date:20141216

Hi
 On Dec 15, 2014, at 11:20 PM, Dave M dgmin...@mediacombb.net wrote:
 
 Jim Lux wrote:
 On 12/15/14, 5:46 PM, Dave M wrote:
 With all the discussion about surveys  position accuracy, I have a
 question about my choke ring antenna.  There is an arrow marked N
 on the underside of the rings.  How accurately does the alignment
 need to be to North? True north or magnetic north (my thinking
 says True North)? Does the directional accuracy affect the precision 
 survey?  I'm
 assuming that it would have no effect on the accuracy of the 10 MHz
 frequency output. Or am I completely off base?
 
 
 If you're using a standard antenna, they've characterized them for the
 change in phase center with respect to the direction the signals are
 coming from. It's assumed you'll install it level, so elevation is
 taken care of.  The remaining uncertainty is the azimuth, hence the
 north arrow.
 
 Now we can find out how much of a nut you really are.  On choke ring
 antennas, I think the maximum shift in phase center with look
 direction is on the order of single digit millimeters, or a few ps.
 
 And how accurately do you know what direction is north.  That could
 be a whole project in itself, ranging from moss on trees, to shadows of
 sticks and rocks, to observations of Polaris through a theodolite, and
 so forth.
 
 
 
 Thanks for the explanations.  I'm not terribly concerned about time, other 
 than knowing when it's time to eat and sleep... I'm more of a frequency nut 
 than a time nut.  I have a USGS map and recent survey of my property, so I 
 know where North is, to a pretty good certainty.

Since the only way you get frequency is by processing time, you do indeed care 
about time if you are looking for frequency :)

That said, the error is indeed only a fixed offset and it would not matter in 
any time solution. There are much larger issues in a time solution. For a 
precision time application, you would locate the antenna first. Next you run a 
survey receiver through the same antenna. Once you process the results of the 
survey, it would take out any phase center error from the antenna. 

All that said, yes, it’s not worth worrying about in your case.

Bob

 
 Thanks!!
 Dave M
 
 
 
 
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Re: [time-nuts] GPS position averaging

Hi

 On Dec 15, 2014, at 9:39 PM, Paul tic-...@bodosom.net wrote:
 
 On Mon, Dec 15, 2014 at 8:35 PM, Bob Camp kb...@n1k.org wrote:
 
 So the question - If they are not going to be equal, which one do you pick?
 
 
 The better one.  If the math is sound the presumably the better position
 results in better time.
 If there are correlated defects then I suppose the GPS provided solution
 may be better.
 
 None of the various surveys for my primary antenna (which is not optimally
 located) agree and all are wrong compared to carrier phase solutions.
 The delta between the various units (Trimble, uBlox and whatever is in the
 Fury) is greater than the delta between my indoor and outdoor antenna
 positions in xy.  Z not so much.


I have seen cases where almost all the error is in Z and the X and Y agree 
quite well. My *guess* has been that most users don’t fly. The Z error is less 
of a problem for them. 

Numbers in the 10’ range are not at all uncommon. That’s enough to potentially  
add a 10 ns ripple to your data.

Bob

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Re: [time-nuts] Connections for FE-5680A rubidium sources

2014-12-16 Thread Dr. David Kirkby (Kirkby Microwave Ltd)

Hi

One fairly important issue - the unit needs to be on a heat sink. If you run it 
without cooling of some sort, it will not run for very many years.

Bob

 On Dec 16, 2014, at 5:22 AM, Dr. David Kirkby (Kirkby Microwave Ltd) 
 drkir...@kirkbymicrowave.co.uk wrote:
 
 I have a couple of Rb sources bought from China or Hong Kong a year or
 two ago. I'd like to fix these up. Initially in a box where I can
 adjust them to frequency manually, but perhaps later lock them to GPS.
 Looking around the web, there are countless options on these things,
 and different connection diagrams. Can anyone tell me what these are.
 I have attached a picture of one. I have doctored the picture ab bit
 so there are large arears of one shade, so the images compress quite a
 bit. Essentially they are rather dirty looking metal boxes with rather
 dirty white labels on, but such detail is not needed.
 
 The big label says:
 
 FE-5680A
 FEI P/N 217400-303520-1
 
 The smaller label with the barcode differs a bit between the two units.
 
 1)  FE-5680A UN 61391 S/N 02444-57246 (on the one I photographed)
 2)  FE-??80A UN 66794 S/N 0340-66253 (can't quite read all of it, but
 I assume the missing characters are 56.
 
 There is a small adjustment screw on the right, and a 9-pin
 D-connector, with the lead cut at about 40 mm from the connector.
 
 I can open one up and take a picture internally if need be.
 
 Dave
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Re: [time-nuts] Connections for FE-5680A rubidium sources

On 16 December 2014 at 12:16, Bob Camp kb...@n1k.org wrote:
 Hi

 One fairly important issue - the unit needs to be on a heat sink. If you run 
 it without cooling of some sort, it will not run for very many years.

 Bob

I do realize that, but how big? Normally the bigger the better is
not an unreasonable rule on heatsinks, but I have heard that cooling
these too much is bad. I have here a heatsink about 600 x 300 x 150
mm, although I think that is a bit OTT !!

Dave
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Re: [time-nuts] Connections for FE-5680A rubidium sources

Hi

You are dumping about 15W into the heat sink (or cooling system). You would 
like to keep the baseplate at  40C if possible. In a 25C room, that works out 
to a 1 C/W heat sink. If you are using a fan, that’s a pretty small gizmo. If 
you are building a metal case and putting other stuff in the box, the case wall 
might be good enough. The standard text book thermodynamic calculations apply 
if you want to go through all the math on this or that structure.

Bob

 On Dec 16, 2014, at 7:20 AM, Dr. David Kirkby (Kirkby Microwave Ltd) 
 drkir...@kirkbymicrowave.co.uk wrote:
 
 On 16 December 2014 at 12:16, Bob Camp kb...@n1k.org wrote:
 Hi
 
 One fairly important issue - the unit needs to be on a heat sink. If you run 
 it without cooling of some sort, it will not run for very many years.
 
 Bob
 
 I do realize that, but how big? Normally the bigger the better is
 not an unreasonable rule on heatsinks, but I have heard that cooling
 these too much is bad. I have here a heatsink about 600 x 300 x 150
 mm, although I think that is a bit OTT !!
 
 Dave
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Re: [time-nuts] Choke Rings and Points North

2014-12-16 Thread Dr. David Kirkby (Kirkby Microwave Ltd)


On 12/15/14, 8:10 PM, Tom Van Baak wrote:


But to prove us wrong, put the antenna on a 17 hour turn-table, collect data 
for 6 months, and then see if you see any 17h peaks in the FFT!



Clever idea, but..

Most rotary joints have more phase and amplitude variability than the 
antenna.


So you're stuck with rotating back and forth with a cable that's flexing 
and now you get to measure the phase variability of the coax.


You really need to have your entire GPS system antenna and receiver on 
the rotating table (which will need to have temperature controls, etc.)



Oh, what a pit one can descend into with the goal of reducing everything 
to a minimum error.





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Re: [time-nuts] Connections for FE-5680A rubidium sources

2014-12-16 Thread Bert Kehren via time-nuts

I suggest you go to http://www.febo.com/pipermail/time-nuts/  back a couple 
of years and you will find every thing you ever want to know about  the FE 
5680A. Similar to the recent Lucent activity
Bert Kehren



In a message dated 12/16/2014 7:21:02 A.M. Eastern Standard Time,  
drkir...@kirkbymicrowave.co.uk writes:

On 16  December 2014 at 12:16, Bob Camp kb...@n1k.org wrote:
  Hi

 One fairly important issue - the unit needs to be on a heat  sink. If you 
run it without cooling of some sort, it will not run for very  many years.

 Bob

I do realize that, but how big?  Normally the bigger the better is
not an unreasonable rule on heatsinks,  but I have heard that cooling
these too much is bad. I have here a heatsink  about 600 x 300 x 150
mm, although I think that is a bit OTT  !!

Dave
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Re: [time-nuts] Connections for FE-5680A rubidium sources

On 16 December 2014 at 13:18, Bert Kehren via time-nuts
time-nuts@febo.com wrote:
 I suggest you go to http://www.febo.com/pipermail/time-nuts/  back a couple
 of years and you will find every thing you ever want to know about  the FE
 5680A. Similar to the recent Lucent activity
 Bert Kehren

I did do that, and found various comments about various options, and
people note knowing what options they had. I'm in the same situation.
I was hoping someone would know more about this specific part, as
there seems to be a lot of variations on this.

Dave
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Re: [time-nuts] Choke Rings and Points North

2014-12-16 Thread Tom Van Baak

 Clever idea, but..
 
 Most rotary joints have more phase and amplitude variability than the 
 antenna.
 
 So you're stuck with rotating back and forth with a cable that's flexing 
 and now you get to measure the phase variability of the coax.

I was thinking of some sort of non-contact RF bridge that would allow either 
side to rotate independently. Converting to optical would make this easy, but 
there must be a way to do it at 1.5 GHz too.
 
 You really need to have your entire GPS system antenna and receiver on 
 the rotating table (which will need to have temperature controls, etc.)
 
 Oh, what a pit one can descend into with the goal of reducing everything 
 to a minimum error.

In this case the goal is actually not minimizing error. The goal is to vary 
each possible error source with its own prime modulation period. Collect lots 
of data and the FFT tells you how much each error contributes to the pie.

For example, instead of temperature control you modulate temperature by 5C over 
a 13 hour period. Instead of voltage control you modulate the 5V antenna power 
by 10% every 1.7 hours, etc.

/tvb
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Re: [time-nuts] Connections for FE-5680A rubidium sources


Dave wrote:


 I suggest you go to http://www.febo.com/pipermail/time-nuts/  back a couple
 of years and you will find every thing you ever want to know about  the FE
 5680A. Similar to the recent Lucent activity

I did do that, and found various comments about various options, and
people note knowing what options they had. I'm in the same situation.
I was hoping someone would know more about this specific part, as
there seems to be a lot of variations on this.


If you go back and actually read the discussions instead of just 
skimming them and deciding it's all noise, you will find all of your 
questions answered.  They're list posts -- lots of questions and 
speculation, and a few gems.  You need to persevere to find the gems.


Best regards,

Charles



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Re: [time-nuts] Choke Rings and Points North


On 12/16/14, 5:59 AM, Tom Van Baak wrote:

Clever idea, but..

Most rotary joints have more phase and amplitude variability than
the antenna.

So you're stuck with rotating back and forth with a cable that's
flexing and now you get to measure the phase variability of the
coax.


I was thinking of some sort of non-contact RF bridge that would allow
either side to rotate independently. Converting to optical would make
this easy, but there must be a way to do it at 1.5 GHz too.



two nested coils forming an air core transformer or slip rings are the
typical approach.
(Waveguide at 1.5 GHz is somewhat unwieldy in size).

The trick is in holding mechanical tolerances tight enough.I guess, 1mm
mechanical tolerance (easy, easy) would be comparable to the phase
center displacement.



You really need to have your entire GPS system antenna and receiver
on the rotating table (which will need to have temperature
controls, etc.)

Oh, what a pit one can descend into with the goal of reducing
everything to a minimum error.


In this case the goal is actually not minimizing error. The goal is
to vary each possible error source with its own prime modulation
period. Collect lots of data and the FFT tells you how much each
error contributes to the pie.


Yes, but how do you know whether it's coax flex or phase center 
displacement that's causing your 17 hour periodicity.


I was thinking not so much reducing error in the overall measurement, 
but in reducing the uncertainty in the estimate of the size of each 
contributor to the overall system.





For example, instead of temperature control you modulate temperature
by 5C over a 13 hour period. Instead of voltage control you modulate
the 5V antenna power by 10% every 1.7 hours, etc.


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Re: [time-nuts] Linear voltage regulator hints...


Dan wrote:

My gut feeling is you are right about the GPS time base being 
sensitive. It would be fun to hack into this and try clocking it off 
the OCXO, but I'm not there yet! :)


One interesting way would be to use the disciplined OCXO output to 
drive a DDS synthesizer set to the GPS unit's clock frequency (which, 
I'm assuming, is not the same as the OCXO frequency).  This approach 
has a number of potentially large problems (delay, spurs, DDS 
resolution, to name just 3), so I'm doubtful that it would work well 
-- but I do think it's worth trying, just because it's so simple and 
cheap ($3.85 ebay DDS board) and potentially instructive.


I might try some good old 'overkill' and put the GPS in it's own 
heavy aluminum box. It's been a thought for a while, and should 
address the thermal integration and time constants you referred to.


Insulate the GPS card from the box (use nylon or teflon standoffs 
with no through metal screws), and insulate the box from anything 
solid (same way); i.e., only air can change the box temperature, and 
only air can change the GPS card temperature.  Signals and power 
should go through bulkhead connectors and feedthrough caps on the box 
walls, with pigtails to get from there to the GPS card.  You 
probably don't need anything too massive, just whatever cast Hammond 
box it will fit in (allow for the connectors and feedthrough 
caps!!).  You can always add mass later (bolt slabs of aluminum to 
the outside of the box) -- but in this application, you shouldn't need to.


Best regards,

Charles



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[time-nuts] Frequency doubler with quadrature hybrid

Some time ago, I said I'd post a description and schematic of an 
excellent frequency doubler using a quadrature hybrid directional 
coupler to drive a diode DBM.  It is now available on ko4bb.com 
following Didier's recent work on the site (Thank you, Didier, for 
this wonderful resource):


http://www.ko4bb.com/manuals/download.php?file=05_GPS_Timing/4_App_Notes_and_Articles/Frequency_doubler_quadrature_DBM.pdf

When carefully constructed, this circuit has exceptional inherent 
balance and, consequently, very low feedthrough of the input 
frequency and its harmonics.  It also avoids most of the flicker 
noise created by push-push doublers.  For many uses, no output 
filtering is needed.  (The schematic includes a filter/amplifier, in 
case one needs a signal with even lower harmonics.)


In addition to the frequency doubler (which is drawn for 5MHz/10MHz, 
but can be easily scaled), I included the seminal article on 
lumped-constant quadrature hybrid splitter/combiners.  More 
information on these extremely useful but relatively unknown devices 
can be found in Chapters 3 and 9 of Wes Hayward's Experimental 
Methods in RF Design, in the discussions of single sideband and 
image-reject mixers.


(EMRFD is a must-have book for anyone playing with RF hardware, IMO, 
the same way Horowitz  Hill's The Art of Electronics is for 
general electronics knowledge.  Hayward's Introduction to Radio 
Frequency Design is also extremely useful.)


Best regards,

Charles


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Re: [time-nuts] Connections for FE-5680A rubidium sources

2014-12-16 Thread Clint Turner


Hello,

I've mounted both my LPRO-101 and FE-5680 in Hammond 1590-type cast 
aluminum boxes, bolting the rubidium unit to the lid of said box, and 
found the heat sinking of the entire arrangement to be entirely 
adequate.  In each case there is a (well filtered!) switching regulator 
present that contributes little to the overall thermal load as well as 
allowing them to run directly from a standard 12 volt equipment bus.


If you run the units at their minimum allowed voltage (19 volts for the 
LPRO-101, 15 volts for the FE-5680, IIRC) they will dissipate much less 
power as the regulators contained therein are linear type.  It struck me 
that at the lower limit voltages that they take slightly longer to warm 
up and come online, but still somewhere around the 3 minute mark for a 
Physics Lock.


Details may be found at:

http://www.ka7oei.com/10meg_rubidium1.html   - For the LPRO

http://www.ka7oei.com/10_MHz_Rubidium_FE-5680A.html  - For the '5680, of 
course!


73,

Clint
KA7OEI



On 16  December 2014 at 12:16, Bob Campkb...@n1k.org  wrote:

  Hi

One fairly important issue - the unit needs to be on a heat  sink. If you

run it without cooling of some sort, it will not run for very  many years.

Bob

I do realize that, but how big?  Normally the bigger the better is
not an unreasonable rule on heatsinks,  but I have heard that cooling
these too much is bad. I have here a heatsink  about 600 x 300 x 150
mm, although I think that is a bit OTT  !!

Dave


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[time-nuts] Simple AC mains zero-cross detector

Every so often, the subject of logging the zero-crossings of the AC 
mains comes up.  There are any number of ways to couple the AC mains 
to logic circuitry (coupling with very high value resistors, 
capacitor coupling, and optical isolation have been mentioned).  A 
simple AC mains ZCD that is transformer isolated and gives excellent 
results, is posted at ko4bb.com:


http://www.ko4bb.com/manuals/download.php?file=05_GPS_Timing/Simple_AC_Mains_Zero_Crossing_Detector.pdf

The ZCD uses a small, dual-primary power transformer, two 
transistors, and a few diodes, resistors, and capacitors.  It 
produces a ~100uS logic-level pulse at every positive zero-cross, the 
leading edge of which is predictably and stably related to the AC 
mains zero-cross.


Best regards,

Charles


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Re: [time-nuts] Connections for FE-5680A rubidium sources

2014-12-16 Thread billriches

Hi Dave,

The ones I have use the following pin out   

1 - 15 v
2 - ground
4 - 5 v
5 - ground
7 - 10 mhz

The pot on the side does nothing.

Look in the archives for my and other folks addition of an adjustment pot.
You can also adjust fx via software.  Pot is easier.

73,

Bill

I have a couple of Rb sources bought from China or Hong Kong a year or two
ago. I'd like to fix these up. Initially in a box where I can adjust them to
frequency manually, but perhaps later lock them to GPS.
Looking around the web, there are countless options on these things, and
different connection diagrams. Can anyone tell me what these are.
I have attached a picture of one. I have doctored the picture ab bit so
there are large arears of one shade, so the images compress quite a bit.
Essentially they are rather dirty looking metal boxes with rather dirty
white labels on, but such detail is not needed.

The big label says:

FE-5680A
FEI P/N 217400-303520-1

The smaller label with the barcode differs a bit between the two units.

1)  FE-5680A UN 61391 S/N 02444-57246 (on the one I photographed)
2)  FE-??80A UN 66794 S/N 0340-66253 (can't quite read all of it, but I
assume the missing characters are 56.

There is a small adjustment screw on the right, and a 9-pin D-connector,
with the lead cut at about 40 mm from the connector.

I can open one up and take a picture internally if need be.

Dave


---
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Re: [time-nuts] Connections for FE-5680A rubidium sources

2014-12-16 Thread Ryan Stasel

All,

It's interesting, but I've actually found the FE-5680 I have will power up, and
lock, from just 12v. Sure, takes a bit longer, but it eliminates the need for
the 7812 in the box, etc. I know the 5680 FAQ on ko4bb
(http://ko4bb.com/dokuwiki/doku.php?id=precision_timing:fe5680a_faq#input_voltage_requirements_spec_is_15_-_18_volts_dc_and_5v_dc)
states they'll run as low as 9.96v, but I've always been curious if that was
AFTER the 15v lock, or from cold.

Anyway, YMMV on any particular unit, but it would be interesting to hear if
anyone else is just powering them from a standard (linear) 12v wall wart, or
are you all just using 15v?

-Ryan Stasel

On Dec 16, 2014, at 09:54 , Clint Turner tur...@ussc.com wrote:

Hello,

I've mounted both my LPRO-101 and FE-5680 in Hammond 1590-type cast aluminum
boxes, bolting the rubidium unit to the lid of said box, and found the heat
sinking of the entire arrangement to be entirely adequate. In each case
there is a (well filtered!) switching regulator present that contributes
little to the overall thermal load as well as allowing them to run directly
from a standard 12 volt equipment bus.

If you run the units at their minimum allowed voltage (19 volts for the
LPRO-101, 15 volts for the FE-5680, IIRC) they will dissipate much less power
as the regulators contained therein are linear type. It struck me that at
the lower limit voltages that they take slightly longer to warm up and come
online, but still somewhere around the 3 minute mark for a Physics Lock.

Details may be found at:

http://www.ka7oei.com/10meg_rubidium1.html - For the LPRO

http://www.ka7oei.com/10_MHz_Rubidium_FE-5680A.html - For the '5680, of
course!

73,

Clint
KA7OEI

On 16 December 2014 at 12:16, Bob Campkb...@n1k.org wrote:
Hi

One fairly important issue - the unit needs to be on a heat sink. If you
run it without cooling of some sort, it will not run for very many years.
Bob
I do realize that, but how big? Normally the bigger the better is
not an unreasonable rule on heatsinks, but I have heard that cooling
these too much is bad. I have here a heatsink about 600 x 300 x 150
mm, although I think that is a bit OTT !!

Dave

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[time-nuts] (UK) FS: HP Agilent 53131A

2014-12-16 Thread Adrian Godwin

Due to a bulk purchase, I have two used 53131A counters to sell.
Preferably a UK buyer, looking for about £200 + postage. Standard
reference (not medium or high stability), calibration expired.

Please contact me off-list for full details.

-adrian
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[time-nuts] Fwd: CGSIC: FW: New NANU 2014090


Fellow time-nuts,

We have now 15 L2C signals and 8 L5 signals in the air.

An L2C only receiver start to become useful in it's own right.

L1 C/A, L2C and L5 would allow for tripple frequency receiver. Things is 
starting to be interesting, if you have the receiver for it. With a 
double-frequency receiver, the ionospheric errors could be significantly 
reduced. Better position and better time-stability.


Cheers,
Magnus

 Forwarded Message 
Subject: CGSIC: FW: New NANU 2014090
Date: Mon, 15 Dec 2014 14:16:29 +
From: Civil Global Positioning System Service Interface Committee 
(CGSIC) cg...@cgls.uscg.mil

Reply-To: cg...@cgls.uscg.mil
To: cg...@cgls.uscg.mil cg...@cgls.uscg.mil

All CGSIC:
The eighth GPS-IIF satellite, SVN-69/PRN-03, launched on 29 October 
2014, has completed its operational checkout and was set to healthy and 
usable Friday, December 12, 2014. See NANU 2014090 below.  This brings 
the number of satellites transmitting the L2C signal to 15 and those 
transmitting the L5 signal to 08.  The next GPS-IIF satellite, 
IIF-9/SVN-70 is tentatively scheduled for launch in March of 2015.

V/R
Rick Hamilton
CGSIC Executive Secretariat
GPS Information Analysis Team Lead
USCG Navigation Center
703-313-5930

=
-Original Message-
From: NANU [mailto:nanu-boun...@cgls.uscg.mil] On Behalf Of TIS-PF-NISWS
Sent: Friday, December 12, 2014 5:17 PM
To: NANU list server
Subject: New NANU 2014090

NOTICE ADVISORY TO NAVSTAR USERS (NANU) 2014090
SUBJ: SVN69 (PRN03) USABLE JDAY 346/2119
1. NANU TYPE: USABINIT
   NANU NUMBER: 2014090
   NANU DTG: 122108Z DEC 2014
   REFERENCE NANU: N/A
   REF NANU DTG: N/A
   SVN: 69
   PRN: 03
   START JDAY: 346
   START TIME ZULU: 2119
   START CALENDAR DATE: 12 DEC 2014
   STOP JDAY: N/A
   STOP TIME ZULU: N/A
   STOP CALENDAR DATE: N/A

2.  CONDITION: GPS SATELLITE SVN69 (PRN03) WAS USABLE AS OF JDAY 346
(12 DEC 2014) BEGINNING 2119 ZULU.

3.  POC: CIVILIAN - NAVCEN AT 703-313-5900, HTTP://WWW.NAVCEN.USCG.GOV
MILITARY - GPS OPERATIONS CENTER at HTTPS://GPS.AFSPC.AF.MIL/GPSOC, 
DSN 560-2541,
COMM 719-567-2541, gpsoperationscen...@us.af.mil, 
HTTPS://GPS.AFSPC.AF.MIL

MILITARY ALTERNATE - JOINT SPACE OPERATIONS CENTER, DSN 276-3514,
COMM 805-606-3514, jspoccombat...@vandenberg.af.mil

To unsubscribe, visit: 
http://www.navcen.uscg.gov/?pageName=listserverunsubscribesrvr=Nanu

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Re: [time-nuts] Documents relevant to SR620

2014-12-16 Thread Didier Juges

Apologies to Jean Louis, I obviously missed that part... :)

On Wed, Dec 10, 2014 at 3:47 PM, Jean-Louis Oneto jl.on...@free.fr wrote:

 I just uploaded the file to K04BB. com.
 Best regards,
 Jean-Louis


 On 10/12/2014 19:10, Charles Steinmetz wrote:

 Jeaen-Luis wrote:

  The size of the file is around 5.5 MB.
 Let me know if you are interested, and how I can send it to you.


 You can post it to k04bb.com:

 http://168.144.151.127/manuals/69.143.130.128/1_Upload_Instructions.php

 Best regards,

 Charles



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 --
 Jean-Louis Oneto
 email: jl.on...@free.fr


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Re: [time-nuts] Fwd: CGSIC: FW: New NANU 2014090

2014-12-16 Thread paul swed

Magnus exciting. Now which ublox receiver is that on ebay? :-)
Regards
Paul
WB8TSL

On Tue, Dec 16, 2014 at 4:09 PM, Magnus Danielson 
mag...@rubidium.dyndns.org wrote:

 Fellow time-nuts,

 We have now 15 L2C signals and 8 L5 signals in the air.

 An L2C only receiver start to become useful in it's own right.

 L1 C/A, L2C and L5 would allow for tripple frequency receiver. Things is
 starting to be interesting, if you have the receiver for it. With a
 double-frequency receiver, the ionospheric errors could be significantly
 reduced. Better position and better time-stability.

 Cheers,
 Magnus

  Forwarded Message 
 Subject: CGSIC: FW: New NANU 2014090
 Date: Mon, 15 Dec 2014 14:16:29 +
 From: Civil Global Positioning System Service Interface Committee (CGSIC) 
 cg...@cgls.uscg.mil
 Reply-To: cg...@cgls.uscg.mil
 To: cg...@cgls.uscg.mil cg...@cgls.uscg.mil

 All CGSIC:
 The eighth GPS-IIF satellite, SVN-69/PRN-03, launched on 29 October
 2014, has completed its operational checkout and was set to healthy and
 usable Friday, December 12, 2014. See NANU 2014090 below.  This brings the
 number of satellites transmitting the L2C signal to 15 and those
 transmitting the L5 signal to 08.  The next GPS-IIF satellite, IIF-9/SVN-70
 is tentatively scheduled for launch in March of 2015.
 V/R
 Rick Hamilton
 CGSIC Executive Secretariat
 GPS Information Analysis Team Lead
 USCG Navigation Center
 703-313-5930

 
 =
 -Original Message-
 From: NANU [mailto:nanu-boun...@cgls.uscg.mil] On Behalf Of TIS-PF-NISWS
 Sent: Friday, December 12, 2014 5:17 PM
 To: NANU list server
 Subject: New NANU 2014090

 NOTICE ADVISORY TO NAVSTAR USERS (NANU) 2014090
 SUBJ: SVN69 (PRN03) USABLE JDAY 346/2119
 1. NANU TYPE: USABINIT
NANU NUMBER: 2014090
NANU DTG: 122108Z DEC 2014
REFERENCE NANU: N/A
REF NANU DTG: N/A
SVN: 69
PRN: 03
START JDAY: 346
START TIME ZULU: 2119
START CALENDAR DATE: 12 DEC 2014
STOP JDAY: N/A
STOP TIME ZULU: N/A
STOP CALENDAR DATE: N/A

 2.  CONDITION: GPS SATELLITE SVN69 (PRN03) WAS USABLE AS OF JDAY 346
 (12 DEC 2014) BEGINNING 2119 ZULU.

 3.  POC: CIVILIAN - NAVCEN AT 703-313-5900, HTTP://WWW.NAVCEN.USCG.GOV
 MILITARY - GPS OPERATIONS CENTER at HTTPS://GPS.AFSPC.AF.MIL/GPSOC,
 DSN 560-2541,
 COMM 719-567-2541, gpsoperationscen...@us.af.mil,
 HTTPS://GPS.AFSPC.AF.MIL
 MILITARY ALTERNATE - JOINT SPACE OPERATIONS CENTER, DSN 276-3514,
 COMM 805-606-3514, jspoccombat...@vandenberg.af.mil

 To unsubscribe, visit: http://www.navcen.uscg.gov/?pageName=
 listserverunsubscribesrvr=Nanu
 ___
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 If you would like to report abuse of the CGLS listserv please send an
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Re: [time-nuts] Connections for FE-5680A rubidium sources

2014-12-16 Thread Dr. David Kirkby (Kirkby Microwave Ltd)

Hi

What ever you do, take the extra step of checking the baseplate temperature 
once you have things up and running. The Rb’s will *work* over a wide 
temperature range. The region over which they will last a long time is a bit 
more narrow. I seem to have spent a lot of time demonstrating that. Keeping the 
baseplate below 40C (and above 10) does indeed extend their lifespan. 

Bob

 On Dec 16, 2014, at 12:54 PM, Clint Turner tur...@ussc.com wrote:
 
 Hello,
 
 I've mounted both my LPRO-101 and FE-5680 in Hammond 1590-type cast aluminum 
 boxes, bolting the rubidium unit to the lid of said box, and found the heat 
 sinking of the entire arrangement to be entirely adequate.  In each case 
 there is a (well filtered!) switching regulator present that contributes 
 little to the overall thermal load as well as allowing them to run directly 
 from a standard 12 volt equipment bus.
 
 If you run the units at their minimum allowed voltage (19 volts for the 
 LPRO-101, 15 volts for the FE-5680, IIRC) they will dissipate much less power 
 as the regulators contained therein are linear type.  It struck me that at 
 the lower limit voltages that they take slightly longer to warm up and come 
 online, but still somewhere around the 3 minute mark for a Physics Lock.
 
 Details may be found at:
 
 http://www.ka7oei.com/10meg_rubidium1.html   - For the LPRO
 
 http://www.ka7oei.com/10_MHz_Rubidium_FE-5680A.html  - For the '5680, of 
 course!
 
 73,
 
 Clint
 KA7OEI
 
 
 On 16  December 2014 at 12:16, Bob Campkb...@n1k.org  wrote:
  Hi
 
 One fairly important issue - the unit needs to be on a heat  sink. If you
 run it without cooling of some sort, it will not run for very  many years.
 Bob
 I do realize that, but how big?  Normally the bigger the better is
 not an unreasonable rule on heatsinks,  but I have heard that cooling
 these too much is bad. I have here a heatsink  about 600 x 300 x 150
 mm, although I think that is a bit OTT  !!
 
 Dave
 
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Re: [time-nuts] Connections for FE-5680A rubidium sources

On 16 Dec 2014 23:06, Bob Camp kb...@n1k.org wrote:

 Hi

 What ever you do, take the extra step of checking the baseplate
temperature once you have things up and running. The Rb’s will *work* over
a wide temperature range. The region over which they will last a long time
is a bit more narrow. I seem to have spent a lot of time demonstrating
that. Keeping the baseplate below 40C (and above 10) does indeed extend
their lifespan.

 Bob

Cheers Bob.

I have a 2U 19 HP case that was used for a test set for a VNA. I will see
what the temperature is with that.

But the first thing is to test if they work.

Dave
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Re: [time-nuts] Fwd: CGSIC: FW: New NANU 2014090


Paul,

That is indeed the question. Considering that the signal is better 
supported, I hope the light goes on somewhere. The signals is all
1,023 Mchips/s, just a thad different. Should be possible to pull off if 
people want to do dual frequency without going full bandwidth.


Then again, if you are willing to pay good money, you can get it today.

Cheers,
Magnus

On 12/16/2014 11:41 PM, paul swed wrote:

Magnus exciting. Now which ublox receiver is that on ebay? :-)
Regards
Paul
WB8TSL

On Tue, Dec 16, 2014 at 4:09 PM, Magnus Danielson 
mag...@rubidium.dyndns.org wrote:


Fellow time-nuts,

We have now 15 L2C signals and 8 L5 signals in the air.

An L2C only receiver start to become useful in it's own right.

L1 C/A, L2C and L5 would allow for tripple frequency receiver. Things is
starting to be interesting, if you have the receiver for it. With a
double-frequency receiver, the ionospheric errors could be significantly
reduced. Better position and better time-stability.

Cheers,
Magnus

 Forwarded Message 
Subject: CGSIC: FW: New NANU 2014090
Date: Mon, 15 Dec 2014 14:16:29 +
From: Civil Global Positioning System Service Interface Committee (CGSIC) 
cg...@cgls.uscg.mil
Reply-To: cg...@cgls.uscg.mil
To: cg...@cgls.uscg.mil cg...@cgls.uscg.mil

All CGSIC:
 The eighth GPS-IIF satellite, SVN-69/PRN-03, launched on 29 October
2014, has completed its operational checkout and was set to healthy and
usable Friday, December 12, 2014. See NANU 2014090 below.  This brings the
number of satellites transmitting the L2C signal to 15 and those
transmitting the L5 signal to 08.  The next GPS-IIF satellite, IIF-9/SVN-70
is tentatively scheduled for launch in March of 2015.
V/R
Rick Hamilton
CGSIC Executive Secretariat
GPS Information Analysis Team Lead
USCG Navigation Center
703-313-5930


=
-Original Message-
From: NANU [mailto:nanu-boun...@cgls.uscg.mil] On Behalf Of TIS-PF-NISWS
Sent: Friday, December 12, 2014 5:17 PM
To: NANU list server
Subject: New NANU 2014090

NOTICE ADVISORY TO NAVSTAR USERS (NANU) 2014090
SUBJ: SVN69 (PRN03) USABLE JDAY 346/2119
1. NANU TYPE: USABINIT
NANU NUMBER: 2014090
NANU DTG: 122108Z DEC 2014
REFERENCE NANU: N/A
REF NANU DTG: N/A
SVN: 69
PRN: 03
START JDAY: 346
START TIME ZULU: 2119
START CALENDAR DATE: 12 DEC 2014
STOP JDAY: N/A
STOP TIME ZULU: N/A
STOP CALENDAR DATE: N/A

2.  CONDITION: GPS SATELLITE SVN69 (PRN03) WAS USABLE AS OF JDAY 346
 (12 DEC 2014) BEGINNING 2119 ZULU.

3.  POC: CIVILIAN - NAVCEN AT 703-313-5900, HTTP://WWW.NAVCEN.USCG.GOV
 MILITARY - GPS OPERATIONS CENTER at HTTPS://GPS.AFSPC.AF.MIL/GPSOC,
DSN 560-2541,
 COMM 719-567-2541, gpsoperationscen...@us.af.mil,
HTTPS://GPS.AFSPC.AF.MIL
 MILITARY ALTERNATE - JOINT SPACE OPERATIONS CENTER, DSN 276-3514,
 COMM 805-606-3514, jspoccombat...@vandenberg.af.mil

To unsubscribe, visit: http://www.navcen.uscg.gov/?pageName=
listserverunsubscribesrvr=Nanu
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Re: [time-nuts] Fwd: CGSIC: FW: New NANU 2014090


On 12/16/14, 3:36 PM, Magnus Danielson wrote:

Paul,

That is indeed the question. Considering that the signal is better
supported, I hope the light goes on somewhere. The signals is all
1,023 Mchips/s, just a thad different. Should be possible to pull off if
people want to do dual frequency without going full bandwidth.

Then again, if you are willing to pay good money, you can get it today.



what about one of the software receivers? I would think that making  L2 
and L5 filters isn't that tough, so all you need is the back end.




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Re: [time-nuts] CGSIC: FW: New NANU 2014090

Hi

 On Dec 16, 2014, at 7:01 PM, Jim Lux jim...@earthlink.net wrote:
 
 On 12/16/14, 3:36 PM, Magnus Danielson wrote:
 Paul,
 
 That is indeed the question. Considering that the signal is better
 supported, I hope the light goes on somewhere. The signals is all
 1,023 Mchips/s, just a thad different. Should be possible to pull off if
 people want to do dual frequency without going full bandwidth.
 
 Then again, if you are willing to pay good money, you can get it today.
 
 
 what about one of the software receivers? I would think that making  L2 and 
 L5 filters isn't that tough, so all you need is the back end.

….. and the back end is where all the work is. 

Bob

 
 
 
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Re: [time-nuts] CGSIC: FW: New NANU 2014090


Jim, Bob,

On 12/17/2014 01:06 AM, Bob Camp wrote:

Hi


On Dec 16, 2014, at 7:01 PM, Jim Lux jim...@earthlink.net wrote:

On 12/16/14, 3:36 PM, Magnus Danielson wrote:

Paul,

That is indeed the question. Considering that the signal is better
supported, I hope the light goes on somewhere. The signals is all
1,023 Mchips/s, just a thad different. Should be possible to pull off if
people want to do dual frequency without going full bandwidth.

Then again, if you are willing to pay good money, you can get it today.



what about one of the software receivers? I would think that making  L2 and L5 
filters isn't that tough, so all you need is the back end.


….. and the back end is where all the work is.


There is a fair amount of work along the full path.

LNA with some L2 and L5 filters is pretty easy.

I think you still want to have a correlator baseband processing in say 
an FPGA.


There is naturally stuff to be done on the L2C and L5 modulated signals, 
but it goes in a relatively slow paze so that even modest processors can 
keep up with it.


Cheers,
Magnus
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Re: [time-nuts] CGSIC: FW: New NANU 2014090


On 12/16/14, 4:06 PM, Bob Camp wrote:

Hi


On Dec 16, 2014, at 7:01 PM, Jim Lux jim...@earthlink.net wrote:

On 12/16/14, 3:36 PM, Magnus Danielson wrote:

Paul,

That is indeed the question. Considering that the signal is better
supported, I hope the light goes on somewhere. The signals is all
1,023 Mchips/s, just a thad different. Should be possible to pull off if
people want to do dual frequency without going full bandwidth.

Then again, if you are willing to pay good money, you can get it today.



what about one of the software receivers? I would think that making  L2 and L5 
filters isn't that tough, so all you need is the back end.


….. and the back end is where all the work is.



but there probably are some software receivers (open source?) out there..

http://gps.psas.pdx.edu/ appears to have stalled for lack of hardware

http://gnss-sdr.org/
This article provides details about the support that GNSS-SDR offers 
for real-time operation using the GNSS USB front-end SiGe GN3S Sampler 
v2. Unfortunately, this product has been retired and replaced by a newer 
version v3, but we hope this still can be useful to v2 users. 


The RTL dongle might a choice, but the Elonics E4000 flavor has a whole 
from 1100-1250, and since L2 is at 1227, that's a problem.


http://www.taroz.net/gnsssdrlib_e.html
appears to support all the frequencies and modulations

the GN3S sampler is available from SparkFun for $500.. if they have them 
in stock. I'm not sure it can tune the band, though: they don't seem to 
have a block diagram and I'm not going to read the source code to 
figure it out.  Seems from the SiGe datasheet that it's L1 only, but the 
well equipped timenut might be able to fake the reference crystal to one 
that would tune L2 and L5.


http://www.nsl.eu.com/primo.html seems to be hardware that can do all 
the stuff..  Maybe GBP800? in a nice box.




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Re: [time-nuts] CGSIC: FW: New NANU 2014090


On 12/16/14, 4:29 PM, Magnus Danielson wrote:

Jim, Bob,

On 12/17/2014 01:06 AM, Bob Camp wrote:

Hi


On Dec 16, 2014, at 7:01 PM, Jim Lux jim...@earthlink.net wrote:

On 12/16/14, 3:36 PM, Magnus Danielson wrote:

Paul,

That is indeed the question. Considering that the signal is better
supported, I hope the light goes on somewhere. The signals is all
1,023 Mchips/s, just a thad different. Should be possible to pull
off if
people want to do dual frequency without going full bandwidth.

Then again, if you are willing to pay good money, you can get it today.



what about one of the software receivers? I would think that making
L2 and L5 filters isn't that tough, so all you need is the back end.


….. and the back end is where all the work is.


There is a fair amount of work along the full path.

LNA with some L2 and L5 filters is pretty easy.

I think you still want to have a correlator baseband processing in say
an FPGA.



well, yes.. but I don't know if there's any handy open source free cores 
out there for that.


 I do know grin of an implementation that does the acq and track in a 
pair of Xilinx 2-3000 parts and does the nav solution in a SPARC V8, but 
it's not open source and it's definitely export controlled.


Seems that what's out there is mostly record bits and postprocess in 
C++ or Matlab Several textbooks even include it.






There is naturally stuff to be done on the L2C and L5 modulated signals,
but it goes in a relatively slow paze so that even modest processors can
keep up with it.


Indeed.. we do 24 channels (where channel is one PRN at one frequency) 
with a 3 frequency solution without making a 66 MHz LEON2 based SPARC 
sweat too much.



That's why it would be intriguing if someone had the FPGA stuff out there.

It would still be an expensive project, I suspect.  Either you'd have a 
few $50-100 boards that would need interfacing and a lot of time, or a 
$1000 board with less time.



One hopes that in a few years, multifrequency stuff will become available.
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Re: [time-nuts] CGSIC: FW: New NANU 2014090

Hi


 On Dec 16, 2014, at 7:29 PM, Magnus Danielson mag...@rubidium.dyndns.org 
 wrote:
 
 Jim, Bob,
 
 On 12/17/2014 01:06 AM, Bob Camp wrote:
 Hi
 
 On Dec 16, 2014, at 7:01 PM, Jim Lux jim...@earthlink.net wrote:
 
 On 12/16/14, 3:36 PM, Magnus Danielson wrote:
 Paul,
 
 That is indeed the question. Considering that the signal is better
 supported, I hope the light goes on somewhere. The signals is all
 1,023 Mchips/s, just a thad different. Should be possible to pull off if
 people want to do dual frequency without going full bandwidth.
 
 Then again, if you are willing to pay good money, you can get it today.
 
 
 what about one of the software receivers? I would think that making  L2 and 
 L5 filters isn't that tough, so all you need is the back end.
 
 ….. and the back end is where all the work is.
 
 There is a fair amount of work along the full path.
 
 LNA with some L2 and L5 filters is pretty easy.
 
 I think you still want to have a correlator baseband processing in say an 
 FPGA.
 
 There is naturally stuff to be done on the L2C and L5 modulated signals, but 
 it goes in a relatively slow paze so that even modest processors can keep up 
 with it.

Since these are “odd” signals, the hardware is only a small part of the 
problem. I would bet that the standard bits and pieces are only going to get 
you part of the way with these signals. The 10% hardware hours / 90% software 
hours likely applies here. 

Bob


 
 Cheers,
 Magnus
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Re: [time-nuts] CGSIC: FW: New NANU 2014090


Jim,

On 12/17/2014 01:46 AM, Jim Lux wrote:

On 12/16/14, 4:29 PM, Magnus Danielson wrote:

Jim, Bob,


There is a fair amount of work along the full path.

LNA with some L2 and L5 filters is pretty easy.

I think you still want to have a correlator baseband processing in say
an FPGA.



well, yes.. but I don't know if there's any handy open source free cores
out there for that.

  I do know grin of an implementation that does the acq and track in a
pair of Xilinx 2-3000 parts and does the nav solution in a SPARC V8, but
it's not open source and it's definitely export controlled.


For that application it needs to break both the limits at the same time, 
for sure.



Seems that what's out there is mostly record bits and postprocess in
C++ or Matlab Several textbooks even include it.


It's good for many purposes as you get yourself up to speed.


There is naturally stuff to be done on the L2C and L5 modulated signals,
but it goes in a relatively slow paze so that even modest processors can
keep up with it.


Indeed.. we do 24 channels (where channel is one PRN at one frequency)
with a 3 frequency solution without making a 66 MHz LEON2 based SPARC
sweat too much.


That's why it would be intriguing if someone had the FPGA stuff out there.


Indeed. I did a GPS correlator core once, but it had issues to fit the 
FPGA I had at hand at the time. The software receiver I did was not at 
all doing real-time, but it did do many of the crucial points and was a 
nice exercise.



It would still be an expensive project, I suspect.  Either you'd have a
few $50-100 boards that would need interfacing and a lot of time, or a
$1000 board with less time.


One hopes that in a few years, multifrequency stuff will become available.


Indeed. Maybe a complete implementation just needs to hit the web..

Cheers,
Magnus
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Re: [time-nuts] CGSIC: FW: New NANU 2014090

2014-12-16 Thread Henry Hallam

The Swift Navigation Piksi project may be of interest:

http://swiftnav.com/piksi.html

It has an FPGA for correlation with an ARM Cortex-M3 for tracking
loops and navigation.  The hardware and ARM firmware is open source,
but the FPGA design is closed-source at the moment.  However, I don't
see why the FPGA would need adapting for use with L2C  L5.

I know the Swift Nav folks are looking into a multi-frequency product.
One of the main obstacles is a commodity front-end solution, and
antennas at reasonable prices.

Henry

On Tue, Dec 16, 2014 at 5:01 PM, Magnus Danielson
mag...@rubidium.dyndns.org wrote:
 Jim,

 On 12/17/2014 01:46 AM, Jim Lux wrote:

 On 12/16/14, 4:29 PM, Magnus Danielson wrote:

 Jim, Bob,


 There is a fair amount of work along the full path.

 LNA with some L2 and L5 filters is pretty easy.

 I think you still want to have a correlator baseband processing in say
 an FPGA.


 well, yes.. but I don't know if there's any handy open source free cores
 out there for that.

   I do know grin of an implementation that does the acq and track in a
 pair of Xilinx 2-3000 parts and does the nav solution in a SPARC V8, but
 it's not open source and it's definitely export controlled.


 For that application it needs to break both the limits at the same time, for
 sure.

 Seems that what's out there is mostly record bits and postprocess in
 C++ or Matlab Several textbooks even include it.


 It's good for many purposes as you get yourself up to speed.

 There is naturally stuff to be done on the L2C and L5 modulated signals,
 but it goes in a relatively slow paze so that even modest processors can
 keep up with it.


 Indeed.. we do 24 channels (where channel is one PRN at one frequency)
 with a 3 frequency solution without making a 66 MHz LEON2 based SPARC
 sweat too much.


 That's why it would be intriguing if someone had the FPGA stuff out there.


 Indeed. I did a GPS correlator core once, but it had issues to fit the FPGA
 I had at hand at the time. The software receiver I did was not at all doing
 real-time, but it did do many of the crucial points and was a nice exercise.

 It would still be an expensive project, I suspect.  Either you'd have a
 few $50-100 boards that would need interfacing and a lot of time, or a
 $1000 board with less time.


 One hopes that in a few years, multifrequency stuff will become available.


 Indeed. Maybe a complete implementation just needs to hit the web..

 Cheers,
 Magnus

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Re: [time-nuts] Connections for FE-5680A rubidium sources

2014-12-16 Thread Brian M

I just power mine off an old 19vdc laptop supply dropped with a linear
regulator (and filtered) to provide ~17vdc No 5vdc supply required for
mine. I recall reading that some have an internal 5v regulator. I believe
the way to check is if the lock pin signals and PPS is present without
external 5vdc supply. Mine does. Your experience might vary - but that was
my experience with my copy.

I also didn't have serial connected on mine. Had to mod it to bring out
serial. Anybody else face that?

- Brian

On Tuesday, December 16, 2014, Ryan Stasel rsta...@uoregon.edu wrote:

All,

It's interesting, but I've actually found the FE-5680 I have will power
up, and lock, from just 12v. Sure, takes a bit longer, but it eliminates
the need for the 7812 in the box, etc. I know the 5680 FAQ on ko4bb (
http://ko4bb.com/dokuwiki/doku.php?id=precision_timing:fe5680a_faq#input_voltage_requirements_spec_is_15_-_18_volts_dc_and_5v_dc)
states they'll run as low as 9.96v, but I've always been curious if that
was AFTER the 15v lock, or from cold.

Anyway, YMMV on any particular unit, but it would be interesting to hear
if anyone else is just powering them from a standard (linear) 12v wall
wart, or are you all just using 15v?

-Ryan Stasel

On Dec 16, 2014, at 09:54 , Clint Turner tur...@ussc.com javascript:;
wrote:

Hello,

I've mounted both my LPRO-101 and FE-5680 in Hammond 1590-type cast
aluminum boxes, bolting the rubidium unit to the lid of said box, and found
the heat sinking of the entire arrangement to be entirely adequate. In
each case there is a (well filtered!) switching regulator present that
contributes little to the overall thermal load as well as allowing them to
run directly from a standard 12 volt equipment bus.

If you run the units at their minimum allowed voltage (19 volts for the
LPRO-101, 15 volts for the FE-5680, IIRC) they will dissipate much less
power as the regulators contained therein are linear type. It struck me
that at the lower limit voltages that they take slightly longer to warm up
and come online, but still somewhere around the 3 minute mark for a
Physics Lock.

Details may be found at:

http://www.ka7oei.com/10meg_rubidium1.html - For the LPRO

http://www.ka7oei.com/10_MHz_Rubidium_FE-5680A.html - For the '5680,
of course!

73,

Clint
KA7OEI

On 16 December 2014 at 12:16, Bob Campkb...@n1k.org javascript:;
wrote:
Hi

One fairly important issue - the unit needs to be on a heat sink. If
you
run it without cooling of some sort, it will not run for very many
years.
Bob
I do realize that, but how big? Normally the bigger the better is
not an unreasonable rule on heatsinks, but I have heard that cooling
these too much is bad. I have here a heatsink about 600 x 300 x 150
mm, although I think that is a bit OTT !!

Dave

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Re: [time-nuts] Fwd: CGSIC: FW: New NANU 2014090

2014-12-16 Thread Gregory Maxwell

On Wed, Dec 17, 2014 at 12:01 AM, Jim Lux jim...@earthlink.net wrote:
 On 12/16/14, 3:36 PM, Magnus Danielson wrote:
 what about one of the software receivers? I would think that making  L2 and
 L5 filters isn't that tough, so all you need is the back end.

I'm pretty sure GNSS-SDRLIB supports L2C,  you can see it working with
a ~$400 bladerf

http://www.rtl-sdr.com/real-time-gps-positioning-bladerf/

Though getting dual band, in phase, requires something like a $1100
USRP B210... and that that point you're getting in to the price-points
where you can find surplus survey receivers and such.

From a timenuts perspective, it may be more interesting to go the SDR
route, since the survey receiver is not likely to have a lot of
affordances for timing applications and there is a lot of interesting
things you could do in software.

There have been some people talking about GNSS targeted SDRs, e.g.
things with 4x  in phase down mixers and backing ADCs that could
simultaneously capture every current/known GNSS signal and send them
down to the computer, at a reasonably low price... but I think none
have moved past the prototyping phase.

The nearest I'm aware that seems actually available is
http://www.onetalent-gnss.com/ideas/software-defined-radio/sdrnav40
but I don't really know anything about it. (e.g. if it's real, what
the software support story is, etc.)
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Re: [time-nuts] Fwd: CGSIC: FW: New NANU 2014090

HI

 On Dec 16, 2014, at 8:14 PM, Gregory Maxwell gmaxw...@gmail.com wrote:
 
 On Wed, Dec 17, 2014 at 12:01 AM, Jim Lux jim...@earthlink.net wrote:
 On 12/16/14, 3:36 PM, Magnus Danielson wrote:
 what about one of the software receivers? I would think that making  L2 and
 L5 filters isn't that tough, so all you need is the back end.
 
 I'm pretty sure GNSS-SDRLIB supports L2C,  you can see it working with
 a ~$400 bladerf
 
 http://www.rtl-sdr.com/real-time-gps-positioning-bladerf/
 
 Though getting dual band, in phase, requires something like a $1100
 USRP B210... and that that point you're getting in to the price-points
 where you can find surplus survey receivers and such.
 
 From a timenuts perspective, it may be more interesting to go the SDR
 route, since the survey receiver is not likely to have a lot of
 affordances for timing applications and there is a lot of interesting
 things you could do in software.

That qualifier is indeed something I should have stated earlier. My assumption 
is that a high quality timing receiver is the target. The whole fixed location 
/ single sat solution / per sat solution  stuff is what I’m thinking about.

No I didn’t mention that earlier … I should have.

Bob 

 
 There have been some people talking about GNSS targeted SDRs, e.g.
 things with 4x  in phase down mixers and backing ADCs that could
 simultaneously capture every current/known GNSS signal and send them
 down to the computer, at a reasonably low price... but I think none
 have moved past the prototyping phase.
 
 The nearest I'm aware that seems actually available is
 http://www.onetalent-gnss.com/ideas/software-defined-radio/sdrnav40
 but I don't really know anything about it. (e.g. if it's real, what
 the software support story is, etc.)
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Re: [time-nuts] Connections for FE-5680A rubidium sources

On Dec 16, 2014, at 4:36 PM, Brian M brayn...@gmail.com wrote:

I just power mine off an old 19vdc laptop supply dropped with a linear
regulator (and filtered) to provide ~17vdc

I think that keeping the internal regulators running is a good idea. The more
stages of stabilization and clean up, the better.

No 5vdc supply required for
mine. I recall reading that some have an internal 5v regulator. I believe
the way to check is if the lock pin signals and PPS is present without
external 5vdc supply. Mine does. Your experience might vary - but that was
my experience with my copy.

I also didn't have serial connected on mine. Had to mod it to bring out
serial. Anybody else face that?

From what I’ve seen, if there are 8 basic features on these Rb’s then there is
a unit out there with each of those features either present or absent. We only
have seen the most popular 32 out of the 256 that are running around.

Don’t bother to bug the manufacturer for info. They all appear to have been OEM
custom models. I’m amazed that they could find that many customers and slots
for them ….

Bob

- Brian

On Tuesday, December 16, 2014, Ryan Stasel rsta...@uoregon.edu wrote:

All,

It's interesting, but I've actually found the FE-5680 I have will power
up, and lock, from just 12v. Sure, takes a bit longer, but it eliminates
the need for the 7812 in the box, etc. I know the 5680 FAQ on ko4bb (
http://ko4bb.com/dokuwiki/doku.php?id=precision_timing:fe5680a_faq#input_voltage_requirements_spec_is_15_-_18_volts_dc_and_5v_dc)
states they'll run as low as 9.96v, but I've always been curious if that
was AFTER the 15v lock, or from cold.

Anyway, YMMV on any particular unit, but it would be interesting to hear
if anyone else is just powering them from a standard (linear) 12v wall
wart, or are you all just using 15v?

-Ryan Stasel

On Dec 16, 2014, at 09:54 , Clint Turner tur...@ussc.com javascript:;
wrote:

Hello,

I've mounted both my LPRO-101 and FE-5680 in Hammond 1590-type cast
aluminum boxes, bolting the rubidium unit to the lid of said box, and found
the heat sinking of the entire arrangement to be entirely adequate. In
each case there is a (well filtered!) switching regulator present that
contributes little to the overall thermal load as well as allowing them to
run directly from a standard 12 volt equipment bus.

If you run the units at their minimum allowed voltage (19 volts for the
LPRO-101, 15 volts for the FE-5680, IIRC) they will dissipate much less
power as the regulators contained therein are linear type. It struck me
that at the lower limit voltages that they take slightly longer to warm up
and come online, but still somewhere around the 3 minute mark for a
Physics Lock.

Details may be found at:

http://www.ka7oei.com/10meg_rubidium1.html - For the LPRO

http://www.ka7oei.com/10_MHz_Rubidium_FE-5680A.html - For the '5680,
of course!

73,

Clint
KA7OEI

On 16 December 2014 at 12:16, Bob Campkb...@n1k.org javascript:;
wrote:
Hi

One fairly important issue - the unit needs to be on a heat sink. If
you
run it without cooling of some sort, it will not run for very many
years.
Bob
I do realize that, but how big? Normally the bigger the better is
not an unreasonable rule on heatsinks, but I have heard that cooling
these too much is bad. I have here a heatsink about 600 x 300 x 150
mm, although I think that is a bit OTT !!

Dave

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Re: [time-nuts] Simple AC mains zero-cross detector

2014-12-16 Thread Dave M

Charles Steinmetz wrote:

Every so often, the subject of logging the zero-crossings of the AC
mains comes up. There are any number of ways to couple the AC mains
to logic circuitry (coupling with very high value resistors,
capacitor coupling, and optical isolation have been mentioned). A
simple AC mains ZCD that is transformer isolated and gives excellent
results, is posted at ko4bb.com:

http://www.ko4bb.com/manuals/download.php?file=05_GPS_Timing/Simple_AC_Mains_Zero_Crossing_Detector.pdf

The ZCD uses a small, dual-primary power transformer, two
transistors, and a few diodes, resistors, and capacitors. It
produces a ~100uS logic-level pulse at every positive zero-cross, the
leading edge of which is predictably and stably related to the AC
mains zero-cross.

Best regards,

Charles

I'm not trying to downplay the circuit in the link above, but I want to
offer another possible solution to Zero-Crossing needs.

Here's an Idea For Design from EDN magazine that I've used a couple times in
non-time-nut circuits, and I must say that it works beautifully. I have no
measurements that would satisfy a time-nut's curiosity, so if someone wants
to Spice it or otherwise tear it apart, please do..
My use for the circuit was in a spot welder control; the output was used to
sync and cycle a counter-driven trigger for an alternistor, all of which
controlled the number of power line cycles that the welder transformer
received for the weld. It worked well for me until I sold the whole
contraption. Don't know whatever happened to it after the guy moved away
from the area; never heard from him again. I hope it's still working.

http://electronicdesign.com/analog/differential-line-receivers-function-analog-zero-crossing-detectors

Dave M

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[time-nuts] Lady Heather and comm port setup...

2014-12-16 Thread Mark Sims

Since version 3.1 Lady Heather should be able to find a 9600,8,ODD,1 device.  
This  was added for the Resolution T timing receiver.   It may take it a minute 
or so for it to figure out.   If the program does not see a valid receiver 
version message within 30 seconds or so it toggles the parity setting and tries 
again.

Or you can try the /rt command line option.  This says to try ODD parity first. 
  
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Re: [time-nuts] Choke Rings and Points North

2014-12-16 Thread Dave M


Jim Lux wrote:

On 12/16/14, 5:59 AM, Tom Van Baak wrote:

Clever idea, but..

Most rotary joints have more phase and amplitude variability than
the antenna.

So you're stuck with rotating back and forth with a cable that's
flexing and now you get to measure the phase variability of the
coax.


I was thinking of some sort of non-contact RF bridge that would allow
either side to rotate independently. Converting to optical would make
this easy, but there must be a way to do it at 1.5 GHz too.



two nested coils forming an air core transformer or slip rings are the
typical approach.
(Waveguide at 1.5 GHz is somewhat unwieldy in size).

The trick is in holding mechanical tolerances tight enough.I guess,
1mm mechanical tolerance (easy, easy) would be comparable to the phase
center displacement.



You really need to have your entire GPS system antenna and receiver
on the rotating table (which will need to have temperature
controls, etc.)

Oh, what a pit one can descend into with the goal of reducing
everything to a minimum error.


In this case the goal is actually not minimizing error. The goal is
to vary each possible error source with its own prime modulation
period. Collect lots of data and the FFT tells you how much each
error contributes to the pie.


Yes, but how do you know whether it's coax flex or phase center
displacement that's causing your 17 hour periodicity.

I was thinking not so much reducing error in the overall measurement,
but in reducing the uncertainty in the estimate of the size of each
contributor to the overall system.




For example, instead of temperature control you modulate temperature
by 5C over a 13 hour period. Instead of voltage control you modulate
the 5V antenna power by 10% every 1.7 hours, etc.



Inquiring minds surely are in high gear!!  And to think, all I wanted to 
know was how close I needed to to point to north!!


LMAO!!

Dave M 



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Re: [time-nuts] Simple AC mains zero-cross detector

Indeed looking at the AC line is a Time Nut sort of thing to do. It was one of
the first things I did with an old Beckman counter back in the 1960’s. Yes I
realize that the AC line is a very noisy signal and that this may not be needed:

The same limiter / noise shaper stuff that works for a DMTD is equally at home
processing a 60 Hz sine wave. The rise time, bandwidth, and progressive stage
gain issues are the same. The Collins paper on hard limiters does indeed apply
here. You *could* make a 60 Hz chain that got down into 1 us sort of
resolution.

Again, just because you can does not mean you should.

Bob

On Dec 16, 2014, at 8:58 PM, Dave M dgmin...@mediacombb.net wrote:

Charles Steinmetz wrote:
Every so often, the subject of logging the zero-crossings of the AC
mains comes up. There are any number of ways to couple the AC mains
to logic circuitry (coupling with very high value resistors,
capacitor coupling, and optical isolation have been mentioned). A
simple AC mains ZCD that is transformer isolated and gives excellent
results, is posted at ko4bb.com:

http://www.ko4bb.com/manuals/download.php?file=05_GPS_Timing/Simple_AC_Mains_Zero_Crossing_Detector.pdf

Best regards,

Charles

I'm not trying to downplay the circuit in the link above, but I want to offer
another possible solution to Zero-Crossing needs.

http://electronicdesign.com/analog/differential-line-receivers-function-analog-zero-crossing-detectors

Dave M

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Re: [time-nuts] Choke Rings and Points North

Hi

 On Dec 16, 2014, at 9:15 PM, Dave M dgmin...@mediacombb.net wrote:
 
 Jim Lux wrote:
 On 12/16/14, 5:59 AM, Tom Van Baak wrote:
 Clever idea, but..
 
 Most rotary joints have more phase and amplitude variability than
 the antenna.
 
 So you're stuck with rotating back and forth with a cable that's
 flexing and now you get to measure the phase variability of the
 coax.
 
 I was thinking of some sort of non-contact RF bridge that would allow
 either side to rotate independently. Converting to optical would make
 this easy, but there must be a way to do it at 1.5 GHz too.
 
 
 two nested coils forming an air core transformer or slip rings are the
 typical approach.
 (Waveguide at 1.5 GHz is somewhat unwieldy in size).
 
 The trick is in holding mechanical tolerances tight enough.I guess,
 1mm mechanical tolerance (easy, easy) would be comparable to the phase
 center displacement.
 
 
 You really need to have your entire GPS system antenna and receiver
 on the rotating table (which will need to have temperature
 controls, etc.)
 
 Oh, what a pit one can descend into with the goal of reducing
 everything to a minimum error.
 
 In this case the goal is actually not minimizing error. The goal is
 to vary each possible error source with its own prime modulation
 period. Collect lots of data and the FFT tells you how much each
 error contributes to the pie.
 
 Yes, but how do you know whether it's coax flex or phase center
 displacement that's causing your 17 hour periodicity.
 
 I was thinking not so much reducing error in the overall measurement,
 but in reducing the uncertainty in the estimate of the size of each
 contributor to the overall system.
 
 
 
 For example, instead of temperature control you modulate temperature
 by 5C over a 13 hour period. Instead of voltage control you modulate
 the 5V antenna power by 10% every 1.7 hours, etc.
 
 
 Inquiring minds surely are in high gear!!  And to think, all I wanted to know 
 was how close I needed to to point to north!!

The need to point north is a legitimate question. There is a chance that they 
designed some magic into it to deliberately shape the response. 

Based on the analysis done so far, you have to wonder just how they set up to 
check these things for phase center. Given the money you pay for them, I would 
hope they have a definitive test. Getting back an answer like “some guy named 
Bob did some math” in response to a request for traceability would be a major 
downer ….

Bob

 
 LMAO!!
 
 Dave M 
 
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Re: [time-nuts] Choke Rings and Points North



Inquiring minds surely are in high gear!!  And to think, all I 
wanted to know was how close I needed to to point to north!!


The need to point north is a legitimate question. There is a chance 
that they designed some magic into it to deliberately shape the response.


Having taken a few apart, I very much doubt that.  I think they try 
to get the phase center coincident with the mechanical center, but 
knowing that it won't be exact, they want you to orient it so that 
the residual error is always in the same direction.  You can point 
the arrow in any direction you want, as long as you do it consistently.


Best regards,

Charles



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Re: [time-nuts] Set time on Solaris computer from HP 58503A

2014-12-16 Thread Neil Schroeder

Of *course* you can sync to better than a millisecond on the LAN.  There's
not a machine worldwide at my employer more than 600 micros off from each
other, and the machines at my house are within 50.

You wanna start talking the sync-e+1588 test I'm doing?  We're speaking in
nanos then.

My LTE Lite is the only USB pps I have presently - and it pulls my time
well over 200 milliseconds off reference.  That's a massive change from the
1 or less I am from the internet and the 50 micros from the other boxes.

NS

On Sun, Dec 14, 2014 at 10:30 AM, Chris Albertson albertson.ch...@gmail.com
 wrote:

 I would still like to experiment with it. As I wrote earlier I bought this
  for a frequency reference,  not a clock, but I would not object to a bit
 of
  fun messing around with it.
 
 
 If the goal is just getting good enough time onto the Solaris machine then
 use NTP and some pool servers on the Internet.  You get about 10
 millisecond level accuracy and the cost is zero.  If you have solaris
 running you might even have this all setup and running.  If not do this as
 the first step and verify it works.

 If 10ms is unacceptable, next step is to connect the PPS signal.  Doing
 this will move you from milli to micro second level accuracy.   It is easy
 if the Solaris machine has a real serial port.   If you have to go through
 a USB dongle you loose about an order of magnitude accuracy but this is
 still very good.

 There is zero point in buying a special computer to run NTP.  Just use any
 computer you own that is already running 24x7.  Of course if you don't have
 a computer that runs 24x7 then you would look for one that uses very little
 power.

 Don't worry to much if the USB connection skews the time on the NTP server
 by some tens of microseconds, your server can't transfer time to your other
 computers on the LAN any better than millisecond level so a few tenths of
 an millisecond hardly mater.

 My opinion of computer time is that for normal use being a few milliseconds
 off is OK because the typical monitor is refreshed no faster than 100Hz so
 you have lag cause by screen refresh times even if the internal clock is
 dead-on perfect.  Same for disk time stamps, these is lag in the IO system
 too


 --

 Chris Albertson
 Redondo Beach, California
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Re: [time-nuts] Simple AC mains zero-cross detector


Bob wrote:

The Collins paper on hard limiters does indeed apply here. You 
*could* make a 60 Hz chain that got down into  1 us sort of resolution.


I don't know how much less than 1uS you mean by , but I was 
seeing less than 1uS jitter with the circuit described.


Best regards,

Charles



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Re: [time-nuts] Lady Heather and comm port setup...

2014-12-16 Thread Chuck Harris


Thanks Mark!

I figured that there had to be a way, especially given that
Trimble's former TSIP standard was 9600,8,ODD,1.

Now, if I could figure out why LH thinks it needs something
newer than windows 95... which is what is on the old 486
laptop that I would like to use for that purpose...

-Chuck Harris

Mark Sims wrote:

Since version 3.1 Lady Heather should be able to find a 9600,8,ODD,1 device.  
This
was added for the Resolution T timing receiver.   It may take it a minute or so
for it to figure out.   If the program does not see a valid receiver version
message within 30 seconds or so it toggles the parity setting and tries again.

Or you can try the /rt command line option.  This says to try ODD parity first.
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Re: [time-nuts] Choke Rings and Points North

2014-12-16 Thread Chuck Harris


I would venture that the extent of the magic was to note the physical
center of the array, and call that the phase center.

As long as you always orient the antenna in the same direction, any
errors that might exist in the real phase center will be consistent,
and could be corrected for by noting the offset from a benchmark.

-Chuck Harris

Bob Camp wrote:


Inquiring minds surely are in high gear!!  And to think, all I wanted to know
was how close I needed to to point to north!!


The need to point north is a legitimate question. There is a chance that they
designed some magic into it to deliberately shape the response.

Based on the analysis done so far, you have to wonder just how they set up to
check these things for phase center. Given the money you pay for them, I would
hope they have a definitive test. Getting back an answer like “some guy named 
Bob
did some math” in response to a request for traceability would be a major downer
….

Bob



LMAO!!

Dave M

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Re: [time-nuts] Simple AC mains zero-cross detector