[time-nuts] test message
My email address book got corrupted. Hopefully this will work... ___ time-nuts mailing list -- time-nuts@lists.febo.com -- To unsubscribe send an email to time-nuts-le...@lists.febo.com To unsubscribe, go to and follow the instructions there.
[time-nuts] Grandfather clock sync'd to 1PPS
I also disciplined a friends grandfather clock. I used a small servo to nudge/impulse the pendulum. It used 24 impulses/minute. Worked rather well for a crude hack. No mods were done to the clock case/mechanics. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] making crystals
I built a 405 nm laser head for my mini-mill. It could cut features with a resolution of around 4 microns. I mainly used it to cut solder paste stencils. A friend used it to expose photolithography masks on quartz plates and silicon wafers. Also to tune some vibrating reed like thingies by ablating a coating. Alas, the laser driver died and the company that made them is out of business... >I wonder if someone has a laser rig that could programmed to "draw" the pattern on the resist at the right scale. As I recall, 50 MHz has a wavelength of about 60 microns, and your transducer fingers are half wavelength apart. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Ebay Huawei Ublox M8T Modules
Can somebody point me to a connection diagram for the external connections tp the carrier boards? ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Voyager space probe question
I once bought a spool of tungsten-rhenium alloy wire on ebay for dirt cheap. A few weeks later a guy contacted me and offered a lot of money for it. Turns out they used it to rebuild TWTs. > I wonder what sort of cathode material they use? ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] OCXO housings - Why copper and not iron/steel?
And (if I remember the numbers properly) Isotopically pure diamond has twice the thermal conductivity of natural diamond. There are places that make diamond-like carbon thermal pads. Also places that make actual diamond ones (which are not as expensive as you would think), - > Actually, diamond has five times better thermal conductivity than silver, so is the most conductive element, although graphene is suspected to be better still. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] LH and long-term oscillator measurement
There is a command line option (and maybe a direct keyboard command) for setting the plot queue size. Sorry, I'm away from a Heather machine and don't remember what it is. You could also write a log file or receiver raw data stream capture file and extract the data from that. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] ! PPS Source
The Tbolt won't track sats if the DAC is manually set too far off the value needed for 10 MHz. -- > And now your GPS chip won't even boot or work right if the user's 10 MHz isn't there, or isn't accurate enough, or is still warming up, or if the user's 10 MHz has too much phase noise or instability. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] 3D printed tourbillon clock
https://www.youtube.com/watch?v=E9prY3ky6Bo ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Precise pendulum
https://arstechnica.com/science/2020/06/tiny-pendulum-may-reveal-gravitys-secrets/ ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Lady Heather - sort satellites by dBc
You can sort a column either ascending or descending. Specifying which one to use with a click on the column header isn't easy or intuitive. Clicking anywhere on the sat info table zooms the screen to a detailed sat info screen -- >I still think that a "standard" click on column header to sort would be more intuitive. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Lady Heather - sort satellites by dBc
The GC menu has options for sorting by any column. You can chose an ascending or descending sort. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] UBlox F9T and Lady Heather
Yes indeed, there is a version that supports the F9T/F9P. Unfortunately the code is currently in a university building that is locked down. No idea when I will get access to it again... ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Gravity, solid Earth tides
If you are interested in solid earth tides and gravity effects Lady Heather can calculate / display / plot them in real time for your location. BTW, one of the surprisingly large factors in accurately calculating the moon position is the position of Venus. Also, Jupiter gets into the equations. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] OCXO Support Board
One thing that I recommend is that after completing the layout is to: 1) step back and wait a few days 2) enjoy a few adult beverages while waiting 3) go back a re-check everything 4) send it out to the board house You'd be surprised how often simple, subtle, not so subtle glitches/tweaks/improvements show up after a pause in the process. --- > Once you get going, a board is a weekend project. Indeed, a simple board > might be an evening project. There’s not a lot involved. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Quality of timing mode GPS vs survey accuracy
Be aware the some receivers report altitude in MSL (mean sea level) and others use AGL (height above ground level). Depending upon where you are and the conversion model, there can be over 100 meters difference. --- I >if I take a survey > with several GPS receivers will they all get the same answer? ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] FE-5680A - Newbie capacitor question
If it's a filter cap on the output of an LDO voltage regulator (at 1 uF it is probably not) be aware that a lot of LDO regulators have problems with very low ESR caps. Check the LDO data sheet for acceptable values. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] power supplies
Yes, Power Designs units are VERY good. Some (their precision models) are insanely good. They have a cult following and can be a bit pricey these days. There are lots of posts on eevblog.com about them. Dave did a video on one of the precision units. https://www.eevblog.com/forum/testgear/power-designs-power-supplies-database/msg2801534/#msg2801534 - >Spend some time on eBay looking for Power Designs bench supplies. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] TICC / TimeLab fun
Lady Heather's TICC parser does not expect alternating ABAB readings and handles the ABAB vs ABBA situation properly. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] questions about oscilloquartz 10MHz module
I've been using 8663's for years. I've put many of them in freq counters. Their phase noise is fairly good, but not stellar. Their temperature stability is more than excellent. Aging drift tends to be far better than spec. As with all things OCXO, YMMV ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Using HP5071A with dead tube along with GPS
I've actually done this... Lady Heather has built in "alternate disciplining" algorithm for the Thunderbolt. I tricked up some code to use this along with a TAPR-TICC to make a GPSDO. The first (rather crude) hack worked pretty well. I haven't had a chance to do it properly... yet. The idea was to allow the 5071A to run with the CBT in standby for applications that do not require the cesium goodness. - > A fun (and actually very useful) project would be to turn it into a GPSDO ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] tracking position & orientation
NRCAN / csrs-ppp will do L1 only data. Typical results have errror ellipses in the 300-500 mm range. It also seems to be the only free site that handles RINEX V3.xx data. They only use GPS and GLONASS measurements, -- >I do not know of any free sites that will post process “L1 only” data. Without post processing, you will not get mm level results. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Antique pendulum clocks
Whenever Dollar Tree those solar cell powered "nodding" figurines on sale (for $1) I pick one up (btw, they haven't had any for several months). A friend of mine loaned me his 16 channel 10 ns FPGA based time stamping counter. So, I picked out 16 different nodders (out of 100 or so unique models... do I have a nodding problem?), added opto-interrupters, put them in a closed and brightly lit bathroom, and collected nodding data for a day. Alas, the hard drive in the 20 year old laptop that collected the data crashed before I could really analyze the data. Someday, I hope to repeat the experiment... -- > I'm waiting for someone to have hooked up a bunch of cheap metronomes on a common base to an array of TICCs... ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Used ESE ES-911/GPS/NTP Master Time Clock
I got my ESE ES-911 to work.The problem that I was seeing was that the unit was not seeing data from the GPS receiver... it would not show a GPS lock, even though the GPS receiver (a Motorola M12+) was working properly.Probing around the ESE motherboard showed the GPS receiver was not sending any data. I assumed (improperly) that the GPS receiver was not being initialized to send data by one of the two microprocessors on the ESE motherboard (no data seen being sent to the GPS receiver). There are two batteries in the ES-911. One is a 6V 1.2Ah gel cell. The other is a tiny ML-621 rechargeable lithium coin cell on the back of the GPS board. Both batteries were dead. It turns out that the microprocessors do NOT initialize the GPS receiver! You have to do that over the "auxiliary" data port (the DB-25 connector). Pin 2 is the "config" pin. It is a RS-232 level serial input connected to the GPS receiver RXD input pin. There is no external connection to the GPS TXD signal so you cannot monitor the GPS receiver. To initialize the GPS receiver, I built a two wire adapter cable to connect a PC serial port to the ESE "aux" connector (PC pin 3 (TXD) to ESE pin 2, ESE pin 7 (ground) to PC pin 5. I then used Lady Heather configured to talk to Motorola receivers (heather /rxm /serial_port#) This sends commands to initialize the Motorola receiver on the ES-911 motherboard. Voila... ESE-911 started working properly. Note that Heather will complain about not seeing any data from the receiver since the ES-911 does not have any way to send the GPS serial data to the outside world. While connected to the "config" port you can use the "PC" keyboard command to set the antenna cable delay. Note that this will be a "blind" command with no apparent response back to the computer. After initializing the GPS receiver I moved the PC serial port cable to the ES-911 "broadcast" connector and re-started Heather. Heather v6.30 and later can decode the ES-911 time codes sent out the "broadcast" port. So if your ESE ES-911 loses input power, 6V backup battery power, and the GPS coin cell drains then you will need to fix the battery problems and then manually re-initialize the GPS receiver in order to get the device working again! ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] FA-2 questions
If you have a terminal connected, the FA2 outputs the version info when you switch it on. --- > I'm not sure of a way other than turning it on and quickly reading the screen > to see the firmware rev. Mine is V20190827. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Used ESE ES-911/GPS/NTP Master Time Clock
I got in one of these... alas, the GPS module does not seem to work. It never locks to GPS. Alas, there is no status information to tell what is going on. These units only output a time code (in one of 4 different formats). All configuration is done via DIP switches. They do not output any satellite or other information. For what it's worth... Lady Heather can now read the time code information and use it to drive the clock display. I am going to try putting in a new GPS receiver. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Authoritative Source for Lady Heather
The two real sources are ke5fx.com and EEVBLOG ke5fx.com has the "official" fully blessed release. It is currently at v5.0 This package has the nifty installer program. The EEVBLOG site (https://www.eevblog.com/forum/metrology/lady-heather-v6-beta-for-windows-exe/msg1434005/#msg1434005) has the latest "beta" release. This version has support for several new devices and several new features. It gets periodically updated. EEVBLOG used to have a 1MB file limit so the source code was on tinyupload.com. EEVBLOG has recently raised their limits to 5 MB, so everything can now go there. I am planning on getting a new release (v6.30) out in a week or two. I am also planning on getting Heather onto github. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] can of worms: time-of-day in a community radio station
Well, Lady Heather will do all that (plus handle time zones, DST, and leapseconds). A Ras PI (even a Pi Zero) works very well. I have just added a "radio station studio clock" display mode. This clock display is driven by the system clock which is hopefully steered by NTP. Default update rate is 10 Hz. It can also be driven by a GPS device or GPSD. Heather also supports a full screen digital date/time clock. I just bought a nice 24" HDMI monitor for $60. Add a $10 Pi Zero W and another $10 or so for power and cables. And maybe $10-$30 for a battery backup (many people use USB power banks) so you don't have hiccups due to generator switchover, etc. --- > It seems that you should be able to get a LCD display (doesn't have to be high res), hook it up to a RPi or something commodity, and find software that displays a round wall clock, and syncs to NTP.___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] FA2 internal OCXO orientation sensitivity
It's not due to thermal issues. The freq change due to tip is way too fast for that. --- > It’s also possible that the sensitivity is due to thermal issues. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] FA-2 Frequency Counter Display
I doubt that you can find a suitable larger replacement display. Besides interface compatibility issues, a larger display will probably have more pixels than the FA2 firmware expects. I have added FA1/FA2 support to Lady Heather. It includes a command (ZF) to zoom the screen to a full screen frequency counter display. A Raspberry PI with the 800x480 touch sceeen display works very well. Heather supports running with two FA1/FA2 counters (or even an FA1 and a FA2). See the attached screen dump for the resulting display. The plot stats are from Lady Heather's calculations and not the FA2's calculated statistics. The main input device is a FA2. The auxiliary input device is a FA1. I'm working on simultaneously displaying statistics for both devices... but the PI touchscreen does not have enough space. >but I'd be more than happy to have it less wee and relocate it into a larger >box if it was practical to replace that display with something bigger that >could actually be read from a bit further away than an inch or two when >running standalone___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] FA-2 questions
No, the power switch turns off all power. See my post about the warm up characteristics of the FA2 OCXO: http://lists.febo.com/pipermail/time-nuts_lists.febo.com/2019-October/097803.html --- >First, does the internal OCXO run when the power is turned off? ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Question for my new GPSDO
The BME280 does temperature, humidity, and pressure. They are very nice. Beware of BME280 boards sold on Ebay, etc. A lot of sellers ship BMP280s. One way to tell is the BME280 is in a square package and the BMP280 is more rectangular. Also be aware that some BMP/BME280 libraries seem to have some error in their humidity calculation code and produce incorrect results. -- >The very similar BME280 also measures humidity ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] FA2 internal OCXO orientation sensitivity
The first time that I tried to set the FA2 internal oscillator frequency I tilted the case so that the screen was facing down and the adjustment screw was facing up. I got it on frequency, but when I placed the unit with the bottom of the case facing down the oscillator was 0.032 Hz off. So I did some more testing with the case in various orientations. It looks like the frequency is fairly insensitive to orientation except for tilt in the front-back axis where it is around +/-1 milliHertz per 3 degrees of tilt (which seems rather high to me). If you are using the FA2 in a mobile application pay close attention to the front/back tilt of the case. F:001000.001619430 bottom down F:001000.001687723 F:001000.001946380 F:001000.001902348 F:001000.001692710 F:001000.001663366 F:001000.001712156 F:001000.001760899 F:001000.001590295 F:001000.001648737 F:001000.001922004 bottum up F:001000.002214679 F:001000.002209653 F:001000.002063463 F:001000.001912133 F:001000.002556087 F:001000.002775519 F:001000.002053697 F:001000.002014587 F:001000.001570725 F:001000.033927950 screen down F:001000.033435257 F:001000.032562128 F:001000.032625399 F:001000.032098574 F:001000.032225335 F:001000.032391257 F:001000.032571790 F:001000.032922928 F:000999.971298357 screen up F:000999.967820455 F:000999.967859533 F:000999.967986393 F:000999.967800925 F:000999.967947314 F:000999.968327835 F:000999.968252960 F:000999.968030373 F:000999.998658455 left edge down F:000999.998985308 F:001000.000419484 F:001000.002063510 F:001000.003292634 F:001000.003956045 F:001000.002448722 left edge up F:001000.002029197 F:001000.001917045 F:001000.001985357 F:001000.002012571 F:001000.001980588 ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] FA2 internal OCXO warm-up time
I did a test of the FA2 internal OCXO warm up time. I powered mine down for 4 fours and then powered it up and measured the frequency as it warmed up. It looks like it takes 45 minutes to stabilize. Note that it took a week of constant power for the oscillator drift rate to settle down. The drift on mine seems to be around 0.00025 Hz/day. I need to do a longer test to better weed out temperature sensitivity. BG7TBL internal oscillator warm up time: Minutes Freq error 0 221 Hz 1 17 HZ 2 0.2760 Hz 3 0.0500 Hz 4 0.0350 Hz 5 0.0240 Hz 100.0130 Hz 150.0080 Hz 200.0060 Hz 250.0050 Hz 300.0042 Hz 350.0040 Hz 400.0034 Hz 450.0021 Hz <--- stable 500.0025 Hz 550.0022 Hz 600.0020 Hz ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] FA2 Programming
The command $Cxx* will set the contrast. xx can be 00 to 63. Ignore the measurement data that the FA2 sends continuously and just type over it (or disconnect the input signal). It should respond with something like CONTCOK if the command is accepted. Note that the value is stored in EEPROM and there is no way to read back the current setting. Note that the FA2 (rather weirdly) uses the '*' character as the end-of-line character when sending commands instead of the much more rational carriage return key... perhaps China has a shortage of keystrokes ;-) I am currently adding the various FA2 config commands to Lady Heather. --- >I am able to connect using USB and tried Putty in serial mode. When I connect the port, the FA2 dutifully starts outputting the measured frequency but that's the extent of my control, or lack thereof. Has anyone more skilled than I done any programming? ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] FA2
The "official" 7" PI touchsrceen (800x480) sells for $60 at MicroCenter. Lady Heather has a built in touch keyboard or you can use the PI's touch keyboard routine. But touchscreen keyboards can be a pain to use for a lot of typing. Heather lets you attach script files to the function keys. The Smartipi Touch case is very nice. It sells for less than $20. They also sell extended back covers where you can mount some boards, etc. My alarm clock is built into one (uses a SIRF GPS module and a battery backup board): https://smarticase.com The combination won't be as cheap as a low end Android, but will probably be a lot more functional. --- >Raspberry Pi has no display, no keyboard. If you add those, you far exceed the cost of a 7" tablet and you still have a pile of stuff that barely fits in a shoe box let alone in a decent looking enclosure and that you would not want to leave on a table unattended. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] FA2
Maybe try running Lady Heather on a Raspberry PI? My PI config is a PI with their "official" 800x480 touchscreen all mounted in a SmartiPI case/stand. Heather can collect data from the FA2 and echo it to a file all while displaying the data and calculating and plotting ADEV/HDEV/MDEV/TDEV and MTIE, -- > To day making long term observations ties up a PC or Laptop with fans and a > HP53132. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] FA2 counter Picture
It looks like the OCXOs used on some of the Trueposition GPSDOs (which also used some Bliley OCXOs). I really like that it has an internal OCXO available. You don't have to use it if you have a better reference source handy, but it can be very convenient if you don't. BTW, the drift rate on my OCXO is now around 0.0009 Hz / day. One 12 hour interval was 0.5 Hz / day. - >They probably got the OCXO for less than $5 on the internal Chinese market …. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] FA-2 Counter Questions
Can you post a copy of the manual? Nobody that I've talked to has seen any manual or documentation.We've assumed that the "P" means the PLL is locked and the '*' indicates the unit has an input signal. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Talking Clock
It would be pretty easy to teach Lady Heather how to do it. Heather already supports several different audible clock. One issue would be constructing the message from several snippets. Currently Heather plays sound files asynchronously and if you start one file before the last one has completed they get mixed together. Another issue to work out is the length of the combined message so that you know when to trigger playback. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] FA2 low pass filter
A user on EEVBLOG asked his FA2 seller about the low pass filter. It is apparently 150 kHz. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] FA2 internal reference oscillator test
This morning the drift rate is down to 0.001 Hz/day. It's settling in faster than expected. --- > The oscillator drifted at the rate of 0.00635 Hz / day, but the drift rate > is slowing down (it's now around 0.005 Hz / day). It will be interesting to > see how it ages in over the next few weeks. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] FA2 internal reference oscillator test
I did a test of the FA2 internal OCXO oscillator. The FA2 uses this as the reference if you don't connect an external reference. You can adjust the oscillator frequency with a small pot on the back panel. As shipped the oscillator was 0.10 Hz off. I adjusted to be within 0.003 Hz (I didn't try to fiddle it to be spot on). I did the oscillator test by having it measure an HP-5071A cesium oscillator (10 MHz) which is assumed to be (and is) spot on and very high quality. Any deviations from the noise floor test that I did earlier are mostly due to the FA2 internal oscillator. The wobbles in the frequency plot are due to air conditioning. The oscillator changes freq by around 0.00025 Hz / degree C. The oscillator drifted at the rate of 0.00635 Hz / day, but the drift rate is slowing down (it's now around 0.005 Hz / day). It will be interesting to see how it ages in over the next few weeks.___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] FA2 counter
Attached is the FA2 noise floor test. The FA2 was clocked by a HP-5071A 10 MHz output. The FA2 frequency input was the FA2 reference output signal (which should be the 5071A output, maybe with some buffering distortion). I didn't have the cables and T-adapter handy to split the 5071A output into the FA2 ref and signal input connectors. The plot also shows the phase measurement of the input signal. I am now looking at the FA2 internal oscillator performance. Mine was shipped with it set 0.1 Hz high. I use the tweak pot to get it within 0.003 Hz (with a little patience and twiddling you should be able to get it to +/- 0.001 Hz. I am measuring the FA2 internal osc performance by running the FA2 with its internal osc as the reference and measuring the 5071A 10 MHz signal.___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] FA2 counter
A list member did some experimenting with the unit and came up with this very useful information: "press and hold RST button, then MODE toggles LPF (low pass filter), GATE toggles input impedance" I wonder what the LPF cutoff freq is? I am currently doing a noise floor test (connect ref out to input) on my FA2. The initial (12 hour) results are REALLY good... ADEVs at long (1+) tau are in the high E-15 range. I'll post results after I get 24 hours of data. That annoying freq offset of the FA1 is gone. A 12 hour average of the FA2 freq readings is 10,000,000.000 001 Hz (FA2 clocked by a 5071A). ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] FA2 counter
Miy FA2 came in today. A very quick test shows that it works. It does not appear to have the -0.0002 Hz freq measurement bias that the FA1 has. The 0.1 second gate time mode is pretty useless... there appears to be a 300 msec dead time between measurements in 0.1 (and 10 sec) gate time modes so you only get a new reading every 400 msecs. 10 second gate time produces a reading every 10300 msecs. 1 sec gate time outputs readings every 1100 msecs (like the FA1). It auto-detects the presence of an external reference... no way to manually switch between internal and exterrnal references. I have not done any testing on the internal ref or the high freq channel. The screen shows a LPF setting and a 50 ohm setting... no idea if these are switchable there is no documentation. The screen shows the input signal level. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] The effect of centrifugal force on a \n hourglass
https://www.youtube.com/watch?v=7cLjFAADM44 ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Capturing NMEA and TICC timestamp data in time-correlated way?
Lady Heather does measurements on the arrival time of message vs the time encoded in the time message being used and compensates the time code for the offset. It uses a default value that depends upon the receiver type or can use a user specified value. For generic NMEA receivers you should specify the offset (/tsx=offset) since the specific model type cannot be determined. To measure the offset properly, the system time needs to be set accurately. NTP is the best way to do this. The TK keyboard command does the measurement. It calculates an average offset value and a median offset value. Also writes a file with message offset histogram data. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Capturing NMEA and TICC timestamp data in time-correlated way?
Lady Heather should do the job. It supports using a GPS device as the main input device and a TICC/counter as an auxiliary input device (/ei= command line option). Writing a .xml format log file will have all the data. On a TICC you should connect chA to the 1PPS signal (and optionally the divided down 10 MHz to chB. The next version of Lady Heather has a way to write a file with sawtooth corrected counter measurements. Note that there are 12 ways to sawtooth correct the PPS measurement. Only one way will work for a given combination of GPS/counter: add/subtract receiver sawtooth value apply the sawtooth correction to the previous/current/next counter reading apply the correction to the PPS reading or the PPS phase ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] A comparison of the TAPR-TICC and BG7TBL FA1
FA1 noise test was shown here: http://lists.febo.com/pipermail/time-nuts_lists.febo.com/2019-August/097445.html TAPR TICC noise test was shown here: https://www.eevblog.com/forum/metrology/comparing-the-performance-of-17-different-gpsdos/?action=dlattach;attach=591979;image Tom ran my TICC data through Timelab to get pretty plots: http://leapsecond.com/u/sims/gpsdo17/ - > however I think it is interesting to have the noise floor of the test set > because it is a reference absolute value. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] BG7TBL FA1 frequency analyzer
Yes, it should work with Timelab, Stable32, etc. It streams a series of frequency measurements every second out the USB port (it uses a FTDI chip for the USB interface). The data is of the format: " F:0123456789.123456789" (without the quotes) Measurements with a PLL unlock error are preceded by an '*'. I've only seen unlocks when changing the input freq from say 1 MHz to 10 MHz. I get two flagged measurements each time the freq changed. I don't know how small a freq change can cause an unlock. I don't know if Timelab can directly take the output data stream because of the leading "F:". You may need to capture data to a file and edit off the " F:" I also don't know how well it would work for phase noise measurements... it would be no where as good as a TimePod. I am doing some tests to see how well it compares to a TAPR TICC. BTW, my FA1 seems to have a frequency measurement bias of around -0.0002 Hz on a 10 MHz signal. Also, I don't see any temperature related variation in the measurements... air conditioning was swinging the room temp over a 2 degree C span and I saw no traces of it in the results. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] BG7TBL FA1 frequency analyzer
(Hopefully this is not a duplicate post... hotmail has been having issues) The FA1 is a small, USB powered frequency counter. You supply it with a 10 MHz reference and an input frequency of 1 .. 80 MHz. It outputs a text string of the measured frequency every second. They cost around $80 .. $120. Apparently there is a PLL inside... the text string has a "PLL unlock" flag. There is no info on how it works and I have not opened mine up. I did a simple noise test on one where the input and ref clocks were from a Tbolt. It looks like the measurement noise is around +/- 0.0002 Hz. Lady Heather can now read it. Attached is a screen capture of the noise test.___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] GPS Antennas
They work very well. I get the same results as with a $5000 L1/L2 survey antenna. My antenna location is horrible, so there may be some difference with a better location... but I doubt it would be noticeable for most users. I used F9P, F9T, NetRS and Z12 receivers. > Can anyone report back how they worked out? ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Trak Systems 8900 manual
I am adding support to Lady Heather for some Trak Systems GPSDOs.I think I have the 8820. 8821, and 9100 covered. Does anybody know where I can find a Trak Systems 8900 manual? ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] TAPR TIC Upgrade?
Well, I've done that... sort of. I'm still using the TAPR TICC, but have it connected to a PI-3B / official PI touch screen mounted in the excellent SmartiPi case running Lady Heather. Heather can configure the TICC and capture TICC data to a file while simultaneously calculating and plotting the data and ADEV/HDEV/MDEV/TDEV/MTIE of both channels (can do 4 channels with two TICCs). The TICC data can be sent in real-time out a serial or ethernet connection and/or the file can be processed by Timelab or Stable32 or whatever (they do much prettier plots). The PI3 has no problem doing the processing. It remains to be seen if the extra speed and memory of a PI4 will be useful. I've been contemplating doing a front end for the TICC with things like a switchable terminator, polarity selection, variable threshold, internal/external reference oscillator selection, etc. -- > The main benefits would be the bigger RAM on the 4B and the ethernet port. > If you went crazy, you could put a display and buttons on it and have an “all in one” instrument. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Serial or other simple protocols for exchanging time
I would use the NMEA ZDA message. An (easily fixed) issue with Tom's suggestion is the message does not start with a unique character... that can cause issues with syncing to the message (syncing to the end of the previous message has its own issues). Ideally a time message should start/end with unique characters and always be the same length long. Lady Heather does not use a 1PPS input, but has code to read the time encoded in whatever message it uses to drive the display and display time. That code adjusts the message time for any offset between the time in the message and the actual time the message arrives (Heather uses the time-of-arrival of the last byte in the time message). The time offset correction is receiver dependent (it can also be affected by the operating system and serial port/USB interface).Heather uses a default, receiver dependent, time offset or the use can specify the offset (they can be positive or negative) and also has a command for measuring it (provided the OS clock is accurate). ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Is using TAI in Unix/Linux system clocks working in 2019?
Systems that need a leap second free time scale these days seem to be using GPS time instead of TAI. It seems to be rather popular in the financial industry. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] HP OCXO's 10544A and 10811A
I once bought a groups 8 5370A's.Half had 10811's and half had 10544A's. The 10544A's had lower long term drift than the 10811's. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] HP5370A vs B version
Once upon a time, I looked into the front ends of the 5370 counters (mostly 5370A) and found that it was practical to build a replacement using modern chips. I then lost interest in the project when I found an Ebay seller with a lot of 10 pieces of the 5370A chip for dirt cheap (sorry, all are now gone). ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Control and monitor program for Spectracom 8195B
I got in an 8195A and managed to get Heather working with the wonky, very much not computer friendly, Spectracom interface and command set. When you send a command to the device it echoes back the characters. This is very useful for telling what command the device is responding to. But, about half the time, the echoed characters were garbled. Also several response messages came back corrupted. Oh, and occasionally the unit would lock up and require a power cycle to recover. The problem turned out to be that you can't send command strings to the device at computer friendly speeds. You need several milliseconds of delay between each character you send! Anyway, Heather now work with the Spectracom "ageless" oscillators. BTW, for an "ageless" oscillator, these units have a procedure for correcting oscillator aging ;-) --- > The problem with the 8195 is that the serial port software interface was > designed for human interaction with very little regard paid to supporting a > computer monitoring program.___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Most popular NMEA sentence with date and time?
The GPRMC sentence is supported on all the GPS modules that I have. The GPZDA sentence is the best time/date sentence to use if your receiver supports it. It just has date/time info and is usually optimized for the best timing performance. Note that for best accuracy you need to adjust the arrival time of the sentence to the time encoded in the message. For a lot of GPS modules this can be 200-300 msecs. Lady Heather has code for adjusting for the time difference. Different time offsets are automatically selected depending upon the detected receiver type or you can specify the value to use. Most NMEA receivers are rather generic and not easily distinguisable, so the default value may not be the best. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] HP5370A vs B version
The "B" version uses custom hybrid modules for the inputs... and the CH1 and CH2 hybrids are not the same... so you can't swap a CH1 hybrid with a CH2 hybrid. I think the A and B model counters are fairly equivalent in their sensitivity to input damage. It seems to be a lot harder to find replacement parts for the "B". ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Galileo Service Outage Update
Well, they are now saying it was not a timing problem but was caused by bad ephemeris data being broadcast. Processing recorded signals with external ephemeris data yielded proper positions. http://www.navsas.eu/node/611 ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Galileo Service Outage Update
My F9T started tracking Galileo sats at 19:22:10 UTC ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Control and monitor program for Spectracom 8195B
The problem with the 8195 is that the serial port software interface was designed for human interaction with very little regard paid to supporting a computer monitoring program. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Galileo service currently degraded
Lady Heather is open source and has parsers/decoders for just about any receiver you are likely to see... and a few that your aren't.One big issue with binary protocols is handling big/little endian (byte order) issues when reading messages or sending them to the device. You need to be aware of what the system CPU uses and what the receiver uses. > One alternative, if you only need two lines is to write a parser just for > them. There’s not a whole lot to the protocol and the uBlox doc’s are pretty good at describing it. Yes, it’s a binary protocol so there will be a bit of this and that involved. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Galileo service currently degraded
A report that the outage is due to a failure at the Galileo "precise time facility" in Italy. It has all their cesiums and a maser. Hmmm... no backup facility... sounds like a recipe for disaster? Service outage may last over 90 hours. https://insidegnss.com/update-galileo-service-degraded-on-all-satellites-precise-timing-facility-problems-cited/ ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Galileo service currently degraded
The satellite tracking / health info is sent by the receiver. Heather just reports what the receiver is sending. Oh, and the Galileo system status has changed from "degraded" to "service outage". https://www.gsc-europa.eu/system-status/Constellation-Information What is amazing is that I can find no other reports that the system is down. Also how such a long and severe outage could happen. I expect heads will be rolling... -- > What prompts Heather to mark visible satellites as yellow, and not use them? ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Galileo service currently degraded
Not this time... Heather flags unhealthy sats in RED. Sats that are visible but not being used for navigation are flagged in YELLOW. Sats that are actively being used are shown in GREEN and are used to draw the satellite count plot line (CYAN line at the bottom of the plot area). Typically there are a couple of Galileo sats that are always unhealthy. Currently the Galileo sats are all yellow, with a couple shown in red. Yesterday I set the F9T to only use Galileo. The plot line has not shown that it ever actively tracked any Galileo sats in the last 24 hours. > But that is (almost certainly) because they have the sats broadcast "unhealthy" status. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Galileo service currently degraded
It seems to more than a little "degradation". My F9T is seeing and tracking Galileo sats, but is not using the results for navigation... Lady Heather shows all Galileo sats in yellow. Selecting Galileo only, the receiver reports it is attempting to acquire satellites and not producing a navigation solution. Any reports of what kind of screw-up borked the whole Galileo system? ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Advantages of GNSS ???
A big issue with using the sawtooth correction message from a GPS receivers is the issue of just what that sawtooth value is related to and how to apply it to the measured PPS value / phase. I added the ability to Lady Heather to calculate a sawtooth corrected "paper clock" by applying the sawtooth correction message value to the PPS output measured by an external counter like the TAPR TICC. There are around a dozen different combinations of sawtooth value and PPS measurements... only one of which minimizes the PPS error. Do you add or subtract the sawtooth value to the PPS measurement? Do you apply the sawtooth value to the previous/current/next PPS measurement? Do you apply the sawtooth correction to the PPS itself or the accumulated phase of the PPS? I don't think that I have ever seen what to do with the sawtooth value documented in any receiver documentation... Heather has default receiver dependent correction strategies or lets you specify the correction strategy to use. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] A Research Proposal
The message that the TrueTime/Symmetricom FTM-III power line monitor card for the XL/XLi receivers contains: A time error (number of accumulated seconds of error based upon the line frequency) The current frequency error from nominal 50/60 Hz The current measured line frequency (0.001 Hz res). The time that a line freq driven clock would be showing. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Switching 1 pps signal
When I first got my TAPR-TICC one of the first tests that I did with it was to put a coil of RG-58 in the freezer then measured the prop delay as it warmed up. I posted a plot on the list. I didn't have a temp sensor in the coil, though. https://www.febo.com/pipermail/time-nuts/2017-April/104923.html ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] 60Khz received on Wide-band WebSDR
The SD keyboard command in the latest versions of Lady Heather will give you the distance and bearing from your antenna to a specified location along with an estimate of the prop delay and number of ionospheric hops. You can specify the location either as lat/lon or the station name... the command prompt shows a list of supported VLF time stations. -- > For SDR transmitters all over the world... ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Advantages of GNSS ???
Here is screen grab of an F9T tracking GPS/GLONASS/GALILEO/BEIDOU. In the max sig level display the sats that the F9T says do L2 ionospheric corrections are shown in GREEN. Note that the F9T thinks that it is seeing signals from PRNs 192..202 These are the Japanese QZSS sat PRNs. Obviously, these are not visible from the USA. I'm not sure why it thinks it sees signals from these. Perhaps its correlators ate tricked by signals from other sats. It never actually tracks them. --- > On the F9P you have the specific issue of L1 / L2 with older GPS satellites. > The device only does L2C. That cuts the “population” roughly in half.___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] 60 Hz frequency and phase measurement
Attached is a plot of line frequency measurements made by the FTM-III card in a Truetime XL-DC. The FTM-III is meant for measuring line frequency in generating stations, etc. It has a 0.001 Hz resolution. This plot shows a 3 hour window of data, histogram of the data, and ADEV/HDEV/MDEV/TDEV. Also statistics of the data are shown in the lower left corner.___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] 60 Hz frequency and phase measurement
There are numerous devices out there that do non-contact detection of AC voltage in wiring. The wire just has to be live and not connected to a load. Fluke sells a nice one, but I like the GVD-505A from GB instruments because it had a pot to adjust the sensitivity. It has a power switch on the pot... the Fluke has a pushbutton/LED that can be a pain to tell what mode it is in. The non-contact power detection feature is being built into a lot of new multimeters. I also bought a couple of Chinese Fluke style knockoffs... these are dangerous since they don't always respond to conductors carrying current. The circuit seems to be a CMOS gate with a probe wire connected to a gate input. I think there was a biasing circuit / coupling cap on the gate input. Something like that may work for you... ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] 60 Hz frequency and phase measurement
In order to add Truetime XL-DC (and XLi support) to Lady Heather, I bought an XL-DC that happened to have the FTM-III module in it. This module is designed to measure power line frequency for generating stations, etc, It works well, but the minimum integration time is one second. You can specify the integration interval (100,000 seconds (?) max. It also does not measure voltage.Heather can calculate xDEVs and MTIE from the data. I had a nice run captured but lost it. I'll do another run and post it when I am able to do another run. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] accurate time on your pi, the extreme way design
In case you missed the announcement a new Pi 4 has been released. Available in 1GB/2GB/4GB versions with true 1 gbit ethernet and two of the USB ports are USB3. Also two HDMI ports. The CPU clock is 1,5 GHz and the new CPU cores are 2-4 times faster than the current ones. Also, I saw mentioned that the GPIO pins can be config'd for up to 4 serial ports. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Z3801A going into Holdover
A few months ago, my 3801A started doing this. It was tracking sats well (several years ago I had to replace the receiver because it had lots of problems acquiring and tracking sats).I swapped in a replacement 10811 OCXO and that fixed the problem. Apparently the problem with the receiver not tracking sats is usually due to the oscillator on the receiver drifting out of spec. Some of them have an adjustment screw... ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Looking for a HP-58503 display
Nope, I never found a replacement display... still looking. I think the displays showing up on Ebay for various HP equipment are Chinese clones. They even have displays for the 3458A multimenters. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Truetime XLi sat signal levels (dBW to dBc/SNR conversion question)
The 30 dBc refers to the signal level reported by the Ublox. If the Ublox falls below around 30, the Truetime will be reporting -196 dBW. That seems to be the cutoff threshold for its idea of a "good" signal... it does not have a user settable signal level mask My conversion formula works very well over the full range of usable signals and matches what the Ublox is reporting within 1 dB. -- > When you refer to "30 dBc", what is that? Is it the eb/n0 value? If so, with the XLi's behavior as you report it, your scheme would fail over most of the useful signal range. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Truetime XLi sat signal levels (dBW to dBc/SNR conversion question)
I have figured out an empirical formula for mapping between the TrueTime dBW values and the more traditionally reported signal level values. I ran a Ublox F9T and the TrueTime in parallel off the same antenna. By comparing the TrueTime and Ublox sig levels a rather trivial mapping function popped out. Basically you divide the dBW level by the (max dBW)(=145) -min dBW(=196) values) to get a value in the range of 0..1 Multiply that by 50 and add a 3dB fudge factor). The two values match within 1 dB. My XLi uses a Motorola M12 GPS receiver. The XLi reports signal levels less that around 30 dBc as -196 dBW, ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] TICC reference source
If you are using the TICC to measure the time interval between two signals then the reference clock does not need to be all that good (the gooder the better, though). But if you are using the TICC to measure one or two independent sources, then your reference clock should be as good as you can supply. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Truetime XLi sat signal levels (dBW to dBc/SNR conversion question)
I am adding Truetime XL and XLi support to Lady Heather. Pretty much all GPS receivers report sig levels in dBc or SNR type values in the range of around 20 .. 50. The Truetime XLi reports them in dBW with a range of around -196 to -145 dBW). Does anybody know how to convert the dBW values into something more in line with standard dBc or SNR values? The conversion does not need to be exact, it just needs to be reasonable looking... ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] GPS 1PPS, phase lock vs frequency lock, design
How often Lady Heather gets a satellite position report depends upon the receiver type. It can range from every second to once per minute. - > (there seems to be some finite latency in LH's constellation reports, but I'm > not sure how much -- perhaps Mark will comment). ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Bombe clock
Everbody needs one of these... https://www.ebay.co.uk/itm/The-Covert-Bombe-Clock-from-Bad-Dog-Designs-Codebreaking-in-Secret/123775434764 https://www.youtube.com/watch?v=O4ctUqgj7aY ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Truetime XL / XLi question
I am in the process of adding Truetime XL (DC and AK) support to Lady Heather. It looks like I can also support the XLi (does NTP), but the XLi manual has some vague/conflicting info for the output of these commands: F18 - version F72 - faults F73 - alarms Does anybody have an XLi and can capture the serial port output response to these commands? ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Rooftop antenna and splitter
Also, some receivers do a survey every time you power them up. --- > If you move the antennas “far enough” (how far very much depends on the design) the device goes back into survey mode. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] OCXO Question
100 hours is not nearly enough time for the OCXO to stabilize... you need more like 1000+ hours. Here is results of measurements when I put an 8663 into an HP-53132A counter: UTC 8663 mounted on Sweeny DOCXO card in a HP 53132A counter. The 8663 had not been powered up for over 10 years. Below is the frequency drift per day as the 8663 aged in. THe 8663 is spec'd at 1E-10 (1 mHz) per day aging. From past experience, they are capable of much better than that (1E-11 to 1E-12 per day). They seem to be limited in this application by the EFC DAC / VREF performance. The 8663 was mounted on the Gerry Sweeny aftermarket OCXO board for the 531xx counters. For the first 30 days, the board was configured for the 0 .. 10V EFC DAC range. The Sweeny board powers the DAC with +/- 12V which is a bit out of the spec'd minimum +/- 13.5V required for optimum performance on the 0 .. 10V range. The Sweeny OCXO board is based up on the HP design with a couple of nice mods. First it has footprints for several common OCXO modules. Second, it allows the DAC range to be configured for 0 .. 5V, 0 .. 10V, and +/- 5V. The circuit feeds the OCXO output through a differential line driver. The line driver sends the OCXO to the HP counter mother board through a ribbon cable. The motherboard makes the OCXO output available on a BNC on the counter back panel. Checking the ADEVs of the raw OCXO outout and the counter output shows that the 53132A degrades the DOCXO output by around 1.5E-12 (raw DOCXO value around 5.1E-12 at 200 seconds, counter 10 MHz output BNC around 6.5E-12) For the first 30 days the EFC DAC reading was recorded and the HP53132A was then auto-cal'd and the new EFC DAC output was recorded. (The DAC readings for the first 10 days were lost when a momentary power failue occured and the system was not shut down cleanly). The initial 30 day run was done with the Sweeny board DAC configured for the 0 .. 10V range. Given the DOCXO EFC sensitivity (around 0.75 V / Hz) and the 12-bit DAC, the minimum auto-cal resolution is 0.002 Hz. Several auto-cal cycles were performed each morning until one was within 0.001 Hz. DAC readings were made by a Tektronix DMM914 4.5 digit DMM, not the best tool for the task, but it was available. drift (Hz/day)DAC (after cal -> 24 hrs later) day 1:.298000 Hz day 2:.057000 Hz day 3:.033000 Hz day 4:.022000 Hz day 5:.017000 Hz day 6:.011800 Hz day 7:.009640 Hz 4.471V day 8:.008400 Hz 4.458V day 9:.006380 Hz 4.451V day 10: .003880 Hz 4.443V day 11: .002840 Hz 4.446V -> 4.438V // power glitch caused reset day 12: .003470 Hz 4.437V -> 4.437V day 13: .002100 Hz 4.432V -> 4.433V day 14: .001590 Hz 4.430V -> 4.430V day 15: .001380 Hz 4.426V -> 4.428V day 16: .001660 Hz 4.424V -> 4.426V day 17: .000526 Hz 4.422V -> 4.423V day 19: .000284 Hz 4.421V -> 4.423V day 20: .38 Hz 4.423V -> 4.424V day 21: .001019 Hz 4.420V -> 4.420V day 22: .001350 Hz 4.417V -> 4.418V day 23: .000402 Hz 4.417V -> 4.417V day 24: .000953 Hz 4.418V -> 4.419V day 25: .000304 Hz 4.417V -> 4.416V day 26: -.000441 Hz 4.417V -> 4.418V day 27: .000214 Hz 4.415V -> 4.415V day 28: .000517 Hz 4.415V -> 4.416V day 29: -.000998 Hz 4.415V -> 4.415V day 30: .001300 Hz 4.415V -> 4.414V day 31: .000423 Hz Powered down, replaced 53132A fan, changed DAC range to 0 .. 5V, and the 53132A was put back into case (hence no more DAC readings). The 0 .. 5V DAC range reduced the auto-cal minimum step size to 0.001 Hz. Hopefully it should also improve the DAC stability. Warmup frequency error after power up: 1 Hz - 3m 0.1 Hz - 3m 25s 0.01 Hz - 5m 45s 0.001 Hz - 6m 15s After 24 hours the unit was auto-cal'd once and left alone. The frequency error for the next week: day 32: .000152 Hz (0.9 Hz/day for last 18 hours) day 33: -.000825 Hz day 34: -.000730 Hz day 35: -.000287 Hz day 36: -.000144 Hz day 37: -.86 Hz day 38: -.83 Hz ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] True position unlocking
Unless you have a really crappy antenna setup, I doubt it is a signal level problem. These receivers do like to do the "holdover" thing. No telling if those are real holdovers, though... no documentation. It could be that the device is going into some house-keeping mode... who knows? Also try to force a self-survey (SS keyboard command). ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] GPS week rollover grounds airplanes
Apparently the rollover grounded some airplanes... oops... https://arstechnica.com/information-technology/2019/04/gps-rollover-apparently-cause-of-multiple-flight-delays-groundings/ ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Navsync CW25 undocumented messages
After upgrading the firmware in my CW25, I took a look at the new firmware .bin file and found what looks like some undocumented / new messages and parameters. I sent it requests for the unknown parameters and got back these strings: $PRTHR,PPSO,0,0,10*51 $PRTHR,MCNO,30*40 $PRTHR,IDNO,00*40 Does anybody know what the PPSO, MCNO, and IDNO parameters are? The PPSO one sounds interesting... perhaps a PPS offset or cable delay setting? Maybe MCNO is a signal level mask? It returns 30, but my receiver is tracking sats with quite a bit lower signal levels. I also found references to the following messages: $POLYD $POLYN $POLYX $GPRMX (?) I tried enabling them but got no response. The $POLYx messages are proprietary Navsync NMEA format messages. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Navsync CW25 rollover
The Navsync CW25 crapped its pants when rollover occurred. It (and a lot of other Navsync devices) have a known firmware bug where they stop tracking sats if the week number is 0. Sure enough, at zero hour, all the sats disappeared. Conner Winfield has firmware updates for the problem receivers. The updates are in .rar format files that require winrar v5.x to unpack. See: http://www.conwin.com/pdfs/gps_week_rollover.pdf So, I uploaded the new firmware... which went well. The new firmware does enable the ability to set the satellite elevation mask.At first the new firmware was still not tracking satellites. It took 10 hours before it started working. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Rollover : Thunderbolt
Thunderbolts have a rollover date based upon the firmware build date. That delays the week rollover. They went into rollover mode around May-June of 2017. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Navsync CW25 rollover
I recently got in a Navsync CW25 based receiver and added support for it to Lady Heather. I found some info that says current firmware will be affected by the rollover... in a major way! When the week reaches 0, it stops tracking sats for the whole week. Conner-Winfield has updated firmware for the affected devices. The updates are in a .rar file that requires winrar 5.xx to extract. The CW25 is the only receiver that I know of that actually stops working because of rollover. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Lars GPSDO
On a real simple GPSDO that I built, I drove the PWM into a 2N700x fet, pulled the FET output up with the OCXO VREF / resistor, and added a RC filter. Seemed to work rather well. The OCXO VREF was around 7V. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] NAVICOM RCGD-M GPSDO
I got in the GPSDO from China. It looks nice, but I have not tried firing it up yet. I have no other info on this GPSDO. Here is what the seller has found out. This GPSDO has two 10 MHz SMA connectors and a MMCX (?) antenna connector. It has a 2007 date etched on a PCB. I suspect some of those pins (probably on CON4) has a "management" interface where you can config and monitor the GPSDO, but it does not send data unless polled. Whatever language it speaks is unknown... no documentation. My best guess is it may be like the TL1 stuff like the Star4 and NEC GPSDOs... maybe on CON4 15 .. 18. Signal connectors for NAVICOM RCGD-M GPSDO: CON5: PIN1: 10MHz output, LVTTL PIN2-6,10: Unknown PIN7-8,11,15: should be output, connect to FPGA, LVTTL PIN13,16-18: should be input, connect to FPGA, LVTTL PIN12,14: 39.32MHz clock signal output,LVTTL PIN9: 1PPS output PIN19-20: power ground CON4: PIN1: 1Hz 50% duty cycle output PIN2： 1Hz 23% duty cycle output PIN3-4，6-12: unknown PIN5: TXD(TOD?) PIN13-14: +12V 1A power supply input PIN15: should be output, connect to FPGA, LVTTL PIN16-18: should be input, connect to FPGA, LVTTL PIN19-20: GND, power ground CON8 (connects two boards together) PIN7: 1PPS signal from GPS receiver PIN9: RXD signal from GPS receiver, LVTTL PIN11: TXD signal from GPS receiver, LVTTL, Baud rate 9600, 8-bits, no parity connect the TXD to PC via RS232<-> UART Adapter, and we have been used Lady Heather that configures as MOTO receiver to monitor the status of this GPSDO. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] GPS week rollover
I doubt that any GPS receivers will be newly affected on April 6. Some very early receivers were hit on the first GPS rollover, but those made since then usually have a 1024 week compensation built in based upon the firmware creation date. Those rollover 1024 weeks from that date and start sending incorrect dates at other places in the 1024 week cycle. Some receivers even let you force the rollover week. > I have a Z3816A that’s showing a yellow “ro” next to the date in LH and is 18 > seconds ahead of a Motorola 12 channel If Lady Heather sees a date earlier than a set year (currently 2017), it assumes the GPS device has rollover issues and adds 1024 weeks to correct the date and shows the "ro" flag. As far as the 18 second time difference, one of the devices is configured to show GPS time and the other is set for UTC time. At the top right corner of the screen it should say either "UTC time OK" or "GPS time OK" (as long as the device has a valid time). The TG and TU commands can switch between GPS and UTC time displays. Some receivers have firmware commands to switch between the two. For the others, Heather does the conversion in software using the "UTC offset" (i.e. leapsecond count) value. Many receivers send this offset. If it does not, the user can set the value. And if no value is available Heather makes a best guess as to what the value might be (and shows it in RED). The guessed value is rather prone to errors, but is better than nothing. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] NAVICOM RCGD-M GPSDO
I recently picked up a NAVICOM RCGD-M GPSDO off of Ebay. Does anybody have any info on these? One version seems to have a Furuno GT08031, another seller show Lady Heather monitoring a Motorola 8 channel GPS, ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
