Re: [time-nuts] Trimble 46865-00-BM
I have been offered what appears to be a Trimble GPSDO board. The model number is 46865-00-BM. From the photos, the board appears to be about the same size and layout as my NTBW50AA and includes a Trimble STP2254 10 MHz TCXO module, a USB port, and the same type of backplane connectors as the Nortel unit. I cannot find anything about it on the web even to figure out what it was originally used for. Is anyone on the list familiar enough with this particular board to point me to some reference information? Thank you, Bob, K0BT ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Ublox neo-7M GPS
Be patient as soon as we have finished rollout of the FE 5680A and FE 405 B GPSDO I will be off the list. Bert Kehren In a message dated 8/19/2014 9:31:50 P.M. Eastern Daylight Time, csteinm...@yandex.com writes: Bert wrote: I guess time nuts like to talk about it but not fix it. Will you PLEASE quit beating this tired old drum? All of us know this is your opinion, although many of us have other explanations for the phenomena you think it explains. We do not need you to repeat it every time you post, and it is offensive. Best regards, Charles ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] more worm code
// worm: 32 diametral pitch (# of teeth per inch of diameter on pitch circle)
// 32 inch = 32/25.4 = 1.26 DP (in mm)
// nTeeth = DP * 2 * r;
// Create enveloping worm gear / pinion gear by incrementally
// subtracting off parts of the matching worm screw
// very slow to compute full gear with reasonable detail / smoothness
// 2014-08-19 J.Beale
//
// https://github.com/elmom/MCAD/blob/master/involute_gears.scad
//
https://github.com/syvwlch/Thingiverse-Projects/blob/master/Threaded%20Library/Thread_Library.scad
use MCAD/Thread_Library.scad
use MCAD/involute_gears.scad
eps = 0.05; // Epsilon = a small number
numberTeeth=40; // number of teeth on worm gear (pinion gear)
pitchRadius=40; // pitch radius of worm gear (pinion gear)
gearSegAngle = 10; // toothed part of gear segment (360 = full gear)
length=20; // length of worm screw
radius=10; // radius of worm screw
pi = 3.1415926535897932384626433832795;
pitch = 2*pi*pitchRadius/numberTeeth;
angle=360*$t;
offset=7.5;
distance=radius+pitchRadius+0.0*pitch;
GearThick = 10; // thickness of gear
xoff = -GearThick/2;
rAngle = 360/numberTeeth;
wAoff = -50; // initial angular offset of worm screw
// ===
// == QUALITY FACTOR (higher = slower, better) ==
// ===
cSteps = 17; // rotational carving steps for worm: larger = smoother surf.
StepsPerTurn = cSteps+3; // facets around worm screw: larger = smoother
// ===
EngageDepth = pitch*0.3; // carving out gear from blank
// echo(EngageDepth);
// worm(wA = 10);
module worm(wA = 0) {
translate([0,distance-EngageDepth,0.2-length/2])
rotate([0,0,180+wA])
trapezoidThread(
length=length, // axial length of the threaded rod
pitch=pitch, // axial distance from crest to crest
pitchRadius=radius, // radial distance from center to mid-profile
threadHeightToPitch=0.5, // ratio between the height of the profile and the
pitch
// std value for Acme or metric lead screw is 0.5
profileRatio=0.5, // ratio between the lengths of the raised part of the
profile and the pitch
// std value for Acme or metric lead screw is 0.5
threadAngle=14.5, // angle between the two faces of the thread
// std value for Acme is 29 or for metric lead screw is 30
RH=true, // true/false the thread winds clockwise looking along shaft,
i.e.follows the Right Hand Rule
clearance=0.0, // radial clearance, normalized to thread height
backlash=0.1, // axial clearance, normalized to pitch
stepsPerTurn=StepsPerTurn // number of slices to create per turn
);
} // end module worm()
module myToothBlank() {
translate([-GearThick/2,pitchRadius-8,0])
rotate([360/(numberTeeth*2),0,0])
cube([GearThick,pitch*1.5,pitch]);
}
module oneTooth() {
difference() {
myToothBlank(); // blank to form tooth via CSG subtraction
worm(wA = wAoff); // worm screw
for(f = [-.1:(1.0/cSteps):1.1]) { // computational machining (gear hobbing)
rotate([rAngle*f,0,0]) worm(wA = (360*f)+wAoff);
}
}
} // end module oneTooth()
// full gear = oneTooth * numberTeeth
// deg = 360.0/numberTeeth;
module gearSegment(segAngle = 90) {
for(deg = [0:360.0/numberTeeth:segAngle]) {
rotate([deg,0,0]) oneTooth();
}
}
module hub(ID = 5) {
difference() {
rotate([0,90,0]) translate([0,0,-GearThick/2])
cylinder(r=pitchRadius-(radius/2),h=GearThick,$fn=60);
rotate([0,90,0]) translate([0,0,-eps-GearThick/2])
cylinder(r=ID/2,h=GearThick+2*eps,$fn=20);
}
}
gearSegment(segAngle=gearSegAngle); // full gear = segmentAngle = 360
hub(ID = 8); // inner part of gear wheel with ID boresize
// worm();
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Re: [time-nuts] Cutler NAA on 24.0kHz....
NAA -50 dbm (1 MV) using a mini-whip. -60 dbm on the k9ay loop. Mini-whip is full of surprises. 73, Bill, WA2DVU Cape May, NJ -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of paul swed Sent: Tuesday, August 19, 2014 9:51 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Cutler NAA on 24.0kHz Did measure NAA near Boston 8000uv using a dipole for 80 meters. Looking at various vlf receivers it looks like a LPF or maybe a BPF filter to a ne602 mixer followed by a tl081opamp LPF makes a direct conversion receiver. Then hit the tracor d-msk-r. Regards Paul WB8TSL On Mon, Aug 18, 2014 at 2:34 PM, Charles Steinmetz csteinm...@yandex.com wrote: Paul wrote: Nat Semi App Note 72 page 18, par. 6.4 shows the configuration for bandpass active filter. This matches the last LM3900 stage, so you would seem to be correct. The shift in filter frequency for 200bps is because the higher modulation rate results in a greater frequency shift. It's like 50hz instead of the 25hz of the 100bps rate. Robert wrote: It's simple, but not obvious. The LM3900 is a Norton amplifier, and while it has differential inputs they are current driven. * * * Both the upper amplifier and the second lower amplifier have 1M feedback resistors, and + inputs fed 10V by 1M bias resistors. That would bias the output at near the supply rail, turning these stages into something like half-wave rectifiers. Since the first lower stage has a 2M bias resistor it idles at about half supply, and behaves as a simple inverter. * * * combining the two outputs produces a negative going full wave rectification of the signal. The fourth LM3900 stage looks like an inverting bandpass filter, but I'd have to dig out some reference books to determine its behavior in more detail. As f or the 100-200 switch I'm confused, why would the bandpass frequency be lowered for the higher modulation rate? The circuit as a whole operates as a frequency doubler using full-wave rectification and filtering. The rx LO is 100Hz below the nominal carrier frequency, so in normal (non-MSK) mode, the IF frequency is 100Hz. Referring to the MSK addendum, a received 200 baud MSK signal is 50Hz below nominal, and a 100 baud MSK signal is 25Hz below nominal. With the LO 100 Hz below nominal, this makes the IF frequency 50Hz when receiving a 200 baud MSK signal, and 75 Hz when receiving a 100 baud MSK signal. After doubling, these become 100 Hz (200 baud) and 150 Hz (100 baud), so the BPF is switchable between 100Hz and 150Hz. They used a FET to chop the 150Hz (100 baud) signal with a 50Hz square wave. I can't say I'm impressed with the design, even for the era. The whole instrument is built mostly with LM3900s, which makes it thousands (maybe even millions) of times noisier than it would be if it had been properly designed with standard op-amps. It may work more or less, but it's a fugly way to get there. There are other questionable choices (like the FET chopper, an overall design that depends on lots of one-shots, etc.). The designers knew about the LM301 (there is one in the unit), so there was really no excuse for using LM3900s. Yeah, the 301 was more expensive -- but this was supposed to be a state-of-the-art measuring device for characterizing good OCXOs down to PPB or below. I simulated the MSK board in LTspice. Let me know (OFFLIST ONLY, please) if you would like the files to play with (662kB ZIP file). (Note that these won't do you any good if you're not an LTspice user.) Again, please do not clutter the list with requests for files -- OFFLIST ONLY, please (check your headers carefully before you hit Send). Best regards, Charles ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/ mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. --- This email is free from viruses and malware because avast! Antivirus protection is active. http://www.avast.com ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] MSK option for Fluke 207 and Tracor 599
Dear Sirs, I`m looking for a MSK option for the Fluke 207 and/or the Tracor 599 receivers. Is there a circuit diagramm? Any help would be very much appreciated. Ludwig oe1lpw --- Diese E-Mail ist frei von Viren und Malware, denn der avast! Antivirus Schutz ist aktiv. http://www.avast.com ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] MSK option for Fluke 207 and Tracor 599
I do not believe that there is. I think it may be due to the timing of msk introduction and the end of life of the products/companies. The tracor demonstrates a clever way to get rid of MSK but requires a 100 Hz IF. So far for me at least its unclear how you would re-use the tracor trick on the 2.5KHz IFs of the 207 and 599. Yes you could down convert 2.5Khz to 100 Hz. Messy and there is additional things that would need to happen to make the radios work. I have both by the way. Regards Paul WB8TSL On Wed, Aug 20, 2014 at 1:04 PM, oe1lpw oe1...@telekabel.at wrote: Dear Sirs, I`m looking for a MSK option for the Fluke 207 and/or the Tracor 599 receivers. Is there a circuit diagramm? Any help would be very much appreciated. Ludwig oe1lpw --- Diese E-Mail ist frei von Viren und Malware, denn der avast! Antivirus Schutz ist aktiv. http://www.avast.com ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/ mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] HP Z3805A
My Z3805A has the trouble that the date on SATSTAT is not changed by command (:GPS:INIT:DATE (yr,mo,day)). Anyone can advice me for the above. From: komnet2k Tokyo JAPAN ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Ublox neo-7M GPS
On 19/08/2014 16:11, Ed Palmer wrote: Does anyone have a neo-7M and an HP 5371A or a 5372A Analyzer? Use the Histogram Time Interval function to measure a block of samples. That will show the length of the samples with a resolution of 200 ps. That's what I did a couple of years ago when I analyzed the Navsync CW-12 with the old and new firmware. FWIW, I just had a look at the timepulse on a NEO-7M. I configured it to 10MHz, 50:50 duty cycle when locked, disabled when out of lock. I don't have any of those Analyzers so I used an HP 54615B digital scope. The period of the majority of cycles was 104ns with 'random' cycles being 84ns. I did not observe any other cycle periods. I don't know how accurate the time measurements are on the scope, but it looks like the timing is derived from an approx 48MHz clock, and the timing phase/frequency adjusted by periodically deleting 48MHz clock cycles. Although I said random, I couldn't make any observations as to the statistics of the short and long cycles or their distribution - I guess I'll have to write some software for my STM32F4 discovery board for that. If I get time, I'll do the same with a Reyax RYN25AI receiver which has a UBLOX MAX-7C module. Tony ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] HP Z3805A
komne...@yahoo.co.jp said: My Z3805A has the trouble that the date on SATSTAT is not changed by command (:GPS:INIT:DATE (yr,mo,day)). Anyone can advice me for the above. It may only work if you send the date before it locks to GPS. That is you need to do something like: power off disconnect antenna power on set date (verify on status page??) connect antenna -- These are my opinions. I hate spam. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] MH370 Doppler
The L Band uplink was reported to be transmitting at around 1.6435/ghz. / Assuming, we actually knew what the tolerance of the OCXO (If it is an OCXO) was under the environment of the mishap, and assuming it /was/ 10ppm for example. The error would be (1,650 X1,000,000) * 10ppm or _16,500 hz_. I think we can discount the error being that large, but could still rationalize it being a significant portion of the reported BFO value./ / Also the ground track is unknown, they are attempting to reconstruct the ground track from the BFO (Burst Frequency Offset Doppler) and from the BTO (timing pings) the BTO supposedly offers range information, hence the concentric rings corresponding to pings._ _ _Chris Alb__ertson wrote:_ The total Doppler in this case is on the order of 100 Hz. The tiny frequency shifts of an out of spec OCXO is just to small to measure. The data says at UTC 18:30 the shift was in the mid range and was about 175Hz. Assume the OCXO drifts 10 parts per million. That is a lot for an OCXO. But maybe the effect is only about 50 feet on the ground. The OCXO error of even 1E-5 is just not very important as it does not move the aircrafts ground track enough to matter. -- Joe Leikhim Leikhim and Associates Communications Consultants Oviedo, Florida jleik...@leikhim.com 407-982-0446 WWW.LEIKHIM.COM ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Ublox neo-7M GPS
Hi Tony, that's consistent with what I remember. Do you have the capability to count the number of 10MHz pulses per second to see if it is phase-coherent with the UTC 1PPS pulse? I am thinking that the software may be using statistics to approximate 10 million cycles per second, which would mean they may or may not be exactly 10 million cycles.. thanks, Said In a message dated 8/20/2014 11:07:59 Pacific Daylight Time, tn...@toneh.demon.co.uk writes: On 19/08/2014 16:11, Ed Palmer wrote: Does anyone have a neo-7M and an HP 5371A or a 5372A Analyzer? Use the Histogram Time Interval function to measure a block of samples. That will show the length of the samples with a resolution of 200 ps. That's what I did a couple of years ago when I analyzed the Navsync CW-12 with the old and new firmware. FWIW, I just had a look at the timepulse on a NEO-7M. I configured it to 10MHz, 50:50 duty cycle when locked, disabled when out of lock. I don't have any of those Analyzers so I used an HP 54615B digital scope. The period of the majority of cycles was 104ns with 'random' cycles being 84ns. I did not observe any other cycle periods. I don't know how accurate the time measurements are on the scope, but it looks like the timing is derived from an approx 48MHz clock, and the timing phase/frequency adjusted by periodically deleting 48MHz clock cycles. Although I said random, I couldn't make any observations as to the statistics of the short and long cycles or their distribution - I guess I'll have to write some software for my STM32F4 discovery board for that. If I get time, I'll do the same with a Reyax RYN25AI receiver which has a UBLOX MAX-7C module. Tony ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] MH370 Doppler
Yes, that is what they are doing. A given Doppler shift corresponds to a certain ring on the Earth's surface. Each Hertz of Soppler shift corresponds to a certain number of miles on the radius of the ring. At 1.6GHz one part per billion is 1.6Hz.175Hz of shift gives something like a 2,400 mile radius ring. On Wed, Aug 20, 2014 at 8:47 AM, Joe Leikhim jleik...@leikhim.com wrote: The L Band uplink was reported to be transmitting at around 1.6435/ghz. / Assuming, we actually knew what the tolerance of the OCXO (If it is an OCXO) was under the environment of the mishap, and assuming it /was/ 10ppm for example. The error would be (1,650 X1,000,000) * 10ppm or _16,500 hz_. I think we can discount the error being that large, but could still rationalize it being a significant portion of the reported BFO value./ / Also the ground track is unknown, they are attempting to reconstruct the ground track from the BFO (Burst Frequency Offset Doppler) and from the BTO (timing pings) the BTO supposedly offers range information, hence the concentric rings corresponding to pings._ _ _Chris Alb__ertson wrote:_ The total Doppler in this case is on the order of 100 Hz. The tiny frequency shifts of an out of spec OCXO is just to small to measure. The data says at UTC 18:30 the shift was in the mid range and was about 175Hz. Assume the OCXO drifts 10 parts per million. That is a lot for an OCXO. But maybe the effect is only about 50 feet on the ground. The OCXO error of even 1E-5 is just not very important as it does not move the aircrafts ground track enough to matter. -- Joe Leikhim Leikhim and Associates Communications Consultants Oviedo, Florida jleik...@leikhim.com 407-982-0446 WWW.LEIKHIM.COM ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. -- Chris Albertson Redondo Beach, California ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Ublox neo-7M GPS
Thanks, Tony. That's good info. So now we've confirmed that the neo-7M has an NCO and it appears that it's resolution is 20 ns. The data sheet shows the 'Accuracy of time pulse signal' is 30 ns RMS and 60 ns for 99%, but it isn't clear whether they're referring to jitter or error with respect to GPS seconds. The original question was whether the neo-7M would make a good GPSDO. As we've seen, the answer is no. Cheap, yes. Good, no. Setting aside the NCO issue, the neo-7M isn't a timing receiver, it's a navigation receiver. That limits it's performance in many ways. Ublox sells timing receivers, but they're still NCO-based. They're also significantly more expensive than the navigation receivers. One example is Synergy Systems' SSR-6Tr if it's still available. It was announced, and discussed on this list, in 2012 but it still isn't listed on their web site so I don't know what it's status is. It's based on the LEA-6T timing receiver which has a spec for the 1 PPS is 'within 15 ns to GPS/UTC (1 sigma)'. That can be further reduced with some extra work. If the performance of an NCO-based unit isn't enough, you might want to consider Jackson Labs GPSTCXO which is a real GPSDO. More expensive than the NCO-based units, but you get what you pay for. No, I'm not associated with Synergy or Jackson labs. So Graham, if you survived the firestorm started by your simple question, are you any wiser? Ed On 8/20/2014 7:56 PM, Tony wrote: On 19/08/2014 16:11, Ed Palmer wrote: Does anyone have a neo-7M and an HP 5371A or a 5372A Analyzer? Use the Histogram Time Interval function to measure a block of samples. That will show the length of the samples with a resolution of 200 ps. That's what I did a couple of years ago when I analyzed the Navsync CW-12 with the old and new firmware. FWIW, I just had a look at the timepulse on a NEO-7M. I configured it to 10MHz, 50:50 duty cycle when locked, disabled when out of lock. I don't have any of those Analyzers so I used an HP 54615B digital scope. The period of the majority of cycles was 104ns with 'random' cycles being 84ns. I did not observe any other cycle periods. I don't know how accurate the time measurements are on the scope, but it looks like the timing is derived from an approx 48MHz clock, and the timing phase/frequency adjusted by periodically deleting 48MHz clock cycles. Although I said random, I couldn't make any observations as to the statistics of the short and long cycles or their distribution - I guess I'll have to write some software for my STM32F4 discovery board for that. If I get time, I'll do the same with a Reyax RYN25AI receiver which has a UBLOX MAX-7C module. Tony ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
