Re: [time-nuts] Newbie to Time Nuts; Seeking wisdom, re Hydrogen MASER applications

[Jeremy Nichols]

The TV series "How the States Got Their Shapes" mentions boundary errors
occasionally. There were some magnificent errors that took years to
resolve. In most cases today, the boundary is what it is and the fact that
it's a few inches or feet in error is usually ignored. Many boundaries are
a function of watercourses that change over time; the Mississippi is famous
for doing that such that there's actually a part of Illinois (I think) on
the west side of the Mississippi because the river changed its course.

Jeremy


On Mon, Nov 13, 2017 at 5:10 AM Mike Cook  wrote:

>
> > Le 13 nov. 2017 à 12:12, Hal Murray  a écrit :
> >
> >
> > michael.c...@sfr.fr said:
>  prior to my senior project most geodetic surveyors  used a Wooden
> boxed,
>  marine chronometer, to get sub second UT1 time, or  back then, GMT
> >
> >>> How did you get the data out of the wooden box?
> >
> >>  I have a couple of marine chronometers that have electrical contacts
> >> closing once a second. This signal is relayed by wires to terminals on
> the
> >> outside of the box.
> >
> > That gets you seconds if you count them.  How do you get sub seconds?
> Just
> > count time since the PPS using a normal crystal and it will be good
> enough?
>
>  In a sense.. When I was in the merchant navy in the 60s there were no
> crystal watches, so when taking sights we « transferred time » to a good
> 1/5sec stepping deck watch previously synchronized to the chronometer which
> of course was kept in the shelter of the Bridge. As this was done just
> prior to sights the offset would be known to less than or equal to that
> increment.  Marine chronometers may not be particularly accurate, but they
> can be extremely stable at about +/- 0.2sec or better per day variation.
> The daily drift being known from the clocks last rating, getting accurate
> offset timing from GMT was possible. The clocks themselves were re-rated
> every year. I’m in France and I don’t think that any borders in Europe were
> defined by astronomical observation, but in the US I believe that at least
> some of the state borders were thus fixed. As a second’s error in time will
> be about a nautical mile in US latitudes, I wonder if anyone has measured
> with GPS, how good the original
>   surveys were.?
>
>
> >
> >
> > --
> > These are my opinions.  I hate spam.
> >
> >
> >
> > ___
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> "The power of accurate observation is commonly called cynicism by those
> who have not got it. »
> George Bernard Shaw
>
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Re: [time-nuts] Newbie to Time Nuts; Seeking wisdom, re Hydrogen MASER applications

[Mike Cook]

> Le 13 nov. 2017 à 12:12, Hal Murray  a écrit :
> 
> 
> michael.c...@sfr.fr said:
 prior to my senior project most geodetic surveyors  used a Wooden boxed,
 marine chronometer, to get sub second UT1 time, or  back then, GMT
> 
>>> How did you get the data out of the wooden box?
> 
>>  I have a couple of marine chronometers that have electrical contacts
>> closing once a second. This signal is relayed by wires to terminals on the
>> outside of the box. 
> 
> That gets you seconds if you count them.  How do you get sub seconds?  Just 
> count time since the PPS using a normal crystal and it will be good enough?

 In a sense.. When I was in the merchant navy in the 60s there were no crystal 
watches, so when taking sights we « transferred time » to a good 1/5sec 
stepping deck watch previously synchronized to the chronometer which of course 
was kept in the shelter of the Bridge. As this was done just prior to sights 
the offset would be known to less than or equal to that increment.  Marine 
chronometers may not be particularly accurate, but they can be extremely stable 
at about +/- 0.2sec or better per day variation. The daily drift being known 
from the clocks last rating, getting accurate offset timing from GMT was 
possible. The clocks themselves were re-rated every year. I’m in France and I 
don’t think that any borders in Europe were defined by astronomical 
observation, but in the US I believe that at least some of the state borders 
were thus fixed. As a second’s error in time will be about a nautical mile in 
US latitudes, I wonder if anyone has measured with GPS, how good the original
  surveys were.?


> 
> 
> -- 
> These are my opinions.  I hate spam.
> 
> 
> 
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"The power of accurate observation is commonly called cynicism by those who 
have not got it. »
George Bernard Shaw

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Re: [time-nuts] Newbie to Time Nuts; Seeking wisdom, re Hydrogen MASER applications

[Hal Murray]

michael.c...@sfr.fr said:
>>> prior to my senior project most geodetic surveyors  used a Wooden boxed,
>>> marine chronometer, to get sub second UT1 time, or  back then, GMT

>> How did you get the data out of the wooden box?

>   I have a couple of marine chronometers that have electrical contacts
> closing once a second. This signal is relayed by wires to terminals on the
> outside of the box. 

That gets you seconds if you count them.  How do you get sub seconds?  Just 
count time since the PPS using a normal crystal and it will be good enough?


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Re: [time-nuts] Newbie to Time Nuts; Seeking wisdom, re Hydrogen MASER applications

[Mike Cook]

> Le 13 nov. 2017 à 01:29, Hal Murray  a écrit :
> 
> 
> apollo...@gmail.com said:
>> prior to my senior project most geodetic surveyors  used a Wooden boxed,
>> marine chronometer, to get sub second UT1 time, or  back then, GMT
> 
> How did you get the data out of the wooden box?
> 
  I have a couple of marine chronometers that have electrical contacts closing 
once a second. This signal is relayed by wires to terminals on the outside of 
the box.
  One came from a Tashkent astronomical observatory and is Sidereal time rated, 
the other is a nautical instrument which would probably have been connected to 
slave clocks.   
  

"The power of accurate observation is commonly called cynicism by those who 
have not got it. »
George Bernard Shaw

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Re: [time-nuts] Newbie to Time Nuts; Seeking wisdom, re Hydrogen MASER applications

[Hal Murray]

apollo...@gmail.com said:
> prior to my senior project most geodetic surveyors  used a Wooden boxed,
> marine chronometer, to get sub second UT1 time, or  back then, GMT

How did you get the data out of the wooden box?


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Re: [time-nuts] Newbie With a Z3801 Problem

[Mike Seguin]

Hi Dave,

For power supply voltages, did you check here:

http://www.realhamradio.com/GPS_Frequency_Standard.htm

Scroll down the page a bit to get to the power supply info.

Your problem is very odd. I retired my Z3801A a while back as it was 
seeing an occasional error. I should drag it back out and see what it does.


Mike

On 11/4/2016 8:23 PM, Dave Hallidy wrote:

Hal-
I took your suggestion and sure enough, I can see on the scope that it puts
out a string on power up.  I'm sure that's why SatStat gives me a
"Communications established- please wait" then "Checking echo".  But then it
all seems to fall apart, because after that, it drops back to "Trying to
establish communications" and "No response..." until I power down then back
up, and it repeats the cycle.

I don't have any real info on power supply voltages, so I don't know what
they should be.  On power up, it goes through the cycle of briefly lighting
the LEDs on the main board red, ending with the green blinking one on the
main board at the same time cycling through the front panel LEDs and ending
with just the power LED lit.  I can pull it apart and check for caps needing
replacement if you think that might be a cause of this.

Dave

-Original Message-
From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Hal Murray
Sent: Friday, November 04, 2016 6:56 PM
To: Discussion of precise time and frequency measurement
Cc: hmur...@megapathdsl.net
Subject: Re: [time-nuts] Newbie With a Z3801 Problem

I would put a scope on the TX line from the Z3801A and power cycle it.  I'm
pretty sure it prints out the version string on power up.

Have you checked the power supplies?  Or looked for old electrolytics?




--

73,
Mike, N1JEZ
"A closed mouth gathers no feet"
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Re: [time-nuts] Newbie With a Z3801 Problem

[Gerhard Hoffmann]

Am 05.11.2016 um 12:51 schrieb Bill Riches:

Hi Mark,

Thank you for working with the KS24361.  Looking forward to when the program 
will be available.

Any ideas on being able to use the 1 PPS signal out of the KS24361 to drive SL 
sound card calibration?  It is a weird pulse and someone mentioned the timing 
is wrong.  I use the pulse out of a Jackson unit with SL and it works fine.



In  ,

I have described a 1pps-Buffer, frequency doubler 5->10MHz and 
distribution amplifier
for the KS24361.  You may not want to build it, but there are pictures 
of the

1pps timing of the Lucent and and also a pic that shows where you can get
the internal 1pps in LVCMOS / TTL level. Buffer it to your taste and 
feed it

to a new BNC / SMA / whatever on the front plate.

73, Gerhard, DK4XP

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Re: [time-nuts] Newbie With a Z3801 Problem

[Bill Riches]

Hi Mark,

Thank you for working with the KS24361.  Looking forward to when the program 
will be available.  

Any ideas on being able to use the 1 PPS signal out of the KS24361 to drive SL 
sound card calibration?  It is a weird pulse and someone mentioned the timing 
is wrong.  I use the pulse out of a Jackson unit with SL and it works fine.

73, 

Bill, WA2DVU

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Re: [time-nuts] Newbie With a Z3801 Problem

[paul swed]

I guess what I heard so far sounds normal on start.
Just the green power led.
Then it warms up and takes a long time up to 48 hours to acquire the
satellites if it has no battery backup and has been off a long time.
Not sure when the messages go active.
Regards
Paul
WB8TSL

On Fri, Nov 4, 2016 at 9:02 PM, n2lym <n2...@optonline.net> wrote:

> Have you tried a loop back connection, short pins 2 and 3 and a terminal
> program? You may have to disable hardware handshaking in hardware manager
> for that USB device or possibly a baud rate problem.
>
>
> Mike
>
>
>
>
>
> On Fri, Nov 04, 2016 at 08:23 PM, Dave Hallidy wrote:
>
> Hal-
>> I took your suggestion and sure enough, I can see on the scope that it
>> puts
>> out a string on power up.  I'm sure that's why SatStat gives me a
>> "Communications established- please wait" then "Checking echo".  But then
>> it
>> all seems to fall apart, because after that, it drops back to "Trying to
>> establish communications" and "No response..." until I power down then
>> back
>> up, and it repeats the cycle.
>>
>> I don't have any real info on power supply voltages, so I don't know what
>> they should be.  On power up, it goes through the cycle of briefly
>> lighting
>> the LEDs on the main board red, ending with the green blinking one on the
>> main board at the same time cycling through the front panel LEDs and
>> ending
>> with just the power LED lit.  I can pull it apart and check for caps
>> needing
>> replacement if you think that might be a cause of this.
>>
>> Dave
>>
>> -Original Message-
>> From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Hal
>> Murray
>> Sent: Friday, November 04, 2016 6:56 PM
>> To: Discussion of precise time and frequency measurement
>> Cc: hmur...@megapathdsl.net
>> Subject: Re: [time-nuts] Newbie With a Z3801 Problem
>>
>> I would put a scope on the TX line from the Z3801A and power cycle it.
>> I'm pretty sure it prints out the version string on power up.
>>
>> Have you checked the power supplies?  Or looked for old electrolytics?
>>
>>
>> --
>> These are my opinions.  I hate spam.
>>
>>
>>
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Re: [time-nuts] Newbie With a Z3801 Problem

[n2lym]

Have you tried a loop back connection, short pins 2 and 3 and a terminal 
program? You may have to disable hardware handshaking in hardware 
manager for that USB device or possibly a baud rate problem.



Mike




On Fri, Nov 04, 2016 at 08:23 PM, Dave Hallidy wrote:


Hal-
I took your suggestion and sure enough, I can see on the scope that it 
puts

out a string on power up.  I'm sure that's why SatStat gives me a
"Communications established- please wait" then "Checking echo".  But 
then it
all seems to fall apart, because after that, it drops back to "Trying 
to
establish communications" and "No response..." until I power down then 
back

up, and it repeats the cycle.

I don't have any real info on power supply voltages, so I don't know 
what
they should be.  On power up, it goes through the cycle of briefly 
lighting
the LEDs on the main board red, ending with the green blinking one on 
the
main board at the same time cycling through the front panel LEDs and 
ending
with just the power LED lit.  I can pull it apart and check for caps 
needing

replacement if you think that might be a cause of this.

Dave

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

Sent: Friday, November 04, 2016 6:56 PM
To: Discussion of precise time and frequency measurement
Cc: hmur...@megapathdsl.net
Subject: Re: [time-nuts] Newbie With a Z3801 Problem

I would put a scope on the TX line from the Z3801A and power cycle it. 
I'm pretty sure it prints out the version string on power up.


Have you checked the power supplies?  Or looked for old electrolytics?


--
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Re: [time-nuts] Newbie With a Z3801 Problem

[Dave Hallidy]

Hal-
I took your suggestion and sure enough, I can see on the scope that it puts
out a string on power up.  I'm sure that's why SatStat gives me a
"Communications established- please wait" then "Checking echo".  But then it
all seems to fall apart, because after that, it drops back to "Trying to
establish communications" and "No response..." until I power down then back
up, and it repeats the cycle.

I don't have any real info on power supply voltages, so I don't know what
they should be.  On power up, it goes through the cycle of briefly lighting
the LEDs on the main board red, ending with the green blinking one on the
main board at the same time cycling through the front panel LEDs and ending
with just the power LED lit.  I can pull it apart and check for caps needing
replacement if you think that might be a cause of this.

Dave

-Original Message-
From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Hal Murray
Sent: Friday, November 04, 2016 6:56 PM
To: Discussion of precise time and frequency measurement
Cc: hmur...@megapathdsl.net
Subject: Re: [time-nuts] Newbie With a Z3801 Problem

I would put a scope on the TX line from the Z3801A and power cycle it.  I'm 
pretty sure it prints out the version string on power up.

Have you checked the power supplies?  Or looked for old electrolytics?


-- 
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Re: [time-nuts] Newbie With a Z3801 Problem

[Hal Murray]

I would put a scope on the TX line from the Z3801A and power cycle it.  I'm 
pretty sure it prints out the version string on power up.

Have you checked the power supplies?  Or looked for old electrolytics?


-- 
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Re: [time-nuts] Newbie With a Z3801 Problem

[Dave Hallidy]

I should add to this- On power up of the receiver, the SatStat window does
say "Communications established- please wait." Then "Checking echo" Then it
goes into the repetitive "Trying to establish communications" and "No
response." every 3.5 seconds or so.

 

Dave

  _  

From: Dave Hallidy [mailto:k2...@frontier.com] 
Sent: Friday, November 04, 2016 5:48 PM
To: 'time-nuts@febo.com'
Subject: Newbie With a Z3801 Problem

 

Hi all-

Dave K2DH here.  I'm new to the group as of today.  I have an old HP Z3801A
that I've had for years and which has been packed away for several years.
It worked when I put it away, but now, although it seems to come up
correctly, I have no serial comms with it.

I'm looking for a little help here, maybe a new suggestion or two.  I'll
tell you what I've tried.

 

When I used it before, I used it with an old Fujitsu laptop running (I
think) Windows 98SE.  I had modified the Z3801's port for RS-232 and it
worked fine for several years.

 

When I got it out the other day, I used the same cable that I had made for
it before (basically a null modem, crossing RXD and TXD).  I loaded SatStat
and tried to run it, but it wouldn't communicate with the receiver.  The
current computer is a Win 7 laptop with a Prolific USB to Serial converter,
but I also tried several XP computers, with the same result.

 

I've confirmed that I'm using the correct com port and I've gotten to the
point of even putting a scope on the RS-232 output and input on the
receiver.  I see requests to connect coming into the Z3801, but no response
of any kind- the 232 line just stays low.  I backed up to the serial driver
chip on the 3801's main board (an LT1180 RS-232 driver/receiver) and the
receiver is passing the request on to the processor, but the driver is not
changing state.  So apparently, the processor on the board doesn't recognize
the command SatStat is sending to it.

 

I've tried the recommended baud rate of 19200,7, O,1 but also just about all
other combinations- thinking maybe the old Fujitsu wasn't capable of 19200
and I might have changed the baud rate.  But all to no avail, and frankly, I
wonder if the 19200,7O,1 configuration isn't hard-coded into the Z3801 and
can't be changed.

 

I've made sure my com port setting on the computers' device managers
correspond to the settings I'm using in SatStat, so the setting should allow
the two to talk to each other.

 

I've had it on for numerous long periods and it hasn't achieved GPS lock,
but I assume that's because it's not in survey mode and I was in a different
location last time I used it.  It goes into holdover after a period of time.

 

Has anyone else experienced this and if so, were you able to overcome it
successfully?  RS-422 isn't really an option and as I said, it used to work
fine via RS-232.

 

Thanks in advance for any assistance- I've become quite interested in
precision time and would like to get this thing running again.

 

73

Dave K2DH

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Re: [time-nuts] Newbie questions

[Bob Camp]

Hi

> On Jan 27, 2016, at 7:56 PM, time...@metachaos.net wrote:
> 
> Bob, et. al.,
> 
> Thanks for the advice and information. That has helped a lot in closing some
> holes and gives me a lot to consider. I am continuing to research and learn,
> this is not a short term project as in building it this week or month. I need
> to learn and work up to the full project. I will probably start small with
> pieces and gather what equipment I can. Like many of my projects, this one
> will probably have multiple sub-projects. Especially if I manage to snag test
> equipment that needs repair.
> 
> Regrettably, the 260 was ordered from China, there were none from the US when
> I ordered. I did know that it would be a crap shoot, but for $26 it was
> something I could get now. I might even be lucky!
> 
> I am planning on including sawtooth correction in hardware. But, I have a good
> bit to learn for that. It appears to be fairly simple given your processor
> reads the sawtooth correction from the GPS receiver and sets up a programmable
> delay for each cycle.

It’s far more common to sum the correction into your control loop. 

Bob

> 
> I have a dozen pieces floating in my head, I am certain I will be back for
> more advice.
> 
> Thanks again.
> 
> 
> Mike
> 
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Re: [time-nuts] Newbie questions

[Bob Camp]

Hi

> On Jan 27, 2016, at 11:08 AM, Jim Harman  wrote:
> 
> I am a relative newbie here myself, but at the risk of starting a
> firestorm, I would take issue with some of what Bob says below. See
> comments interspersed.
> 
> 
> On Wed, Jan 27, 2016 at 7:43 AM, Bob Camp  wrote:
> 
>> Hi
>> 
>> Ok, so let me answer the questions you *should* have asked:
>> 
>> (They are in no particular order. Number 3 probably should come first)
>> 
>> 1) Is the gear I have enough to do this project?
>> 
>> No, you will need some sort of frequency  / time standard. An atomic
>> clock of some sort is pretty much a minimum. You probably also need
>> a working GPSDO (or set of them) for comparison as well. You will also
>> need a working / modern precision counter that will give you data down
>> in the < 100 ps range.
>> 
> 
> This depends on your answer to #3 below. For my GPSDO, project, all I have
> is a scope, DMM, and PC. I can't measure ADEV, but by setting the time
> constant of my filter to 1000 sec and monitoring the TIC output I can be
> pretty certain that my local reference is well within 100 nsec of the
> "true" time.

Except you have no idea if you have messed up the performance at < 1000 
seconds. Unfortunately 
there are a *lot* of ways to do that .


> 
>> 
>> 2) How will this ultimately be built?
>> 
>> At the very least, you will be building this with surface mount devices.
>> If it’s a scratch build, you will be dealing with fine pitch parts. That
>> gets
>> you into a whole bunch of gear. It also gets you into a very real “is this
>> fun or not” sort of question.
>> 
> 
> For my GPSDO I started with and Arduino board and a solderless breadboard.
> Anything with an SMD is on a purchased breakout board that spreads its pins
> to 0.1" centers. You do have to be careful to keep the wires short when
> working with fast rise times. I migrated this to a solder-type breadboard
> that mimics the layout of the solderless board and it is working fine.

Which is yet another branch to the decision tree. There are literally thousands
of possible branches. We could spend a lot of time enumerating all of them. 


> 
>> 
>> 3) What *is* the goal?
>> 
>> "I’m going to make dinner” is the start of a process. It’s not enough of a
>> goal to accomplish the task. Starting the task with a general objective is
>> fine.
>> It does need to be refined a bit before you go much further.
>> 
> 
> Agreed.
> 
>> 
>> Is this what most of us would call a GPSDO (self contained box) or is it
>> something with a PC in the middle of it?
>> 
> 
> Mine runs either stand-alone or with a PC to monitor it.
> 
>> 
>> Is this an OCXO based “precision” device or is it something more simple?
>> 
> 
> I used a $25.00 surplus OCXO. Eventually I may invest in something better
> but then I would have to get a timing GPS to go with it. Currently I am
> using the $40.00 Adafruit module.

Hopefully you got lucky with your OCXO. Others have had to buy a few dozen
before they got a “good” one. 

> 
>> 
>> Is a pure software solution good enough?
>> 
> 
> Mine is almost all software, but it has a TIC that consists of a 74HC4046
> phase detector chip, a diode, a cap, and 2 resistors, feeding an A/D input
> of the Arduino processor board. This gives a resolution of 1 ns.

….. but can you relate resolution to stability / accuracy / noise and all the 
other things that
need to be checked. Resolution is normally the easy part….This example gets 
directly back to
the test gear question. 

> 
>> 
>> Each of those decisions (and that’s by no means a full list) will send you
>> off
>> in a very different direction.
>> 
> For sure!
> 
>> 
>> 4) How long is this likely to take?
>> 
>> Best guess based on the others who have done the same thing - several
>> years.
>> 
> 
> I have been at it on and off for about two years but I have learned a lot
> along the way.
> 
>> 
>> 5) How much is this likely to cost?
>> 
>> If done the way others have done it, several thousand dollars up to
>> quite a bit more than that.
>> 
> 
> My total investment (not including the scope, DMM, and laptop PC) is under
> $200.

….. but you really do not know what it’s doing  in all respects. My example 
was targeted at a more fully worked out solution. Again it’s a matter of “what
is your target"


> 
>> 
>> 6) How much research is involved?
>> 
>> Quite a bit. The information you need is scattered all over the place.
>> Figure
>> that you likely will read at least several hundred papers. There is a whole
>> statistical language that is unique to these gizmos. This is *not* a
>> follow a
>> set recipe sort of project.
>> 
> 
> Again, depends on your answer to #3. I started with a working design and
> code and modified it to suit my fancy. I am pleased with the result. It
> keeps the brain cells firing.
> 
>> 
>> Lots of fun !!!
>> 
> 
> Absolutely!!


Bob

> 
> 
> -- 
> 
> --Jim Harman
> ___
> time-nuts mailing list -- 

Re: [time-nuts] Newbie questions

[Bob Camp]

Hi

(a few minor additions ..)

> On Jan 27, 2016, at 4:04 PM, Attila Kinali  wrote:
> 
> Moin,
> 
> As no-one seems to want to answer the GPS related questions
> 
> 
> On Tue, 26 Jan 2016 19:04:10 -0500
> time...@metachaos.net wrote:
> 
>> 
>> Paradoxically, I have no interest in time. As in time of day, day of week,
>> etc.. I have never had a job where I got to work on time. My philosophy has
>> always been "go to bed when sleepy, get up when not". I was notorious in high
>> school for only showing up on test day. But, I am interested in being able to
>> timestamp events accurately and in measuring time (and other things). I am
>> also interested in how a very accurate frequency source can be used in
>> other applications and test instruments. That brings me to my desire to build
>> a GPSDO and my questions.
> 
> I have wirtten a couple of mails with references to popular GPSDO's
> a couple of times in the past. You might want to have a look at them
> and the discussions they were in:
> 
> https://www.febo.com/pipermail/time-nuts/2012-March/064873.html
> https://www.febo.com/pipermail/time-nuts/2013-June/077368.html
> 
> 
>> I have also been researching GPS antennas. From what I can see there are two
>> basic types - the flat puck and the helical. 
> 
> There are actually many more, but the cross dipole, the spiral antenna
> and the two you mentioned are by far the most popular ones.
> 
> 
>> I have not seen anything to
>> distinguish the two types based on performance or usage or to indicate that
>> one or the other might be better for GPS timing.
> 
> What makes good antennas and what not is actually not that easy to define.
> There was a discussion on this last spring. look for
> "Important parameters for a GPS/GNSS antenna" in the archives.
> 
>> However, I have seen "GPS
>> Timing Reference Antennas" advertised. Most or all of those appear to be
>> helical. But, I have not seen anything that specifies the difference between 
>> an active GPS antenna and an active GPS Timing Reference Antenna.
> 
>>   1. What is the difference between a "normal" GPS antenna and a GPS Timing
>>  Reference antenna? What features are of interest?
> 
> The timing reference antennas are usually build by manufacturers with the
> intended use for high precision instruments. Either timing or geodetic survey.
> Their parameters are more strictly controlled, they have (usually) a more
> stable phase center and some of them are also dual band (L1/L2).
> 
> Unless you need sub-ns stability and accuracy or have a dual band receiver,
> go for a standard antenna.

One more parameter - they are designed to be outdoors pretty much forever and 
ever. 
The “rain sealing” details are much better addressed than a normal mag mount 
antenna. 

> 
> 
>>   2. Is there anything extra needed besides a GPS antenna to enable the use
>>  of WAAS or other services? Apparently the ubolt receivers can make use
>>  of some of that, but it is not clear what is needed to provide that
>>  information to them, or if they just pick it up automatically using a
>>  standard GPS antenna.
> 
> I am not sure what the LEA modules need to active WAAS/EGNOS/etc, it's
> probably listed under one of the commands in the protocol reference.
> 
> You don't need any special antenna for those, as these augmentation
> services use the same frequency as L1 GPS.
> 
>> Also, from what I have read, using carrier phase for timing is potentially
>> more accurate by a couple orders of magnitude. Are there any GPS timing
>> receivers available that use carrier phase? 
> 
> Yes, but they are darn expensive.
> 
>> Or use both L1 and L2 for increased accuracy? 
> 
> Yes, but again, expensive.


As in your “GPS module” goes from $40 to $4,000. Your antenna goes from 
$40 to $1.5K if bought new. 

> 
>> I see that the ubolt receivers can report some carrier
>> phase information, but that doesn't appear to translate to increased 
>> accuracy.
> 
> If anything, it would lead to higher precision ;-)
> 
> The reason why carrier phase tracking does not lead to large improvements
> is because most receivers are single frequency receivers which cannot
> directly calculate the ionospheric corrections. Thus they have to rely
> on predictions send out by the GPS satellites (and by WAAS/EGNOS).
> But even with those predictions, the ionospheric terms will dominate
> the error. Thus there is very little gain from using carrier phase
> tracking over code phase only tracking for an L1 only receiver.

It *can* lead to higher performance, but then you need to correlate against a 
local 
precision site. That turns this into a pretty exotic / single task sort of 
device. 

> 
>> And the LEA M8T use dual channels, but don't appear to mix GPS and GLASNOS to
>> improve accuracy. Do any receivers do that?
> 
> I did not have a look at the M8T yet, so i cannot answer this.
> I am pretty sure that there are dual system timing receivers out there.


Yes you can set 

Re: [time-nuts] Newbie questions

[Artek Manuals]

You will find the following discussion of dB useful

http://www.sengpielaudio.com/calculator-volt.htm

dB references are not just for RF it  is/was used extensively in audio 
work as well where it was often related to 600ohm load vs the 50ohm RF load


As for DMM I have a Tektronix DM501A and a DM502A both have dB scales. I 
have a 20+ year old Radio-Schlock DMM which also has a Db scale. Then 
there are all the analog HP 4xx series all of which have dB scales 
regardless of frequency coverage AC volt meters, RF power meters etc. 
Also the Boonton 92 series all incorporate dBm scales ...and the list 
goes on


Have fun and welcome back to the world of practical electronics 
experimenting.


Dave
NR1DX
ArtekManuals.com

On 1/27/2016 12:41 PM, time...@metachaos.net wrote:

Bill,

Thanks. Your reply was very informative. I understand the reason for using
decibels for the applications you mention. However, I did not consider the
output level of a non-RF signal to be in that category.

You are right, I have never seen a DMM reading in decimals. I know that
digital scopes can do so (and understand how they work), but again I have
never seen or used one. Given the zero point (finally figured that one out, I
was missing the assumed impedance factor which was varying) I can convert
levels - not quite in my head, since I can't do logs in my head - but close
and can get a pretty good guestimate that way.




--
Dave
manu...@artekmanuals.com
www.ArtekManuals.com


---
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Re: [time-nuts] Newbie questions

[Jeremy Nichols]

That hits the nail on the head. Mathematicians (the OP mentioned he was
one) learned long ago that it's easier to add and subtract than to multiply
and divide.

Jeremy


On Wednesday, January 27, 2016, Jim Harman  wrote:

> Another benefit of using dB vs Watts or Volts is that systems often consist
> of a chain of elements with gains and losses. Working with gains and losses
> in dB lets you calculate the signal level at any point along the way and
> the system gain by adding and subtracting rather than multiplying and
> dividing.
>
> On Wed, Jan 27, 2016 at 3:02 AM, wb6bnq >
> wrote:
>
> > Hi Mike,
> >
> > The element that you are missing is the impedance.  When you look at the
> > common formula it refers to a ratio of power or voltage and the impedance
> > is left out with the understanding that the impedance is equal for each
> > power or voltage in the ratio.  The actual formula (for power) is DB =
> 10 X
> > log10 ( E1^2 / R ) / ( E2^2 / R ).  Hint   Power P = E^2 / R.
> >
> > In the RF world that impedance is 50 Ohms and ZERO DBm(illiwatts) is ONE
> > milliwatt into 50 Ohms which is 0.223606797749979 Vrms.
> >
> > In the audio world the reference impedance is 600 Ohms.  So ZERO DBu is
> > One milliwatt into 600 Ohms which is 0.7745966692414834 Vrms.  More
> > commonly referred to as 0.775 Vrms.
> >
> > As for your GPS questions, I will leave that up to others to answer.
> >
> > BillWB6BNQ
> >
> >
> > time...@metachaos.net  wrote:
> >
> > Hi,
> >>
> >> I am a newbie to this list. I have downloaded the archives and read
> about
> >> 5,000 of the past messages. I plan on building my own GPSDO, probably
> >> using a
> >> LEA-6T (but LEA-7T or LEA-M8T would be good if I can find one
> >> affordably). I
> >> have a MTI 260 on order (although it could wind up being a 261 since
> they
> >> all
> >> appear to ship one or the other randomly).
> >>
> >> Currently, my resources include a DMM (well, a couple) and soldering /
> >> desoldering stations and quite a few tools. I also have an oscilloscope
> >> that I
> >> am currently repairing - a 400Mhz Tektronix 2465BCT analog scope. I am
> >> waiting
> >> on the final parts from Mouser. Once that is done I need to get it
> >> calibrated.
> >> All of that will probably take me another month. I also need to finish
> >> fixing
> >> my cassette deck - and then to finish writing a special recording
> program
> >> to
> >> use raw device drivers to get around the fact that Windows is not real
> >> time. I
> >> interrupted that project to work on the scope.
> >>
> >> In the meantime, I am reading the time-nuts messages (and lots of other
> >> things) to gather information and ideas about how I am going to do this
> >> and
> >> generally to learn more.
> >>
> >> So, I have some questions. Let me tell you a bit about me, so that you
> >> know
> >> the context and my limitations. I am a retired programmer. I wrote just
> >> about
> >> everything including device drivers, operating systems, utilities,
> >> various AI
> >> programs, telephone systems, compilers, encryption, web applications and
> >> much
> >> more. If I need to throw 50,000 LOC at a project, no problem. I have
> used
> >> many
> >> languages including quite a few different assembly languages (I have
> also
> >> written an assembler). I consider myself a mathematician / programmer,
> >> although I haven't really needed Calculus or Differential Equations for
> >> decades, so I am pretty rusty in that area. I do more work in formal
> logic
> >> than higher mathematics. But, I THINK like a mathematician. Formalism
> and
> >> abstraction come naturally to me.
> >>
> >> During my career I also helped to debug hardware during S-100 days. I
> have
> >> sporadically messed with electronics off and on, informally, with no
> >> education
> >> in the area. Now that I am retired (and have more time, but less money -
> >> it IS
> >> a zero sum game!), I am trying to learn more about electronics and start
> >> doing
> >> hardware projects. I have never been into model building or anything
> >> similar,
> >> so my construction skills are lacking. I understand a lot of things in
> >> theory,
> >> but practice still eludes me. For example, knowing a part exists or
> >> determining which of 10,000 apparently identical parts is the "right"
> >> choice.
> >> It can hours or even days to find the "right" connector. In many cases,
> >> the
> >> names or descriptions are completely meaningless. That all appears to be
> >> an
> >> experience related issue, so I will (hopefully) overcome that in time.
> >>
> >> I have no problem with soldering / desoldering, but I haven't designed
> or
> >> built my own PCB yet. I have designed / redesigned some minor circuits,
> >> especially on the power supply side. I can follow schematics reasonably
> >> well,
> >> but I am not comfortable with Eagle or other PCB layout programs. Every
> >> time
> >> I have tried one of those 

Re: [time-nuts] Newbie questions

[Jim Harman]

On Tue, Jan 26, 2016 at 7:04 PM,  wrote:

> I am trying to learn more about electronics and start doing
> hardware projects. I have never been into model building or anything
> similar,
> so my construction skills are lacking. I understand a lot of things in
> theory,
> but practice still eludes me.
>

To get a better background in electronics, I would highly recommend "The
Art of Electronics" by Horowitz and Hill. The long awaited and fully
updated 3rd edition came out just last year and it is well worth the $80.00
price. As a person who has worked with electronics on and off since 1960, I
can say it teaches electronics the way I wish I had been taught. It has a
strong emphasis on practical applications and assumes only high school math.

Some here may pooh-poo it, but to get started building useful electronic
systems I would recommend the Arduino platform. Fully assembled processor
boards are about $25.00 from reputable suppliers and have plenty of I/O
pins to get you started. On some versions of the processor you can expand
the I/O by adding "shields" which mate to headers on the processor board.

All you need to do to is to plug the board into a USB port on your PC or
Mac and download the free IDE. Both the hardware and software are open
source so you can see exactly how they work under the covers if you want. A
wide variety of libraries is also available (all free) and there is a
lively user community. The programming language is a stripped-down version
of C++ with a bunch of simple extensions to support analog and digital
I/O.  Once your code is working you can either continue to power the system
through the USB port or run it stand-alone with a 9V battery or wall wart.

I have built a GPSDO based on the design posted here by Lars Walenius a
couple of years ago. It uses the Arduino Micro processor, which is nice
because it has a second serial port. This lets it get serial data from the
GPS and talk to the PC at the same time. I would be happy to post the
schematics and code if you are interested.

-- 

--Jim Harman
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Re: [time-nuts] Newbie questions

[Jim Harman]

I am a relative newbie here myself, but at the risk of starting a
firestorm, I would take issue with some of what Bob says below. See
comments interspersed.


On Wed, Jan 27, 2016 at 7:43 AM, Bob Camp  wrote:

> Hi
>
> Ok, so let me answer the questions you *should* have asked:
>
> (They are in no particular order. Number 3 probably should come first)
>
> 1) Is the gear I have enough to do this project?
>
> No, you will need some sort of frequency  / time standard. An atomic
> clock of some sort is pretty much a minimum. You probably also need
> a working GPSDO (or set of them) for comparison as well. You will also
> need a working / modern precision counter that will give you data down
> in the < 100 ps range.
>

This depends on your answer to #3 below. For my GPSDO, project, all I have
is a scope, DMM, and PC. I can't measure ADEV, but by setting the time
constant of my filter to 1000 sec and monitoring the TIC output I can be
pretty certain that my local reference is well within 100 nsec of the
"true" time.

>
> 2) How will this ultimately be built?
>
> At the very least, you will be building this with surface mount devices.
> If it’s a scratch build, you will be dealing with fine pitch parts. That
> gets
> you into a whole bunch of gear. It also gets you into a very real “is this
> fun or not” sort of question.
>

For my GPSDO I started with and Arduino board and a solderless breadboard.
Anything with an SMD is on a purchased breakout board that spreads its pins
to 0.1" centers. You do have to be careful to keep the wires short when
working with fast rise times. I migrated this to a solder-type breadboard
that mimics the layout of the solderless board and it is working fine.

>
> 3) What *is* the goal?
>
> "I’m going to make dinner” is the start of a process. It’s not enough of a
> goal to accomplish the task. Starting the task with a general objective is
> fine.
> It does need to be refined a bit before you go much further.
>

Agreed.

>
> Is this what most of us would call a GPSDO (self contained box) or is it
> something with a PC in the middle of it?
>

Mine runs either stand-alone or with a PC to monitor it.

>
> Is this an OCXO based “precision” device or is it something more simple?
>

I used a $25.00 surplus OCXO. Eventually I may invest in something better
but then I would have to get a timing GPS to go with it. Currently I am
using the $40.00 Adafruit module.

>
> Is a pure software solution good enough?
>

Mine is almost all software, but it has a TIC that consists of a 74HC4046
phase detector chip, a diode, a cap, and 2 resistors, feeding an A/D input
of the Arduino processor board. This gives a resolution of 1 ns.

>
> Each of those decisions (and that’s by no means a full list) will send you
> off
> in a very different direction.
>
For sure!

>
> 4) How long is this likely to take?
>
> Best guess based on the others who have done the same thing - several
> years.
>

I have been at it on and off for about two years but I have learned a lot
along the way.

>
> 5) How much is this likely to cost?
>
> If done the way others have done it, several thousand dollars up to
> quite a bit more than that.
>

My total investment (not including the scope, DMM, and laptop PC) is under
$200.

>
> 6) How much research is involved?
>
> Quite a bit. The information you need is scattered all over the place.
> Figure
> that you likely will read at least several hundred papers. There is a whole
> statistical language that is unique to these gizmos. This is *not* a
> follow a
> set recipe sort of project.
>

Again, depends on your answer to #3. I started with a working design and
code and modified it to suit my fancy. I am pleased with the result. It
keeps the brain cells firing.

>
> Lots of fun !!!
>

Absolutely!!


-- 

--Jim Harman
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Re: [time-nuts] Newbie questions

[timenut]

Bill,

Thanks. Your reply was very informative. I understand the reason for using
decibels for the applications you mention. However, I did not consider the
output level of a non-RF signal to be in that category.

You are right, I have never seen a DMM reading in decimals. I know that
digital scopes can do so (and understand how they work), but again I have
never seen or used one. Given the zero point (finally figured that one out, I
was missing the assumed impedance factor which was varying) I can convert
levels - not quite in my head, since I can't do logs in my head - but close
and can get a pretty good guestimate that way.


Mike

P.S. I also used punch cards. I kept my source library first on punch cards
and then mag tape. I eventually bought my own IBM disk drive for the 360 at
work. I started on an RCA 70/46 using punch tape in a time sharing
environment. I had a trash-80 before S-100s. I even had a full size IBM tape
drive and four hard disk drives. Never could do anything with them, I just
couldn't get 3-phase 440 in an apartment complex and IBM used some very
unusual logic levels. I eventually gave the hard disk drives away and
abandoned the tape drive. I had the original CP/M source code from Gary
Kildall written in PL/M. Threw all of that stuff out about 10 years ago and
even more a bit more about a year and a half ago. But I still have the MASM
Assembler manuals from Microsoft. Those were last published around 1995 - and
I needed them just a few months ago.


> Hi, MIke. I used the university CDC6400/6600 supercomputer while in
> engineering school with punch cards or Teletypes and was familiar with S-100
> vintage equipment. Somewhere I may still have a MIcrosoft BASIC pre MS-DOS
> (HDOS or CP/M) looseleaf manual. I haven't retired yet, but have been an
> Application Engineer at Tektronix for nearly 30 years. So I can appreciate
> your mindset. I'm going to only answer two of your questions:

> 1. What is the zero value for voltage and watts using logarithmic
>scaling   (at least as used here)? Is there actually a consistent
>underlying value   across all applications?

> 2. Why use it for specifying voltage or power in a limited range? Why
>not   just say that the output is 1.0v rms or 0.7v, or that it uses
>50mW? There   does not appear to be any actual advantage to using a
>logarithmic scale   for a small range of values - and 1mV to 1kV IS a
>small range.   Especially when you have to convert the logarithmic
>value to a "real"   value to actually do anything with it.

> RF and audio (including telephone) types have used logarithmic (dB)
> units for many decades. There is often a need to discuss thermal noise
> levels and transmitter power levels in the same circuit, which can lead
> to very large voltage and power ratios. It's common to need to relate
> voltages over a 10^10 range and powers over a 10^20 range
> (1:0.0001). Engineers and scientists like to use numeric
> values which are easier to work with. You wouldn't want to specify a
> hard drive size as 1,000,000,000,000 bytes but as 1 TB (ignoring the
> power of 2 vs power of 10 issue). So we use "engineering units" (powers
> of 1,000) for frequency (kHz, MHz, GHz, THz), voltage (pV, nV, uV, mV,
> V, kV, MV, GV).

> RF applications are more naturally dealt with in terms of power. The
> noise generated in a resistor due to thermal agitation (Johnson-Nyquist
> noise) is P = kTB, where P = power in watts, k = Boltzmanns constant
> (1.28 x 10^-23 J/K), T = absolute temperature in Kelvins, and B is the
> measurement bandwidth in Hertz. Many RF components are rated by power
> dissipation. Historically it's been much easier to measure RF signals
> levels by measuring thermal changes due to signal power.

> The very large dynamic range required for characterizing sound and
> telephone line levels and relating them to human perceived level change
> led to the definition of the Bel (power ratio of 10, named for Alexander
> Graham Bell). The decibel (1/10 Bel) is the logarithmic unit which is
> used in practice. The noise delivered by a resistor to a matched load at
> room temperature and normalized to a 1 Hz measurement bandwidth is about
> -174 dBm/Hz.

> The "m" in "dBm" stands for 1 mW (milliwatt). So 0 dBm = 1 mW. You
> should read "dBm" as "decibels relative to 1 milliwatt". Since most
> power levels in RF equipment tend to be within a couple of orders of
> magnitude below or above a milliwatt, dBm is the main unit used for RF
> equipment which can fit on your lab bench. In some cases it's convenient
> to use logarithmic voltage units, and the common units are dBuV
> (decibels relative to 1 microvolt), dBmV (decibels relative to 1
> millivolt), or dBV (decibels relative to 1 volt). But except for cable
> television and a few other applications (including noise levels at low
> audio frequencies), dBm rules the RF world.

> You are correct that linear non-logarithmic units work well when a small

Re: [time-nuts] Newbie questions

[timenut]

Jeremy,

While you are right, "real" mathematicians don't have anything to do with
numbers! Its all functions, sets, maps, groups, rings and formal logic (very
tongue in cheek here, of course). All very abstract.

I also understand about the "chain of elements", but my assumption was that it
was a significant part of this arena. Certainly due to my inexperience in the
area.


Mike


> That hits the nail on the head. Mathematicians (the OP mentioned he was
> one) learned long ago that it's easier to add and subtract than to multiply
> and divide.

> Jeremy


> On Wednesday, January 27, 2016, Jim Harman  wrote:

>> Another benefit of using dB vs Watts or Volts is that systems often consist
>> of a chain of elements with gains and losses. Working with gains and losses
>> in dB lets you calculate the signal level at any point along the way and
>> the system gain by adding and subtracting rather than multiplying and
>> dividing.
>>
>> On Wed, Jan 27, 2016 at 3:02 AM, wb6bnq >
>> wrote:
>>
>> > Hi Mike,
>> >
>> > The element that you are missing is the impedance.  When you look at the
>> > common formula it refers to a ratio of power or voltage and the impedance
>> > is left out with the understanding that the impedance is equal for each
>> > power or voltage in the ratio.  The actual formula (for power) is DB =
>> 10 X
>> > log10 ( E1^2 / R ) / ( E2^2 / R ).  Hint   Power P = E^2 / R.
>> >
>> > In the RF world that impedance is 50 Ohms and ZERO DBm(illiwatts) is ONE
>> > milliwatt into 50 Ohms which is 0.223606797749979 Vrms.
>> >
>> > In the audio world the reference impedance is 600 Ohms.  So ZERO DBu is
>> > One milliwatt into 600 Ohms which is 0.7745966692414834 Vrms.  More
>> > commonly referred to as 0.775 Vrms.
>> >
>> > As for your GPS questions, I will leave that up to others to answer.
>> >
>> > BillWB6BNQ
>> >
>> >
>> > time...@metachaos.net  wrote:
>> >
>> > Hi,
>> >>
>> >> I am a newbie to this list. I have downloaded the archives and read
>> about
>> >> 5,000 of the past messages. I plan on building my own GPSDO, probably
>> >> using a
>> >> LEA-6T (but LEA-7T or LEA-M8T would be good if I can find one
>> >> affordably). I
>> >> have a MTI 260 on order (although it could wind up being a 261 since
>> they
>> >> all
>> >> appear to ship one or the other randomly).
>> >>
>> >> Currently, my resources include a DMM (well, a couple) and soldering /
>> >> desoldering stations and quite a few tools. I also have an oscilloscope
>> >> that I
>> >> am currently repairing - a 400Mhz Tektronix 2465BCT analog scope. I am
>> >> waiting
>> >> on the final parts from Mouser. Once that is done I need to get it
>> >> calibrated.
>> >> All of that will probably take me another month. I also need to finish
>> >> fixing
>> >> my cassette deck - and then to finish writing a special recording
>> program
>> >> to
>> >> use raw device drivers to get around the fact that Windows is not real
>> >> time. I
>> >> interrupted that project to work on the scope.
>> >>
>> >> In the meantime, I am reading the time-nuts messages (and lots of other
>> >> things) to gather information and ideas about how I am going to do this
>> >> and
>> >> generally to learn more.
>> >>
>> >> So, I have some questions. Let me tell you a bit about me, so that you
>> >> know
>> >> the context and my limitations. I am a retired programmer. I wrote just
>> >> about
>> >> everything including device drivers, operating systems, utilities,
>> >> various AI
>> >> programs, telephone systems, compilers, encryption, web applications and
>> >> much
>> >> more. If I need to throw 50,000 LOC at a project, no problem. I have
>> used
>> >> many
>> >> languages including quite a few different assembly languages (I have
>> also
>> >> written an assembler). I consider myself a mathematician / programmer,
>> >> although I haven't really needed Calculus or Differential Equations for
>> >> decades, so I am pretty rusty in that area. I do more work in formal
>> logic
>> >> than higher mathematics. But, I THINK like a mathematician. Formalism
>> and
>> >> abstraction come naturally to me.
>> >>
>> >> During my career I also helped to debug hardware during S-100 days. I
>> have
>> >> sporadically messed with electronics off and on, informally, with no
>> >> education
>> >> in the area. Now that I am retired (and have more time, but less money -
>> >> it IS
>> >> a zero sum game!), I am trying to learn more about electronics and start
>> >> doing
>> >> hardware projects. I have never been into model building or anything
>> >> similar,
>> >> so my construction skills are lacking. I understand a lot of things in
>> >> theory,
>> >> but practice still eludes me. For example, knowing a part exists or
>> >> determining which of 10,000 apparently identical parts is the "right"
>> >> choice.
>> >> It can hours or even days to find the "right" connector. In many cases,
>> >> the
>> >> names or descriptions are 

Re: [time-nuts] Newbie questions

[Attila Kinali]

Moin,

As no-one seems to want to answer the GPS related questions


On Tue, 26 Jan 2016 19:04:10 -0500
time...@metachaos.net wrote:

> 
> Paradoxically, I have no interest in time. As in time of day, day of week,
> etc.. I have never had a job where I got to work on time. My philosophy has
> always been "go to bed when sleepy, get up when not". I was notorious in high
> school for only showing up on test day. But, I am interested in being able to
> timestamp events accurately and in measuring time (and other things). I am
> also interested in how a very accurate frequency source can be used in
> other applications and test instruments. That brings me to my desire to build
> a GPSDO and my questions.

I have wirtten a couple of mails with references to popular GPSDO's
a couple of times in the past. You might want to have a look at them
and the discussions they were in:

https://www.febo.com/pipermail/time-nuts/2012-March/064873.html
https://www.febo.com/pipermail/time-nuts/2013-June/077368.html


> I have also been researching GPS antennas. From what I can see there are two
> basic types - the flat puck and the helical. 

There are actually many more, but the cross dipole, the spiral antenna
and the two you mentioned are by far the most popular ones.


> I have not seen anything to
> distinguish the two types based on performance or usage or to indicate that
> one or the other might be better for GPS timing.

What makes good antennas and what not is actually not that easy to define.
There was a discussion on this last spring. look for
"Important parameters for a GPS/GNSS antenna" in the archives.

> However, I have seen "GPS
> Timing Reference Antennas" advertised. Most or all of those appear to be
> helical. But, I have not seen anything that specifies the difference between 
> an active GPS antenna and an active GPS Timing Reference Antenna.

>1. What is the difference between a "normal" GPS antenna and a GPS Timing
>   Reference antenna? What features are of interest?

The timing reference antennas are usually build by manufacturers with the
intended use for high precision instruments. Either timing or geodetic survey.
Their parameters are more strictly controlled, they have (usually) a more
stable phase center and some of them are also dual band (L1/L2).

Unless you need sub-ns stability and accuracy or have a dual band receiver,
go for a standard antenna.

 
>2. Is there anything extra needed besides a GPS antenna to enable the use
>   of WAAS or other services? Apparently the ubolt receivers can make use
>   of some of that, but it is not clear what is needed to provide that
>   information to them, or if they just pick it up automatically using a
>   standard GPS antenna.

I am not sure what the LEA modules need to active WAAS/EGNOS/etc, it's
probably listed under one of the commands in the protocol reference.

You don't need any special antenna for those, as these augmentation
services use the same frequency as L1 GPS.

> Also, from what I have read, using carrier phase for timing is potentially
> more accurate by a couple orders of magnitude. Are there any GPS timing
> receivers available that use carrier phase? 

Yes, but they are darn expensive.

> Or use both L1 and L2 for increased accuracy? 

Yes, but again, expensive.

> I see that the ubolt receivers can report some carrier
> phase information, but that doesn't appear to translate to increased accuracy.

If anything, it would lead to higher precision ;-)

The reason why carrier phase tracking does not lead to large improvements
is because most receivers are single frequency receivers which cannot
directly calculate the ionospheric corrections. Thus they have to rely
on predictions send out by the GPS satellites (and by WAAS/EGNOS).
But even with those predictions, the ionospheric terms will dominate
the error. Thus there is very little gain from using carrier phase
tracking over code phase only tracking for an L1 only receiver.

> And the LEA M8T use dual channels, but don't appear to mix GPS and GLASNOS to
> improve accuracy. Do any receivers do that?

I did not have a look at the M8T yet, so i cannot answer this.
I am pretty sure that there are dual system timing receivers out there.


>  I suspect that building a GPS
> receiver is probably more complex than can be easily handled by an amateur so
> I am most likely restricted by available receivers.

Not really. I know of three people on this mailinglist who are
doing exactly this. It is just a lot of work and takes a lot of time.
The basics of a GPS receiver can be taught in an afternoon and would
enable you to build your own. But, doing it right and and time-nut
grade, with support for more than just L1 C/A requires quite a bit
more understanding and even more time.


> I have also read, more than once, statements in this forum that something or
> another could be had for some low, low price so why build it yourself? I think
> that there are several 

Re: [time-nuts] Newbie questions

[timenut]

Bob, et. al.,

Thanks for the advice and information. That has helped a lot in closing some
holes and gives me a lot to consider. I am continuing to research and learn,
this is not a short term project as in building it this week or month. I need
to learn and work up to the full project. I will probably start small with
pieces and gather what equipment I can. Like many of my projects, this one
will probably have multiple sub-projects. Especially if I manage to snag test
equipment that needs repair.

Regrettably, the 260 was ordered from China, there were none from the US when
I ordered. I did know that it would be a crap shoot, but for $26 it was
something I could get now. I might even be lucky!

I am planning on including sawtooth correction in hardware. But, I have a good
bit to learn for that. It appears to be fairly simple given your processor
reads the sawtooth correction from the GPS receiver and sets up a programmable
delay for each cycle.

I have a dozen pieces floating in my head, I am certain I will be back for
more advice.

Thanks again.


Mike

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Re: [time-nuts] Newbie questions

[wb6bnq]

Hi Mike,

The element that you are missing is the impedance.  When you look at the 
common formula it refers to a ratio of power or voltage and the 
impedance is left out with the understanding that the impedance is equal 
for each power or voltage in the ratio.  The actual formula (for power) 
is DB = 10 X log10 ( E1^2 / R ) / ( E2^2 / R ).  Hint   Power P = E^2 / R.


In the RF world that impedance is 50 Ohms and ZERO DBm(illiwatts) is ONE 
milliwatt into 50 Ohms which is 0.223606797749979 Vrms.


In the audio world the reference impedance is 600 Ohms.  So ZERO DBu is 
One milliwatt into 600 Ohms which is 0.7745966692414834 Vrms.  More 
commonly referred to as 0.775 Vrms.


As for your GPS questions, I will leave that up to others to answer.

BillWB6BNQ


time...@metachaos.net wrote:


Hi,

I am a newbie to this list. I have downloaded the archives and read about
5,000 of the past messages. I plan on building my own GPSDO, probably using a
LEA-6T (but LEA-7T or LEA-M8T would be good if I can find one affordably). I
have a MTI 260 on order (although it could wind up being a 261 since they all
appear to ship one or the other randomly).

Currently, my resources include a DMM (well, a couple) and soldering /
desoldering stations and quite a few tools. I also have an oscilloscope that I
am currently repairing - a 400Mhz Tektronix 2465BCT analog scope. I am waiting
on the final parts from Mouser. Once that is done I need to get it calibrated.
All of that will probably take me another month. I also need to finish fixing
my cassette deck - and then to finish writing a special recording program to
use raw device drivers to get around the fact that Windows is not real time. I
interrupted that project to work on the scope.

In the meantime, I am reading the time-nuts messages (and lots of other
things) to gather information and ideas about how I am going to do this and
generally to learn more.

So, I have some questions. Let me tell you a bit about me, so that you know
the context and my limitations. I am a retired programmer. I wrote just about
everything including device drivers, operating systems, utilities, various AI
programs, telephone systems, compilers, encryption, web applications and much
more. If I need to throw 50,000 LOC at a project, no problem. I have used many
languages including quite a few different assembly languages (I have also
written an assembler). I consider myself a mathematician / programmer,
although I haven't really needed Calculus or Differential Equations for
decades, so I am pretty rusty in that area. I do more work in formal logic
than higher mathematics. But, I THINK like a mathematician. Formalism and
abstraction come naturally to me.

During my career I also helped to debug hardware during S-100 days. I have
sporadically messed with electronics off and on, informally, with no education
in the area. Now that I am retired (and have more time, but less money - it IS
a zero sum game!), I am trying to learn more about electronics and start doing
hardware projects. I have never been into model building or anything similar,
so my construction skills are lacking. I understand a lot of things in theory,
but practice still eludes me. For example, knowing a part exists or
determining which of 10,000 apparently identical parts is the "right" choice.
It can hours or even days to find the "right" connector. In many cases, the
names or descriptions are completely meaningless. That all appears to be an
experience related issue, so I will (hopefully) overcome that in time.

I have no problem with soldering / desoldering, but I haven't designed or
built my own PCB yet. I have designed / redesigned some minor circuits,
especially on the power supply side. I can follow schematics reasonably well,
but I am not comfortable with Eagle or other PCB layout programs. Every time
I have tried one of those programs, half of the parts I needed were not
available. I have started using TinyCAD which is much easier to use. So, I
have a lot to learn. But, that is basically what I do, all day, every day. I'm
the type of person that gets bored easily and quickly. As #5 said "more input,
more input"!   6.02059991327962

Paradoxically, I have no interest in time. As in time of day, day of week,
etc.. I have never had a job where I got to work on time. My philosophy has
always been "go to bed when sleepy, get up when not". I was notorious in high
school for only showing up on test day. But, I am interested in being able to
timestamp events accurately and in measuring time (and other things). I am
also interested in how a very accurate frequency source can be used in
other applications and test instruments. That brings me to my desire to build
a GPSDO and my questions.

I understand the logarithmic scaling used for voltage and power. I even
understand why voltage uses a multiplier of 20 and power a multiplier of 10.
It makes sense when working with a wide range of values. 

Re: [time-nuts] Newbie questions

[Bill Byrom]

Hi, MIke. I used the university CDC6400/6600 supercomputer while in engineering 
school with punch cards or Teletypes and was familiar with S-100 vintage 
equipment. Somewhere I may still have a MIcrosoft BASIC pre MS-DOS (HDOS or 
CP/M) looseleaf manual. I haven't retired yet, but have been an Application 
Engineer at Tektronix for nearly 30 years. So I can appreciate your mindset. 
I'm going to only answer two of your questions:

1. What is the zero value for voltage and watts using logarithmic
   scaling   (at least as used here)? Is there actually a consistent
   underlying value   across all applications?

2. Why use it for specifying voltage or power in a limited range? Why
   not   just say that the output is 1.0v rms or 0.7v, or that it uses
   50mW? There   does not appear to be any actual advantage to using a
   logarithmic scale   for a small range of values - and 1mV to 1kV IS a
   small range.   Especially when you have to convert the logarithmic
   value to a "real"   value to actually do anything with it.

RF and audio (including telephone) types have used logarithmic (dB)
units for many decades. There is often a need to discuss thermal noise
levels and transmitter power levels in the same circuit, which can lead
to very large voltage and power ratios. It's common to need to relate
voltages over a 10^10 range and powers over a 10^20 range
(1:0.0001). Engineers and scientists like to use numeric
values which are easier to work with. You wouldn't want to specify a
hard drive size as 1,000,000,000,000 bytes but as 1 TB (ignoring the
power of 2 vs power of 10 issue). So we use "engineering units" (powers
of 1,000) for frequency (kHz, MHz, GHz, THz), voltage (pV, nV, uV, mV,
V, kV, MV, GV).

RF applications are more naturally dealt with in terms of power. The
noise generated in a resistor due to thermal agitation (Johnson-Nyquist
noise) is P = kTB, where P = power in watts, k = Boltzmanns constant
(1.28 x 10^-23 J/K), T = absolute temperature in Kelvins, and B is the
measurement bandwidth in Hertz. Many RF components are rated by power
dissipation. Historically it's been much easier to measure RF signals
levels by measuring thermal changes due to signal power.

The very large dynamic range required for characterizing sound and
telephone line levels and relating them to human perceived level change
led to the definition of the Bel (power ratio of 10, named for Alexander
Graham Bell). The decibel (1/10 Bel) is the logarithmic unit which is
used in practice. The noise delivered by a resistor to a matched load at
room temperature and normalized to a 1 Hz measurement bandwidth is about
-174 dBm/Hz.

The "m" in "dBm" stands for 1 mW (milliwatt). So 0 dBm = 1 mW. You
should read "dBm" as "decibels relative to 1 milliwatt". Since most
power levels in RF equipment tend to be within a couple of orders of
magnitude below or above a milliwatt, dBm is the main unit used for RF
equipment which can fit on your lab bench. In some cases it's convenient
to use logarithmic voltage units, and the common units are dBuV
(decibels relative to 1 microvolt), dBmV (decibels relative to 1
millivolt), or dBV (decibels relative to 1 volt). But except for cable
television and a few other applications (including noise levels at low
audio frequencies), dBm rules the RF world.

You are correct that linear non-logarithmic units work well when a small
range of values are being used. Amateur Radio handheld transmitters have
power ratings usually given in linear watts (100 mW, 1 W, 3 W, 5 W,
etc.). A HF (high frequency 3-30 MHz) transmitter may have an output
power meter marked in linear units of Watts. But the received signal
strength meter is marked in logarithmic units, since with an automatic
gain control the receiver dynamic range is many orders of magnitude too
large to be shown with linear units.

You happen to have test equipment which measures linear units. Many
voltmeters designed to measure audio levels are calibrated in dBmV. Most
RF signal level measurement instruments (power meters and spectrum
analyzers) are usually used with dB or dBm scaling. Since the ratio of
RF signals is often the main measurement of interest (such as harmonic
or intermodulation level), spectrum analyzers are usually set up with a
a variable full scale value (reference level) and a dB ratio vertical
scale. The horizontal scale of a spectrum analyzer is usually linear
frequency, but in many cases can be changed to logarithmic frequency.

Modern oscilloscopes (those made in the past 20 years) digitize the
voltage waveform, and they can easily show RMS voltage and even power
levels. For many RF measurements the oscilloscope uses an FFT to create
a spectrum display scaled in dBm. A DMM is not used to measure RF
levels, but RF power meters directly display dBm power, as also used by
spectrum analyzers.

So the reason that your test equipment doesn't produce measurements in
the same units commonly used by RF engineers is that you 

Re: [time-nuts] Newbie questions

[Bob Camp]

Hi

Ok, so let me answer the questions you *should* have asked:

(They are in no particular order. Number 3 probably should come first)

1) Is the gear I have enough to do this project? 

No, you will need some sort of frequency  / time standard. An atomic
clock of some sort is pretty much a minimum. You probably also need
a working GPSDO (or set of them) for comparison as well. You will also 
need a working / modern precision counter that will give you data down 
in the < 100 ps range. 

2) How will this ultimately be built? 

At the very least, you will be building this with surface mount devices. 
If it’s a scratch build, you will be dealing with fine pitch parts. That gets
you into a whole bunch of gear. It also gets you into a very real “is this 
fun or not” sort of question. 

3) What *is* the goal? 

"I’m going to make dinner” is the start of a process. It’s not enough of a 
goal to accomplish the task. Starting the task with a general objective is fine.
It does need to be refined a bit before you go much further.  

Is this what most of us would call a GPSDO (self contained box) or is it
something with a PC in the middle of it? 

Is this an OCXO based “precision” device or is it something more simple?

Is a pure software solution good enough?

Each of those decisions (and that’s by no means a full list) will send you off 
in a very different direction. 

4) How long is this likely to take?

Best guess based on the others who have done the same thing - several 
years. 

5) How much is this likely to cost?

If done the way others have done it, several thousand dollars up to 
quite a bit more than that. 

6) How much research is involved?

Quite a bit. The information you need is scattered all over the place. Figure
that you likely will read at least several hundred papers. There is a whole 
statistical language that is unique to these gizmos. This is *not* a follow a 
set recipe sort of project. 

Lots of fun !!!

Bob




> On Jan 26, 2016, at 7:04 PM, time...@metachaos.net wrote:
> 
> Hi,
> 
> I am a newbie to this list. I have downloaded the archives and read about
> 5,000 of the past messages. I plan on building my own GPSDO, probably using a
> LEA-6T (but LEA-7T or LEA-M8T would be good if I can find one affordably). I
> have a MTI 260 on order (although it could wind up being a 261 since they all
> appear to ship one or the other randomly).
> 
> Currently, my resources include a DMM (well, a couple) and soldering /
> desoldering stations and quite a few tools. I also have an oscilloscope that I
> am currently repairing - a 400Mhz Tektronix 2465BCT analog scope. I am waiting
> on the final parts from Mouser. Once that is done I need to get it calibrated.
> All of that will probably take me another month. I also need to finish fixing
> my cassette deck - and then to finish writing a special recording program to
> use raw device drivers to get around the fact that Windows is not real time. I
> interrupted that project to work on the scope.
> 
> In the meantime, I am reading the time-nuts messages (and lots of other
> things) to gather information and ideas about how I am going to do this and
> generally to learn more.
> 
> So, I have some questions. Let me tell you a bit about me, so that you know
> the context and my limitations. I am a retired programmer. I wrote just about
> everything including device drivers, operating systems, utilities, various AI
> programs, telephone systems, compilers, encryption, web applications and much
> more. If I need to throw 50,000 LOC at a project, no problem. I have used many
> languages including quite a few different assembly languages (I have also
> written an assembler). I consider myself a mathematician / programmer,
> although I haven't really needed Calculus or Differential Equations for
> decades, so I am pretty rusty in that area. I do more work in formal logic
> than higher mathematics. But, I THINK like a mathematician. Formalism and
> abstraction come naturally to me.
> 
> During my career I also helped to debug hardware during S-100 days. I have
> sporadically messed with electronics off and on, informally, with no education
> in the area. Now that I am retired (and have more time, but less money - it IS
> a zero sum game!), I am trying to learn more about electronics and start doing
> hardware projects. I have never been into model building or anything similar,
> so my construction skills are lacking. I understand a lot of things in theory,
> but practice still eludes me. For example, knowing a part exists or
> determining which of 10,000 apparently identical parts is the "right" choice.
> It can hours or even days to find the "right" connector. In many cases, the
> names or descriptions are completely meaningless. That all appears to be an
> experience related issue, so I will (hopefully) overcome that in time.
> 
> I have no problem with soldering / desoldering, but I haven't designed or
> built my own PCB yet. I have designed / redesigned some 

Re: [time-nuts] Newbie questions

[Jim Harman]

Another benefit of using dB vs Watts or Volts is that systems often consist
of a chain of elements with gains and losses. Working with gains and losses
in dB lets you calculate the signal level at any point along the way and
the system gain by adding and subtracting rather than multiplying and
dividing.

On Wed, Jan 27, 2016 at 3:02 AM, wb6bnq  wrote:

> Hi Mike,
>
> The element that you are missing is the impedance.  When you look at the
> common formula it refers to a ratio of power or voltage and the impedance
> is left out with the understanding that the impedance is equal for each
> power or voltage in the ratio.  The actual formula (for power) is DB = 10 X
> log10 ( E1^2 / R ) / ( E2^2 / R ).  Hint   Power P = E^2 / R.
>
> In the RF world that impedance is 50 Ohms and ZERO DBm(illiwatts) is ONE
> milliwatt into 50 Ohms which is 0.223606797749979 Vrms.
>
> In the audio world the reference impedance is 600 Ohms.  So ZERO DBu is
> One milliwatt into 600 Ohms which is 0.7745966692414834 Vrms.  More
> commonly referred to as 0.775 Vrms.
>
> As for your GPS questions, I will leave that up to others to answer.
>
> BillWB6BNQ
>
>
> time...@metachaos.net wrote:
>
> Hi,
>>
>> I am a newbie to this list. I have downloaded the archives and read about
>> 5,000 of the past messages. I plan on building my own GPSDO, probably
>> using a
>> LEA-6T (but LEA-7T or LEA-M8T would be good if I can find one
>> affordably). I
>> have a MTI 260 on order (although it could wind up being a 261 since they
>> all
>> appear to ship one or the other randomly).
>>
>> Currently, my resources include a DMM (well, a couple) and soldering /
>> desoldering stations and quite a few tools. I also have an oscilloscope
>> that I
>> am currently repairing - a 400Mhz Tektronix 2465BCT analog scope. I am
>> waiting
>> on the final parts from Mouser. Once that is done I need to get it
>> calibrated.
>> All of that will probably take me another month. I also need to finish
>> fixing
>> my cassette deck - and then to finish writing a special recording program
>> to
>> use raw device drivers to get around the fact that Windows is not real
>> time. I
>> interrupted that project to work on the scope.
>>
>> In the meantime, I am reading the time-nuts messages (and lots of other
>> things) to gather information and ideas about how I am going to do this
>> and
>> generally to learn more.
>>
>> So, I have some questions. Let me tell you a bit about me, so that you
>> know
>> the context and my limitations. I am a retired programmer. I wrote just
>> about
>> everything including device drivers, operating systems, utilities,
>> various AI
>> programs, telephone systems, compilers, encryption, web applications and
>> much
>> more. If I need to throw 50,000 LOC at a project, no problem. I have used
>> many
>> languages including quite a few different assembly languages (I have also
>> written an assembler). I consider myself a mathematician / programmer,
>> although I haven't really needed Calculus or Differential Equations for
>> decades, so I am pretty rusty in that area. I do more work in formal logic
>> than higher mathematics. But, I THINK like a mathematician. Formalism and
>> abstraction come naturally to me.
>>
>> During my career I also helped to debug hardware during S-100 days. I have
>> sporadically messed with electronics off and on, informally, with no
>> education
>> in the area. Now that I am retired (and have more time, but less money -
>> it IS
>> a zero sum game!), I am trying to learn more about electronics and start
>> doing
>> hardware projects. I have never been into model building or anything
>> similar,
>> so my construction skills are lacking. I understand a lot of things in
>> theory,
>> but practice still eludes me. For example, knowing a part exists or
>> determining which of 10,000 apparently identical parts is the "right"
>> choice.
>> It can hours or even days to find the "right" connector. In many cases,
>> the
>> names or descriptions are completely meaningless. That all appears to be
>> an
>> experience related issue, so I will (hopefully) overcome that in time.
>>
>> I have no problem with soldering / desoldering, but I haven't designed or
>> built my own PCB yet. I have designed / redesigned some minor circuits,
>> especially on the power supply side. I can follow schematics reasonably
>> well,
>> but I am not comfortable with Eagle or other PCB layout programs. Every
>> time
>> I have tried one of those programs, half of the parts I needed were not
>> available. I have started using TinyCAD which is much easier to use. So, I
>> have a lot to learn. But, that is basically what I do, all day, every
>> day. I'm
>> the type of person that gets bored easily and quickly. As #5 said "more
>> input,
>> more input"!   6.02059991327962
>>
>> Paradoxically, I have no interest in time. As in time of day, day of week,
>> etc.. I have never had a job where I got to work on 

Re: [time-nuts] Newbie

[Gary Woods]

On Tue, 18 Aug 2015 10:10:04 -0500, you wrote:

There's a good search utility at 
https://www.mail-archive.com/time-nuts@febo.com/

Dave:

Thanks for this; I'm searching for an earlier version of u-center, since
the current one doesn't work on XP, and the ublox site doesn't have earlier
versions.
I just got a Chinese GPSDO to clock a late 70s-vintage counter kit I built
when dinosaurs walked the land, and I'm trying to find something to talk to
it.  Clearly, it's _way_ better than the TCXO that came with it, or the
Janel Labs oven that aged beyond adjustment range!
Anyway, thanks for the pointer.  I'll play for a bit before posting to the
list.


-- 
Gary Woods O- K2AHC   Public keys at home.earthlink.net/~garygarlic, or get 
0x1D64A93D via keyserver
fingerprint =  E2 6F 50 93 7B C7 F3 CA  1F 8B 3C C0 B0 28 68 0B
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Re: [time-nuts] Newbie

[Gary Woods]

The previous was meant to go to the nice person who pointed me to some
search option.
Humble apologies.
It wasn't even my first misteak of the day, but the others were offline.

-- 
Gary Woods O- K2AHC   Public keys at home.earthlink.net/~garygarlic, or get 
0x1D64A93D via keyserver
fingerprint =  E2 6F 50 93 7B C7 F3 CA  1F 8B 3C C0 B0 28 68 0B
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Re: [time-nuts] Newbie

[Hal Murray]

garygar...@earthlink.net said:
 Before I embarrass myself in public (again), is there an archive search for
 the time nuts list? I'll lurk for a while before posting...

Google works pretty well.  Just add time-nuts to your search string.  If 
that gets too much duplication from sites that clone the list, add something 
like site:febo.com


The headers of each message to the list have a pointer to the archives:
  List-archive: http://www.febo.com/pipermail/time-nuts/
There is also a link on the signup page.

That will get you to a table where you can see the subjects by month at a 
time which sometimes works if you know the message you are looking for is 
recent, or you have the date for a message and want to see the rest of the 
thread.



-- 
These are my opinions.  I hate spam.



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Re: [time-nuts] Newbie

[Ian Stirling]

On 08/18/2015 05:33 PM, Hal Murray wrote:

 Google works pretty well.  Just add time-nuts to your search string.  If 
 that gets too much duplication from sites that clone the list, add something 
 like site:febo.com

  Thank you Tom and others in this thread.
I was considering posting something but found the search information
useful and that my proposed posting has been discussed previously.

  I like to use startpage.com as my search engine:
it strips identification and passes the search to google and seems
to return more focused and less superfluous results.

Ian, G4ICV, AB2GR
--
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Re: [time-nuts] Newbie

[Tom Van Baak]

Hi Gary,

Yes, useful information about the list: 
http://leapsecond.com/time-nuts.htm#search

/tvb

- Original Message - 
From: Gary Woods garygar...@earthlink.net
To: time-nuts@febo.com
Sent: Tuesday, August 18, 2015 6:32 AM
Subject: [time-nuts] Newbie


 Before I embarrass myself in public (again), is there an archive search for
 the time nuts list? I'll lurk for a while before posting...
 
 
 -- 
 Gary Woods AKA K2AHC- PGP key on request, or at home.earthlink.net/~garygarlic
 Zone 5/4 in upstate New York, 1420' elevation. NY WO G

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Re: [time-nuts] Newbie

[Dave M]

There's a good search utility at 
https://www.mail-archive.com/time-nuts@febo.com/


Cheers,
Dave M

Gary Woods wrote:

Before I embarrass myself in public (again), is there an archive
search for the time nuts list? I'll lurk for a while before posting...




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Re: [time-nuts] Newbie question

[Mike Monett]

Hi Time-Nuts:
Not sure what the protocol is here but I'll just jump in.

I've just purchased an HP53310a modulation domain analyzer. Most you already 
know that these amazing instruments are basically a TIC with a graphic 
display of frequency vs time. I've always wanted one to record PLL settling 
time. I also know they are pretty non-intuitive to setup and use. Now that I 
have one I'd like to connect with someone that has experience using them.

Anyone?

Best Regards to the group.

Stuart Rumley

[...]

You can monitor the VCO DC error voltage to look for risetime and ringing
problems. To monitor settling time, trigger the scope on the frequency
switch, delay out to the desired region, and display the reference and VCO
signals to the phase detector added together. If you use a triggered delay
you can step from one cycle to the next and watch the signals align
themselves.

Depending on the skill of the designer, the PLL may exhibit jumps in phase
during settling due to crosstalk, or many other kinds of nasties at
different points in the phase relationship. If he did not monitor the PLL
settling during development, there will likely be things you may not like.

Bottom line is I much prefer looking at the VCO DC error and the inputs to
the phase detector rather than trying to investigate these problems with
the 53310A. The actual waveforms give a lot more information to work with.

Mike Monett

One thing I did not mention is you can see things in the VFO DC error and
phase jumps that do not show up in the 53310A. These can be serious and
need to be addressed. 

Since there are many ways of making better measurements than the 53310A can
provide, I will sell my unit on eBay. The prices can reach $3,795.00, but I
will be happy with much less. Here are the current listings:

http://www.ebay.com/sch/i.html?_from=R40_sacat=0_nkw=hp+53310a_sop=16

One thing that is very important is proper packaging for shipment. Here are
some urls that discuss how to package heavy instruments for shipment. Sorry
for the wrap:

http://www.prc68.com/I/Pack.shtml
http://gemmary.blogspot.ca/2007/07/how-to-pack-expensive-antique.html
http://www.astromart.com/articles/article.asp?article_id=63
http://www.ups.com/content/us/en/resources/ship/packaging/guidelines/how_to.html
http://www.ups.com/content/us/en/resources/ship/packaging/guidelines/how_to2.html
http://www.ups.com/content/us/en/resources/ship/packaging/guidelines/how_to3.html
http://www.ups.com/content/us/en/resources/ship/packaging/guidelines/how_to4.html
http://www.ups.com/content/us/en/resources/ship/packaging/guidelines.html
http://www.ups.com/content/us/en/resources/ship/packaging/weight_size.html
http://www.prc68.com/I/SWCC2.shtml#mickiecat1
http://cp.literature.agilent.com/litweb/pdf/5991-0392EEE.pdf

In addition, for those who are terrified by having to use Paypal due to the
possibility of having your account and funds locked, it is no longer a
requirement to use Paypal on eBay. You can use various credit card services
such as Merchantinc, and specify on your eBay page that you do not accept
Paypal.

https://www.merchantinc.com/

For example, see the Payments: Visa/MasterCard, Discover entry on 

http://cgi.ebay.com/161599376831

No Paypal. Problem solved.

So get out that old scope and microwave attenuator and make some money!

Mike Monett
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Re: [time-nuts] Newbie question

[Mike Monett]

Hi Time-Nuts:
Not sure what the protocol is here but I'll just jump in.

I've just purchased an HP53310a modulation domain analyzer. Most you already 
know that these amazing instruments are basically a TIC with a graphic display 
of frequency vs time. I've always wanted one to record PLL settling time. I 
also know they are pretty non-intuitive to setup and use. Now that I have one 
I'd like to connect with someone that has experience using them.

Anyone?

Best Regards to the group.

Stuart Rumley

650-369-0575

Hi Stuart,

Also contact Joe Geller, who was active on time-nuts some years ago, and who 
wrote the ultimate 53310a reference page: 
http://www.gellerlabs.com/hp53310a.htm

/tvb

One thing that Joe Geller doesn't mention is the fierce leakage from the
power transformer. You may not notice it on a modern scope with LCD
display, but my 53310A spewed so much field that it demolished the display
on a Tek 2467B sitting nearby. I had to move the 53310A to a separate
bench. Why it didn't seem to bother its own internal crt is a complete
mystery. I'm sure it would bother a Rubidium.

I found the 53310A to be a lot less useful than expected. There are other
ways of making measurements that are easier and more accurate. Now, it just
sits in a corner gathering dust.

As far as measuring the PLL settling, you will need an external reference
that you can frequency modulate. Depending on your requirements, it could
be something simple like an RC oscillator with lots of phase noise, or two
low phase noise OCXO's at slightly different frequencies with a digital
mixer detecting the phase alignment and switching the signal to your PLL
from one OCXO to the other.

You can monitor the VCO DC error voltage to look for risetime and ringing
problems. To monitor settling time, trigger the scope on the frequency
switch, delay out to the desired region, and display the reference and VCO
signals to the phase detector added together. If you use a triggered delay
you can step from one cycle to the next and watch the signals align
themselves.

Depending on the skill of the designer, the PLL may exhibit jumps in phase
during settling due to crosstalk, or many other kinds of nasties at
different points in the phase relationship. If he did not monitor the PLL
settling during development, there will likely be things you may not like.

Bottom line is I much prefer looking at the VCO DC error and the inputs to
the phase detector rather than trying to investigate these problems with
the 53310A. The actual waveforms give a lot more information to work with.

Mike Monett
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Re: [time-nuts] Newbie question about thunderbolts

[James Tucker]

Hi, Paul. Glad to see you made it here. For the time-nuts; Paul and I
have spoken about these issues, and I have had similar experience. The
only thing I would add is the the spikes to seem to occur less
frequently with a better antenna placement, but when they start to
cluster, they fire off one every two or three seconds, sometimes
faster.

JimT

On Wed, Feb 27, 2013 at 2:08 PM, Paul Berger phb@gmail.com wrote:

 Hello all:

 I am an electronic technician with 30+ years experience fixing
 computers.   In my spare time I like to play with old computers and
 electronics.  Recently I got bit by the precision timing bug, partially
 after running across the wonderful leapsecond.com site, which lead me
 here.   First I got  a FE-5680A, then after reading some of the archives
 here I bought a Nortel / Trimble 45000   GPSDO and still later a used
 Thunderbolt-E.

 My main interest in these devices at this time is for a accurate bench
 top frequency source, however I do have a 59309A running off of each of
 the GPSDOs.  I am wondering if they will drift apart, but I suspect I
 will need to wait a long time to see evidence of that. I set them
 simultaneously by setting them both to the same GPIB address and
 connecting them to the same bus on my HP-86B, this works well for
 setting them but I have to remember to disconnect one or change the
 address on one before I try to read them.

 MY question concerns the thunderbolt-E, I have been using LH to monitor
 both of the GPSDOs and was quite surprised to see that the Nortel 45000
 seems to perform much better than the thunderbolt-E, I thought that the
 E being a newer device it would perform better.  I will admit that I
 have a much less than ideal antenna setup however the antenna location
 is the same for both devices, they are  only a couple feet apart.  The
 antenna's are a Trimble magnet mount antenna and a the dome antenna that
 came with the thunderbolt-E kit. Initially I had the magnet mount
 attached to the Nortel and the dome antenna attached to the E, but I
 have now swapped antennas but it has not made any difference , and I am
 beginning to wonder if my E is in fact defective.  I have been in
 contact with one other person who has an E and his experiences have been
 similar to mine, even though he has a much better antenna setup, so I
 would like to ask if there is anyone else out there with an E, and ask
 the group for comments on what I am seeing.

 My observations have been that the 10MHz is not very stable, on LH I
 will see relatively large spikes  in the DAC voltage that of course
 impacts the 10MHZ, I had it connected to my 5316A counter that was
 running with the FE-5680A as a timebase, with a 10 second gate time and
 logging counts with my 86B and I was seeing excursions og over 100Hz
 which I guess percentage wise is not huge but I do not see anything like
 that on the Nortel.  Now some of these excursions do occur when there
 are satellite switches, and if they all occurred coincident to satellite
 switches I would mark it up to my crummy antenna arrangement, but they
 don't they occur even when the satellite tracking is stable and often
 come in groups of several transition first positive followed by an equal
 transition in the negative direction. There is also a constant
 chatter of about 100uV on the DAC line as reported by LH which also
 translates to noise on the OSC and PPS lines, my technician sense thinks
 that looks like power supply noise, but I have not looked under the hood
 yet.   One really annoying thing I have noticed is the E reports having
 saved my location, however it apparently has not so every time it resets
 for whatever reason it goes into a self survey, which because of my less
 than ideal antenna setup usually takes some time to complete, even a
 warm reset resulted in it losing it location and entering self survey.



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Re: [time-nuts] Newbie question about thunderbolts

[John Miles]

Sounds like a bad OCXO.  The crystal frequency jumps slightly, and the
disciplining loop then has to compensate by steering the DAC  voltage
through the loop filter.  If that's the problem it may get better if you
leave it running for a few more weeks.

The smoking gun is the attack/decay characteristic of the DAC adjustment.
At least in theory, no issues on the GPS side of the loop should result in a
fast leading edge at the DAC. 

I haven't seen any Thunderbolts with genuinely bad OCXOs yet, although some
of them are definitely better than others.  The Thunderbolt-E, however, is a
very different model than the ones that are normally found on eBay.  Almost
everything you hear about a Thunderbolt refers to the older non-E version.


I've heard (but can't exactly cite) that the Thunderbolt E models were a
reduced-cost, higher-volume product.  If that's true, you can assume that
they don't use the same OCXOs, because those OCXOs were much better -- and
would have been more expensive -- than they had to be.  

(The Thunderbolt E should not be confused with the more common Thunderbolts
running 'E'-level firmware.)

-- john, KE5FX

 Hi, Paul. Glad to see you made it here. For the time-nuts; Paul and I
 have spoken about these issues, and I have had similar experience. The
 only thing I would add is the the spikes to seem to occur less
 frequently with a better antenna placement, but when they start to
 cluster, they fire off one every two or three seconds, sometimes
 faster.
 
 JimT
 
 On Wed, Feb 27, 2013 at 2:08 PM, Paul Berger phb@gmail.com wrote:
 
  Hello all:
 
  I am an electronic technician with 30+ years experience fixing
  computers.   In my spare time I like to play with old computers and
  electronics.  Recently I got bit by the precision timing bug, partially
  after running across the wonderful leapsecond.com site, which lead me
  here.   First I got  a FE-5680A, then after reading some of the archives
  here I bought a Nortel / Trimble 45000   GPSDO and still later a used
  Thunderbolt-E...

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Re: [time-nuts] Newbie question about thunderbolts

[Paul Berger]

I did peek inside the E not long after I got it and I do remember that 
the OXCO looks very different, it is much smaller than the one on my 
Nortel unit.  If it is the OXCO I can always source a potentially better 
OXCO and then I can have more fun playing with it.  Being a technician I 
really enjoy fixing things and seeing them work again.  One other big 
difference in the E model is it takes a single 24VDC power input and has 
a little switcher module in it to generate the voltage the GPSDO 
actually uses, this is similar to the setup on the Nortel unit, however 
it did not look to be built nearly as good.  I will give it a little 
more time and if it does not improve I will pull it out of its box and 
start to poke around inside.


Paul.

On 2/27/13 8:23 PM, John Miles wrote:

Sounds like a bad OCXO.  The crystal frequency jumps slightly, and the
disciplining loop then has to compensate by steering the DAC  voltage
through the loop filter.  If that's the problem it may get better if you
leave it running for a few more weeks.

The smoking gun is the attack/decay characteristic of the DAC adjustment.
At least in theory, no issues on the GPS side of the loop should result in a
fast leading edge at the DAC.

I haven't seen any Thunderbolts with genuinely bad OCXOs yet, although some
of them are definitely better than others.  The Thunderbolt-E, however, is a
very different model than the ones that are normally found on eBay.  Almost
everything you hear about a Thunderbolt refers to the older non-E version.


I've heard (but can't exactly cite) that the Thunderbolt E models were a
reduced-cost, higher-volume product.  If that's true, you can assume that
they don't use the same OCXOs, because those OCXOs were much better -- and
would have been more expensive -- than they had to be.

(The Thunderbolt E should not be confused with the more common Thunderbolts
running 'E'-level firmware.)

-- john, KE5FX


Hi, Paul. Glad to see you made it here. For the time-nuts; Paul and I
have spoken about these issues, and I have had similar experience. The
only thing I would add is the the spikes to seem to occur less
frequently with a better antenna placement, but when they start to
cluster, they fire off one every two or three seconds, sometimes
faster.

JimT

On Wed, Feb 27, 2013 at 2:08 PM, Paul Berger phb@gmail.com wrote:

Hello all:

I am an electronic technician with 30+ years experience fixing
computers.   In my spare time I like to play with old computers and
electronics.  Recently I got bit by the precision timing bug, partially
after running across the wonderful leapsecond.com site, which lead me
here.   First I got  a FE-5680A, then after reading some of the archives
here I bought a Nortel / Trimble 45000   GPSDO and still later a used
Thunderbolt-E...

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Re: [time-nuts] Newbie question about thunderbolts

[EWKehren]

I did get one bad one leak or pin hole aging so much that it would have run 
 out of tuning range in a month
Bert Kehren
 
 
In a message dated 2/27/2013 7:24:25 P.M. Eastern Standard Time,  
jmi...@pop.net writes:

Sounds  like a bad OCXO.  The crystal frequency jumps slightly, and  the
disciplining loop then has to compensate by steering the DAC   voltage
through the loop filter.  If that's the problem it may get  better if you
leave it running for a few more weeks.

The smoking gun  is the attack/decay characteristic of the DAC adjustment.
At least in  theory, no issues on the GPS side of the loop should result in 
a
fast  leading edge at the DAC. 

I haven't seen any Thunderbolts with  genuinely bad OCXOs yet, although some
of them are definitely better than  others.  The Thunderbolt-E, however, is 
a
very different model than  the ones that are normally found on eBay.  Almost
everything you hear  about a Thunderbolt refers to the older non-E 
version.


I've heard  (but can't exactly cite) that the Thunderbolt E models were a
reduced-cost,  higher-volume product.  If that's true, you can assume that
they don't  use the same OCXOs, because those OCXOs were much better -- and
would have  been more expensive -- than they had to be.  

(The Thunderbolt E  should not be confused with the more common Thunderbolts
running 'E'-level  firmware.)

-- john, KE5FX

 Hi, Paul. Glad to see you made it  here. For the time-nuts; Paul and I
 have spoken about these issues,  and I have had similar experience. The
 only thing I would add is the  the spikes to seem to occur less
 frequently with a better antenna  placement, but when they start to
 cluster, they fire off one every two  or three seconds, sometimes
 faster.
 
 JimT
  
 On Wed, Feb 27, 2013 at 2:08 PM, Paul Berger  phb@gmail.com wrote:
 
  Hello all:
  
  I am an electronic technician with 30+ years experience  fixing
  computers.   In my spare time I like to play  with old computers and
  electronics.  Recently I got bit by  the precision timing bug, partially
  after running across the  wonderful leapsecond.com site, which lead me
  here.First I got  a FE-5680A, then after reading some of the 
archives
   here I bought a Nortel / Trimble 45000   GPSDO and still later  a used
   Thunderbolt-E...

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Re: [time-nuts] Newbie question about thunderbolts

[Bob Camp]

Hi

An E series Thunderbolt is about 4X the size of the later Thunderbolt, 
sometimes called an E. Yes it's very confusing. 

If the OCXO is about 1 on a side and the unit is maybe 1.5 wide, then you 
have the later version of the Thunderbolt. Probably the best way to confirm 
this and eliminate the confusion would be a picture.

Bob

On Feb 27, 2013, at 7:35 PM, Paul Berger phb@gmail.com wrote:

 I did peek inside the E not long after I got it and I do remember that the 
 OXCO looks very different, it is much smaller than the one on my Nortel unit. 
  If it is the OXCO I can always source a potentially better OXCO and then I 
 can have more fun playing with it.  Being a technician I really enjoy fixing 
 things and seeing them work again.  One other big difference in the E model 
 is it takes a single 24VDC power input and has a little switcher module in it 
 to generate the voltage the GPSDO actually uses, this is similar to the setup 
 on the Nortel unit, however it did not look to be built nearly as good.  I 
 will give it a little more time and if it does not improve I will pull it out 
 of its box and start to poke around inside.
 
 Paul.
 
 On 2/27/13 8:23 PM, John Miles wrote:
 Sounds like a bad OCXO.  The crystal frequency jumps slightly, and the
 disciplining loop then has to compensate by steering the DAC  voltage
 through the loop filter.  If that's the problem it may get better if you
 leave it running for a few more weeks.
 
 The smoking gun is the attack/decay characteristic of the DAC adjustment.
 At least in theory, no issues on the GPS side of the loop should result in a
 fast leading edge at the DAC.
 
 I haven't seen any Thunderbolts with genuinely bad OCXOs yet, although some
 of them are definitely better than others.  The Thunderbolt-E, however, is a
 very different model than the ones that are normally found on eBay.  Almost
 everything you hear about a Thunderbolt refers to the older non-E version.
 
 
 I've heard (but can't exactly cite) that the Thunderbolt E models were a
 reduced-cost, higher-volume product.  If that's true, you can assume that
 they don't use the same OCXOs, because those OCXOs were much better -- and
 would have been more expensive -- than they had to be.
 
 (The Thunderbolt E should not be confused with the more common Thunderbolts
 running 'E'-level firmware.)
 
 -- john, KE5FX
 
 Hi, Paul. Glad to see you made it here. For the time-nuts; Paul and I
 have spoken about these issues, and I have had similar experience. The
 only thing I would add is the the spikes to seem to occur less
 frequently with a better antenna placement, but when they start to
 cluster, they fire off one every two or three seconds, sometimes
 faster.
 
 JimT
 
 On Wed, Feb 27, 2013 at 2:08 PM, Paul Berger phb@gmail.com wrote:
 Hello all:
 
 I am an electronic technician with 30+ years experience fixing
 computers.   In my spare time I like to play with old computers and
 electronics.  Recently I got bit by the precision timing bug, partially
 after running across the wonderful leapsecond.com site, which lead me
 here.   First I got  a FE-5680A, then after reading some of the archives
 here I bought a Nortel / Trimble 45000   GPSDO and still later a used
 Thunderbolt-E...
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Re: [time-nuts] Newbie question about thunderbolts

[Paul Berger]

Bob:

I am quite sure this is a Thunderbolt E as opposed to the E series of 
the earlier Thunderbolt, the blue label on top of the aluminum box says 
Thunderbolt E the blue Trimble box that it came in says Thunderbolt E 
Starter Kit and yes as I said below the OCXO is smaller than the one on 
my Nortel unit, it is roughly the same footprint as the Trimble 34310 
OXCO on the Nortel unit but less than half the height.  It looks just 
like the picture here on Trimble's website. 
http://www.trimble.com/timing/thunderbolt-e.aspx


Paul.

On 2/27/13 9:43 PM, Bob Camp wrote:

Hi

An E series Thunderbolt is about 4X the size of the later Thunderbolt, 
sometimes called an E. Yes it's very confusing.

If the OCXO is about 1 on a side and the unit is maybe 1.5 wide, then you 
have the later version of the Thunderbolt. Probably the best way to confirm this and 
eliminate the confusion would be a picture.

Bob

On Feb 27, 2013, at 7:35 PM, Paul Berger phb@gmail.com wrote:


I did peek inside the E not long after I got it and I do remember that the OXCO 
looks very different, it is much smaller than the one on my Nortel unit.  If it 
is the OXCO I can always source a potentially better OXCO and then I can have 
more fun playing with it.  Being a technician I really enjoy fixing things and 
seeing them work again.  One other big difference in the E model is it takes a 
single 24VDC power input and has a little switcher module in it to generate the 
voltage the GPSDO actually uses, this is similar to the setup on the Nortel 
unit, however it did not look to be built nearly as good.  I will give it a 
little more time and if it does not improve I will pull it out of its box and 
start to poke around inside.

Paul.

On 2/27/13 8:23 PM, John Miles wrote:

Sounds like a bad OCXO.  The crystal frequency jumps slightly, and the
disciplining loop then has to compensate by steering the DAC  voltage
through the loop filter.  If that's the problem it may get better if you
leave it running for a few more weeks.

The smoking gun is the attack/decay characteristic of the DAC adjustment.
At least in theory, no issues on the GPS side of the loop should result in a
fast leading edge at the DAC.

I haven't seen any Thunderbolts with genuinely bad OCXOs yet, although some
of them are definitely better than others.  The Thunderbolt-E, however, is a
very different model than the ones that are normally found on eBay.  Almost
everything you hear about a Thunderbolt refers to the older non-E version.


I've heard (but can't exactly cite) that the Thunderbolt E models were a
reduced-cost, higher-volume product.  If that's true, you can assume that
they don't use the same OCXOs, because those OCXOs were much better -- and
would have been more expensive -- than they had to be.

(The Thunderbolt E should not be confused with the more common Thunderbolts
running 'E'-level firmware.)

-- john, KE5FX


Hi, Paul. Glad to see you made it here. For the time-nuts; Paul and I
have spoken about these issues, and I have had similar experience. The
only thing I would add is the the spikes to seem to occur less
frequently with a better antenna placement, but when they start to
cluster, they fire off one every two or three seconds, sometimes
faster.

JimT

On Wed, Feb 27, 2013 at 2:08 PM, Paul Berger phb@gmail.com wrote:

Hello all:

I am an electronic technician with 30+ years experience fixing
computers.   In my spare time I like to play with old computers and
electronics.  Recently I got bit by the precision timing bug, partially
after running across the wonderful leapsecond.com site, which lead me
here.   First I got  a FE-5680A, then after reading some of the archives
here I bought a Nortel / Trimble 45000   GPSDO and still later a used
Thunderbolt-E...

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Re: [time-nuts] newbie question Thunderbolt supply

[ew]

Chris
Starting with 3.4 W used by the Tbolt my battery version burns 4.4 W.  Using a 
switcher do generate 7 V   4.8 W and running the 7805 directly from 14.5 V 
6.2.W. I use like you an IC temp sensor, two stage op amp driving a fan holding 
the backplate temp constant and total power goes up to 7.6 W since the oven has 
to work harder. T bolt, switchers and all regulators are on the other side of 
the 3/32 Alu plate. The AC switcher is not included in the power numbers. but 
is also on the plate. Plate is held at 40 C.
I am looking for a way to more closely couple the Tbolt circuit board to the 
back plate and am looking for the material switchers use between semiconductor 
and cooling plate Any one know where I can buy it in sheet form?
Bert Kehren




-Original Message-
From: Chris Albertson albertson.ch...@gmail.com
To: Discussion of precise time and frequency measurement time-nuts@febo.com
Sent: Sun, Aug 26, 2012 12:31 pm
Subject: Re: [time-nuts] newbie question Thunderbolt supply


On Sun, Aug 26, 2012 at 3:46 AM, ewkeh...@aol.com wrote:
 Having played with several solutions I found the best is a 12 V 1 A
 switcher with the output voltage increased to 15 V, check the capacitors
 and if
 necessary replace with 25 V. I laid out a PC board that has a TC7662A
 inverter  followed by a 79L12.  Also on the board is a 7812 followed by a
 7805.
 Putting them in series gives me good thermal distribution. 

ne of the advantages of generating waste heat like that is that you can
ut the heat to good use.  I build a temperature controlled fan.  It is
ery simple a temperature sensor IC connects to an opamp that drives a
ower transistor that drives a 12V fan.
As for the power supply.  I used a filter that does not drop any volts and
 can't see any RF on the DC using my old 365 Tek scope or by using a more
ensitive RF power meter.

hris Albertson
edondo Beach, California
__
ime-nuts mailing list -- time-nuts@febo.com
o unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
nd follow the instructions there.

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and follow the instructions there.

Re: [time-nuts] newbie question Thunderbolt supply

[Azelio Boriani]

Here in Europe Farnell has the 3M thermal pad in sheets (105x150mm)...

On Mon, Aug 27, 2012 at 12:48 PM, ew ewkeh...@aol.com wrote:


 Chris
 Starting with 3.4 W used by the Tbolt my battery version burns 4.4 W.
  Using a switcher do generate 7 V   4.8 W and running the 7805 directly
 from 14.5 V 6.2.W. I use like you an IC temp sensor, two stage op amp
 driving a fan holding the backplate temp constant and total power goes up
 to 7.6 W since the oven has to work harder. T bolt, switchers and all
 regulators are on the other side of the 3/32 Alu plate. The AC switcher is
 not included in the power numbers. but is also on the plate. Plate is held
 at 40 C.
 I am looking for a way to more closely couple the Tbolt circuit board to
 the back plate and am looking for the material switchers use between
 semiconductor and cooling plate Any one know where I can buy it in sheet
 form?
 Bert Kehren




 -Original Message-
 From: Chris Albertson albertson.ch...@gmail.com
 To: Discussion of precise time and frequency measurement 
 time-nuts@febo.com
 Sent: Sun, Aug 26, 2012 12:31 pm
 Subject: Re: [time-nuts] newbie question Thunderbolt supply


 On Sun, Aug 26, 2012 at 3:46 AM, ewkeh...@aol.com wrote:
  Having played with several solutions I found the best is a 12 V 1 A
  switcher with the output voltage increased to 15 V, check the capacitors
  and if
  necessary replace with 25 V. I laid out a PC board that has a TC7662A
  inverter  followed by a 79L12.  Also on the board is a 7812 followed by a
  7805.
  Putting them in series gives me good thermal distribution. 

 ne of the advantages of generating waste heat like that is that you can
 ut the heat to good use.  I build a temperature controlled fan.  It is
 ery simple a temperature sensor IC connects to an opamp that drives a
 ower transistor that drives a 12V fan.
 As for the power supply.  I used a filter that does not drop any volts and
  can't see any RF on the DC using my old 365 Tek scope or by using a more
 ensitive RF power meter.

 hris Albertson
 edondo Beach, California
 __
 ime-nuts mailing list -- time-nuts@febo.com
 o unsubscribe, go to
 https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
 nd follow the instructions there.

 ___
 time-nuts mailing list -- time-nuts@febo.com
 To unsubscribe, go to
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Re: [time-nuts] newbie question Thunderbolt supply

[EWKehren]

Thank you. Will look for it here under thermal pad.
Bert
 
 
In a message dated 8/27/2012 8:08:30 A.M. Eastern Daylight Time,  
azelio.bori...@screen.it writes:

Here in  Europe Farnell has the 3M thermal pad in sheets (105x150mm)...

On Mon,  Aug 27, 2012 at 12:48 PM, ew ewkeh...@aol.com  wrote:


 Chris
 Starting with 3.4 W used by the Tbolt  my battery version burns 4.4 W.
  Using a switcher do generate 7  V   4.8 W and running the 7805 directly
 from 14.5 V 6.2.W. I  use like you an IC temp sensor, two stage op amp
 driving a fan holding  the backplate temp constant and total power goes up
 to 7.6 W since the  oven has to work harder. T bolt, switchers and all
 regulators are on  the other side of the 3/32 Alu plate. The AC switcher 
is
 not included  in the power numbers. but is also on the plate. Plate is 
held
 at 40  C.
 I am looking for a way to more closely couple the Tbolt circuit  board to
 the back plate and am looking for the material switchers use  between
 semiconductor and cooling plate Any one know where I can buy  it in sheet
 form?
 Bert  Kehren




 -Original  Message-
 From: Chris Albertson  albertson.ch...@gmail.com
 To: Discussion of precise time and  frequency measurement 
 time-nuts@febo.com
 Sent: Sun,  Aug 26, 2012 12:31 pm
 Subject: Re: [time-nuts] newbie question  Thunderbolt supply


 On Sun, Aug 26, 2012 at 3:46 AM,  ewkeh...@aol.com wrote:
  Having played with several  solutions I found the best is a 12 V 1 A
  switcher with the  output voltage increased to 15 V, check the capacitors
  and  if
  necessary replace with 25 V. I laid out a PC board that has a  TC7662A
  inverter  followed by a 79L12.  Also on the  board is a 7812 followed by 
a
  7805.
  Putting them  in series gives me good thermal distribution. 

 ne of the  advantages of generating waste heat like that is that you can
 ut the  heat to good use.  I build a temperature controlled fan.  It  is
 ery simple a temperature sensor IC connects to an opamp that drives  a
 ower transistor that drives a 12V fan.
 As for the power  supply.  I used a filter that does not drop any volts 
and
   can't see any RF on the DC using my old 365 Tek scope or by using a  
more
 ensitive RF power meter.

 hris Albertson
  edondo Beach, California
  __
 ime-nuts mailing list  -- time-nuts@febo.com
 o unsubscribe, go to
  https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
 nd follow the  instructions there.

  ___
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 To unsubscribe, go to
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 and follow the  instructions  there.

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Re: [time-nuts] newbie question Thunderbolt supply

[Jerry]

Are these thermal pads temp conductive or insulative?  If you want heat
dissipation why not use the readily available thermal grease used for
semiconductor mounting? Cheap and not really messy if applied correctly

jerry

-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of ewkeh...@aol.com
Sent: Monday, August 27, 2012 9:38 AM
To: time-nuts@febo.com
Subject: Re: [time-nuts] newbie question Thunderbolt supply

Thank you. Will look for it here under thermal pad.
Bert
 
 
In a message dated 8/27/2012 8:08:30 A.M. Eastern Daylight Time,
azelio.bori...@screen.it writes:

Here in  Europe Farnell has the 3M thermal pad in sheets (105x150mm)...

On Mon,  Aug 27, 2012 at 12:48 PM, ew ewkeh...@aol.com  wrote:


 Chris
 Starting with 3.4 W used by the Tbolt  my battery version burns 4.4 W.
  Using a switcher do generate 7  V   4.8 W and running the 7805 directly
 from 14.5 V 6.2.W. I  use like you an IC temp sensor, two stage op amp 
 driving a fan holding  the backplate temp constant and total power 
 goes up to 7.6 W since the  oven has to work harder. T bolt, switchers 
 and all regulators are on  the other side of the 3/32 Alu plate. The 
 AC switcher
is
 not included  in the power numbers. but is also on the plate. Plate is
held
 at 40  C.
 I am looking for a way to more closely couple the Tbolt circuit  board 
 to the back plate and am looking for the material switchers use  
 between semiconductor and cooling plate Any one know where I can buy  
 it in sheet form?
 Bert  Kehren




 -Original  Message-
 From: Chris Albertson  albertson.ch...@gmail.com
 To: Discussion of precise time and  frequency measurement  
 time-nuts@febo.com
 Sent: Sun,  Aug 26, 2012 12:31 pm
 Subject: Re: [time-nuts] newbie question  Thunderbolt supply


 On Sun, Aug 26, 2012 at 3:46 AM,  ewkeh...@aol.com wrote:
  Having played with several  solutions I found the best is a 12 V 1 A
  switcher with the  output voltage increased to 15 V, check the 
 capacitors  and  if  necessary replace with 25 V. I laid out a PC 
 board that has a  TC7662A  inverter  followed by a 79L12.  Also on the  
 board is a 7812 followed by
a
  7805.
  Putting them  in series gives me good thermal distribution. 

 ne of the  advantages of generating waste heat like that is that you 
 can ut the  heat to good use.  I build a temperature controlled fan.  
 It  is ery simple a temperature sensor IC connects to an opamp that 
 drives  a ower transistor that drives a 12V fan.
 As for the power  supply.  I used a filter that does not drop any 
 volts
and
   can't see any RF on the DC using my old 365 Tek scope or by using a
more
 ensitive RF power meter.

 hris Albertson
  edondo Beach, California
  __
 ime-nuts mailing list  -- time-nuts@febo.com o unsubscribe, go to  
 https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
 nd follow the  instructions there.

  ___
 time-nuts mailing list  -- time-nuts@febo.com To unsubscribe, go to  
 https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
 and follow the  instructions  there.

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Re: [time-nuts] newbie question Thunderbolt supply

[Michael Tharp]

On 08/27/2012 10:09 AM, Jerry wrote:

Are these thermal pads temp conductive or insulative?  If you want heat
dissipation why not use the readily available thermal grease used for
semiconductor mounting? Cheap and not really messy if applied correctly


A layer of Kapton (polyimide) tape would be electrically insulating but 
still conduct heat well enough for this application. You could then put 
a thermal pad under that and not have to worry about it being conductive 
or (I think) capacitative. I'd prefer the pad to the grease because the 
bottom of a PCB has lots of pointy bits that would keep the plane of the 
PCB spaced away from the plate, and thermal grease is not very effective 
as a filler material. It would also be springy enough to maintain 
contact with the bottom of the PCB.


I'm still not entirely sure this is a good idea though, seems like a 
low-temp oven for the whole tbolt would be better if you want thermal 
stability.


-- m. tharp

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Re: [time-nuts] newbie question Thunderbolt supply

[EWKehren]

There are components and traces.
Bert
 
 
In a message dated 8/27/2012 10:10:45 A.M. Eastern Daylight Time,  
jster...@att.net writes:

Are  these thermal pads temp conductive or insulative?  If you want  heat
dissipation why not use the readily available thermal grease used  for
semiconductor mounting? Cheap and not really messy if applied  correctly

jerry

-Original Message-
From:  time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of  ewkeh...@aol.com
Sent: Monday, August 27, 2012 9:38 AM
To:  time-nuts@febo.com
Subject: Re: [time-nuts] newbie question Thunderbolt  supply

Thank you. Will look for it here under thermal  pad.
Bert


In a message dated 8/27/2012 8:08:30 A.M. Eastern  Daylight Time,
azelio.bori...@screen.it writes:

Here in  Europe  Farnell has the 3M thermal pad in sheets (105x150mm)...

On Mon,   Aug 27, 2012 at 12:48 PM, ew ewkeh...@aol.com   wrote:


 Chris
 Starting with 3.4 W used by the  Tbolt  my battery version burns 4.4 W.
  Using a switcher do  generate 7  V   4.8 W and running the 7805 directly
  from 14.5 V 6.2.W. I  use like you an IC temp sensor, two stage op amp  
 driving a fan holding  the backplate temp constant and total  power 
 goes up to 7.6 W since the  oven has to work harder. T  bolt, switchers 
 and all regulators are on  the other side of the  3/32 Alu plate. The 
 AC switcher
is
 not included  in  the power numbers. but is also on the plate. Plate is
held
 at  40  C.
 I am looking for a way to more closely couple the Tbolt  circuit  board 
 to the back plate and am looking for the material  switchers use  
 between semiconductor and cooling plate Any one  know where I can buy  
 it in sheet form?
 Bert   Kehren




 -Original   Message-
 From: Chris Albertson   albertson.ch...@gmail.com
 To: Discussion of precise time  and  frequency measurement  
 time-nuts@febo.com
  Sent: Sun,  Aug 26, 2012 12:31 pm
 Subject: Re: [time-nuts] newbie  question  Thunderbolt supply


 On Sun, Aug 26, 2012  at 3:46 AM,  ewkeh...@aol.com wrote:
  Having played  with several  solutions I found the best is a 12 V 1 A
   switcher with the  output voltage increased to 15 V, check the 
  capacitors  and  if  necessary replace with 25 V. I laid out a  PC 
 board that has a  TC7662A  inverter  followed by a  79L12.  Also on the  
 board is a 7812 followed  by
a
  7805.
  Putting them  in series gives  me good thermal distribution. 

 ne of the  advantages  of generating waste heat like that is that you 
 can ut the  heat  to good use.  I build a temperature controlled fan.  
  It  is ery simple a temperature sensor IC connects to an opamp that  
 drives  a ower transistor that drives a 12V fan.
 As for  the power  supply.  I used a filter that does not drop any 
  volts
and
   can't see any RF on the DC using my old 365  Tek scope or by using a
more
 ensitive RF power  meter.

 hris Albertson
  edondo Beach,  California
   __
 ime-nuts mailing  list  -- time-nuts@febo.com o unsubscribe, go to  
  https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
 nd follow  the  instructions there.

   ___
 time-nuts mailing  list  -- time-nuts@febo.com To unsubscribe, go to  
  https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
 and follow  the  instructions   there.

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and follow  the  instructions  there.

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and follow  the instructions  there.


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Re: [time-nuts] newbie question Thunderbolt supply

[Jerry]

Sorry I thought the discussion was about the bottom case of the TBolt, not
the PCB,  being in contact with a larger thermal mass. 

jerry

-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of ewkeh...@aol.com
Sent: Monday, August 27, 2012 10:44 AM
To: time-nuts@febo.com
Subject: Re: [time-nuts] newbie question Thunderbolt supply

There are components and traces.
Bert
 
 
In a message dated 8/27/2012 10:10:45 A.M. Eastern Daylight Time,
jster...@att.net writes:

Are  these thermal pads temp conductive or insulative?  If you want  heat
dissipation why not use the readily available thermal grease used  for
semiconductor mounting? Cheap and not really messy if applied  correctly

jerry

-Original Message-
From:  time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of  ewkeh...@aol.com
Sent: Monday, August 27, 2012 9:38 AM
To:  time-nuts@febo.com
Subject: Re: [time-nuts] newbie question Thunderbolt  supply

Thank you. Will look for it here under thermal  pad.
Bert


In a message dated 8/27/2012 8:08:30 A.M. Eastern  Daylight Time,
azelio.bori...@screen.it writes:

Here in  Europe  Farnell has the 3M thermal pad in sheets (105x150mm)...

On Mon,   Aug 27, 2012 at 12:48 PM, ew ewkeh...@aol.com   wrote:


 Chris
 Starting with 3.4 W used by the  Tbolt  my battery version burns 4.4 W.
  Using a switcher do  generate 7  V   4.8 W and running the 7805 directly
  from 14.5 V 6.2.W. I  use like you an IC temp sensor, two stage op 
 amp driving a fan holding  the backplate temp constant and total  
 power goes up to 7.6 W since the  oven has to work harder. T  bolt, 
 switchers and all regulators are on  the other side of the  3/32 Alu 
 plate. The AC switcher
is
 not included  in  the power numbers. but is also on the plate. Plate 
 is
held
 at  40  C.
 I am looking for a way to more closely couple the Tbolt  circuit  
 board to the back plate and am looking for the material  switchers use 
 between semiconductor and cooling plate Any one  know where I can buy 
 it in sheet form?
 Bert   Kehren




 -Original   Message-
 From: Chris Albertson   albertson.ch...@gmail.com
 To: Discussion of precise time  and  frequency measurement  
 time-nuts@febo.com
  Sent: Sun,  Aug 26, 2012 12:31 pm
 Subject: Re: [time-nuts] newbie  question  Thunderbolt supply


 On Sun, Aug 26, 2012  at 3:46 AM,  ewkeh...@aol.com wrote:
  Having played  with several  solutions I found the best is a 12 V 1 A
   switcher with the  output voltage increased to 15 V, check the 
  capacitors  and  if  necessary replace with 25 V. I laid out a  PC 
 board that has a  TC7662A  inverter  followed by a  79L12.  Also on the  
 board is a 7812 followed  by
a
  7805.
  Putting them  in series gives  me good thermal distribution. 

 ne of the  advantages  of generating waste heat like that is that you 
 can ut the  heat  to good use.  I build a temperature controlled fan.  
  It  is ery simple a temperature sensor IC connects to an opamp that  
 drives  a ower transistor that drives a 12V fan.
 As for  the power  supply.  I used a filter that does not drop any 
  volts
and
   can't see any RF on the DC using my old 365  Tek scope or by using a
more
 ensitive RF power  meter.

 hris Albertson
  edondo Beach,  California
   __
 ime-nuts mailing  list  -- time-nuts@febo.com o unsubscribe, go to  
  https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
 nd follow  the  instructions there.

   ___
 time-nuts mailing  list  -- time-nuts@febo.com To unsubscribe, go to  
  https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
 and follow  the  instructions   there.

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Re: [time-nuts] newbie question Thunderbolt supply

[Chris Albertson]

On Mon, Aug 27, 2012 at 3:48 AM, ew ewkeh...@aol.com wrote:


 te and am looking for the material switchers use between semiconductor and
 cooling plate Any one know where I can buy it in sheet form?
 Bert Kehren


What happens if you flood the entire assembly in transformer oil?  Aside
from making a mess.

Or look here: 
Thermal-Thermal_Pads_Tapehttp://www.frozencpu.com/cat/l2/g8/c487/list/p1/Thermal-Thermal_Pads_Tape.html

-- 

Chris Albertson
Redondo Beach, California
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Re: [time-nuts] newbie question Thunderbolt supply

[Bob Camp]

Hi

It's probably easier to put the TBolt inside a sealed box along with a small
/low speed / quiet fan. Let the moving air equalize everything. If vibration
is a concern, mount the fan on some sort of isolators. 

Bob

-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of Chris Albertson
Sent: Monday, August 27, 2012 12:02 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] newbie question Thunderbolt supply

On Mon, Aug 27, 2012 at 3:48 AM, ew ewkeh...@aol.com wrote:


 te and am looking for the material switchers use between semiconductor and
 cooling plate Any one know where I can buy it in sheet form?
 Bert Kehren


What happens if you flood the entire assembly in transformer oil?  Aside
from making a mess.

Or look here:
Thermal-Thermal_Pads_Tapehttp://www.frozencpu.com/cat/l2/g8/c487/list/p1/Th
ermal-Thermal_Pads_Tape.html

-- 

Chris Albertson
Redondo Beach, California
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and follow the instructions there.

Re: [time-nuts] newbie question Thunderbolt supply

[Ed Palmer]

There are thermal pads that are thermally conductive.  You typically see 
them in laptops and, oddly, optical drives.  They're usually one or two 
mm thick and very soft and squishy.  Pull the bottom plate off any 
full-size optical drive and you'll probably find one or two pieces.  I 
see lots of them on the auction site, but I have no personal experience 
with those.  It looks like there's at least one or two that are 
available in large pieces and I saw thicknesses from 0.4mm up to 4.0mm.


I wouldn't expect these to move heat nearly as well as a thin layer of 
thermal grease (which is itself a thermal insulator), but for some 
applications it works and is the only practical solution.


Ed

On 8/27/2012 10:12 AM, Bob Camp wrote:

Hi

The pad stuff is normally an insulator. It's not very stable, so there may
be better alternatives.

Bob

-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of ewkeh...@aol.com
Sent: Monday, August 27, 2012 10:44 AM
To: time-nuts@febo.com
Subject: Re: [time-nuts] newbie question Thunderbolt supply

There are components and traces.
Bert
  
  
In a message dated 8/27/2012 10:10:45 A.M. Eastern Daylight Time,

jster...@att.net writes:

Are  these thermal pads temp conductive or insulative?  If you want  heat
dissipation why not use the readily available thermal grease used  for
semiconductor mounting? Cheap and not really messy if applied  correctly

jerry

-Original Message-
From:  time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of  ewkeh...@aol.com
Sent: Monday, August 27, 2012 9:38 AM
To:  time-nuts@febo.com
Subject: Re: [time-nuts] newbie question Thunderbolt  supply

Thank you. Will look for it here under thermal  pad.
Bert


In a message dated 8/27/2012 8:08:30 A.M. Eastern  Daylight Time,
azelio.bori...@screen.it writes:

Here in  Europe  Farnell has the 3M thermal pad in sheets (105x150mm)...

On Mon,   Aug 27, 2012 at 12:48 PM, ew ewkeh...@aol.com   wrote:


Chris
Starting with 3.4 W used by the  Tbolt  my battery version burns 4.4 W.
  Using a switcher do  generate 7  V   4.8 W and running the 7805 directly
  from 14.5 V 6.2.W. I  use like you an IC temp sensor, two stage op amp
driving a fan holding  the backplate temp constant and total  power
goes up to 7.6 W since the  oven has to work harder. T  bolt, switchers
and all regulators are on  the other side of the  3/32 Alu plate. The
AC switcher

is

not included  in  the power numbers. but is also on the plate. Plate is

held

at  40  C.
I am looking for a way to more closely couple the Tbolt  circuit  board
to the back plate and am looking for the material  switchers use
between semiconductor and cooling plate Any one  know where I can buy
it in sheet form?
Bert   Kehren




-Original   Message-
From: Chris Albertson   albertson.ch...@gmail.com
To: Discussion of precise time  and  frequency measurement 
time-nuts@febo.com
  Sent: Sun,  Aug 26, 2012 12:31 pm
Subject: Re: [time-nuts] newbie  question  Thunderbolt supply


On Sun, Aug 26, 2012  at 3:46 AM,  ewkeh...@aol.com wrote:

Having played  with several  solutions I found the best is a 12 V 1 A

   switcher with the  output voltage increased to 15 V, check the
  capacitors  and  if  necessary replace with 25 V. I laid out a  PC
board that has a  TC7662A  inverter  followed by a  79L12.  Also on the
board is a 7812 followed  by

a

  7805.
  Putting them  in series gives  me good thermal distribution. 

ne of the  advantages  of generating waste heat like that is that you
can ut the  heat  to good use.  I build a temperature controlled fan.
  It  is ery simple a temperature sensor IC connects to an opamp that
drives  a ower transistor that drives a 12V fan.
As for  the power  supply.  I used a filter that does not drop any
  volts

and

   can't see any RF on the DC using my old 365  Tek scope or by using a

more

ensitive RF power  meter.

hris Albertson
  edondo Beach,  California
   __
ime-nuts mailing  list  -- time-nuts@febo.com o unsubscribe, go to
  https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
nd follow  the  instructions there.

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Re: [time-nuts] newbie question Thunderbolt supply

[J. L. Trantham]

The thermal pads are, generally, electrically 'insulative' but heat
'conductive'.  However, the screws that are usually used to mount the TBolt
are metal and conduct electricity.  Therefore, the main focus should be to
transfer heat for the purpose of keeping the TBolt at a constant
temperature.  The transfer of electricity is secondary.  The screws provide
DC and AC conductivity and the pads augment AC conductivity.

Joe

-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of Jerry
Sent: Monday, August 27, 2012 9:09 AM
To: 'Discussion of precise time and frequency measurement'
Subject: Re: [time-nuts] newbie question Thunderbolt supply


Are these thermal pads temp conductive or insulative?  If you want heat
dissipation why not use the readily available thermal grease used for
semiconductor mounting? Cheap and not really messy if applied correctly

jerry

-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of ewkeh...@aol.com
Sent: Monday, August 27, 2012 9:38 AM
To: time-nuts@febo.com
Subject: Re: [time-nuts] newbie question Thunderbolt supply

Thank you. Will look for it here under thermal pad.
Bert
 
 
In a message dated 8/27/2012 8:08:30 A.M. Eastern Daylight Time,
azelio.bori...@screen.it writes:

Here in  Europe Farnell has the 3M thermal pad in sheets (105x150mm)...

On Mon,  Aug 27, 2012 at 12:48 PM, ew ewkeh...@aol.com  wrote:


 Chris
 Starting with 3.4 W used by the Tbolt  my battery version burns 4.4 W.
  Using a switcher do generate 7  V   4.8 W and running the 7805 directly
 from 14.5 V 6.2.W. I  use like you an IC temp sensor, two stage op amp
 driving a fan holding  the backplate temp constant and total power 
 goes up to 7.6 W since the  oven has to work harder. T bolt, switchers 
 and all regulators are on  the other side of the 3/32 Alu plate. The 
 AC switcher
is
 not included  in the power numbers. but is also on the plate. Plate is
held
 at 40  C.
 I am looking for a way to more closely couple the Tbolt circuit  board
 to the back plate and am looking for the material switchers use  
 between semiconductor and cooling plate Any one know where I can buy  
 it in sheet form?
 Bert  Kehren




 -Original  Message-
 From: Chris Albertson  albertson.ch...@gmail.com
 To: Discussion of precise time and  frequency measurement 
 time-nuts@febo.com
 Sent: Sun,  Aug 26, 2012 12:31 pm
 Subject: Re: [time-nuts] newbie question  Thunderbolt supply


 On Sun, Aug 26, 2012 at 3:46 AM,  ewkeh...@aol.com wrote:
  Having played with several  solutions I found the best is a 12 V 1 A
  switcher with the  output voltage increased to 15 V, check the
 capacitors  and  if  necessary replace with 25 V. I laid out a PC 
 board that has a  TC7662A  inverter  followed by a 79L12.  Also on the  
 board is a 7812 followed by
a
  7805.
  Putting them  in series gives me good thermal distribution. 

 ne of the  advantages of generating waste heat like that is that you
 can ut the  heat to good use.  I build a temperature controlled fan.  
 It  is ery simple a temperature sensor IC connects to an opamp that 
 drives  a ower transistor that drives a 12V fan.
 As for the power  supply.  I used a filter that does not drop any 
 volts
and
   can't see any RF on the DC using my old 365 Tek scope or by using a
more
 ensitive RF power meter.

 hris Albertson
  edondo Beach, California  
 __
 ime-nuts mailing list  -- time-nuts@febo.com o unsubscribe, go to
 https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
 nd follow the  instructions there.

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Re: [time-nuts] newbie question Thunderbolt supply

[EWKehren]

Having played with several solutions I found the best is a 12 V 1 A  
switcher with the output voltage increased to 15 V, check the capacitors and if 
 
necessary replace with 25 V. I laid out a PC board that has a TC7662A 
inverter  followed by a 79L12.  Also on the board is a 7812 followed by a 7805. 
 
Putting them in series gives me good thermal distribution. In my opinion every 
 thing else is an overkill. 
Working with very low noise PLL's I have found that getting rid of switcher 
 noise is much easier than 60 Hz.
There are other pin compatible alternatives to the TC7662A, even a 555 will 
 work, just more components.
Bert Kehren 
 
 
In a message dated 8/25/2012 8:10:07 P.M. Eastern Daylight Time,  
li...@rtty.us writes:

Hi

The easy way to do a TBolt supply is to start with  something between 15 
and 18 volts.  Regulate down to 12 and 5 with linear  regulators. 7805's are 
fine for the +5. Something like a LT1764 might be  better for the +12. The 
-12 supply is very low current and does not matter  much. People have had good 
luck with voltage inversion chips off the +15 and  then something like a 
79L12.

Bob

On Aug 25, 2012, at 6:41 PM,  Edgardo Molina xe1...@amsat.org wrote:

 Dear Chris,
  
 Good afternoon. I am in the process of mounting my TBolt to a 2U 19  
rack enclosure and was looking for a decent power supply. I found the Cisco  
unit and I am ordering a couple of them just in case. It would really be nice  
if I could have access to the diagram of the upgrade you did on yours to  
recreate the same performance from the Cisco unit. Please do not feel  
compromised if it is difficult to share. I didn't mean to be rude and if my  
note 
causes you any discomfort please kindly disregard it. I jumped into the  
thread because of experiencing the same doubts as the originator of it.  
 
 Redondo Beach? I love visiting there whenever visiting my  brother who 
lives in Rancho Palos Verdes. I would invite you lunch anytime  just for the 
pleasure of meeting you in person.
 
 Thank  you.
 
 Regards,
 
 
 
 
  
 Edgardo Molina
 Dirección IPTEL
 
  www.iptel.net.mx
 
 T : 55 55 55202444
 M : 04455  20501854
 
 Piensa en Bits SA de CV
 
 
  
 Información anexa:
 
 
 
 
  CONFIDENCIALIDAD DE INFORMACION
 
 Este mensaje tiene carácter  confidencial. Si usted no es el destinarario 
de este mensaje, le suplicamos se  lo notifique al remitente mediante un 
correo electrónico y que borre el  presente mensaje y sus anexos de su 
computadora sin retener una copia de los  mismos. Queda estrictamente prohibido 
copiar este mensaje o hacer usode el  para cualquier propósito o divulgar su en 
forma parcial o total su contenido.  Gracias.
 
 
 NON-DISCLOSURE OF INFORMATION
  
 This email is strictly confidential and may also be privileged. If  you 
are not the intended recipient please immediately advise the sender by  
replying to this e-mail and then deleting the message and its attachments from  
your computer without keeping a copy. It is strictly forbidden to copy it or  
use it for any purpose or disclose its contents to any third party. Thank  
you.
 
 
 
 
 
 On Aug 25, 2012, at  3:26 PM, Chris Albertson albertson.ch...@gmail.com 
wrote:
  
 On Sat, Aug 25, 2012 at 1:06 PM, Jerry jster...@att.net  wrote:
 
 I am using a Cisco supply 3 voltage supply  for the T-bolt.  Is there 
any
 performance loss if the  +12vdc rail and the -12vdc rail are off by a 
few %
 in opposite  directions, e,g  +11.7 vdc and -12.3vdc ?
  
 The true nuts here on the time nuts list will tell you that  the noise 
from
 a switching power supply is bad and that you need a  regulated linear 
power
 supply.   But for most practical  purposes the Cisco supply is a good 
one.
 Being only slightly nuts  myself.  I use the Cisco   supply but I built a
  small power adaptor board with matching connectors and some pi  
filters
 made with RF choke and capacitors.  I realy don't  thing the filters are
 needed but I wanted a connectorized  installation and a small choke was 
as
 easy to solder in as a  length of wire.
 
 -- 
 
 Chris  Albertson
 Redondo Beach, California
  ___
 time-nuts mailing  list -- time-nuts@febo.com
 To unsubscribe, go to  
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 and follow  the instructions there.
 
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 To unsubscribe, go to  
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Re: [time-nuts] newbie question Thunderbolt supply

[Bob Camp]

Hi

The only real disadvantage of a 7812 / 340-12 is it's relatively high drop out 
voltage compared to a 1764 (or similar). Stability of any of them will be 
impacted more by thermal issues than anything else. The colder you can keep the 
12V regulator, the more stable it will be. The +12 is by far the most sensitive 
supply line on the TBolt.

Bob

On Aug 26, 2012, at 6:46 AM, ewkeh...@aol.com wrote:

 Having played with several solutions I found the best is a 12 V 1 A  
 switcher with the output voltage increased to 15 V, check the capacitors and 
 if  
 necessary replace with 25 V. I laid out a PC board that has a TC7662A 
 inverter  followed by a 79L12.  Also on the board is a 7812 followed by a 
 7805.  
 Putting them in series gives me good thermal distribution. In my opinion 
 every 
 thing else is an overkill. 
 Working with very low noise PLL's I have found that getting rid of switcher 
 noise is much easier than 60 Hz.
 There are other pin compatible alternatives to the TC7662A, even a 555 will 
 work, just more components.
 Bert Kehren 
 
 
 In a message dated 8/25/2012 8:10:07 P.M. Eastern Daylight Time,  
 li...@rtty.us writes:
 
 Hi
 
 The easy way to do a TBolt supply is to start with  something between 15 
 and 18 volts.  Regulate down to 12 and 5 with linear  regulators. 7805's are 
 fine for the +5. Something like a LT1764 might be  better for the +12. The 
 -12 supply is very low current and does not matter  much. People have had 
 good 
 luck with voltage inversion chips off the +15 and  then something like a 
 79L12.
 
 Bob
 
 On Aug 25, 2012, at 6:41 PM,  Edgardo Molina xe1...@amsat.org wrote:
 
 Dear Chris,
 
 Good afternoon. I am in the process of mounting my TBolt to a 2U 19  
 rack enclosure and was looking for a decent power supply. I found the Cisco  
 unit and I am ordering a couple of them just in case. It would really be nice 
  
 if I could have access to the diagram of the upgrade you did on yours to  
 recreate the same performance from the Cisco unit. Please do not feel  
 compromised if it is difficult to share. I didn't mean to be rude and if my  
 note 
 causes you any discomfort please kindly disregard it. I jumped into the  
 thread because of experiencing the same doubts as the originator of it.  
 
 Redondo Beach? I love visiting there whenever visiting my  brother who 
 lives in Rancho Palos Verdes. I would invite you lunch anytime  just for the 
 pleasure of meeting you in person.
 
 Thank  you.
 
 Regards,
 
 
 
 
 
 Edgardo Molina
 Dirección IPTEL
 
 www.iptel.net.mx
 
 T : 55 55 55202444
 M : 04455  20501854
 
 Piensa en Bits SA de CV
 
 
 
 Información anexa:
 
 
 
 
 CONFIDENCIALIDAD DE INFORMACION
 
 Este mensaje tiene carácter  confidencial. Si usted no es el destinarario 
 de este mensaje, le suplicamos se  lo notifique al remitente mediante un 
 correo electrónico y que borre el  presente mensaje y sus anexos de su 
 computadora sin retener una copia de los  mismos. Queda estrictamente 
 prohibido 
 copiar este mensaje o hacer usode el  para cualquier propósito o divulgar su 
 en 
 forma parcial o total su contenido.  Gracias.
 
 
 NON-DISCLOSURE OF INFORMATION
 
 This email is strictly confidential and may also be privileged. If  you 
 are not the intended recipient please immediately advise the sender by  
 replying to this e-mail and then deleting the message and its attachments 
 from  
 your computer without keeping a copy. It is strictly forbidden to copy it or  
 use it for any purpose or disclose its contents to any third party. Thank  
 you.
 
 
 
 
 
 On Aug 25, 2012, at  3:26 PM, Chris Albertson albertson.ch...@gmail.com 
 wrote:
 
 On Sat, Aug 25, 2012 at 1:06 PM, Jerry jster...@att.net  wrote:
 
 I am using a Cisco supply 3 voltage supply  for the T-bolt.  Is there 
 any
 performance loss if the  +12vdc rail and the -12vdc rail are off by a 
 few %
 in opposite  directions, e,g  +11.7 vdc and -12.3vdc ?
 
 The true nuts here on the time nuts list will tell you that  the noise 
 from
 a switching power supply is bad and that you need a  regulated linear 
 power
 supply.   But for most practical  purposes the Cisco supply is a good 
 one.
 Being only slightly nuts  myself.  I use the Cisco   supply but I built a
 small power adaptor board with matching connectors and some pi  
 filters
 made with RF choke and capacitors.  I realy don't  thing the filters are
 needed but I wanted a connectorized  installation and a small choke was 
 as
 easy to solder in as a  length of wire.
 
 -- 
 
 Chris  Albertson
 Redondo Beach, California
 ___
 time-nuts mailing  list -- time-nuts@febo.com
 To unsubscribe, go to  
 https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
 and follow  the instructions there.
 
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 To unsubscribe, go to  
 https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
 and follow the  

Re: [time-nuts] newbie question Thunderbolt supply

[Magnus Danielson]

On 08/26/2012 02:07 PM, Bob Camp wrote:

Hi

The only real disadvantage of a 7812 / 340-12 is it's relatively high drop out 
voltage compared to a 1764 (or similar). Stability of any of them will be 
impacted more by thermal issues than anything else. The colder you can keep the 
12V regulator, the more stable it will be. The +12 is by far the most sensitive 
supply line on the TBolt.


Switcher to give a fairly stable voltage, filtered for noise and then 
linear stepdown for the last step. It's been done in high power audio 
amplifiers the last 20 years or so.


Cheers,
Magnus

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and follow the instructions there.

Re: [time-nuts] newbie question Thunderbolt supply

[EWKehren]

Having played with most combinations I could think of including the 1764  
there is a lot to be said about the stability of the 7812 and mounting every  
thing on one plate since power dissipation of the OCXO decreases with 
increase  in ambient temperature and current fluctuation is minimal since input 
from the  switcher is very stable and 78 tabs are bolted to the aluminum 
plate. I am  staying with 5 V regulator fed by 7812. 
Using battery backup changes every thing and I use a switcher for the 5V  
followed by a LDO and a separate switcher for the 12 V again followed by a  
LDO.
Bert Kehren
 
 
In a message dated 8/26/2012 8:09:03 A.M. Eastern Daylight Time,  
li...@rtty.us writes:

Hi

The only real disadvantage of a 7812 / 340-12 is it's  relatively high drop 
out voltage compared to a 1764 (or similar). Stability of  any of them will 
be impacted more by thermal issues than anything else. The  colder you can 
keep the 12V regulator, the more stable it will be. The +12 is  by far the 
most sensitive supply line on the TBolt.

Bob

On Aug  26, 2012, at 6:46 AM, ewkeh...@aol.com wrote:

 Having played with  several solutions I found the best is a 12 V 1 A  
 switcher with  the output voltage increased to 15 V, check the capacitors 
and if   
 necessary replace with 25 V. I laid out a PC board that has a TC7662A  
 inverter  followed by a 79L12.  Also on the board is a 7812  followed by 
a 7805.  
 Putting them in series gives me good  thermal distribution. In my opinion 
every 
 thing else is an overkill.  
 Working with very low noise PLL's I have found that getting rid of  
switcher 
 noise is much easier than 60 Hz.
 There are other pin  compatible alternatives to the TC7662A, even a 555 
will 
 work, just  more components.
 Bert Kehren 
 
 
 In a message  dated 8/25/2012 8:10:07 P.M. Eastern Daylight Time,  
  li...@rtty.us writes:
 
 Hi
 
 The easy way to do  a TBolt supply is to start with  something between 15 
 and 18  volts.  Regulate down to 12 and 5 with linear  regulators. 7805's 
 are 
 fine for the +5. Something like a LT1764 might be  better  for the +12. 
The 
 -12 supply is very low current and does not  matter  much. People have 
had good 
 luck with voltage inversion  chips off the +15 and  then something like a 
 79L12.
  
 Bob
 
 On Aug 25, 2012, at 6:41 PM,  Edgardo  Molina xe1...@amsat.org wrote:
 
 Dear  Chris,
 
 Good afternoon. I am in the process of  mounting my TBolt to a 2U 19  
 rack enclosure and was looking  for a decent power supply. I found the 
Cisco 
 unit and I am ordering a  couple of them just in case. It would really be 
nice  
 if I could  have access to the diagram of the upgrade you did on yours to 
 
  recreate the same performance from the Cisco unit. Please do not feel   
 compromised if it is difficult to share. I didn't mean to be rude and  if 
my  note 
 causes you any discomfort please kindly disregard  it. I jumped into the  
 thread because of experiencing the same  doubts as the originator of it.  
 
 Redondo Beach?  I love visiting there whenever visiting my  brother who 
 lives in  Rancho Palos Verdes. I would invite you lunch anytime  just for 
the  
 pleasure of meeting you in person.
 
  Thank  you.
 
 Regards,
 
  
 
 
 
 Edgardo Molina
  Dirección IPTEL
 
 www.iptel.net.mx
  
 T : 55 55 55202444
 M : 04455   20501854
 
 Piensa en Bits SA de CV
  
 
 
 Información anexa:
  
 
 
 
 CONFIDENCIALIDAD DE  INFORMACION
 
 Este mensaje tiene carácter   confidencial. Si usted no es el 
destinarario 
 de este mensaje, le  suplicamos se  lo notifique al remitente mediante un 
 correo  electrónico y que borre el  presente mensaje y sus anexos de su 
  computadora sin retener una copia de los  mismos. Queda estrictamente  
prohibido 
 copiar este mensaje o hacer usode el  para cualquier  propósito o 
divulgar su en 
 forma parcial o total su contenido.   Gracias.
 
 
 NON-DISCLOSURE OF  INFORMATION
 
 This email is strictly confidential and  may also be privileged. If  you 
 are not the intended recipient  please immediately advise the sender by  
 replying to this e-mail  and then deleting the message and its 
attachments from  
 your  computer without keeping a copy. It is strictly forbidden to copy 
it or   
 use it for any purpose or disclose its contents to any third party.  
Thank  
 you.
 
 
 
  
 
 On Aug 25, 2012, at  3:26 PM, Chris Albertson  
albertson.ch...@gmail.com 
 wrote:
 
  On Sat, Aug 25, 2012 at 1:06 PM, Jerry jster...@att.net   wrote:
 
 I am using a Cisco supply 3  voltage supply  for the T-bolt.  Is there 
  any
 performance loss if the  +12vdc rail and the  -12vdc rail are off by a 
 few %
 in opposite   directions, e,g  +11.7 vdc and -12.3vdc ?
  
 The true nuts here on the time nuts list will tell you  that  the 
noise 
 from
 a switching power supply is  bad and that you need a  regulated linear 
 power
  supply.   But for most practical  purposes the Cisco supply is  a good 
 one.
 Being only slightly nuts   myself.  I use the 

Re: [time-nuts] newbie question Thunderbolt supply

[Chris Albertson]

On Sun, Aug 26, 2012 at 3:46 AM, ewkeh...@aol.com wrote:

 Having played with several solutions I found the best is a 12 V 1 A
 switcher with the output voltage increased to 15 V, check the capacitors
 and if
 necessary replace with 25 V. I laid out a PC board that has a TC7662A
 inverter  followed by a 79L12.  Also on the board is a 7812 followed by a
 7805.
 Putting them in series gives me good thermal distribution. 


One of the advantages of generating waste heat like that is that you can
but the heat to good use.  I build a temperature controlled fan.  It is
very simple a temperature sensor IC connects to an opamp that drives a
power transistor that drives a 12V fan.

As for the power supply.  I used a filter that does not drop any volts and
I can't see any RF on the DC using my old 365 Tek scope or by using a more
sensitive RF power meter.


Chris Albertson
Redondo Beach, California
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Re: [time-nuts] newbie question Thunderbolt supply

[Don Latham]

Hi all: I'm using buck regulators from our ebay friends, e.g. 130704328176
at a little over $1.00 apiece, settable to 5 v or 12 v or whatever,
capable of 3 A with good heatsink. Foldback protection. Better than a
3-legged fuse, as my good gaffer Argus calls 'em.
Don

Bob Camp
 Hi

 The only real disadvantage of a 7812 / 340-12 is it's relatively high
 drop out voltage compared to a 1764 (or similar). Stability of any of
 them will be impacted more by thermal issues than anything else. The
 colder you can keep the 12V regulator, the more stable it will be. The
 +12 is by far the most sensitive supply line on the TBolt.

 Bob

 On Aug 26, 2012, at 6:46 AM, ewkeh...@aol.com wrote:

 Having played with several solutions I found the best is a 12 V 1 A
 switcher with the output voltage increased to 15 V, check the
 capacitors and if
 necessary replace with 25 V. I laid out a PC board that has a TC7662A
 inverter  followed by a 79L12.  Also on the board is a 7812 followed
 by a 7805.
 Putting them in series gives me good thermal distribution. In my
 opinion every
 thing else is an overkill.
 Working with very low noise PLL's I have found that getting rid of
 switcher
 noise is much easier than 60 Hz.
 There are other pin compatible alternatives to the TC7662A, even a 555
 will
 work, just more components.
 Bert Kehren


 In a message dated 8/25/2012 8:10:07 P.M. Eastern Daylight Time,
 li...@rtty.us writes:

 Hi

 The easy way to do a TBolt supply is to start with  something between
 15
 and 18 volts.  Regulate down to 12 and 5 with linear  regulators.
 7805's are
 fine for the +5. Something like a LT1764 might be  better for the +12.
 The
 -12 supply is very low current and does not matter  much. People have
 had good
 luck with voltage inversion chips off the +15 and  then something like
 a
 79L12.

 Bob

 On Aug 25, 2012, at 6:41 PM,  Edgardo Molina xe1...@amsat.org wrote:

 Dear Chris,

 Good afternoon. I am in the process of mounting my TBolt to a 2U 19
 rack enclosure and was looking for a decent power supply. I found the
 Cisco
 unit and I am ordering a couple of them just in case. It would really
 be nice
 if I could have access to the diagram of the upgrade you did on yours
 to
 recreate the same performance from the Cisco unit. Please do not feel
 compromised if it is difficult to share. I didn't mean to be rude and
 if my  note
 causes you any discomfort please kindly disregard it. I jumped into
 the
 thread because of experiencing the same doubts as the originator of
 it.

 Redondo Beach? I love visiting there whenever visiting my  brother
 who
 lives in Rancho Palos Verdes. I would invite you lunch anytime  just
 for the
 pleasure of meeting you in person.

 Thank  you.

 Regards,





 Edgardo Molina
 Dirección IPTEL

 www.iptel.net.mx

 T : 55 55 55202444
 M : 04455  20501854

 Piensa en Bits SA de CV



 Información anexa:




 CONFIDENCIALIDAD DE INFORMACION

 Este mensaje tiene carácter  confidencial. Si usted no es el
 destinarario
 de este mensaje, le suplicamos se  lo notifique al remitente mediante
 un
 correo electrónico y que borre el  presente mensaje y sus anexos de su
 computadora sin retener una copia de los  mismos. Queda estrictamente
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 copiar este mensaje o hacer usode el  para cualquier propósito o
 divulgar su en
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 NON-DISCLOSURE OF INFORMATION

 This email is strictly confidential and may also be privileged. If
 you
 are not the intended recipient please immediately advise the sender by
 replying to this e-mail and then deleting the message and its
 attachments from
 your computer without keeping a copy. It is strictly forbidden to copy
 it or
 use it for any purpose or disclose its contents to any third party.
 Thank
 you.





 On Aug 25, 2012, at  3:26 PM, Chris Albertson
 albertson.ch...@gmail.com
 wrote:

 On Sat, Aug 25, 2012 at 1:06 PM, Jerry jster...@att.net  wrote:

 I am using a Cisco supply 3 voltage supply  for the T-bolt.  Is
 there
 any
 performance loss if the  +12vdc rail and the -12vdc rail are off by
 a
 few %
 in opposite  directions, e,g  +11.7 vdc and -12.3vdc ?

 The true nuts here on the time nuts list will tell you that  the
 noise
 from
 a switching power supply is bad and that you need a  regulated
 linear
 power
 supply.   But for most practical  purposes the Cisco supply is a
 good
 one.
 Being only slightly nuts  myself.  I use the Cisco   supply but I
 built a
 small power adaptor board with matching connectors and some pi
 filters
 made with RF choke and capacitors.  I realy don't  thing the filters
 are
 needed but I wanted a connectorized  installation and a small choke
 was
 as
 easy to solder in as a  length of wire.

 --

 Chris  Albertson
 Redondo Beach, California
 ___
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Re: [time-nuts] newbie question Thunderbolt supply

[Bob Camp]

Hi

As long as the +12 is stable a few percent isn't going to hurt anything. The 
-12 can be off by a few volts and everything will be fine.

Bob

On Aug 25, 2012, at 4:06 PM, Jerry jster...@att.net wrote:

 I am using a Cisco supply 3 voltage supply for the T-bolt.  Is there any
 performance loss if the +12vdc rail and the -12vdc rail are off by a few %
 in opposite directions, e,g  +11.7 vdc and -12.3vdc ?  
 
 Tia
 Jerry
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Re: [time-nuts] newbie question Thunderbolt supply

[Chris Albertson]

On Sat, Aug 25, 2012 at 1:06 PM, Jerry jster...@att.net wrote:

 I am using a Cisco supply 3 voltage supply for the T-bolt.  Is there any
 performance loss if the +12vdc rail and the -12vdc rail are off by a few %
 in opposite directions, e,g  +11.7 vdc and -12.3vdc ?

 The true nuts here on the time nuts list will tell you that the noise from
a switching power supply is bad and that you need a regulated linear power
supply.   But for most practical purposes the Cisco supply is a good one.
 Being only slightly nuts myself.  I use the Cisco   supply but I built a
small power adaptor board with matching connectors and some pi filters
made with RF choke and capacitors.  I realy don't thing the filters are
needed but I wanted a connectorized installation and a small choke was as
easy to solder in as a length of wire.

-- 

Chris Albertson
Redondo Beach, California
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Re: [time-nuts] newbie question Thunderbolt supply

[Edgardo Molina]

Dear Chris,

Good afternoon. I am in the process of mounting my TBolt to a 2U 19 rack 
enclosure and was looking for a decent power supply. I found the Cisco unit and 
I am ordering a couple of them just in case. It would really be nice if I could 
have access to the diagram of the upgrade you did on yours to recreate the same 
performance from the Cisco unit. Please do not feel compromised if it is 
difficult to share. I didn't mean to be rude and if my note causes you any 
discomfort please kindly disregard it. I jumped into the thread because of 
experiencing the same doubts as the originator of it. 

Redondo Beach? I love visiting there whenever visiting my brother who lives in 
Rancho Palos Verdes. I would invite you lunch anytime just for the pleasure of 
meeting you in person.

Thank you.

Regards,





Edgardo Molina
Dirección IPTEL

www.iptel.net.mx

T : 55 55 55202444
M : 04455 20501854

Piensa en Bits SA de CV



Información anexa:




CONFIDENCIALIDAD DE INFORMACION

Este mensaje tiene carácter confidencial. Si usted no es el destinarario de 
este mensaje, le suplicamos se lo notifique al remitente mediante un correo 
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retener una copia de los mismos. Queda estrictamente prohibido copiar este 
mensaje o hacer usode el para cualquier propósito o divulgar su en forma 
parcial o total su contenido. Gracias.


NON-DISCLOSURE OF INFORMATION

This email is strictly confidential and may also be privileged. If you are not 
the intended recipient please immediately advise the sender by replying to this 
e-mail and then deleting the message and its attachments from your computer 
without keeping a copy. It is strictly forbidden to copy it or use it for any 
purpose or disclose its contents to any third party. Thank you.





On Aug 25, 2012, at 3:26 PM, Chris Albertson albertson.ch...@gmail.com wrote:

 On Sat, Aug 25, 2012 at 1:06 PM, Jerry jster...@att.net wrote:
 
 I am using a Cisco supply 3 voltage supply for the T-bolt.  Is there any
 performance loss if the +12vdc rail and the -12vdc rail are off by a few %
 in opposite directions, e,g  +11.7 vdc and -12.3vdc ?
 
 The true nuts here on the time nuts list will tell you that the noise from
 a switching power supply is bad and that you need a regulated linear power
 supply.   But for most practical purposes the Cisco supply is a good one.
 Being only slightly nuts myself.  I use the Cisco   supply but I built a
 small power adaptor board with matching connectors and some pi filters
 made with RF choke and capacitors.  I realy don't thing the filters are
 needed but I wanted a connectorized installation and a small choke was as
 easy to solder in as a length of wire.
 
 -- 
 
 Chris Albertson
 Redondo Beach, California
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Re: [time-nuts] newbie question Thunderbolt supply

[Chris Albertson]

I never made a diagram.   All I did was solder down a terminal block to
each end of a piece of prototype board.  I connected the power lines using
some small inductors I had and bypassed power to ground using (I think)
0.01 caps.

I mounted the Cisco power supply block to the inside of the case using hot
glue.

As I remember the Cisco PS needs to have one line grounded to make it turn
on.   I figured that out when I got zero volts on the cable.

On Sat, Aug 25, 2012 at 3:41 PM, Edgardo Molina xe1...@amsat.org wrote:

 Dear Chris,

 Good afternoon. I am in the process of mounting my TBolt to a 2U 19 rack
 enclosure and was looking for a decent power supply. I found the Cisco unit
 and I am ordering a couple of them just in case. It would really be nice if
 I could have access to the diagram of the upgrade you did on yours to
 recreate the same performance from the Cisco unit. Please do not feel
 compromised if it is difficult to share. I didn't mean to be rude and if my
 note causes you any discomfort please kindly disregard it. I jumped into
 the thread because of experiencing the same doubts as the originator of it.

 Redondo Beach? I love visiting there whenever visiting my brother who
 lives in Rancho Palos Verdes. I would invite you lunch anytime just for the
 pleasure of meeting you in person.

 Thank you.

 Regards,





 Edgardo Molina
 Dirección IPTEL

 www.iptel.net.mx

 T : 55 55 55202444
 M : 04455 20501854

 Piensa en Bits SA de CV



 Información anexa:




 CONFIDENCIALIDAD DE INFORMACION

 Este mensaje tiene carácter confidencial. Si usted no es el destinarario
 de este mensaje, le suplicamos se lo notifique al remitente mediante un
 correo electrónico y que borre el presente mensaje y sus anexos de su
 computadora sin retener una copia de los mismos. Queda estrictamente
 prohibido copiar este mensaje o hacer usode el para cualquier propósito o
 divulgar su en forma parcial o total su contenido. Gracias.


 NON-DISCLOSURE OF INFORMATION

 This email is strictly confidential and may also be privileged. If you are
 not the intended recipient please immediately advise the sender by replying
 to this e-mail and then deleting the message and its attachments from your
 computer without keeping a copy. It is strictly forbidden to copy it or use
 it for any purpose or disclose its contents to any third party. Thank you.





 On Aug 25, 2012, at 3:26 PM, Chris Albertson albertson.ch...@gmail.com
 wrote:

  On Sat, Aug 25, 2012 at 1:06 PM, Jerry jster...@att.net wrote:
 
  I am using a Cisco supply 3 voltage supply for the T-bolt.  Is there any
  performance loss if the +12vdc rail and the -12vdc rail are off by a
 few %
  in opposite directions, e,g  +11.7 vdc and -12.3vdc ?
 
  The true nuts here on the time nuts list will tell you that the noise
 from
  a switching power supply is bad and that you need a regulated linear
 power
  supply.   But for most practical purposes the Cisco supply is a good one.
  Being only slightly nuts myself.  I use the Cisco   supply but I built a
  small power adaptor board with matching connectors and some pi filters
  made with RF choke and capacitors.  I realy don't thing the filters are
  needed but I wanted a connectorized installation and a small choke was as
  easy to solder in as a length of wire.
 
  --
 
  Chris Albertson
  Redondo Beach, California
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  To unsubscribe, go to
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-- 

Chris Albertson
Redondo Beach, California
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Re: [time-nuts] newbie question Thunderbolt supply

[Bob Camp]

Hi

The easy way to do a TBolt supply is to start with something between 15 and 18 
volts.  Regulate down to 12 and 5 with linear regulators. 7805's are fine for 
the +5. Something like a LT1764 might be better for the +12. The -12 supply is 
very low current and does not matter much. People have had good luck with 
voltage inversion chips off the +15 and then something like a 79L12.

Bob

On Aug 25, 2012, at 6:41 PM, Edgardo Molina xe1...@amsat.org wrote:

 Dear Chris,
 
 Good afternoon. I am in the process of mounting my TBolt to a 2U 19 rack 
 enclosure and was looking for a decent power supply. I found the Cisco unit 
 and I am ordering a couple of them just in case. It would really be nice if I 
 could have access to the diagram of the upgrade you did on yours to recreate 
 the same performance from the Cisco unit. Please do not feel compromised if 
 it is difficult to share. I didn't mean to be rude and if my note causes you 
 any discomfort please kindly disregard it. I jumped into the thread because 
 of experiencing the same doubts as the originator of it. 
 
 Redondo Beach? I love visiting there whenever visiting my brother who lives 
 in Rancho Palos Verdes. I would invite you lunch anytime just for the 
 pleasure of meeting you in person.
 
 Thank you.
 
 Regards,
 
 
 
 
 
 Edgardo Molina
 Dirección IPTEL
 
 www.iptel.net.mx
 
 T : 55 55 55202444
 M : 04455 20501854
 
 Piensa en Bits SA de CV
 
 
 
 Información anexa:
 
 
 
 
 CONFIDENCIALIDAD DE INFORMACION
 
 Este mensaje tiene carácter confidencial. Si usted no es el destinarario de 
 este mensaje, le suplicamos se lo notifique al remitente mediante un correo 
 electrónico y que borre el presente mensaje y sus anexos de su computadora 
 sin retener una copia de los mismos. Queda estrictamente prohibido copiar 
 este mensaje o hacer usode el para cualquier propósito o divulgar su en forma 
 parcial o total su contenido. Gracias.
 
 
 NON-DISCLOSURE OF INFORMATION
 
 This email is strictly confidential and may also be privileged. If you are 
 not the intended recipient please immediately advise the sender by replying 
 to this e-mail and then deleting the message and its attachments from your 
 computer without keeping a copy. It is strictly forbidden to copy it or use 
 it for any purpose or disclose its contents to any third party. Thank you.
 
 
 
 
 
 On Aug 25, 2012, at 3:26 PM, Chris Albertson albertson.ch...@gmail.com 
 wrote:
 
 On Sat, Aug 25, 2012 at 1:06 PM, Jerry jster...@att.net wrote:
 
 I am using a Cisco supply 3 voltage supply for the T-bolt.  Is there any
 performance loss if the +12vdc rail and the -12vdc rail are off by a few %
 in opposite directions, e,g  +11.7 vdc and -12.3vdc ?
 
 The true nuts here on the time nuts list will tell you that the noise from
 a switching power supply is bad and that you need a regulated linear power
 supply.   But for most practical purposes the Cisco supply is a good one.
 Being only slightly nuts myself.  I use the Cisco   supply but I built a
 small power adaptor board with matching connectors and some pi filters
 made with RF choke and capacitors.  I realy don't thing the filters are
 needed but I wanted a connectorized installation and a small choke was as
 easy to solder in as a length of wire.
 
 -- 
 
 Chris Albertson
 Redondo Beach, California
 ___
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 To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
 and follow the instructions there.
 
 ___
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Re: [time-nuts] newbie question Thunderbolt supply

[Hal Murray]

li...@rtty.us said:
 The -12 supply is very low current and does not matter much.

Is the -12 used only for the RS-232, or is it also the negative supply to the 
DAC?  If the latter, the regulation and noise may be important.

I think I remember comments about it being used by the DAC.  Wasn't there 
some mention of the TBolt working with a dead -12 supply, but only as long as 
the DAC output was above 0.



-- 
These are my opinions.  I hate spam.




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Re: [time-nuts] newbie question Thunderbolt supply

[Bob Camp]

Hi

The -12 runs the RS-232 and the negative supply to the DAC buffer. As long as 
it's past about -7V everything works pretty well. With no negative supply the 
DAC may have issues. Most of the OCXOs run right around 0V….

Bob

On Aug 25, 2012, at 8:55 PM, Hal Murray hmur...@megapathdsl.net wrote:

 
 li...@rtty.us said:
 The -12 supply is very low current and does not matter much.
 
 Is the -12 used only for the RS-232, or is it also the negative supply to the 
 DAC?  If the latter, the regulation and noise may be important.
 
 I think I remember comments about it being used by the DAC.  Wasn't there 
 some mention of the TBolt working with a dead -12 supply, but only as long as 
 the DAC output was above 0.
 
 
 
 -- 
 These are my opinions.  I hate spam.
 
 
 
 
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Re: [time-nuts] newbie question Thunderbolt supply

[J. L. Trantham]

I would recommend a linear regulated supply rather than a 'switching'
supply.

Joe

-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of Arthur Dent
Sent: Saturday, August 25, 2012 9:25 PM
To: time-nuts@febo.com
Subject: [time-nuts] newbie question Thunderbolt supply


I think I remember comments about it being used by the DAC.  Wasn't there 
some mention of the TBolt working with a dead -12 supply, but only as long
as 
the DAC output was above 0.


That was the conclusion. Actually the units these Thunderbolts were removed 
from used -7VDC instead of -12VDC. Many Thunderbolts will operate with 
the -12VDC line grounded but it shouldn't be left floating. It wouldn't be a

good idea to run the Thunderbolt without some negative voltage on this line 
and where it's easy to find a triple output supply, why take the chance. The

+12VDC is mainly for the oven  and internal to the OXCO it goes to a 
+5VDC linear regulator for the oscillator circuit so the +12VDC isn't as 
critical as the +5VDC.

-Arthur
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Re: [time-nuts] Newbie questions

[Bruce Griffiths]

But the result disagrees with the manufacturer's specs for RG59.
There's an error somewhere in your measurement setup.
For example, it could be a time offset error (or even differing trigger 
levels with a sinewave input) between the time interval counter start 
and stop channels.


Bruce

Tom Duckworth wrote:

Magnus,

We've made this measurement using a 20 ps time interval counter and a 
GPS disciplined Rubidium frequency standard as the time base; making 
many concurrent measurements with no dead time between. The resultant 
measurement was very close to the 1 ns/ft benchmark with RG-59 (BNC 
connectors), 10 MHz source. So we felt ok with using the 1 ns/ft 
estimate.


Tom
Tom Duckworth
tomd...@comcast.net
- Original Message - From: Magnus Danielson 
mag...@rubidium.dyndns.org
To: Discussion of precise time and frequency measurement 
time-nuts@febo.com

Sent: Tuesday, January 05, 2010 7:26 PM
Subject: Re: [time-nuts] Newbie questions



Tom Duckworth wrote:

Jim,

We use a benchmark 1 ns per foot of coax (RG-59).


This sounds fast. The normal taxiometer is at 66% of speed of ligth 
in vaccum, which for 1 ns is about 3 dm so for the RG-59 that would 
be about 2 dm.


Some cables reach 78%, but RG-58 and RG-59 is down at normal 66%.

You could measure the delay by using a resistive splitter (50 ohms) 
and two cables (say a 2 foot and a three foot, each terminated at 
the far end with a 50 ohm pass through terminator). Drive the 
splitter with your 10 MHz signal and measure, at the far end, using 
an appropriate 2-channel scope or counter with the necessary 
resolution, the difference in time delay between the two, which will 
give you a pretty accurate delay per foot. Both cables should be the 
same coax type.


Being a time-nut, using time-interval counters or TDR would be my 
choice, but these tools/toys outnumbers the scopes...


Cheers,
Magnus

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Re: [time-nuts] Newbie questions

[David C. Partridge]

Except the 1nS/ft figure is a good approximation to C (speed of light in
vacuo).  In RG58, you would expect to see 0.66C or about that.

So 1nS for 8 of cable is a good ROT.   Or put the other way round, about
1.5nS per foot.

Dave 

-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of Tom Duckworth
Sent: 06 January 2010 02:23
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Newbie questions

Jim,

We use a benchmark 1 ns per foot of coax (RG-59).

You could measure the delay by using a resistive splitter (50 ohms) and two
cables (say a 2 foot and a three foot, each terminated at the far end with a
50 ohm pass through terminator). Drive the splitter with your 10 MHz signal
and measure, at the far end, using an appropriate 2-channel scope or counter
with the necessary resolution, the difference in time delay between the two,
which will give you a pretty accurate delay per foot. Both cables should be
the same coax type.

Tom
Tom Duckworth
tomd...@comcast.net
- Original Message -
From: Jim Mandaville z...@dakotacom.net
To: Discussion of precise time and frequency measurement 
time-nuts@febo.com
Sent: Tuesday, January 05, 2010 11:17 AM
Subject: [time-nuts] Newbie questions


I am new to the list (although lurking now a while) and also new to the 
more precise species of  frequency and time measurement.  I have recently 
powered up an LPro and a Thunderbolt, both of which appear to be working by

the book.  Connecting the TBolt to my scope external sync and the LPro as 
an unknown I see the pattern moving one division (cm) to the left in 295 
seconds with a 0.05 us-per-division setting on the scope (the fastest 
setting available).  This, if my newly-learned calculations are correct, 
indicates a difference of 1.7 X10-10 (0.0017 Hz).  This appears to be 
confirmed by my HP 5335A counter, which shows the LPRO 1or 2 thousandths of

a Hz low, using the TBolt as an external time source. An HP manual I have 
indicates that a low unknown pattern should be moving to the right, not the

left, on the scope, so this sort of puzzles me.

 I have a few questions that I'm hoping some of you more experienced hands 
 can help with:

 1.  Can someone tell me the meaning and significance of the Timing 
 Outputs numbers in the lower left corner of the TBolt monitor window? 
 (Mine right now is showing plus 3.75 ns and plus 0.01 ppb). The TBolt 
 manual does not describe these, although on one page it lists them as 
 estimates of UTC/GPS offsets.  Do these numbers show the difference 
 between my receiver outputs and the time being kept by my present 
 satellites?  Or is it the difference between my receiver outputs and 
 master gps time (somewhere)?  Neither of these?  The use of two decimal 
 places on nanoseconds implies great accuracy.  Is this obtained in 
 practice?  My ppb on 10 MHz usually lies between plus 0.1 and minus 0.1, 
 often hanging around 0.01 or 0.02.  I have not so far put in any 
 compensation for cable delay.

 If the TBolt knows what these differences are, why doesn't it just 
 factor them into its outputs?  Or does it?

 2.  What is a reasonable expectation of TBolt accuracy (at any given time 
 that I use it for measurement) for the 10 MHz relative to NIS? How 
 accurate would it be, say, 90 percent of the time? (Looking for just an 
 experienced guesstimate here).

 3.  What format do I use to put in pps nanoseconds compensation for cable 
 delay (I use about 19 feet of RG-58U).  I understand this should be a 
 negative number.

 4.  Does anyone know a way to force the 5335A counter to display another 
 decimal place in frequency measurements?  I am getting to 0.001 Hz by 
 using the mean of 100 counts function on the counter, but I think the 
 counter has at least one more digit available which I would like to use 
 when accuracy justifies it (e.g. when using the TBolt as an external time 
 source).

 Any comments and suggestions appreciated
 Jim, KF7A


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Re: [time-nuts] Newbie questions

[Bob Camp]

Hi

The 5335 is a pretty nice counter, you can use the math functions to get just 
about anything you want displayed. One simple example is to just subtract 10 
MHz from the count and display the difference. 

The problem you run into is overflow in the counter chip. Somewhere around 100 
seconds you run out of storage with a 10 MHz input. 

It's been *years* since I ran one, I could be off on the 100 seconds 

Most of the ones you see for sale have at at least one input channel blown 
out.. They are easy to fry and the front end chips aren't anything you can get 
off the shelf. 

Bob


On Jan 6, 2010, at 2:55 AM, Hal Murray wrote:

 
 z...@dakotacom.net said:
 4.  Does anyone know a way to force the 5335A counter to display
 another decimal place in frequency measurements?  I am getting to
 0.001 Hz by using the mean of 100 counts function on the counter,
 but I think the counter has at least one more digit available which I
 would like to use when accuracy justifies it (e.g. when using the
 TBolt as an external time source). 
 
 I've never used a 5335 but I have a 5334.
 
 How many digits are there on the display?  How many of them are you getting?
 
 With the 5334, you can get a few more digits by running for 100 seconds but 
 you can only see them via GPIB.
 
 In case you haven't noticed, many people on this list are happy with the 
 Prologix GPIB/USB gadget.
 
 
 -- 
 These are my opinions, not necessarily my employer's.  I hate spam.
 
 
 
 
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Re: [time-nuts] Newbie questions

[Magnus Danielson]

Tom Duckworth wrote:

Magnus,

We've made this measurement using a 20 ps time interval counter and a 
GPS disciplined Rubidium frequency standard as the time base; making 
many concurrent measurements with no dead time between. The resultant 
measurement was very close to the 1 ns/ft benchmark with RG-59 (BNC 
connectors), 10 MHz source. So we felt ok with using the 1 ns/ft estimate.


Well, I think you should reconsider. Theory says that

v = 1/sqrt(my*epsilon) = 1/sqrt(my_r * epsilon_r) * c

For a coaxial cable, we have the magnetic properties about the same as 
vacuum, so my_r = 1 is a fair approximation. RG-58 and RG-59 use solid 
polyethylene having epsilon_r = 2,25 and that cranks out as v = 0,66*c,

in agreement with tabulated values:

http://hyperphysics.phy-astr.gsu.edu/Hbase/tables/diel.html
http://www.epanorama.net/documents/wiring/coaxcable.html

Notice how foam-PE rates at 0,78*c rather than 0,66*c. This is due to 
the lower dielectric constant (about 1,64) of foam PE.


I think it this relationship is wellfounded. I use 2 dm/ns for coax and 
fiber myself for my reality check calculations and found good 
correlation with reality whenever I tried it.


Oh, did you use sine as waveform? A few different frequencies and/or 
amplitude would be good to ensure that biases could be canceled out. I 
do that for reality check myself. Swapping the cables is another.


You have to excuse me, but the value you have measured does not really 
correlate well with my experience or view of theory.


Cheers,
Magnus

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Re: [time-nuts] Newbie questions

[Magnus Danielson]

Bob Camp wrote:

Hi

The 5335 is a pretty nice counter, you can use the math functions to get just about anything you want displayed. One simple example is to just subtract 10 MHz from the count and display the difference. 


Indeed. The 5335 can display 12 digits but does not overflow the display 
as some other counters but display the 12 most significant digits. The 
math function allows you to remove the most significant digits in order 
to display more digits. Good math-functions is necessary for good 
counters, I regularly use them. Correctly used you may often crank out 
the numbers you are interested in fairly quickly.


The problem you run into is overflow in the counter chip. Somewhere around 100 seconds you run out of storage with a 10 MHz input. 


The Gate Time is specified from 100 ns to 10 Ms. I think the CPU handles 
the overflow flag in the MRC and clears it.


The Gate Time can be set up to 4 seconds on the front (I really love the 
directness of the Gate Adjust knob, miss that in many other counters) 
and about 1 second using GPIB GA command. There are three ways to get 
longer gate time, Manual Trigg on the front panel, External Arm input at 
the back and using the GO (Gate Open) and GC (Gate Close) GPIB commands.


The single shot resolution is about 1 ns, each of the interpolators is 
good for about 500 ps, but since they always combine the result is 1 ns.


While increased time-base will give increased frequency resolution, the 
stability of the reference time-base becomes an issue. To measure 
stability the way we like (Allan Deviation and friends) they vary with 
the gate-time (which we call tau in time-nut-speech), so a counters 
resolution can be expressed as resolution divided by tau as a single 
figure of merit (which is an oversimplification). Another figure of 
merit is the single-shot resolution, the time resolution for a single 
trigger event. There is actually the hardware resolution and that which 
includes trigger-jitter (which is more usefull). The SR-620 is at about 
25 ps, but the hardware counting is in units of 4 ps. These numbers 
correlate to some degree with the Allan Deviation of the instrument for 
shorter taus, but as taus is allowed to increase various limits kicks in.



It's been *years* since I ran one, I could be off on the 100 seconds 

Most of the ones you see for sale have at at least one input channel blown out.. They are easy to fry and the front end chips aren't anything you can get off the shelf. 


It's a nice bench-counter thought and is fairly flexible.

The HP5334A is the economy version of the HP5335A but has an additional 
feature which is usefull for time-nuts... the binary output dumps the 
unprocessed MRC values and can do that in a steady stream, allowing for 
time-stamp records to be recorded. Together with picket fence it allows 
a higher rate recording than the HP5335A.


Hmm, I have a HP5335A to repair. Probably the PSU.

Cheers,
Magnus

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Re: [time-nuts] Newbie questions

[Bob Camp]

Hi

Ahhh, that jogs a few of the tired old brain cells

You can run the gate off of the GPIB input to get all kinds of silly long
gates. Then you start to get into the cpu overflow issues. Since it's a MSB
overflow you can usually clean it up in software *if* you know it's
happening. 

Since the GPIB is simply telling the counter start about now and finish
it up now the accuracy of the GPIB timing does not get into the result. The
counter still uses it's time base as the standard of comparison.

Bob

-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of Magnus Danielson
Sent: Wednesday, January 06, 2010 9:28 AM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Newbie questions

Bob Camp wrote:
 Hi
 
 The 5335 is a pretty nice counter, you can use the math functions to get
just about anything you want displayed. One simple example is to just
subtract 10 MHz from the count and display the difference. 

Indeed. The 5335 can display 12 digits but does not overflow the display 
as some other counters but display the 12 most significant digits. The 
math function allows you to remove the most significant digits in order 
to display more digits. Good math-functions is necessary for good 
counters, I regularly use them. Correctly used you may often crank out 
the numbers you are interested in fairly quickly.

 The problem you run into is overflow in the counter chip. Somewhere around
100 seconds you run out of storage with a 10 MHz input. 

The Gate Time is specified from 100 ns to 10 Ms. I think the CPU handles 
the overflow flag in the MRC and clears it.

The Gate Time can be set up to 4 seconds on the front (I really love the 
directness of the Gate Adjust knob, miss that in many other counters) 
and about 1 second using GPIB GA command. There are three ways to get 
longer gate time, Manual Trigg on the front panel, External Arm input at 
the back and using the GO (Gate Open) and GC (Gate Close) GPIB commands.

The single shot resolution is about 1 ns, each of the interpolators is 
good for about 500 ps, but since they always combine the result is 1 ns.

While increased time-base will give increased frequency resolution, the 
stability of the reference time-base becomes an issue. To measure 
stability the way we like (Allan Deviation and friends) they vary with 
the gate-time (which we call tau in time-nut-speech), so a counters 
resolution can be expressed as resolution divided by tau as a single 
figure of merit (which is an oversimplification). Another figure of 
merit is the single-shot resolution, the time resolution for a single 
trigger event. There is actually the hardware resolution and that which 
includes trigger-jitter (which is more usefull). The SR-620 is at about 
25 ps, but the hardware counting is in units of 4 ps. These numbers 
correlate to some degree with the Allan Deviation of the instrument for 
shorter taus, but as taus is allowed to increase various limits kicks in.

 It's been *years* since I ran one, I could be off on the 100 seconds 
 
 Most of the ones you see for sale have at at least one input channel blown
out.. They are easy to fry and the front end chips aren't anything you can
get off the shelf. 

It's a nice bench-counter thought and is fairly flexible.

The HP5334A is the economy version of the HP5335A but has an additional 
feature which is usefull for time-nuts... the binary output dumps the 
unprocessed MRC values and can do that in a steady stream, allowing for 
time-stamp records to be recorded. Together with picket fence it allows 
a higher rate recording than the HP5335A.

Hmm, I have a HP5335A to repair. Probably the PSU.

Cheers,
Magnus

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Re: [time-nuts] Newbie questions

[Bob Camp]

Hi

The thing that always gets me is when I pick up a piece of air dielectric
coax (like a line stretcher). I have to recalibrate all over again

Bob

-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of Magnus Danielson
Sent: Wednesday, January 06, 2010 8:17 AM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Newbie questions

Tom Duckworth wrote:
 Magnus,
 
 We've made this measurement using a 20 ps time interval counter and a 
 GPS disciplined Rubidium frequency standard as the time base; making 
 many concurrent measurements with no dead time between. The resultant 
 measurement was very close to the 1 ns/ft benchmark with RG-59 (BNC 
 connectors), 10 MHz source. So we felt ok with using the 1 ns/ft estimate.

Well, I think you should reconsider. Theory says that

v = 1/sqrt(my*epsilon) = 1/sqrt(my_r * epsilon_r) * c

For a coaxial cable, we have the magnetic properties about the same as 
vacuum, so my_r = 1 is a fair approximation. RG-58 and RG-59 use solid 
polyethylene having epsilon_r = 2,25 and that cranks out as v = 0,66*c,
in agreement with tabulated values:

http://hyperphysics.phy-astr.gsu.edu/Hbase/tables/diel.html
http://www.epanorama.net/documents/wiring/coaxcable.html

Notice how foam-PE rates at 0,78*c rather than 0,66*c. This is due to 
the lower dielectric constant (about 1,64) of foam PE.

I think it this relationship is wellfounded. I use 2 dm/ns for coax and 
fiber myself for my reality check calculations and found good 
correlation with reality whenever I tried it.

Oh, did you use sine as waveform? A few different frequencies and/or 
amplitude would be good to ensure that biases could be canceled out. I 
do that for reality check myself. Swapping the cables is another.

You have to excuse me, but the value you have measured does not really 
correlate well with my experience or view of theory.

Cheers,
Magnus

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Re: [time-nuts] Newbie questions

[Magnus Danielson]

Hi!

Bob Camp wrote:

Hi

Ahhh, that jogs a few of the tired old brain cells

You can run the gate off of the GPIB input to get all kinds of silly long
gates. Then you start to get into the cpu overflow issues. Since it's a MSB
overflow you can usually clean it up in software *if* you know it's
happening. 


Notice that it is specified to support gate-times up to 10 Ms (10^7 s). 
I would suspect that both the event and time counters is CPU extended.


Maybe I should pull the PROM and do a readout.


Since the GPIB is simply telling the counter start about now and finish
it up now the accuracy of the GPIB timing does not get into the result. The
counter still uses it's time base as the standard of comparison.


Well, it will cause a variation in gate-time (about 2 ms can be assumed, 
since that is what programmed gate using GA allows) , but since this is 
used for longer gate times it is not significant. If better precission 
is needed, the external arm input shall be used.


Cheers,
Magnus

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Re: [time-nuts] Newbie questions

[Bob Camp]

Hi

I agree with you on the spec sheet and the fact that the cpu *should* extend
the data. My observation was that it didn't do it if the input frequency was
high enough. I tried it on a couple dozen counters built over a period of
several years.

Bob

-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of Magnus Danielson
Sent: Wednesday, January 06, 2010 12:10 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Newbie questions

Hi!

Bob Camp wrote:
 Hi
 
 Ahhh, that jogs a few of the tired old brain cells
 
 You can run the gate off of the GPIB input to get all kinds of silly long
 gates. Then you start to get into the cpu overflow issues. Since it's a
MSB
 overflow you can usually clean it up in software *if* you know it's
 happening. 

Notice that it is specified to support gate-times up to 10 Ms (10^7 s). 
I would suspect that both the event and time counters is CPU extended.

Maybe I should pull the PROM and do a readout.

 Since the GPIB is simply telling the counter start about now and finish
 it up now the accuracy of the GPIB timing does not get into the result.
The
 counter still uses it's time base as the standard of comparison.

Well, it will cause a variation in gate-time (about 2 ms can be assumed, 
since that is what programmed gate using GA allows) , but since this is 
used for longer gate times it is not significant. If better precission 
is needed, the external arm input shall be used.

Cheers,
Magnus

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Re: [time-nuts] Newbie questions

[Magnus Danielson]

Bob Camp wrote:

Hi

I agree with you on the spec sheet and the fact that the cpu *should* extend
the data. My observation was that it didn't do it if the input frequency was
high enough. I tried it on a couple dozen counters built over a period of
several years.


That would imply that only the time counter is CPU extended, but not the 
event counter. This is kind of fair, since it allows the lower 
frequencies to gather equalent amount of events as higher frequencies 
and thus similar precission achieved.


Should be a simple exercise to establish the event overflow properties.

I have not seen any detailed description of the MRC chip, but I know it 
is being used in HP5315A, HP5316A, HP5334A and HP5335A. The later two 
are bigger counters which includes the interpolators for 1 ns 
resolution versus the 100 ns time resolution of the simpler units when 
using the 10 MHz directly. The MRC chip tolerates 100 MHz directly, so 
for the 200 MHz (1/2) and 1,3 GHz (1/20) responses prescalers is used.


Thus, the time counter ticks at 10 MHz while the event counter ticks at 
up to 100 MHz for normal frequency measurement. For frequency 
comparision, the time counter is being used for the B channel, so it can 
tick at 100 MHz then.


Cheers,
Magnus

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Re: [time-nuts] Newbie questions

[Bob Camp]

Hi

I have a pile of 5334's in the shed. I'm getting the itch to pull them out
and see what they can do. I've always looked down on them a bit, since
5335's were always available for what I needed to do.

Bob

-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of Magnus Danielson
Sent: Wednesday, January 06, 2010 12:41 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Newbie questions

Bob Camp wrote:
 Hi
 
 I agree with you on the spec sheet and the fact that the cpu *should*
extend
 the data. My observation was that it didn't do it if the input frequency
was
 high enough. I tried it on a couple dozen counters built over a period of
 several years.

That would imply that only the time counter is CPU extended, but not the 
event counter. This is kind of fair, since it allows the lower 
frequencies to gather equalent amount of events as higher frequencies 
and thus similar precission achieved.

Should be a simple exercise to establish the event overflow properties.

I have not seen any detailed description of the MRC chip, but I know it 
is being used in HP5315A, HP5316A, HP5334A and HP5335A. The later two 
are bigger counters which includes the interpolators for 1 ns 
resolution versus the 100 ns time resolution of the simpler units when 
using the 10 MHz directly. The MRC chip tolerates 100 MHz directly, so 
for the 200 MHz (1/2) and 1,3 GHz (1/20) responses prescalers is used.

Thus, the time counter ticks at 10 MHz while the event counter ticks at 
up to 100 MHz for normal frequency measurement. For frequency 
comparision, the time counter is being used for the B channel, so it can 
tick at 100 MHz then.

Cheers,
Magnus

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Re: [time-nuts] Newbie questions

[SAIDJACK]

On the 5334, you can get 11 digits resolution on the LED display  by 
subtracting 10MHz from the measurement (-10MHz offset), and setting the  
mesurement intervall to 99 seconds. Both sources need to be 10MHz of course for 
 this 
to work.
 
On the 5335 I seem to get one digit less with the same offset procedure, I  
could never get it to display 1E-011 digits..
 
bye,
Said
 
 
In a message dated 1/5/2010 23:55:56 Pacific Standard Time,  
hmur...@megapathdsl.net writes:


I've  never used a 5335 but I have a 5334.

How many digits are there on the  display?  How many of them are you 
getting?

With the 5334, you can  get a few more digits by running for 100 seconds 
but 
you can only see them  via GPIB.

In case you haven't noticed, many people on this list are  happy with the 
Prologix GPIB/USB  gadget.


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Re: [time-nuts] Newbie questions

[John Ackermann N8UR]

Bob Camp wrote:

Hi

I have a pile of 5334's in the shed. I'm getting the itch to pull them out
and see what they can do. I've always looked down on them a bit, since
5335's were always available for what I needed to do.


I've always liked the 5334s for both general bench use, and as TICs 
where 2ns resolution will do.  One advantage is that they don't have a 
fan to make yet more noise in the lab.


John

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Re: [time-nuts] Newbie questions

[Bob Camp]

Hi

Another thing in their favor is that they are smaller than a 5360, 5345, or a 
5335. You can stack more of them in the same space 

Bob


On Jan 6, 2010, at 1:39 PM, John Ackermann N8UR wrote:

 Bob Camp wrote:
 Hi
 I have a pile of 5334's in the shed. I'm getting the itch to pull them out
 and see what they can do. I've always looked down on them a bit, since
 5335's were always available for what I needed to do.
 
 I've always liked the 5334s for both general bench use, and as TICs where 2ns 
 resolution will do.  One advantage is that they don't have a fan to make yet 
 more noise in the lab.
 
 John
 
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Re: [time-nuts] Newbie questions

[Bruce Griffiths]

One should of course be aware that the number notation used is no longer 
considered correct.


Also even after correcting for the non standard notation the last set of 
numbers is incorrect:


eg
40.000 000 003 GHz  is equivalent to an error of  +7.5 parts in 1E11 not 
7.5 parts in 1E-11.


Bruce

Tom Duckworth wrote:

Jim,

Attached is some info on how to measure/calibrate a time base or 
oscillator which you might find useful per your e-mail.


Tom
Tom Duckworth
tomd...@comcast.net
- Original Message - From: Jim Mandaville z...@dakotacom.net
To: Discussion of precise time and frequency measurement 
time-nuts@febo.com

Sent: Tuesday, January 05, 2010 11:17 AM
Subject: [time-nuts] Newbie questions


I am new to the list (although lurking now a while) and also new to 
the more precise species of  frequency and time measurement.  I have 
recently powered up an LPro and a Thunderbolt, both of which appear 
to be working by the book.  Connecting the TBolt to my scope external 
sync and the LPro as an unknown I see the pattern moving one 
division (cm) to the left in 295 seconds with a 0.05 us-per-division 
setting on the scope (the fastest setting available).  This, if my 
newly-learned calculations are correct, indicates a difference of 1.7 
X10-10 (0.0017 Hz).  This appears to be confirmed by my HP 5335A 
counter, which shows the LPRO 1or 2 thousandths of a Hz low, using 
the TBolt as an external time source. An HP manual I have indicates 
that a low unknown pattern should be moving to the right, not the 
left, on the scope, so this sort of puzzles me.


I have a few questions that I'm hoping some of you more experienced 
hands can help with:


1.  Can someone tell me the meaning and significance of the Timing 
Outputs numbers in the lower left corner of the TBolt monitor 
window? (Mine right now is showing plus 3.75 ns and plus 0.01 ppb). 
The TBolt manual does not describe these, although on one page it 
lists them as estimates of UTC/GPS offsets.  Do these numbers show 
the difference between my receiver outputs and the time being kept by 
my present satellites?  Or is it the difference between my receiver 
outputs and master gps time (somewhere)?  Neither of these?  The use 
of two decimal places on nanoseconds implies great accuracy.  Is this 
obtained in practice?  My ppb on 10 MHz usually lies between plus 0.1 
and minus 0.1, often hanging around 0.01 or 0.02.  I have not so far 
put in any compensation for cable delay.


If the TBolt knows what these differences are, why doesn't it just 
factor them into its outputs?  Or does it?


2.  What is a reasonable expectation of TBolt accuracy (at any given 
time that I use it for measurement) for the 10 MHz relative to NIS? 
How accurate would it be, say, 90 percent of the time? (Looking for 
just an experienced guesstimate here).


3.  What format do I use to put in pps nanoseconds compensation for 
cable delay (I use about 19 feet of RG-58U).  I understand this 
should be a negative number.


4.  Does anyone know a way to force the 5335A counter to display 
another decimal place in frequency measurements?  I am getting to 
0.001 Hz by using the mean of 100 counts function on the counter, 
but I think the counter has at least one more digit available which I 
would like to use when accuracy justifies it (e.g. when using the 
TBolt as an external time source).


Any comments and suggestions appreciated
Jim, KF7A


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Re: [time-nuts] Newbie questions

[WarrenS]

Interesting

So a 100% error (1e2) would then be 40.4GHz and not 80GHz
Sounds like some new  math the cost of living department came up with.

ws

**

Bruce Griffiths bruce.griffiths at xtra.co.nz 
Tue Jan 5 20:25:05 UTC 2010 

One should of course be aware that the number notation used is no longer 
considered correct.

Also even after correcting for the non standard notation the last set of 
numbers is incorrect:

eg
40.000 000 003 GHz  is equivalent to an error of  +7.5 parts in 1E11 not 
7.5 parts in 1E-11.

Bruce
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Re: [time-nuts] Newbie questions

[John Miles]

 1.  Can someone tell me the meaning and significance of the Timing
 Outputs numbers in the lower left corner of the TBolt monitor
 window?  (Mine right now is showing plus 3.75 ns and plus 0.01 ppb).
 The TBolt manual does not describe these, although on one page it
 lists them as estimates of UTC/GPS offsets.  Do these numbers show
 the difference between my receiver outputs and the time being kept by
 my present satellites?  Or is it the difference between my receiver
 outputs and master gps time (somewhere)?  Neither of these?

They're basically what the manual says -- estimates of the current
oscillator performance versus what the Thunderbolt thinks the satellites are
telling it.

 The use
 of two decimal places on nanoseconds implies great accuracy.  Is this
 obtained in practice?  My ppb on 10 MHz usually lies between plus 0.1
 and minus 0.1, often hanging around 0.01 or 0.02.  I have not so far
 put in any compensation for cable delay.

To be meaningful, the reported data should ideally be filtered with a time
constant close to the VCO disciplining time constant, which you can do in
Lady Heather but not TBoltMon.  If not, it will seem artificially noisy.
Without filtering I don't think I'd pay much attention to the LSD (1E-11)
and possibly the next one (1E-10).

 If the TBolt knows what these differences are, why doesn't it just
 factor them into its outputs?  Or does it?

This is basically what happens, but it has to be done through the VCO
control loop's filter, which is a lowpass function (integrator) whose time
constant is typically 100 to 1000 seconds.

You can't get good clean timing data from GPS satellites at timescales much
shorter than that; the performance of your local OCXO will always be better.
You can set your disciplining time constant to 1 second and let the
Thunderbolt try to jerk the OCXO around as needed to zero out the reported
PPS and/or frequency error... but the actual result, if measured
independently at the Thunderbolt's 1-pps and 10 MHz outputs, will be fairly
noisy.

The situation is basically that of a PLL with a very good VCO (your OCXO)
and a noisy reference (the GPS signal).  Such cases call for long loop time
constants.

 2.  What is a reasonable expectation of TBolt accuracy (at any given
 time that I use it for measurement) for the 10 MHz relative to NIS?
 How accurate would it be, say, 90 percent of the time? (Looking for
 just an experienced guesstimate here).

This sort of question can't be answered without specifying the timescale,
which is why you commonly see people discussing Allan deviation and other
graph-friendly representations.  If you gather statistics once a day, the
answer is very accurate indeed, down in the parts per 1E14, thanks to GPS.
At shorter timescales the accuracy will be worse, again because of the
compromise between GPS S/N ratio and your local OCXO's stability.  Tom's
pages at http://www.leapsecond.com/pages/gpsdo/ and
http://www.leapsecond.com/pages/tbolt-8d/ are _extremely_ informative in
this regard.

 3.  What format do I use to put in pps nanoseconds compensation for
 cable delay (I use about 19 feet of RG-58U).  I understand this
 should be a negative number.

Not sure, never used this feature.  If you aren't trying to synchronize your
1-PPS output with other stations, there's not much point.

 4.  Does anyone know a way to force the 5335A counter to display
 another decimal place in frequency measurements?  I am getting to
 0.001 Hz by using the mean of 100 counts function on the counter,
 but I think the counter has at least one more digit available which I
 would like to use when accuracy justifies it (e.g. when using the
 TBolt as an external time source).

Unfortunately you can't even do that. :(  The counter's jitter and
resolution limits will dominate the performance of a GPSDO at timescales 
100 seconds or so.  Averaging isn't as informative as you might think,
because you don't know if the noise being averaged out is drift from the
DUT, phase noise from the DUT, quantization artifacts from the counter,
jitter from the counter, or all of the above.  (Hint: it's pretty much all
from the counter in this case.)

The best conventional time-interval counters have resolution+jitter floors
in the 20-50 ps neighborhood.  So stability measurements at 1-second
intervals can't be made below 20-50 parts per trillion with these
counters and traditional frequency counters are much worse.
Meanwhile, a Thunderbolt-class GPSDO will normally be accurate to better
than 10 parts per trillion at 1-second timescales (again, see Tom's pages).

Characterizing the stability of these sources requires specialized hardware
(which can be primarily digital or analog-based.)  Even with a better timing
analyzer, you'll eventually find that your LPRO is noisier than the
Thunderbolt at shorter timescales as well.

Use of a microwave synthesizer and counter, as in the document TomD
mentioned, isn't likely to be beneficial, because what's the first 

Re: [time-nuts] Newbie questions

[Tom Duckworth]

Warren- No, a 100% error would be 40 GHz. Where did you get 40.4 GHz? That 
would be 101% and of course 80 GHz is 200%.


Bruce- Of course you are right about the + symbol for 40.000 000 003 GHz 
(+7.5 parts in 1E-11) but what would you consider current standard notation. 
We still Use this metric notation in the US. What do you use?


Tom
Tom Duckworth
tomd...@comcast.net
- Original Message - 
From: WarrenS warrensjmail-...@yahoo.com
To: Discussion of precise time and frequency measurement 
time-nuts@febo.com

Sent: Tuesday, January 05, 2010 1:30 PM
Subject: Re: [time-nuts] Newbie questions



Interesting

So a 100% error (1e2) would then be 40.4GHz and not 80GHz
Sounds like some new  math the cost of living department came up with.

ws

**

Bruce Griffiths bruce.griffiths at xtra.co.nz
Tue Jan 5 20:25:05 UTC 2010

One should of course be aware that the number notation used is no longer
considered correct.

Also even after correcting for the non standard notation the last set of
numbers is incorrect:

eg
40.000 000 003 GHz  is equivalent to an error of  +7.5 parts in 1E11 not
7.5 parts in 1E-11.

Bruce
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Re: [time-nuts] Newbie questions

[John Ackermann N8UR]

Tom Duckworth said the following on 01/05/2010 09:10 PM:
Warren- No, a 100% error would be 40 GHz. Where did you get 40.4 GHz? 
That would be 101% and of course 80 GHz is 200%.


Bruce- Of course you are right about the + symbol for 40.000 000 003 GHz 
(+7.5 parts in 1E-11) but what would you consider current standard 
notation. We still Use this metric notation in the US. What do you use?


In the *extremely* pedantic department, I think you would refer to +7.5 
parts in 10e11 or to an offset of 7.5x10e-11.  When you're talking 
parts in something you use a positive exponent since you are referring 
to how large a population it takes to get 7.5 whole units.  When talking 
about fractional frequency offset, you use a negative exponent since 
you're referring to a fraction of a unit.  (There's probably a much 
better way to describe it.)


As I said, it's a very pedantic distinction...

John

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Re: [time-nuts] Newbie questions

[Tom Duckworth]

Jim,

We use a benchmark 1 ns per foot of coax (RG-59).

You could measure the delay by using a resistive splitter (50 ohms) and two 
cables (say a 2 foot and a three foot, each terminated at the far end with a 
50 ohm pass through terminator). Drive the splitter with your 10 MHz signal 
and measure, at the far end, using an appropriate 2-channel scope or counter 
with the necessary resolution, the difference in time delay between the two, 
which will give you a pretty accurate delay per foot. Both cables should be 
the same coax type.


Tom
Tom Duckworth
tomd...@comcast.net
- Original Message - 
From: Jim Mandaville z...@dakotacom.net
To: Discussion of precise time and frequency measurement 
time-nuts@febo.com

Sent: Tuesday, January 05, 2010 11:17 AM
Subject: [time-nuts] Newbie questions


I am new to the list (although lurking now a while) and also new to the 
more precise species of  frequency and time measurement.  I have recently 
powered up an LPro and a Thunderbolt, both of which appear to be working by 
the book.  Connecting the TBolt to my scope external sync and the LPro as 
an unknown I see the pattern moving one division (cm) to the left in 295 
seconds with a 0.05 us-per-division setting on the scope (the fastest 
setting available).  This, if my newly-learned calculations are correct, 
indicates a difference of 1.7 X10-10 (0.0017 Hz).  This appears to be 
confirmed by my HP 5335A counter, which shows the LPRO 1or 2 thousandths of 
a Hz low, using the TBolt as an external time source. An HP manual I have 
indicates that a low unknown pattern should be moving to the right, not the 
left, on the scope, so this sort of puzzles me.


I have a few questions that I'm hoping some of you more experienced hands 
can help with:


1.  Can someone tell me the meaning and significance of the Timing 
Outputs numbers in the lower left corner of the TBolt monitor window? 
(Mine right now is showing plus 3.75 ns and plus 0.01 ppb). The TBolt 
manual does not describe these, although on one page it lists them as 
estimates of UTC/GPS offsets.  Do these numbers show the difference 
between my receiver outputs and the time being kept by my present 
satellites?  Or is it the difference between my receiver outputs and 
master gps time (somewhere)?  Neither of these?  The use of two decimal 
places on nanoseconds implies great accuracy.  Is this obtained in 
practice?  My ppb on 10 MHz usually lies between plus 0.1 and minus 0.1, 
often hanging around 0.01 or 0.02.  I have not so far put in any 
compensation for cable delay.


If the TBolt knows what these differences are, why doesn't it just 
factor them into its outputs?  Or does it?


2.  What is a reasonable expectation of TBolt accuracy (at any given time 
that I use it for measurement) for the 10 MHz relative to NIS? How 
accurate would it be, say, 90 percent of the time? (Looking for just an 
experienced guesstimate here).


3.  What format do I use to put in pps nanoseconds compensation for cable 
delay (I use about 19 feet of RG-58U).  I understand this should be a 
negative number.


4.  Does anyone know a way to force the 5335A counter to display another 
decimal place in frequency measurements?  I am getting to 0.001 Hz by 
using the mean of 100 counts function on the counter, but I think the 
counter has at least one more digit available which I would like to use 
when accuracy justifies it (e.g. when using the TBolt as an external time 
source).


Any comments and suggestions appreciated
Jim, KF7A


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Re: [time-nuts] Newbie questions

[Bruce Griffiths]

IE-11 is probably more current notation than using 10E-11 for 1 part in 
1 hundred thousand million.

However this is only to be expected from oder application notes and papers.

Tom Duckworth wrote:
Warren- No, a 100% error would be 40 GHz. Where did you get 40.4 GHz? 
That would be 101% and of course 80 GHz is 200%.


He's just using the same perverse logic that produced the last set of 
numbers on the application note.


Bruce
Bruce- Of course you are right about the + symbol for 40.000 000 003 
GHz (+7.5 parts in 1E-11) but what would you consider current standard 
notation. We still Use this metric notation in the US. What do you use?


Tom
Tom Duckworth
tomd...@comcast.net
- Original Message - From: WarrenS warrensjmail-...@yahoo.com
To: Discussion of precise time and frequency measurement 
time-nuts@febo.com

Sent: Tuesday, January 05, 2010 1:30 PM
Subject: Re: [time-nuts] Newbie questions



Interesting

So a 100% error (1e2) would then be 40.4GHz and not 80GHz
Sounds like some new  math the cost of living department came up with.

ws

**

Bruce Griffiths bruce.griffiths at xtra.co.nz
Tue Jan 5 20:25:05 UTC 2010

One should of course be aware that the number notation used is no longer
considered correct.

Also even after correcting for the non standard notation the last set of
numbers is incorrect:

eg
40.000 000 003 GHz  is equivalent to an error of  +7.5 parts in 1E11 not
7.5 parts in 1E-11.

Bruce
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Re: [time-nuts] Newbie questions

[Jim Mandaville]

Run away while you still can? :-P

-- john, KE5FX



Nope, not ready to run away by any means, John!  And I do thank you 
much for your time in these helpful comments.  Thanks also to Tom for 
that somewhat different scope method.  I was indeed wondering about 
that short-term stability issue  when making quick point-in-time 
frequency measurements.  You have clarified my thinking on this.  My 
conclusion now is that there is not much point in trying to adjust 
the LPRO to the TBolt frequency when the difference, as now, is only 
0.001 or 0.002 Hz  I should just probably make comparisons once in a 
while to check the LPRO for aging rate, etc.


But what about making comparisons with the counter using very long 
gate times, such as 1000 seconds.  Wouldn't that make things more 
accurate.  Or would I still be limited by the counter (obviously I am 
still limited by the number of digits being displayed).


By the way, I noticed that the blurb for that just-announced (here) 
TBolt-disciplined LPRO is adjusted at the factory for down to 0.1 
ppb accuracy   That is just about the limit of accuracy I see for 
the indicated 10 MHz output on the TBolt monitor (although for much 
of the time mine seems to run somewhat better than that).


Jim


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Re: [time-nuts] Newbie questions

[John Miles]

 Nope, not ready to run away by any means, John!  And I do thank you
 much for your time in these helpful comments.  Thanks also to Tom for
 that somewhat different scope method.  I was indeed wondering about
 that short-term stability issue  when making quick point-in-time
 frequency measurements.  You have clarified my thinking on this.  My
 conclusion now is that there is not much point in trying to adjust
 the LPRO to the TBolt frequency when the difference, as now, is only
 0.001 or 0.002 Hz  I should just probably make comparisons once in a
 while to check the LPRO for aging rate, etc.

 But what about making comparisons with the counter using very long
 gate times, such as 1000 seconds.  Wouldn't that make things more
 accurate.  Or would I still be limited by the counter (obviously I am
 still limited by the number of digits being displayed).

You can use long gate times to measure long-term frequency differences, as
long as the counter has enough storage to accumulate that many cycles.  At
some point you may find that increasing the gate time doesn't give you any
more digits of precision.  Unfortunately I'm totally unfamiliar with the
5335A so can't say offhand what the best settings would be.

-- john, KE5FX



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Re: [time-nuts] Newbie questions

[Hal Murray]

mag...@rubidium.dyndns.org said:
 This sounds fast. The normal taxiometer is at 66% of speed of ligth in
  vaccum, which for 1 ns is about 3 dm so for the RG-59 that would be
 about 2 dm.

 Some cables reach 78%, but RG-58 and RG-59 is down at normal 66%. 

Sounds right.

My rule to thumb for back-of-envelope work is that a signal in fiber and good 
(but not nutty) coax goes 1 km while light in air/vacuum goes 1 mile.  In 
this context, good means foam rather than solid dielectric.

Light goes 1 ft/ns in air or 5000 ns per mile or 5 usec/mile.  In coax/fiber, 
that's 5 usec/km.



-- 
These are my opinions, not necessarily my employer's.  I hate spam.




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Re: [time-nuts] Newbie questions

[Hal Murray]

z...@dakotacom.net said:
 4.  Does anyone know a way to force the 5335A counter to display
 another decimal place in frequency measurements?  I am getting to
 0.001 Hz by using the mean of 100 counts function on the counter,
 but I think the counter has at least one more digit available which I
 would like to use when accuracy justifies it (e.g. when using the
 TBolt as an external time source). 

I've never used a 5335 but I have a 5334.

How many digits are there on the display?  How many of them are you getting?

With the 5334, you can get a few more digits by running for 100 seconds but 
you can only see them via GPIB.

In case you haven't noticed, many people on this list are happy with the 
Prologix GPIB/USB gadget.


-- 
These are my opinions, not necessarily my employer's.  I hate spam.




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Re: [time-nuts] Newbie questions

[Tom Duckworth]

Magnus,

We've made this measurement using a 20 ps time interval counter and a GPS 
disciplined Rubidium frequency standard as the time base; making many 
concurrent measurements with no dead time between. The resultant measurement 
was very close to the 1 ns/ft benchmark with RG-59 (BNC connectors), 10 MHz 
source. So we felt ok with using the 1 ns/ft estimate.


Tom
Tom Duckworth
tomd...@comcast.net
- Original Message - 
From: Magnus Danielson mag...@rubidium.dyndns.org
To: Discussion of precise time and frequency measurement 
time-nuts@febo.com

Sent: Tuesday, January 05, 2010 7:26 PM
Subject: Re: [time-nuts] Newbie questions



Tom Duckworth wrote:

Jim,

We use a benchmark 1 ns per foot of coax (RG-59).


This sounds fast. The normal taxiometer is at 66% of speed of ligth in 
vaccum, which for 1 ns is about 3 dm so for the RG-59 that would be about 
2 dm.


Some cables reach 78%, but RG-58 and RG-59 is down at normal 66%.

You could measure the delay by using a resistive splitter (50 ohms) and 
two cables (say a 2 foot and a three foot, each terminated at the far end 
with a 50 ohm pass through terminator). Drive the splitter with your 10 
MHz signal and measure, at the far end, using an appropriate 2-channel 
scope or counter with the necessary resolution, the difference in time 
delay between the two, which will give you a pretty accurate delay per 
foot. Both cables should be the same coax type.


Being a time-nut, using time-interval counters or TDR would be my choice, 
but these tools/toys outnumbers the scopes...


Cheers,
Magnus

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Re: [time-nuts] Newbie looking for GPSDO kit or Project sites

[Don Key]

There was also a project in Everyday Practical Electronics magazine for a 
GPS based frequency reference with 10MHz  1MHz outputs. Issues April  May 
09 had the frequency reference, and issue October 09 carried a project for a 
1PPS driver for an analogue quartz clock. If  I remember rightly, 1 or 2 
members had problems with jitter.


http://www.epemag3.com/index.php?option=com_virtuemartpage=shop.browsecategory_id=48Itemid=26

Both articles were reproduced from the Australian Silicon Chip magazine.

...Jim



-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of Ray Hudson
Sent: 13 October 2009 12:53
To: time-nuts@febo.com
Subject: [time-nuts] Newbie looking for GPSDO kit or Project sites
 Hi there; being a new Time nut I'm looking for kit/project web sites 
info on building a GPSDO PLL.
 Any info welcomed.
 Ta Ray.
 _

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Re: [time-nuts] Newbie looking for GPSDO kit or Project sites

[Dick Moore]

I present detailed experiences of building two different GPSDOs, which  
were built from designs with available PC boards. Visit my pages at:

www.moorepage.net

GPS oscillator 1 is Brooks Shera's PLL design. GPS oscillator 2 is  
Bertrand Zauhar's FLL design. I have links for lots of stuff in both.


Best,
Dick Moore

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Re: [time-nuts] Newbie looking for GPSDO kit or Project sites

[Roberto Barrios]

 

If you want to get your hands dirty, I'd suggest you to try VE2ZAZ's design. 
I've built a few GPSDOs and this one is the one I liked most.

 

http://ve2zaz.net/GPS_Std/GPS_Std.htm

 

Roberto

 

 

Date: Tue, 13 Oct 2009 13:30:10 +0100
From: David C. Partridge david.partri...@dsl.pipex.com
Subject: Re: [time-nuts] Newbie looking for GPSDO kit or Project sites
To: 'Discussion of precise time and frequency measurement'
time-nuts@febo.com
Message-ID: 7f8db3beeb144011940a58bdf82f3...@apollo
Content-Type: text/plain; charset=us-ascii
 
Do you actually want to build your own from scratch, or just buy something
like a Trimble Thunderbolt and add a PSU and housing?
 
If the latter then look for seller fluke.l (that's a lower case letter L)
on eBay if you should want one right now, or if you aren't in a hurry wait
for the next group buy of these here.
 
If the former, how sophisticated do you want to get? These beesties can go
from real simple:
 
http://www.jrmiller.demon.co.uk/projects/ministd/frqstd0.htm
 
to really moderately complex such as:
 
http://www.rt66.com/~shera/index_fs.htm
 
I'm sure there have probably been more recent designs too that have gotten
even smarter ...
 
Dave
 
-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of Ray Hudson
Sent: 13 October 2009 12:53
To: time-nuts@febo.com
Subject: [time-nuts] Newbie looking for GPSDO kit or Project sites
 
 
Hi there; being a new Time nut I'm looking for kit/project web sites 
info on building a GPSDO PLL.
 
Any info welcomed.
 
Ta Ray.
 
  
_

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Re: [time-nuts] Newbie looking for GPSDO kit or Project sites

[Luis Cupido]

Hi,

Depending how deep you want, to go you must
note that this one from ve2zaz (btw which is a great
design given it's simplicity) is a FLL not a PLL.
(unlike most of the others that really lock the phase of the
signal to the 10KHz or 1pps).

Luis Cupido.
ct1dmk.




Roberto Barrios wrote:
 


If you want to get your hands dirty, I'd suggest you to try VE2ZAZ's design. 
I've built a few GPSDOs and this one is the one I liked most.

 


http://ve2zaz.net/GPS_Std/GPS_Std.htm

 


Roberto

 

 


Date: Tue, 13 Oct 2009 13:30:10 +0100
From: David C. Partridge david.partri...@dsl.pipex.com
Subject: Re: [time-nuts] Newbie looking for GPSDO kit or Project sites
To: 'Discussion of precise time and frequency measurement'
time-nuts@febo.com
Message-ID: 7f8db3beeb144011940a58bdf82f3...@apollo
Content-Type: text/plain; charset=us-ascii
 
Do you actually want to build your own from scratch, or just buy something

like a Trimble Thunderbolt and add a PSU and housing?
 
If the latter then look for seller fluke.l (that's a lower case letter L)

on eBay if you should want one right now, or if you aren't in a hurry wait
for the next group buy of these here.
 
If the former, how sophisticated do you want to get? These beesties can go

from real simple:
 
http://www.jrmiller.demon.co.uk/projects/ministd/frqstd0.htm
 
to really moderately complex such as:
 
http://www.rt66.com/~shera/index_fs.htm
 
I'm sure there have probably been more recent designs too that have gotten

even smarter ...
 
Dave
 
-Original Message-

From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of Ray Hudson
Sent: 13 October 2009 12:53
To: time-nuts@febo.com
Subject: [time-nuts] Newbie looking for GPSDO kit or Project sites
 
 
Hi there; being a new Time nut I'm looking for kit/project web sites 

info on building a GPSDO PLL.
 
Any info welcomed.
 
Ta Ray.
 
 		 	   		  
_


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Re: [time-nuts] Newbie question - what use is a Ruby?

[Scott Burris]

Murray Greenman wrote:

4. They are a handy adjunct to the GPSDO. Use the latter to calibrate
the former, and then you've a reference even if GPS is unavailable. The
Rb units also have very good short-term stability.
  

So, how would you go about calibrating your Rubidium against your GPSDO?

Presumably you would wait until your GPSDO has not gone into holdover 
for some

good amount of time, whatever that would be.

Then my way would be to use the GPSDO as the external frequency reference to
either my Racal-Dana 1998 or HP5328A, apply the rubidium as input, and 
adjust
the C field for 10.0* Mhz. 

But I'm sure that's not the time-nuts way of doing this. :-)  So what's 
the right way?


Scott


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Re: [time-nuts] Newbie question - what use is a Ruby?

[Stijn]

Hal, you are mean!
That is about the way that i started with Time and Frequency, first a 
Z3801A and then a second one, then a rubidium and in the following a 
cesium standard. And further all the related measurement equipment.
Just because I wanted to know as a radio amateur that I was precisely on 
3705kHz in AM.
I must say it is very addictive and should be in considered equal to 
alcohol and drugs.


It is a terribel hobby, just the hunt for an extra digit.

Sincerely,

Stijn Nestra
PE1RKS

Scott Burris schreef:

Murray Greenman wrote:

4. They are a handy adjunct to the GPSDO. Use the latter to calibrate
the former, and then you've a reference even if GPS is unavailable. The
Rb units also have very good short-term stability.
  

So, how would you go about calibrating your Rubidium against your GPSDO?

Presumably you would wait until your GPSDO has not gone into holdover 
for some

good amount of time, whatever that would be.

Then my way would be to use the GPSDO as the external frequency 
reference to
either my Racal-Dana 1998 or HP5328A, apply the rubidium as input, and 
adjust

the C field for 10.0* Mhz.
But I'm sure that's not the time-nuts way of doing this. :-)  So what's 
the right way?


Scott


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Re: [time-nuts] Newbie question - what use is a Ruby?

[Magnus Danielson]

Scott Burris wrote:

Murray Greenman wrote:

4. They are a handy adjunct to the GPSDO. Use the latter to calibrate
the former, and then you've a reference even if GPS is unavailable. The
Rb units also have very good short-term stability.
  

So, how would you go about calibrating your Rubidium against your GPSDO?

Presumably you would wait until your GPSDO has not gone into holdover 
for some

good amount of time, whatever that would be.

Then my way would be to use the GPSDO as the external frequency 
reference to
either my Racal-Dana 1998 or HP5328A, apply the rubidium as input, and 
adjust

the C field for 10.0* Mhz.
But I'm sure that's not the time-nuts way of doing this. :-)  So what's 
the right way?


Use the time-interval mode of the counters, log the time-interval over 
time and adjust the C field until the long-term drift in time interval 
between the reference and the oscillator cancels out.


Requires some divide-down thing, like the TADD-2 divide-box. Use the 100 
kHz output when comparing to the PPS signal of say a Thunderbolt or 
whatever is available.


Cheers,
Magnus

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