[time-nuts] Reminder -- upcoming list changes

[John Ackermann N8UR]

Just a reminder that starting this Friday, June 15, postings to the 
febo.com mailing lists will need to use the new addresses -- 
@lists.febo.com instead of @febo.com.  You can start using the new 
addresses now.


The list server will be shut down for an hour or two on Friday to make 
the configuration change.


The transition to the new server will happen over the June 30 weekend -- 
the server will be shut down on Saturday, June 30, so the data can be 
moved to the new provider.  The lists should be back up no later than 
Tuesday, July 3.


By the way, if it wasn't clear in my other message -- after the move, 
the lists will still operate just as they did before, with the same 
administrators and moderators.


John
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[time-nuts] febo.com Mailing List Changes

[John Ackermann N8UR]

Some of you may know that febo.com lives on leased hardware at a data 
center.  That hardware is now at its end of service life, which means it 
won't be supported if it breaks.  After pondering the options for a 
replacement, I've decided that it's time to move away from dedicated 
hardware toward cloud-based services, and to offload some of the 
sysadmin responsibilities to people who know what they are doing.


As part of that, the febo.com mailing lists will be moving to a new list 
hosting provider.  I'm working to make the transition as seamless as 
possible.  You will not need to resubscribe to the mailing lists, or 
change any list settings.  The lists will continue to use the Mailman 
software and web interface, and will work just as they have been.


However, the address for posting messages will change.  Instead of 
sending to, for example, "time-nuts@febo.com" you'll now send to

"time-n...@lists.febo.com" -- just adding "lists." to the domain.

The new addresses should be working now.  On June 15, the old addresses 
will stop working; all postings after that date need to be to

@lists.febo.com.

Around July 1, the lists will move to the new hosting company.  We will 
probably turn the lists off for a day or two during that transition, and 
I'll send a note when that is about to happen.  When the lists come 
back, you should see no further changes.


A note about the list archives, which have been accessible by going to, 
for example, "https://www.febo.com/pipermail/time-nuts;, and which 
Google does a pretty good job of indexing.  Going forward, the archive 
URL will change as well, using the lists.febo.com domain.  That may 
impact search results until Google indexes the new site.  I'll maintain 
the existing archives as of the cutover date at the old URL to mitigate 
the problem.  Between June 15 and July 1, archive access may be a bit flaky.


This change will improve the reliability of the mailing lists, and 
remove several single points of failure.  It should allow the lists to 
continue indefinitely into the future.  I hope that the transition 
doesn't cause you too much inconvenience.  If you have any questions or 
concerns, please contact me directly at j...@febo.com.


John Ackermann
Your SysAdmin
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Re: [time-nuts] Possible new run of TNS-BUF High Isolation, Low Noise Buffer Amp boards

[John Ackermann N8UR]

Good news -- we had enough orders to justify doing a small production 
run of the TNS-BUF isolation amplifiers.  We'll be placing the order 
with our contract manufacturer this week, and expect delivery in six to 
eight weeks.


There will be a few extra boards available, so if you haven't ordered 
yet, there's still time.


John


On 05/08/2018 03:09 PM, John Ackermann N8UR wrote:
Back in October, 2016, TAPR did a build-to-order offering of the TNS-BUF 
low noise, high isolation buffer amplifier.  The original 2016 post is 
attached below.  All of those units sold out, and recently I've had a 
few questions about whether more will be available.


TAPR will do another one-off production run if we can get orders for at 
least 25 boards (the minimum to make manufacturing viable) by *June 1*. 
You can place an order by going to http://tapr.org/kits_tns-buf.  The 
price will be the same as the previous production -- $119 plus shipping.


If we receive orders for at least 25 boards by June 1, we will charge 
credit cards and place the production order with our contract 
manufacturer.  If we don't get 25 orders, we'll cancel the project and 
your card will not be charged.


We expect to ship finished TNS-BUF boards about 60 days after placing 
the production order.


Best regards,
John

 Forwarded Message 
Subject: [time-nuts] TNS-BUF High Isolation, Low Noise Buffer Amp Available
Date: Wed, 5 Oct 2016 10:15:46 -0400
From: John Ackermann N8UR 

I've previously mentioned a high performance buffer amplifier called the 
"TNS-BUF" that I built based on a design by Dr. Bruce Griffiths with 
further input from John Miles. Key numbers are:


*  Phase noise -140dBc/Hz at 1 Hertz offset, noise floor -175dBc/Hz.
     (PN plot attached)
*  Reverse isolation greater than 100dB; low enough that I can't make a
     trustworthy measurement.
*  Gain from -10 to +7 dB from 1 to 30 MHz; maximum output >18dBm.
*  Nominal 18VDC operation, but works down to 12V with lowered
     maximum output level.

There's information, including performance data and schematic, at
http://www.febo.com/pages/TNS-BUF

There seems to be some interest in an amplifier like this, so TAPR has 
decided to do a limited production run.  The amp is built with surface 
mount parts, so we thought an assembled and tested board was better than 
a kit.  The price will be $119 each.  But we have no idea how much 
interest there is, and we need to build a minimum of 25 units to make 
production feasible.


So, here's the deal:  you can order your TNS-BUF at

http://tapr.org/kits_tns-buf

through *October 20*.  If we receive orders for at least 25 boards by 
then, we will charge credit cards and place the production order with 
our contract manufacturer.  If we don't get 25 orders, we'll cancel the 
project and credit cards will not be charged.  There's no guarantee that 
boards will be available for later order.


We expect about 60 days between placing the manufacturing order and 
receipt of the boards at TAPR.  We'll ship to customers ASAP after 
receipt.  So that means you can expect to receive your order shortly 
after January 1.


So, go to http://tapr.org/kits_tns-buf now to place your order before 
the deadline!


John




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[time-nuts] A Request to the List

[John Ackermann N8UR]

TVB is traveling and not on-line as much as usual, so in his absence I'm 
going to ask everyone to please consider his request a couple of weeks 
ago to think before you post.


Please keep in mind that time-nuts isn't a chat room, and that every 
message doesn't require an individual response.  It's much better to 
have one thoughtful post than a dozen written on the fly.


Remember that 1800 "new message" flags go up each time you post.

Thanks,
John
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[time-nuts] Possible new run of TNS-BUF High Isolation, Low Noise Buffer Amp boards

[John Ackermann N8UR]

Back in October, 2016, TAPR did a build-to-order offering of the TNS-BUF 
low noise, high isolation buffer amplifier.  The original 2016 post is 
attached below.  All of those units sold out, and recently I've had a 
few questions about whether more will be available.


TAPR will do another one-off production run if we can get orders for at 
least 25 boards (the minimum to make manufacturing viable) by *June 1*. 
You can place an order by going to http://tapr.org/kits_tns-buf.  The 
price will be the same as the previous production -- $119 plus shipping.


If we receive orders for at least 25 boards by June 1, we will charge 
credit cards and place the production order with our contract 
manufacturer.  If we don't get 25 orders, we'll cancel the project and 
your card will not be charged.


We expect to ship finished TNS-BUF boards about 60 days after placing 
the production order.


Best regards,
John

 Forwarded Message 
Subject: [time-nuts] TNS-BUF High Isolation, Low Noise Buffer Amp Available
Date: Wed, 5 Oct 2016 10:15:46 -0400
From: John Ackermann N8UR <j...@febo.com>

I've previously mentioned a high performance buffer amplifier called the 
"TNS-BUF" that I built based on a design by Dr. Bruce Griffiths with 
further input from John Miles. Key numbers are:


*  Phase noise -140dBc/Hz at 1 Hertz offset, noise floor -175dBc/Hz.
(PN plot attached)
*  Reverse isolation greater than 100dB; low enough that I can't make a
trustworthy measurement.
*  Gain from -10 to +7 dB from 1 to 30 MHz; maximum output >18dBm.
*  Nominal 18VDC operation, but works down to 12V with lowered
maximum output level.

There's information, including performance data and schematic, at
http://www.febo.com/pages/TNS-BUF

There seems to be some interest in an amplifier like this, so TAPR has 
decided to do a limited production run.  The amp is built with surface 
mount parts, so we thought an assembled and tested board was better than 
a kit.  The price will be $119 each.  But we have no idea how much 
interest there is, and we need to build a minimum of 25 units to make 
production feasible.


So, here's the deal:  you can order your TNS-BUF at

http://tapr.org/kits_tns-buf

through *October 20*.  If we receive orders for at least 25 boards by 
then, we will charge credit cards and place the production order with 
our contract manufacturer.  If we don't get 25 orders, we'll cancel the 
project and credit cards will not be charged.  There's no guarantee that 
boards will be available for later order.


We expect about 60 days between placing the manufacturing order and 
receipt of the boards at TAPR.  We'll ship to customers ASAP after 
receipt.  So that means you can expect to receive your order shortly 
after January 1.


So, go to http://tapr.org/kits_tns-buf now to place your order before 
the deadline!


John


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Re: [time-nuts] WWVB: measuring local 60 KHz noise

[John Ackermann N8UR]

Long ago I did some WWVB signal-to-noise measurements with an HP 3586C 
selective voltmeter (commonly used by the FMT-nuts).  I measured the signal 
power at 60.0 kHz with 20 Hz bandwidth.  Then I measured the power a small 
offset plus and minus  (100 Hz?  I don't recall), and took the mean of the two 
to get the noise power.  I used a voltage-probe antenna.  

Since all readings were taken with the same bandwidth I didn't bother 
normalizing to 1 Hz, and just used the dBm difference between the signal and 
mean noise as the result.  I took measurements every 5 minutes or so to capture 
the 24 hour cycle of SNR.

John

On May 6, 2018, 1:09 PM, at 1:09 PM, Charles Steinmetz  
wrote:
>Hal wrote:
>
>> I assume the problem is noise.  Is there any simple way to measure
>the noise
>> around 60 KHz?  How about not so simple?
>>
>> Extra credit for a way that others nuts can reproduce so we can
>compare the
>> noise at my location with other locations.
>
>For any location near a city, the noise level (QRM and QRN -- mostly
>the 
>former unless there is storm activity within a few hundred km) is 
>shockingly high.  High enough to be clearly seen and measured with a 
>good spectrum analyzer.  So the *simplest* way (but not necessarily the
>
>cheapest, depending on what is in your lab already) is to use a good 
>spec an with noise integration over the band of interest (e.g., HP
>3585A 
>or B).  You get noise density readings in volts per root Hz.  Divide by
>
>the antenna length and you have volts per root Hz per meter.
>
>Lacking a suitable spec an, any receiver with a reasonably narrow rx
>B/W 
>and a calibrated, input-referred detector can be used.  Wave analyzers 
>(frequency-selectable voltmeters, e.g., HP 3586) are good candidates,
>as 
>are some commercial receivers with calibrated "S" meters (e.g., Ten-Tec
>
>RX340).  It would also be pretty easy to design a simple "sniffer"-type
>
>receiver (input op-amp, active filter, logarithmic detector feeding a 
>standard 1mA meter movement) that could be calibrated by design from 
>first principles and that everyone interested could build for, perhaps,
>
>$25-30.
>
>In the suburbs of a fairly large US city with aerial electric service,
>I 
>generally see noise densities measured in tens to hundreds of uV per 
>root Hz per meter below 100kHz.  In other, similar locations I have
>seen 
>as much as hundreds of mV or more per root Hz per meter.  It depends on
>
>local factors (whether the electric service is buried or aerial, how 
>well the power utility maintains its equipment, how far away the
>nearest 
>industrial neighborhood is, how far between dwellings, how much noisy 
>technology the neighbors use, etc, etc.).
>
>In order to compare with others, everyone needs to use the same
>antenna. 
>  There are lots of possibilities, but for the sake of universality I 
>recommend a 1m vertical whip.  Everyone can make one of those.
>
>Note that this sort of antenna is NOT the best type to minimize
>received 
>noise and maximize received S/N ratio.  For that, you generally want a 
>balanced, shielded loop.
>
>Best regards,
>
>Charles
>
>
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Re: [time-nuts] Wavecrest DTS2075

[John Ackermann N8UR]

It's more a burst-mode and averaging analyzer like the HP 5371/5372.  But it 
can do sustained time interval measurements if you mess around enough with the 
settings.  And the resolution is down in the very low picoseconds.

But it's big, awkwardly shaped, and has a jet turbine fan.

John

On Apr 10, 2018, 6:00 PM, at 6:00 PM, Bruce Griffiths 
 wrote:
>Its more accurate and has less measurement noise than the SR620.
>
>The input bandwidth is also greater.
>
>The accuracy is no better than that of a modern TDC chip, however its
>measurement noise is lower.
>
>Bruce
>
>> 
>> On 11 April 2018 at 07:17 Gerhard Hoffmann 
>wrote:
>> 
>> I have been offered a DTS2075. Is this generally regarded as a
>step
>> 
>> forward if you already have a SR620 or is it more or less the
>same
>> 
>> league? Are there any hidden pearls or caveats?
>> 
>> TIA and best regards,
>> 
>> Gerhard
>> 
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Re: [time-nuts] Cheap jitter measurements

[John Ackermann N8UR]

I want to jump on Tom's post, and Bob's note at 1:14 on Saturday (that 
begins with "Just to be very clear..."  They both raise an important 
point about measurements.


With both NTP and GPSDO measurements a lot of folks focus heavily on 
what the "black box" is reporting about itself.  But self-contained 
measurements are really unrelated to actual performance.


As Bob mentioned, in a GPSDO you can look at tempco, humidco, voltageco, 
and all sorts of other things but the overall point of the system is to 
make those meaningless: the control loop(s) compensate for them.  If 
those internal error generators are reduced, it may make the system's 
work easier, but that improvement will have no effect on the quality of 
the output if the control loop is already properly compensating for it.


And in NTP, the software reports all sorts of interesting measurements, 
but none of them really tell you how close the computer's clock is to a 
local reference.  As Tom said, the real test is how the time tick coming 
out of the box compares with the time tick going into it.


The bottom line is that no self-contained measurement can tell you 
actual performance.  The *only* way to do that is to compare your box 
with an external reference whose error bounds are known.


After all, this is why we're time-nuts -- every time you acquire a 
clock, you also need to acquire a better clock to test it with. :-)


John

On 04/08/2018 03:36 PM, Tom Van Baak wrote:

What do you mean by "jitter" and what do you really want to do?

I mean jitter as NTP defines jitter.  Whatever that is.


I think you need to figure out what you want to do so you don't fool yourself.

ntpd is a PLL.  There is a low pass filter in the control loop.  It will
track the low frequency wander of the source.


Gary, Hal, Leo,

My mental model of a black box computer running NTP is that I should be able to 
give it a pulse (e.g., via parallel, serial, GPIO) and it tells me what time it 
was. Use a GPSDO / Rb / picDIV to generate precise pulses. Compare the known 
time of the pulse with the time the box says it was. Repeat many times, collect 
data, look at the statistics; just as we would for any clock.

Similarly, the box should be able to give me a pulse at a known time. In this 
case it records the time it thinks the pulse went out, and your GPSDO / Rb / 
TIC makes the actual measurement. Again, collect data and look at the 
statistics; just as we would for any clock.

Imagine the black box has two BNC connectors; one accepts an input pulse to be 
timed; one outputs a pulse at certain times. This allows a complete analysis of 
NTP operation. Should be true for both client or server. If you get down to 
nanosecond levels make sure to use equal length cables.

To me this better than relying on NTP to tell you how NTP is doing, which as 
far as I can tell from live plots on the web, is all that most people do. 
Instead use real, external, physical measurement. The internal NTP stats are 
fine for tracking the performance of the PLL, but don't confuse that with 
actual timing.

So this is why I'm excited to hear Gary wants a Rb timebase and a sub-ns 
counter. Someone will finally measure NTP for real, not rely on the internal 
numbers of NTP measuring itself. Or at least I hope that's what Gary is up to.

/tvb

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Re: [time-nuts] Ultralink

[John Ackermann N8UR]

Hi Brooke --

Yes, all the chips on the board are low power devices.  I'm measuring 
the receiver as drawing 0.9 MA at about 2.3 volts.


Update -- I moved the receiver and farted around with the wiring, and 
now the S-Meter is off the peg, responds to orientation changes, and I 
actually got a couple of indications of bits being decoded.  So, I think 
the hardware is working fine.


However, there must be a lot of local interference as decoding is very 
erratic and I'm nowhere near getting a full sequence.  I don't have any 
experience at this location with WWVB reception, so I'm not sure what to 
expect.  At my previous Ohio house a mile south of here the signals were 
very good and there were no noticeable problems with the Spectracom 
receivers (may they rest in peace).  Next step is to experiment with 
receiver placement.


John

On 03/30/2018 03:15 PM, Brooke Clarke wrote:

Hi John:

The U4226B chip operates at very high impedance levels in order to 
minimize battery drain in its main application, battery powered clocks.

So some sort of buffer is needed on all the output pins.

The 333 model, with the analog meter, was made for the folks working for 
WWVB as a way for them to know the transmitter was on the air.

http://www.prc68.com/I/timefreq.shtml#WWVBrcvr
http://www.prc68.com/I/Loop.shtml (WWVB)


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Re: [time-nuts] Ultralink

[John Ackermann N8UR]

On 03/30/2018 03:39 AM, Hal Murray wrote:


t...@leapsecond.com said:

I updated http://leapsecond.com/museum/ulio/ with more manuals, and many
exterior / interior photos of the 301 module.


Thanks. My 301 says it is a 30TH Rev-A - mostly through hole parts.  Same
layout.


Mine is the same.  Circuit is very simple.  The 20 pin IC is the U4226B 
receiver chip and it has two external 60 kHz filter resonators.  The 8 
pin DIP is a TLV2770C op amp which seems to be a buffer to drive the S 
meter from the very high impedance AGC test point on the receiver chip. 
And I am guessing that the 2N3904 transistor is a buffer for the time 
code output.


The modular cable connecting the receiver to the decoder is wired 
straight through, not reversed as most telephone cables are.  My fear is 
that someone (like me) might at one point have used a reverse cable and 
thus put reverse polarity on the board; I don't see any reverse power 
protection.


Later today I'll tap into the four conductors on the cable and see what 
signals I see on them, and also look for signs of life on the receiver chip.


BTW -- Donald Resor pointed me to UTSource which shows several Chinese 
vendors as having them in stock.  I get nervous about whether they are 
the real thing or not, but will probably order a couple just in case. 
The chip is a 20 pin TSSOP package, which isn't too hard to rework but 
before putting hot air on the receiver board there are one or two 
surrounding parts one would want to remove to avoid collateral damage.


John
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Re: [time-nuts] Ultralink WWVB receiver manuals?

[John Ackermann N8UR]

Thanks to another list memo, I got the basic manual.  Got it fired up 
and while it does things, I think there's a problem.  The S Meter is 
pinned all the way over to the right (very, very strong signal) and 
stays there no matter how I shield the antenna.  And I never see any 
decoded bits.  I hope the receiver chip (U4226B, unobtanium except from 
China) isn't shot.  Will do more testing when I get some cycles free.


It would be very nice to have a direct NIST time source in the lab 
again, complete with PPS output.


Thanks!
John


On 03/29/2018 05:55 PM, Tom Van Baak wrote:

Congrats on your acquisition. The Ultralink WWVB receivers are very nice. It 
should still work -- it's an AM subcode (not carrier phase) receiver. If you 
have more questions let me know. These modules were the darling of precise time 
at the turn of the century; before mobile phones, before GPS was affordable. 
Ultralink discontinued the product line within a few years when the market for 
WWVB-based timing dried up.

Manuals here: http://leapsecond.com/museum/ulio/

Good question on the cable. If you don't see it in the manual let me know; I'll 
dig out my cable and have a look. Note the inner 4 of 6 pins are Vcc, TCO, AGC, 
gnd.

/tvb

- Original Message -
From: "John Ackermann N8UR" <j...@febo.com>
To: "Discussion of precise time and frequency measurement" <time-nuts@febo.com>
Sent: Thursday, March 29, 2018 8:57 AM
Subject: [time-nuts] Ultralink WWVB receiver manuals?



I just acquired an Ultralink WWVB timecode receiver -- more
specifically, model 301 receiver and model 333 decoder.

I'm looking for documentation on these guys.  Anyone have a manual
they'd be willing to share?

The key questions are really just two:  (a) is the 6P6C modular cable
connecting the receiver and decoder straight, or reversed, and (b) what
are the four DIP switches on the back of the 333 used for?

Thanks for any info.

John
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[time-nuts] Ultralink WWVB receiver manuals?

[John Ackermann N8UR]

I just acquired an Ultralink WWVB timecode receiver -- more 
specifically, model 301 receiver and model 333 decoder.


I'm looking for documentation on these guys.  Anyone have a manual 
they'd be willing to share?


The key questions are really just two:  (a) is the 6P6C modular cable 
connecting the receiver and decoder straight, or reversed, and (b) what 
are the four DIP switches on the back of the 333 used for?


Thanks for any info.

John
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Re: [time-nuts] Introduction, new list member, Ms Tisha Hayes, AA4HA

[John Ackermann N8UR]

The impedance mismatch with the A or B models is't a real issue unless you're 
doing precise amplitude measurements.  Lots of folks use them for FMT work 
without issues. There are adapters available or buildable to deal with the odd 
Telco connectors.

John

On Mar 29, 2018, 3:04 AM, at 3:04 AM, Ruslan Nabioullin  
wrote:
>On Wed, Mar 28, 2018 at 9:49 PM, Tisha Hayes 
>wrote:
>
>> Perry and I would make our pilgrimages to the Huntsville Ham Fest and
>> usually I ended up buying equipment from him. One of the items he
>sent my
>> way was an HP 3586B that I am finally beginning to put to use.
>>
>
>Hmm that measuring receiver model (diffs can be found in:
>http://www.militaryradio.com/manuals/HP/hp3586-a-b-c.pdf ) was
>apparently
>intended for testing and troubleshooting purposes for those ancient
>FDM-based POTS trunk systems, not as a general-purpose HF measuring
>receiver (the HP 3586C)---I'm not sure how well they would function as
>HF
>receivers for WWV and CHU following impedance adaptation (b/c it
>doesn't
>have a 50 ohm unbalanced interface).
>
>In my case, I supply my time transfer volunteers with the following
>setup:
>
>vertical antenna -> TVSS -> preamplifier -> military rackmount
>preselector
>-> military/intelligence rackmount parametric demodulator or HP 3586C
>->
>Xeon NTP server via soundcard
>
>with GNU/Linux daemon software which commands the preselector and
>demodulator via GPIB.
>
>Still, WWV/CHU-derived public NTP nodes are virtually nonexistent, and
>therefore there's a strong need for them, regardless of the
>sophistication
>of the receiver, due to the pitfalls of GNSS.
>
>-Ruslan
>
>-- 
>Ruslan Nabioullin
>Wittgenstein Laboratories
>rnabioul...@gmail.com
>(508) 523-8535
>50 Louise Dr.
>Hollis, NH 03049
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Re: [time-nuts] ULN regulator with more current capability than LT3042?

[John Ackermann N8UR]

Thanks, all.  I think I'll end up using the 3042 with pass transistor, 
partly for reasons of cost.  I have no idea whether paralleling two 
3042s would result in lower noise from the device, and there are already 
three or four fairly pricey chips on the board.


I appreciate all the info!

John


On 03/18/2018 06:43 PM, Charles Steinmetz wrote:

Tom wrote:


Run two in parallel for twice the current and less noise?


This is actually a better solution than using an LT3045, for two 
reasons.  First, as Tom noted, by paralleling two devices, the noise is 
reduced by sqrt 2 = ~1.4:


"Designed as a precision current reference followed by a high 
performance voltage buffer, the LT3042 is easily paralleled to increase 
output current, spread heat on the PCB and further reduce noise -- 
output noise decreases by the square-root of the number of devices in 
parallel."  [LT Journal of Analog Innovation, v25 n1 Apr 2015]. 



Second, it reduces the dissipation of each regulator, so they run 
cooler.  And as LT says, it allows spreading the heat on the board (but 
it is not advisable to put them too far apart).


The primary disadvantage is that two 3042s cost about half again more 
than one 3045.  Also, board space may be a factor in some applications.


So, unless you are extremely tight on board space or the ~1.5x cost 
increase is prohibitive, two 3042s in parallel are a better solution 
than one 3045 if you are seeking the lowest noise possible.


Best regards,

Charles


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Re: [time-nuts] ULN regulator with more current capability than LT3042?

[John Ackermann N8UR]

Thanks, Bruce!!!

On 03/18/2018 04:19 PM, Bruce Griffiths wrote:

Use an LT3045, its the 0.5A version of the LT3042.

Bruce

On 19 March 2018 at 09:13 John Ackermann N8UR <j...@febo.com> wrote:


Reviving the conversation about superb voltage regulators, I am looking
for one to run the analog and PLL bits of a high performance frequency
synthesizer chip.

The current drain looks to be about 160-180 mA at 1.8 V, which is
uncomfortably close to the limit for the LT3042 (200 mA).  The
manufacturer's evaluation board uses a MAX8869, which appears to be
nowhere in the LT3042's league, but will source 1 A.

Any recommendations for a 1.8 V regulator a little beefier than the
LT3042, but with similar noise performance?

Thanks!
John
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[time-nuts] ULN regulator with more current capability than LT3042?

[John Ackermann N8UR]

Reviving the conversation about superb voltage regulators, I am looking 
for one to run the analog and PLL bits of a high performance frequency 
synthesizer chip.


The current drain looks to be about 160-180 mA at 1.8 V, which is 
uncomfortably close to the limit for the LT3042 (200 mA).  The 
manufacturer's evaluation board uses a MAX8869, which appears to be 
nowhere in the LT3042's league, but will source 1 A.


Any recommendations for a 1.8 V regulator a little beefier than the 
LT3042, but with similar noise performance?


Thanks!
John
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[time-nuts] PulsePuppy Status

[John Ackermann N8UR]

For those who ordered a PulsePuppy oscillator carrier board from TAPR -- 
we quoted early February delivery so I wanted to give a quick update.


The boards are in hand and the kits ready to go, except... USPS managed 
to lose the box of programmed PICs on its way from my house to the TAPR 
office.  I should be getting a new batch from Mouser tomorrow, and have 
them on the way back to the office by Monday (via UPS this time).  With 
luck, we should be able to ship kits by the end of next week.


Sorry for the delay; if not for the lost package we would have shipped 
last week.


(If you're not familiar with the PulsePuppy, here's the link: 
https://www.tapr.org/kits_pp.html.  We'll have plenty of kits available 
once the PIC chip problem is solved.)


John
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Re: [time-nuts] Rakon HSO-14

[John Ackermann N8UR]

Here's a link to data on an 8607-008.  You may recognize the bottom plot 
from a recent posting. :-)  But the ADEV and PN data at the top of the 
page is from the factory test data.  The ADEV doesn't explicitly say so, 
but I strongly believe it's based on comparison with a "gold standard" 8607.


http://febo.com/pages/oscillators/bva/

John


On 02/04/2018 02:38 PM, Bob kb8tq wrote:

Hi

Obviously you need two more 8607’s ….. :)

I suspect you are correct and the OCXO is doing better than the close in data 
suggests.

Bob


On Feb 4, 2018, at 8:33 AM, Tom Van Baak  wrote:

FYI: here's an old plot where I evaluated an Oscilloquartz 8607 BVA against a 
H-maser. It gets down to 8e-14 but is likely a bit better. On this plot, I 
suspect the short-term numbers were not the BVA oscillator or the TSC 5110A 
analyzer, but the H-maser.

/tvb
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Re: [time-nuts] More on SiLabs 5340

[John Ackermann N8UR]

On 01/29/2018 04:54 PM, Chris Caudle wrote:

On Mon, January 29, 2018 2:38 pm, John Ackermann N8UR wrote:

The close-in phase noise is quite amazing, but the floor is much worse
than in free-run mode.


That phase noise plot doesn't look quite right, what PLL bandwidth did you
set?


Sorry for the earlier null reply.  I just used the settings that the 
ClockBuilder software came up with (which IIRC don't offer any choices 
about loop bandwidth in the "wizard").  I haven't yet dug into the 
register options, but I'm sure that there are ways to optimize.


John
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Re: [time-nuts] More on SiLabs 5340

[John Ackermann N8UR]

On Jan 29, 2018, 4:54 PM, at 4:54 PM, Chris Caudle <ch...@chriscaudle.org> 
wrote:
>On Mon, January 29, 2018 2:38 pm, John Ackermann N8UR wrote:
>> The close-in phase noise is quite amazing, but the floor is much
>worse
>> than in free-run mode.
>
>That phase noise plot doesn't look quite right, what PLL bandwidth did
>you
>set?
>
>-- 
>Chris Caudle
>
>
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Re: [time-nuts] Si5340 synthesizer chip performance

[John Ackermann N8UR]

The reference was a 5 MHz Wenzel ULN and the instrument was a Miles TimePod.

On Jan 28, 2018, 8:13 PM, at 8:13 PM, Jerry Hancock <je...@hanler.com> wrote:
>John, what device did you use for the test?
>
>
>Regards,
>
>Jerry
>
>
>Jerry Hancock
>je...@hanler.com
>(415) 215-3779
>
>> On Jan 28, 2018, at 4:23 PM, John Ackermann N8UR <j...@febo.com>
>wrote:
>> 
>> I received the Si5340A evaluation board from Digikey on Friday and
>fired it up yesterday.  I used the SiLabs "ClockBuilder" software to
>configure four outputs -- 10 MHz, 15 MHz, 29.999 999 9 MHz, and 144.2
>MHz -- all using the 45 MHz crystal that comes with the EVM.  Attached
>is a phase noise plot of the 10 MHz and 29.999 999 9 MHz signals.  I
>would say this isn't too bad!  This performance is certainly sufficient
>for any of the RF work I have in mind.
>> 
>> The ADEV was another matter -- about 1e-9 at 1 second, working its
>way uphill from there.  But what do you expect from a bare crystal?
>> 
>> John
>> 
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[time-nuts] Si5340 synthesizer chip performance

[John Ackermann N8UR]

I received the Si5340A evaluation board from Digikey on Friday and fired 
it up yesterday.  I used the SiLabs "ClockBuilder" software to configure 
four outputs -- 10 MHz, 15 MHz, 29.999 999 9 MHz, and 144.2 MHz -- all 
using the 45 MHz crystal that comes with the EVM.  Attached is a phase 
noise plot of the 10 MHz and 29.999 999 9 MHz signals.  I would say this 
isn't too bad!  This performance is certainly sufficient for any of the 
RF work I have in mind.


The ADEV was another matter -- about 1e-9 at 1 second, working its way 
uphill from there.  But what do you expect from a bare crystal?


John

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[time-nuts] TNS-BUF bare boards

[John Ackermann N8UR]

Some time ago TAPR did a one-time run of a very low noise, very high 
isolation buffer amplifier.  The assembled boards are sold out, but we 
had some extra blank boards made and finally (after a long story) got 
those delivered from Hungary to the office.


If you're interested in a TNS-BUF board, they are $15 plus shipping and 
you can order via the button at http://tapr.org/kits_tns-buf.html


I'm working on a publishable bill of materials for the parts to stuff 
the boards, and will put a link to it on that web page ASAP.


John
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Re: [time-nuts] Slightly OT: interest in a four-output, ultra-low jitter, synthesizer block?

[John Ackermann N8UR]

Yes, I was planning to include bypasses, and I've been convinced to put 
at least the 1.8V regulator on the board as well.  And to think about 
the interconnects.


Adding the crystal does make the layout more complex -- they put a 
ground pour on its own layer underneath it, and I think (but am not 
sure) that the connections complicate selecting an external oscillator. 
I'll look into the pain tradeoff.


On 01/25/2018 04:08 PM, Robert LaJeunesse wrote:

John, I appreciate your minimalist goal, but I'll second Bill's section about including 
the power supply voltage regulator and bypassing. Finding a good regulator with wideband 
line regulation/rejection could prove a real search, and such a fast chip as the Si5340 
will need excellent broadband supply bypassing. So keep these key components tight to the 
chip, on the same PCB obviously. The need for a 4- to 6-layer board screams "keep 
critical loops tight"! FYI a regulator (of needed RF performance) producing 3.3V for 
VDDA will likely have an absolute max input voltage of 6V or so. Having a 5V supply 
requirement will not be a serious limitation of the overall system design. I'm sure you 
know the 1.8V supply regulators should not be fed from VDDA (3.3V), but I'll mention it 
anyway.

With that much on the PCB adding a small crystal can't add significantly to the cost, 
so why not? It allows R of the chip and outputs before having to hook up one's 
10MHz reference. As such crystal quality / stability / etc. are of little concern - 
just size & cost.

I also like the previous suggestion of castellated connections on the board edge - 
easy to solder to a board and easy to solder wires to. If you make the castellations 
on 0.1" (or 2mm) centers then it becomes possible to use common header pins as 
well. Just keeping your options open there.

Bob L.


Sent: Thursday, January 25, 2018 at 3:23 PM
From: "John Ackermann N8UR" <j...@febo.com>
To: time-nuts@febo.com
Subject: Re: [time-nuts] Slightly OT: interest in a four-output, ultra-low 
jitter, synthesizer block?

Hi Bill --

And that's exactly what I *don't* want to do. :-)  The reason is that I
have several different projects in mind (and everyone else will have
their own requirements) and only want to deal with the difficult package
once.

The idea is to make a minimal carrier to deal with the tiny part and
six-layer board.  Then all the ancillary stuff (including the MCU that's
needed to program the chip) goes onto the board designed for that
project.  This isn't intended to be a finished product, just a building
block.

73,
John

On 01/25/2018 03:12 PM, wb6bnq wrote:

Hi John,

Thanks for the response.  Here is my 2 cents:

Well, due to the level of difficulty in chip mounting, I would prefer to
see a complete project. I.E., power supply for a single input of 12
volts and regulators the necessary chip values, proper input protection
for the 10 MHz input level and single ended outputs of the appropriate
levels (I am assuming more than 3 volts) or an amplifier stage for
arriving at such.  Equally have RF connectors (SMA would be good) on the
board perhaps.

Of course as cheap as possible, hi hi.  A carrier board arrangement
would be useless to me.  My application would be to provide signals for
things like my Quicksilver SDR receiver, among other uses.

If you are interested, I can show you a nice little ABS (I think) box
that has EMI built-in that I used for a project that should be more than
large enough for your needs.

Thanks for reading,

73....BillWB6BNQ


John Ackermann N8UR wrote:


Hi Bill --

I should have been more clear: this design will be for a simple case:
one reference clock input, four outputs.  The chip can do all sorts of
fancy tricks, but I'm looking for a source of four low jitter outputs
derived from a 10 MHz external reference (not using crystal or
on-board oscillator).  Many of the pins are unused in that configuration.

I'm not looking to make a universal carrier for the chip, but to meet
what I suspect is a common time-nut/ham radio desire for a clean
multi-channel synthesizer.

On 01/25/2018 02:02 PM, wb6bnq wrote:


Hi John,

After looking at the data sheet, it seems way more involved then just
making a carrier board for it.  Besides the power supply
requirements, various design selections would dictate different
circuit layouts for different purposes.  Even trying to do a general
purpose application would possibly require having several different
output configurations and possibly a couple of input configurations
as well.  That would imply a rather detailed PCB and that chip
package style is a serious pain in the ass for [what amounts to]
hobbyists.  So it would seem the logical course would be to do
serious design application and see if an in-house component mounting
job would be feasible.

I notice that the data sheet says the jitter specs are only best when
using The internal crystal oscillator frequency between 48 and 54
MHz.

Re: [time-nuts] Slightly OT: interest in a four-output, ultra-low jitter, synthesizer block?

[John Ackermann N8UR]

Hi Bill --

And that's exactly what I *don't* want to do. :-)  The reason is that I 
have several different projects in mind (and everyone else will have 
their own requirements) and only want to deal with the difficult package 
once.


The idea is to make a minimal carrier to deal with the tiny part and 
six-layer board.  Then all the ancillary stuff (including the MCU that's 
needed to program the chip) goes onto the board designed for that 
project.  This isn't intended to be a finished product, just a building 
block.


73,
John

On 01/25/2018 03:12 PM, wb6bnq wrote:

Hi John,

Thanks for the response.  Here is my 2 cents:

Well, due to the level of difficulty in chip mounting, I would prefer to 
see a complete project. I.E., power supply for a single input of 12 
volts and regulators the necessary chip values, proper input protection 
for the 10 MHz input level and single ended outputs of the appropriate 
levels (I am assuming more than 3 volts) or an amplifier stage for 
arriving at such.  Equally have RF connectors (SMA would be good) on the 
board perhaps.


Of course as cheap as possible, hi hi.  A carrier board arrangement 
would be useless to me.  My application would be to provide signals for 
things like my Quicksilver SDR receiver, among other uses.


If you are interested, I can show you a nice little ABS (I think) box 
that has EMI built-in that I used for a project that should be more than 
large enough for your needs.


Thanks for reading,

73BillWB6BNQ


John Ackermann N8UR wrote:


Hi Bill --

I should have been more clear: this design will be for a simple case: 
one reference clock input, four outputs.  The chip can do all sorts of 
fancy tricks, but I'm looking for a source of four low jitter outputs 
derived from a 10 MHz external reference (not using crystal or 
on-board oscillator).  Many of the pins are unused in that configuration.


I'm not looking to make a universal carrier for the chip, but to meet 
what I suspect is a common time-nut/ham radio desire for a clean 
multi-channel synthesizer.


On 01/25/2018 02:02 PM, wb6bnq wrote:


Hi John,

After looking at the data sheet, it seems way more involved then just 
making a carrier board for it.  Besides the power supply 
requirements, various design selections would dictate different 
circuit layouts for different purposes.  Even trying to do a general 
purpose application would possibly require having several different 
output configurations and possibly a couple of input configurations 
as well.  That would imply a rather detailed PCB and that chip 
package style is a serious pain in the ass for [what amounts to] 
hobbyists.  So it would seem the logical course would be to do 
serious design application and see if an in-house component mounting 
job would be feasible.


I notice that the data sheet says the jitter specs are only best when 
using The internal crystal oscillator frequency between 48 and 54 
MHz. It was unclear to me that the same would apply to using the 
non-crystal inputs.


Perhaps you could indicate what you are attempting to do with it and 
how you are going to accomplish your goals ?


73BillWB6BNQ


John Ackermann N8UR wrote:

After the recent discussion about Silicon Labs clock generators, I 
looked at their Si5340A part and think it will be useful for a ham 
radio project I'm working on.  While it can do other things, for my 
use it would use a 10 MHz input clock and generate 4 independent 
outputs in the range of 100 kHz to 1028 MHz.  Its jitter is <100fs, 
which translates to "not bad" phase noise.  Here's the data sheet if 
you're interested:


http://www.silabs.com/documents/public/data-sheets/Si5341-40-D-DataSheet.pdf 



The challenge is that the chip is a 7x7 mm 44-QFN package and really 
wants to be put on a six-layer circuit board.  That's doable, but 
challenging, for home assembly.


Rather than designing the chip into a larger circuit board, I'm 
thinking of doing a small "carrier" board that would include just 
the chip and critical bypass caps and have headers to plug into the 
main board. Then, you could just drop the carrier into a 
project-specific board and not have to worry about the complex 
layout and mounting.  I have a contract manufacturer who can build 
these up, if there's enough quantity to justify the setup cost.


If you'd be interested acquiring in one or more of these, please 
drop me a line off-list (jra at febo dot com).  I don't think this 
will be a TAPR project, but if there's enough interest to build 25 
of these carriers, I can probably make that happen.  And remember -- 
this is just the chip; you'll need to provide the rest of the circuit.


John
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Re: [time-nuts] Slightly OT: interest in a four-output, ultra-low jitter, synthesizer block?

[John Ackermann N8UR]

Hi Bill --

I should have been more clear: this design will be for a simple case: 
one reference clock input, four outputs.  The chip can do all sorts of 
fancy tricks, but I'm looking for a source of four low jitter outputs 
derived from a 10 MHz external reference (not using crystal or on-board 
oscillator).  Many of the pins are unused in that configuration.


I'm not looking to make a universal carrier for the chip, but to meet 
what I suspect is a common time-nut/ham radio desire for a clean 
multi-channel synthesizer.


On 01/25/2018 02:02 PM, wb6bnq wrote:

Hi John,

After looking at the data sheet, it seems way more involved then just 
making a carrier board for it.  Besides the power supply requirements, 
various design selections would dictate different circuit layouts for 
different purposes.  Even trying to do a general purpose application 
would possibly require having several different output configurations 
and possibly a couple of input configurations as well.  That would imply 
a rather detailed PCB and that chip package style is a serious pain in 
the ass for [what amounts to] hobbyists.  So it would seem the logical 
course would be to do serious design application and see if an in-house 
component mounting job would be feasible.


I notice that the data sheet says the jitter specs are only best when 
using The internal crystal oscillator frequency between 48 and 54 MHz. 
It was unclear to me that the same would apply to using the non-crystal 
inputs.


Perhaps you could indicate what you are attempting to do with it and how 
you are going to accomplish your goals ?


73BillWB6BNQ


John Ackermann N8UR wrote:

After the recent discussion about Silicon Labs clock generators, I 
looked at their Si5340A part and think it will be useful for a ham 
radio project I'm working on.  While it can do other things, for my 
use it would use a 10 MHz input clock and generate 4 independent 
outputs in the range of 100 kHz to 1028 MHz.  Its jitter is <100fs, 
which translates to "not bad" phase noise.  Here's the data sheet if 
you're interested:


http://www.silabs.com/documents/public/data-sheets/Si5341-40-D-DataSheet.pdf 



The challenge is that the chip is a 7x7 mm 44-QFN package and really 
wants to be put on a six-layer circuit board.  That's doable, but 
challenging, for home assembly.


Rather than designing the chip into a larger circuit board, I'm 
thinking of doing a small "carrier" board that would include just the 
chip and critical bypass caps and have headers to plug into the main 
board. Then, you could just drop the carrier into a project-specific 
board and not have to worry about the complex layout and mounting.  I 
have a contract manufacturer who can build these up, if there's enough 
quantity to justify the setup cost.


If you'd be interested acquiring in one or more of these, please drop 
me a line off-list (jra at febo dot com).  I don't think this will be 
a TAPR project, but if there's enough interest to build 25 of these 
carriers, I can probably make that happen.  And remember -- this is 
just the chip; you'll need to provide the rest of the circuit.


John
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[time-nuts] Slightly OT: interest in a four-output, ultra-low jitter, synthesizer block?

[John Ackermann N8UR]

After the recent discussion about Silicon Labs clock generators, I 
looked at their Si5340A part and think it will be useful for a ham radio 
project I'm working on.  While it can do other things, for my use it 
would use a 10 MHz input clock and generate 4 independent outputs in the 
range of 100 kHz to 1028 MHz.  Its jitter is <100fs, which translates to 
"not bad" phase noise.  Here's the data sheet if you're interested:


http://www.silabs.com/documents/public/data-sheets/Si5341-40-D-DataSheet.pdf

The challenge is that the chip is a 7x7 mm 44-QFN package and really 
wants to be put on a six-layer circuit board.  That's doable, but 
challenging, for home assembly.


Rather than designing the chip into a larger circuit board, I'm thinking 
of doing a small "carrier" board that would include just the chip and 
critical bypass caps and have headers to plug into the main board. 
Then, you could just drop the carrier into a project-specific board and 
not have to worry about the complex layout and mounting.  I have a 
contract manufacturer who can build these up, if there's enough quantity 
to justify the setup cost.


If you'd be interested acquiring in one or more of these, please drop me 
a line off-list (jra at febo dot com).  I don't think this will be a 
TAPR project, but if there's enough interest to build 25 of these 
carriers, I can probably make that happen.  And remember -- this is just 
the chip; you'll need to provide the rest of the circuit.


John
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Re: [time-nuts] trimble Thunderbolt, how to get 25 or 27 mHz from it??

[John Ackermann N8UR]

Hi Mark --

Thanks!  To clarify, when you say you've found "it" acceptable, you're 
referring to the 5328?


What caught my eye about the 5351 was the three (or eight) outputs.  My 
idea was to build a board that would provide independent LO oscillators 
for multiple VHF/UHF transverters.  It looks like the 5328 has two 
outputs, which is still useful but would require putting two or three of 
them on the board.  Which isn't the end of the world.


Thanks,
John


On 1/19/2018 8:56 AM, Mark Goldberg wrote:

On Jan 19, 2018 6:01 AM, "John Ackermann N8UR" <j...@febo.com> wrote:


Sorry to hijack the thread, but the Si5351 looks interesting for another
project I'm working on.  I know it specifies "low jitter" but has anyone
looked at the phase noise?  Is it usable for RF applications?




Datasheet states jitter in the 40-70 ps range. That is not very good. If
you want something suitable for RF applications, look at the Si5328. It has
jitter on the order of 300fs.

I believe Leo Bodnar uses it in his GPSDOs and I can confirm the phase
noise and Allan Deviation others have found and it is suitable for me for
RF applications. It is not nearly as good as the Thunderbolt though. It
will generate almost any frequency you want.

Mark





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Re: [time-nuts] trimble Thunderbolt, how to get 25 or 27 mHz from it??

[John Ackermann N8UR]

Sorry to hijack the thread, but the Si5351 looks interesting for another 
project I'm working on.  I know it specifies "low jitter" but has anyone 
looked at the phase noise?  Is it usable for RF applications?


Thanks,
John


On 01/18/2018 08:53 AM, D. Jeff Dionne wrote:

Chris,

You don't need to do that.  The SiLabs part will accept the 10MHz sin from an 
OCXO directly into the XA pin.  That pin normally connects to a crystal, so 
there is a high gain amp in the chip to square it up already... I did the tests 
a while back, see the thread here:

https://www.silabs.com/community/timing/forum.topic.html/si5351_msop10_packag-wocK

Caveats: others had trouble with biasing, and found just squaring the OCXO up 
first worked for them. SiLabs software is not set up to allow any other 
frequencies except 25 or 27MHz, so you do need to calculate the register values 
yourself.

J.


Is there an easy way to get 25 or 27 MHz from my Trimble Thunderbolt as a 
reference clock at 1v P to P square wave for a Si5351a synthesizer chip please? 
I have the David Partridge divider board from way back that is still going 
strong, but 25 MHz is not an option as it divides only. Thanks, please keep 
replies to the level an idiot might comprehend :) -- Best Regards, Chris 
Wilson. mailto: chris at chriswilson.tv

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Re: [time-nuts] Stable32 now available

[John Ackermann N8UR]

FWIW, for me the hardest part of working with Stable32 is getting the 
input scaling and other parameters like timestamps correct.  If you 
think like a mathematician, you'll probably do fine.  But I don't, and 
when working in particular with frequency data it always takes me a few 
tries to get it right.


But Stable32 is superb software, and this is a wonderful contribution. 
Thanks, Bill!


John


On 01/02/2018 09:46 AM, Tom Van Baak wrote:

 From "Paul Alfille" :
Is the code be available, or just the compiled binary?


I've asked Bill for clarification and will relay any information.



 From "paul swed" 
I suspect we need a Stable32 for dummies book.


When I first started using Stable32 I tried to document each step. See examples 
like:

http://leapsecond.com/pages/ahm-phm/maser1.htm
http://leapsecond.com/pages/doug-rb/
http://leapsecond.com/pages/osa8607-dat/
http://leapsecond.com/pages/hp5065-dat/
http://leapsecond.com/pages/8607-drift/



 From "Magnus Danielson" 
Now, the code needs to be maintained. I personally also would like to
see it run natively on Linux, it does run on Linux under Wine.


Stable32 seems highly integrated with the "graphic/win" plotting package 
(www.sciend.com). That may be one of the problems porting the code to unix. But hang on, 
and we'll let Bill tell us for sure.



 From "Dr. David Kirkby" 
Perhaps someone who has both the book and the software, would comment if
the book is very out of date, or would still be useful.


The book is wonderful. The software hasn't fundamentally changed.
Bill also maintains a fantastic site at http://www.wriley.com/ where you will 
find 100+ documents worth reading.

/tvb

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Re: [time-nuts] TAPR "PulsePuppy" Pot Selection

[John Ackermann N8UR]

I didn't really notice much backlash, though when setting oscillators I try to 
approach (slowly) from one direction until it's "good enough" and then stop, to 
avoid that problem.

On Dec 24, 2017, 11:28 AM, at 11:28 AM, Dana Whitlow <k8yumdoo...@gmail.com> 
wrote:
>John,
>
>Do you notice a backlash effect when homing in on the desired setting
>with
>those
>tripots?  I last used such things back in the 1980's, and remember
>often
>having
>enough backlash to make close trimming rather difficult.
>
>I wonder if they have gotten better in that regard.
>
>Dana
>
>On Sun, Dec 24, 2017 at 9:58 AM, John Ackermann N8UR <j...@febo.com>
>wrote:
>
>> I'm glad that the PulsePuppy post spawned some good discussion!
>>
>> The pot I'm using is a Bournes 3296W-1-103LF which is a 25-turn, 10K,
>> cermet pot, spec'd at 100ppm/degree, so it's not anything super
>fancy. The
>> number of turns provides decent setability, and it seems to be a good
>match
>> for the class of oscillator the PulsePuppy is designed for -- I found
>that
>> I could trim the Isotemp oscillator without problems.
>>
>> I'll admit up front that the PulsePuppy wasn't designed as a host for
>> ultra-stable oscillators.  I tried to keep the circuit board size and
>cost
>> down, as well as the number of components that users would have to
>> install.  And since the EFC trimmer is one of those user-installed
>parts,
>> it's possible to substitute as nice a pot as you'd like.  I have one
>unit
>> that's hooked up to an external precision pot with a turn-counter
>dial
>> (just because it was there).
>>
>> John
>> 
>>
>> On 12/24/2017 03:57 AM, Mark Goldberg wrote:
>>
>>> Can you specify what pot you have used? I am using some for my TCXO
>boards
>>> and am not quite happy with the settability or mechanical stability.
>>> resulting in noise and higher Allan Deviation.
>>>
>>> A low noise regulator driving it also helped.
>>>
>>> I subscribe to the opinion to not use any extra resistors. When the
>pot is
>>> used as a voltage divider, theoretically it should have the same TC
>>> throughout, so temperature effects should not affect the divide
>ratio or
>>> the output. Only the input impedance of the control voltage input to
>the
>>> oscillator relative to the effective resistance of the pot will
>provide
>>> some effect with temperature.
>>>
>>> Mark
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Re: [time-nuts] TAPR "PulsePuppy" Pot Selection

[John Ackermann N8UR]

I'm glad that the PulsePuppy post spawned some good discussion!

The pot I'm using is a Bournes 3296W-1-103LF which is a 25-turn, 10K, 
cermet pot, spec'd at 100ppm/degree, so it's not anything super fancy. 
The number of turns provides decent setability, and it seems to be a 
good match for the class of oscillator the PulsePuppy is designed for -- 
I found that I could trim the Isotemp oscillator without problems.


I'll admit up front that the PulsePuppy wasn't designed as a host for 
ultra-stable oscillators.  I tried to keep the circuit board size and 
cost down, as well as the number of components that users would have to 
install.  And since the EFC trimmer is one of those user-installed 
parts, it's possible to substitute as nice a pot as you'd like.  I have 
one unit that's hooked up to an external precision pot with a 
turn-counter dial (just because it was there).


John

On 12/24/2017 03:57 AM, Mark Goldberg wrote:

Can you specify what pot you have used? I am using some for my TCXO boards
and am not quite happy with the settability or mechanical stability.
resulting in noise and higher Allan Deviation.

A low noise regulator driving it also helped.

I subscribe to the opinion to not use any extra resistors. When the pot is
used as a voltage divider, theoretically it should have the same TC
throughout, so temperature effects should not affect the divide ratio or
the output. Only the input impedance of the control voltage input to the
oscillator relative to the effective resistance of the pot will provide
some effect with temperature.

Mark
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Re: [time-nuts] New product: the TAPR "PulsePuppy"

[John Ackermann N8UR]

Absolutely... the plot is mainly to show what to expect from the little OCXO, 
not the board.  It ain't a BVA, but for the price and size, it's not bad.

On Dec 23, 2017, 4:56 PM, at 4:56 PM, Bob kb8tq <kb...@n1k.org> wrote:
>Hi
>
>Looks neat !!!
>
>It is a pretty good bet that everything you see in the ADEV plot is a
>function of the 
>specific OCXO you put on the board. Put another way, the. board’s ADEV
>is way
>better than the ADEV of the OCXO. It’s a very safe bet that everything
>past 2 seconds
>or is the OCXO. 
>
>Bob
>
>> On Dec 23, 2017, at 4:00 PM, John Ackermann N8UR <j...@febo.com>
>wrote:
>> 
>> I've developed a little board called the PulsePuppy that supports
>surplus OCXOs in the common "Eurocase" form factor to provide outputs
>at 10 MHz, or at 1 PPS/10 PPS/100PPS using an on-board 12F675 PIC with
>one of TVB's picDIV firmware images.
>> 
>> The attached pictures show one prototype unit in closeup, and a panel
>of three that are used for TICC counter production testing (providing
>one 10 MHz and two independent PPS outputs).  Also attached is an ADEV
>plot of the inexpensive Isotemp OCXO131-100 oscillator I'm using to
>give an idea of the performance you can expect from these small
>oscillators (they and others like them are available from several eBay
>sources for <$30).
>> 
>> The PulsePuppy is available from TAPR as a semi-kit and can be
>ordered at http://tapr.org/kits_pp.html for $69.  We expect to ship the
>kits in mid-February (delivery of the boards from our contract
>manufacturer is the gating factor).
>> 
>> The assembly manual with schematics can be downloaded at
>http://www.tapr.org/~n8ur/PulsePuppy_Manual.pdfm but here are the specs
>in brief:
>> 
>> * Footprint for either Eurocase OCXO or Crystek CXOH20-BP-10.000
>>  TCXO (TAPR has a bunch of these TCXOs remaining from another project
>>  and, while they last, is offering them bundled with the PulsePuppy
>>  for an attractive price).
>> 
>> * PPS divider uses TVB PD-13 firmware that includes capability to
>>  synchronize to an external clock.
>> 
>> * TTL-level output at jumper-selectable 10 MHz, 100 PPS, 10 PPS,
>>  or 1 PPS rates.
>> 
>> * A BNC output connector is included, but the board contains a
>footprint
>>  to install a user-provided SMA.
>> 
>> * 25-turn EFC trimmer with 0-5V range.
>> 
>> * Option to support sine-wave as well as square wave oscillators.
>> 
>> * Board dimensions are 1.5 x 3.5 inches.
>> 
>> TAPR is offering the PulsePuppy as a "semi-kit" that includes the
>printed circuit board with all surface-mount components installed, and
>a handful of through-hole parts (like voltage regulators, jumpers, and
>connectors) for the user to install.  By leaving these parts for the
>user, the board can be customized -- for example to use different
>voltages or to support a sine-wave oscillator.
>> 
>> Note that the kit DOES NOT include the oscillator, unless you buy the
>Crystek TCXO bundle.
>> 
>> Happy Holidays to all!
>> 
>> John
>>
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Re: [time-nuts] New product: the TAPR "PulsePuppy"

[John Ackermann N8UR]

Sorry, a typo got into the URL for the manual.  Remove the extraneous 
"m" after ".pdf": http://www.tapr.org/~n8ur/PulsePuppy_Manual.pdf


On 12/23/2017 04:00 PM, John Ackermann N8UR wrote:
I've developed a little board called the PulsePuppy that supports 
surplus OCXOs in the common "Eurocase" form factor to provide outputs at 
10 MHz, or at 1 PPS/10 PPS/100PPS using an on-board 12F675 PIC with one 
of TVB's picDIV firmware images.


The attached pictures show one prototype unit in closeup, and a panel of 
three that are used for TICC counter production testing (providing one 
10 MHz and two independent PPS outputs).  Also attached is an ADEV plot 
of the inexpensive Isotemp OCXO131-100 oscillator I'm using to give an 
idea of the performance you can expect from these small oscillators 
(they and others like them are available from several eBay sources for 
<$30).


The PulsePuppy is available from TAPR as a semi-kit and can be ordered 
at http://tapr.org/kits_pp.html for $69.  We expect to ship the kits in 
mid-February (delivery of the boards from our contract manufacturer is 
the gating factor).


The assembly manual with schematics can be downloaded at 
http://www.tapr.org/~n8ur/PulsePuppy_Manual.pdfm but here are the specs 
in brief:


* Footprint for either Eurocase OCXO or Crystek CXOH20-BP-10.000
   TCXO (TAPR has a bunch of these TCXOs remaining from another project
   and, while they last, is offering them bundled with the PulsePuppy
   for an attractive price).

* PPS divider uses TVB PD-13 firmware that includes capability to
   synchronize to an external clock.

* TTL-level output at jumper-selectable 10 MHz, 100 PPS, 10 PPS,
   or 1 PPS rates.

* A BNC output connector is included, but the board contains a footprint
   to install a user-provided SMA.

* 25-turn EFC trimmer with 0-5V range.

* Option to support sine-wave as well as square wave oscillators.

* Board dimensions are 1.5 x 3.5 inches.

TAPR is offering the PulsePuppy as a "semi-kit" that includes the 
printed circuit board with all surface-mount components installed, and a 
handful of through-hole parts (like voltage regulators, jumpers, and 
connectors) for the user to install.  By leaving these parts for the 
user, the board can be customized -- for example to use different 
voltages or to support a sine-wave oscillator.


Note that the kit DOES NOT include the oscillator, unless you buy the 
Crystek TCXO bundle.


Happy Holidays to all!

John


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[time-nuts] TICC counters available again

[John Ackermann N8UR]

TAPR sold out the first run of TICC timestamping counters but we just 
took delivery of a second batch, and we're now taking orders.  See 
http://tapr.org/kits_ticc for details.



John

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Re: [time-nuts] chrony vs ntpd

[John Ackermann N8UR]

Jim, I thought about using an RF-input sync pulse for alignment during 
the Solar Eclipse measurement experiment, but ended up running out of 
time to implement it.  But some very crude experiments indicated that 
it's not hard to generate an edge out of a PPS that creates a comb well 
past HF.  My idea was to do a divide-by-sixty to end up with 
pulse-per-minute rather than PPS.  The lower rate would be less annoying 
to filter out of the results.


I'm interested to hear if you end up doing this, and if so how.

John


On 10/28/2017 12:04 PM, jimlux wrote:
Now that I have successfully connected my GPS receiver to my beagle and 
I'm getting pps ticks into the driver, etc. (thanks to info from several 
folks on this list!) the question arises of whether to use ntpd or chrony.


For my particular application, I'm more interested in synchronizing time 
on the local machine, not necessarily being a NTP server - all of my 
beagles have a GPS on them.  Of course, there may be times when a GPS 
doesn't work, or something else comes up where it would be useful for 
one of the machines to "get time" from somewhere else.


What I am doing is using the Beagle to capture RF samples (RTL-SDR) in a 
distributed array, with wireless connections among the nodes.  The 
processing isn't necessarily real-time (maybe later..), for now, it's 
"trigger some seconds of capture at approximately the same time" and 
post process in matlab/octave.


There's all kinds of nondeterministic latency issues with the 
USB/RTL-SDR path, so I'm under no illusion that I can capture samples 
aligned to the 1pps.  However, what I *can* do is generate a "sync 
pulse" from the 1 pps and feed it into the RTL's RF input in some (TBD) 
way.
And the 1pps might give me a clever way to calibrate the frequency drift 
of the RTLSDR's clock.


Right now, I'm interested in HF signals (so the period is 30 ns at the 
top end, and 500 ns at the bottom end)




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Re: [time-nuts] Distribution divider/amplifier for 10MHz GPSDO

[John Ackermann N8UR]

On 10/23/2017 04:52 PM, Hal Murray wrote:

But if any of the EXT REF are low-z inputs, that won't work so well.


Unless there is only one.  Then you can use it as the last one and you don't
need the explicit terminator.


Good point.
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Re: [time-nuts] Distribution divider/amplifier for 10MHz GPSDO

[John Ackermann N8UR]

To some extent, it depends on the load presented by each device.  The 
"EXT REF" input on many pieces of test equipment is fairly high 
impedance (maybe 10k?) and you can drive several of those with a single 
output, putting a 50 ohm load at the end of the line to provide a 
reasonable termination.*  I seem to recall that three HP boxes worked 
nicely off one line, but when I added a fourth things got flaky.


But if any of the EXT REF are low-z inputs, that won't work so well.

FWIW, Spectracom had a distribution system (8140 series) that had 
amplified "tap" boxes that were daisy-chained together on a single coax 
run.  The driver put 12 volts DC on the cable along with 10 MHz, and 
that powered the taps.  You could put several taps on a single line.  I 
once measured the phase noise of the system and while it wasn't up to a 
really good distribution amplifier, it was perfectly adequate for normal 
RF testing.


John

* Mismatch causes reflections, which can screw up square wave edges or 
sine wave zero-crossings, increasing jitter.  SWR is usually a bigger 
issue for RF distribution than amplitude loss.


On 10/23/2017 01:49 PM, Jeremy Elson wrote:

I was about to ask a related question of the list: when do you need a
distribution amplifier, and when is it sufficient to just have a single
(linear) run of coax?

I have a GPSDO (Nick Sayer's device) that I want to use to feed a few other
pieces of equipment in my lab (an HP5335A, John Ackermann's beautiful TICC,
and a Rigol signal generator). Is it safe to have RG174 coming out of the
GPSDO, tapping into it with a BNC T-junction that plugs into the back of
each device that needs the 10mhz input, and then terminating the strand
with a 50 ohm terminator? (In other words, the way thinnet Ethernet was
wired back in the day.) As long as the signal goes in a straight line, not
a "Y" (i.e. no cables attached to the t-junction taps, just a direct input
into a high-z input) it seems like it should work. Do I need a distribution
amplifier? Or is that, say, if the signal needs to split off in multiple
directions and you don't want to fill your lab with a space-filling curve
of coax?

-Jeremy

On Mon, Oct 23, 2017 at 10:26 AM, Bob kb8tq  wrote:


Hi

The correct answer to any real question like this is “that depends”.

For anything that I normally run as test gear, noise outside a very narrow
bandwidth really
does not matter much. The test gear *assumes* (by design) that the
reference signal going
into the “ref in” jack is not very clean. It does various tricks with
filters and PLL’s to “scrub”
the input.

If we are talking about the reference into one side of a phase noise test
set, then
the situation is a bit different. The test set is simply going to tell me
what the combined
noise is on the two inputs. If one is significantly more noisy than the
other, that’s pretty
much all I will see. In this case, my answer is “don’t use a distributed
signal”. Use a
stand alone source as your reference and isolate it from the rest of the
world.

In any case, making a super duper distribution gizmo and feeding it with a
noisy signal
is not going to make the signal any better. Most GPSDO’s have relatively
noisy outputs.
Some are better than others. None that I have seen on the surplus market
are what
I would call quiet at the output jack of the GPSDO. They either have an
ocean of spurs
or a lot of phase noise. Some have both ….

Any time you boost a bunch of signals up to high levels, you create “crud”
running around your
lab / shack. One of the most basic questions should always be “do I really
need this signal?”. Next
should be “how can I have a shorter run?”.  I have many pieces of gear
that are rarely used.
They use odd references. When I need to use them I rig a reference. That
gets shut down
once the gear goes back to storage. …. no more birdies every 100 KHz …. No
need for
tripple shielded coax ….

Simple answer:

Square up the 10 MHz (or whatever) by matching it into a 5.5 V powered
high speed CMOS
gate. The NC7SZ series is one of many families you can use. A NC7SZ125 is
not a bad gate
to pick. Distribute the square wave to however many output amps as you
need. Each one
is another of the same gates with the output matched via a 50 ohm to 50
ohm lowpass Tee network
with a low Q ( < 2). Likely pad down the output a bit to keep it at a
rational level.  Build up however
many you need for however many frequencies you require. Very normal linear
regulator chips
are fine for the power. Careful bypassing and solid ground planes are
always a good idea.
Parts cost wise, postage is likely to cost you more than the components.
There are …. errr…
many thousands …. of multi output amps of this basic  design out there ….
they seem to
work pretty well.

Yes, there are *lots* of possible twists and turns to this. I’m only
guessing about the gear you
are trying to run and what you are trying to do with it.

Bob






On Oct 23, 2017, at 12:45 PM, Tom Van Baak 

Re: [time-nuts] sine to square wave circuits - performance data?

[John Ackermann N8UR]

The inductor in the T2-Mini is nothing special.

On Oct 4, 2017, 12:57 PM, at 12:57 PM, Attila Kinali  wrote:
>On Wed, 4 Oct 2017 12:02:35 +1300 (NZDT)
>Bruce Griffiths  wrote:
>
>> I could measure the PN of the TAPR variant of the Wenzel circuit
>> as well as the PN of the comparator based circuit (with CMOS output
>buffer).  
>
>
>BTW: one thing that has been bothering me with the TAPR variant of the
>Wenzel circuit is the 100µH inductor in the tail of the diff-pair.
>As it presents an impedance of approximately 6k at 10MHz it is cruical
>to the working of the diff-pair (which would otherwise be just two
>independent transistors). But I was unable to find a 100µH inductor
>with a self-resonance frequency significantly higher than 10MHz.
>Quite to the contrary, most seem to mingle around 1MHz. This poses
>two questions:
>
>1) does the TADD2 mini use a special inductor?
>
>and
>
>2) Given the 100µH inductor has an SFR somewhere in the range of 1-5MHz
>and is likely to have significant core losses around and/or above
>10MHz,
>doesn't this limit the performance of the circuit quite significantly?
>
>I have been thinking of replacing the inductor with a current source
>(simple current mirror) and at least in the spice simulations it looks
>decent. No idea of the noise performance, though.
>
>   Attila Kinali
>-- 
>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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[time-nuts] First results of eclipse data recording

[John Ackermann N8UR]

(This is more amplitude than frequency related, but thought it might be 
interesting to the group.  If not, sorry for the intrusion.)


I used three software defined radios to record just under 1 TB of data 
during the eclipse period from my cottage at Beaver Island, Michigan, 
over 8 hours from 1400 to 2200 UTC.  Frequencies recorded included the 
entire AM broadcast band and four ham radio bands, one of which also 
covers WWV at 10 MHz.  (Obligatory time-nuts/FMT-nuts: the receivers 
were either locked to an FTS4100 cesium standard, or had reference 
markers derived from it.)


It's taken a few days just to aggregate and back up the data.  Last 
night I was able to do the first actual processing.


This initial result is a "spectrum movie" showing the AM broadcast band 
from 0.500 to 2.00 MHz over the 8 hour test period, recorded by a Red 
Pitaya SDR at 2.5 megasamples/second.  It will take more work to 
separate noise/spurs from real signals but it does look like carriers 
came up out of the noise during/after the eclipse period.


The movie was created with a Gnuradio script reading the recorded data 
and displaying an FFT plot, which was captured with a screenshot tool 
every five seconds.  I then turned the images into an .mp4 movie at 30 
frames per second, so the 8 hour period runs by in a bit over 3 minutes. 
 I used a deep FFT (8192 points) with long averaging to get rid of as 
much of the crud as possible.


Blog post with some details here: http://blog.febo.com/wp/?p=202

Get directly to the movie on YouTube here: https://youtu.be/bqRhfCiD8Pw

There's lot more analysis to be done, but I thought this was a necessary 
(and interesting) first step.


73,
John
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Re: [time-nuts] Fwd: [hpsdr] SDR experiment for the solar eclipse

[John Ackermann N8UR]

That experiment is happening, too.  Folks will be monitoring WWV and CHU 
in narrowband mode with the same tools they use in the frequency 
measuring tests.  (You can't really do direct phase comparisons on HF 
frequencies because between the noise and the ionospheric effects, 
including doppler shift, it's really hard to lock to the RF cycle the 
way you can at VLF.)


We were originally going to put a 5071A-locked beacon on three ham 
bands, but decided WWV and CHU would be better sources, and logistics 
were turning into a problem: I'm going to be doing my wideband recording 
from a cottage in northern Michigan.  But I'm still a time-nut, so the 
receiver will be GPSDO-controlled, and there will be a stratum 1 NTP 
server in the cottage to provide timestamps. :-)


John

On 08/03/2017 03:57 PM, Alan Melia wrote:
A Time Nut would measure phase change across the path of totality using 
GPS locked SDR receivers :-)) As was done on the Eclipse that passed 
between the UK and Iceland a couple of years ago. Keflavik NRK's 
ionospheric signal was returned from inside the path of totality to most 
of the north of the UK, giving a good measure of the change in height of 
the "apparent reflection height" in the D-layer.


The quoted program looks a bit scattergun..lets record everthing and 
see what's there.
Hopefully it will involve a lot of school kids and maybe interest them 
in science and electronics. If it does that it will be more useful that 
we could imagine.


Alan
G3NYK

- Original Message ----- From: "John Ackermann N8UR" <j...@febo.com>
To: "Discussion of precise time and frequency measurement" 
<time-nuts@febo.com>

Sent: Thursday, August 03, 2017 8:10 PM
Subject: [time-nuts] Fwd: [hpsdr] SDR experiment for the solar eclipse


This is a little off-topic, but thought some of the group might be 
interested... so please forgive the interruption.


John


 Forwarded Message 
Subject: [hpsdr] SDR experiment for the solar eclipse
Date: Thu, 3 Aug 2017 15:07:57 -0400
From: John Ackermann N8UR <j...@febo.com>
To: fmt-n...@yahoogroups.com, HPSDR list <hp...@lists.openhpsdr.org>

* High Performance Software Defined Radio Discussion List *

I've been working with the "HamSci" group to set up an experiment for 
the solar eclipse: wideband recording of several HF bands before, 
during, and after the eclipse to look for propagation changes (or 
anything else that happens).  All are welcome to participate in the 
experiment, and this is a *perfect* application for our SDRs!


Here's the HamSci web page:
http://hamsci.org/2017-eclipse-hf-wideband-recording-experiment

Various SDRs and programs have wideband recording capability.

Radios that support the HPSDR "old protocol" (which include 
Hermes-based boards as well as the Red Pitaya and possibly others) can 
do an even better trick: they can record multiple slices of the HF 
band simultaneously, thanks to work by Tom McDermott N5EG.


Hermes can do 4 receivers (tested), Mercury/Metis/Atlas systems should 
handle 3 (not tested), and the Red Pitaya can support 6 (tested).  
This means that we can record most of the 80M band, and all of 40, 30, 
and 20M, in one gulp to look for effects of the eclipse -- frequency 
shift, propagation enhancement/reduction, noise floor, etc.


I've written a Gnuradio .grc program that used N5EG's driver to record 
multiple receivers.  By default it's configured for four receivers on 
80/40/30/20M, but that's easy to change.  I'll be posting that 
software to the TAPR github at https://github.com/TAPR as soon as 
we've done a bit more testing.


This software runs on Linux and may work on Windows (I haven't had a 
chance to try, but Gnuradio has been ported to Windows).  Recording 4 
384kHz channels does take some computing horsepower and uses a lot of 
disk space -- about 3MB per receiver per second.  My prior-generation 
i7 machine with solid state drive seems to handle it OK.


If you're interested in participating in this experiment, please (a) 
check out the HamSci web page; (b) check the ttps://github.com/TAPR in 
a day or two to grab the software and docs; and (c) feel free to 
contact me directly with any questions.


73,
John N8UR
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[time-nuts] Fwd: [hpsdr] SDR experiment for the solar eclipse

[John Ackermann N8UR]

This is a little off-topic, but thought some of the group might be 
interested... so please forgive the interruption.


John


 Forwarded Message 
Subject: [hpsdr] SDR experiment for the solar eclipse
Date: Thu, 3 Aug 2017 15:07:57 -0400
From: John Ackermann N8UR <j...@febo.com>
To: fmt-n...@yahoogroups.com, HPSDR list <hp...@lists.openhpsdr.org>

* High Performance Software Defined Radio Discussion List *

I've been working with the "HamSci" group to set up an experiment for 
the solar eclipse: wideband recording of several HF bands before, 
during, and after the eclipse to look for propagation changes (or 
anything else that happens).  All are welcome to participate in the 
experiment, and this is a *perfect* application for our SDRs!


Here's the HamSci web page:
http://hamsci.org/2017-eclipse-hf-wideband-recording-experiment

Various SDRs and programs have wideband recording capability.

Radios that support the HPSDR "old protocol" (which include Hermes-based 
boards as well as the Red Pitaya and possibly others) can do an even 
better trick: they can record multiple slices of the HF band 
simultaneously, thanks to work by Tom McDermott N5EG.


Hermes can do 4 receivers (tested), Mercury/Metis/Atlas systems should 
handle 3 (not tested), and the Red Pitaya can support 6 (tested).  This 
means that we can record most of the 80M band, and all of 40, 30, and 
20M, in one gulp to look for effects of the eclipse -- frequency shift, 
propagation enhancement/reduction, noise floor, etc.


I've written a Gnuradio .grc program that used N5EG's driver to record 
multiple receivers.  By default it's configured for four receivers on 
80/40/30/20M, but that's easy to change.  I'll be posting that software 
to the TAPR github at https://github.com/TAPR as soon as we've done a 
bit more testing.


This software runs on Linux and may work on Windows (I haven't had a 
chance to try, but Gnuradio has been ported to Windows).  Recording 4 
384kHz channels does take some computing horsepower and uses a lot of 
disk space -- about 3MB per receiver per second.  My prior-generation i7 
machine with solid state drive seems to handle it OK.


If you're interested in participating in this experiment, please (a) 
check out the HamSci web page; (b) check the ttps://github.com/TAPR in a 
day or two to grab the software and docs; and (c) feel free to contact 
me directly with any questions.


73,
John N8UR
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Re: [time-nuts] Anderson PowerPole (was Charles Wenzel GPSDO)

[John Ackermann N8UR]

For what it's worth, I use PowerPoles extensively -- I use them for all 
my 12V distribution on ham gear as well as time-nuts stuff.  One great 
advantage of the genderless design is that you can use extension cables, 
breakout boxes, and other tools to solve lots of problems.


But they do lack as a chassis-mount connector.  I was looking for 
something inexpensive and reliable for 12V power on some rack enclosures 
I was building, and came upon a series of connectors that I really 
liked.  They are Conxall/Switchcraft "Mini-Con-X" series, available in a 
bunch of configurations from 2 to 8 or so pins.  I use a 2-pin version 
with solder-cup connectors that take up to 16 gauge wire.  The chassis 
version mounts in a 0.61 inch hole.


They're not throw-away cheap, but not unreasonable: the chassis 
connector (Conxall/Switchcraft 7382-2PG-300, DigiKey SC2130-ND) is $4.32 
quantity 1, and the matching in-line connector (Conxall/Switchcraft 
6382-2SG-3DC, DigiKey SC1893-ND) is $7.06 quantity 1.  I'm standardizing 
on these for any 12V project that goes into a box.  (If I do anything 
with 24V, I'll probably use a 3 or 4 pin version to avoid mis-plugging 
across the voltages.)


John


On 06/22/2017 01:45 PM, Brandon Graham wrote:

Having followed Time nuts for a bit, I guess I'll finally chime in.

For the PPs, it's like all other things, knowing the goods and bads.  I've
been using PPs for years, starting with RC Warship Combat (Battleships that
shoot and sink each other, so lots of interchangeable parts), and have seen
some of the other hobby connectors in use.  The hermaphroditic nature of
PPs are useful because you don't have to follow a standard as you can see
the polarity. Tamiya connectors from RC to Ham radio had a different
standard of opposite polarity with the same gender, allowing them to be
connected and blow equipment.  If you are using a lot of PPs (We've gone
through several hundred at this point) you don't create a mismatch of male
vs female connectors in your stock.  The double edge is that you can
connect things that shouldn't be connected if you are not careful.

The silver plated PPs also hold up better in wet environments.  PPs are
bulkier than some other hobby connectors, but for a connector that is
connected and disconnected frequently, the PPs work very well.

A safety factor the PPs have is that all contacts are covered.  There is no
exposed metal that could lead to a short. They have a audible and tactile
click when they are connected.  They can also be oriented in ways to
prevent plugging different voltages together.  They can also be very useful
in making large "bus" connectors, but are horribly bulky if something
smaller would do.

I'm not always a fan of chassis PPs on equipment (K3), and a short pigtale
from the equipment or a captive connector like the Molex is preferred to
then go to PP's. A command strip or other attachment on the equipment with
the power cable held to prevent disconnecting alleviates unplugging it
however.

My experience.
Brandon
W0GPR (ex-KB3IGC)

On Thu, Jun 22, 2017 at 11:25 AM, Richard (Rick) Karlquist <
rich...@karlquist.com> wrote:


No one has brought up the issue of hermaphrodicity, so
I will.  Only PP's are hermaphroditic.  Why does this
matter?  It matters in the case of a battery.  A battery
is both a power source and a power sink.  In the PP
system, you can make a 3 way connection between a
power source, a power sink, and a battery, where
the battery float charges on the 12V bus it is connected
to.  Non-hermaphroditic connector schemes do not allow
a 3 way connection.  Attempting to do a work around
would require fabricating a special 3 way harness,
which would not be idiot proof.

This is the fundamental reason for using PP's.

If you never use batteries, then all the other
gendered connector schemes are fair game.

As far as connectors pulling out is concerned:
use a cable clamp to strain relieve the connection.

Rick N6RK

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Re: [time-nuts] poor-man's oven

[John Ackermann N8UR]

We did this years ago on a 430 MHz data radio with an utterly uncompensated 
crystal that would drift through the passband.  After building our own for a 
while, we discovered that Yaesu had something even better available through 
their replacement parts shop -- a spring clip with PTC that snapped tightly 
over the crystal case.  I never did any formal measurements, but it did improve 
stability quite a bit for radios that were sitting in uncontrolled environments.

John

On Jun 4, 2017, 8:18 AM, at 8:18 AM, jimlux  wrote:
>I recall some years ago folks were talking about putting a PTC 
>thermistor on the TCXO of a FlexRadio SDR1000 to stabilize the
>frequency 
>as a sort of poor-man's OCXO.
>It's also referenced at
>http://www.setileague.org/askdr/xtaloven.htm
>where he says "order of magnitude improvement" with no numbers (from 1%
>
>to 0.1% or from 1 ppb to 0.1 ppb?)
>
>I wonder how well that actually works.
>
>Say you bought an inexpensive (perhaps non TC) XO and an equally 
>inexpensive thermistor, glued on on the other, hooked em both up to 3.3
>
>or 5V.
>
>Yeah, there's issues with room air blowing on it, and tolerances in
>both 
>the XO and thermistor, so your absolute frequency accuracy may not be
>so 
>hot. But what sort of medium to long term performance can one expect.
>
>I did some searches, because I'm sure we've discussed this before, but
>I 
>couldn't find it.  There was some stuff from Oct 2007, but that was in 
>the context of a more complex circuit, and the thermistor was the 
>sensor. (discussions of TE devices too)
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[time-nuts] Administrivia: febo.com SSL certificate

[John Ackermann N8UR]

If your browser has been throwing security warnings or errors when you 
try to access the web server at febo.com (for example, the list 
archives), that problem should now be fixed.


I was using an SSL certificate issued by StartSSL, a company that has 
sort of shot themselves in the foot due to their ownership structure and 
lack of transparency.  A few months ago the major browser vendors have 
stopped recognizing certs issued by StartSSL, and their browsers now 
give warnings when they encounter a StartSSL cert.


There's no evidence that my certificate was vulnerable or was ever 
compromised, but I've now changed over to certificates from a 
widely-supported group called LetsEncrypt, and you shouldn't see any 
further security warnings.


Thanks,
John
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Re: [time-nuts] Re. DIY atomic "resonator"

[John Ackermann N8UR]

I investigated police radar stuff a long time ago, and for a while had 
an old X band unit shaped just like a searchlight, with analog meter. 
What I learned then was that even on the newer units, the tuning fork 
was specified to provide an independent means to verify the accuracy of 
the unit in the field.


I also remember hearing that the radar sales reps had a special gift 
they would hand out to friends: a tuning fork marked "60 MPH" but that 
rang at a lower frequency, so you could use it to "calibrate" the unit 
to read higher than actual.  I heard that it was popular among the 
speed-trap crowd.


On 04/12/2017 09:25 AM, jimlux wrote:

On 4/11/17 11:09 AM, Mark Sims wrote:

Apparently fluorescent tubes continuously emit a lot of other
microwave signals.  I once built a  homodyne doppler "speed" radar kit
(used a coffee can for the antenna).  The way you calibrated it was to
point it at a florescent tube and and adjust the reading to a specific
value.

--



That's not because the tube is emitting..  It's a target reflector
turning on and off at twice line frequency.
In most homodyne radars, you filter out the DC (the reflections from
stuff that's not moving), so anything that pulses on and off creates
nice output.

At 10.525 GHz, the Doppler is about 70 Hz/ (m/sec), 31 Hz/(mi/hr)

at 24GHz, 160 and 71 Hz, respectively

Most simple speed guns just have an audio frequency counter on the
output of the mixer diode(s).  Older units use a Gunn oscillator, newer
ones use a DRO.  Some have a pair of detectors so you can distinguish
motion towards and away.

The old "calibrate with a tuning fork" for police radar wasn't
calibrating the RF frequency (a 1000 ppm change of the gunn oscillator
isn't a big deal.. this is a "3%" kind of measurement) - it was
calibrating the audio frequency counter, which, in very early units,
used an RC timebase. (or an actual analog meter reading) I cannot
imagine a crystal oscillator bad enough that a tuning fork  would be
better.  - if XO based speed guns were checked with a tuning fork it's
for one of two reasons:
1) the purchasing requirement said "A tuning fork for calibration shall
be provided" (based on an older design)
2) it provides a "functional test" and you don't really care what the
frequency is, as long as it lights up anything reasonable

Homodyne/Doppler radars are fun
(http://home.earthlink.net/~w6rmk/radar10g.htm) and can form the basis
of a business that saves lives
(https://www.nasa.gov/jpl/finder-search-and-rescue-technology-helped-save-lives-in-nepal)


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Re: [time-nuts] The ultraAtomic clock for home

[John Ackermann N8UR]

Is there any way to derive carrier phase from these chips?  Or to get raw 
modulation data that might make it usable as the front end to one of PaulS's 
de-PSKers?

On Apr 7, 2017, 1:04 PM, at 1:04 PM, Tom Van Baak  wrote:
>> Very good catch it is *not* the cme8000 chip. Thats a classic am
>receiver.
>> It is the everset chip. Sorry for mis-leading.
>
>Hi Paul,
>
>I can confirm (from talking with the guys backing it) that, yes, it's
>the EverSet ES100, in die form (CoB). I believe you and I have both
>used the early Xtendwave dev kits with the ES100 as SMT part. It's nice
>to see the chip still lives and finally made it to a product!
>
>
>I uploaded more ultrAtomic info and tear-down photos:
>
>http://leapsecond.com/pages/ultratomic/
>
>I encourage those of you who just bought these clocks to do some
>experiments. The obvious ones are:
>
>1) See how long it takes to acquire the correct time, at all sorts of
>different and difficult environments, compared to the traditional WWVB
>clocks. Check for off-by-one second, or minute, or hour errors.
>
>2) See how accurate they really are. For clocks like this I use a
>variety of piezo sensors (feel the tick), acoustic sensors (hear the
>tick), optical sensors (see the tick), and mostly electrical sensors.
>Some of these are passive (non-destructive) timings and good enough.
>Others require some level of disassembly but are more precise. For a
>stepper motor clock it's easy to tap onto the coil connections and get
>a sharp pulse every second or two. Then use a time interval counter, or
>picPET, or TICC, or PC-based PPS-capture to collect readings. Note the
>signal level is usually low power and below typical TTL levels, and
>they do NOT drive 50R!
>
>
>If all goes well, we can soon talk about a time-nuts special where we
>get someone to make a timing board or disciplined timing board based on
>the ES100 chip. The bad news is that at the same price it would be like
>a million times worse than GPS. The good news is that lots of
>applications need only ms level timing; there are places where WWVB is
>receivable and GNSS is not; and then there's the redundancy and
>low-power factor.
>
>/tvb
>
>- Original Message - 
>From: "paul swed" 
>To: "Discussion of precise time and frequency measurement"
>
>Sent: Friday, April 07, 2017 5:08 AM
>Subject: Re: [time-nuts] The ultraAtomic clock for home
>
>
>Tom
>Very good catch it is *not* the cme8000 chip. Thats a classic am
>receiver.
>It is the everset chip. Sorry for mis-leading.
>Regards
>Paul
>WB8TSL
>
>
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Re: [time-nuts] ADEV query Timelab and TICC

[John Ackermann N8UR]

I noticed with the TICC that the very high peak voltage on the 5061, 5065, etc. 
PPS causes trigger errors.  Putting a 50 ohm load at the TICC channel input 
helped a lot, or an attenuator might even be better.

These HP units have a very short pulse width that peaks at something like 20v 
into a high impedance.  It doesn't​ seem to hurt the TICC input circuit, but 
causes ringing that results in perceived jitter.  Knocking that down to TTL 
level solves the problem.

On Mar 20, 2017, 12:01 PM, at 12:01 PM, timeok  wrote:
>
>   All,
>the similar problem I have verified using the HP5065A and HP5061B 1PPS
>output, the dividers are pratically unusable for ADEV measurements. The
>5/10MHz output of the same instruments using the TAPR divider are ok,
>so these dividers have some spike noise problems. It can be seen even
>using other TIC as The HP53132A.
>   Luciano
>   www.timeok.it
>
>
>   Da "time-nuts" time-nuts-boun...@febo.com
>A "Discussion of precise time and frequency measurement"
>time-nuts@febo.com
>   Cc
>   Data Sun, 19 Mar 2017 20:03:29 -0700
>   Oggetto Re: [time-nuts] ADEV query Timelab and TICC
>> I have sent a couple of files to Tom. They were taken simultaneously
>from
>> an LTE Lite - one from the PPS and one from a PicDiv dividing the
>10MHz to
>> 1Hz. The glitches were on the PPS trace, but not on the PicDiv trace,
>so
>   > I'm fairly confident the TICC was working correctly.
>   >
>   > Orin.
>
>   Hi Orin,
>
>Thanks for the raw data. It's very nice (2 hours 16 minutes = 8219
>points). Everything looks fine with the exception of 8 glitches. These
>are sometimes obvious jumps in phase, which cause massive spikes in
>frequency. Two plots attached.
>
>Almost every data point is within a few ns of each other. This is good.
>The standard deviation is a fraction of 1 ns. But once in a while there
>is a relatively massive phase jump. This is bad. Interestingly these 8
>phase jumps all appear to be about 25 ns or a multiple of 25 ns in
>magnitude. The full list is (ns units):
>
>   24.575
>   24.724
>   24.831
>   25.047
>   25.087
>   25.549
>   25.589
>   49.623
>
>25 * N ns is not random. So I think this is not a Windows problem, not
>a USB problem, not a TimeLab problem, not a TICC problem either.
>
>It makes me wonder if this is a LTE-Lite problem. If Said or Keith from
>Jackson Labs is around -- is there anything on the LTE-Lite board
>that's close to 20 or 40 or 80 MHz? At this point I kind of trust
>Orin's data and I kind of trust the TICC. So when I see monster 25 ns
>phase jumps it makes me think there's a problem with the GSPDO board
>itself.
>
>(Please realize that only on time-nuts may we can use the words
>"monster" and "25 ns" in the same sentence; the rest of the world has
>larger problems)
>
>   /tvb
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Re: [time-nuts] ADEV query Timelab and TICC

[John Ackermann N8UR]

I saw a similar higher-than-expected ADEV from another user who was measuring 
GPSDO PPS vs. 10 MHz from the same GPSDO.  Using a T2-Mini  from the 10 MHz 
yields the expected results.

I suspect that the GPSDO PPS in that unit is derived from GPS PPS rather than 
the OCXO, and thus is noisier in the short term than might otherwise be 
expected.

John

PS -- we just got into our new house and still don't have internet access, so 
I've not been on line as much as usual.  another few days and things should!D 
be getting back to normal.



On Mar 19, 2017, 8:01 PM, at 8:01 PM, Orin Eman  wrote:
>On Sun, Mar 19, 2017 at 3:00 PM, Tom Van Baak 
>wrote:
>
>> > I've seen similar with my TICC when observing a PPS - can't
>remember
>> > whether the PPS was from the Thunderbolt or LTE Lite.
>> >
>> > There was a distinct glitch on the frequency plot when it happened
>and it
>> > was pretty easy in timelab to expand the trace around the glitch to
>take
>> a
>> > better look.
>>
>> Orin -- Thanks for that report. If you still have the TIM file, can
>you
>> send it to me?
>>
>
>
>I have sent a couple of files to Tom.  They were taken simultaneously
>from
>an LTE Lite - one from the PPS and one from a PicDiv dividing the 10MHz
>to
>1Hz.  The glitches were on the PPS trace, but not on the PicDiv trace,
>so
>I'm fairly confident the TICC was working correctly.
>
>Orin.
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Re: [time-nuts] My TICC came in the mail yesterday

[John Ackermann N8UR]

Hi Andrew --

There seems to be more than a little magic involved in getting sane 
three-corner measurements.  I've gotten best results when the run is 
long enough to have many data points per tau, and also that results when 
you're noise limited tend to go imaginary.  Finally, I think things work 
best when the three sources have similar noise processes, e.g., looking 
at 3x OCXO or 3x Rb or whatever.


I'd love any of the experts to jump in on this, as I've not done much 
beyond basic experiments, and I don't have the maths to comprehend the 
subtleties.


John

On 02/24/2017 12:59 PM, Andrew Rodland wrote:

Which means, after a bit of scrounging for some BNC to SMA adapters, I
have some plots worth using (more or less) of my clock!

Background info: my clock's main purpose is to be a GPS-disciplined
NTP server on an Arduino Due clone board. As such, accuracy beyond
tens to hundreds of microseconds isn't really relevant. But for purely
time-nut reasons, it has an Rb oscillator (cheap surplus X72), and for
similar reasons it has a PPS output generated by the CPU timer. I
didn't hack the Due apart to replace the crystal, so the CPU clock
(84MHz) is asynchronous from the Rb, which has some limitations, but
also introduces a nice little bit of dither

The TICC is set up with 10MHz from a Spectracom NetClock, chA from a
(probably insufficiently thermally stabilized) LTE-Lite, and chB from
my clock. Output is in Timelab mode.

A representative bit of the phase plot: http://i.imgur.com/cRXv9ia.png

You can see all the quantization noise on my clock, but also that in
the ~100s region, it does better than the LTE-Lite. You can also see
the nice smooth (at short time) plot of the LTE-Lite which gives me
some good faith in the TICC.

ADEV plot so far: http://i.imgur.com/DLb15rt.png

Timelab loses the thread a little bit and comes up with negative
computed deviations for my clock for some tau. Not sure how much of
that is due to instrument limitations, and how much is due to the
noise being not-really-independent, since all three clocks are GPS
receivers, with rather nearby antennas. Still, more than I've ever
seen before!

Andrew
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Re: [time-nuts] Trimble "UCCM" GPSDO adevs

[John Ackermann N8UR]

This is very, very cool, Mark.  I've been concerned for a long time that 
people take way too seriously what you properly call "bogo-ADEV" that's 
self-generated from the GPSDO.  Integrating a counter that compares 
against an external source is a huge win.


But I want to remind everyone that as neat as the TICC is, like any time 
interval counter it still has limited performance for short-term ADEV. 
The ADEV floor is typically a bit under 1x10e-10 at one second, and goes 
down at a slope of -1 (so, a bit under 1x10e-13 at 1000 seconds averaging).


If you're comparing a pair of decent sources, results at measurement tau 
of less than at least several hundred seconds are likely showing counter 
jitter, not real performance.  It's important always to keep that in mind.


John


On 02/23/2017 05:27 PM, Mark Sims wrote:

I just added the capability of Heather to monitor and control a GPS device while 
simultaneously calculating ADEVs from an external time interval counter like the TAPR 
TICC  (it can also work with the time interval analyzer only).  This mode lets Heather 
calculate true adevs instead of "bogo-adevs" derived from the GPSDO 
self-reported control loop statistics.

As a test.  I connected Heather to a Trimble "UUCM" GPSDO and a TICC.  The TICC 
channel A is the UCCM and channel B is a Oscilloquartz Star-4 GPSDO.  The TICC reference is 
a ERC-130 rubidium (uses an LPRO-101.  Attached is a screen dump of a 12 hour run.  The UUCM 
beats the Star-4 at tau<20 seconds.

There are a few variants of the UCCM receivers out there... one by Symmetricom and at least two (UCCM and UCCM-P) by 
Trimble.  They run off of 6VDC.   Performance is not too shabby for a small $70-$120 GPSDO.   Search Ebay for 
"Trimble 65256",  "Trimble GPSDO", or "Symmetricom GPSDO".   Be aware that there are 
sellers sending units that were damaged in salvage.   I'd probably go with a "tested" unit.



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Re: [time-nuts] TTimelab question

[John Ackermann N8UR]

I really like the setup that Mark is describing.  As to TAPR's plans, 
we've found that enclosures are a challenge -- metalwork is pretty 
expensive unless you get significant volume, and in our niche market, 
that's hard to do.


But I am hoping to find an inexpensive clamshell-type enclosure with 
flat front and rear panels, and then do up designs (perhaps with Front 
Panel Express) for those panels.  That can be done at a reasonable cost, 
and at a minimum we can make design files available so people can order 
their own panels.


For my own use, I'm also going to do a couple of 2U rack enclosures -- 
one to hold two TICCs operating independently, and another for the 
"megaTICC" -- four units slaved together to make an 8 channel counter, 
with a Raspberry Pi controller along the line of what Mark described. 
(In multi-board mode, each TICC outputs on its own USB line, so the 
RPi's main purpose is to deal with the 8 channels of data from 4 USB 
connections.)


I'll make the design files for those enclosures available as well, but 
it may be a while as my entire lab is now packed up as we are in the 
final stages of moving from Atlanta back to Dayton.


Also, in a day or three I'll be announcing a simple project that sprung 
out of the TICC assembly and testing process that some of you might find 
useful.  We're still finalizing details on that.


John

On 02/21/2017 11:45 PM, Mark Sims wrote:

I doubt that it is something TAPR would do.   Building complete systems gets 
into all sorts of issues (mainly regulatory).   But it is easy enough to build. 
  They sell a nice case that the RPI3 and touchscreen mounts in.  The 
PI+touchscreen+case sells for around $110.   The TICC(s) connect to it via USB.

There are also some Win10 tablets with 1024x600 touch screens that sell for 
around $60 (apparently Microsoft doesn't charge manufacturers for Win10 on 
tablets with small/low res screens).

I  am thinking about laying out a front-end board for the TICC.  It would have 
some switchable (relay?) 50 ohm input terminators,  switchable PICDIV dividers 
for PPS/1MHz/5MHz/10MHz/15MHz (or 2.5 MHz)  inputs,  footprints for a decent 
reference oscillator (MV89/8663/DIP/etc), and a 12V to 5V (3A?) power converter 
for the  TICC and PI... most of the better surplus oscillators run off of 12V.  
Also maybe add a data multiplexer for combining the outputs of two TICC boards 
into one data stream (but Heather could do that in software).  John has some 
ideas for a similar board.

-


  Wow!  If you can persuade John and TAPR to produce that, I would be there

with my chequebook before the ink had dried on the web-page! :-)
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[time-nuts] TICC shipments

[John Ackermann N8UR]

Hi All --

The production batch of TICCs has arrived at TAPR and the first 
shipments to customers are going out today.  It will probably take 
another few days to get them all sent -- there are nearly 100 units 
going out the door!


As previously mentioned, the TICCs have been loaded with software and 
tested, so they should be "plug and play" when they arrive.


I've been working on the user guide, and while it's still a bit rough, I 
think it's fairly complete.  You can download it from


https://github.com/TAPR/TICC/tree/master/docs/TAPR%20TICC%20User%20Manual.pdf

The installed software version is "20170108.1" Since then, I've 
implemented a couple of new features, including semi-tested code for 
slaving multiple TICCs into a 4 or more channel counter (semi-tested 
because I still only have one unit!), and a polling capability in 
addition to the normal "talker" mode.


The updated source code is available at

https://github.com/TAPR/TICC/tree/master/TICC

If you don't want to install the Arduino IDE and build/upload the code 
yourself,


https://github.com/TAPR/TICC/tree/master/binaries

contains a compiled version, as well as a simple Windows tool to upload 
it into the Arduino.  The User Manual has instructions on how to do the 
upload.


Enjoy!

John
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[time-nuts] TICC update

[John Ackermann N8UR]

Our contract manufacturer has started loading software and testing the 
TICC systems (and so far, they all work!), and should ship the 
production run to TAPR by the end of the week.  We'll start shipping 
them to customers shortly after they arrive at the office.


We still have units available for order:
http://tapr.org/kits_ticc.html

John
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[time-nuts] What interrupts aging?

[John Ackermann N8UR]

We know of OCXO that have been continuously running for years and have 
exceptional aging, supposedly as a result.


What does it take to interrupt that? A momentary loss of power?  The 
oven cooling down?  Some long period of off-time?  Or, once the 
oscillator has baked in will it return to that low aging once it has 
been powered up and thermally stabilized?


John
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[time-nuts] Dropbox is cool, but...

[John Ackermann N8UR]

So I was clever and decided to log some PPS data to a folder within my 
"Dropbox" folder.  Strange results followed... the whole system just 
bogged down, and even fairly slow serial data dropped characters.


It turns out that the culprit was the Dropbox daemon continuously trying 
to sync the file as it changed every second.  It didn't manifest as CPU 
overload or anything obvious; the problem was apparently thrashing in 
the I/O system.  Once I started dumping the data to a "normal" 
directory, the problem went away.  (This was on Linux, by the way).


So, a lesson learned -- don't stream unbuffered data, even at a low 
rate, into a sync'd folder!


John
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[time-nuts] Autodesk Eagle -- maybe they're listening

[John Ackermann N8UR]

Autodesk just sent a follow-up to my "new price model unacceptable" 
complaint a few days ago.  It looks like they are going to upgrade the 
"Standard" subscription ($100/year) to support 4 layer boards up to 160 
cm2, which I think matches the current standard version capabilities. 
Here's a thread from the Autodesk forum:


http://forums.autodesk.com/t5/eagle-forum/a-path-forward-for-the-make-license-a-step-up-for-standard/td-p/6823182

This is effective with the next release, which is supposed to be out in 
a couple of weeks.  (In the meantime, I've made sure to download every 
flavor of installer for version 7.7.0, just in case...)



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Re: [time-nuts] OT: Eagle PC CAD now Autodesk, $500/year

[John Ackermann N8UR]

The .INF file seems just to be a text description, and the non-versioned 
.ext/.zip/.run file  file is a link to the file one with the version number.  
So either one will get you the same installer, and the .INF file isn't needed.

Sent from BlueMail ​

On Jan 21, 2017, 9:45 PM, at 9:45 PM, "Richard (Rick) Karlquist" 
 wrote:
>I downloaded the following:
>
>eagle-win64.exe
>eagle-win64-7.7.0.exe
>eagle-win64-7.7.0.exe.INF
>
>What is the difference between these files in terms of installing this 
>version?  Which file do I run?  Do I need the other ones to go along
>with it?
>
>(Similarly, for LINUX, there is the same set of files, except
>substitute "run" for "exe")
>
>Rick N6RK
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[time-nuts] Plug -- source for soldering equipment

[John Ackermann N8UR]

Since quite a few of the folks on the list love the smell of solder in 
the morning, I thought I'd pass along a supplier of new and refurbished 
soldering stuff that I've had really good luck with:

Bruce Sander at EAE Sales -- https://www.eaesales.com/ in Grabill, Indiana.

I encountered EAE a long time ago at the Dayton Hamvention flea market 
and over the years have bought a couple of Weller soldering stations, 
pencils, tips and accessories from them and been very happy.


I was prompted to write this note because last week Bruce really helped 
me out with a "we trust you" swap for a failed set of heated tweezers. 
I don't have any relationship with EAE other than as a satisfied customer.


John
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Re: [time-nuts] TICC update?

[John Ackermann N8UR]

⁣Hi Scott --

We received the first-unit sample a couple of weeks ago and it successfully 
passed all tests, so we gave the go-ahead to do the production build.

We've also sent the Contract Manufacturer the final software versions to be 
loaded to the Arduino as well as a set of test oscillators for unit testing.  
(The production code is in master at https://github.com/TAPR/TICC)

My project for this coming weekend is to get the user documentation ready; it's 
also at GitHub.

I don't know precisely where the CM is in the process right now, but we're 
still looking for delivery to TAPR by early February.

You can still order:  http://tapr.org/kits_ticc.html

John



On Jan 16, 2017, 10:17 PM, at 10:17 PM, Scott Newell 
 wrote:
>I see that my credit card has been charged. Is that a hint that the 
>TICC project is moving along? Should I start gathering up cables and 
>SMA adapters?
>
>-- 
>newell  N5TNL
>
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Re: [time-nuts] Tom's PICDiv?

[John Ackermann N8UR]

Sorry, I missed the "complete unit" part... the TAPR products do require 
some soldering.  The TADD-2 does have a case available if that helps.


John

On 1/5/2017 8:21 AM, John Ackermann N8UR wrote:

Hi Bob --

TAPR has two boards that provide life support for Tom's PICDiv chips:

The "TADD-2" is a six-channel divider allowing each channel to have its
rate independently set from a common source:
https://www.tapr.org/kits_tadd-2.html

The "T2-Mini" is a tiny board that provides a single channel of PPS (or
whatever you want) from an RF input:
https://www.tapr.org/kits_t2-mini.html

John



On 1/5/2017 12:34 AM, Bob Stewart wrote:

Hi all,
I was wondering if anyone makes a nice, complete unit from one of
Tom's PICDivs; preferably with an external 10MHz input, a 10MHz output
and a 1PPS output?  It would be nice if it also accepted a 1PPS in to
sync the PIC's output to an external 1PPS source, but that's not a
necessity.  I've got something kludged together here that I can drive
from my Cs standard for testing, but I was hoping for something a bit
more purpose made if anyone makes one?  Not looking for a kit or just
a board, nor do I have any interest in making/marketing such a unit.

Bob -
AE6RV.com

GFS GPSDO list:
groups.yahoo.com/neo/groups/GFS-GPSDOs/info
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Re: [time-nuts] Tom's PICDiv?

[John Ackermann N8UR]

Hi Bob --

TAPR has two boards that provide life support for Tom's PICDiv chips:

The "TADD-2" is a six-channel divider allowing each channel to have its 
rate independently set from a common source:

https://www.tapr.org/kits_tadd-2.html

The "T2-Mini" is a tiny board that provides a single channel of PPS (or 
whatever you want) from an RF input:

https://www.tapr.org/kits_t2-mini.html

John



On 1/5/2017 12:34 AM, Bob Stewart wrote:

Hi all,
I was wondering if anyone makes a nice, complete unit from one of Tom's 
PICDivs; preferably with an external 10MHz input, a 10MHz output and a 1PPS 
output?  It would be nice if it also accepted a 1PPS in to sync the PIC's 
output to an external 1PPS source, but that's not a necessity.  I've got 
something kludged together here that I can drive from my Cs standard for 
testing, but I was hoping for something a bit more purpose made if anyone makes 
one?  Not looking for a kit or just a board, nor do I have any interest in 
making/marketing such a unit.

Bob -
AE6RV.com

GFS GPSDO list:
groups.yahoo.com/neo/groups/GFS-GPSDOs/info
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[time-nuts] Update on TNS-BUF and TICC projects

[John Ackermann N8UR]

Happy New Year, Time-Nuts!

TAPR received the production run of TNS-BUF boards, and the engineering 
sample of the TICC, from our contract manufacturer last week.


Both boards are nicely built and work as intended.

TNS-BUF boards will be shipping soon to those who ordered; some may 
already have gone out.


We will pull the trigger on the TICC production run by the end of the 
week, after doing a bit more preliminary work.  Delivery is still 
scheduled for early February.


Other news on the TICC front is that help from fellow time-nut Dave 
McQuate has yielded the last major module for the TICC software, so we 
will be able to ship the boards with fully-functional (though not 
guaranteed bug-free!) software loaded.  Thanks, Dave!


John
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Re: [time-nuts] 1PPS users?

[John Ackermann N8UR]

For amateur use, PPS comparison requires less equipment and can be more 
accurate than trying to measure RF rates like 10 MHz.


When comparing two PPS signals, phase slips are very infrequent so you 
can observe drift rate over minutes/hours/days with an oscilloscope or 
simple time interval counter to get much better resolution than most 
frequency counters can provide.  (Of course, a GPS works as well for 
this as a GPSDO, albeit with more short term jitter.)


John

On 12/18/2016 08:33 PM, Bob Stewart wrote:

Hi Jim,
Thanks Jim,

So, what I'm seeing so far, assuming I'm interpreting it correctly, is big 
budget commercial and government applications, generally clustering around 
time-controlled multiplexing, as well as the niche that is the space industry.  
Then there's the hobbyist, such as Eric who wants to control a Fedchenko clock, 
or similar type of application, such as whatever sort of spread spectrum that 
ham radio may morph into, or perhaps the low S/N EME guys.  Any others?
Bob

   From: jimlux 
  To: time-nuts@febo.com
  Sent: Sunday, December 18, 2016 6:56 PM
  Subject: Re: [time-nuts] 1PPS users?

On 12/18/16 3:16 PM, Bob Stewart wrote:

One thing I've never really understood is who actually uses the high-quality 
1PPS output from a GPSDO.  I have spent a lot of time, effort, and money on 
developing my GPSDO without a whole of thought to the user base.  It was just a 
quest for the best result I could obtain with a particular technology.  The 
frequency standard users was a no brainer.  Everyone who wants a frequency 
standard eventually understands they need to get a GPSDO, or an Rb, or a Cs.  
And that's all I thought I had: a good frequency standard.  And then Tom 
prodded me a bit and showed me the shortcomings of what I was doing, and I did 
something about it.  So, if an NTP user can get his time fix directly from a 
noisy receiver, who actually needs a time-accurate, low jitter 1PPS pulse?


Anyone who needs to trigger events at a precise time or log the
occurrence of an event uses the 1 pps - the serial port (or other
interface) gives you the "at the tone the time will be" message, and the
edge of the 1pps is the "tone".


I've got several systems flying in space (or soon to fly in space) that
use the 1pps from GPS to calibrate their internal clocks and/or to
provide an absolute time reference (along with the aforesaid time message).

For example, one needs to have your carrier frequency within a certain
tolerance for communications with the ground stations: you can either
fly a precision oscillator with an oven (big, heavy, high power) or you
can measure a not-so-precision oscillator (small, cheap, low power)
against a 1pps, and adjust your frequency that way.

I grant you that this is really more like *building* a GPSDO than
*using* a GPSDO.

I've used the 1pps from a GPSDO as a common trigger to synchronize
timing and timestamping for separate systems.



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

[John Ackermann N8UR]

That points out a key difference in the PCB house pricing models: 
ExpressPCB and the Advanced Circuits $33 prototype are flat fee up to a 
size limit (for Advanced Circuits 4 x 6 inches) while others go by the 
square inch -- OSH Park is $5/in2 for three copies of two layer, and 
$10/in2 for three of four layer.


So for small boards, OSH Park is great but for larger boards, the price 
difference reduces (a 4 x 6 board ends up being just about the same 
price as Advanced Circuits).  And if you can stand the slower 
turnaround, the Chinese board houses can't be beat for any size.


John

On 12/9/2016 3:18 PM, Bob Stewart wrote:

I built my first set of boards with ExpressPCB, but they get expensive quickly if you 
want to make something that's not in their special form factor.  I use KICAD and 
OshPark.com to make my boards (there are other board makers).  I just ordered some boards 
that are .7" x .63" that cost $8.40 for 12.  You buy in multiples of 3, so that 
was actually $2.10 for a set of 3 times 4 sets.  Using surface mount, I was able to put 
an SOIC-14, an SOIC-16, an SOT23-5, three 0805 caps, a 3 pin header, and a 5 pad 
connector on the board.  Something like that would be wastefully expensive on ExpressPCB.

Bob


   From: BIll Ezell 
  To: time-nuts@febo.com
  Sent: Friday, December 9, 2016 1:58 PM
  Subject: [time-nuts] OT: ExpressPCB (cross-post from volts-nuts)

Sorry if I'm behind the times, just did a new project that required a
pcb, and ExpressPCB is my go-to vendor for one-off boards. I just
noticed they now provide the low-cost boards (fixed size, 3x5, quantity
3) that I've always ordered with silk screen and solder mask for $71. I
got my latest boards that way and they're beautiful. No relationship to
them, just a happy customer. You can still get the barebones boards for
$51. The hack I used to use was to put the component id and such on the
top copper layer as tiny text, but that was a bit of a pain for layout.
(Oops, can't put that label there, it's copper and there's a trace there
also) Really nice to be able to get real boards, even if it does end up
being ~$23/board.


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Re: [time-nuts] TICC Timestamping / Time Interval Counter -- Available to Order

[John Ackermann N8UR]

Hi Luciano --

The expanded-channels scenario would use one TICC/Arduino pair for each 
set of channels.  It would require much redesign to stack multiple TICCs 
on a single Arduino, and I don't think one board would have the power to 
handle it.


What I envisioned would be a set of TICC/Arduinos each putting their 
data on USB, and then something like a RPi receiving the multiple USB 
data streams and serving as a control unit that might multiplex the data 
onto a single ethernet stream, or do processing/storage itself.


At this point, the TICC board includes the connections to allow multiple 
boards to be synchronized but we haven't implemented the full system yet 
-- in part because until now there are only 4 working TICCs in the 
world, and they are in 3 locations!


John


On 12/8/2016 8:09 AM, timeok wrote:


Hi John,
a question: In the draft operating manual is write is possible to use 2, 4 
,6 etc. input using multiple (1,2,3) TICC.
How are connected the extra TICC boards?
Is it possible a single Arduino drive multiple boards or each board is 
connected to an Arduino processor?
thanks,
Luciano
www.timeok.it


From "time-nuts" time-nuts-boun...@febo.com
To "Discussion of precise time and frequency measurement" time-nuts@febo.com
Cc
Date Wed, 7 Dec 2016 14:45:17 -0500
Subject [time-nuts] TICC Timestamping / Time Interval Counter -- Available 
to Order
I'm happy to report that TAPR is now accepting orders for the TICC
timestamping / time interval counter. We've placed an order with the
contract manufacturer and expect to have finished product ready to ship
sometime in February. The TICC system will include the TICC shield
mounted on an Arduino Mega 2560 compatible processor, with TICC software
loaded. Each system will be tested for function before shipping.

As I mentioned in my original email, TAPR is going a bit out on a limb
to produce the TICC, and we have to make a significant up-front payment
to our contract manufacturer. So, early orders are very much appreciated
to help recover our cash flow.

The regular price will be $190 each for the TICC shield with Arduino
compatible processor,* but to encourage early orders, we're offering a
$10 discount for orders placed on or before December 21 -- that makes
the price $180 plus shipping.

You can order from: http://tapr.org/kits_ticc.html

Thanks!
John

* We will provide a Sainsmart version of the Arduino Mega 2560 R3. They
seem to be a reliable supplier and we used these boards for TICC
development.


 Forwarded Message 
Subject: [time-nuts] New Timestamping / Time Interval Counter: the TICC
Date: Wed, 23 Nov 2016 10:48:57 -0500
From: John Ackermann N8UR <j...@febo.com>

Counters with resolution below 1 nanosecond are difficult.
They require either outrageous clock speeds, or interpolators
that are typically a bunch of analog components mixed with black
magic and stirred by frequent calibration. The very best single-shot
resolution that's been commercially available is 20 picoseconds in
the Keysight 53230A and HP 5370A/B. My 5370B has an one-second
noise ADEV of about 4x10e-11.

With the help of some very talented friends, I've been working on a new
counter called the "TICC" with <60ps resolution and similar jitter,
based the Texas Instruments TDC7200 time-to-data-converter chip. The
noise ADEV is about 7x10e-11, not much worse than the 5370,
but here's the trick: the TICC is an Arduino shield (mounting a
Mega 2560 controller) that weighs a couple of ounces, requires
*no* calibration, and is powered from a USB cable!

The TICC is implemented as a two-channel timestamping counter. That
means it can measure or two low-frequency (e.g., pulse-per-second)
inputs against an external 10 MHz reference, or it can do a traditional
time interval measurement of input against the other. It can also
measure period, ratio, or any other function of two-channel timestamp
data. (And by the way -- multiple TICCs can be connected to yield 4,
6, 8, or more synchronized channels, though we haven't tested this
capability yet.)

I've attached a picture of the TICC prototype as well as an ADEV plot
of a 17+ day run of multiple measurements taken by two TICCs, and also
showing the TICC noise floor. The good news behind that plot is that
there are more than 6 million data points behind these results, and
there was not a single glitch or significant outlier among them.

There's more information available at http://febo.com/pages/TICC

The software is open source (BSD license) and is available at
https://github.com/TAPR/TICC -- the current version seems be reliable
but there are still features to add and a *lot* of cleanup to do; it's
current

Re: [time-nuts] Switching regulator replacement for 7805

[John Ackermann N8UR]

On 12/04/2016 04:34 PM, jimlux wrote:


Even for time-nuts, I suspect we're not looking to eke out the last
percent of efficiency from 96% to 97%, or handle wildly varying loads,
etc.  Nor are we usually looking for absolute minimum parts cost.


The little OCXO I used for testing goes from about 850ma cold to 200ma 
hot (at 5V) and I noticed a very different appearance of the spectrum as 
the current dropped -- at high current, the switching spurs were quite 
narrow, but as the current dropped (and particularly below some 
threshold I don't remember) the spurs widened out quite a bit.

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Re: [time-nuts] Switching regulator replacement for 7805

[John Ackermann N8UR]

That's a very good point... the design I'm testing the regulator in has 
a fair bit of C filtering, but no series L.


On 12/04/2016 02:45 PM, Chris Albertson wrote:

Surprisingly good as a drop-in replacement.

Question:  Suppose you are doing a new design and had space on the PCB for
one more small passive part.  I wonder how the performance of the switcher
with an LC filter compares with the 7805.Yes, I think this is fair.  It
is a trade off, It costs me one more inductor but I gain hugely reduced
power consumption and heat.

Or stated another way:  You have shown the noise difference for drop in to
existing circuit.  What about two roughly equivalent new design circuits?
How much to we pay in dollars and complexity to get equivalent noise?

Thanks a lot for this work.  Headed over to eBay right now

  (My application uses LiPo battery and needs to have stable voltage as the
battery drains but my current solution is noisyand those 78xx chips waste
far to much power. )

On Sun, Dec 4, 2016 at 10:50 AM, John Ackermann N8UR <j...@febo.com> wrote:


I found a cute little switching regulator that's a drop-in replacement for
an LM7805: http://www.ebay.com/itm/261243604047

I got a couple to play with, mainly to see how bad the noise would be.
Here are spectrum analyzer and PN shots comparing a cheap surplus OCXO when
driven by a regular 7805 and by the switching replacement.

The switching frequency is supposed to be 2 MHz but you can see that it's
more like 2.4 MHz.  Whether this performance is sufficient for any
application is up to you.  It sure runs a lot cooler than a 7805, though!

John




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Re: [time-nuts] Switching regulator replacement for 7805

[John Ackermann N8UR]

And Digikey does stock the Murata part, for about $4.30.  Why I couldn't 
find it when searching their site for switching regulators, I don't know.


John


On 12/04/2016 02:39 PM, John Ackermann N8UR wrote:

Thanks for that pointer!  When I searched Digikey, I wasn't able to find
anything that was in the 3-lead TO-220 case.  I will definitely check
out the Murata units, as I suspect they perform better than this one.

John

On 12/04/2016 02:01 PM, Adrian Godwin wrote:

Thanks for this. I've seen something similar from Murata :

http://uk.farnell.com/murata-power-solutions/oki-78sr-5-1-5-w36-c/converter-dc-dc-1-o-p-7-5w-1-5a/dp/2102101


Since they're a mainstream supplier of inductors they may have managed
better performance - it would be interesting to compare.


On Sun, Dec 4, 2016 at 6:50 PM, John Ackermann N8UR <j...@febo.com> wrote:


I found a cute little switching regulator that's a drop-in
replacement for
an LM7805: http://www.ebay.com/itm/261243604047

I got a couple to play with, mainly to see how bad the noise would be.
Here are spectrum analyzer and PN shots comparing a cheap surplus
OCXO when
driven by a regular 7805 and by the switching replacement.

The switching frequency is supposed to be 2 MHz but you can see that
it's
more like 2.4 MHz.  Whether this performance is sufficient for any
application is up to you.  It sure runs a lot cooler than a 7805,
though!

John




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Re: [time-nuts] Switching regulator replacement for 7805

[John Ackermann N8UR]

Thanks for that pointer!  When I searched Digikey, I wasn't able to find 
anything that was in the 3-lead TO-220 case.  I will definitely check 
out the Murata units, as I suspect they perform better than this one.


John

On 12/04/2016 02:01 PM, Adrian Godwin wrote:

Thanks for this. I've seen something similar from Murata :

http://uk.farnell.com/murata-power-solutions/oki-78sr-5-1-5-w36-c/converter-dc-dc-1-o-p-7-5w-1-5a/dp/2102101

Since they're a mainstream supplier of inductors they may have managed
better performance - it would be interesting to compare.


On Sun, Dec 4, 2016 at 6:50 PM, John Ackermann N8UR <j...@febo.com> wrote:


I found a cute little switching regulator that's a drop-in replacement for
an LM7805: http://www.ebay.com/itm/261243604047

I got a couple to play with, mainly to see how bad the noise would be.
Here are spectrum analyzer and PN shots comparing a cheap surplus OCXO when
driven by a regular 7805 and by the switching replacement.

The switching frequency is supposed to be 2 MHz but you can see that it's
more like 2.4 MHz.  Whether this performance is sufficient for any
application is up to you.  It sure runs a lot cooler than a 7805, though!

John




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Re: [time-nuts] New Timestamping / Time Interval Counter: the TICC

[John Ackermann N8UR]

Hi Bob --

It's certainly possible to synchronize the TICC timescale epoch to an 
external pulse at startup.  The external sync pulse would have to 
simultaneously reset (a) the picDIV and (b) the coarse (100us) counter 
in the Arduino. The signals to do that are available, so it's a 
worthwhile experiment.


I have to think through whether there are any other gotchas but I'm 
pretty sure that you would not get closer than a few hundred nanoseconds 
given how closely the picDIV can sync -- I think Tom specifies that it's 
within 4 clocks, or 400 ns.


(Now, syncing two TICCs to each other is a different matter because 
there we one unit is master and provides the coarse clock directly to 
the slave; if both units are run from the same 10 MHz clock they should 
align within one 10 MHz tick.)


John


On 11/27/2016 12:26 PM, Bob Camp wrote:

Hi

Ok, so the guess was fairly close :)

How about a connector to allow an external PPS to reset the internal 10 MHz 
divider? That way all
the data is “in sync� with the house standard. If I want to know that my 
GPSDO is +32.751 ns off from
the house standard, I just look at the data on a terminal program …

Or am I missing something really obvious (again)?

Bob


On Nov 27, 2016, at 10:04 AM, John Ackermann N8UR <j...@febo.com> wrote:

Good guess.  The 10 MHz reference drives all the logic on the board, and 
particularly the counter that maintains a local timescale in 100us increments; 
the TDC7200 interpolates between the 100us ticks to stamp incoming events on 
channel A and/or B with picosecond precision.  The stamps on both channels are 
referenced to the same local timescale.

Therefore, you can do a measurement of a PPS source against the 10 MHz 
reference and the resulting timestamp output can be processed by TimeLab or 
whatever into stability data (the requirement being that the software knows how 
to deal with timestamps that increment by the nominal measurement rate, e.g., 1 
second per measurement for PPS data).

So with PPS from GPSDO "A" on channel A the timestamp output after unwrapping 
will show the phase of A vs. 10 MHz.

You can add PPS from GPSDO "B" on channel B and the TICC will also output 
timestamps of B vs. the 10 MHz source.

If you want, you can subtract A from B to get the time interval between the two 
GPSDO, since both timestamp measurements are against a common timescale.  The 
TICC has a mode to output the (B-A) difference, so it can act as either a 
traditional time interval counter, or as a two-channel timestamping counter.

And as noted in my other message to Luciano, the TICC can also output both 
timestamp and time interval data simultaneously to allow three-corner-hat 
measurements of (A-C, B-C, B-A) where C is the 10 MHz reference.

John


On 11/27/2016 09:24 AM, Bob Camp wrote:

Hi

Without doing a bunch of actual *work* I’m not sure what is inside the 
guts of the board. Being
lazy I’ll just guess ….

There appears to be a 10 MHz time base input and a pair of measurement inputs. 
In a lot us will
be comparing to a “house standard�. That standard has a pps output 
that is related directly to
the 10 MHz reference. If I can uniquely identify one edge (out of 10 million 
edges) as the right
edge, I can use the 10 MHz as my pps reference. Put another way, I don’t 
really need to measure
a pps input from the house standard if I’m already locked up in phase to 
the 10 MHz. All I need to
do is to tag an edge / reset a counter.

The advantage of this is that I may not need another fancy TDC chip to set up 
the reference. I can
use *both* inputs for DUT’s rather than using one as a reference.

Part of the reason I’m guessing this would work is the claim that boards 
can be stacked for multiple
input setups ….

Bob


On Nov 27, 2016, at 7:36 AM, timeok <tim...@timeok.it> wrote:


   Hi John,
I have planned to buy two TICC.
An interesting feature would be to be able to do two simultaneous acquisitions,
and Timelab as real time display,using the two indipendent input channels and 
the 10Mhz clock as single reference.
Luciano
www.timeok.it


   From "time-nuts" time-nuts-boun...@febo.com
   To "Discussion of precise time and frequency measurement" time-nuts@febo.com
   Cc
   Date Wed, 23 Nov 2016 10:48:57 -0500
   Subject [time-nuts] New Timestamping / Time Interval Counter: the TICC
   Counters with resolution below 1 nanosecond are difficult. They require
   either outrageous clock speeds, or interpolators that are typically a
   bunch of analog components mixed with black magic and stirred by
   frequent calibration. The very best single-shot resolution that's been
   commercially available is 22 picoseconds in the HP 5370A/B, with jitter
   somewhat more than that. My 5370B has an one-second noise ADEV of about
   4x10e-11.

   With the help of some very talented friends, I've been working on a ne

Re: [time-nuts] New Timestamping / Time Interval Counter: the TICC

[John Ackermann N8UR]

Good guess.  The 10 MHz reference drives all the logic on the board, and 
particularly the counter that maintains a local timescale in 100us 
increments; the TDC7200 interpolates between the 100us ticks to stamp 
incoming events on channel A and/or B with picosecond precision.  The 
stamps on both channels are referenced to the same local timescale.


Therefore, you can do a measurement of a PPS source against the 10 MHz 
reference and the resulting timestamp output can be processed by TimeLab 
or whatever into stability data (the requirement being that the software 
knows how to deal with timestamps that increment by the nominal 
measurement rate, e.g., 1 second per measurement for PPS data).


So with PPS from GPSDO "A" on channel A the timestamp output after 
unwrapping will show the phase of A vs. 10 MHz.


You can add PPS from GPSDO "B" on channel B and the TICC will also 
output timestamps of B vs. the 10 MHz source.


If you want, you can subtract A from B to get the time interval between 
the two GPSDO, since both timestamp measurements are against a common 
timescale.  The TICC has a mode to output the (B-A) difference, so it 
can act as either a traditional time interval counter, or as a 
two-channel timestamping counter.


And as noted in my other message to Luciano, the TICC can also output 
both timestamp and time interval data simultaneously to allow 
three-corner-hat measurements of (A-C, B-C, B-A) where C is the 10 MHz 
reference.


John


On 11/27/2016 09:24 AM, Bob Camp wrote:

Hi

Without doing a bunch of actual *work* I’m not sure what is inside the guts 
of the board. Being
lazy I’ll just guess ….

There appears to be a 10 MHz time base input and a pair of measurement inputs. 
In a lot us will
be comparing to a “house standard�. That standard has a pps output that is 
related directly to
the 10 MHz reference. If I can uniquely identify one edge (out of 10 million 
edges) as the right
edge, I can use the 10 MHz as my pps reference. Put another way, I don’t 
really need to measure
a pps input from the house standard if I’m already locked up in phase to the 
10 MHz. All I need to
do is to tag an edge / reset a counter.

The advantage of this is that I may not need another fancy TDC chip to set up 
the reference. I can
use *both* inputs for DUT’s rather than using one as a reference.

Part of the reason I’m guessing this would work is the claim that boards can 
be stacked for multiple
input setups ….

Bob


On Nov 27, 2016, at 7:36 AM, timeok  wrote:


   Hi John,
I have planned to buy two TICC.
An interesting feature would be to be able to do two simultaneous acquisitions,
and Timelab as real time display,using the two indipendent input channels and 
the 10Mhz clock as single reference.
Luciano
www.timeok.it


   From "time-nuts" time-nuts-boun...@febo.com
   To "Discussion of precise time and frequency measurement" time-nuts@febo.com
   Cc
   Date Wed, 23 Nov 2016 10:48:57 -0500
   Subject [time-nuts] New Timestamping / Time Interval Counter: the TICC
   Counters with resolution below 1 nanosecond are difficult. They require
   either outrageous clock speeds, or interpolators that are typically a
   bunch of analog components mixed with black magic and stirred by
   frequent calibration. The very best single-shot resolution that's been
   commercially available is 22 picoseconds in the HP 5370A/B, with jitter
   somewhat more than that. My 5370B has an one-second noise ADEV of about
   4x10e-11.

   With the help of some very talented friends, I've been working on a new
   counter called the "TICC" with <60ps resolution and similar jitter,
   based the Texas Instruments TDC7200 time-to-data-converter chip. The
   noise ADEV is about 7x10e-11, not much worse than the 5370,
   but here's the trick: the TICC is an Arduino shield (mounting a Mega
   2560 controller) that weighs a couple of ounces, requires *no*
   calibration, and is powered from a USB cable!

   The TICC is implemented as a two-channel timestamping counter. That
   means it can measure or two low-frequency (e.g., pulse-per-second)
   inputs against an external 10 MHz reference, or it can do a traditional
   time interval measurement of input against the other. It can also
   measure period, ratio, or any other function of two-channel timestamp
   data. (And by the way -- multiple TICCs can be connected to yield 4, 6,
   8, or more synchronized channels, though we haven't tested this
   capability yet.)

   I've attached a picture of the TICC prototype as well as an ADEV plot of
   a 17+ day run of multiple measurements taken by two TICCs, and also
   showing the TICC noise floor. The good news behind that plot is that
   there are more than 6 million data points behind these results, and
   there was not a single glitch or significant outlier among them.

   There's more information available at http://febo.com/pages/TICC

   The software is open source (BSD license) and is 

Re: [time-nuts] New Timestamping / Time Interval Counter: the TICC

[John Ackermann N8UR]

Hi Luciano --

Glad to hear that!

The capability you asked for already exists (great minds think alike...)

In timestamp mode, the TICC will output the stamps for each channel 
independently, measured against the common 10 MHz reference.  So if both 
channels are active, you'll see a bunch of lines something like:


1.234567891234 chA
1.234567892345 chB
2.234567890434 chA
2.234567892789 chB

Recent beta versions of TimeLab can acquire multiple channels on a 
single serial port; there are a couple of magic setup commands in the 
"Acquire" dialog that will allow TimeLab to receive the above and 
display it as two separate traces.


There is also a three-cornered-hat capability, though it's a bit of a 
hack.  The TICC has a "TimeLab" mode which will output two timestamps as 
above, but in addition "chC" which is the time interval (B-A).


Since TimeLab requires all the input signals to be in the same format, 
the chC output is munged into a fake timestamp like this (adding the 
integer part of chB to the B-A difference):


1.234567891234 chA
1.234567892345 chB
1. chC
2.234567890434 chA
2.234567892789 chB
2.2355 chC

With both TICC and TimeLab configured this way, you can do 
three-cornered-hat measurements in real time, which is pretty cool.


When I get a chance, I'll document the setup for this in the TICC 
operation manual.


John

On 11/27/2016 07:36 AM, timeok wrote:


Hi John,
I have planned to buy two TICC.
An interesting feature would be to be able to do two simultaneous acquisitions,
and Timelab as real time display,using the two indipendent input channels and 
the 10Mhz clock as single reference.
Luciano
www.timeok.it


From "time-nuts" time-nuts-boun...@febo.com
To "Discussion of precise time and frequency measurement" time-nuts@febo.com
Cc
Date Wed, 23 Nov 2016 10:48:57 -0500
Subject [time-nuts] New Timestamping / Time Interval Counter: the TICC
Counters with resolution below 1 nanosecond are difficult. They require
either outrageous clock speeds, or interpolators that are typically a
bunch of analog components mixed with black magic and stirred by
frequent calibration. The very best single-shot resolution that's been
commercially available is 22 picoseconds in the HP 5370A/B, with jitter
somewhat more than that. My 5370B has an one-second noise ADEV of about
4x10e-11.

With the help of some very talented friends, I've been working on a new
counter called the "TICC" with <60ps resolution and similar jitter,
based the Texas Instruments TDC7200 time-to-data-converter chip. The
noise ADEV is about 7x10e-11, not much worse than the 5370,
but here's the trick: the TICC is an Arduino shield (mounting a Mega
2560 controller) that weighs a couple of ounces, requires *no*
calibration, and is powered from a USB cable!

The TICC is implemented as a two-channel timestamping counter. That
means it can measure or two low-frequency (e.g., pulse-per-second)
inputs against an external 10 MHz reference, or it can do a traditional
time interval measurement of input against the other. It can also
measure period, ratio, or any other function of two-channel timestamp
data. (And by the way -- multiple TICCs can be connected to yield 4, 6,
8, or more synchronized channels, though we haven't tested this
capability yet.)

I've attached a picture of the TICC prototype as well as an ADEV plot of
a 17+ day run of multiple measurements taken by two TICCs, and also
showing the TICC noise floor. The good news behind that plot is that
there are more than 6 million data points behind these results, and
there was not a single glitch or significant outlier among them.

There's more information available at http://febo.com/pages/TICC

The software is open source (BSD license) and is available at
https://github.com/TAPR/TICC -- the current version seems be reliable
but there are still features to add and a *lot* of cleanup to do; it's
currently ugly and very much a work in process.

As always, I'll be making the TICC available through TAPR. We're still
finalizing details, but we expect the price to be less than $200 for a
turn-key system: TICC mounted an Arduino with software loaded and
tested for basic functionality. We hope to ship the TICC by February.

I'll post a note in a week or two with final price and ordering
information. As a heads up, we will probably offer a small discount for
pre-orders. TAPR is a shoestring non-profit group and the up-front cost
to manufacture this unit will frankly be a challenge for us. Getting
pre-orders will help our cash flow significantly, so we ask you to keep
that in mind.

John
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Re: [time-nuts] New Timestamping / Time Interval Counter: the TICC

[John Ackermann N8UR]

Hi Dave --

I should clarify -- this UI is just a character-based menu system using 
a dumb terminal program.  The code is implemented within the Arduino.


It's written in the somewhat nonstandard C/C++ used by the Arduino IDE. 
 This morning I'm going to add a "TODO-UI" file to the git repository 
explaining what the menu system needs to do.


TimeLab is able to read the data stream and plot results in real-time, 
so there's no urgent need for software on the host end.  But I do need 
to allow the user to set a number of configuration parameters without 
having to recompile the code, so that's the urgent goal.


Thanks!
John

On 11/25/2016 03:26 AM, David wrote:

John,

   In what language is the GUI written?  I might be able to help on
that, or other parts of the software, if someone else hasn't yet
volunteered.

Dave, WA8YWQ

On 2016-11-24 06:43, John Ackermann N8UR wrote:


Hi Anders --

Thanks, and thanks for the info on the 53230A.  I have not used one of
those myself but the data sheet lists 20ps single-shot.

Also I should note that the TICC does not compete with counters like
the 53230A for high speed measurement, or frequency counting.  It does
far fewer measurements per second than the high-end counters -- my
design criteria was for use in PPS measuring system.

With the current software, the actual measurement processing time is
about 1 millisecond; we may be able to optimize a hundred or two
microseconds from that as the code currently has more 64 bit
operations than are necessary, and there are other things that can
surely be tweaked.

The killer is the serial output via USB.  It can take up to 10 ms to
output 20 characters, and that's what really limits the measurement
rate.  I'm pretty sure this can be improved (one idea is to buffer
results to reduce USB packetization delays), but there's other
functionality that I need to finish first.

BTW -- the software is open source and on github at
https://github.com/TAPR/TICC , so I welcome anyone who wants to work
on it.  Bug fixes are gladly accepted, and if you're looking for work
to do, I could use a volunteer to work on a couple of areas, most
critically finishing a UI that will allow the user to set operating
parameters.

John

On 11/24/2016 02:40 AM, Anders Wallin wrote:

Nice work!
On the website in the introduction you mention 22ps single-shot
time-stamping on the 5370A/B.
I think it's well established that the 53230A does about 11-12 ps for
time-intervals, which corresponds to about 9 ps single-channel. see for
example:
http://www.anderswallin.net/wp-content/uploads/2015/04/53230A_PPS_skew.png

Anders


On Wed, Nov 23, 2016 at 11:13 PM, Peter Vince <petervince1...@gmail.com
<mailto:petervince1...@gmail.com>>
wrote:


Fantastic John - well done!  Yes, I'll definitely put an order in as soon
as possible.

  Regards,

  Peter  (G8ZZR, London)
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Re: [time-nuts] New Timestamping / Time Interval Counter: the TICC

[John Ackermann N8UR]

Thanks, Bruce, I'll update the web page to reference the 53230A as the 
best resolution device currently available.


On 11/24/2016 01:03 PM, Bruce Griffiths wrote:

John

There is an application note or similar on the 53230A that indicates that
the single shot noise for time interval measurement is typically about 13ps
or so.

Bruce
On Thursday, November 24, 2016 09:43:54 AM John Ackermann N8UR
wrote:

Hi Anders --

Thanks, and thanks for the info on the 53230A.  I have not used one of
those myself but the data sheet lists 20ps single-shot.

Also I should note that the TICC does not compete with counters like the
53230A for high speed measurement, or frequency counting.  It does far
fewer measurements per second than the high-end counters -- my

design

criteria was for use in PPS measuring system.

With the current software, the actual measurement processing time is
about 1 millisecond; we may be able to optimize a hundred or two
microseconds from that as the code currently has more 64 bit

operations

than are necessary, and there are other things that can surely be

tweaked.


The killer is the serial output via USB.  It can take up to 10 ms to
output 20 characters, and that's what really limits the measurement
rate.  I'm pretty sure this can be improved (one idea is to buffer
results to reduce USB packetization delays), but there's other
functionality that I need to finish first.

BTW -- the software is open source and on github at
https://github.com/TAPR/TICC , so I welcome anyone who wants to work

on

it.  Bug fixes are gladly accepted, and if you're looking for work to
do, I could use a volunteer to work on a couple of areas, most
critically finishing a UI that will allow the user to set operating
parameters.

John


On 11/24/2016 02:40 AM, Anders Wallin wrote:

Nice work!
On the website in the introduction you mention 22ps single-shot
time-stamping on the 5370A/B.
I think it's well established that the 53230A does about 11-12 ps for
time-intervals, which corresponds to about 9 ps single-channel. see

for

example:
http://www.anderswallin.net/wp-content/uploads/2015/04/53230A_PPS_skew.png

Anders


On Wed, Nov 23, 2016 at 11:13 PM, Peter Vince

<petervince1...@gmail.com>


wrote:

Fantastic John - well done!  Yes, I'll definitely put an order in as soon
as possible.

   Regards,

   Peter  (G8ZZR, London)

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Re: [time-nuts] New Timestamping / Time Interval Counter: the TICC

[John Ackermann N8UR]

Thanks, Andrew.  Yes, it is weird how the Arduino folks choose what 
capabilities to expose on the board.  From some testing I did, it seems 
that the Arduino handles the 100 kHz interrupt rate without too much 
strain -- it became a bigger issue at 250 kHz or above -- but the timers 
would have been a more elegant approach if they had been available.


John


On 11/24/2016 02:49 AM, Andrew Rodland wrote:

On Wed, Nov 23, 2016 at 10:48 AM, John Ackermann N8UR <j...@febo.com> wrote:

The TICC is implemented as a two-channel timestamping counter.  That means
it can measure one or two low-frequency (e.g., pulse-per-second) inputs
against an external 10 MHz reference, or it can do a traditional time
interval measurement of one input against the other.  It can also measure
period, ratio, or any other function of two-channel  timestamp data.  (And
by the way -- multiple TICCs can be connected to yield 4, 6, 8, or more
synchronized channels, though we haven't tested this capability yet.)


Very exciting, I will definitely be wanting one :)

There's *almost* a way to do the coarse timer counting with almost no
CPU overhead, but unfortunately the Arduino folks were terribly
inconsistent about which timer signals they decided to assign to
Arduino pins. Of the six external clocks for timers, they brought out
two (T0 and T5), and of the four input captures, they brought out two
(ICP4 and ICP5). If they had brought out T4 then with a little bit of
timer configuration you could use COARSE to clock TIMER4 and TIMER5 in
lockstep, run STOP_A and STOP_B to ICP4 and ICP5, and instead of
interrupting at 10kHz to increment PICcount, you would only have to
interrupt every 6.5536 seconds to increment the upper bits. Plus
handling the actual events of course. I find that very appealing, but
unfortunately, T4 is out of reach of a shield.

Andrew
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Re: [time-nuts] New Timestamping / Time Interval Counter: the TICC

[John Ackermann N8UR]

Hi Anders --

Thanks, and thanks for the info on the 53230A.  I have not used one of 
those myself but the data sheet lists 20ps single-shot.


Also I should note that the TICC does not compete with counters like the 
53230A for high speed measurement, or frequency counting.  It does far 
fewer measurements per second than the high-end counters -- my design 
criteria was for use in PPS measuring system.


With the current software, the actual measurement processing time is 
about 1 millisecond; we may be able to optimize a hundred or two 
microseconds from that as the code currently has more 64 bit operations 
than are necessary, and there are other things that can surely be tweaked.


The killer is the serial output via USB.  It can take up to 10 ms to 
output 20 characters, and that's what really limits the measurement 
rate.  I'm pretty sure this can be improved (one idea is to buffer 
results to reduce USB packetization delays), but there's other 
functionality that I need to finish first.


BTW -- the software is open source and on github at 
https://github.com/TAPR/TICC , so I welcome anyone who wants to work on 
it.  Bug fixes are gladly accepted, and if you're looking for work to 
do, I could use a volunteer to work on a couple of areas, most 
critically finishing a UI that will allow the user to set operating 
parameters.


John

On 11/24/2016 02:40 AM, Anders Wallin wrote:

Nice work!
On the website in the introduction you mention 22ps single-shot
time-stamping on the 5370A/B.
I think it's well established that the 53230A does about 11-12 ps for
time-intervals, which corresponds to about 9 ps single-channel. see for
example:
http://www.anderswallin.net/wp-content/uploads/2015/04/53230A_PPS_skew.png

Anders


On Wed, Nov 23, 2016 at 11:13 PM, Peter Vince 
wrote:


Fantastic John - well done!  Yes, I'll definitely put an order in as soon
as possible.

  Regards,

  Peter  (G8ZZR, London)
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Re: [time-nuts] How phase stable is rg59 or alternate coax

[John Ackermann N8UR]

Several years ago I measured the delay of about 80 feet of LMR400 
feeding a GPS antenna, much of which was lying on a black shingle roof 
in the Georgia sun.  I checked in early afternoon when the sun was 
beating, and in the wee hours of the morning, to get the greatest 
temperature delta.  My recollection is that the tempco was surprisingly 
small -- maybe a couple of nanoseconds.  It was much less than the other 
elements of the GPS timing error budget.


I can't find the data right now, but will keep digging.  There's also a 
short paper from the early 2000s from Haystack on their measurement of 
LMR400 in an environmental chamber.  They came to the same conclusion, 
but I can't find that paper either. :-(


I don't know how much different RG58 results would be.

John


On 11/21/2016 09:38 AM, Scott Stobbe wrote:

If you had 30 ft of rg59 outdoors seeing maybe 10 degC swings everyday,
would the propagation time be stable to ps? ns?

On Sun, Nov 20, 2016 at 7:04 PM Hal Murray  wrote:



Is that even a sensible question?  Is there a better way to phrase it?


The problem I'm trying to avoid is that the weather and the satellite
geometry change over time so I can't just collect data for X hours, switch
to
the other antenna or move the antenna to another location, collect more
data,
then compare the two chunks of data.

The best I can think of would be to setup a reference system so I can
collect
data from  2 antennas and 2 receivers at the same time.  It would probably
require some preliminary work to calibrate the receivers.  I think I can do
that by swapping the antenna cables.


If I gave you a pile of data, how would you compute a quality number?  Can
I
just sum up the S/N slots for each visible/working satellite?


--
These are my opinions.  I hate spam.



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Re: [time-nuts] 53132 replacement fan

[John Ackermann N8UR]

Thanks, all for the tips.  Glad to know it's a standard size so there's 
plenty of choice.


John


On 11/21/2016 12:57 PM, jimlux wrote:

On 11/21/16 6:39 AM, Charles Steinmetz wrote:

Tom wrote:


EFB0412MD
Airflow 7.17 CFM
6300 RPM
Noise 24 dBA

FBK04F12U
Same exact form factor.
Air Flow 9.2 CFM
9500 RPM
Noise 42 dB(A)


Note the 18dB greater noise (that's a HUGE difference).  Even with bad
bearings in the original fan, it is probably considerably quieter (by
10dB or more) than the proposed replacement.  On the other hand, the
replacement moves 28% more air, which may be a good thing.



That's a 40mm fan, which is a standard size, I'll bet you can find a
slower turning/quieter fan.

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[time-nuts] 53132 replacement fan

[John Ackermann N8UR]

Does anyone have a part number for the 53132 fan (or equivalent)?  Mine 
is getting pretty noisy.


Thanks!
John
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Re: [time-nuts] I love the smell of tantalum in the morning

[John Ackermann N8UR]

Either hot tweezers or a hot air rework station are the best/easiest 
ways to remove dead parts.  But two fine-tip soldering irons will also 
work and are a lot cheaper.  The idea is to heat both ends of the part 
at once, and when the solder flows, lift or flip the part off.  Then, 
use some liquid flux and narrow solder wick to suck off the excess 
solder, and you should end up with nice smooth pads ready for the 
replacement part.


The key thing to avoid damage is to make sure the solder is really 
flowing on both pads before you try to lift the part.  Sometimes ground 
pads have enough thermal mass that it takes a while to get them hot 
enough.  Be patient.


Good luck!
John


On 11/05/2016 03:12 PM, Tom Van Baak wrote:

See C13 in the attached photo. I need to replace some blown caps on a few 
boards [1]. In one instance the cap got so hot it melted itself off the board. 
Quiet convenient, actually -- it acts like its own fuse -- but I don't think 
the 5071 designers had that clever feature in mind.

Having not done SMT before, how should I do it with minimal risk to the very 
precious PCB. Or, what equipment should I use this as a good excuse to buy?

Thanks,
/tvb

[0] http://www.imdb.com/title/tt0078788/quotes
[1] http://leapsecond.com/museum/hp5071a/A1-mother.htm



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[time-nuts] TNS-BUF Update

[John Ackermann N8UR]

We had enough interest in the TNS-BUF isolation amplifier project to go 
ahead with a production run.  Thanks!


The order has been placed with our contract manufacturer in Hungary and 
we expect the boards to arrive at the TAPR office in Texas around 
January 1, plus or minus shipping and customs delays.  It'll take a 
little while for the office to recover from New Year's Eve, so we expect 
to get all orders shipped by mid-January.


If you placed an order, you'll be getting an email from TAPR with 
further details. And of course if the schedule changes, I'll provide an 
update.


BTW -- depending on manufacturing yield, there may be a few extra 
assembled boards available, as well as some bare PCB.  I'll announce 
when we know for sure.


Thanks, all.

John
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Re: [time-nuts] Temp/Humidity control systems?

[John Ackermann N8UR]

On 10/27/2016 11:06 AM, Poul-Henning Kamp wrote:


This is why a lot of people in costal climates who ventilate their
basement during summer "to dry out the basement" get the exact
opposite result:  The air outside is a lot wetter than on the inside.


I learned this myself last summer.  We have a cottage on northern Lake 
Michigan that is about 100 feet from the water.  There is a walk-out 
basement that gets somewhat damp, though a dehumidifier usually keeps it 
under control.  Last summer I opened the cottage later in the season 
than usual, and the basement was very clammy.  So I decided to open the 
slider doors and turn on a box fan to air things out...


When I came back downstairs a couple of hours later, *standing water* 
had condensed on the cold floor tiles!  I had basically been 
dehumidifying Lake Michigan.  Lesson learned (and I spent the rest of 
the vacation trying to dry things out again).


Thanks for all the other comments in this thread.  I'm absorbing and 
will try to summarize back to the group.


John
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Re: [time-nuts] Temp/Humidity control systems?

[John Ackermann N8UR]

On 10/26/2016 1:00 PM, Richard (Rick) Karlquist wrote:

On 10/26/2016 8:59 AM, John Ackermann N8UR wrote:

I may have the opportunity to build a small "clock room" and am
considering whether I could make it an environmentally controlled space.
 I'd like to learn about the options for doing this.

The space would probably be 6x8 feet or so, in a basement with one
outside wall.


I'm lost with the basic concept here.  Help me understand this.


This room would be a large closet in my basement where two racks of 
various OCXO, Rb, Cs live. There wouldn't be a lot of in-and-out 
traffic. I'm not looking for 0.01 degree regulation -- <1 degree C and a 
few percent humidity throughout the year seems a reasonable goal.


What I envisioned was a very small heat pump or other heating/air-con 
unit coupled with some sort of proportional control. I just don't know 
where to start looking for that, or what other issues to be thinking about.


(I know the way time-nuts think, and I recall the great ideas posted 
here in the past about using an old refrigerator, or burying standards 
in a deep hole -- but this would be wrapped into a bigger construction 
project that I'm going to be managing from a distance, so I need to keep 
it fairly straight-forward.)


Thanks, all!

John

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Re: [time-nuts] Temp/Humidity control systems?

[John Ackermann N8UR]

Hi Bill --

That's a bit more than I had in mind, but very cool. :-)  What I really 
meant was a heat pump or other unit with good control loop that I could 
use in a standard insulated space, just to keep "nominal" conditions 
(ie, not wide-range testing).


Thanks,
John


On 10/26/2016 12:09 PM, William H. Fite wrote:

John, this is what I bought for the Orlando VA Medical Center when I was
setting up the research lab there.

Not cheap, though.  螺

https://www.thermalproductsolutions.com/products/walk-in-temperature-humidity-test-rooms

On Wed, Oct 26, 2016 at 11:59 AM, John Ackermann N8UR <j...@febo.com> wrote:


I may have the opportunity to build a small "clock room" and am
considering whether I could make it an environmentally controlled space.
I'd like to learn about the options for doing this.

The space would probably be 6x8 feet or so, in a basement with one outside
wall.

Can anyone point me to purveyors of the hardware to do something like
this?  Because I'll have a limited time to build this, I'm looking for
something that uses more-or-less off the shelf gear, and not a whole lot of
custom engineering.

Thanks!
John
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[time-nuts] Temp/Humidity control systems?

[John Ackermann N8UR]

I may have the opportunity to build a small "clock room" and am 
considering whether I could make it an environmentally controlled space. 
 I'd like to learn about the options for doing this.


The space would probably be 6x8 feet or so, in a basement with one 
outside wall.


Can anyone point me to purveyors of the hardware to do something like 
this?  Because I'll have a limited time to build this, I'm looking for 
something that uses more-or-less off the shelf gear, and not a whole lot 
of custom engineering.


Thanks!
John
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[time-nuts] Fwd: TNS-BUF High Isolation, Low Noise Buffer Amp Available

[John Ackermann N8UR]

We've received enough orders to go ahead with production on the TNS-BUF, 
so here's your last chance to join the cool kids -- we'll take orders at 
http://tapr.org/kits_tns-buf through tomorrow, Oct. 20.


John
 Forwarded Message 
Subject: [time-nuts] TNS-BUF High Isolation, Low Noise Buffer Amp Available
Date: Wed, 5 Oct 2016 10:15:46 -0400

I've previously mentioned a high performance buffer amplifier called the
"TNS-BUF" that I built based on a design by Dr. Bruce Griffiths with
further input from John Miles. Key numbers are:

*  Phase noise -140dBc/Hz at 1 Hertz offset, noise floor -175dBc/Hz.
(PN plot attached)
*  Reverse isolation greater than 100dB; low enough that I can't make a
trustworthy measurement.
*  Gain from -10 to +7 dB from 1 to 30 MHz; maximum output >18dBm.
*  Nominal 18VDC operation, but works down to 12V with lowered
maximum output level.

There's information, including performance data and schematic, at
http://www.febo.com/pages/TNS-BUF

There seems to be some interest in an amplifier like this, so TAPR has
decided to do a limited production run.  The amp is built with surface
mount parts, so we thought an assembled and tested board was better than
a kit.  The price will be $119 each.  But we have no idea how much
interest there is, and we need to build a minimum of 25 units to make
production feasible.

So, here's the deal:  you can order your TNS-BUF at

http://tapr.org/kits_tns-buf

through *October 20*.  If we receive orders for at least 25 boards by
then, we will charge credit cards and place the production order with
our contract manufacturer.  If we don't get 25 orders, we'll cancel the
project and credit cards will not be charged.  There's no guarantee that
boards will be available for later order.

We expect about 60 days between placing the manufacturing order and
receipt of the boards at TAPR.  We'll ship to customers ASAP after
receipt.  So that means you can expect to receive your order shortly
after January 1.

So, go to http://tapr.org/kits_tns-buf now to place your order before
the deadline!

John




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Re: [time-nuts] TNS-BUF High Isolation, Low Noise Buffer Amp Available

[John Ackermann N8UR]

Hi Chris --

The input and output are straight SMAs mounted on the back of the PCB. 
The idea is that you can mount it in the cover of a small die-cast box 
secured by the SMA hardware (I used a Hammond BB1590N1).  All you have 
to do is drill a couple of 3/16 holes, plus another hole for a power 
feedthrough.


This is a buffer amp, not a distribution amp, so it's a single channel 
circuit, and high isolation was one of the key design criteria.


John


On 10/12/2016 09:08 AM, Chris Caudle wrote:

On Wed, October 5, 2016 9:15 am, John Ackermann N8UR wrote:

I've previously mentioned a high performance buffer amplifier called the
"TNS-BUF" that I built based on a design by Dr. Bruce Griffiths with
further input from John Miles.


None of the pictures have shown the connector side of the assembled PCB.
Does the layout accommodate mounting in an enclosure?

And is this layout just a single channel of the buffer design?  In other
words only for buffering an oscillator to a single other device for
preventing crosstalk or injection locking, not for distribution.


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[time-nuts] Fwd: TNS-BUF High Isolation, Low Noise Buffer Amp Available

[John Ackermann N8UR]

Just a reminder that the deadline to order TNS-BUF isolation amps is 
next week -- October 20.


John

 Forwarded Message 
Subject: [time-nuts] TNS-BUF High Isolation, Low Noise Buffer Amp Available
Date: Wed, 5 Oct 2016 10:15:46 -0400
From: John Ackermann N8UR <j...@febo.com>
Reply-To: Discussion of precise time and frequency measurement 
<time-nuts@febo.com>
To: Discussion of precise time and frequency measurement 
<time-nuts@febo.com>


I've previously mentioned a high performance buffer amplifier called the
"TNS-BUF" that I built based on a design by Dr. Bruce Griffiths with
further input from John Miles. Key numbers are:

*  Phase noise -140dBc/Hz at 1 Hertz offset, noise floor -175dBc/Hz.
(PN plot attached)
*  Reverse isolation greater than 100dB; low enough that I can't make a
trustworthy measurement.
*  Gain from -10 to +7 dB from 1 to 30 MHz; maximum output >18dBm.
*  Nominal 18VDC operation, but works down to 12V with lowered
maximum output level.

There's information, including performance data and schematic, at
http://www.febo.com/pages/TNS-BUF

There seems to be some interest in an amplifier like this, so TAPR has
decided to do a limited production run.  The amp is built with surface
mount parts, so we thought an assembled and tested board was better than
a kit.  The price will be $119 each.  But we have no idea how much
interest there is, and we need to build a minimum of 25 units to make
production feasible.

So, here's the deal:  you can order your TNS-BUF at

http://tapr.org/kits_tns-buf

through *October 20*.  If we receive orders for at least 25 boards by
then, we will charge credit cards and place the production order with
our contract manufacturer.  If we don't get 25 orders, we'll cancel the
project and credit cards will not be charged.  There's no guarantee that
boards will be available for later order.

We expect about 60 days between placing the manufacturing order and
receipt of the boards at TAPR.  We'll ship to customers ASAP after
receipt.  So that means you can expect to receive your order shortly
after January 1.

So, go to http://tapr.org/kits_tns-buf now to place your order before
the deadline!

John




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Re: [time-nuts] TNS-BUF High Isolation, Low Noise Buffer Amp Available

[John Ackermann N8UR]

It's possible we may have some bare boards, but no guarantees at this point.

On 10/5/2016 2:04 PM, Dan Rae wrote:

For those of us who aren't scared of surface mount stuff, and maybe even
prefer it, will there be any bare boards available?

Dan - ac6ao
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[time-nuts] TNS-BUF High Isolation, Low Noise Buffer Amp Available

[John Ackermann N8UR]

I've previously mentioned a high performance buffer amplifier called the 
"TNS-BUF" that I built based on a design by Dr. Bruce Griffiths with 
further input from John Miles. Key numbers are:


*  Phase noise -140dBc/Hz at 1 Hertz offset, noise floor -175dBc/Hz.
   (PN plot attached)
*  Reverse isolation greater than 100dB; low enough that I can't make a
   trustworthy measurement.
*  Gain from -10 to +7 dB from 1 to 30 MHz; maximum output >18dBm.
*  Nominal 18VDC operation, but works down to 12V with lowered
   maximum output level.

There's information, including performance data and schematic, at
http://www.febo.com/pages/TNS-BUF

There seems to be some interest in an amplifier like this, so TAPR has 
decided to do a limited production run.  The amp is built with surface 
mount parts, so we thought an assembled and tested board was better than 
a kit.  The price will be $119 each.  But we have no idea how much 
interest there is, and we need to build a minimum of 25 units to make 
production feasible.


So, here's the deal:  you can order your TNS-BUF at

http://tapr.org/kits_tns-buf

through *October 20*.  If we receive orders for at least 25 boards by 
then, we will charge credit cards and place the production order with 
our contract manufacturer.  If we don't get 25 orders, we'll cancel the 
project and credit cards will not be charged.  There's no guarantee that 
boards will be available for later order.


We expect about 60 days between placing the manufacturing order and 
receipt of the boards at TAPR.  We'll ship to customers ASAP after 
receipt.  So that means you can expect to receive your order shortly 
after January 1.


So, go to http://tapr.org/kits_tns-buf now to place your order before 
the deadline!


John

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Re: [time-nuts] COTS cesium standard physics package life

[John Ackermann N8UR]

I think there are two separate issues to consider:

1.  Cesium depletion, which only occurs when the tube is operating with 
cesium oven on, and high voltage at the other end; and


2.  Tube vacuum and other physical aspects that may deteriorate over 
time, whether or not the tube is operating.  The routine ion pumping 
helps keep the vacuum up in storage, but is not as effective as the 
continuous pumping that occurs during operation.


This is guesswork, but I suspect the warranty period was based on (1), 
which is why it is shorter on the high-performance tubes, which deplete 
cesium more rapidly.  There may also have been an assumption that not 
many customers were buying Cs standards and putting them in storage.


John

On 9/29/2016 1:16 PM, Ruslan Nabioullin wrote:

On 09/29/2016 01:03 PM, Bob Camp wrote:

2) How long on average is the tube likely to be useful.


So you are implying that the package life is depleted at a roughly equal
rate regardless of whether the package is fully operating, has just the
pump operating, or is completely shut off?

-Ruslan
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Re: [time-nuts] 53132A triggering

[John Ackermann N8UR]

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

> On Sep 16, 2016, at 1:21 PM, Bob Camp <kb...@n1k.org> wrote:
> 
> Hi
> 
> Set it to:
> 
> 1) DC coupled (AC does not go low enough)
> 2) 50 ohms if your driving source will tolerate it, otherwise 1 meg ohm.
> 3) Manual trigger mode (Auto is to fast and it forgets where the trigger 
> should be)
> 4) Trigger level around 1/2 the PPS P-P voltage
> 
> Once set up that way, the triggering should be pretty solid. There is still 
> the wonderful stuff about pulses that 
> arrive on top of each other ….
> 
> Bob
> 
>> On Sep 16, 2016, at 1:10 PM, John Ackermann N8UR <j...@febo.com> wrote:
>> 
>> I'm fairly new to driving the 53132 and it seems to be quite a pain to set 
>> up reliable triggering for TTL-level pulses (e.g., PPS).  Simply leaving it 
>> to auto-trigger sure doesn't do the trick.  Any suggestions on optimum 
>> trigger settings for this use?
>> 
>> Thanks!
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[time-nuts] 53132A triggering

[John Ackermann N8UR]

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

Thanks!
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Re: [time-nuts] GPS message jitter (was GPS for Nixie Clock)

[John Ackermann N8UR]

Long ago I measured the impact of the linux low_latency flag on a 16550 UART.  
I don't know where that data is sitting now, but I remember that it made a 
significant difference.

> On Jul 18, 2016, at 9:59 PM, Hal Murray  wrote:
> 
> 
> jim...@earthlink.net said:
>> except that virtually every UART in use today has some sort of buffering
>> (whether a FIFO or double buffering) between the CPU interface and the  bits
>> on the wire, which completely desynchronizes the bits on the wire  from the
>> CPU interface.
> 
> The idea was to reduce the CPU load processing interrupts by batching things 
> up.
> 
> Some of those chips generate an interrupt when the see a return or line-feed 
> character.
> 
> Most of them have an option to disable that batching.  On Linux the setserial 
> command has a low_latency option.  I haven't measured the difference.  It 
> would be a fun experiment.
> 
> 
> -- 
> These are my opinions.  I hate spam.
> 
> 
> 
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Re: [time-nuts] Visiting Greenwich

[John Ackermann N8UR]

I'm a bit of a crypto-geek and was able to visit Bletchley a couple of 
times, again many years ago.  It is definitely worth a trip, though from 
what I saw on my visits and have read lately it has evolved badly.


It used to be run on a shoestring with enthusiastic volunteers 
everywhere and lots of eccentric touches.  There were local craft clubs 
who set up on their niche historical displays on the weekends, there was 
a guy who'd taken over the front room of the manor with his huge 
Churchill memorabilia collection, and though things weren't fancy they 
were lots of fun.  Over the years, though, the site has been 
"corporatized" and while the exhibits have gotten fancier, some of the 
fun has gone away, and a lot of the passionate volunteers seem to have 
given up.


My last visit was years ago, though, and I hope that what I've read 
about what's happened since is overstated.


John

On 7/4/2016 10:01 PM, Bob wrote:

Hi Dave,

Yes, as many mentioned all the clocks are up the hill at the Observatory, and 
very much worth the trip.  As you mention you are with your family, I would 
like to add that yes I did cajole my family to the NMM and the Observatory, but 
also to Bletchley Park (just a short train ride outside London) and Bletchley 
Park was easily the most memorable.  There are wonderful volunteer guides, and 
many interesting devices that you can get up close to.  Bletchley was more like 
visiting a working lab than a museum.  I think every time nut would enjoy 
Bletchley quite a bit.

https://www.bletchleypark.org.uk/ 

Cheers,

Bob


On Jul 4, 2016, at 6:31 PM, Dave Martindale  wrote:

I am in London England at the moment, playing tourist with the rest of my
family.  I want one day to be a visit to the National Maritime Museum at
Greenwich, which includes the Royal Observatory Greenwich.  I am
particularly interested in seeing Harrison's H1 through H4, plus other
high-precision mechanical timekeepers (pendulum clocks, etc).

I know they are at the NMM - their web site shows some of them.  But where
are they located on the site?  The NMM has a large main building down near
the Thames, while the Royal Observatory and related buildings are on the
top of a hill further inland in Greenwich Park.  Are the chronometers and
other precision timekeepers on display somewhere in the Royal Observatory,
or down in the main NMM building?  I've spent an hour or two browsing web
sites without finding this particular bit of information.

I figure there must be list members who have visited the NMM, and know
where the precision timekeepers are actually displayed.

Thanks,
Dave
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Re: [time-nuts] Visiting Greenwich

[John Ackermann N8UR]

When I was there (10+ years ago) the timekeeping stuff was at the observatory, 
which is just a few minutes walk up from the NMM.  Both sites are fascinating 
and well worth spending some time.

I took a tour boat to get to Greenwich from central London -- it's the end of 
the line and if you work the times right you can get on another one for the 
return trip.  The boat ride was also well worth it.

Have fun!
John

> On Jul 4, 2016, at 6:31 PM, Dave Martindale  wrote:
> 
> I am in London England at the moment, playing tourist with the rest of my
> family.  I want one day to be a visit to the National Maritime Museum at
> Greenwich, which includes the Royal Observatory Greenwich.  I am
> particularly interested in seeing Harrison's H1 through H4, plus other
> high-precision mechanical timekeepers (pendulum clocks, etc).
> 
> I know they are at the NMM - their web site shows some of them.  But where
> are they located on the site?  The NMM has a large main building down near
> the Thames, while the Royal Observatory and related buildings are on the
> top of a hill further inland in Greenwich Park.  Are the chronometers and
> other precision timekeepers on display somewhere in the Royal Observatory,
> or down in the main NMM building?  I've spent an hour or two browsing web
> sites without finding this particular bit of information.
> 
> I figure there must be list members who have visited the NMM, and know
> where the precision timekeepers are actually displayed.
> 
> Thanks,
> Dave
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Re: [time-nuts] OT stuffing boards: was GPS interface/prototyping

[John Ackermann N8UR]

You know, this thread has had a tremendous amount of practical information, 
with actual URLs, etc.  Would someone be willing to consolidate the info on a 
web page somewhere?

> On Jun 24, 2016, at 9:56 AM, Oz-in-DFW  wrote:
> 
> On 6/23/2016 10:53 PM, Chris Albertson wrote:
>>> Am I missing some obvious cheapie oven without these types of problems?
>> 
>> A lot of people are building them from Black and Decker (and the like)
>> toaster ovens.  Use Arduino for controller or just eyeballs. oven
>> thermometer and wrist watch.It is not rocket science the Arduino
>> controller software reads a thermocouple and controls an on/off relay.
>> Lots of instructions around if you google for reflow toaster oven.
> I'm using a
> PicoReflow.https://apollo.open-resource.org/mission:resources:picoreflow 
> It's Raspberry Pi based, so the board cost is about the same as an
> Arduino, but I use my tablet as the user interface AND tweaking profile
> is trivial unlike most of the Arduino based stuff. The system uses an
> internal web server and can be connected to a local monitor, or a web
> interface. All the control logic is in Python. I used the tablet browser
> and I don't need to stand next to it to monitor operation. This is
> particularly handy when I'm baking out parts.  I hand wired the
> interface board (trivial I/O) and used a purchase MAX31855 based board
> for another $20 from
> http://www.playingwithfusion.com/productview.php?pdid=19=1001
> (love the site name)
> 
> -- 
> mailto:o...@ozindfw.net
> Oz
> POB 93167 
> Southlake, TX 76092 (Near DFW Airport) 
> 
> 
> 
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Re: [time-nuts] Measuring receiver...

[John Ackermann N8UR]

I've seen references that at least by the latter part of WW2 oscillographs were 
being used to identify transmitters and/or ops.  It should be possible to 
deduce chirp, rise time, fall time of signals, all of which characterize the 
transmitter, as well as element spacing and other characteristics that help 
identify the operator, from oscilloscope snapshots of the demodulated audio at 
various sweep speeds.


> On Jun 21, 2016, at 7:02 PM, Alan Melia  wrote:
> 
> TX "fingerprinting" in WWII
> You seem to be forgetting that there were very few of the sophisticated 
> digital timing systems were available 75 years ago. Traffic analysis was 
> started early in 1938 or even before. By 1939 we knew all the nets used in 
> Europe and had "Y" ( a corruption of WI, Wireless Intercept )operators 
> monitoring the nets. Many of these were amateurs and they were allocated to 
> specific nets and followed them around as they moved. They became very 
> familiar with the "accents" of operators on their nets, and particularly 
> before 1939 security procedures were very lax and "chatting" 
> common-place.but it was all aural.
> 
> I suspect serious transmitter parameter logging was not done before the cold 
> war when spectrum analysers, or at least pan-adapters became more readily 
> available. To keep a little OnTopic .you would have difficulty doing this 
> with a BC-221.!! :-)) A crystal clock of this period was at least one fully 
> utilised 6foot 19inch rack (there is one at Grenwich.)
> Alan
> G3NYK
> 
> 
> Alan
> G3NYK
> 
> - Original Message - From: "jimlux" 
> To: 
> Sent: Tuesday, June 21, 2016 10:02 PM
> Subject: Re: [time-nuts] Measuring receiver...
> 
> 
>>> On 6/21/16 11:28 AM, Brooke Clarke wrote:
>>> Hi:
>>> 
>>> During W.W.II there were secret methods of "fingerprinting" radio
>>> transmitters and separately the operators.
>>> I suspect the transmitter fingerprinting involved things like frequency
>>> accuracy, stability, CW rise and decay time,  For the operator some
>>> from of statistics on the timings associated with sending Morse Code.
>>> But. . .  I haven't seen any papers describing this.  Can anyone point
>>> me to a paper on this?
>> For "human controlled" stuff, e.g. recognizing someone's "fist", there's a 
>> huge literature out there on biometric identification looking at things like 
>> keyboard and mouse click timing - the timing requirements are pretty slack, 
>> and hardly time-nuts level, unless you're looking to do it with mechanical 
>> devices constructed from spare twigs and strands of kelp.
>> 
>> There have been a variety of schemes for recognizing individual radios by 
>> looking at the frequency vs time as they start up. Likewise, it's pretty 
>> easy to distinguish radar magnetrons from each other.  Not a lot of papers 
>> about this, but you'll see it in advertising literature, or occasionally in 
>> conference pubs (although I can't think of any off hand).  There was someone 
>> selling a repeater access control system that was based on the transmitter 
>> fingerprint.
>> 
>> But the real reason why you don't see any publications is that this stuff is 
>> pretty classic signals intelligence (SIGINT or MASINT) and it is still being 
>> used, and is all classified. You're not relying on Betty the receiver 
>> operator to recognize the characteristic chirp as the agent's radio is 
>> keyed, it's all done by computer now, but the basic idea is the same.  And 
>> as with most of this stuff, the basics are well known, but the practical 
>> details are not, or, at least, are the proprietary secret sauce in any 
>> practical system. (In a significant understatement, Dixon, in "Spread 
>> Spectrum Systems" makes some comment about how synch acquisition is the 
>> difficult part and won't be described in the book)
>> 
>> You might look at the unclassified proceedings of conferences like MILCOM 
>> and find something.  Googling with MASINT might also help.
>> 
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Re: [time-nuts] Goodie for British Timenuts!!!

[John Ackermann N8UR]

Boy, that looks an awful lot like a re-branded Sulzer 5 with Sulzer power 
supply!

> On Jun 7, 2016, at 1:38 PM,   wrote:
> 
> Hi,
> 
> Saw this while trolling for goodies!
> 
> http://www.mullardmagic.co.uk/racal-ma259-frequency-standard-ra17-ra117-r
> af-navy-goldfinger-james-bond-ra1218-ra1772-ra1792-ma50-ra181
> 
> RACAL MA259 FREQUENCY STANDARD FROM 1965 
> 
> Looks neat
> 
> Cheers,
> 
> Corby
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