-XUCMP0014-GPS-Antenna-f-CP150-CP160-CP170/331364914004
https://www.amazon.com/Garmin-010-12017-00-GPS-GLONASS-Antenna/dp/B00EVT2HSE

https://www.amazon.com/SUNDELY®-External-Marine-Antenna-connector/dp/B00D8WAVTC

[3] http://www.ebay.com/itm/NEW-FURUNO-GPA018-Gps-dgps-Antenna-/182223355414
https://www.amazon.com/Garmin-nmea-2000-orders-over/dp/B0089DU96A

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Re: [time-nuts] RS232 / GPS interface/prototyping board

[Herbert Poetzl]

On Tue, Jun 14, 2016 at 07:19:54AM -0700, Nick Sayer via time-nuts wrote:
> That’s not a USB chip, it’s an RS-232 level converter.

> I am not aware of any USB 2 UART devices (that doesn’t
> necessarily mean much). They just don’t need to be that fast.

All modern FTDIs are USB 2.0 (for example the FT232R,
FT2232H and FT4232H) because they also allow for other
types of data transfer besides the UART which require
USB 2.0.

Best,
Herbert

>> On Jun 13, 2016, at 11:53 PM, Gary E. Miller  wrote:

>> Yo Mark!

>> On Tue, 14 Jun 2016 00:53:10 +
>> Mark Sims  wrote:

>>> The 1PPS signal is
>>> routed to the RS-232 connector via the MAX232A, 

>> Why did you use a USB 1.1 chip instead of a USB 2.0 chip?  The PPS
>> performance is much better with the Hi Speed chips.

>> 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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Re: [time-nuts] HP5065A Super upgrade

[Herbert Poetzl]

On Fri, Jun 10, 2016 at 05:05:28PM +0200, tim...@timeok.it wrote:
> Hi all,

> I have posted here my experience with the installation of the
> band pass filter in front of the lamp of the HP5065A.

> http://www.timeok.it/wp/wp-content/uploads/2015/08/HP5065A-Super-upgrade-v-1.4.pdf

Hmm, on the first page for 100 seconds it says:

Before: 0.5*10^-13 (which would be 5*10^-14)3 
After: 6.0*10^-14 (or 0.6*10^-13)

So it effectively got worse on the long term?

Thanks,
Herbert

> Luciano

> tim...@timeok.it
> Message sent via Atmail Open - http://atmail.org/
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Re: [time-nuts] Microchip PIC CTMU

[Herbert Poetzl]

On Fri, May 13, 2016 at 07:51:07PM +0200, Attila Kinali wrote:
> On Fri, 13 May 2016 07:36:10 -0400
> Bob Camp  wrote:

>> Given that a “real” TDC is a resistor and capacitor
>> attached to a FPGA pin (plus the ADC) the cost of doing it
>> better is not all that much. You can get down to a few hundred
>> ps without a lot of crazy effort ( still using the MCU ADC).

> The PICTIC II did 250ps resolution with an effective resolution
> of 680ps[1].

> The upgraded version III had IIRC a resolution of ~25ps with
> better than 100ps achieved. Eventhough the PICTIC III design is
> a bit more involved than then II, it's still relatively simple
> (it uses more stable current sources, buffer opamps, external
> ADCs and an active offset compensation scheme).

Hmm, sounds interesting ...
Is there a PICTIC III schematic somewhere?

Thanks in advance,
Herbert

>   Attila Kinali

> PS: Does anyone know what happend to Richard McCorkle? I haven't heard
> of him in ages.

> [1] http://www.ke5fx.com/pictic.htm

> -- 
> Reading can seriously damage your ignorance.
>   -- unknown
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Re: [time-nuts] [Announce] Simulation software for powerlaw noise and PTP clock synchronization

[Herbert Poetzl]

On Thu, Apr 14, 2016 at 10:18:22PM +0200, Wolfgang Wallner wrote:

> Dear Timenuts community,

Wolfgang,

> I would like to announce the public availabilty of two software projects 
> which I have been working on for my master thesis:

> * LibPLN: a portable C++ library for the efficient simulation
>   of Powerlaw Noise (PLN)
> * LibPTP: a simulation framework based on the OMNeT++ network
>   simulation environment, for the simulation of the Precision
>   Time Protocol (PTP) as it is specified in IEEE 1588-2008

Thanks!

> Getting started:
> --

> Both software project are available as open source from my Github 
> account: https://github.com/w-wallner
> The readme files present on the Github page should give you an idea on 
> how to get started using the individual components.


> License:
> --

> All code is licensed using open source licenses.
> Most parts of the software are licensed as GPLv3, some parts use the 
> GPLv2 and BSD licenses.
> See the respective COPYING files for details.

Very appreciated!

> Detailed documentation:
> --

> A detailed description of all design design decisions and how
> the fundamental concepts of the libraries work is contained in
> my master thesis:

> Simulation of Time-synchronized Networks using IEEE 1588-2008, 
> 2016, Vienna University of Technology

> As of this writing (April 2016), it is not yet published, the expected 
> publication date will be May or June 2016.

Please let me/us know when there is an electronic
Version available.

> I hope these projects can be useful for some of you :)
> In case you have any questions, feel free to ask.

Thanks again,
Herbert

> Kind regards,
> Wolfgang Wallner
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Re: [time-nuts] Advise on building a DIY GPSDO?

[Herbert Poetzl]

exact. It is  simply a free 
>>> running TCXO
>>> that happens to be in a GPS module. It has a  basic accuracy of +/- 1 ppm 
>>> or something 
>>> similar. It is no better or worse  than any other TCXO you could buy. 

>>> To make it accurate they have two  choices:

>>> 1) Put a voltage control input on the TCXO and turn it into a  TCVCXO, then 
>>> lock it up 
>>> with a loop.

>>> 2) Let the oscillator free run  and “fix up” the output.

>>> For a variety of reasons, none of the small  GPS modules go with option 
>>> number 1. They 
>>> all go with option number 2. The  24 Hz error on the (maybe)  24 MHz gets 
>>> taken out by dropping
>>> 24 edges  every second. That’s not a lot of edges, it’s not going to turn 
>>> the output  into absolute 
>>> garbage you can see on a scope. It is plenty of nonsense to  mess up a 
>>> radio or a piece of test gear. 

>>> One easy way to look at it:  You have ~1 ppm jitter on the output (in the 
>>> example of 1 ppm of error). A  
>>> phase locked GPSDO with only simple filtering of a 1 pps would get you  
>>> down to 0.01 ppm of jitter. 
>>> A sawtooth corrected 1 pps would get you to  0.01 ppm. A good filter would 
>>> get you to <0.1 ppm.
>>> Yes, I’m using a  very hand waving definition of jitter here, but it does 
>>> illustrate the point.  You could 
>>> look at the jitter on the pulse drop as 0.04 ppm.  

>>> Bob



>>>> Mike

>>>>> That can  be filtered out with a RF filter. The same is true with a 
>>> (somewhat  more
>>>>> complex) filter on the 10 MHz output.

>>>>> In  addition to the “big” RF spurs, you get a low frequency component 
>>> to the  output
>>>>> modulation. You are “phase hitting” the output eight times  a second. 
>>> That gives you
>>>>> an 8 Hz sideband along with the further  removed stuff. Since it’s not 
>>> simple / clean
>>>>> phase modulation,  there are more sidebands than just the few mentioned 
>>> above. 

>>>>> What messes things up even more is that you never are quite doing  one 
>>> ppm. You are doing
>>>>> corrections like 0.12356 ppm this second  and 0.120201 ppm the next 
>>> second. 
>>>>> The pattern of pulse drop and  add is not as simple as you might hope. 
>>> The low 
>>>>> frequency part of  the jitter (and it will be there) is no different 
>>> than the noise  on
>>>>> a 1 pps output. You still need to do very long time constant  (or very 
>>> narrow band)
>>>>> filtering to take it out. 

>>>>> Bob

>>>>>> On Apr 8, 2016, at 7:06 AM, Herbert  Poetzl  
>>> wrote:

>>>>>> On  Mon, Apr 04, 2016 at 06:07:54PM -0700, Alexander Pummer  wrote:
>>>>>>> and it is relative easy to make 10MHz from 8MHz  with analog
>>>>>>> frequency manipulation, which generates less  jitter

>>>>>> Could you elaborate on this a little  if time permits? 
>>>>>> I'm more a 'digital person' but it sounds  interesting.

>>>>>> Thanks in  advance,
>>>>>> Herbert

>>>>>>> 73

>>>>>>> On 4/4/2016 4:27 PM, Attila Kinali  wrote:
>>>>>>>> On Mon, 4 Apr 2016 17:56:29  -0400
>>>>>>>> Bob Camp   wrote:

>>>>>>>>> The variable frequency  output on the uBlox (and other) GPS
>>>>>>>>> receivers has  come up many times in the past.

>>>>>>>>> If you dig into the archives you can find quite a bit  of
>>>>>>>>> data on the (lack of) performance of the  high(er) frequency
>>>>>>>>> outputs from the various GPS  modules. They all depend on
>>>>>>>>> cycle add / drop at  the frequency of their free running TCXO.
>>>>>>>>> Regardless of the output frequency, that will put a *lot*  of
>>>>>>>>> jitter into the output.
>>>>>>>> That's why you should put the output frequency of the ublox  modules
>>>>>>>> to an integer divisor of 24MHz. Ie 8MHz works  but not 10MHz.

>>>>>>>>       Attila Kinali


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Re: [time-nuts] Advise on building a DIY GPSDO?

[Herbert Poetzl]

On Fri, Apr 08, 2016 at 06:13:07PM -0400, Bob Camp wrote:
> Hi

> If you start from a 24 MHz TCXO (different modules use
> different TCXO’s):

> On an 8 MHz output, most of the time you divide by three. 

> On a 10 MHz output, you need to divide by 2.4. 
> The net result is that you divide by 2 sometimes and 3 
> other times.   

> In the 10 MHz case, there is a *lot* of energy at 12 MHz 
> and 8 MHz, along with the 10 MHz output. 

> In the 8 MHz case, most of the RF energy is at 8 MHz.

Thanks for the input, but alternating between dividing
by two and three doesn't really sound like "analog 
frequency manipulation" to me.

Maybe I'm completely wrong here, maybe I just need to
see an analog circuit which does this.

Best,
Herbert

> 

> To correct the output by 1 ppm on the 8 MHz output, you 
> need to either drop or add one pulse out of every million
> pulses. Effectively you divide the 24 MHz by 2 or by 4 
> when you do that. 

> You get a bit of 12 MHz or a bit of 6 MHz as a result.
> That can be filtered out with a RF filter. 

> The same is true with a (somewhat more complex) filter 
> on the 10 MHz output.

> In addition to the “big” RF spurs, you get a low frequency 
> component to the output modulation. 

> You are “phase hitting” the output eight times a second. 

> That gives you an 8 Hz sideband along with the further 
> removed stuff. Since it’s not simple / clean phase 
> modulation, there are more sidebands than just the few 
> mentioned above.

> What messes things up even more is that you never are quite
> doing one ppm. You are doing corrections like 0.12356 ppm  
> this second and 0.120201 ppm the next second. The pattern 
> of pulse drop and add is not as simple as you might hope. 

> The low frequency part of the jitter (and it will be there) is
> no different than the noise on a 1 pps output. You still need
> to do very long time constant (or very narrow band) filtering
> to take it out.

> Bob

>> On Apr 8, 2016, at 7:06 AM, Herbert Poetzl  wrote:

>> On Mon, Apr 04, 2016 at 06:07:54PM -0700, Alexander Pummer wrote:
>>> and it is relative easy to make 10MHz from 8MHz with analog
>>> frequency manipulation, which generates less jitter

>> Could you elaborate on this a little if time permits? 
>> I'm more a 'digital person' but it sounds interesting.

>> Thanks in advance,
>> Herbert

>>> 73

>>> On 4/4/2016 4:27 PM, Attila Kinali wrote:
>>>> On Mon, 4 Apr 2016 17:56:29 -0400
>>>> Bob Camp  wrote:

>>>>> The variable frequency output on the uBlox (and other) GPS
>>>>> receivers has come up many times in the past.

>>>>> If you dig into the archives you can find quite a bit of
>>>>> data on the (lack of) performance of the high(er) frequency
>>>>> outputs from the various GPS modules. They all depend on
>>>>> cycle add / drop at the frequency of their free running TCXO.
>>>>> Regardless of the output frequency, that will put a *lot* of
>>>>> jitter into the output.
>>>> That's why you should put the output frequency of the ublox modules
>>>> to an integer divisor of 24MHz. Ie 8MHz works but not 10MHz.

>>>>Attila Kinali


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Re: [time-nuts] Advise on building a DIY GPSDO?

[Herbert Poetzl]

On Mon, Apr 04, 2016 at 06:07:54PM -0700, Alexander Pummer wrote:
> and it is relative easy to make 10MHz from 8MHz with analog
> frequency manipulation, which generates less jitter

Could you elaborate on this a little if time permits? 
I'm more a 'digital person' but it sounds interesting.

Thanks in advance,
Herbert

> 73

> On 4/4/2016 4:27 PM, Attila Kinali wrote:
>> On Mon, 4 Apr 2016 17:56:29 -0400
>> Bob Camp  wrote:

>>> The variable frequency output on the uBlox (and other) GPS
>>> receivers has come up many times in the past.

>>> If you dig into the archives you can find quite a bit of
>>> data on the (lack of) performance of the high(er) frequency
>>> outputs from the various GPS modules. They all depend on
>>> cycle add / drop at the frequency of their free running TCXO.
>>> Regardless of the output frequency, that will put a *lot* of
>>> jitter into the output.
>> That's why you should put the output frequency of the ublox modules
>> to an integer divisor of 24MHz. Ie 8MHz works but not 10MHz.

>>  Attila Kinali


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Re: [time-nuts] A new member & PN test set

[Herbert Poetzl]

On Sun, Mar 27, 2016 at 11:25:36PM +0300, Oleg Skydan wrote:
> Hi list,

> I am in a process of making a low noise frequency
> synthesizer for the 1st LO for my new DSP HF transceiver
> (http://neon.skydan.in.ua). This list is not directly 
> related to my project, but I found a lot of useful 
> information in this list - thanks for all contributors!

> I see a discussion regarding "$40 phase noise test set". 
> I have built one and already use it for several months. 

> It is a great help in design process (I am not "blind" 
> anymore :) ). 

> If somebody is interested I can share all the infor-
> mation about it.

Yes, please do! I'm interested!

Thanks,
Herbert

> Best wishes!
> Oleg 

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Re: [time-nuts] Prescaler

[Herbert Poetzl]

On Sun, Mar 27, 2016 at 07:45:23PM +, Bob Albert via time-nuts wrote:
> Does anyone know of an inexpensive prescaler for a counter 
> that goes beyond 2 GHz?  

A few years ago, I was looking for something cheap to build
a PIC based GHz counter and I stumbled over the LMX23xx
chips from TI (PLL frequency synthesizers), which have
a prescaler built in.

Specifically the LMX2322 and LMX2364, which are quite cheap
and easy to use (older ones available on eBay, the newer 
ones at your favorite distributor).

http://www.ti.com/lit/ds/symlink/lmx2364.pdf

> I would actually like to find a kit but everything seems 
> a bit pricy.  

I have designed breakout boards for both, so if that looks
like something which could be useful to you, just drop me
a note and I'll make them available.

Best,
Herbert

> I currently have capability of 500 MHz and that will 
> stretch to about 700 with care.  

> So a divide by 10 would be ideal.

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Re: [time-nuts] high rev isolation amps

[Herbert Poetzl]

On Sat, Mar 26, 2016 at 10:33:12PM -0400, John Ackermann N8UR wrote:

> If there is enough interest, TAPR could consider doing a
> production run.

> If not, I'll release the design package including Gerbers.

I'd be very interested in the design files, i.e.
schematic and gerbers regardless of the TAPR
production run.

> I'll try to get some better documentation put together in the
> next week or two, and figure out a way to create a sign-up list
> for people who are interested. We'd have to have a minimum
> number of committed orders before kicking things off.

Thanks in advance,
Herbert

> John
> 

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Re: [time-nuts] low noise multiplication to 100 MHz

[Herbert Poetzl]

On Tue, Jan 26, 2016 at 06:57:54AM +, Mark Sims wrote:
> Actually not hard to do... lay out circuit board (free version
> of Eagle), have boards fab'd at Oshpark.com or your favorite
> Chinese proto shop (I like gojgo.com). Have solder paste
> stencil made at oshstencils.com. Squeege solder paste down with
> a credit card. Place components by hand. Reflow board with a
> modified toaster oven, electric skillet, hot air tool, etc.

Because I build and solder SMD boards on a regular basis,
I would like to add a few hints and tricks here which can 
simplify the task significantly:

For one-sided designs, the skillet method is really simple
and if the temperature is right, gives excellent results.

There are a bunch of ceramic heater elements (PTC) on eBay
and they often provide the perfect temperature stability
without the need for actual regulation (i.e. connect them
to a current limited power supply and it will reach a 
specific temperature at a given current).

As they are small, they work perfectly under a microscope
and you can not only watch the solder reflow, you can also
move the parts around in the liquid solder.

Most SMD components can also be soldered by hand with a
soldering iron, which doesn't even have to have a delicate
tip because there is an easy way with the help of (usually
red) thixotropic glue.

You first place a little dot or line of glue where the SMD
component will go (obviously not on the pads but between :) 
and then you place the component (down to 0201 imperial) 
with tweezers or a vacuum pick-up tool (doesn't need to be
extremely precise at this point) and now you can move the 
part into its final position with the help of an acupuncture 
needle.

Once all the components have been placed (the glue stays
liquid for several hours, probably days) and oriented/aligned
perfectly, you heat up the entire board to 120-160°C for
about 10 minutes which polymerizes the glue and thus fixes 
the parts in place.

You can then apply a good amount of solder on all the tiny 
pads to make sure that they are well connected. Heating the
entire PCB to around 150-180°C will help a lot and usually
doesn't harm the board or components (iron temperature can
be as low as 280°C which reduces the danger of overheating
dramatically). Do not worry about accidential bridges and
excessive solder, this will be fixed in the next step.

Once the parts have been soldered in place, you get a solder
wick (I prefer to use one of those highly flexible silicone
wires with hundreds of tiny conductors - you need to strip
it down to the copper wires first) and some flux to remove 
excessive solder from the joints.

After that, clean up the board (i.e. remove flux and other
stuff) with a flux remover or alcohol (isopropanol).

Here a few examples what can be done without hot air gun or 
reflow oven:

http://vserver.13thfloor.at/Stuff/AXIOM/pmod_assembled_top_600dpi.png
http://vserver.13thfloor.at/Stuff/AXIOM/pmod_assembled_bottom_600dpi.png
http://vserver.13thfloor.at/Stuff/AXIOM/BETA/pmod_clock_nosma.png
https://wiki.apertus.org/images/4/42/Axiom_Beta_Plugin_Module_1x_HDMI_v0.4_BOT.jpg
https://wiki.apertus.org/images/c/c0/BetaSensorBoardZIF_0.18_2.jpg
https://wiki.apertus.org/images/d/da/BetaMainboard_0.32_BOTTOM.jpg
http://vserver.13thfloor.at/Stuff/AXIOM/BETA/axiom_beta_power_board_v0.18_r1.0_fix01.jpg
http://vserver.13thfloor.at/Stuff/AXIOM/BETA/axiom_beta_power_board_v0.18_r1.0_fix02.jpg

And some links to the mentioned helpers:

http://www.ebay.com/itm/PTC-heating-element-100W-AC-DC-12V-constant-temperature-60-21mm-/151727264825
www.ebay.com/itm/AC-DC-12V-40W-PTC-Heater-Element-Thermostat-Heating-Plate-for-Warmer-Hot-Melter-/252212420224
www.ebay.com/itm/1Pc-40g-30mL-SMD-SMT-PCB-BGA-IC-Stencil-Paste-Dispenser-Red-Glue-Effective-Work-/321845571034
http://uk.farnell.com/multi-contact/60-7180-21/litze-blank-hochflex-0-5qmm-tpe/dp/135276
http://www.ebay.com/itm/5pcs-BGA-SMD-Soldering-Paste-Flux-Grease-Volume-10cc-RMA-223-/281358896876
http://uk.farnell.com/pro-power/ppc120/propower-flussmittelentfernerspray/dp/1736213

If you have any problems or general questions, do not
hesitate to email me.

Best,
Herbert

> If you want to get anywhere in electronics these days, you
> really need to get set up to do simple SMD work. It's not hard
> or expensive. The days of point to point wiring of vacuum
> tubes to terminal strips be looong gone. Through-hole and DIP
> packages are not far behind.
> 
> ---
> > There are other neat parts out there but again who is able to 
> solder  them.   
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Re: [time-nuts] GPS down converter question

[Herbert Poetzl]

On Thu, Dec 03, 2015 at 01:53:25PM +0100, Attila Kinali wrote:
> On Wed, 2 Dec 2015 21:12:42 -0500
> Ian Stirling  wrote:

>>   Here's a video of Dave Jones soldering a QFN chip.
>> http://www.eevblog.com/2013/01/08/eevblog-408-schmart-board-0-4mm-qfn-smd-soldering/

> Unfortunately, this technique only works if you don't have
> a ground pad to solder, which most of the RF chips have.

If you plan for hand soldering, this is one of the easier
problems to solve: just make a somewhat larger via where
the ground pad is so that you can easily solder and fill
it from the other side.

> Actually, a lot of them have no other ground pins than the
> ground pad. 

> Also, the long traces for the breakout are prohibitive 
> for RF stuff. 

No need for long traces, about 1mm (0.04") should be more
than enough to solder the traces to the QFN chip.

Been there, did that, worked just fine :)

> Even if you just run it at 70MHz, the chip is designed for 
> GHz operation, which means you have to treat all signals 
> as if they were operating there. 

> Otherwise you will have some funny effects.

>   Attila Kinali

> PS: Please be aware that Dave Jones is often borderline wrong
> with what he presents in his videos. So take them with a grain
> of salt and check any "facts" independently before relying on
> them.

I totally agree here.

Best,
Herbert

> -- 
> It is upon moral qualities that a society is ultimately founded. All 
> the prosperity and technological sophistication in the world is of no 
> use without that foundation.
>  -- Miss Matheson, The Diamond Age, Neil Stephenson
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Re: [time-nuts] GPS down converter question

[Herbert Poetzl]

On Tue, Dec 01, 2015 at 08:33:05PM -0500, paul swed wrote:
> Digikey was a strike out with 1 filter for 86 cents but 
> order was 1000 units.

Sorry, but could you point me to the filter in question
please, I couldn't find anything on digikey, but probably
I was searching for the wrong keywords.

Thanks in advance,
Herbert

> Mouser however has a wide assortment very reasonable and 
> by the single units.

> Hardest thing will be soldering them.

> Regards
> Paul
> WB8TSL
> 
> 
> On Tue, Dec 1, 2015 at 8:29 PM, paul swed  wrote:
> 
> > Hello to the group have indeed done the 1575 down to 35.42 to 75.42 and
> > upconverter trick.
> > Thats what I used for 2-3 years now and thought it was time to move beyond
> > that approach. Especially due to the earlier conversation on old receivers
> > and that they should still work just fine if you do not care about the date.
> >
> > I actually have 2 versions of the 35 to 75 converter. One using an odetics
> > down converter and another using a starlink gps receiver. Both have 35.42
> > MHz IFs. Old stuff you can get a soldering iron into.
> >
> > No intention to put this on the tower and mini-circuits makes a good BPF
> > for the 75 MHz IF. Since I will believe the actual antenna has a 1571
> > filter in it I was thinking of skipping it down in the shack.
> >
> > Will see what digikey and mouser has in the way of filters and if
> > inexpensive may buy one. I keep thinking I may actually have one also.
> > Thanks again everyone.
> > Paul
> > WB8TSL
> >
> > On Tue, Dec 1, 2015 at 7:53 PM, Alex Pummer  wrote:
> >
> >> for 70MHz it does not hurt to match the cable to the filter at the
> >> antenna unit [down converter]  end  and also match the filter at the
> >> receiver upconverter end, the cable will pick up enough noise to overdrive
> >> the 70 something receiver's input  [ the "outside" field will drive a
> >> current in the cable's shield, but not in the center conductor, that
> >> current causes noise voltage between the two end of the cable's shield
> >> which will end up at the input of the receiver, therefore it need to be
> >> filtered out before it hits the mixer..also the down converter's LO's
> >> reference is sensitive to the noise which the cable will pick up [ will
> >> cause phase noise ], therefore it needs to be filtered .
> >> That down up converter system is an interesting project but it is not
> >> that simple as it looks
> >> 73
> >> KJ6UHN
> >> Alex
> >>
> >>
> >>   On 12/1/2015 2:57 PM, Bob Camp wrote:
> >>
> >>> Hi
> >>>
> >>> Here’s sort of a backwards look at it:
> >>>
> >>> Do you *need* an IF filter in the downconverter? By that I’m asking
> >>> about a
> >>> filter better than a simple LC tank. Did they put the filter in the
> >>> downconverter
> >>> or in the main box? I would think that putting a fancy filter up by the
> >>> antenna
> >>> would have been a less likely thing to do than putting it down in the
> >>> main box.
> >>>
> >>> Bob
> >>>
> >>>
> >>> On Dec 1, 2015, at 9:48 AM, paul swed  wrote:
> 
>  Thanks everyone. The Meinberg is nice and maybe available from Ebay by
>  Alex's link. But its 35.42 much as the Odetics down converter. I am
>  looking
>  to create a 75.42 Mhz IF.
>  Mini-circuits makes just the right parts. But had several IF bandwidths
>  available.
>  So will go with the 2 or so MHz filter as suggested.
> 
>  I have the typical GPS better quality high gain antenna 1/2" Heliax
>  feed to
>  a low noise gain block that makes up for the loss of a 8 X splitter.
>  I may add a 1575 filter ahead of the 10 db amplifier and then hit the
>  mixer. I think I have a filter. I actually question that I need the
>  filter
>  or 10 db amp. May build without it to see what happens. Can easily add
>  it.
>  The LO will be a mini-circuits dsn-2036 followed by a 10 db amp to drive
>  the mixer another mini-circuit DBM. The IF drives a bpf-a76+ and then
>  will
>  follow that with 30 db of gain at 75 MHz.
>  At least thats my thinking.
>  Regards
>  Paul
>  WB8TSL
> 
>  On Tue, Dec 1, 2015 at 1:36 AM, Magnus Danielson <
>  mag...@rubidium.dyndns.org
> 
> > wrote:
> > Hi,
> >
> > This is a side-track to Pauls original question, but maybe a nice
> > little
> > point to make now that Peter touched on the subject.
> >
> > To elaborate a little on C/A and multipath surpression.
> > The multipath surpression of the receiver depends on code rate,
> > bandwidth
> > and correlator spacing. P-code is able to surpress more, and the C/A
> > code
> > errors look about the same as the P-code, but scaled accordingly.
> > Increasing the bandwidth helps to reduce the C/A errors, but taking the
> > next step of using narrow correlators further reduces the error. This
> > is
> > shown already in the classical Spiliker book, but further readings from
> > Novate

Re: [time-nuts] RS-232 interfacing

[Herbert Poetzl]

On Mon, Aug 05, 2013 at 06:35:25AM -0700, M. Simon wrote:
> A while back some of the folks on the list were discussing
> RS-232 interfacing. 

> I may have something useful for those of you still wrestling
> with the problem. An RS-232 interface (Male or Female DB-9)
> that can take any voltage from 1.8 to 5V (nominal) and turn 
> it into full RS-232 levels at 230,400 baud or less. 

> It produces +/- 10V RS-232 levels (nominal - about +/- 8V
> actual).  

> You can configure the board for DTE or DCE with a jumper 
> field (a header on .1" ctrs - so you can use jumper shorts). 

> All the usual control signals are wired on the PCB except 
> for RI. 

> There are holes available for that though. 
> It requires a 5V supply.

> The design (schematics and parts list) is available at 
> http://spacetimepro.blogspot.com/2013/07/ttl-to-rs-232-db9-m.html 
> and you can order bare boards if that would be of use to you. 

> I also have links there to the RS-232 wiki. 
> And a few other useful things.  

Please don't take this the wrong way (I'm sure you've put
some efford into the design and I'm glad that you provide
the schematic and layout as well) but I have to add a few
constructive comments on the choice of components as well
as the entire design:

 - The HIN211 from Intersil
   * low data rate 120kbit/s max
   * Capacitor Charge Pump (noise)
   * requires 5V input for 10V swing

There are plenty of charge pump based, fully rs-232 compliant
interface chips (intersil, maxim, ti, analog devices) which
work with 3.3V and manage up to 1Mbaud, and if you want to
avoid the charge pump (for noise reasons) you can pick the
version with +/-12V inputs.

 - The SN74LVC2T45CTR or similar
   * 20ns/V rise and fall
   * 4 chips are required

There are a number of level translators designed for uni
and bidirectional translation between 0.8-5V and 3.3V
which handle 7/8 or more lines in a single device.
(note: no bidirectional translation is required for rs-232)

best,
Herbert

PS: if you need part numbers, just let me know, I'm sure 
I can dig out a bunch from my previous projects.

> Simon

> Engineering is the art of making what you want from what 
> you can get at a profit.
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Re: [time-nuts] What was 50.791095 MHz used for?

[Herbert Poetzl]

On Tue, May 28, 2013 at 08:58:19PM -0700, ed breya wrote:
> Does anyone know what 50.791095 MHz was used for? 

No idea, but playing around with the number resulted in:

50.791095 * 20 / 9 = 1128691

which is a prime :)

best,
Herbert

> I assume it was some sort of telecom clocking rate - 
> perhaps obsolete. 

> I serendipitously discovered that I have some VCXO modules 
> of this frequency, that will likely solve a problem on one 
> of my projects. I'm now curious about what they may have 
> been used for, and if that is a "standard" frequency that 
> will be available for future use.  

> Online searching seems to indicate it is very common, but 
> doesn't say what for.

> Ed

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Re: [time-nuts] Selecting a Microcontroller

[Herbert Poetzl]

On Sun, May 26, 2013 at 11:38:35AM -0600, Brent Gordon wrote:
> The two threads here, "Good (cheap) PIC chip choice for
> project?" and "Follow-up question re: microcontroller  
> families" have a lot of good information. 

> A more organized approach is available at the Digi-Key/Design  
> News Continuing Education Center which has several 
> free courses on microcontroller basics and selecting a 
> microcontroller. 

> You download a Powerpoint presentation and follow along 
> to an audio stream.

Does it require registration or am I just not seeing the
downloads on the linked pages?

thanks,
Herbert

> For example:
> "Microcontrollers, Basics"; "Microcontrollers, Advanced"; and "Hands-On 
> Analysis of Five MCU Development Kits" at
> 

> "ARM Cortex-M0" at 
> 

> "How to Choose a Microcontroller Architecture" at 
> 
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Re: [time-nuts] Follow-up question re: microcontroller families

[Herbert Poetzl]

On Sun, May 26, 2013 at 07:46:38AM -0400, Bob Camp wrote:
> Hi

> On May 25, 2013, at 11:26 PM, Herbert Poetzl  wrote:

>> On Sat, May 25, 2013 at 09:26:02PM -0400, Bob Camp wrote:
>>> Hi

>>> I realize this is a bit like water torture - sorry about that.

>>> If I go to Microchip Direct and ask for a PIC 18F with two
>>> UARTS and two A/D's I get the PIC18F86J72 and PIC 18F87J72.
>>> To me the second one is the obvious winner. It's got twice
>>> the flash for next to nothing more money. 1-25 piece price is
>>> $6.04.

>>> Same search, 1 A/D, 4 UARTS, lowest cost this time. PIC18F65J94
>>> is the winner. Lowest price package is $3.30 in 1-25 pieces.

>> 4 UARTS are untypical for PICs and result in higher price
>> as the device usually has more pins (which makes them more
>> expensive)

> The ARM that the thread was looking at was a 6 UART / 4 A/D
> part. Thus the "load up the UARTS". Also the starting point 
> for all this did involve serial i/o.

I have no idea for what 'home' project you would make
good use of 6 UARTs, but please don't get me wrong,
I'm using a lot of ARM/MIPS microcontrollers and
devices here, and I appreciate that they got really
cheap over the years.

But for many applications, the inevitable overhead
(power, heat, external components, OS, etc) simply 
eliminates the gain of having a better/faster CPU.

Sometimes I end up using a 6 or 8 pin PIC with only
a few lines of code to to solve complex problems where
a (F)PGA/CPLD design would be a lot of work and a 
16/32bit microcontroller simply overkill.

As always, YMMV, best,
Herbert

>>> Are those some *very* arbitrary choices - you bet they are.
>>> They are random picks, and were not optimized to show any
>>> particular thing. Only to target an application that had some
>>> serial i/o and a bit of A/D involvement.

>>> Bottom line - not all PIC's are $1. once you start adding
>>> peripherals. For $6 over in ARM land, you can get a lot of
>>> chip. To be fair, my experience has been that you can do better
>>> in the PIC24 line once you start adding stuff. Searching the
>>> PIC24's is hard enough that my brief search tonight did not
>>> show up a lower cost part.

>> PIC24F04KA200 1 UART, 10 ADC, XLP, 1.38 USD (1.05 USD @1k)
>> PIC24EP32GP202 2 UART, 6 ADC, 2.76 USD (1.86 USD @1k)

> I knew they had to be there. Again suggesting that the PIC24's probably are a 
> better starting point these days.


>> One (dis)advantage of the Microchip PICs is that there
>> are so many different families and parts.

> Indeed

> Bob


>> best,
>> Herbert

>>> Bob

>>> On May 25, 2013, at 9:05 PM, Bob Camp  wrote:

>>>> Hi

>>>> I just realized the "buy direct" button on that page requires a login. The 
>>>> single piece direct price is $9.70. First price break is at 25 pieces (to 
>>>> $8.95).

>>>> Bob

>>>> On May 25, 2013, at 8:56 PM, Bob Camp  wrote:

>>>>> Hi

>>>>> It's one of the Freescale K60's they have them in several speeds and 
>>>>> packages. Others have similar parts.

>>>>> http://www.freescale.com/webapp/sps/site/prod_summary.jsp?code=K60_120&nodeId=01624698C9DE2DDDAF&tab=Buy_Parametric_Tab&fromSearch=false

>>>>> hopefully shows the family information

>>>>> The first part on the list is the MK60FN1M0VLQ12 for 8% more money you 
>>>>> can get the 150 MHz core rather than the 120 MHz core version. Both have 
>>>>> enough pins that you can get at a lot of the peripherals at once. Both 
>>>>> have enough pins that they are not a lot of fun to solder by hand. Of 
>>>>> course their BGA cousins are even less hand solder friendly….

>>>>> Bob


>>>>> On May 25, 2013, at 6:48 PM, Graham / KE9H  wrote:

>>>>>> On 5/25/2013 3:40 PM, Bob Camp wrote:
>>>>>>> You can get a part with 1MB of flash, 128KB of ram, 6 UARTS, 4 16 bit 
>>>>>>> A/D's, 10/100 Ethernet, USB, and a bunch of other stuff for less than 
>>>>>>> $10. Drop this and that, go to half the flash, and yup, the price is 
>>>>>>> 1/2. Comes with a free toolchain and two very capable free versions of 
>>>>>>> RTOS.


>>>>>> Bob:

>>>>>> I was wondering which manufacturer/part you were referring to.

>>>>>> Thanks,
>>>>>> --- Graham

>>>>>> ==

>>>>> 

Re: [time-nuts] Good (cheap) PIC chip choice for project?

[Herbert Poetzl]

On Sun, May 26, 2013 at 07:48:08AM -0400, Bob Camp wrote:
> Hi

> At least with the newer versions ( the X stuff), they 
> really seem to want to see the PIC Kit 3.

As I said, it's a marketing move: the PICkit 2 was
declared obsolete after the main developer left
Microchip and the PICkit 3 was marketed as an
'improved' version, and all new software was geared
toward the 'new' PICkit 3, despite the fact that
it is inferior to the PICkit 2 in almost all regards

Recent updates to the PICkit 3 made it more and more
compatible with the PICkit 2 but it is still missing
certain features like the uart or logic analyzer.

Just google for a comparison (PICkit 2 vs PICkit 3)
to get an idea :)

Best,
Herbert

> Bob

> On May 25, 2013, at 10:20 PM, Herbert Poetzl  wrote:

>> On Sat, May 25, 2013 at 10:04:59PM -0400, Bob Camp wrote:
>>> Hi

>>> If you are putting money into a Microchip programmer, I'd
>>> probably head over to the PIC Kit 3 rather than the 2. It will
>>> do debug as well as programming on the range of parts. 

>> Unfortunately the command line support is missing in the
>> PICkit 3, although there was/is an efford to make the 'new'
>> PICkit 3 compatible with the PICkit 2.
>> (as usualy, marketing decisions ... :)

>> And the PICkit 2 can do all the debugging the PICkit 3
>> does plus it can work as UART and Logic Analyzer as well.

>>> Having breakpoints and debug is a *good* thing.

>> Depends, using breakpoints and/or debug on time critical
>> stuff (like software PWM or UART) usually results in
>> unexpected results, more often it is simpler to add one
>> or more LEDs to display a state or do 'printf' style
>> debugging via serial (UART/I2C/SPI).

>> But as always, YMMV.

>> best,
>> Herbert

>>> Bob

>>> On May 25, 2013, at 9:44 PM, Herbert Poetzl  wrote:

>>>> On Sat, May 25, 2013 at 08:46:03AM -0500, Jason Rabel wrote:
>>>>> I've decided I finally want to tackle learning how to use a PIC
>>>>> chip for some smaller projects. Can someone recommend me a good
>>>>> (and cheap) PIC, and possible some literature (be it a book or
>>>>> website)? I have a fairly recent willem eprom programmer that
>>>>> I'm hoping I can use.

>>>> Microchip has good product selection tools like this one:
>>>> http://www.microchip.com/maps/microcontroller.aspx
>>>> (note the plus signs on the right side of each section)

>>>>> I don't know what all the features PICs have, but for my first
>>>>> project I would like to have it connected to a serial port on
>>>>> one of my Soekris' where it can grab info (i.e. the current
>>>>> time, or NTP/GPS info) and output that on a little LED display.

>>>> Depending on the type of LED display you have in mind, you
>>>> want to have PWM capabilities (multiplexing) and high
>>>> current source/sink, as well as an (E)U(S)ART for the serial
>>>> communication.

>>>> A four digit LED display can be easily controlled by a
>>>> PIC16F1503 (price about 0.8 USD, 14 pins) and the required
>>>> documents are available on the Microchip site:
>>>> http://www.microchip.com/wwwproducts/Devices.aspx?dDocName=en553475

>>>> You can do the UART part in software for low data rates
>>>> or simply take the PIC16F1508/9 which already includes 
>>>> an EUSART (price about 1.3 USD, 20 pins)

>>>> One programmer for many PIC chips (8 bit to 32 bit) is
>>>> the PICkit2 which can be bought for less than 30 USD
>>>> (via usb, works fine on Linux and MacOS as well)

>>>> HTH,
>>>> Herbert

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Re: [time-nuts] Follow-up question re: microcontroller families

[Herbert Poetzl]

On Sat, May 25, 2013 at 09:26:02PM -0400, Bob Camp wrote:
> Hi

> I realize this is a bit like water torture - sorry about that.

> If I go to Microchip Direct and ask for a PIC 18F with two
> UARTS and two A/D's I get the PIC18F86J72 and PIC 18F87J72.
> To me the second one is the obvious winner. It's got twice
> the flash for next to nothing more money. 1-25 piece price is
> $6.04.

> Same search, 1 A/D, 4 UARTS, lowest cost this time. PIC18F65J94
> is the winner. Lowest price package is $3.30 in 1-25 pieces.

4 UARTS are untypical for PICs and result in higher price
as the device usually has more pins (which makes them more
expensive)

> Are those some *very* arbitrary choices - you bet they are.
> They are random picks, and were not optimized to show any
> particular thing. Only to target an application that had some
> serial i/o and a bit of A/D involvement.

> Bottom line - not all PIC's are $1. once you start adding
> peripherals. For $6 over in ARM land, you can get a lot of
> chip. To be fair, my experience has been that you can do better
> in the PIC24 line once you start adding stuff. Searching the
> PIC24's is hard enough that my brief search tonight did not
> show up a lower cost part.

PIC24F04KA200 1 UART, 10 ADC, XLP, 1.38 USD (1.05 USD @1k)
PIC24EP32GP202 2 UART, 6 ADC, 2.76 USD (1.86 USD @1k)

One (dis)advantage of the Microchip PICs is that there
are so many different families and parts.

best,
Herbert

> Bob

> On May 25, 2013, at 9:05 PM, Bob Camp  wrote:

>> Hi

>> I just realized the "buy direct" button on that page requires a login. The 
>> single piece direct price is $9.70. First price break is at 25 pieces (to 
>> $8.95).

>> Bob

>> On May 25, 2013, at 8:56 PM, Bob Camp  wrote:

>>> Hi

>>> It's one of the Freescale K60's they have them in several speeds and 
>>> packages. Others have similar parts.

>>> http://www.freescale.com/webapp/sps/site/prod_summary.jsp?code=K60_120&nodeId=01624698C9DE2DDDAF&tab=Buy_Parametric_Tab&fromSearch=false

>>> hopefully shows the family information

>>> The first part on the list is the MK60FN1M0VLQ12 for 8% more money you can 
>>> get the 150 MHz core rather than the 120 MHz core version. Both have enough 
>>> pins that you can get at a lot of the peripherals at once. Both have enough 
>>> pins that they are not a lot of fun to solder by hand. Of course their BGA 
>>> cousins are even less hand solder friendly….

>>> Bob


>>> On May 25, 2013, at 6:48 PM, Graham / KE9H  wrote:

 On 5/25/2013 3:40 PM, Bob Camp wrote:
> You can get a part with 1MB of flash, 128KB of ram, 6 UARTS, 4 16 bit 
> A/D's, 10/100 Ethernet, USB, and a bunch of other stuff for less than 
> $10. Drop this and that, go to half the flash, and yup, the price is 1/2. 
> Comes with a free toolchain and two very capable free versions of RTOS.


 Bob:

 I was wondering which manufacturer/part you were referring to.

 Thanks,
 --- Graham

 ==

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Re: [time-nuts] Good (cheap) PIC chip choice for project?

[Herbert Poetzl]

On Sat, May 25, 2013 at 10:04:59PM -0400, Bob Camp wrote:
> Hi

> If you are putting money into a Microchip programmer, I'd
> probably head over to the PIC Kit 3 rather than the 2. It will
> do debug as well as programming on the range of parts. 

Unfortunately the command line support is missing in the
PICkit 3, although there was/is an efford to make the 'new'
PICkit 3 compatible with the PICkit 2.
(as usualy, marketing decisions ... :)

And the PICkit 2 can do all the debugging the PICkit 3
does plus it can work as UART and Logic Analyzer as well.

> Having breakpoints and debug is a *good* thing.

Depends, using breakpoints and/or debug on time critical
stuff (like software PWM or UART) usually results in
unexpected results, more often it is simpler to add one
or more LEDs to display a state or do 'printf' style
debugging via serial (UART/I2C/SPI).

But as always, YMMV.

best,
Herbert

> Bob

> On May 25, 2013, at 9:44 PM, Herbert Poetzl  wrote:

>> On Sat, May 25, 2013 at 08:46:03AM -0500, Jason Rabel wrote:
>>> I've decided I finally want to tackle learning how to use a PIC
>>> chip for some smaller projects. Can someone recommend me a good
>>> (and cheap) PIC, and possible some literature (be it a book or
>>> website)? I have a fairly recent willem eprom programmer that
>>> I'm hoping I can use.

>> Microchip has good product selection tools like this one:
>> http://www.microchip.com/maps/microcontroller.aspx
>> (note the plus signs on the right side of each section)

>>> I don't know what all the features PICs have, but for my first
>>> project I would like to have it connected to a serial port on
>>> one of my Soekris' where it can grab info (i.e. the current
>>> time, or NTP/GPS info) and output that on a little LED display.

>> Depending on the type of LED display you have in mind, you
>> want to have PWM capabilities (multiplexing) and high
>> current source/sink, as well as an (E)U(S)ART for the serial
>> communication.

>> A four digit LED display can be easily controlled by a
>> PIC16F1503 (price about 0.8 USD, 14 pins) and the required
>> documents are available on the Microchip site:
>> http://www.microchip.com/wwwproducts/Devices.aspx?dDocName=en553475

>> You can do the UART part in software for low data rates
>> or simply take the PIC16F1508/9 which already includes 
>> an EUSART (price about 1.3 USD, 20 pins)

>> One programmer for many PIC chips (8 bit to 32 bit) is
>> the PICkit2 which can be bought for less than 30 USD
>> (via usb, works fine on Linux and MacOS as well)

>> HTH,
>> Herbert

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Re: [time-nuts] Good (cheap) PIC chip choice for project?

[Herbert Poetzl]

On Sat, May 25, 2013 at 08:46:03AM -0500, Jason Rabel wrote:
> I've decided I finally want to tackle learning how to use a PIC
> chip for some smaller projects. Can someone recommend me a good
> (and cheap) PIC, and possible some literature (be it a book or
> website)? I have a fairly recent willem eprom programmer that
> I'm hoping I can use.

Microchip has good product selection tools like this one:
http://www.microchip.com/maps/microcontroller.aspx
(note the plus signs on the right side of each section)

> I don't know what all the features PICs have, but for my first
> project I would like to have it connected to a serial port on
> one of my Soekris' where it can grab info (i.e. the current
> time, or NTP/GPS info) and output that on a little LED display.

Depending on the type of LED display you have in mind, you
want to have PWM capabilities (multiplexing) and high
current source/sink, as well as an (E)U(S)ART for the serial
communication.

A four digit LED display can be easily controlled by a
PIC16F1503 (price about 0.8 USD, 14 pins) and the required
documents are available on the Microchip site:
http://www.microchip.com/wwwproducts/Devices.aspx?dDocName=en553475

You can do the UART part in software for low data rates
or simply take the PIC16F1508/9 which already includes 
an EUSART (price about 1.3 USD, 20 pins)

One programmer for many PIC chips (8 bit to 32 bit) is
the PICkit2 which can be bought for less than 30 USD
(via usb, works fine on Linux and MacOS as well)

HTH,
Herbert

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Re: [time-nuts] Good (cheap) PIC chip choice for project?

[Herbert Poetzl]

On Sat, May 25, 2013 at 04:03:36PM -0700, Chris Albertson wrote:
> In general PICs need assembly language for many things.
> AVRs almost never need assembly. 

I've done quite a number of PIC projects, from low end
8 bit up to the high end 32 bit controllers, and except
for a really time critical software PWM solution I never
had to write in assembler (although I'm quite comfortable
with assembler code :)

> The reason is that the AVR designers studied C compilers
> and made the AVR an easy compiler target.

> A compiler writer like to have an "orthogonal" instruction 
> set and some other features. So the AVR compirrs generate 
> very good code and there is little reason to resort to 
> assembly

Recent PIC toolchains use gcc which allows for inline
assembly and provides a reasonable set of builtin 
instructions to allow for handling almost everything
within C.

The compiler does a good job, and there are proprietary
compilers available if you need to achieve really high
optimization (size or speed wise)

best,
Herbert

> On Sat, May 25, 2013 at 2:24 PM, Rex  wrote:
>> On 5/25/2013 1:22 PM, Bob Camp wrote:

>>> If you are going to code on a cheap PIC (the PIC16 series)
>>> you will likely need to learn PIC assembler. All my coding
>>> on those parts was in assembly language. They are old enough
>>> / slow enough / small RAM enough that things like C (or the
>>> other high level languages you listed) really don't do well
>>> on them.

>> Several years back I did a bunch of stuff with various PIC16
>> series chips. All of it, except for some minor assembler
>> tweaks, was done in C. Glad I did not know it wasn't
>> practical. I would have wasted a lot of time coding it in
>> assembler. Of course my goal was just getting something done,
>> not being elegant or very efficient. Time-nutty stuff like
>> TVB's frequency divider may require the detail and efficiency
>> only provided by assembler.

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> -- 

> Chris Albertson
> Redondo Beach, California
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Re: [time-nuts] RPi NTP was Net4501's cheap...

[Herbert Poetzl]

On Sat, May 25, 2013 at 05:06:57PM +, li...@lazygranch.com wrote:
> Flightradar24 is using beagle bones in their ADS-B/mode-s
> system and will be incorporating MLAT soon. I suspect they work
> well in timing applications.

> That said, the Allwinner they sell on Sparkfun will probably be
> my next SBC. Though not listed on the wiki, they have opensuse
> running on it.

> BTW, on some linux dists, there is a way to get around the
> clock speed stepping. It may not be universal, but selecting
> "performance" works on opensuse for Arm.

The speed stepping (and similar performance control mechanisms)
are managed by so called 'governors' which are part of the
kernel, and thus do not really depend on the distro.

they can be loaded (as modules) or compiled into the kernel
and they can be controlled via userspace tools or via the
sysfs entries.

HTH,
Herbert

> -Original Message-
> From: Paul 
> Sender: time-nuts-boun...@febo.com
> Date: Sat, 25 May 2013 12:47:38 
> To: 
> Reply-To: Discussion of precise time and frequency measurement
>   
> Subject: [time-nuts] RPi NTP was Net4501's cheap...

> On Sat, May 25, 2013 at 2:43 AM, David J Taylor wrote:

>>  Paul,

>> Just what devices were you hot-plugging to produce this
>> problem? One with an initial current surge outside the USB
>> spec I could understand.

> I was plugging in a USB to RS232 adapter. If you read the
> various bits you'll find about the USB on Rev.B boards
> you'll see all the work-arounds suggested here as well as an
> implication that Raspberry intends to fix the problem in a
> later release.

>> NTP performance on the three Raspberry Pi cards here can be of
>> the same order as FreeBSD running on an Intel Atom PC:

> Yes, I've looked at your stats. As I said earlier you put me
> onto the Pi and the Sure boards. The offsets on the Pi are
> fine. I just don't like the "weak" network performance which
> you can see in the ntpq output for the Pi. Since I'm still
> testing bits all four of my clocks are on the same gigabit
> switch so I don't expect to see simultaneous negative and
> positive offsets. The Laureline is jittery too but at least it
> always presents the same offset "polarity". I'll see how the
> Beaglebones do, check out the next rev. of the Laureline and
> then dither some more.
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Re: [time-nuts] time transfer over USB

[Herbert Poetzl]

On Tue, May 14, 2013 at 08:10:38PM -0700, Peter Monta wrote:
>>> Bulk transfer might work well on a system where nothing else is going
>>  on,
>>> so "best effort" translates to "now".

>> Does it mean "now" or "next polling cycle"?


> It means "now", or pretty close. No waiting for
> start-of-USB-frame or -microframe.

> Herbert mentions that all USB transfers are host-initiated,
> which is true (even for the so-called "interrupt" transfers),
> but the latency is usually much less than one frame on a
> lightly loaded bus I believe.

http://www.beyondlogic.org/usbnutshell/usb4.shtml

best,
Herbert

> I agree with Magnus' remark that this is not rocket science.
> Maybe it's time for a small proof of principle, using something
> like a Teensy board, that takes PPS edges from the outside
> world and connects them to USB.

> GNSS samplers should be timestamping their packets so that the
> relationship between sample number and device-local time (and
> ultimately also host time) can be known.

> Cheers,
> Peter
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Re: [time-nuts] time transfer over USB

[Herbert Poetzl]

On Tue, May 14, 2013 at 03:11:58PM -0700, Hal Murray wrote:

> jim...@earthlink.net said:
>> Bulk transfer might work well on a system where nothing else
>> is going on, so "best effort" translates to "now".

> Does it mean "now" or "next polling cycle"?

It's always 'next polling cycle' because all USB
transfers are initiated by the host, and the client
'just' replies with e.g. data.

Personally I do not see how Bulk Transfers would
be better than Interrupt or Isochronous Transfers
because they will have a lower priority an the
same minimum interval, so no advantage over the
other transfer modes.

best,
Herbert

> -- 
> These are my opinions.  I hate spam.

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Re: [time-nuts] time transfer over USB

[Herbert Poetzl]

On Tue, May 14, 2013 at 12:40:01AM -0700, Peter Monta wrote:

>> IMHO the transfer mode of choice for this purpose should
>> be the Isochronous Transfer (in USB 2.0 and 3.0) because
>> it happens periodically and thus can achieve a guaranteed
>> maximum latency (for high speed this means 125us).

> If 1 ms or 125 us is good enough, then this would be fine;
> but for better precision there seem to be two problems with
> isochronous transfers: you don't know when the USB frame
> starts, and you don't know where you are in the pecking order
> of subscribers to the isochronous subset of the USB bandwidth.

> The first one could be overcome by doing many timestamp
> exchanges at random times, then seeing which times modulo 
> 1 ms or 125 us are quickest. 

> But the second one seems more difficult and could change
> unpredictably over time.

You can easily assure that you are the only subscriber.

> The nice thing about bulk transfers is that they're 
> best-effort and don't come burdened with any fancy USB 
> scheduler stuff.

> So a USB-based GPS should:

> - maintain a cycle count of its local crystal oscillator 
>   (e.g. with a timer peripheral)
> - report this count when requested
> - timestamp PPS edges from the GPS module, and report these 
>   timestamps when requested

> This would seem to be enough to gradually converge to a 
> good estimate of (USB_host_time - GPS_PPS) across the 
> noisy USB link.

I thought the plan was to transfer the PPS via USB without
additional hardware, of course, with external timestamping
the actual usb transfer doesn't matter much if you do it
properly (and over time that is)

best,
Herbert

> Cheers,
> Peter
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Re: [time-nuts] time transfer over USB

[Herbert Poetzl]

On Mon, May 13, 2013 at 08:36:14PM -0700, Peter Monta wrote:
> I wonder if the following scheme would work to improve
> measurement precision over USB for use with GPS devices 
> or similar.

> Instead of USB interrupt transfers, which occur on 1 ms
> boundaries with some unknown epoch, use bulk transfers. 
> In the good case, there are no other USB transactions in
> flight, the request goes out immediately, the device 
> responds immediately, and the entire link has the lowest 
> latency possible. 

IMHO the transfer mode of choice for this purpose should 
be the Isochronous Transfer (in USB 2.0 and 3.0) because
it happens periodically and thus can achieve a guaranteed
maximum latency (for high speed this means 125us).

> If these conditions don't hold, the completion time will be
> delayed. Now use robust estimation techniques to get rid
> of these exceptions and instead follow the smooth line of
> best-case responses. NTP implementations do something like 
> this already, but at longer timescales, and targeted at
> Internet links rather than a single local USB link.

> If the best-case response time is calibrated out, how good 
> can this get? Microseconds?

With 125us latency and a fixed interval, it should be
possible to calculate the relation between the transfer
intervall (USB clock crystal) and the PPS (or whatever 
information is transmitted) and thus easily get below 
the 100us.

best,
Herbert

> Cheers,
> Peter
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Re: [time-nuts] APN-9A Very Rare LORAN-A Manual Copies Available

[Herbert Poetzl]

On Sun, Apr 21, 2013 at 11:21:33AM -0700, J. Forster wrote:
> As you may know, some time ago, I acquired an all-but-mythical
> APN-9A LORAN-A receiver/Indicator.

> This is not the common APN-9 LORAN-A, but is a hybrid
> (analog/digital) version built for the B-36 bomber. 
> Very few were built and documentation is just about
> non-existant.

> I have been very generously lent a copy of the Handbook of
> Operating Instructions (AN 16-30APN9-6) and the Handbook
> of Maintenance Instructions (AN 16-30APN9-7) plus some
> manuals on the Antenna Couplers. This is very likely the 
> only documentation extant on the set.

> I am going to make a high quality Xerox copy of the manual,
> but, since it is little extra effort to make additional 
> copies at the same time, I'm willing to make additional 
> copies at Staples cost + postage.

> Note:

> This is a one time only offer. It has to be manually fed.
> I do not own the original.
> I am offering anything but Xeroxs of the original.
> The copies will be two-sidede, like the original.
> Oversized sheets will be copied in one piece, oversized.
> I'd expect the copying cost to be under $50.
> Only the complete manuals are available.

Just out of curiosity: wouldn't it be way smarter to 
make high resolution Scans instead of Copies, to preserve 
the Information for posterity?

best,
Herbert

PS: no, I'm not interested in a copy _or_ scan.

> If you are interested, please contact me off-list ONLY, 
> before next Saturday.

> Best,

> -John

> =






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Re: [time-nuts] AD5791 for EFC control ?

[Herbert Poetzl]

On Sat, Apr 20, 2013 at 08:14:06PM +, Poul-Henning Kamp wrote:

> I looked at the DAC1220 first, but in an EFC application it
> worries me to no end that it is a Sigma-Delta DAC.

> Even if I feed it a clock divided down from the OCXO you're
> EFC'ing, to avoid beatfrequency effects, I would still worry
> about harmonic effects and noise.

> Also, the noise-spec is pretty horrid, almost a
> microvolt/sqrt(Hz) all the way to one kHz.

> For comparison the AD5791 is purely static and its noise is
> below 10 nv/sqrt(Hz) from 5Hz and up.

At a price of ~100 USD (100pcs for ~50 USD each) 
it's also in a different price range as the DAC1220
which can be bought for less than 20 USD (~8 USD
when you buy 100).

best,
Herbert

> -- 
> Poul-Henning Kamp   | UNIX since Zilog Zeus 3.20
> p...@freebsd.org | TCP/IP since RFC 956
> FreeBSD committer   | BSD since 4.3-tahoe
> Never attribute to malice what can adequately be explained by incompetence.
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Re: [time-nuts] AD5791 for EFC control ?

[Herbert Poetzl]

On Fri, Apr 19, 2013 at 09:20:05AM -0400, ewkeh...@aol.com wrote:
> As one of our digital loop projects we took a very, very close 
> look at it, but thought once you consider the application, 
> requirements of external references, its influence on  
> temperature performance and cost, a dithered 20 bit LTC 1655   
> held at 0.1 C is as good a solution. 

Texas Instruments has a number of precision DACs for a
very reasonable price, for example the DAC1220 (20bit
low power delta-sigma, ~8 USD) and precision voltage
references to go with (e.g. REF5050, ~2 USD).

best,
Herbert

> Have not actually tested a 5791 but I know some one that has   
> an evaluation board. 

> I will ask him to contact you off list 

> Bert Kehren


> In a message dated 4/19/2013 7:22:16 A.M. Eastern Daylight Time,  
> p...@phk.freebsd.dk writes:


> Has  anybody tried using the AD5791 20bit DAC for EFC control ?

> --  
> Poul-Henning Kamp   | UNIX since Zilog Zeus  3.20
> p...@freebsd.org | TCP/IP since RFC  956
> FreeBSD committer   | BSD since  4.3-tahoe
> Never attribute to malice what can adequately be explained by  incompetence.
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Re: [time-nuts] Z3805A flash dump.

[Herbert Poetzl]

On Wed, Apr 17, 2013 at 03:38:56PM +, Mark C. Stephens wrote:
> It is possible I didn't take the dump correctly, 
> or there is a problem with my burner. 

> I chose Binary when saving files.

That's always a good choice :)

> Perhaps, the other possibility is those flash chips 
> aren't the actual firmware, just storage.

> The actual firmware (program) flash chip could be 
> located elsewhere. 

Unlikely, otherwise I would not have been able to
reconstruct the (maybe?) partial data from your dumps.
(see the files I linked in the previous reply)

> However, that would seem a bit strange to me, why 
> socket transient memory and not the actual program 
> itself?

> How should I have taken the flash dumps?

I do not even know what ROM/Flash? chips are used
in this device, but from your reply I conclude that
they are socketed and you were able to read them
via some kind of EEPROM reader/burner?

If so, given that the 'reader' supports the chips
in question, I'd say your dumps are probably fine.

A good method is to dump each chip several times
(if possible in different ways) and compare the
results.

Assuming that everything was dumped correctly, it
might simply be that the device uses only a small 
portion of the ROM/Flash for PSOS (operating system)
and the rest for data storage or checksumming.

A schematic how the chips connect to the CPU might
sched some light on the data stored/used as might
more information about the involved components.

best,
Herbert

> -mark



> -Original Message-
> From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On 
> Behalf Of Herbert Poetzl
> Sent: Thursday, 18 April 2013 12:43 AM
> To: Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] Z3805A flash dump.

> On Wed, Apr 17, 2013 at 08:31:49AM +, Mark C. Stephens wrote:
>> I have dumped the 4 flash ROMS from my latest Z3805A but I can't make 
>> head nor tail of the contents.

>> I am thinking the flash are interleaved.

> Interleaving makes sense for performance reasons and usually
> happens at bit or byte level, but I'm not (yet) convinced that
> the data was dumped correctly.

>> http://www.vk2hmc.net/blog/wp-content/uploads/2013/04/z3805-flash.rar

> Assuming that the Z3801A and Z3805A ROM contents is somewhat similar (1x512k 
> = 4x128k), let's take a look at the entropy of the data:

> $ cat z3801a.bin | xz --stdout | wc -c
>   110020

> $ cat z3805-*.bin | xz --stdout | wc -c
>60436

> This rough estimate on the amount of non redundant data shows that the z3801a 
> ROM contains almost twice as much data than the z3805 ROM dumps together.

> $ for n in z3805-*.bin; do xz --stdout $n | wc -c; done
>25108
>30724
>24712
>22812

> This shows that the data is almost evenly distribute between the four dumps, 
> so some kind of interleaving is obviously present and none of the files are 
> purely random or contain just padding or similar like:

> $ dd if=/dev/urandom bs=1k count=128 | xz --stdout | wc -c
>   131140
> $ dd if=/dev/zero bs=1k count=128 | xz --stdout | wc -c
>  152

> Now looking at the data itself, it is simple to see that there is a 
> positional redundancy present:

> $ for n in z3805-*.bin; do xxd -g 1 $n | head -1; done
> 000: 6f ff 00 05 04 05 00 05 10 05 00 05 28 05 00 05  o...(...
> 000: 6f 10 00 05 04 fe 00 05 10 00 00 05 28 50 00 05  o...(P..
> 000: 6f a0 00 05 04 00 00 05 10 42 00 05 28 42 00 05  oB..(B..
> 000: 6f 00 00 05 04 ff 00 05 10 00 00 05 28 05 00 05  o...(...

> Columns 1, 3, 4, 5, 7, 8, 9 ... are all equal, only the columns 2, 6, 10, 14 
> ... contain different values across the files, which basically means that 3 
> out of
> 4 bytes are completely identical between the 4 dumps.
> (this is, where I think something might have gone wrong with the dumps :)

> Anyway, extracting the data from the columns where the dumps actually differ 
> gives the following data [1]:

> $ xxd col.data | head -4
> 000: ff10 a000 05fe 00ff 0500 4200 0550 4205  ..B..PB.
> 010: 0510  05b4 1105 0510  05b4 0005  
> 020: 0510 1100 05b4 0005 0510  05b4 1105  
> 030: 1310  05b4 0005 0510 1100 05b4 0005  

> Comparing this with the dump from z3801a ROM:

> $ xxd z3801a.bin | head -4
> 000: 0010 fffe  0550 0010 05b4 0010 05b4  ...P
> 010: 0010 05b4 0010 05b4 0010 05b4 0010 05b4  
> 020: 0010 05b4 0010 05b4 0010 05b4 0010 05b4  
> 030: 0010 05b4 0010 05b4 0010 05b4 0010 05b4  

> Suggests that there is some kind of reordering required to get the 

Re: [time-nuts] Z3805A flash dump.

[Herbert Poetzl]

On Wed, Apr 17, 2013 at 08:31:49AM +, Mark C. Stephens wrote:
> I have dumped the 4 flash ROMS from my latest Z3805A but 
> I can't make head nor tail of the contents. 

> I am thinking the flash are interleaved.

Interleaving makes sense for performance reasons and
usually happens at bit or byte level, but I'm not (yet)
convinced that the data was dumped correctly.

> http://www.vk2hmc.net/blog/wp-content/uploads/2013/04/z3805-flash.rar

Assuming that the Z3801A and Z3805A ROM contents is
somewhat similar (1x512k = 4x128k), let's take a look
at the entropy of the data:

$ cat z3801a.bin | xz --stdout | wc -c
  110020

$ cat z3805-*.bin | xz --stdout | wc -c
   60436

This rough estimate on the amount of non redundant
data shows that the z3801a ROM contains almost twice
as much data than the z3805 ROM dumps together.

$ for n in z3805-*.bin; do xz --stdout $n | wc -c; done
   25108
   30724
   24712
   22812

This shows that the data is almost evenly distribute
between the four dumps, so some kind of interleaving
is obviously present and none of the files are purely
random or contain just padding or similar like:

$ dd if=/dev/urandom bs=1k count=128 | xz --stdout | wc -c
  131140
$ dd if=/dev/zero bs=1k count=128 | xz --stdout | wc -c
 152

Now looking at the data itself, it is simple to see
that there is a positional redundancy present:

$ for n in z3805-*.bin; do xxd -g 1 $n | head -1; done
000: 6f ff 00 05 04 05 00 05 10 05 00 05 28 05 00 05  o...(...
000: 6f 10 00 05 04 fe 00 05 10 00 00 05 28 50 00 05  o...(P..
000: 6f a0 00 05 04 00 00 05 10 42 00 05 28 42 00 05  oB..(B..
000: 6f 00 00 05 04 ff 00 05 10 00 00 05 28 05 00 05  o...(...

Columns 1, 3, 4, 5, 7, 8, 9 ... are all equal, only
the columns 2, 6, 10, 14 ... contain different values
across the files, which basically means that 3 out of
4 bytes are completely identical between the 4 dumps.
(this is, where I think something might have gone
wrong with the dumps :)

Anyway, extracting the data from the columns where the
dumps actually differ gives the following data [1]:

$ xxd col.data | head -4
000: ff10 a000 05fe 00ff 0500 4200 0550 4205  ..B..PB.
010: 0510  05b4 1105 0510  05b4 0005  
020: 0510 1100 05b4 0005 0510  05b4 1105  
030: 1310  05b4 0005 0510 1100 05b4 0005  

Comparing this with the dump from z3801a ROM:

$ xxd z3801a.bin | head -4
000: 0010 fffe  0550 0010 05b4 0010 05b4  ...P
010: 0010 05b4 0010 05b4 0010 05b4 0010 05b4  
020: 0010 05b4 0010 05b4 0010 05b4 0010 05b4  
030: 0010 05b4 0010 05b4 0010 05b4 0010 05b4  

Suggests that there is some kind of reordering required
to get the similar structure present in the hardware
vector table.

The following mapping seems to do the trick:
Pick every odd byte from the data and switch every
two resulting bytes, or as pseudocode:

for (n = 0; n < 2; n++) {
for (i = 0; i < dlen; i += 4) {
j = i/2;

split[n][j + 0] = data[i + n + 2];
split[n][j + 1] = data[i + n + 0];
}
}

The resulting data [2] seems to contain meaningful 
strings and binary code similar to the z3801a ROM:

$ strings split.data | grep psos
>@(#)$Header: psos.S,v 1.4 95/01/11 15:27:21 jacob Exp $
@(#)$Header: psos_indep.h,v 1.5 95/03/24 15:24:19 da oe uxn d
>@(#)$Header: psos.S,v 1.4 95/01/11 15:27:21 jacob Exp $
@(#)$Header: psos_indep.h,v 1.5 95/03/24 15:24:19 da oe uxn d

HTH,
Herbert

[1] http://vserver.13thfloor.at/Stuff/VARIOUS/Z3805/col1.data
[2] http://vserver.13thfloor.at/Stuff/VARIOUS/Z3805/split1.data

> I can't see any strings that make sense like the Z3801A flash.


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Re: [time-nuts] Changing FE-5650A frequency?

[Herbert Poetzl]

On Sun, Apr 07, 2013 at 11:27:23AM +0100, Alexander Wright wrote:
> On 07/04/13 05:01, WB6BNQ wrote:
>> Hi Alec,

>> You may be in luck.  However, I would need some additional pictures, 
>> particularly
>> of the connector on the bottom, also some of the inside.


> Bill,

> Thanks for your reply! Here are some photos of the inside: 
> http://m0tei.co.uk/fe5650pics/

> You'll see that it comes with a custom machined plate screwed
> onto the front - this was how it was mounted in the thing i
> pulled it out of. It can be removed but i found it easier to
> take the thing apart with it on. A thermostatic switch used to
> bolt onto it to (presumably) act as a thermal cutout.

The baseplate (2xLM2941, LP2952) basically is the power
supply/regulation, so nothing interesting there.

> You'll also notice that the boards we're probably interested
> in are potted it some sort of white compound - it's hard but
> crumbly - feels like some sort of polymer foam. I've started
> to pick it off a bit but could you just confirm that this is
> actually a sensible thing to do before I go all out scraping 
> it off? 

The purpose of the polymer foam is isolation to keep a 
stable temperature throughout the boards.

http://www.qsl.net/z/zl1bpu/PROJ/FE5650-2.jpg

The top layer in this image is the DDS board, and it is
basically identical to the FE5680A, which means it can
be adjusted in a wide range, but only does digital synthesis
based on the reference frequency.

But let's see what Bill says to the pictures ... :)

best,
Herbert

> Thanks!

>> The primary physics package is a stand alone analog Rubidium frequency 
>> standard

>> that outputs 50.255* MHz frequency.  That signal is used to drive various 
>> output
>> board configurations, included inside the unit, to provide a customer 
>> required
>> output frequency.  The more recent revised units (they look the same) use 
>> a new
>> digital scheme that is much more of a hassle.


> This unit is probably from late 1996/1997 if that helps?

>> The one that I and a number of people are familiar with is the 
>> 5650-option-58
>> model whose output was a 1pps.  To get the 1pps the 50.255+ MHz signal was 
>> used
>> to drive a Direct Digital Synthesizer (DDS) that produced 8.3+ MHz signal 
>> that
>> was then divided down via normal TTL dividers to produce the 1pps.  The 
>> DDS is
>> capable of being changed to other frequencies up to about 20 MHz, however, 
>> the
>> filter following the DDS needs to be changed or bypassed to properly 
>> filter the
>> new frequency.  Bypassing is the easiest method but would require using an
>> external filter to get rid of aliasing and spurs.

>> I put together a zip file of various information on FEI-5650-option 58 
>> that will
>> help you get familiar with the family line.  If you have problems with the 
>> link
>> let me know.  Also, after you get a successful download let me know so I 
>> can
>> reduce the FTP storage level, thank you.

>> http://pages.suddenlink.net/stevewingate/cryptic1/for alec on 
>> 5650-option-58.zip

>> BillWB6BNQ


> Awesome, looks like there's some great info there! Unfortunately i'm not 
> sure hoe relevant it is to mine since my option doesn't seem to do RS232


> On 07/04/13 04:17, Herbert Poetzl wrote:

>> Open it up, take some nice pictures of the circuit boards
>> and components and I can probably tell you what might be
>> possible (after looking at them :).


> Thanks Herbert! Pictures above^

>>> As far as i'm aware this model doesn't have serial control.

>> best,
>> Herbert


> Best regards,
> Alec


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Re: [time-nuts] Changing FE-5650A frequency?

[Herbert Poetzl]

On Sun, Apr 07, 2013 at 12:41:10AM +0100, Alexander Wright wrote:
> Hi all,
> I've recently ripped some FE-5650A's out of some old equipment,
> but they seem to be a custom build, here you can see they have
> the option just listed as "-":
> http://cambridge.m0tei.co.uk/files/IMG_20130330_232647.jpg

> They seem to be single rail (15v) supply with an 800kHz output.
> I wonder, does anyone know if it's possible to change its
> frequency? 

Open it up, take some nice pictures of the circuit boards
and components and I can probably tell you what might be
possible (after looking at them :).

> As far as i'm aware this model doesn't have serial control.

best,
Herbert

> Thanks,
> Alec M0TEI
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Re: [time-nuts] Z3805A Port 2.

[Herbert Poetzl]

On Thu, Apr 04, 2013 at 02:54:09PM -0400, Paul wrote:
>1  3  0  9  4  1  4  2  8  4  4  = 1309412844

>>> I can see its transmitting the even second time but what format
>>> is this and how can I use it?

>> $ date +"%s" # unix time (seconds since Jan, 1st, 1970)
>> 1365086814

>> so, my guess is, it is seconds since some point in
>> time in decimal.

> $ date --date=@1309412844
> Thu Jun 30 01:47:24 EDT 2011

yeah, well, I kind of assumed, that Mark didn't wait
twenty months to send the email :)

best,
Herbert

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Re: [time-nuts] Z3805A Port 2.

[Herbert Poetzl]

On Thu, Apr 04, 2013 at 08:28:58AM -0700, Jim Lux wrote:
> On 4/4/13 7:52 AM, Herbert Poetzl wrote:
>> On Thu, Apr 04, 2013 at 02:32:09PM +, Mark C. Stephens wrote:
>>> I wanted to have a look at what the Z3805A puts out on Port 2.

>>> I can see the LEDS flickering on the BOB so its saying something.
>>> I connected up a terminal program set to 96008N1 and it seems there is 
>>> nothing.
>>> So I plugged the cable into port one to check the settings:
>>> scpi > syst:comm:ser2:pace?
>>> NONE
>>> scpi > syst:comm:ser2:baud?
>>> +9600
>>> scpi > syst:comm:ser2:parity?
>>> NONE
>>> scpi > syst:comm:ser2:bits?
>>> +8
>>> scpi > syst:comm:ser2:sbits?
>>> +1
>>> So Serial 2 is definitely 96008N1.

>>> Nothing displays on the terminal program so I used a serial
>>> port monitor program and I see this recurring data:

>>> 01 03 00 09 04 01 04 02 08 02 06 01 06 00 00 0D
>>> 01 03 00 09 04 01 04 02 08 02 08 01 06 00 00 0D
>>> 01 03 00 09 04 01 04 02 08 03 00 01 06 00 00 0D
>>> 01 03 00 09 04 01 04 02 08 03 02 01 06 00 00 0D
>>> 01 03 00 09 04 01 04 02 08 03 04 01 06 00 00 0D
>>> 01 03 00 09 04 01 04 02 08 03 06 01 06 00 00 0D
>>> 01 03 00 09 04 01 04 02 08 03 08 01 06 00 00 0D
>>> 01 03 00 09 04 01 04 02 08 04 00 01 06 00 00 0D
>>> 01 03 00 09 04 01 04 02 08 04 02 01 06 00 00 0D
>>> 01 03 00 09 04 01 04 02 08 04 04 01 06 00 00 0D

>>1  3  0  9  4  1  4  2  8  4  4  = 1309412844

>>> I can see its transmitting the even second time but what format
>>> is this and how can I use it?

>> $ date +"%s" # unix time (seconds since Jan, 1st, 1970)
>> 1365086814

>> so, my guess is, it is seconds since some point in
>> time in decimal.

> perhaps since week 0  (6 Jan 1980)

difference is roughly 55Ms (depending on the time the
sample was taken) which is roughly 1.75 years, so the
start date should be somewhere around October 1971,
which seems a little odd to me ...

but maybe it counts in half seconds since mid 1992, in
which case the increment by two would happen every
second.

GPS time should start at Jan,6th 1980, so that doesn't
really match anything here, OTOH, RTC clocks use decimal
coding as well, so each byte could simply be the current
RTC entry/register ... hard to say without the exact
time when the sample was taken.

best,
Herbert

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Re: [time-nuts] Z3805A Port 2.

[Herbert Poetzl]

On Thu, Apr 04, 2013 at 02:32:09PM +, Mark C. Stephens wrote:
> I wanted to have a look at what the Z3805A puts out on Port 2.

> I can see the LEDS flickering on the BOB so its saying something.
> I connected up a terminal program set to 96008N1 and it seems there is 
> nothing.
> So I plugged the cable into port one to check the settings:
> scpi > syst:comm:ser2:pace?
> NONE
> scpi > syst:comm:ser2:baud?
> +9600
> scpi > syst:comm:ser2:parity?
> NONE
> scpi > syst:comm:ser2:bits?
> +8
> scpi > syst:comm:ser2:sbits?
> +1
> So Serial 2 is definitely 96008N1.

> Nothing displays on the terminal program so I used a serial
> port monitor program and I see this recurring data:

> 01 03 00 09 04 01 04 02 08 02 06 01 06 00 00 0D
> 01 03 00 09 04 01 04 02 08 02 08 01 06 00 00 0D
> 01 03 00 09 04 01 04 02 08 03 00 01 06 00 00 0D
> 01 03 00 09 04 01 04 02 08 03 02 01 06 00 00 0D
> 01 03 00 09 04 01 04 02 08 03 04 01 06 00 00 0D
> 01 03 00 09 04 01 04 02 08 03 06 01 06 00 00 0D
> 01 03 00 09 04 01 04 02 08 03 08 01 06 00 00 0D
> 01 03 00 09 04 01 04 02 08 04 00 01 06 00 00 0D
> 01 03 00 09 04 01 04 02 08 04 02 01 06 00 00 0D
> 01 03 00 09 04 01 04 02 08 04 04 01 06 00 00 0D

   1  3  0  9  4  1  4  2  8  4  4  = 1309412844

> I can see its transmitting the even second time but what format
> is this and how can I use it?

$ date +"%s" # unix time (seconds since Jan, 1st, 1970)
1365086814

so, my guess is, it is seconds since some point in
time in decimal.

HTH,
Herbert


> Mark
> Vk2hmc
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Re: [time-nuts] Is possible precise 1pps?

[Herbert Poetzl]

On Wed, Mar 20, 2013 at 01:48:59PM +0100, Attila Kinali wrote:
> On Mon, 18 Mar 2013 09:21:57 +0100
> "Pieter ten Pierick"  wrote:

>>> The -T models are not that expensive. The problem is that you
>>> have to buy them in batches >30 to get down to a reasonable
>>> price. U-blox seems to have taken the stance, that small
>>> buyers are not really benefitial to their business (which is
>>> understandable when you can sell millions of pieces on the
>>> chinese market). But they nevertheless support these small
>>> buyers trough their webshop where you can buy single pieces
>>> (which is far better than most manufacturers who do not sell
>>> single pieces at all).

>> Sounds like a time-nuts group buy?

> Tried that a year or two ago. Did even get a "special" price
> from u-blox that would usually need higher volumes, but it
> didn't take off.

>   Attila Kinali

May I ask, what the "special" price was, just to get the
right perspective here?

Thanks in advance,
Herbert

> -- 
> The trouble with you, Shev, is you don't say anything until you've saved
> up a whole truckload of damned heavy brick arguments and then you dump
> them all out and never look at the bleeding body mangled beneath the heap
>   -- Tirin, The Dispossessed, U. Le Guin
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Re: [time-nuts] WWVB Clocks don't sync anymore (revisited)

[Herbert Poetzl]

On Wed, Mar 20, 2013 at 11:22:46AM -0400, Chuck Harris wrote:
> The thing is, many of us on the opposite end of the country
> from WWVB have to rely on favorable propagation to make our
> clocks work reliably.  What happens if noon and midnight
> aren't favorable times?

Then you got a problem I guess :)

best,
Herbert

> -Chuck Harris

> Herbert Poetzl wrote:
>> On Wed, Mar 20, 2013 at 02:34:19AM -0400, Bill S wrote:

>>> Interestingly, I have three timepieces that will no longer
>>> synch to wwvb.Two Radio Shack digital clocks and a Casio
>>> wristwatch that I've worn for a couple of years and was always
>>> pretty much dead on. Like Paul, I have an analog Lacrosse clock
>>> that is running correctly. Nothing I've tried will make the
>>> other clocks synch.

>> Maybe this is related to the phase modulation time code
>> protocol used by WWVB since October 29th, 2012.

>> Their website also states that clocks using information
>> from the carrier will no longer work, and that during the
>> transition period (at least March 21st 2013), the PM
>> signal will be turned for for 30 minutes twice a day
>> (noon and midnight MST) so maybe check if the clocks
>> sync then?
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Re: [time-nuts] WWVB Clocks don't sync anymore (revisited)

[Herbert Poetzl]

On Wed, Mar 20, 2013 at 02:34:19AM -0400, Bill S wrote:

> Interestingly, I have three timepieces that will no longer
> synch to wwvb.Two Radio Shack digital clocks and a Casio
> wristwatch that I've worn for a couple of years and was always
> pretty much dead on. Like Paul, I have an analog Lacrosse clock
> that is running correctly. Nothing I've tried will make the
> other clocks synch.

Maybe this is related to the phase modulation time code
protocol used by WWVB since October 29th, 2012.

Their website also states that clocks using information
from the carrier will no longer work, and that during the
transition period (at least March 21st 2013), the PM
signal will be turned for for 30 minutes twice a day
(noon and midnight MST) so maybe check if the clocks
sync then?

best,
Herbert

http://www.nist.gov/pml/div688/grp40/wwvb.cfm

> Bill_S W2FMA

> On 3/19/2013 5:29 PM, paul swed wrote:
>
>> Funny you bring this up. I am just noticing a sharp clock that
>> I always use and it has been accurate. But it did not flip
>> with the time change this time and though it says its locked
>> its off by 45 seconds slow. Yet a lacross clock across the
>> room seems to be on second wise but never flipped with the
>> time change. As I say its just becoming apparent. Regards Paul
>> WB8TSL

>> On Tue, Mar 19, 2013 at 4:55 PM, Clint Turner
>>  wrote:

>>> A few weeks ago I posted a question/comment about some of
>>> my WWVB-based "Atomic" clocks no longer setting themselves
>>> properly. These two clocks, SkyScan #86716, would show the
>>> symbol indicating that they had set themselves, but their
>>> time was drifting away from UTC. Interestingly, they *would*
>>> set themselves exactly once upon installation of the battery,
>>> but never again.

>>> Since that time, I've done a bit of digging around.

>>> The first suspicion was that, perhaps, the NIST had fudged a
>>> bit in the WWVB timecode recently, so I manually decoded a
>>> few frames and analyzed them: Nothing suspicious there.

>>> The next question was if the addition of the BPSK somehow
>>> skewed the timing of the TRF's AGC/threshold - but logically,
>>> this didn't make sense since the clock *did* set itself
>>> exactly ONCE - and it wouldn't have been able to do this at
>>> all were this the case. Out of curiosity I poked around on
>>> the board and found the trace containing the time code and
>>> found that despite the BPSK, its timing was exactly as it
>>> should have been: No surprise there.

>>> This left the clock itself, so I did what any other Time Nut
>>> would do: I built a WWVB simulator.

>>> Initially, I set it to a 2010 date - a time that I knew that
>>> the clock worked properly. I had two clocks: One that I'd
>>> just reset by pulling and replacing the battery while the
>>> other had been "stuck" for a few weeks, not resetting itself
>>> nightly as it should. I put both of these in the coupling
>>> loops from my WWVB simulator and over the next few days, the
>>> recently re-set clock happily synchronized itself while the
>>> other one with the 2013 date was still "stuck." I then reset
>>> that clock and it, too, behaved itself from then on.

>>> I then reset the clock on the simulator to a February 2013
>>> date and time. Initially, both clocks reset themselves to
>>> the current time and date at their next midnight, but after
>>> that, they got "stuck", never resetting themselves at "night"
>>> again.

>>> So, it appears to be a problem with "Broken Sand" (e.g. a
>>> silicon problem).

>>> For the morbidly curious, I have documented my efforts here:

>>> http://ka7oei.blogspot.com/**2013/02/did-nist-break-bunch-**o
>>> f-radio.html>> k-bunch-of-radio.html>- The initial testing

>>> http://ka7oei.blogspot.com/**2013/03/yes-nist-did-break-**
>>> bunch-of-radio.html>> st-did-break-bunch-of-radio.html>- The testing with the WWVB
>>> simulator

>>> 73,

>>> Clint KA7OEI

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Re: [time-nuts] SR620: cal error 23

[Herbert Poetzl]

On Mon, Mar 18, 2013 at 07:34:26PM +0100, Volker Esper wrote:

> Am 18.03.2013 18:00, schrieb Herbert Poetzl:
>> The manual also states that error codes 19-23 are the
>> same as the start values (n - 16), so 23 minus 16 should
>> be the same as '7' i.e. 'stop linearity byte out of range'

> Where do you read that, I can't find it :-/

http://ilrs.gsfc.nasa.gov/docs/timing/sr620_manual.pdf

page 40, search for 'stop tac'

best,
Herbert

> Volker

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Re: [time-nuts] SR620: cal error 23

[Herbert Poetzl]

On Mon, Mar 18, 2013 at 04:28:32PM +0100, Volker Esper wrote:

> Hi all,

> While auto calibrating the SR620 I get the message "cal error  
> 23" - the manual isn't that specific about this message, it
> only states, that error numbers 19 to 23 are caused by Stop
> TAC problems. 

The manual also states that error codes 19-23 are the
same as the start values (n - 16), so 23 minus 16 should
be the same as '7' i.e. 'stop linearity byte out of range'

> However, the counter counts, but I can't do automatic
> calibration any more.

> Anyone having experience with that?

Sorry, no further experience with that

HTH,
Herbert

> Thanks a lot
> Volker

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Re: [time-nuts] Repair of PRS10 Lamp Assembly

[Herbert Poetzl]

On Sun, Mar 17, 2013 at 08:24:37PM -0400, brucekar...@aol.com wrote:
> I am afraid the PRS-10 lamp starting algorithm is a little involved. 
> I believe that once the lamp temperature is in the starting
> range, the microprocessor ramps up the drain and possibly gate 
> voltage of the heating oscillator FET until the bulb strikes   
> as evidenced by a DC signal at the detector.   

> If the lamp overheats (as measured by thermistors imbedded in  
> the back of the lamp block), at some point the microprocessor  
> will reduce the drain voltage to a safe steady-state value.

> The starting constants for each individual PRS-10 are
> factory-set in the unit's programmed software, and as far as
> I know, access to change these settings has not been made
> available yet to end users. 

Assuming that this is the correct image for an PRS-10
(http://goo.gl/Q4ztp), the CPU used looks like an
MC68HC711E20CFN3 (http://goo.gl/Zhxzv) which would mean
that it should be simple to reverse engineer the program
and data stored there 

> This makes it difficult to swap lamps between units.

> I have a PRS-10 with a lamp that is just on the edge   
> of starting properly. Since I cannot change the factory-
> programmed values, I have tried adding a shunt resistor to 
> increase the lamp current to the point where it would reliably 
> start. But, unfortunately, other problems seem to be keeping   
> the unit from working properly.

> The only luck I have had in repairing a non-working PRS-10
> with certainty, was one in a Symmetricom 2500 Time Source
> that turned out to have a failed Mini-Circuits VCO on the
> synthesizer board. Replacing the VCO module restored proper
> operation.

> Perhaps someday the factory will provide end users with access
> to what are now "factory-only" settings.

If there is really an interest in this, just send me
one or maybe two units and I'll give it a try, no promises
though, but I've done a lot of work with motorola CPUs
in the past ...

best,
Herbert

> Bruce, KG6OJI  
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Re: [time-nuts] Datum/Symmetricom X72 Rubidium

[Herbert Poetzl]

On Sat, Mar 16, 2013 at 05:41:11AM -0400, gandal...@aol.com wrote:
> I've had an "interesting" week or so playing with an X72 and
> it turned out not to be quite as straightforward as I first
> expected.

> A google based "X72" search of the list archives seems to throw
> up more questions than answers so I thought it might help a bit
> if I shared what I've learned, whilst hoping others might be
> able to fill in some missing gaps for me too :-)

> One of the attractions of the X72 was the option to use a 1PPS
> input for frequency conditioning, and one of the first things
> I learned was that this depends on the firmware version. This
> feature was introduced with firmware version 5.02 in 2003, and
> this bright and shiny looking just like new X72 turned out to
> have 25,000 hours on the clock and firmware version 4.10 from
> 2002. Lesson one, looks ain't everything :-(

Did you open up the unit completely?
If so, did/could you take/make some photos/scans of the
electronics/components?

best,
Herbert

> Next problem, these are specified at shipment to have
> an accuracy of <+/-5E-11 but obviously they age. Whilst
> Symmetricom does offer analogue and digital options for
> adjustment, more of which in a moment, there's no user
> option to properly adjust the startup frequency, as in the
> FE5680A for example, instead there's a flag that gets set to
> conveniently warn the user when it's time to send their X72
> back to Symmetricom for a "service". As received, the locked
> output frequency of this unit was 9.999,999,986,xx Mhz, the
> xx indicating digits still wandering after lock which may
> reflect more on the less than ideal antenna placement for the
> Thunderbolt providing the counter reference. 

> When finally in a negotiated position to remove the "do not
> remove" warranty stickers both were found to cover access
> holes, one of which led nowhere but the other to a trimmer
> capacitor adjacent to the lamp assembly. 

> Whether or not it was the intended purpose this did allow
> adjustment of the output frequency, unfortunately it ran out of
> steam at 9.999,999,992,xx MHz so was reset to where it started.

> There are two further options for frequency adjustment, not
> including the digitally adjustable CMOS outputs, one is a
> software command that allows an offset to be specified, based
> on the free running frequency and in steps of 2E-12, which
> does allow for reasonable adjustment relative to the startup
> frequency but resets every time power is removed 

> The other is an anologue control input which can be varied from
> 0 to 5 volts and allows adjustment to a few parts in 10^11, but
> which sits at just over 4 volts to bring this one to 10MHz.


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Re: [time-nuts] IEEE-488 Bulletin for Fluke 1953A Counter

[Herbert Poetzl]

On Mon, Mar 04, 2013 at 02:29:53PM -0500, Mike Garvey wrote:
> Does anyone have Application Bulletin 23 (IEEE STD-488) 
> for the Fluke 1953A Counter?

JFI: they seem to be sold for about 10 USD on ebay

best,
Herbert

> Thanks, Mike

> Michael Garvey
> 85 Monument Avenue
> Swampscott, MA 01907-1907 USA
> h: 781 595 4978

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Re: [time-nuts] FE 5860A breakout board

[Herbert Poetzl]

On Fri, Mar 01, 2013 at 07:05:52PM +, Geoff Blake wrote:
> Some two years back, Ian Muir (AKA Gonzo?) produced a 
> breakout board for the FE 5860A, one of which I have. 

FE-5680A I presume?

> Needless to say, I managed to loose (tidy away!) the
> documentation.

Do you have a picture of that breakout board?

> Despite searching the archives and google, I cannot 
> find a link to this.

> perhaps somebody can help.

Maybe I can help, if I see that board ...

best,
Herbert

> Thanks Geoff

> -- 
> #
> Geoff Blake,   G8GNZJO01fq:   Chelmsford,  Essex,  UK
> or   
> Using Linux: Ubuntu 11.04 on Intel or Debian on UltraSparc
> and Apple OS X 10.8.2 Mountain Lion on my Macbook Pro.
> Avoiding Micro$oft like the plague.
> #
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Re: [time-nuts] GPSDO with a RaspberryPi

[Herbert Poetzl]

On Thu, Feb 28, 2013 at 01:26:17AM +0100, Azelio Boriani wrote:
> First try at a simple GPSDO for the RaspberryPi. See here:
> http://www.c-c-i.com/exchange/ for the file PiAutoTIC1.zip
> Thanks to Bob Smither for his file exchange site.

Pardon my ignorance, but where does the 161ms PPS length
come from?

2^24 = 16777216 so with 50/100ns clock intervals, we
should either see 83.88ms or 167.77ms (typo?)

Otherwise, nice project, thanks for sharing and thanks
for releasing it as open-source (btw, you might want
to use some license, like GPLv2 for that).

Nitpick: the SI symbol for second is 's' not 'S', i.e.
lowercase instead of upper, because 'S' stands for
siemens (which is the SI unit of electric conductance)

thanks,
Herbert

> This project is completely open-source, VHDL and C sources are
> available. Can be implemented also with any uP but the C source
> must be heavily modified.
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Re: [time-nuts] FE-5680A DDS Board/PIC Code

[Herbert Poetzl]

On Thu, Feb 28, 2013 at 03:49:55AM +0100, Magnus Danielson wrote:
> On 02/18/2013 10:32 PM, Herbert Poetzl wrote:

>> [ lot of stuff zapped ]

> It would be interesting if fractional resolution of the DDS
> would be developed using the PHASE interface. 

> As PHASE ripples, a carry needs to be sent into the phase
> accumulator of the AD9830, or alternatively fiddling the
> frequency value would help.

While continuously adjusting the phase (via PHASEx) would
probably work, I was more thinking about changing the
FREQx values, which contribute to the phase accumulator.

IMHO this should give a much better result than the abrupt
phase changes and thus a smoother output with less unwanted
noise.

One approach might be to set FREQ0 to the last value below
the desired frequency and FREQ1 to the first value above 
(i.e. FREQ0 + 1) and then toggle FSELECT in a pattern to 
match the fractional part.

FSELECT has a pipeline delay of 6 MCLK, but that doesn't
matter much if you do micro adjustments and FSELECT can be
changed at any time without causing any discontinuity.

And the best part: FSELECT is a small cable soldered onto
the AD9830 which can easily be rerouted to the PIC.

But I haven't found the spare time to dig into yet ...

best,
Herbert

> Anyway, good work!

> Cheers,
> Magnus
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Re: [time-nuts] WWVB

[Herbert Poetzl]

On Fri, Feb 22, 2013 at 06:01:46PM -0500, paul swed wrote:
> Donald from what I have been seeing they are consistent. 

> But there is a 1 hour period up around 1 or 2 pm est that
> they go back to the old modulation and that allows time 
> clocks to lock.

Just for information here (from their web page):

Since October 29, 2012 at 1500 UTC (9:00 AM MDT), NIST
Radio Station WWVB has been broadcasting a phase modulation
(PM) time code protocol that has been added to the legacy
AM/pulse-width-modulation signal. 

This enhancement to the broadcast, which has been tested
throughout 2012, provides significantly improved performance
in new products that are designed to receive it. 

Existing radio-controlled clocks and watches are not 
affected by this enhancement, and continue to work as before.

Disciplined oscillator products that track and lock to the
60 kHz WWVB carrier and were designed to work as frequency
standards, will not work with the PM signal and will now 
become obsolete.

A few radio controlled clocks that used information from the
carrier – specifically the Spectracom NetClock and receivers
manufactured by True Time during the 1970s and 1980s – will 
no longer be able to read the time code and will also be
obsolete.

To allow users of these receivers to migrate to new products,
the plan for implementing the new modulation protocol 
includes a transition period that will extend until at least
March 21, 2013. 

During the transition period, the PM signal will be turned 
off for 30 minutes twice per day, at noon and midnight 
Mountain Standard Time (MST), allowing carrier tracking 
receivers to temporarily acquire the legacy signal.

HTC,
Herbert

> At least thats what the spectracom 8170 does. Then it says 
> its locked for a very long time even though it isn't.

> Regards
> Paul
> WB8TSL

> On Fri, Feb 22, 2013 at 3:35 PM, Donald Henderickx
> wrote:

>> Is wwvb consistent in the testing of there modulation scheme?I find that
>> My Spectracom 8182  will stay in time sync for several days,and then loose
>> it for five or six hours. Is any one else experiencing this?
>> I am thinking of trying my kinemetrics/truetime 60-TF to see if it might
>> function.
>> Don Henderickx
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Re: [time-nuts] Off topic project sort of heart rate monitor NEED BEATS PRE MINUTE TO ANALOG VOLTAGE

[Herbert Poetzl]

On Tue, Feb 19, 2013 at 04:58:04PM -0800, Paul Cianciolo wrote:
> Hello Folks,

First, I cannot speak for the list, as I'm quite new here,
but in general 'Thread Hijacking' is frowned upon :)
(read: start your own thread :)

> I am working on a project intended to convert an analog ECG
> signal to a voltage proportional the heart rate, The actual
> electrodes instrumentation amp is pretty much working fine 
> so no worries there.

> The problem is, and here is where the relationship to time nut
> comes in. The signal output from the instrumentation amplifiers
> will be at a rate of approx 60 BPM or pulses, up to perhaps 90
> BPM.  

> The purpose of this apparatus is to print a rolling chart on
> the screen of a computer of heart BPM and then try different
> technicues of meditaion  and calming technicues to lower my
> heart rate for short periods of time.

That doesn't sound to me like you would actually need a
Voltage, i.e. some other Information from which you can
deduce the current BPM would be fine as well ...

> My first tthought was a frequency to voltage IC like the
> LM2907 or the 2917 but I get the impresiion from the data
> sheets that these chips will not work at these very low 1Hz
> applications,

> Then I thought maybe one of the frequecy counters could be
> configured as a rate meter and output a proportional voltage
> I need.

I wouldn't count the frequency directly, instead, I'd
simply count the intervals, with a counter running at
a known frequency, for example, with a 1kHz or maybe 1MHz
clock, which can be easily done with a $1 microprocessor
The 'counts' for each interval are inverse proportional
to the current BPM, with some averaging you should get
a reasonable result to display on screen.

> No luck here either. 
> Te latter components seem tobe somewhat time relatedand that
> is why I posted here.\\

> Thank you for reading this and for any suggestions you folks might offer.

HTH,
Herbert

> PaulC
> W1VLF

> 1Hxz
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[time-nuts] FE-5680A DDS Board/PIC Code

[Herbert Poetzl]

I'm new to the time-nuts community, so I simply start 
with a short info on how I got into this situation :)
(skip forward to  if not interested)

Not long ago, I decided to build a reasonably good
frequency counter for my personal use and maybe if
the result is simple and elegant, I'll publish the
details so that everybody can build one ...

It was clear to me, that it had to be able to count
up to at least 1GHz and thus show at least nine, 
better ten significant digits, so a precise time base
is required.

After some online searches and investigations, my
best options seemed to get a very stable oscillator
and a high quality time reference to sync with, which 
in turn brought me to the idea to use a cheap rubidium 
normal and somehow tune/measure/sync it via GPS or 
DCF-77/MSF-60.

Reading a lot of documentation and blogs from all over 
the world (sometimes in translation :) shed some light 
on the rubidium normal requirements, which I defined as:

 - has to have a 10MHz output not just the 1PPS
 - has to be programmable (i.e. can be tuned)
 - must be cheap

I quickly found two different RB standard models, 
readily available on ebay for a reasonable price, 
namely the Efratom FRS-C and the FEI FE-5680A.
I finally decided to go with the FE-5680A, mainly
because I liked the package. A seller was quickly
found offering something titled:

 'FE-5680A Rubidium Atomic Frequency Standard 
  Oscillator Transceivers 10Mhz Out'
 'Programmable from 1Hz to 20MHz'

Little did I know what that actually meant ...

When the units (I ordered two of them) arrived, I
couldn't wait to test if they actually work and get
a lock, so I quickly wired them up (according to the
pinout) and provided them with the advised 15V at
up to 2A each. To my astonishment, they heated up
rather quickly and got a lock in a little under two
minutes, so I happily got my scope out to check the
10MHz signal, just to find that there is no such
signal available on the 9pin D-sub connector.

Measuring pins against ground (pin 2) and 15Vx (pin 1)
I figured that neither pin 7 (10MHz) nor pin 8/9
(the rs232 interface for programming) was connected.
and to my great disappointment, pin 6 (1PPS) didn't 
output much either (I later discovered that this was
due to a defective unit, which is now being replaced)
 
After contacting the seller, I opened up the units
to investigate my options (and of course, because
I wanted to take a look inside :), which in turn led
to a number of high resolution scans and photos of
all the bits and pieces.

A (this time) more thorough search on the internet
resulted in a deeper understanding of the various 
options the FE-5680A can have (or usually doesn't 
have) and the inner workings of the different 
FE-5680A models (of course, all labeled FE-5680A :)

The DDS board, which actually can be programmed to
output certain frequencies derived from the 'locked'
1:136 frequency of the rubidium 6.8GHz transition,
caught my attention, as it has both, the '10Mhz'
output and the programming interface, so I decided
to analyze it further ...



The central part on this specific DDS board [1] is 
the AD9830A a Direct Digital Synthesizer (DDS) which
basically produces a sine wave at a well defined
multiple and phase of a given reference frequency.

Besides some other components, this board also 
includes an RS-232C line driver (Sipex SP233A) a
PIC16F84 microcontroller and two 74HC595 8bit shift
registers, with buffered outputs.

I read somewhere, that the blue buttons on that DDS
board can be used to adjust the output frequency,
this should be avoided, mainly because every button
press is an update and will cause a write to the
EEPROM data wearing it out.

Now as I've played with PIC microcontrollers for
a long time, I wanted to know what this specific
controller is doing and how I could use that for my
purposes ...

The chip was quickly removed and the program as well
as configuration memory retrieved (luckily FEI didn't
utilize the code/data protection) and together with 
high resolution scans and photos, a documented and 
verified assembler listing [2] reverse engineered.

Here are the (IMHO) quite interesting findings:

 - both FREQx registers can be adjusted
 - the PHASE0 register can be adjusted
 - none of the changes is permanent,
   unless you explicitely save the settings
 - there are only a few commands, without
   any plausibility checks and/or protection
 - and yes, the buttons increment/decrement
   the FREQx settings and trigger a write to
   the EEPROM after every update.
 - the serial interface is done in software
 - the DDS control words are shifted into
   the 74HC595, buffered and written 


; S STATUS 
;   R=50255057.012932Hz F=2ABB5040
;   OK
;
; F=FREQxREG (set divider)
;   OK
;
; G=PHASE (set phase register)
;   OK
;
; R=YY  RUBIDIUM (set calibrated freq)
;   OK
;   
; E