Re: [time-nuts] IEEE Spectrum - Dec 2017 - article on chip-scale atomic frequency reference

Citerar Mark Sims : In the standards definitions that include "at sea level", the question these days is "which sea level?". As ocean temperature changes sea level will change (except maybe in Washington DC). Will the standards be amended to include something like

Re: [time-nuts] Ships fooled in GPS spoofing attack suggest Russian cyberweapon

Hi Martin, No there was also a SDR hack to spoof. http://www.rtl-sdr.com/cheating-at-pokemon-go-with-a-hackrf-and-gps-spoofing/ --      Björn Sent from my smartphone. Original message From: Martin Burnicki Date: 14/08/2017 11:42 (GMT+01:00) To:

Re: [time-nuts] TU30 jump second

Hi Bob & Bo, This was discussed a long time ago on      http://www.gpskit.nl/forum/ which is defunced since many years. To measure the delay I suggest setting it up as a NMEA refclock to ntpd. But fudge it so that it is only collecting data to watch and log the offsets. IIRC delays for the

Re: [time-nuts] ADEV query Timelab and TICC

Look at ICD-GPS-060. 10V into 50ohm, sub 50ns risetime and 20us pulse lenght is specified in figure 3-2. --     Björn Sent from my smartphone. Original message From: Hal Murray Date: 21/03/2017 19:18 (GMT+01:00) To: Tom Van Baak

Re: [time-nuts] time/sampling behavior of RTL-SDR

Hi Jim, Did you look at the below article? http://www.rtl-sdr.com/a-multi-channel-coherent-rtl-sdr-product-for-passive-radardirection-finding-and-more/ --     Björn Sent from my smartphone. Original message From: jimlux Date: 07/03/2017 22:08 (GMT+01:00)

Re: [time-nuts] Temperature (environmental) sensors

I like the Bosch BME280 conneced to a Raspberry PI. https://learn.adafruit.com/adafruit-bme280-humidity-barometric-pressure-temperature-sensor-breakout/pinouts https://github.com/adafruit/Adafruit_Python_BME280/blob/master/README.md --   Björn Sent from my smartphone. Original message

Re: [time-nuts] TrueTime/Symmetricon XL-AK date reset failure

Hi Joe! The Gps receiver module inside the XL-AK could have been hit by the 1024 week problem. Do the XL box have a display showing date/year? What does that show? --    Björn Sent from my smartphone. Original message From: Joe Pendergrass Date: 02/01/2017

Re: [time-nuts] GALILEO online: any changes seen?

The key change is that now there is a "Service definition document" for each service entering Initial Services. Thus there is a Quality (or lack) of service defined for each signal. --      Björn Sent from my smartphone. Original message From: Tim Shoppa

Re: [time-nuts] How can I measure GPS Antenna quality?

Hi Atilla, Read the document below https://www.ngs.noaa.gov/ANTCAL/docs/NGSantcalprocedures.pdf And the reference within         antenna_README.pdf Antennas are generally not calibrated individually by the user. You make sure the antenna you buy are in the ANTCAL or Geo++ lists. Any use of a snow

Re: [time-nuts] L1 L2 choke Ring Question

Hi, There is(was) a 26dB lna in that antenna. --    Björn Sent from my smartphone. Original message From: Magnus Danielson Date: 20/11/2016 21:42 (GMT+01:00) To: time-nuts@febo.com Cc: mag...@rubidium.se Subject: Re: [time-nuts] L1 L2 choke Ring

Re: [time-nuts] Ashtech Z-12 firmware?

Hi Gregory, For a long time ftp://ftp.ashtech.com was useful. --      Björn Sent from my smartphone. Original message From: Gregory Maxwell Date: 27/08/2016 01:34 (GMT+01:00) To: Discussion of precise time and frequency measurement

Re: [time-nuts] Q/noise of Earth as an oscillator

A bit short on the phone... Both the ECI and ECEF frames are rotating at sidreal rate. The earth rate is (a small) part of the navigation equations. Thus its needed in inertial nav. Glenn, look at the performance of the big land RLGs - NZ and German that were linked last week. How much better

Re: [time-nuts] Q/noise of Earth as an oscillator

http://www.prc68.com/I/Sensors.shtml#Gyroscopic "A note on gyros.  When located in a dynamic platform, like an airplane, the gyro needs to be located at the center of mass of the vehicle.  This way when the plane banks, pitches or yaws the gyro will only respond to the angles.  But if it's

Re: [time-nuts] Warped back to 1993

As has been discussed here before. The GPS firmware programmer finalizing his stuff at GPS week X (approaching 1024) will make sure his receiver will survive until X weeks into the next era. What X is is hard for the end user to know. 1024 weeks is long time beyond normal warranties.  I have

Re: [time-nuts] Trimble Nortel GPSTM Boards

Hi Nigel! This has been discussed before in time-nuts. I have two of the big boards, but they are not running right now. If I remember correctly the big ones are more of a cost reduction model compared to the 2 board split solition. Giving lower SV snr than the split version.  But my ran just

Re: [time-nuts] Story in the Economist about GPS jamming

Satnav are not LEO but MEO. Which is good - less sv to cover the earth. Less good because distance is higher compared to LEO regarding signal power at earth.  -- Björn Skickat från min Mobil  Originalmeddelande Från: Scott McGrath scmcgr...@gmail.com Datum: 2013-07-30

Re: [time-nuts] Lecia L1 GPS chokering antenna voltage,

Hi, Is the antenna identical to this? http://www.aeroantenna.com/PDF/AT575-90_G.pdf http://ebookbrowse.com/at575-90-g-pdf-d359926216 (alternate link) Do you have some pictures of the antenna? In particular the antenna element? Aeroantennas of this vintage is usually RG which

Re: [time-nuts] Lecia L1 GPS chokering antenna voltage,

Good! N  is supposed to go to north, yes! But for this antenna it does not matter... longer story below.  This is used when you do phase differential stuff. Which usually means L1/L2 stuff and specifically antenna calibration data for az/el. I cannot find any calibration data. 

Re: [time-nuts] Leica L1 GPS Choke Ring Antenna

I have two chokerings on my roof. Get something to mount a TV antenna or a small satellite dish. Use a threaded water pipe instead of the normal antenna mast. If this is the oem version from Aeroantenna (AT575-90), there are also 3 bolt holes around the outer rim. Given a flat surface its

Re: [time-nuts] Speaking of Costas loops (WAAS)

Hi everyone, Have not seen a reference to either the Fenton patent nor the Fruehof paper, which discuss using WAAS for timing with a dish antenna. http://www.freqelec.com/gps_gnss/waas_for_telecom_wp_5-06.pdf https://www.google.com/patents/US6445340 kind regards, Björn

Re: [time-nuts] Speaking of Costas loops

Attila, On Wed, 3 Jul 2013 08:29:02 -0400 Bob Camp li...@rtty.us wrote: There are two batches of GPS / WAAS sats up there: 1) The ones with numbers above 100 that are geosync and that only do WAAS 2) The ones with numbers = 32 that do nav. These are not geosync. I believe the only ones

Re: [time-nuts] GPS antenna splitter

Both 'GPS Networking' and 'GPS Source' do good GPS splitters. Compared to Mini circuits type of splitters you will get the necessary dc-blocks and biasTs built in. Compared to HP/Agilent/Symmetricom splitters you will often get both L1L2 through. On Epay they often cost less.  Some example

Re: [time-nuts] 9390 GPS RX

Hi Mark, Just a Follow up, [..] Bah, I just noticed the GPS day is wrong, I think we are ~142 but its saying 278, Is that a GPS receiver bug? If it gives the correct time, it is very likely it is 1024 weeks off. Check what (today - 1024*weeks) gives you in day of year. -- Björn

Re: [time-nuts] pin-wheel antenna

Hi Dave, On 04/21/2013 10:32 AM, David Kirkby wrote: On 20 April 2013 20:52, Tom Van Baakt...@leapsecond.com wrote: For the rest of you: http://www.leapsecond.com/images/gps-pinwheel-1.jpg http://www.leapsecond.com/images/gps-pinwheel-2.jpg It's a thing of mysterious beauty. And the

Re: [time-nuts] antennas was Re: Common-View GPS Network

Magnus, Jim, On 04/18/2013 04:00 PM, Jim Lux wrote: On 4/18/13 12:01 AM, Chris Albertson wrote: If I read the paper correctly you can skip the choke ring if you mount the antenna on top of a 2 meter or longer mast. Iron pipe comes on 10 foot lengths. The choke ring is for portable survey

Re: [time-nuts] Common-View GPS Network

Chris, Chokering is not needed.  Measured quality antennas are listed at      http://www.ngs.noaa.gov/ANTCAL/  Or at         http://www.geopp.de/index.php?sprachauswahl=enbereich=0kategorie=34artikel=62 /Björn Originalmeddelande Från: Chris Albertson

Re: [time-nuts] GPS antenna??

There are even purpose builtglass mount antennas-arrangements for sale. http://www.antcom.com/documents/catalogs/Page/2G1215A-GMS-X_L1L2GPSAntennas_78.pdf -- Björn Alan, I used to do a lot of my Datum demos with customers with antennae up against a window as outside access wasn't

Re: [time-nuts] OT - DC-10 gyros

Hi Bill, Well, I can come up with something topical, read on. :) [snip] Topical in a more abstract way, strapdown systems really are very interesting. They require precise integration of the rate output over time to derive velocity and position, and really weren't practical until the 70's

Re: [time-nuts] One Kg Quartz Resonator

Isn't it defined for zero sea-level, that is standard acceleration? How do you define sea level? http://en.wikipedia.org/wiki/EGM96 http://earth-info.nga.mil/GandG/wgs84/gravitymod/egm2008/egm08_wgs84.html Daniel Kleppner's Time Too Good to Be True in Physics Today, March 2006 pointed

Re: [time-nuts] Strange GPS behaviour

Hi Magnus, 2) Timing versions might get an upgraded oscillator. Maybe a TCXO instead of a standard XO. Don't think so. The noise and systematic stability is as important for positional as for timing versions, the timing version can benefit of the fixed position. Look at the uBlox6 lineup.

Re: [time-nuts] Strange GPS behaviour

Hi, On 12/28/12 9:14 PM, Michael Perrett wrote: Bob, That is simply not accurate - if the solution rate is 1/second, then all parameters are solved in that time frame. There are 4 indpendent variables and minimal processing power is required to solve all four equations. Although I am not

Re: [time-nuts] Strange GPS behaviour

Hi Bob, I am curious about the sacrifice time and get better position. I have not seen any discussions about that in manuals, books or papers. Do you have reference? What would be the difference between timing and navigation versions of cheap commercial receivers? 1) Timing receivers are often

Re: [time-nuts] clock-block any need ?

Magnus, Doing ~200 us for a non-trival network with real data on it sound about right. What kills many assumptions is that the noise-forms fail most of the normal assumptions about noise. It's not zero mean, it does not have a static mean, it does not have a static variance, it is not

Re: [time-nuts] Thunderbolt oven / non-stable operating temperature

Warrenm tvb posted Were you able to test how quickly, or how well, the filter learned the tempco of the OCXO? Only at a couple of very general data points. Using a very Bad unit, the Kalman filter had an effect, although not very good in under 1/2 day. After a week or so on a good

Re: [time-nuts] Best phase detector / mixer for 100MHz?

Jim Lux wrote: On 11/26/12 10:11 AM, Demian Martin wrote: I asked Wenzel about mixers for phase noise measurement and they directed me to Marki Microwave as what they use: http://www.markimicrowave.com/2770/Mixers.aspx I have not obtained or tested any myself but it's a pretty solid

Re: [time-nuts] FE-5860a internal RF connector?

A premade U.FL to SMA cable worked fine for me, a few years ago in my 5680A. However as mentioned a few days ago, there are _many_ variations/generations of this unit. FEI might have changed the connector. -- Björn Was wondering if anyone ever confirmed the type of RF connector found

Re: [time-nuts] GPS splitter measurements

Paul, Azelio, Not at all the satellite splitters can be smart or passive. I use a passive so it has 1 dc path. But all of the other ports have dc blocks built in. The smarter units will direct the highest DC to the antenna. Its really diodes and I stay clear of those. To smart for there own

Re: [time-nuts] RFX GPSDO - Anybody played with one of these?

On 10/2/12 10:35 PM, b...@lysator.liu.se wrote: On 10/2/12 2:36 PM, saidj...@aol.com wrote: Hello Paul, thanks much for the feedback! Yes, we think we have identified a nice combination of oscillators, GPS, and firmware that seems to work pretty well. The GPSTCXO units cannot be

Re: [time-nuts] RFX GPSDO - Anybody played with one of these?

On 10/2/12 2:36 PM, saidj...@aol.com wrote: Hello Paul, thanks much for the feedback! Yes, we think we have identified a nice combination of oscillators, GPS, and firmware that seems to work pretty well. The GPSTCXO units cannot be compared to a lower cost $150 Thunderbolt in terms of

Re: [time-nuts] Symmetricom 58532A and 58536A group delay figures

With a warmed up tbolt and Lady Heather it is perfectly possible to measure/watch the delay by swapping the splitter in and out of the antenna cable chain. -- Björn Interesting that it's so far off from the 40 ns in the data sheet. I think the usually quote worse case. Both data sheets

Re: [time-nuts] WWVB Now a Monopoly

Dont you have GPS/Cs locked cell networks anymore in the US? http://www.endruntechnologies.com/cdma.htm -- Björn In the real world, if GPS does not work, the WWVB change means you either have to buy the XW stuff or go do something else. YMMV -John = On 9/26/12

Re: [time-nuts] HP-106 and Sulzer Quartz Crystals

Hi Paul, Here are two other links http://www.oscilloquartz.com/file/pdf/8607.pdf http://www.lysator.liu.se/~bg/timenuts/IMG_5119.JPG They are a bit shorter but bulkier than a FTS1x00-series USO. -- Björn Azelio thanks now I know what to look for. Have to say I don't actually ever see

Re: [time-nuts] HP-106 and Sulzer Quartz Crystals

. Regards Paul WB8TSL On Wed, Sep 19, 2012 at 4:00 PM, b...@lysator.liu.se wrote: Hi Paul, Here are two other links http://www.oscilloquartz.com/file/pdf/8607.pdf http://www.lysator.liu.se/~bg/timenuts/IMG_5119.JPG They are a bit shorter but bulkier than a FTS1x00-series

Re: [time-nuts] GPSDO Component Selection

Chris, On Sun, Sep 9, 2012 at 6:18 AM, Don Oconnor eg...@wowway.com wrote: Hello, I would like to design and build a microcontroller based GPSDO. And I have a couple of questions some of you may be able to answer. 1. I am going to use Trimble SMT GPS timing module but I'm

Re: [time-nuts] GPSDO Component Selection

On Sun, Sep 9, 2012 at 1:14 PM, b...@lysator.liu.se wrote: True for a cheap oem navigation receiver. Not true for a geodetic quality receiver, who usually have some options (external frequency input, PPS_in) to make them the best timing receivers available. However they are much more

Re: [time-nuts] GPSDO Component Selection

Hi Bob, Probably true for Motorola Oncores. Not very true for geodetic receivers. Until you have a receiver clock that is on par with the satellite clocks AND you are short on visable satellites. This might be true if you can load up a modern cesium in your vehicle, and go for a downtown urban

Re: [time-nuts] GPSDO Component Selection

Hi Bob, This argument has been done before on time-nuts... sorry for repeating. There are geodetic quality GPS reveivers, like the Ashtech Z12-CORS (with external 5-20MHz input - not the true Z12 Metronome) available for a few hundred dollars occasionally. I got my Z12 CORS for free, from a site

Re: [time-nuts] Trak 8821B ---- was Z3815A Internal SMA 10Mhz Output

Hi Nigel, Yes, I have the same version. We might have got it from the same UK epay source. The GPS did not work reliably, and I did start testing that module outside the Trak unit, and also tried VP(8chan) receivers that I had. Did not really conclude why the GPS did not behave properly. I was,

Re: [time-nuts] Trak 8821B ---- was Z3815A Internal SMA 10Mhz Output

Hi Nigel, With regards to the Oncore VP carrier phase measurement option, I'm not too sure that the 8821B does actually make use of that. The Z is a pure software option, to enable the phase capability already in all of the VP receivers. So you pay extra, but get exactly the same hardware.

Re: [time-nuts] Z3815A Internal SMA 10Mhz Output

Hi Nigel, Then there's the variant of the Trak Microwave 8821B, as just one example, that uses a 16.384MHz OCXO from which they derive a 2.048MHz output without 10MHz anywhere in sight. When I bought one of those a few years ago I assumed that all 8821Bs would be 10MHz GPSDOs, or some

Re: [time-nuts] T-Bolt Temperature

It would be a worthy hack (in the classic sense) to extract the Tbolt firmware and patch it to work with the current temperature chips. -- Björn Hi Just in case this inadvertently heads of in the wrong direction…. Lady Heather displays exactly what the TBolt firmware comes up with.

[time-nuts] TADD-1 replacement status

Hi, Have not seen any recent updates on the new TAPR 10MHz distribution amplifier design/production. What is the current status? -- Björn ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to

Re: [time-nuts] FRK specs.....

Hi Don, Bert: Interesting. I, too, have a couple of the HP 10811 oven-oscillators sitting on the shelf for several years, waiting for a project. I want to 'discipline' them, but really do not know how. Also look at John's modification of a Thunderbolt.

Re: [time-nuts] FTS 1200

Bert, Good that you got the EFC working! But I would be a bit suspicious of needing -13V. It seems from: http://www.ece.gatech.edu/academic/courses/ece4007/08fall/ece4007l01/al4/datasheets/symmetricon_oscillator_instructionsheet.pdf that the default EFC configuration is (0 to +10)V with a

Re: [time-nuts] FTS 1200

Hi Bert, I have a FTS 1200 that is off by about 2 Hz. Have decided to take a closer look. Does any one have technical Information I should study before I open it up. Thanks Bert Kehren The efc range on my FTS 1200 goes from about -1.5Hz to +2Hz (0V to +10V). Is your FTS1200 of even with

Re: [time-nuts] FTS 1200

Hi Bert, So the EFC does not work at all? (or did I miss something obvious?) /Björn The unit starts high and over 20 minutes comes down to 4.975 with 0 V on the EFC. Any voltage on pin 2 and it quits oscillating. Bert In a message dated 8/9/2012 7:06:48 P.M. Eastern Daylight Time,

Re: [time-nuts] HP 58503A

Doug, I ran into a wiki description of GPS using WGS84 a couple days ago. It included a mention of ESEC and it was something like: Earth Static, Earth Centric. I think I was following a link about the Z3801A. It referred to the fact that lat-lon is referenced to a static grid on the Earth

Re: [time-nuts] FTS1200, OSA8600, OSA8601 phase noise and ADEV measures

Bottom line, the large low-frequency spurs in the FTS plot at 1.4 and 2.9 Hz will be caused by one of these conditions: 1) A problem with the reference source(s) 2) A problem with the FTS oscillator itself 3) A normal characteristic of the FTS oscillator (maybe its spur specs weren't

Re: [time-nuts] 5MHz ocxo

Hi, Note that the 1804M, also has a 1PPS output. This is coming directly from the GPS module 1PPS. The Trimble SV6 module I have in my units is only good to 1us, almost a 1000 times worse than a Tbolt. I am not sure if the SV6 has a sawtooth error message giving a good estimate on how wrong the

Re: [time-nuts] HP-5065a advise and purchase decision

Tom, Chris, The HP 5065A is one of the best Rb ever made. /tvb (iPhone4) Have you or any other list member had the opportunity to take measurements on the ElmerPerkin/EGG Space rubidiums (in a lab environment)? http://www.excelitas.com/Downloads/DTS_Frequency_Standards_RAFS.pdf --

Re: [time-nuts] Widdershins

Direct GPS signals, RHCP, good! Reflections (multipath) LHCP bad! ;-) -- Björn It's also connected to handedness. widdershins means to go leftwise, deasil righthanded or rightwise. lefthandedness bad, righthandedness good. Threads righthanded usually, bunches of other stuff. Don

Re: [time-nuts] Thunderbolt cabling questions

Hi Chris, Even if this is the datasheet of a later version, it gives an overall picture of what you ask about. http://trl.trimble.com/docushare/dsweb/Get/Document-383329/022542-010B_Thunderbolt-E_DS_0807.pdf The Tbolt perform (even) better with stable temperature surroundings. 3m of antenna

Re: [time-nuts] Trimble/Nortel 45000 GPSDO

Hi Mark, I got in a couple of those Nortel GPSDO modules (marked 45000-00-B8 GPSTM). These are the single board version of the NTGS50AA modules that have a separate small front panel board.They are hardware and software compatible (mostly). Some immediate differences popped up. The

Re: [time-nuts] Thunderbolt GPS rollover

Hi again Mark, Most GPS receivers base their rollover point from their data of manufacture/firmware creation/etc. The week rolls over 1024 weeks after that. They tend to not be dependent upon when the actual GPS week rolls over. Better receivers have ways of inferring the actual week

Re: [time-nuts] Thunderbolt cabling questions

On Sun, Jun 10, 2012 at 2:50 PM, b...@lysator.liu.se wrote: ... 3m of antenna cable is no problem. Antenna position is more important than the exact type of antenna. I'd rather have a decent antenna at a very good site, than a very good antenna at a slightly worse antenna site 3M is

Re: [time-nuts] NTGS50AA, better than Thunderbolt

Hi Mark, My second NTGS50AA came in from Old Cathay. Seems to be working OK. A couple weeks of oscillator aging will tell more. This one originated from Guatemala City, Guatemala (the other one also came from Guatemala) The seller on Ebay has scaled back his dirty capitalist pig

Re: [time-nuts] Trimble/Nortel GPSTM (NTGS50AA) - working with Lady Heather.

Sam, Mark, Murray and others, Which pins on the large CPCI connector holds the RS422 serial port. Power is on row 1 and 4. -- Björn There was some discussion in Dec 2011 regarding the Trimble/Nortel GPSTM (NTGS50AA) which fizzed out after it was mentioned that Lady Heather would not work

Re: [time-nuts] NTGS50AA RS422

Murray, Bjorn, I don't know of an RS422 connection at the back of the NTGS50AA. There is a 'CMOS' level serial output (essentailly a monitor point) on the top pin, 7th row along from the end the power is applied. There are also 10MHz PECL outputs at the other end of the connector. I use

Re: [time-nuts] Why are 1PPS signals so skinny?

Mark Azelio, Or even 10V into 50ohm, 20us... See figure 3-4 in ICD-GPS-060. http://www.navcen.uscg.gov/pdf/gps/ICD-GPS-060B.pdf More modern 3-5.5V into 50ohm, 20us. http://contracting.tacom.army.mil/majorsys/jab/DAGR%20Interface%20Specification.pdf Above are two standards

Re: [time-nuts] Tbolt failure modes

Thanks everyone! On 05/12/2012 03:37 PM, Mark Sims wrote: It sounds like the -12V supply is used to generate the DAC low voltage reference. If it is floating, the DAC output will be unstable. If it is at a solid voltage, the DAC output will be stable. The standard EFC range for a tbolt

Re: [time-nuts] (no subject)

I like Less than $20... Not for Sale Sounds like vaporcrap to me... - Or 216 channels (GPS L1/L2/L2C/L5; GLONASS L1/L2; Galileo E1/E5A): http://www.javad.com/jgnss/products/triumph.html Have used Delta receivers in production at a former employment. They are very

Re: [time-nuts] Trimble Resolution SMT - good/bad/indifferent?

On 5/11/12 2:38 AM, Hal Murray wrote: Why in the hell would anybody build a 50 channel receiver? At most you MIGHT see 12 usable GPS sats... I don't think that I've seen over 10. WAAS should be fairly useless for a timing receiver. I can think of a couple of reasons. I'm sure there are

Re: [time-nuts] TU-60 Instruction to set NMEA output

Hi Merv, Hi, I am new to timenuts. Is anyone able to give me the binary command sentence/code to send to my Jupiter TU-60 to change it's output from Binary to NMEA please? I assume it has to be a binary command starting with @@ but I am unable to find a suitable command using Tac32

Re: [time-nuts] question about Thunderbolt geo acuracy

Hi Tim, The answer is NO. Even though decent accuracy can be had with long averaging. It was discussed a few years ago on this list. -- Björn Hi all, Hope this isn't too chat roomy, however, I have need of a survey precise geolocation type gps. I was wondering if the precise timing

Re: [time-nuts] question about Thunderbolt geo acuracy

Attilla, On Thu, 10 May 2012 22:50:15 +1000 swingbyte swingb...@exemail.com.au wrote: Hope this isn't too chat roomy, however, I have need of a survey precise geolocation type gps. I was wondering if the precise timing abilities extend to its precision in position output? I have a

Re: [time-nuts] Allen Osborn Turborogue SNR-12 RM

Hi Thomas, AOA used to be in Westlake Village, north of LA. They were bought by ITT some years ago. ITT more recently split, I think they should be within ITT Exelis. Maybe you could contact them?

Re: [time-nuts] Can M12+T be improved?

In message 727909549.133407.1336592785570.JavaMail.mail@webmail11, billdobson @uk2.net writes: The idea is to remove the onboard TCXO and replace it by a 16.368MHz clock synthesysed from the OCXO, I asked one of the motorola engineers about this long time ago for the UT+, and he said

[time-nuts] Tbolt failure modes

Hi group! Just got a few Thunderbolts. It is a few PN 39448-61 and one PN 38223-61. Date codes from 9932 to 0025. This is the normal version with a 24VDC power board and Tbolt board integrated in a small AL box with red markings. One of the receivers is having a problem. Measuring from the

Re: [time-nuts] Tbolt failure modes

Hi Bob, The DB-9 looks fine even with magnifying glass. The good one has a MAX232EWE IC, the faulty has a TC232EOE. I see RS232-level coming in at pin 13 and going inside the Tbolt at pin 12 (ttl level).So there should be no problem there. Have also swapped PSU board, so the problem is inside

Re: [time-nuts] Tbolt failure modes

Hi Magnus, On 05/08/2012 11:58 PM, Bob Camp wrote: Hi The first thing to check is the soldering job on the DB-9 connector. Second thing to check is the RS-232 level translator IC. (RS-232 in should create TTL etc) Does not explain why the OCXO remains stuck as if it was untrained. I

Re: [time-nuts] Tbolt failure modes

Agreed, the CPU is not working... check the 3.6864MHz crystal under the CPU. If it is possible to locate the reset signal... Time to get some sleep... I found the crystal. It is not easily probeable when mounted on the PSU board. Also the power rail has to short pins to accept the external 3

Re: [time-nuts] FS700 antenna

Magnus, Hi Stan, On 05/05/2012 08:18 PM, Stan, W1LE wrote: The classical approach: Look at the spectrum and notch or filter out what is not wanted. The FS-700 does have a set of filters and a front panel LORAN output (w/gain) to monitor with a spectrum analyzer for filter settings. I

Re: [time-nuts] Setting up PRS10 with M12+T GPS

Jerry, Magnus, Considering the M12+T PPS noise, you won't need anything stellar. A PICTIC II will do just fine... or if you trust the PRS-10 readings, run from that. What would make this better would to use a sawtooth-correction to PPS delay setup, as the PRS-10 measurement resolution will

Re: [time-nuts] Setting up PRS10 with M12+T GPS

The phase of the PPSOUT and the generated 10 MHz will probably not align up, something which is critical to some applications. Yes, for example the DVB-T SFN requires the PPS and 10MHz phases to be aligned, better, not to move. This requires to slightly alter the 10MHz to keep the PPS aligned.

Re: [time-nuts] Setting up PRS10 with M12+T GPS

Hi Magnus, |---| | | | PRS10APRS10B | |---PPS IN PPS OUT--PPS IN PPS OUT--| hoping that the font doesn't mess up the

Re: [time-nuts] Setting up PRS10 with M12+T GPS

Magnus, Tbolt PRS10A PRS10B 1pps --PPSIN PPSOUT -- PPS IN PRS10A slowly following the Tbolt (PRS10A PT8) PRS10B quickly following the PRS10A (PRS10B PT0) Ok? Yes, but if this is a free-running thunderbolt (I think you said something about that) then PT8

Re: [time-nuts] Setting up PRS10 with M12+T GPS

Yes, all made clear. Trigger on Ch.4, I see. You have written green: 10MHz PRS10B but it must be A, otherwise it seems that the PPS and the 10MHz of the PRS10 are not phase aligned. Moreover, the PRS10B seems to track the PRS10A with some delay as the 10MHz from A spreads on more than 5nS

Re: [time-nuts] Setting up PRS10 with M12+T GPS

Björn, On 05/03/2012 12:30 AM, b...@lysator.liu.se wrote: Magnus, Tbolt PRS10A PRS10B 1pps -- PPSIN PPSOUT -- PPS IN PRS10A slowly following the Tbolt (PRS10A PT8) PRS10B quickly following the PRS10A (PRS10B PT0) Ok? Yes, but if this is a free-running

Re: [time-nuts] Ashtech 3DF GPS

Hi Stan, On more or less of a whim, I found and bought an Ashtech 3DF GPS. The interesting thing about this particular GPS is that it uses four separate GPS antennas mounted in a diamond pattern about 1 meter on a side and can compute not only the usual stuff, but also heading, roll, and

Re: [time-nuts] Trimble recommends RG-59 Antenna Cable.

Hi Ken, Hi Time-Nuts guys, I was reading the Trimble Thunderbolt manual section 2.1.3 (Antenna Cable). Trimble recommends using RG-59 cable which is 75 ohm coax. Is this a typo or is this correct? I thought that the Trimble Thunderbolt would use a 50 ohm cable and antenna. Thankyou

Re: [time-nuts] Sw for pm6680B

Hi, Hi the Gang, I just got not cheap but for a quite reasonnable price a legacy Fluke PM6680B counter. This toy seems to be very interesting to play with, I already have a 5370B but this new toy I got seems to be more fancy to play with, have to be confirmed. I know there is a software

Re: [time-nuts] Trimble Thunderbolt GPS Antenna

Hi Ken, Hi, Time-Nuts guys I just baught a Trimble Thunderbolt on ebay. I am in need of an antenna, there are so many on ebay I am not sure which one to get. Maybe someone could point me in the right direction? Thankyou Ken Kubick How long antenna cable do you need in your location?

Re: [time-nuts] GPS, USGS Early Earthquake Warning

Hi Brooke, Hi Tom: They do use two different seismometers at each location, a large movement and a sensitive. http://www.prc68.com/I/Seismometer.shtml Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/Clarke4Congress.html It is a bit fun that the

Re: [time-nuts] PRS-10 input and output calibrations

Magnus, Interesting! Have a couple of PRS-10s at work that we wanted to lock together. We never got one to track the other in a reliable way. -- Björn Fellow time-nuts, Anyone who has tried to calibrate the PPS input and PPS output interpolators of the PRS-10? The output calibration

Re: [time-nuts] PRS-10 input and output calibrations

With factory default settings with 2 PRS-10s, connecting 1PPS_out from one unit to 1PPS_in on the other, would not align the 1PPS_out pulses. They were off by several hundred of ns. It was probably an operator error somewhere. We just did not find the error in the time frame we had available. --

Re: [time-nuts] Lucent 40 dB Antenna

Hi Joe, 40dB is not needed when you have a short (10m) /good antenna cable. Then 26dB will be plenty fine. Howver going to 20 or 30+ meters using standard RG58 will be a problem with 26dB. Ofcause what matters is the attenuation at L1 with your cable. Better cable can be longer... You do not

Re: [time-nuts] Re-radiating a GPS signal...??

Not at all! The (first) receiving antenna defines the position you get out of a long antenna cable or a reradiating system. The delays in LNA, filters, cables, rerad antenna, free air between rerad antenna and final receiving antenna ALL goed into the receiver clock error. This is clear both from

Re: [time-nuts] Best location for a GPS antenna...?

Rerad-systems are getting controlled in Europe too. http://www.etsi.org/deliver/etsi_en/302600_302699/302645/01.01.01_60/en_302645v010101p.pdf Any reports on how quick this is going? Where I live, there are rules, but not many are aware of them. -- Björn You must read:

Re: [time-nuts] Re-radiating a GPS signal...??

It is well known that vertical accuracy is worse by about 1.8 times the horizontal accuracy. It is true this is geometrically caused. In indoor scenarios high sensitive receivers have a vertical bias due to excessive multipath. More or less all received signals have bounced multiple times to reach

Re: [time-nuts] Thoughts on lightning protection measures....

Said, The ground is a decent thermal isolator. And will in nordic countries not often go deeper than about 1 meter. You need to build your houses foundation deep enough to stand on non frozen ground. Otherwise your house will move to much with the seasons and likely break. It is not that hard to

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