Re: [time-nuts] OCXO sensitive to gravity
Or at least that provides a reason to question the "inherited design".. On 8/15/09 5:32 PM, "saidj...@aol.com" wrote: > Hi James, > > the kind of experience that makes one a better engineer :) > > bye, > Said > > > In a message dated 8/15/2009 14:35:41 Pacific Daylight Time, > james.p@jpl.nasa.gov writes: > > > Yes.. In our case, though, I think the microphonics were from movement of > the cavity lid, which wasn't very rigid. The lid moved, moving the tuning > screw, which moved the little tuning plate suspended over the ceramic puck. > It was a prototype to be sure, so the production item wouldn't be as bad, > but that sort of thing convinced me that anything we could do to reduce the > amount of touch labor needed was to the better. > > > ___ > 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] RF absorber
a few have asked about the absorber I have the sheets are roughly 23.5 x 23.5 inches and about 1/8 inch thick they weight approx 8.4 lbs each they were packed between 40 and 45 sheets per wooden create and there were 6 creates The label from one of the sheets reads PLESSEY MICROWAVE MATERIALS P.O. BOX 85600 SAN DIAGO, CALIFORNIA 92128 619-571-7715 MICROWAVE ABSORBER PN 9433A TN 504 PS 3055391B WO 3971 MX 051302DATE 5-20-85 and below that two qc stamps the cost of the tube + shipping is all I want. It would be nice that the stuff does not end in the land fill. So if interested, email me with ABSORBER in the subject and I will at least keep a list and go from there. I am very busy right now but I will see what I can do. -pete ___ 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] OCXO sensitive to gravity
Hi Rick, wonder if the operators needed their hearing calibrated after long exposures to that :) A long time ago I designed and built a 1KHz ultra-low-distortion signal generator using the original H/P design (Wien bridge(?) with a small lamp for amplitude stability). That lamp is a great seismic sensor. bye, Said In a message dated 8/15/2009 13:19:28 Pacific Daylight Time, rich...@karlquist.com writes: A well used trick with the HP608 signal generator, which did not have frequency modulation, was to mount a speaker on the side of the case and drive it with 1 kHz to generate FM using microphonics. It supposedly worked quite well and could even be calibrated. Rick Karlquist N6RK ___ 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] OCXO sensitive to gravity
Hi James, the kind of experience that makes one a better engineer :) bye, Said In a message dated 8/15/2009 14:35:41 Pacific Daylight Time, james.p@jpl.nasa.gov writes: Yes.. In our case, though, I think the microphonics were from movement of the cavity lid, which wasn't very rigid. The lid moved, moving the tuning screw, which moved the little tuning plate suspended over the ceramic puck. It was a prototype to be sure, so the production item wouldn't be as bad, but that sort of thing convinced me that anything we could do to reduce the amount of touch labor needed was to the better. ___ 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] Best way for generating 8994.03 MHz from 2899.00042272.....MHz?
> and that brings him to about 55 MHz. To generate that 55 MHz he has > several options: - Cascading two DDS chips to get many bits of > frequency resolution and leave the thing in open loop. I don't like > the absence of feedback in this option, Why do you want feedback for a DDS? It's not a PLL with a bunch of analog parts that needs tweaking to get the right output. On a DDS, if you know the input clock, you can predict exactly what will come out, spurs and all. -- There is a layer of math associated with a DDS that I don't understand. Suppose you have 10 MHz input clock and a 20 bit DDS. If you want 1 KHz out, your choices are 1001.359 and 991.822 (assuming I did the math right) 10 MHz to 1 KHz is a simple divide by 1. But a 20 bit DDS can't do that cleanly. On the other hand, if you use decimal arithmetic rather than binary, you get 1 KHz exactly. I think that can be generalized to dividing by any X rather than 2^N or 10^M. So you can make an exact output for any Fin*P/Q where P << Q. I think that gives you the same frequencies as a traditional PLL with dividers on the input and feedback. But you don't get to filter the analog control voltage and you only get the frequencies where the divider on the input frequency is bigger than the divider in the feedback path. -- Back to the initial question: > A colleague from a Free Electron Laser lab has the following problem: > he needs to make a frequency to use as an X-band LO that is > *exactly*8994.03 MHz (3*2998.01 MHz) and it *must* be locked to his > S-band LO which is exactly 2998.01*732/757 MHz (2899.00042272.MHz). > He intends to multiply his S-LO by 3 and that gets him close, about > 297 MHz away. Then he can add another frequency he has(that is locked > to his S-LO) of 241.6. MHz (2998.01*61/757 MHz to be exact) and > that brings him to about 55 MHz. To generate that 55 MHz he has > several options: Dropping out the multiply by 2998.01 and divide by 757 we want 3*757 = 2271 we have 3*732 = 2196 difference is 75 we have 61 difference is 14 So "about 55" is 2998.01*14 /757 or 55.445 I assume he can use whatever technology he used to get 297 MHz, just plug in 14 rather than 61. Or run a 14/61 PLL from the 241.6 clock. But I'm missing a couple of key ideas. How does one build a PLL at 3 GHz or 9 GHz? What does "exact" mean in this context? Is that something to do with phase noise, or does it just mean we can't round off the numbers? Is there actually a 2998.01 clock? If so, why is a simple 3x PLL not the right answer? Perhaps the true master clock is actually S-LO at 2998.01*732/757, and it's just written that way to make all the ratios visible for reasons that are important when you look at some other part of the problem. -- These are my opinions, not necessarily my employer's. 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] OCXO sensitive to gravity
Yes, using a quartz resonator to sense the force and other to provide temperature compensation. I remember that it was a very sensitive device, and althought several kilobucks about fifteen years ago, it was not prohibitive. That unit was a of the type that appears in the drawing 'high pressure design' here http://www.paroscientific.com/pdf/dqadvantage.pdf since it was intended to work inmersed in the sea. Regards, Javier J. Forster escribió: Oops. It looks like they sense the force from the Bourdon tube, rather than the displacement. -John === Yes... it was not cheap, exactly :) It was from this company: http://www.paroscientific.com/ Regards, Javier J. Forster escribió: Oh, I know there are quartz transducers like accelerometers, pressure and force gages, etc. from companies like Endevco, Kiag/Krystal, and others. But in my experience they are lab instruments costing a bundle. The airbag sensors are cheap... likely a buck or twp. Hence the use of silicon. Best, -John === J. Forster escribió: As you feel your heart beat, google for Quartz Pressure Sensor Again, I think these are semiconductor sensors. Yes, but there are also quartz pressure sensors. Long time ago I used a equipment to measure water columns (and hence sea waves height) that used a quartz-based pressure sensor. It was a very sensitive equipment. Regards, Javier -- Javier HerreroEMAIL: jherr...@hvsistemas.com HV Sistemas S.L. PHONE: +34 949 336 806 Los Charcones, 17AFAX: +34 949 336 792 19170 El Casar - Guadalajara - Spain WEB: http://www.hvsistemas.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. -- Javier HerreroEMAIL: jherr...@hvsistemas.com HV Sistemas S.L. PHONE: +34 949 336 806 Los Charcones, 17AFAX: +34 949 336 792 19170 El Casar - Guadalajara - Spain WEB: http://www.hvsistemas.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. -- Javier HerreroEMAIL: jherr...@hvsistemas.com HV Sistemas S.L. PHONE: +34 949 336 806 Los Charcones, 17AFAX: +34 949 336 792 19170 El Casar - Guadalajara - Spain WEB: http://www.hvsistemas.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] Difference in GPS antennas
Lux, Jim (337C) wrote: On 8/15/09 3:25 PM, "Chuck Harris" wrote: Lux, Jim (337C) wrote: On 8/15/09 8:27 AM, "Magnus Danielson" wrote: If you're near a harbor with fishing boats, you'll see plenty of quad helices about a half a meter in overall height, used for VHF Weather satellite reception. They're also used on spacecraft (Mars Science Lander, Mars Reconnaissance Orbiter, and Phoenix all have UHF quad helix antennas, I think, for about 400 MHz) Not used by the fishing vesels near me... Really? Practically all the fishing boats (mostly squid) boats going out from Ventura Harbor (in Southern California) have big ol' quad helix antennas up on the cross bar (as well as the usual HF SSB and VHF whips and the radar). Maybe it's a regional preference thing (or folks are going to the 1.6 GHz band or something). Haven't all of the VHF weather satellites been decommissioned? Could be. I suspect that those antennas have been up on those boats for decades. I think this explains fairly well why I haven't seen them. VHF weather satellite reception has not been necessary for most fishing vesels on the Baltic sea, especially those doing near coast fishing. National weather services have sufficed for many decades, and before that looking out the window and a barometer did alot anyway for the fishermens I know. Cheers, Magnus ___ 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] Difference in GPS antennas
On Sat, Aug 15, 2009 at 03:34:29PM -0700, Lux, Jim (337C) wrote: > > Haven't all of the VHF weather satellites been decommissioned? > > Could be. I suspect that those antennas have been up on those boats for > decades. Hardly, there are still the old analog APT satellites in operation plus at least one using digital (LRIT) > > > ___ > 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. -- Dave Emery N1PRE/AE, d...@dieconsulting.com DIE Consulting, Weston, Mass 02493 "An empty zombie mind with a forlorn barely readable weatherbeaten 'For Rent' sign still vainly flapping outside on the weed encrusted pole - in celebration of what could have been, but wasn't and is not to be now either." ___ 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] Difference in GPS antennas
On 8/15/09 3:25 PM, "Chuck Harris" wrote: > Lux, Jim (337C) wrote: >> >> >> On 8/15/09 8:27 AM, "Magnus Danielson" wrote: >> >> If you're near a harbor with fishing boats, you'll see plenty of quad helices about a half a meter in overall height, used for VHF Weather satellite reception. They're also used on spacecraft (Mars Science Lander, Mars Reconnaissance Orbiter, and Phoenix all have UHF quad helix antennas, I think, for about 400 MHz) >>> Not used by the fishing vesels near me... >> >> Really? Practically all the fishing boats (mostly squid) boats going out >> from Ventura Harbor (in Southern California) have big ol' quad helix >> antennas up on the cross bar (as well as the usual HF SSB and VHF whips and >> the radar). Maybe it's a regional preference thing (or folks are going to >> the 1.6 GHz band or something). > > Haven't all of the VHF weather satellites been decommissioned? Could be. I suspect that those antennas have been up on those boats for decades. ___ 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] OCXO sensitive to gravity
Oops. It looks like they sense the force from the Bourdon tube, rather than the displacement. -John === > Yes... it was not cheap, exactly :) It was from this company: > http://www.paroscientific.com/ > > Regards, > > Javier > > > > J. Forster escribió: >> Oh, I know there are quartz transducers like accelerometers, pressure >> and >> force gages, etc. from companies like Endevco, Kiag/Krystal, and others. >> But in my experience they are lab instruments costing a bundle. >> >> The airbag sensors are cheap... likely a buck or twp. Hence the use of >> silicon. >> >> Best, >> -John >> >> === >> >> >>> J. Forster escribió: > As you feel your heart beat, google for Quartz Pressure Sensor Again, I think these are semiconductor sensors. >>> Yes, but there are also quartz pressure sensors. Long time ago I used a >>> equipment to measure water columns (and hence sea waves height) that >>> used a quartz-based pressure sensor. It was a very sensitive equipment. >>> >>> Regards, >>> >>> Javier >>> >>> -- >>> >>> Javier HerreroEMAIL: >>> jherr...@hvsistemas.com >>> HV Sistemas S.L. PHONE: +34 949 336 >>> 806 >>> Los Charcones, 17AFAX: +34 949 336 >>> 792 >>> 19170 El Casar - Guadalajara - Spain WEB: >>> http://www.hvsistemas.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. >> >> > > -- > > Javier HerreroEMAIL: jherr...@hvsistemas.com > HV Sistemas S.L. PHONE: +34 949 336 806 > Los Charcones, 17AFAX: +34 949 336 792 > 19170 El Casar - Guadalajara - Spain WEB: http://www.hvsistemas.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.
Re: [time-nuts] Difference in GPS antennas
Lux, Jim (337C) wrote: On 8/15/09 8:27 AM, "Magnus Danielson" wrote: If you're near a harbor with fishing boats, you'll see plenty of quad helices about a half a meter in overall height, used for VHF Weather satellite reception. They're also used on spacecraft (Mars Science Lander, Mars Reconnaissance Orbiter, and Phoenix all have UHF quad helix antennas, I think, for about 400 MHz) Not used by the fishing vesels near me... Really? Practically all the fishing boats (mostly squid) boats going out from Ventura Harbor (in Southern California) have big ol' quad helix antennas up on the cross bar (as well as the usual HF SSB and VHF whips and the radar). Maybe it's a regional preference thing (or folks are going to the 1.6 GHz band or something). Haven't all of the VHF weather satellites been decommissioned? -Chuck Harris ___ 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 5065A Rubidium
Mine is the 10811-60109.serial number prefix is 2432. Bought the unit at The Huntsville Hamfest today. I knew the test equipment dealer and he let me take the unit home to check it and so far it appears to be OK. I had to adjust the coarse frequency before I closed the loop, as it had high error voltage. I let it warm up about 30 minutes, and then adjusted it against a GPSDO, closed the loop, reset the logic and I have continuous operation light and all the meter readings are close to the recorded values. After an hour, I did a quick drift test and I have 8x10E-12 in 2 minutes. Its 20 years old according to the recorded meter readings. Its just a rubidium oscillator. No digital clock or 1 PPS circuits. Looks like I get to go back and pay the man. I love hamfest ! Bruce - I found the manual at Didier's site, but its not for the one I have - but its a good place to start. I looked there before, But I must have been too quick. Thanks. Brian Kirby KD4FM Dan Rae wrote: Brian Kirby wrote: Anybody know where I can find a PDF of the HP 5065A rubidium frequency standard ? Brian, assuming you mean the manual, Artek Media have one for sale, but it is for the older versions. I have never been able to find one for the later versions that use the 10811 OCXO. Dan ___ 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] Difference in GPS antennas
As I recall, this is the type of antenna my handheld GPSr has. I had a set of batteries bleed out in and had to disassemble it in order to do a good cleaning. -Dave - Original Message - From: "Magnus Danielson" To: "Discussion of precise time and frequency measurement" Sent: Saturday, August 15, 2009 9:27:30 AM GMT -07:00 US/Canada Mountain Subject: Re: [time-nuts] Difference in GPS antennas Lux, Jim (337C) wrote: > > > On 8/15/09 7:58 AM, "Magnus Danielson" wrote: > >>> Thats a quadrifilar helix antenna. >> A quite traditional antenna form. >> >> Not sure I have one of those around here. >> >> > > If you're near a harbor with fishing boats, you'll see plenty of quad > helices about a half a meter in overall height, used for VHF Weather > satellite reception. They're also used on spacecraft (Mars Science Lander, > Mars Reconnaissance Orbiter, and Phoenix all have UHF quad helix antennas, I > think, for about 400 MHz) Not used by the fishing vesels near me... I didn't mean helixantennas as such, I was just asking myself the question if any of my *GPS* antennas was infact of the quadra-helix design, a few of them have the sizes that they *could* be that. > The 4 helices need to be fed in the appropriate phase (0,90,180,270), > usually, they're fed in pairs (a differential signal feeds 0,180 and another > feeds 90/270) > > There are several ways to phase them, depending on the bandwidth > requirements. A quadrature hybrid is one way. The other is to make one helix > slightly longer than resonant and the other slightly shorter. A typical GPS sat has two rings of helix antennas, an inner and outer ring. These create a far-distance shape of lobes that i circularly fairly even but pushes more energy towards the edge of the earth, as seen from the satellite, such that the additional space loss from increased distance is being somewhat equalized by the GPS antenna. That's the trick being used to reduce the power variations from the GPS sats as experienced by the user. Cheers, Magnus ___ 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] OCXO sensitive to gravity
Do you mean a quartz manometer? If so, those are many, many kilobucks. They don't use a quartz crystal, however. They are Bourdon Tube technology, at least the TI ones are. There is a helix of fused quartz tubing, like a spiral condensor you'd see in a chemistry lab, inside a jar. There is a mirror mounted on one end and a servo system to keep the mirror at null. When positive pressure is applied, the helix uncurls a bit and the servo turns the whole assembly and nulls out the mirror. The servo motion is proportional to pressure. I've used them to measure 1 atm = 760 mm Hg down to better tha 0.01 mm Hg. They work for absolute or differential pressures. Quartz is used because it makes a VERY good spring. Best, -John = > Yes... it was not cheap, exactly :) It was from this company: > http://www.paroscientific.com/ > > Regards, > > Javier > > > > J. Forster escribió: >> Oh, I know there are quartz transducers like accelerometers, pressure >> and >> force gages, etc. from companies like Endevco, Kiag/Krystal, and others. >> But in my experience they are lab instruments costing a bundle. >> >> The airbag sensors are cheap... likely a buck or twp. Hence the use of >> silicon. >> >> Best, >> -John >> >> === >> >> >>> J. Forster escribió: > As you feel your heart beat, google for Quartz Pressure Sensor Again, I think these are semiconductor sensors. >>> Yes, but there are also quartz pressure sensors. Long time ago I used a >>> equipment to measure water columns (and hence sea waves height) that >>> used a quartz-based pressure sensor. It was a very sensitive equipment. >>> >>> Regards, >>> >>> Javier >>> >>> -- >>> >>> Javier HerreroEMAIL: >>> jherr...@hvsistemas.com >>> HV Sistemas S.L. PHONE: +34 949 336 >>> 806 >>> Los Charcones, 17AFAX: +34 949 336 >>> 792 >>> 19170 El Casar - Guadalajara - Spain WEB: >>> http://www.hvsistemas.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. >> >> > > -- > > Javier HerreroEMAIL: jherr...@hvsistemas.com > HV Sistemas S.L. PHONE: +34 949 336 806 > Los Charcones, 17AFAX: +34 949 336 792 > 19170 El Casar - Guadalajara - Spain WEB: http://www.hvsistemas.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.
Re: [time-nuts] OCXO sensitive to gravity
We used an Rb magnetometer to measure total charge change due to lightning in 1964 or thereabout- Don Latham Tom Van Baak > Although we time-nuts prize quartz oscillators that are highly-stable > and well-insulated from environmental effects there is an entire > industry doing the exact opposite -- using quartz as a sensor. > > Some of the best thermometers are based on quartz oscillators > (hp 2804A) cut to maximize, rather than minimize, their tempco. > > And billions of accelerometers (from air bag sensors to Wii game > controllers to the iPod touch and iPhone) have been produced in > the past decade. Google words like MEMS Quartz Accelerometer. > Also for Quartz Rate Sensor QRS. > > I've seen quartz resonators used to measure to impurities in the > making of semiconductor wafers -- they measure the change in > frequency of an exposed quartz resonator as atoms fall on the > exposed crystal and change its frequency. Note that a 1 mm > quartz crystal is only about a million molecules thick. So adding > a layer of only 1 atom will change the frequency in the ppm range. > We can measure a thousand or million times better than that. > > As you feel your heart beat, google for Quartz Pressure Sensor > > Quartz is really quite amazing. It's almost a shame to shield it > from everything so all they have left to do is try to measure time! > > One other note: rubidium vapor frequency standards are much > more sensitive to magnetic fields than cesium beam standards. > I've heard that military sub-hunting sea planes use deliberately > un-shielded rubidium clocks to detect hidden submarines. Google > for words like Rubidium Magnetometer ASW P-3 Zeeman > > As always, one man's error is another man's signal... > > /tvb > http://www.LeapSecond.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. > -- Dr. Don Latham AJ7LL Six Mile Systems LLP 17850 Six Mile Road POB 134 Huson, MT, 59846 VOX 406-626-4304 www.lightningforensics.com www.sixmilesystems.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] OCXO sensitive to gravity
Yes... it was not cheap, exactly :) It was from this company: http://www.paroscientific.com/ Regards, Javier J. Forster escribió: Oh, I know there are quartz transducers like accelerometers, pressure and force gages, etc. from companies like Endevco, Kiag/Krystal, and others. But in my experience they are lab instruments costing a bundle. The airbag sensors are cheap... likely a buck or twp. Hence the use of silicon. Best, -John === J. Forster escribió: As you feel your heart beat, google for Quartz Pressure Sensor Again, I think these are semiconductor sensors. Yes, but there are also quartz pressure sensors. Long time ago I used a equipment to measure water columns (and hence sea waves height) that used a quartz-based pressure sensor. It was a very sensitive equipment. Regards, Javier -- Javier HerreroEMAIL: jherr...@hvsistemas.com HV Sistemas S.L. PHONE: +34 949 336 806 Los Charcones, 17AFAX: +34 949 336 792 19170 El Casar - Guadalajara - Spain WEB: http://www.hvsistemas.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. -- Javier HerreroEMAIL: jherr...@hvsistemas.com HV Sistemas S.L. PHONE: +34 949 336 806 Los Charcones, 17AFAX: +34 949 336 792 19170 El Casar - Guadalajara - Spain WEB: http://www.hvsistemas.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] HP 5065A Rubidium
Brian Kirby wrote: > > Anybody know where I can find a PDF of the HP 5065A rubidium frequency > standard ? > > Brian Kirby KD4FM >> There's one in the manuals section of Didier's site. Bruce ___ 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 5065A Rubidium
Brian Kirby wrote: Anybody know where I can find a PDF of the HP 5065A rubidium frequency standard ? Brian, assuming you mean the manual, Artek Media have one for sale, but it is for the older versions. I have never been able to find one for the later versions that use the 10811 OCXO. Dan ___ 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] OCXO sensitive to gravity
Oh, I know there are quartz transducers like accelerometers, pressure and force gages, etc. from companies like Endevco, Kiag/Krystal, and others. But in my experience they are lab instruments costing a bundle. The airbag sensors are cheap... likely a buck or twp. Hence the use of silicon. Best, -John === > J. Forster escribió: >> >> >>> As you feel your heart beat, google for Quartz Pressure Sensor >> >> Again, I think these are semiconductor sensors. >> > Yes, but there are also quartz pressure sensors. Long time ago I used a > equipment to measure water columns (and hence sea waves height) that > used a quartz-based pressure sensor. It was a very sensitive equipment. > > Regards, > > Javier > > -- > > Javier HerreroEMAIL: jherr...@hvsistemas.com > HV Sistemas S.L. PHONE: +34 949 336 806 > Los Charcones, 17AFAX: +34 949 336 792 > 19170 El Casar - Guadalajara - Spain WEB: http://www.hvsistemas.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.
Re: [time-nuts] OCXO sensitive to gravity
J. Forster escribió: As you feel your heart beat, google for Quartz Pressure Sensor Again, I think these are semiconductor sensors. Yes, but there are also quartz pressure sensors. Long time ago I used a equipment to measure water columns (and hence sea waves height) that used a quartz-based pressure sensor. It was a very sensitive equipment. Regards, Javier -- Javier HerreroEMAIL: jherr...@hvsistemas.com HV Sistemas S.L. PHONE: +34 949 336 806 Los Charcones, 17AFAX: +34 949 336 792 19170 El Casar - Guadalajara - Spain WEB: http://www.hvsistemas.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] OCXO sensitive to gravity
I don't know. I'm just the lab tech! I cater to national labs, in particular LANL which is right down the street from me. I've been involved with the guy that developed SFAI (swept frequency acoustic interferometry). We use this technique to fingerprint and characterize various substances -anything from oil/water cut in the petrolieum industry to nerve agents in Iraqi shells (original design purpose), to determining what liquid is in the bottle packed in your carry on luggage. I'm familliar with all of the measurment processes and have acted as the hands of the scientists on more than one occasion but simply don't know enough to know if this level of precision matters or not. -Bob On Sat, Aug 15, 2009 at 2:29 PM, WB6BNQ wrote: > Hi Bob, > > Why do they have to be so precise ? And what are they being used for ? > > BillWB6BNQ > > Robert Darlington wrote: > > > One of my side jobs is to produce better than state of the art ultrasound > > transducers. That being said, there is nothing particularly better about > > mine other than when I say it's a 1MHz transducer, I really mean > 1.0Mhz, > > not 980kHz, not 1.2Mhz. The way I achieve this is to lay down gold, a > few > > atoms at a time, and track a resonance peak (network analyzer and some > > simple code in VB of all things). We actually drive the transducer as we > > sputter coat the gold on top and can see the resonance point shift, real > > time. Cool stuff. They use a similar process in industry but they're > > looking at one data point in a vacuum chamber full of transducers. I'm > > looking at every single one. > > > > -Bob > > > > On Sat, Aug 15, 2009 at 1:56 PM, J. Forster wrote: > > > > > > And billions of accelerometers (from air bag sensors to Wii game > > > > controllers to the iPod touch and iPhone) have been produced in > > > > the past decade. Google words like MEMS Quartz Accelerometer. > > > > Also for Quartz Rate Sensor QRS. > > > > > > I'm not so sure they use quartz. The ones I've seen are micromachined > from > > > silicon and have both the beam and electronics on the same chip. > > > > > > > I've seen quartz resonators used to measure to impurities in the > > > > making of semiconductor wafers -- they measure the change in > > > > frequency of an exposed quartz resonator as atoms fall on the > > > > exposed crystal and change its frequency. Note that a 1 mm > > > > quartz crystal is only about a million molecules thick. So adding > > > > a layer of only 1 atom will change the frequency in the ppm range. > > > > We can measure a thousand or million times better than that. > > > > > > Not impurities, but the deposition of metalizing films, etc. > > > > > > > As you feel your heart beat, google for Quartz Pressure Sensor > > > > > > Again, I think these are semiconductor sensors. > > > > > > > Quartz is really quite amazing. It's almost a shame to shield it > > > > from everything so all they have left to do is try to measure time! > > > > > > LoL. The crystals ARE pretty nice. > > > > > > Best, > > > -John > > > > > > > > One other note: rubidium vapor frequency standards are much > > > > more sensitive to magnetic fields than cesium beam standards. > > > > I've heard that military sub-hunting sea planes use deliberately > > > > un-shielded rubidium clocks to detect hidden submarines. Google > > > > for words like Rubidium Magnetometer ASW P-3 Zeeman > > > > > > > > As always, one man's error is another man's signal... > > > > > > > > /tvb > > > > http://www.LeapSecond.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 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] OCXO sensitive to gravity
On 8/15/09 2:32 PM, "Rick Karlquist" wrote: > Robert Darlington wrote: >> not 980kHz, not 1.2Mhz. The way I achieve this is to lay down gold, a few >> atoms at a time, and track a resonance peak (network analyzer and some >> simple code in VB of all things). We actually drive the transducer as we >> sputter coat the gold on top and can see the resonance point shift, real >> time. Cool stuff. They use a similar process in industry but they're >> looking at one data point in a vacuum chamber full of transducers. I'm >> looking at every single one. >> >> -Bob > > The 10811 crystals were made this way. One at a time, they were > coated with gold while connected to a network analyzer. > > Ditto for the crystals used in Ultra Stable Oscillators. The real art, though, is in picking the right frequency to go to, so that after you've going through the initial aging, it's right on where you want. Very much a build 20 to get 1 good one sort of process. ___ 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] OCXO sensitive to gravity
On 8/15/09 11:32 AM, "saidj...@aol.com" wrote: > Hi Warren, > > that's a smart idea. > > It's fun to try different OCXO types out for their individual > sensitivities. I have seen some that are only sensitive in one single axis, > others that > react on several axie. > > To take your concept further, one could also orient the OCXO to minimize > the effect of vibration as well (caused by e.g. power supply transformers, > fans, walking in the room etc). > > If I read the post correctly, someone said they can literally "talk" to > their DRO, and make the voice come out of their Spectrum Analyzers FM > demodulation loudspeaker. After all, crystals are quite microphonic as well. Yes.. In our case, though, I think the microphonics were from movement of the cavity lid, which wasn't very rigid. The lid moved, moving the tuning screw, which moved the little tuning plate suspended over the ceramic puck. It was a prototype to be sure, so the production item wouldn't be as bad, but that sort of thing convinced me that anything we could do to reduce the amount of touch labor needed was to the better. ___ 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] OCXO sensitive to gravity
Robert Darlington wrote: > not 980kHz, not 1.2Mhz. The way I achieve this is to lay down gold, a few > atoms at a time, and track a resonance peak (network analyzer and some > simple code in VB of all things). We actually drive the transducer as we > sputter coat the gold on top and can see the resonance point shift, real > time. Cool stuff. They use a similar process in industry but they're > looking at one data point in a vacuum chamber full of transducers. I'm > looking at every single one. > > -Bob The 10811 crystals were made this way. One at a time, they were coated with gold while connected to a network analyzer. Rick Karlquist N6RK ___ 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] Difference in GPS antennas
On 8/15/09 8:27 AM, "Magnus Danielson" wrote: >> If you're near a harbor with fishing boats, you'll see plenty of quad >> helices about a half a meter in overall height, used for VHF Weather >> satellite reception. They're also used on spacecraft (Mars Science Lander, >> Mars Reconnaissance Orbiter, and Phoenix all have UHF quad helix antennas, I >> think, for about 400 MHz) > > Not used by the fishing vesels near me... Really? Practically all the fishing boats (mostly squid) boats going out from Ventura Harbor (in Southern California) have big ol' quad helix antennas up on the cross bar (as well as the usual HF SSB and VHF whips and the radar). Maybe it's a regional preference thing (or folks are going to the 1.6 GHz band or something). > > I didn't mean helixantennas as such, I was just asking myself the > question if any of my *GPS* antennas was infact of the quadra-helix > design, a few of them have the sizes that they *could* be that. The one on my handheld Garmin (about 10 years old) is a quad helix. I would venture that any of the antennas that are about the size of your finger are a quad helix. Thinking of other antennas in that form factor (10-15 cm long, more than 1 cm in diameter) maybe Iridium or Globalstar phones use a quad helix? ___ 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] OCXO sensitive to gravity
Another nifty application of the effect is the resonant beam balance. Basically it can weigh things at the molecular level by measuring the change in frequency of a vibrating quartz or silicon beam... it can be tricky getting and keeping your sample on the "scale"... _ Windows Live™: Keep your life in sync. http://windowslive.com/explore?ocid=PID23384::T:WLMTAGL:ON:WL:en-US:NF_BR_sync:082009 ___ 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 5065A Rubidium
Anybody know where I can find a PDF of the HP 5065A rubidium frequency standard ? Brian Kirby KD4FM ___ 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] OCXO sensitive to gravity
I was basically doing the same thing with another type of sensor, but plated on the gold and then etched it away until joy was maximized... The way I achieve this is to lay down gold, a few atoms at a time, and track a resonance peak (network analyzer and some simple code in VB of all things). _ Get your vacation photos on your phone! http://windowsliveformobile.com/en-us/photos/default.aspx?&OCID=0809TL-HM ___ 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] OCXO sensitive to gravity
Real time monitoring of the objective is a good way to go. I don't thing making semiconductor or mirors is as critical, hence a chamber monitor suffices. -John == > One of my side jobs is to produce better than state of the art ultrasound > transducers. That being said, there is nothing particularly better about > mine other than when I say it's a 1MHz transducer, I really mean > 1.0Mhz, > not 980kHz, not 1.2Mhz. The way I achieve this is to lay down gold, a few > atoms at a time, and track a resonance peak (network analyzer and some > simple code in VB of all things). We actually drive the transducer as we > sputter coat the gold on top and can see the resonance point shift, real > time. Cool stuff. They use a similar process in industry but they're > looking at one data point in a vacuum chamber full of transducers. I'm > looking at every single one. > > -Bob > > On Sat, Aug 15, 2009 at 1:56 PM, J. Forster wrote: > >> > And billions of accelerometers (from air bag sensors to Wii game >> > controllers to the iPod touch and iPhone) have been produced in >> > the past decade. Google words like MEMS Quartz Accelerometer. >> > Also for Quartz Rate Sensor QRS. >> >> I'm not so sure they use quartz. The ones I've seen are micromachined >> from >> silicon and have both the beam and electronics on the same chip. >> >> > I've seen quartz resonators used to measure to impurities in the >> > making of semiconductor wafers -- they measure the change in >> > frequency of an exposed quartz resonator as atoms fall on the >> > exposed crystal and change its frequency. Note that a 1 mm >> > quartz crystal is only about a million molecules thick. So adding >> > a layer of only 1 atom will change the frequency in the ppm range. >> > We can measure a thousand or million times better than that. >> >> Not impurities, but the deposition of metalizing films, etc. >> >> > As you feel your heart beat, google for Quartz Pressure Sensor >> >> Again, I think these are semiconductor sensors. >> >> > Quartz is really quite amazing. It's almost a shame to shield it >> > from everything so all they have left to do is try to measure time! >> >> LoL. The crystals ARE pretty nice. >> >> Best, >> -John >> > >> > One other note: rubidium vapor frequency standards are much >> > more sensitive to magnetic fields than cesium beam standards. >> > I've heard that military sub-hunting sea planes use deliberately >> > un-shielded rubidium clocks to detect hidden submarines. Google >> > for words like Rubidium Magnetometer ASW P-3 Zeeman >> > >> > As always, one man's error is another man's signal... >> > >> > /tvb >> > http://www.LeapSecond.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.
Re: [time-nuts] OCXO sensitive to gravity
Hi Bob, Why do they have to be so precise ? And what are they being used for ? BillWB6BNQ Robert Darlington wrote: > One of my side jobs is to produce better than state of the art ultrasound > transducers. That being said, there is nothing particularly better about > mine other than when I say it's a 1MHz transducer, I really mean 1.0Mhz, > not 980kHz, not 1.2Mhz. The way I achieve this is to lay down gold, a few > atoms at a time, and track a resonance peak (network analyzer and some > simple code in VB of all things). We actually drive the transducer as we > sputter coat the gold on top and can see the resonance point shift, real > time. Cool stuff. They use a similar process in industry but they're > looking at one data point in a vacuum chamber full of transducers. I'm > looking at every single one. > > -Bob > > On Sat, Aug 15, 2009 at 1:56 PM, J. Forster wrote: > > > > And billions of accelerometers (from air bag sensors to Wii game > > > controllers to the iPod touch and iPhone) have been produced in > > > the past decade. Google words like MEMS Quartz Accelerometer. > > > Also for Quartz Rate Sensor QRS. > > > > I'm not so sure they use quartz. The ones I've seen are micromachined from > > silicon and have both the beam and electronics on the same chip. > > > > > I've seen quartz resonators used to measure to impurities in the > > > making of semiconductor wafers -- they measure the change in > > > frequency of an exposed quartz resonator as atoms fall on the > > > exposed crystal and change its frequency. Note that a 1 mm > > > quartz crystal is only about a million molecules thick. So adding > > > a layer of only 1 atom will change the frequency in the ppm range. > > > We can measure a thousand or million times better than that. > > > > Not impurities, but the deposition of metalizing films, etc. > > > > > As you feel your heart beat, google for Quartz Pressure Sensor > > > > Again, I think these are semiconductor sensors. > > > > > Quartz is really quite amazing. It's almost a shame to shield it > > > from everything so all they have left to do is try to measure time! > > > > LoL. The crystals ARE pretty nice. > > > > Best, > > -John > > > > > > One other note: rubidium vapor frequency standards are much > > > more sensitive to magnetic fields than cesium beam standards. > > > I've heard that military sub-hunting sea planes use deliberately > > > un-shielded rubidium clocks to detect hidden submarines. Google > > > for words like Rubidium Magnetometer ASW P-3 Zeeman > > > > > > As always, one man's error is another man's signal... > > > > > > /tvb > > > http://www.LeapSecond.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 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] OCXO sensitive to gravity
One of my side jobs is to produce better than state of the art ultrasound transducers. That being said, there is nothing particularly better about mine other than when I say it's a 1MHz transducer, I really mean 1.0Mhz, not 980kHz, not 1.2Mhz. The way I achieve this is to lay down gold, a few atoms at a time, and track a resonance peak (network analyzer and some simple code in VB of all things). We actually drive the transducer as we sputter coat the gold on top and can see the resonance point shift, real time. Cool stuff. They use a similar process in industry but they're looking at one data point in a vacuum chamber full of transducers. I'm looking at every single one. -Bob On Sat, Aug 15, 2009 at 1:56 PM, J. Forster wrote: > > And billions of accelerometers (from air bag sensors to Wii game > > controllers to the iPod touch and iPhone) have been produced in > > the past decade. Google words like MEMS Quartz Accelerometer. > > Also for Quartz Rate Sensor QRS. > > I'm not so sure they use quartz. The ones I've seen are micromachined from > silicon and have both the beam and electronics on the same chip. > > > I've seen quartz resonators used to measure to impurities in the > > making of semiconductor wafers -- they measure the change in > > frequency of an exposed quartz resonator as atoms fall on the > > exposed crystal and change its frequency. Note that a 1 mm > > quartz crystal is only about a million molecules thick. So adding > > a layer of only 1 atom will change the frequency in the ppm range. > > We can measure a thousand or million times better than that. > > Not impurities, but the deposition of metalizing films, etc. > > > As you feel your heart beat, google for Quartz Pressure Sensor > > Again, I think these are semiconductor sensors. > > > Quartz is really quite amazing. It's almost a shame to shield it > > from everything so all they have left to do is try to measure time! > > LoL. The crystals ARE pretty nice. > > Best, > -John > > > > One other note: rubidium vapor frequency standards are much > > more sensitive to magnetic fields than cesium beam standards. > > I've heard that military sub-hunting sea planes use deliberately > > un-shielded rubidium clocks to detect hidden submarines. Google > > for words like Rubidium Magnetometer ASW P-3 Zeeman > > > > As always, one man's error is another man's signal... > > > > /tvb > > http://www.LeapSecond.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.
Re: [time-nuts] OCXO sensitive to gravity
saidj...@aol.com wrote: > If I read the post correctly, someone said they can literally "talk" to > their DRO, and make the voice come out of their Spectrum Analyzers FM > demodulation loudspeaker. After all, crystals are quite microphonic as > well. > > bye, > Said A well used trick with the HP608 signal generator, which did not have frequency modulation, was to mount a speaker on the side of the case and drive it with 1 kHz to generate FM using microphonics. It supposedly worked quite well and could even be calibrated. Rick Karlquist N6RK ___ 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] OCXO sensitive to gravity
> And billions of accelerometers (from air bag sensors to Wii game > controllers to the iPod touch and iPhone) have been produced in > the past decade. Google words like MEMS Quartz Accelerometer. > Also for Quartz Rate Sensor QRS. I'm not so sure they use quartz. The ones I've seen are micromachined from silicon and have both the beam and electronics on the same chip. > I've seen quartz resonators used to measure to impurities in the > making of semiconductor wafers -- they measure the change in > frequency of an exposed quartz resonator as atoms fall on the > exposed crystal and change its frequency. Note that a 1 mm > quartz crystal is only about a million molecules thick. So adding > a layer of only 1 atom will change the frequency in the ppm range. > We can measure a thousand or million times better than that. Not impurities, but the deposition of metalizing films, etc. > As you feel your heart beat, google for Quartz Pressure Sensor Again, I think these are semiconductor sensors. > Quartz is really quite amazing. It's almost a shame to shield it > from everything so all they have left to do is try to measure time! LoL. The crystals ARE pretty nice. Best, -John > > One other note: rubidium vapor frequency standards are much > more sensitive to magnetic fields than cesium beam standards. > I've heard that military sub-hunting sea planes use deliberately > un-shielded rubidium clocks to detect hidden submarines. Google > for words like Rubidium Magnetometer ASW P-3 Zeeman > > As always, one man's error is another man's signal... > > /tvb > http://www.LeapSecond.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] OCXO sensitive to gravity
Although we time-nuts prize quartz oscillators that are highly-stable and well-insulated from environmental effects there is an entire industry doing the exact opposite -- using quartz as a sensor. Some of the best thermometers are based on quartz oscillators (hp 2804A) cut to maximize, rather than minimize, their tempco. And billions of accelerometers (from air bag sensors to Wii game controllers to the iPod touch and iPhone) have been produced in the past decade. Google words like MEMS Quartz Accelerometer. Also for Quartz Rate Sensor QRS. I've seen quartz resonators used to measure to impurities in the making of semiconductor wafers -- they measure the change in frequency of an exposed quartz resonator as atoms fall on the exposed crystal and change its frequency. Note that a 1 mm quartz crystal is only about a million molecules thick. So adding a layer of only 1 atom will change the frequency in the ppm range. We can measure a thousand or million times better than that. As you feel your heart beat, google for Quartz Pressure Sensor Quartz is really quite amazing. It's almost a shame to shield it from everything so all they have left to do is try to measure time! One other note: rubidium vapor frequency standards are much more sensitive to magnetic fields than cesium beam standards. I've heard that military sub-hunting sea planes use deliberately un-shielded rubidium clocks to detect hidden submarines. Google for words like Rubidium Magnetometer ASW P-3 Zeeman As always, one man's error is another man's signal... /tvb http://www.LeapSecond.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] OCXO sensitive to gravity
Hi Warren, that's a smart idea. It's fun to try different OCXO types out for their individual sensitivities. I have seen some that are only sensitive in one single axis, others that react on several axie. To take your concept further, one could also orient the OCXO to minimize the effect of vibration as well (caused by e.g. power supply transformers, fans, walking in the room etc). If I read the post correctly, someone said they can literally "talk" to their DRO, and make the voice come out of their Spectrum Analyzers FM demodulation loudspeaker. After all, crystals are quite microphonic as well. bye, Said In a message dated 8/15/2009 09:46:46 Pacific Daylight Time, warrensjmail-...@yahoo.com writes: When possible, the thing I do to eliminate the effect of small gravitational changes or tilt from effecting the Freq of my Oscillators, is to orientate their case so that the osc is approximately at its MAXIMUM 2G turn over axes. This gives the osc a null to small gravitational changes, much the same as setting the temp of an oven to the zero TC freq turn over point. To optimize further, the axes can be fine adjusted so that a small tilt in any direction causes the same direction in freq shift. The improvement achieved can be quick substantial like 100 to 1 improvement. ws ___ 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] OCXO sensitive to gravity
When possible, the thing I do to eliminate the effect of small gravitational changes or tilt from effecting the Freq of my Oscillators, is to orientate their case so that the osc is approximately at its MAXIMUM 2G turn over axes. This gives the osc a null to small gravitational changes, much the same as setting the temp of an oven to the zero TC freq turn over point. To optimize further, the axes can be fine adjusted so that a small tilt in any direction causes the same direction in freq shift. The improvement achieved can be quick substantial like 100 to 1 improvement. ws *** - Original Message - From: To: Sent: Thursday, August 13, 2009 5:14 PM Subject: Re: [time-nuts] OCXO sensitive to gravity > Hi there, > > there are special low-g OCXO's out there. We offer one that has better than > 3E-010 per g per axis, which is about 10x better than your "standard" > OCXO. > > This is also important for stationary applications where the unit is not > tilted, for vibration-induced phase-noise is also that much smaller with a > low-g OCXO versus a standard OCXO. > > bye, > Said > > > In a message dated 8/13/2009 11:02:51 Pacific Daylight Time, > wpxs...@gmail.com writes: > > A while back there was some discussion about crystal oscillator's changing > frequency due to the effects of gravity. Since I got my Z3801 up and > running > full time, I have been trying to characterize some OCXOs I had picked off > eBay but had no specifications for. I was trying to fine tune one to the > '3801 and noticed that when I picked it up and tilted it to get to the > adjustment , the frequency changed. I started rotating it 90 degrees at at > time and noticed that the frequency changed up or down depending on which > it > was oriented. The change was immediate and quite noticeable. It is nice to > have something as stable as the Z3801 but now I realize all those OCXOs I > thought were so great, aren't. I do see why the rubidium sources are well > liked. They lock in a couple of minutes and that's pretty much it. The ones > I bought off eBay were both off by about 1E-9. It occurred to me that they > probably in equipment where they were locked to GPS and with nothing > connected to the frequency control input, they would naturally be a little > off. > ___ > > > ___ 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] Difference in GPS antennas
Lux, Jim (337C) wrote: On 8/15/09 7:58 AM, "Magnus Danielson" wrote: Thats a quadrifilar helix antenna. A quite traditional antenna form. Not sure I have one of those around here. If you're near a harbor with fishing boats, you'll see plenty of quad helices about a half a meter in overall height, used for VHF Weather satellite reception. They're also used on spacecraft (Mars Science Lander, Mars Reconnaissance Orbiter, and Phoenix all have UHF quad helix antennas, I think, for about 400 MHz) Not used by the fishing vesels near me... I didn't mean helixantennas as such, I was just asking myself the question if any of my *GPS* antennas was infact of the quadra-helix design, a few of them have the sizes that they *could* be that. The 4 helices need to be fed in the appropriate phase (0,90,180,270), usually, they're fed in pairs (a differential signal feeds 0,180 and another feeds 90/270) There are several ways to phase them, depending on the bandwidth requirements. A quadrature hybrid is one way. The other is to make one helix slightly longer than resonant and the other slightly shorter. A typical GPS sat has two rings of helix antennas, an inner and outer ring. These create a far-distance shape of lobes that i circularly fairly even but pushes more energy towards the edge of the earth, as seen from the satellite, such that the additional space loss from increased distance is being somewhat equalized by the GPS antenna. That's the trick being used to reduce the power variations from the GPS sats as experienced by the user. Cheers, Magnus ___ 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] Difference in GPS antennas
On 8/15/09 7:58 AM, "Magnus Danielson" wrote: >>> >>> >>> >> Thats a quadrifilar helix antenna. > > A quite traditional antenna form. > > Not sure I have one of those around here. > > If you're near a harbor with fishing boats, you'll see plenty of quad helices about a half a meter in overall height, used for VHF Weather satellite reception. They're also used on spacecraft (Mars Science Lander, Mars Reconnaissance Orbiter, and Phoenix all have UHF quad helix antennas, I think, for about 400 MHz) The 4 helices need to be fed in the appropriate phase (0,90,180,270), usually, they're fed in pairs (a differential signal feeds 0,180 and another feeds 90/270) There are several ways to phase them, depending on the bandwidth requirements. A quadrature hybrid is one way. The other is to make one helix slightly longer than resonant and the other slightly shorter. ___ 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] Difference in GPS antennas
Bruce Griffiths wrote: Hal Murray wrote: My Panasonic VIC100 antenna had a few screws to hold the bottom to the plastic cone top. The bottom had an o-ring seal that stuck a little but was still pretty easy to slide the bottom from the top half. Inside was a patch antenna on top of a pcb. Thanks. I tried again and it came apart easily. There is an O-ring but no glue. (I wonder why I didn't get it the first try.) The antenna isn't a patch. (Or I don't recognize it as such.) It's a cylinder, 2 inches tall, 3/4 inch in dia, sticking up over a 2 inch square PCB that's screwed into an aluminum base place. It's made of flexible PCB material wrapped around to make a cylinder. The outside bottom 3/4 inch is a plane. There is an obvious solder joint line closing the plane. The inside top has 4 fingers spiraling around at 45 degrees. The lower inside part (opposite the plane) has some wiggles in some traces, but I haven't figured out the equivalent circuit. Thats a quadrifilar helix antenna. A quite traditional antenna form. Not sure I have one of those around here. Cheers, Magnus ___ 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] Difference in GPS antennas
Joseph M Gwinn wrote: Bob, time-nuts-boun...@febo.com wrote on 08/14/2009 01:05:34 PM: From: Robert Darlington To: Discussion of precise time and frequency measurement Date: 08/14/2009 02:06 PM Subject: Re: [time-nuts] Difference in GPS antennas Sent by: time-nuts-boun...@febo.com Hrm, I'm looking for a sheet of Eccosorb to make an anechoic chamber (a very small one) for testing 2.4GHz printed (PCB) antennas. I'd be interested in knowing the specs. The idea with what I'm doing is that I cansweep the antenna with the network analyzer and still be near the antenna to keep the cables short, while at the same time not interfere with the measurements. I met a guy from Microchip last week that showed me what he was doing and what works well for him. He built a box about 8" high and about 5 inch square on the bottom (inside dimensions). Even though it's pretty parallel on the inside, reflection is a minimum because of the material. The main advice I would give is to make sure the box isn't perfectly square or rectangular, so standing waves cannot form. So, build it sloppy, with walls visibly askew (not perpendicular to one another). That's how my studio is built. Part of it was already there, and the walls I put up just happend to become skewed. Even floor-cieling distance differs significantly. The bare room had no signficant resonance and now stuffed with damping material it has no longer intense reflection either, so it is really pleasent. Need to do a propper sweep thought. So I agree totally with this recommendation! Also recall that near-field responses of an antenna can fool you if you want to know something about the far-field response. So you do want to be at a sufficient distance from the antenna for the worst of the near field response to have started even out to the far-field response. I have done alot of speaker measurements, so I am well aware of the problems involved in near/far field context. Antenna stuff is similar but different. Cheers, Magnus ___ 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] Gravity and OCXOs
When applied to meter movements this is called geotropism. Robert G8RPI --- On Fri, 14/8/09, Magnus Danielson wrote: > From: Magnus Danielson > Subject: Re: [time-nuts] Gravity and OCXOs > To: "Discussion of precise time and frequency measurement" > > Date: Friday, 14 August, 2009, 9:02 AM > Murray Greenman wrote: > > Rick is right. > > > > The effect you see when turning your GPSDO upside down > will be > > predominantly the direct gravitational effect on the > OCXO crystal and > > its mountings. You see this with any OCXO, and the > good ones will have a > > '2G turnover' or other G rating quoted. > > > > For example, the well known HP 10811A specification > says 'Gravitational > > Field: <4 x 10^-9 for 2g static shift (turnover). > That's fairly typical. > > > > I just measured the effect on a good C-MAC 10MHz OCXO > (similar to those > > used in many recent GPSDOs) and measured 40mHz p-p, or > exactly 4e-9. > > > > It's complicated in the GPSDO because the correction > mechanism (via GPS > > 1pps) is much slower than the rate at which you can > change the > > gravitational effect. Rb references simply have a > faster loop and will > > correct the G effect more quickly. > > If you care about that speed, you use GPSes which has > higher speeds and you don't use a PPS since as you pointed > out is unfit for it. Also, if you care about it, you'd use > sensors to sense the gravity and use that for the bulk > adjustment, if a low sensitivity crystal isn't enought or > available in matching specs. > > The PPS is just an arbitrary limit. > > Cheers, > Magnus > > ___ > 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] Coil sensitivity to external magnetic fields...
2009/8/15 steve heidmann : > > Hi Burt , > > Two thousand years ago the Wobulator was invented . An early sweep generator ! Was that one of the first miracles? 73, Steve > > Steve > > --- On Fri, 8/14/09, Burt I. Weiner wrote: > > From: Burt I. Weiner > Subject: [time-nuts] Coil sensitivity to external magnetic fields... > To: time-nuts@febo.com > Date: Friday, August 14, 2009, 6:52 AM > > Pardon me for inter-loping here - I don't know if this has any bearing on the > subject but the following was certainly a learning experience for me. About > a thousand years ago I had an ICOM IC-21A two-meter radio. The speaker coil > opened and the only convenient replacement I could find had a larger magnet. > The speaker for this radio is mounted in the lid. I replaced the speaker and > checked it out before re-assembling the radio. Everything was fine. Once I > re-assembled the radio it was deaf. Figuring I had bumped something I opened > it up to check. With the lid off it worked fine. After a few rounds of this > same exercise I decided I was going to put the lid on with the receiver > operating. What I discovered was that the magnet on the speaker came within > about 1/8" of one of the I.F. cans. The field from the magnet detuned the > I.F. coil. I finally had to order a replacement speaker from ICOM, which > solved the de-tuning problem because > of the smaller magnetic. > > What I learned is that, depending on the resolution of your test equipment, > yes, very small fields, A.C. or D.C. can impose a tuning effect on an > inductor with a Ferris type core. A D.C. field can (shift) de-tune a circuit > and an A.C. field will modulate it by changing the reactance of a Ferris type > core inductor. > > Burt, K6OQK > > > >> Subject: Re: [time-nuts] OCXO sensitive to gravity >> To: Discussion of precise time and frequency measurement >> -1; format=flowed >> >> Bruce Griffiths wrote: >> > Some caution is in order as some ferrites used in RF transformer coils >> > may be permanently altered by application of a strong magnetic filed. >> > Testing at lower fields first would be safer. >> > Setupo a pair of Helmholtz coils and excite them with low frequency AC >> > and look for associated sidebands in the oscillator output. >> > NB a spectrum analyser is unlikely to be sensitive enough for this. >> >> I was just about to say the same. Also, it has much higher repeatability >> and makes quality measures on measures and counter-measures much easier >> to achieve. >> >> Cheers, >> Magnus > > Burt I. Weiner Associates > Broadcast Technical Services > Glendale, California U.S.A. > b...@att.net > K6OQK > > > ___ > 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. > -- Steve Rooke - ZL3TUV & G8KVD A man with one clock knows what time it is; A man with two clocks is never quite sure. ___ 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] Difference in GPS antennas
> Can you take some photographs ? It would be intersting to see it. It > sounds like some dipoles with phasing lines under them possibly. Bruce's call of quadrifilar helix antenna matches what I found via google. I didn't get a good shot looking down inside the cylinder. Here is the outside view: http://www.megapathdsl.net/~hmurray/time-nuts/Lucent-Antenna.jpg -- These are my opinions, not necessarily my employer's. 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.
