Re: [time-nuts] 5950 Crystal impedance meter manual
Hi Luciano: I have some web pages about crystals and testing them: http://www.prc68.com/I/CrystalImpedanceMeters.html - Crystal Impedance Meters (Saunders 150) http://www.prc68.com/I/Xtal.shtml#TE - Crystals in general & Test Equipment (see Trivia below) http://www.prc68.com/I/Xam.html - Crystal Activity Meters http://www.prc68.com/I/Xec.shtml - Equivalent Circuit http://www.prc68.com/I/4395A.shtml#ZT - The Z transform method is also used in commercial crystal test sets like the HP E4915, E4916, E5100. Trivia: The HP 4194 may be the only instrument that can really characterize watch crystals ( 32768 Hz) for impedance which is in the meg Ohms range. Some of the HP network analyzers can fit swept frequency data into an equivalent crystal equivalent circuit. -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html Original Message Hi all, I found this Crystal Impedande Meter produced by RFL Industries inc, Boonton. I would like to understand how to use it and I do not have any documentation. I'm not even able to figure out if it works properly. I would like to ask you if someone owns the service/operating manual and can share it with me. Look at the picture thanks Luciano ___ 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] Possibly interesting book
Hi: Thanks. I read the free part on Amazon and have ordered one of the books from the bibliography: Idea Makers: Personal Perspectives on the Lives & Ideas of Some Notable People <https://www.amazon.com/gp/product/1579550037/ref=od_aui_detailpages00?ie=UTF8=1> Stephen Wolfram It's interesting the the tolerance for the early Watts steam engines was 0.1" in the late 1700s. When I was working with microwave mechanical parts 200 years later (1970s) the no extra charge tolerance was 0.005". The parts I now (40 years later) buy from the local fully automated machine shop have a no extra charge tolerance of 0.0005". They call it 500 millionths since the coordinate measuring machine uses those units. -- Have Fun, Brooke Clarke, N6GCE http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html Original Message WSJ had review of The Perfectionists by Simon Winchester May 5-6( Books). Sounds right up this group's alley. As the reviewer states, it: corrals a large cast of eccentric individuals." Many of which it might have been fun to spend time with. I've read a few of his other 29 books and most are an interesting ride. I have one on order. N0UU ___ 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] Anybody have suggestions for time related science fair projects?
Hi: Here's some great ideas from Clifford Stoll: https://www.ted.com/talks/clifford_stoll_on_everything?language=en The transcript is available in 27 languages. PS He has an on line business selling Klein Bottles (some with calibration certificates:) http://www.kleinbottle.com/ I got a Chinese Spouting Bowl from him. http://www.prc68.com/I/ChineseSpoutingBowl.shtml -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html ___ 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] Ashtech Z12 question.
Hi Mark: I've found there are two main reasons older equipment stops working. 1. A metal to metal joint that's supposed to be conductive is not. See Hints & Tips: What Goes Wrong: http://www.prc68.com/I/HaT.shtml#Wgw The fix is simply to disassemble, cycle all joints a few times and reassemble. I have a gut feeling that applying oxygen free silicon grease before reassembly might be a real fix, but don't have enough data to make the claim. 2. Capacitors go bad. Electrolytic caps essentially become open circuits and can do that without any indication of a problem. Other times caps fail and cause very noticeable problems for adjacent components. So a visual and nasal inspection is the fist step. An ESR meter is the second step. http://www.prc68.com/I/HaT.shtml#CF -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html Original Message Antenna is good... it is feeding an HP amplified splitter which goes to 7 other receivers. And yes, it died in the middle of a run. I have another Z12 coming from Ebay... -- Rats. Is the antenna known to be good? Is the Z12 providing bias on the antenna cable? Did the Z12 stop tracking right in the middle of the session with no nearby events or configuration changes? ___ 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] WWVB: measuring local 60 KHz noise
Hi Hal: You might want to check the orientation and location of the antenna before digging into more technical areas. It's been my experience there's a lot of AC mains conducted noise at 60 kHz. http://www.prc68.com/I/LF-Ant.shtml#Noise http://www.prc68.com/I/Spec_0002.shtml - 0 to 200 kHz spectrum plot (PS when LORAN-C was on the air) Another source of noise is an LCD screen. Note Wellenbrook Communications suggests placing their loop antenna 100 feet from your house. The loopstick antenna in the UltraLink is a single ferrite rod with nulls off the ends, so orientation is important, not so much that you have to point the maximum at WWVB, but that you don't want to point the null at WWVB. I'm in California and have had to relocate WWVB clocks on walls 90 degrees to where I'd rather have them because of this. http://www.prc68.com/I/Loop.shtml http://www.prc68.com/I/Shadow-Clock.shtml#WT5360U -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html Original Message Review/background: I have an UltraLink 333 WWVB receiver. It didn't work. Several weeks ago. a discussion here mentioned that the phone cable between the main box and antenna needs to be straight through rather than the typical reversed. That was my problem. With the correct cable, the meter shows signal and bounces around such that with practice, I could probably read the bit pattern. But it didn't lock up. That was several weeks ago. I left it running. When I looked last night, it had figured out that it is 2018. I wasn't watching or monitoring, so I don't know how long it took. I assume the problem is noise. Is there any simple way to measure the noise around 60 KHz? How about not so simple? Extra credit for a way that others nuts can reproduce so we can compare the noise at my location with other locations. Can any audio cards be pushed that high? I see sample rates of 192K, but I don't know if that is useful. I'd also like to measure the propagation delays on WWV so a setup for HF that also works down to 60 KHz would be interesting. -- The UltraLink documentation says the display has a slot for a C or H. The C is for Colorado and the H is for Hawaii. Did WWVH have a low frequency transmitter many years ago? The NIST history of WWVH doesn't mention it. My guess is a cut+paste from a version that listened to WWV/WWVH. ___ 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] Yale physicists find signs of a time crystal
Hi: The actual Yale papers are behind a paywall. https://news.yale.edu/2018/05/02/yale-physicists-find-signs-time-crystal "Time crystals, first identified in 2016, are different. Their atoms spin periodically, first in one direction and then in another, as a pulsating force is used to flip them. That’s the “ticking.” In addition, the ticking in a time crystal is locked at a particular frequency, even when the pulse flips are imperfect." But here is some public stuff: https://en.wikipedia.org/wiki/Time_crystal Observation of a Discrete Time Crystal https://arxiv.org/pdf/1609.08684v1.pdf "However, nonequilibrium Floquet systems subject to a periodic drive can exhibit persistent time-correlations at an emergent sub-harmonic frequency7–10. This new phase of matter has been dubbed a “discrete time crystal” (DTC)10,11. Here, we present the first experimental observation of a discrete time crystal, in an interacting spin chain of trapped atomic ions. -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html ___ 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] nuts about position
Hi J: I had a number of survey stakes I placed using a manual transit and tape measure and hired a local surveyor to tell me where they were and also tell me where my GPS antenna was located. He setup a GPS antenna on one tripod and a (Trimble?) combined GPS-total station on another tripod and ran a cable between the two. After some time (tens of minutes or ??) he used the theodolite to sight my stakes and the GPS antenna. I got a report back in a week or so. Total cost a few hundred dollars. I'm in the process of looking at how accurate the GPS is in my new LG G6 phone. -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html Original Message I think to really be confident about a position you really need the dual-frequency data (or that data from a nearby reference station), otherwise you could end up in a situation where you're consistent, but that consistency has a bias. IIRC, anyhow -- I'm not sure how the math actually works out. Anyhow, I play around with PPP stuff on occasion, and the last run I did was in November using the Novatel OEM628 kit that was briefly available for cheap on eBay, and the included 702-GG antenna (which, conveniently, has calibrations available). Running a day's worth of data through CSRS-PPP produced sigmas (95%) of 0.004m latitude, 0.008m longitude, and 0.024m in elevation. I've done some shorter runs since then that appear to fall in that same range ... I really need to do a few more full runs and see what kind of variance there is. At any rate, theoretically you can get ^^^ that close, anyhow. CSRS even takes solid earth tides into account, though I didn't do that because I was never able to figure out which specific type of solid earth tide data I needed. I imagine there's still some issues with any given datum being somewhat imperfect, as far as altitude is concerned, and I don't really know how to correctly deal with that if exact altitude matters. Maybe we should all just agree to use XYZ/ECEF coordinates for everything and give up on this whole altitude thing altogether... ;) (As an aside, I've been tempted to get someone to come professionally survey my antenna and tell me where it _actually_ is, so I could see how well I could actually do with my GPS kit, but I imagine it's pretty expensive -- anyone happen to know what getting that kind of thing done actually ends up costing?) -j ___ 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] nuts about position
Hi Tom: I have a friend who bought a house on a hill so that he could build an observatory with an excellent view of the sky. The telescope mount is the Paramount by Software Bisque. This mount is capable of pointing accuracy measured in a small number of arc seconds. That implies the control software knows the time to a high precision. But there's no "time nuts" clock involved. The control PC computer only has the stock NTP function turned on the in the clock. To get that pointing accuracy he uses TPoint software that models the mechanical errors in the mount. As part of the start up procedure he points to a know star or stars and that sets the clock. I expect that the location of the telescope is determined as part of the TPoint alignment process that looks at a large number of stars. PS We used the gun laying function of the DAGR GPS receiver when laying out the observatory to get a North-South line. http://prc68.com/I/DAGR.shtml#GLS As part of a FireWise community mapping process I'd like to get GPS coordinates of the fire hydrants (Lat, Lon, Ele). Is there a civilian GPS receiver that makes use of WAAS and/or DGPS corrections? -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html Original Message List -- I had a recent query by a researcher who would like to pinpoint the location of his telescope(s) within 0.3 meters. Also (he must be a true scientist) he wants to do this on-the-cheap. He may have timing requirements as well, but that's another posting. So I toss the GPS question to the group. Surely some of you have crossed the line from precise time to precise location? How easy, how cheap, how possible is it to obtain 0.3 m accuracy in 3D position? When we run our GPSDO in survey mode how accurate a position do we get after an hour, or even 24 or 48 hours? And here I mean accurate, not stable. Have any of you compared that self-reported, self-survey result against an independently measured professional result or known benchmark? Do you know if cheap ublox 5/6/7/8 series receivers are capable of 1 foot accuracy given enough time? If not, what improvement would -T models and RINEX-based web-service post-processing provide? It that's still not close enough to 0.3 m, is one then forced to use more expensive multi-frequency (L1/L2) or multi-band (GPS, GLONASS, Galileo) to achieve this level of precision? If so, how cheaply can one do this? Or is the learning curve more expensive than just hiring an survey specialist to make a one-time cm-level measurement for you? Something tells me 1 foot accuracy in position is possible and actually easier than 1 ns accuracy in time. I'm hoping some of you can help recommend solution(s) to the researcher's question or shed light on this interesting challenge. Thanks, /tvb ___ 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] Better quartz crystals with single isotope ?
Hi: I found a perfect quartz ball. It took Stanford many decades to make it. https://einstein.stanford.edu/TECH/technology1.html -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html Original Message Hi: Isotopes of an element differ in the number of neutrons. The chemical reactions of an element are governed by the electrons, which are the same for all isotopes, so chemical means can not be used to separate the isotopes. There are a number of ways of making the separation, for Uranium see: https://en.wikipedia.org/wiki/Clinton_Engineer_Works#Facilities It's not clear to me how the isotopes of water are accounted for in it's physical properties. Have these been refined and defined for each isotope? This may be important since the properties of water show up a lot as the basis for other definitions. https://en.wikipedia.org/wiki/Isotopes_of_hydrogen https://en.wikipedia.org/wiki/Isotopes_of_oxygen PS One of the names of the company I worked for was FEI Microwave. There was a rumor that the funder of that company had a bunch of very special quartz in the vault and that crystals cut from that material had better phase noise than off the shelf crystals hence he had an advantage over other vendors. http://prc68.com/I/Aertech.shtml#Names ___ 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] Better quartz crystals with single isotope ?
Hi: Isotopes of an element differ in the number of neutrons. The chemical reactions of an element are governed by the electrons, which are the same for all isotopes, so chemical means can not be used to separate the isotopes. There are a number of ways of making the separation, for Uranium see: https://en.wikipedia.org/wiki/Clinton_Engineer_Works#Facilities It's not clear to me how the isotopes of water are accounted for in it's physical properties. Have these been refined and defined for each isotope? This may be important since the properties of water show up a lot as the basis for other definitions. https://en.wikipedia.org/wiki/Isotopes_of_hydrogen https://en.wikipedia.org/wiki/Isotopes_of_oxygen PS One of the names of the company I worked for was FEI Microwave. There was a rumor that the funder of that company had a bunch of very special quartz in the vault and that crystals cut from that material had better phase noise than off the shelf crystals hence he had an advantage over other vendors. http://prc68.com/I/Aertech.shtml#Names -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html Original Message Single isotope diamond is 50% better thermal conductivity of normal diamond. It has been used in laser optics and thermal transfer applications (semiconductor heatsinks). I think the highest reported thermal transfer rate used isotopically pure diamond etched with micro-fluidic channels fed with coolant. GE makes the diamond material... it was developed as part of Reagan's Star Wars project. Isotopically pure silicon has 60% better thermal conductivity than natural silicon. Isotopically pure platinum has been used in RTD temperature sensors. ___ 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] Citizen Concept watch: Ultraprecise Eco-Drive movement Calibre 0100
Hi: Claims +/- 1 second per year and is autonomous. Uses an AT cut crystal at 8,388,608 Hz (2^23 ) and has a custom temperature compensation for each watch. Solar powered, and the hands stop if the watch is in the dark to save power. http://www.citizenwatch-global.com/100th/product/calibre0100/index.html -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html ___ 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] Help improving impedance measurement by having a better clock
Hi Daniel: If you're concerned with accuracy of impedance measurements you might want to spent a lot of time studying "The Impedance Measurement Handbook", it's the bible for this. The way the measurement is made has a huge impact on the accuracy. For example using a vector network analyzer to measure an impedance that's not near 50 Ohms causes poor results. http://prc68.com/I/Z.shtml#KeyDocs For frequencies low enough to use 4 Terminal Pair, that's the way to go. http://www.prc68.com/I/HP4274_4275_LCR.shtml#MeasMtd -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html Original Message I´m a long time time-nuts lurker (I posted here just a dozen times). I make a few impedance measurement systems for material analysis (i´m a single man shop doing custom hardware for clients). Usually they´re based around a STM32F4 / F7 microprocessor: DAC generates sine signal (1-400KHz), ADCs measure them back, a few calculations later we have modulus / phase. I always used internal ADCs and DACs (12 bits each). I now want to use external ADCs and DACs with more bits to push the limits, but i´m afraid that the poor performance of the STM32 PLL that drives the clock will get in the way, so I plan to drive the "load" of both DAC and ADCs from an external signal derived from a TCXO using a clock divider. To get some sense of how much things are improving (or not) I need to somehow measure these clocks and get a meaningfull measurement about how good (or bad) they are. The tools I have are a Hameg HM8123 with a 10MHz OCXO I shoehorned inside and a Picotest U6200A with original OCXO. I can log period information from both using serial/USB port. I can make a histogram of the data. I don´t have any better idea about what to do and would like to hear from you :) Daniel ___ 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] quartz / liquid nitrogen
Hi Mark: When Aetech started to make their own Tunnel Diodes there was a problem with the neck breaking. Note they were made by alloying a ball of metal onto a highly doped chip, bonding from the lip of the ceramic package to the ball then on to the opposite lip, then etching the chip away leaving something that in cross section looked like a mushroom. The neck was a few microns wide and often broke. The fix was to epoxy a glass rod on either side of the chip, between the metal bottom of the ceramic pill package and the bonding wire. The glass was chosen to have a CTE that matched the die. That solved the broken neck problem. http://prc68.com/I/Aertech.shtml#Prod -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html Original Message And you want your semiconductors to be in ceramic/lided packages with the bond wires flapping in free air. Bond wires embedded in epoxy like to break... don't ask how I found this out ;-) ... it brings back bad memories... and makes bad memories... Quantum chips have very elaborate/specialized bonding to survive liquid helium... even with that, thermal cycling still breaks them. ___ 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] quartz / liquid nitrogen
Hi Tom: Put the dry ice in acetone to the lowest temp. -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html Original Message Has anyone tried running a quartz oscillator at liquid nitrogen temperatures: -196 C (-321F, 77K)? It's probably impractical commercially, but maybe something of value to a time nut. Would that dramatically lower temperature improve phase noise & short-term performance? Is there a crystal cut that could be optimized for 77 K instead of ~25 C (room) or 60 C (oven)? If not Nitrogen, how about dry ice (-109F -78C)? /tvb ___ 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] GPS System Message (was: TV Signals as a frequency reference)
Hi Mark: I don't think the SV Messages are related to Over The Air Rekeying (OTAR) since they don't have enough characters. My guess is that they are a modern form of the Emergency Action Message (EAM). Here's a screen shot of a DAGR GPS receiver showing the first couple of messages as of 2 pm pacific time 3/31/2018: http://www.prc68.com/I/DAGR.shtml#SV_Messages https://en.wikipedia.org/wiki/Over_the_Air_Rekeying https://en.wikipedia.org/wiki/Emergency_Action_Message -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html Original Message Or on the GPS/GNSS signals... I was verifying Lady Heather's support for the old SV6/Palisade/Acutime receivers and came across a mention of the "GPS System Message" command. It is requested by TSIP packet 0x28 and returns packet 0x48. Newer Trimble receivers (like the Resolution-T don't seem to support the 0x28/0x48 messages. It is only mentioned in the SV6 docs. The system message is a 22 character ASCII string embedded in the GPS navigation messages. If you dig into the GPS ICD docs it says it is used like a "bulletin board" for GPS users and can be a plaintext or encrypted message. They currently seem to be encrypted... perhaps a way to distribute P-code keys? I wonder if any of the newer GNSS sats have some hidden goodies in the signals? When sent to the SV6, you get a single response. When sent to a Thunderbolt, you get 31 messages (mostly all the same). I think the different messages are due to delays in the ground control system updating the satellites or the receiver not tracking particular satellites between updates. Here a couple of responses from a Thunderbolt: # GPS system message:X4W-BZXE3/HPU77G49PU1V # GPS system message:X4W-BZXE3/HPU77G49PU1V # GPS system message:X4W-BZXE3/HPU77G49PU1V # GPS system message:X4W-BZXE3/HPU77G49PU1V # GPS system message:X4W-BZXE3/HPU77G49PU1V # GPS system message:Z9Mx69BOC1 Lx+:LR3X2 Q # GPS system message:Z9Mx69BOC1 Lx+:LR3X2 Q # GPS system message:X4W-BZXE3/HPU77G49PU1V # GPS system message:X4W-BZXE3/HPU77G49PU1V # GPS system message:Z9Mx69BOC1 Lx+:LR3X2 Q # GPS system message:X4W-BZXE3/HPU77G49PU1V # GPS system message:X4W-BZXE3/HPU77G49PU1V # GPS system message:X4W-BZXE3/HPU77G49PU1V # GPS system message:X4W-BZXE3/HPU77G49PU1V # GPS system message:X4W-BZXE3/HPU77G49PU1V # GPS system message:X4W-BZXE3/HPU77G49PU1V # GPS system message:X4W-BZXE3/HPU77G49PU1V # GPS system message:X4W-BZXE3/HPU77G49PU1V # GPS system message:X4W-BZXE3/HPU77G49PU1V # GPS system message:X4W-BZXE3/HPU77G49PU1V # GPS system message:X4W-BZXE3/HPU77G49PU1V # GPS system message:X4W-BZXE3/HPU77G49PU1V # GPS system message:X4W-BZXE3/HPU77G49PU1V # GPS system message:X4W-BZXE3/HPU77G49PU1V # GPS system message:X4W-BZXE3/HPU77G49PU1V # GPS system message:X4W-BZXE3/HPU77G49PU1V # GPS system message:X4W-BZXE3/HPU77G49PU1V # GPS system message:X4W-BZXE3/HPU77G49PU1V # GPS system message:X4W-BZXE3/HPU77G49PU1V # GPS system message:X4W-BZXE3/HPU77G49PU1V # GPS system message:X4W-BZXE3/HPU77G49PU1V # GPS system message:E:S4.A2'3'A65/C5M8 UQO # GPS system message:E:S4.A2'3'A65/C5M8 UQO # GPS system message:E:S4.A2'3'A65/C5M8 UQO # GPS system message:E:S4.A2'3'A65/C5M8 UQO # GPS system message:E:S4.A2'3'A65/C5M8 UQO # GPS system message:5FT16X78CN53GVWVF1/8BW # GPS system message:5FT16X78CN53GVWVF1/8BW # GPS system message:E:S4.A2'3'A65/C5M8 UQO # GPS system message:E:S4.A2'3'A65/C5M8 UQO # GPS system message:5FT16X78CN53GVWVF1/8BW # GPS system message:E:S4.A2'3'A65/C5M8 UQO # GPS system message:E:S4.A2'3'A65/C5M8 UQO # GPS system message:E:S4.A2'3'A65/C5M8 UQO # GPS system message:E:S4.A2'3'A65/C5M8 UQO # GPS system message:E:S4.A2'3'A65/C5M8 UQO # GPS system message:E:S4.A2'3'A65/C5M8 UQO # GPS system message:E:S4.A2'3'A65/C5M8 UQO # GPS system message:E:S4.A2'3'A65/C5M8 UQO # GPS system message:E:S4.A2'3'A65/C5M8 UQO # GPS system message:E:S4.A2'3'A65/C5M8 UQO # GPS system message:E:S4.A2'3'A65/C5M8 UQO # GPS system message:E:S4.A2'3'A65/C5M8 UQO # GPS system message:E:S4.A2'3'A65/C5M8 UQO # GPS system message:E:S4.A2'3'A65/C5M8 UQO # GPS system message:E:S4.A2'3'A65/C5M8 UQO # GPS system message:E:S4.A2'3'A65/C5M8 UQO # GPS system message:E:S4.A2'3'A65/C5M8 UQO # GPS system message:E:S4.A2'3'A65/C5M8 UQO # GPS system message:E:S4.A2'3'A65/C5M8 UQO # GPS system message:E:S4.A2'3'A65/C5M8 UQO # GPS system message:E:S4.A2'3'A65/C5M8 UQO I wonder how many secret services are parasites on the commercial TV transponders ___ 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] Ultralink
Hi John: The U4226B chip operates at very high impedance levels in order to minimize battery drain in its main application, battery powered clocks. So some sort of buffer is needed on all the output pins. The 333 model, with the analog meter, was made for the folks working for WWVB as a way for them to know the transmitter was on the air. http://www.prc68.com/I/timefreq.shtml#WWVBrcvr http://www.prc68.com/I/Loop.shtml (WWVB) -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html Original Message On 03/30/2018 03:39 AM, Hal Murray wrote: t...@leapsecond.com said: I updated http://leapsecond.com/museum/ulio/ with more manuals, and many exterior / interior photos of the 301 module. Thanks. My 301 says it is a 30TH Rev-A - mostly through hole parts. Same layout. Mine is the same. Circuit is very simple. The 20 pin IC is the U4226B receiver chip and it has two external 60 kHz filter resonators. The 8 pin DIP is a TLV2770C op amp which seems to be a buffer to drive the S meter from the very high impedance AGC test point on the receiver chip. And I am guessing that the 2N3904 transistor is a buffer for the time code output. The modular cable connecting the receiver to the decoder is wired straight through, not reversed as most telephone cables are. My fear is that someone (like me) might at one point have used a reverse cable and thus put reverse polarity on the board; I don't see any reverse power protection. Later today I'll tap into the four conductors on the cable and see what signals I see on them, and also look for signs of life on the receiver chip. BTW -- Donald Resor pointed me to UTSource which shows several Chinese vendors as having them in stock. I get nervous about whether they are the real thing or not, but will probably order a couple just in case. The chip is a 20 pin TSSOP package, which isn't too hard to rework but before putting hot air on the receiver board there are one or two surrounding parts one would want to remove to avoid collateral damage. John ___ 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] Putting the clock forward at Avebury Stone Circle
Hi: The DST adjustment in the UK: http://www.ntsouthwest.co.uk/2014/04/putting-the-clock-forward-at-avebury-stone-circle/ “Obviously Stone Age man didn’t have daylight saving, so twice a year we have to move one of the stones.” said Hilary Makins, National Trust Head Ranger. -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html ___ 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] Heathkit GC 1000 Most Accurate Question
Hi: Bill Mine needed pretty much all the electrolytic caps replaced. http://prc68.com/I/HeathkitGC1000.shtml -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html Original Message I own a Heathkit GC 1000 Most Accurate Clock. It's in terrific shape but not used for many years. It has stopped locking up to WWV and sometimes freezes up. Can any of our "nuts" repair it? Anyone want to buy it? Bill, w1...@aol.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] HP 105B: Modern replacement for NiCad battery pack?
Hi Ulf: There's another problem with switching to Ni-MH and that's related to the heat generated when charging them. You can charge Ni-Cad batteries without monitoring the pack temperature, but with Ni-MH cells you must monitor the pack temperature. I would suggest avoiding the Ni-MH option. Either: 1. Just use modern Ni-Cad cells, no memory and much higher capacity, no change to the charger, or . . 2. Update to one of the Li-xxx chemistries with a totally new charger. These batteries have much lower self discharge rates and higher energy density. -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html Original Message Gentlemen, I may have asked this question before... I am looking for a modern replacement for the NiCadbattery pack used in the HP 105B. One such 105that I salvaged have been standing on a shelf with thebatteries "happily boiling away". So, what kind of chemistry would be possible to usewithout to much re-design of the charging circuitry? Ulf Kylenfall SM6GXV ___ 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] Helmholtz Resonator and other Maintained Oscillators
Hi: I'm watching this hour lecture on YouTube by the Naval Postgraduate School (NPS) for information about Helmholtz Resonators, but recommend it here because there's excellent demonstrations of time related ideas. Helmholtz Resonator and other Maintained Oscillators https://youtu.be/y86QhzesYok -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html ___ 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] Fast Rise/Fall Time Pulser
Hi Larry: How does it work. When I was working with microwave semis it was either a tunnel diode or a Step Recovery Diode. -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html Original Message There has been discussion recently about generating fast rise/fall time pulses by various means. Here is a link to a Leo Bodnar device that will provide <40 ps rise/fall time, 50% duty cycle, 10 MHz pulses: http://www.leobodnar.com/shop/index.php?main_page=product_info=124_id=295 This is built on a small PWB with integral BNC connector, powered by 5 vdc through a USB B connector; a trigger output is provided. Price is US$68. I've ordered one of these for testing. Is anyone here using one of these? ___ 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] Looking for Austron manual
Hi Francis: http://www.prc68.com/I/A2100F.shtml#Man -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html Original Message I recently obtained an older Austron 1210 and am looking for a manual. I don't have the nameplate but the front panel is inscribed "Austron 1210 Crystal Clock", with no letter suffix. The battery tray cover has a date of "August 12 1985" stamped on it, and it has the analog clock. Unfortunately it is in rather rough shape and it looks like somebody attempted to modify it in some way. Apparently the oscillator has been replaced; it's now an Austron 1150 with a date of 3/85 on it. I'd really like to restore it as close to original condition as possible, or at least working properly. If anyone has a manual for this version or a pointer to it I'd really appreciate it. I have the manual for the "D" version but apparently this is considerably different. Thanks in advance for any help! Francis Grosz, K5FBG ___ 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] Thunderbolt - trouble locking with some types of antennas
Hi Jerry: The Trimble is the oldest mass produced GPS receiver I know of and because the early receivers used high gain antennas it seems that Trimble kept that idea for the newer designs. They like about 41 dB gain between the antenna and the input to the receiver. http://www.prc68.com/I/Trimpack.shtml#Ant Newer designs probably place that gain in the front end rather than at the antenna. But having around 20 dB of gain at the antenna gretly decreases the effect of feed line loss on noise figure. -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html Original Message Due to access problems, I run my Thunderbolt with a Symmetricom 58532A antenna placed indoor near a window facing South cant get much worse but most of the time it will be locked onto 3 or 4 satellites.I recently bought a www.leobodnar.com <http://www.leobodnar.com> GPSDO for my SDR ham radio setup. I was very surprised to find that this minimalist GPSDO using a small patch antenna with internal LNA placed near my window had satellite & PPL lock within a few seconds. It requires 3-4 satellite locks for its PPL. However, when I attached the patch antenna to my Thunderbolt satellite signal strength were zero or minus for all satellites. The specs for the patch antenna are listed below. I would appreciate any advice understanding this behavior. Jerry NY2KW Center Frequency 1575.42MHz±3 MHz V.S.W.R 1.5:1 Band Width ±5 MHz Impendence 50 ohm Peak Gain >3dBic Based on 7×7cm ground plane Gain Coverage >-4dBic at 90°<0<+90°(over 75% Volume) Polarization RHCP LNA/Filter LNA Gain (Without cable) 28+/-3dB Noise Figure 1.5dB Typ. Filter Out Band Attenuation (f° =1575.42MHz) 7dB Min f0+/-20MHZ 20dB Min f0+/-50MHZ 30dB Min f0+/-100MHZ V.S.W.R <2.0 DC Voltage 2.7V/3.0V/3.3V/5.0V/3.0V to 5.0V/other DC Current 5mA /11mA/15mA Max ___ 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] HP-113AR vs. BR differences?
Hi Jeremy: The HP Journal for Nov - Dec 1959 has the HP 113 AR as the cover feature. www.hpl.hp.com/hpjournal/pdfs/IssuePDFs/1959-11.pdf Photo of some HP T stuff including the 113 AR http://prc68.com/I/TF_rack.html -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html Original Message I'm trying to understand the differences between the HP-113AR and 113BR "Frequency Divider and Clock." From the pictures, the AR lacks a front-panel BNC for the clock 'tick,' having only three BNCs instead of the four that the BR version has. Didier's site has a manual for the 113BR but I've not yet found one for the AR. There was a discussion here in 2007, in which a David Forbes of Tucson, AZ wrote that he had a 113AR manual. Any information or leads would be appreciated. Jeremy Sent from my iPad 4 ___ 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] Papers on timing for lunar laser ranging
Hi: The Quantic Timing GPS receiver makes use of patent 5440313which results in a 48 bit DAC. How does this idea compare? http://www.prc68.com/I/Q5200.shtml https://www.google.com/patents/US5440313 PS the above patent cites 4582434 i.e. the Heathkit GC1000 HFDO. -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html Original Message On Sat, 8 Jul 2017 11:42:44 -0700 Tim Lister <lister...@gmail.com> wrote: Forgive the ignorance, but why is there a large disparity between ADC and DAC capabilities ? For example, Linear Technology sell a 24 bit ADC for ~$7 but an 18 bit DAC is $30-50... Much simplified, it boils down to it being easier to measure voltage differences by averaging than keeping a voltage constant. E.g. in those >20bit ADC's you will usually find a delta-sigma ADC, usually 3rd to 5th order with a 1.5 to 5 bit ADC/DAC inside. The ADC and DAC can be laser trimmed to be in the order of 0.1% of their ideal values. With a few additional tricks you can get the most of the remaining non-linearity out. These tricks also help to remove errors due to DC-offsets in the signal path. But the biggest improvement comes from averaging over many "samples" to get the white noise out. If you look at the usual sample rates at which those ADC reach their "full" performance, it is around 1-30 (output) samples per second. On the other hand, on a DAC you need to keep the output voltage stable. You can do the same delta-sigma approach as with the ADC with much the same result, but you have one big problem: it is not easy to build an analog low pass filter that has a corner frequency down at 10Hz. This means, you have to work at a much higher frequency to have a low pass filter that can be realized (let's say 1kHz if you are building a discrete filter, higher if it's integrated). But that means that you have several orders of magnitude more (white) noise. Additionally, a lot of people expect to do a couple of 1000 samples per second at least, to have a usefull DAC. But that contradicts the need to have a narrow band low pass filter to get the noise out. Attila Kinali ___ 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] DS3231 drift over a year
Hi Pete: AFAICR the DS3231 has a software fine tune. Did you set that before the test? -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html Original Message Hi all, I use some DS3231 temperature-compensated real-time clocks with some Raspberry Pis, particularly those that might not always have internet access. About a year ago I wrote some code [1] to characterize the behavior of these particular chips using my Thunderbolt as a reference, using the Arduino/atmega328 as a glorified counter. As a somewhat longer-term test, I set the time on one of the DS3231s to the correct time using GPS-synced NTP on one of the Pis, then set the whole thing on the shelf for a bit over a year and forgot about it. If relevant, the only power source was the CR2032 battery. I checked it today, and the clock had drifted 16 seconds since June 6th of 2016 to now. That works out to around 0.5 ppm drift over that time. The chip is specced to +/- 2ppm. Not bad for a cheap module of potentially dubious provenance from eBay. For those who are curious, I'd be happy to provide a link to the specific item I purchased; contact me off-list for details. Cheers! -Pete [1] https://github.com/heypete/Frequency_Counter_32kHz ___ 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] WWVB & Eclipse
Hi: There's a massive experiment relating to the strength of WWVB and a transmitter in Dixon California. https://www.washingtonpost.com/news/speaking-of-science/wp/2017/07/12/a-massive-atmospheric-experiment-is-planned-for-august-solar-eclipse/?utm_term=.4d7101b869f6 http://eng.umb.edu/~eclipsemob/index.php <http://eng.umb.edu/%7Eeclipsemob/index.php> http://www.hamsci.org/sites/default/files/publications/2017_IES_Liles.pdf This article says Dixon may transmit at 55.1 and 135.95 kHz. The EclipseMob receiver works with a smart phone acting as an SDR. as well as the source of it's position and the date-time of observation. There is a parallel study based on ham radio WSPRNet and Reverse Beacon Network. http://hamsci.org/ Is there a study based on GPS observations? -- Have Fun, Brooke Clarke, N6GCE http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html ___ 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] Anderson PowerPole (was Charles Wenzel GPSDO)
Hi Chris: Yes. Just looked on eBay and in under a minute found Item 231877388026. 11.1 V 6.6 AH with a label rate of 75C, but the eBay ad says 75C-150C. So it will produce between 495 and 990 Amps. The stock connector is the EC5, which is needed for this kind of current. It's the connector used on the devices which used to be advertised as car starters, but now are sold as battery chargers. http://www.prc68.com/I/PowerBankJumpStarter.html#Photos -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html Original Message 18 volt nominal 8,000 mAH LiPo battery ___ 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] Power connectors continued
Hi: A few tips on Power Poles. 1. Super Flex wire works very well. It's typically made of of 44 AWG strands. For PCB mounting a single strand can be used for mechanical rigidity. 2. There's no rule that all the current has to be carried by a single terminal The M455-1 power supply uses many pins in parallel on the 24 Volt 50 Amp output Amphenol connector where 7 and 8 pins are wired in parallel rather than use a connector with a couple of pins rated at 50 or more Amps. http://www.prc68.com/I/M4551.shtml 3. Note the "24 Volt" version of the Power Pole connector. -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html Original Message Bob, look to this spec. data from Amphenol found @ Mouser as example: Current Rating: power Contacts: 55 Amperes (per contact) Signal Contacts: 5 Amperes (per contact) Contact Resistance: Power Contacts: .25 milliohms max Signal Contacts: 20 milliohms max Insulation Resistance: 5000 Megohms DWV: 1500V DC Operating Temperature: -40°C to +105°C http://www.mouser.com/ds/2/18/LCC17_BRO-44772.pdf ok, for shure more expensive (LCC17-A3W3SM-2N0, <http://www.mouser.de/ProductDetail/Amphenol-Commercial-Products/LCC17-A3W3SM-2N0/?qs=sGAEpiMZZMv3qGlUeJulRG8yb3Pdn%252bYMJfJuKobi5wY%3d> $ 9.45 per con. one side, solder connection) http://www.mouser.com/ds/2/276/Mixed_Layout-472362.pdf e.g. for crimped contacts Not of interest? But sorry, even being very interesting, I think we should not stress too much the term 'time' in this discussion here ;-) . kind regards Arnold, DK2WT Am 23.06.2017 um 01:33 schrieb Bob kb8tq: Hi You can get and use PP’s at 30 to 50A in a 12V circuit without frying them or the cable they are attached to. Doing the same with a “Cannon” connector is not at all easy ….You can also bump up to the larger PP’s and get into a couple of hundred amps. Bob On Jun 22, 2017, at 6:54 PM, Arnold Tibus <arnold.ti...@gmx.de> wrote: Hello, I can second Magnus and want to throw in some more details. Cannon, Deutsch, Bendix, Souriau, Matrix, Amphenol, etc. etc. are (big) companies manufacturing all kind of connectors and are n o t connector type designations! Important are the type numbers of the manufacturer or higher level specification numbers. We used in the aircraft and spacecraft business naturally the military (MS-) numbers listed in the MIL-QPL (or eg. for Spacelab with GSFC spec. no). Most types of connectors are under these numbers available from different manufacturers, of course with different manufacturer in house part numbers. Attention: the 'same' connectors may be bought w/o the Mil.-spec. sheets with somewhat lesser quality. Important details are the max. mating number, the contact resistance (e.g. 20 mOhm) and the max. continuous current, max. Voltage, vibration resistance and reliability etc. Of course, this makes good connectors somewhat 'expensive'. Hirel and non-magnetic gold plated D- subminiture type connectors do survive e.g. the rocket launch phase (high vibrations), vacuum and low temperatures and are still used for space projects. The D-sub series of connectors was introduced by Cannon in 1952. They are still available as standard, hirel, and non-magnetic versions. The contacts were machined contacts forcrimping or soldering connection and made of massive copper with gold finish. (more see e.g. https://en.wikipedia.org/wiki/D-subminiature). Example for the standard 9 pin connector designation (crimp): DEMAM-9S and DEMAM-9P. Today are a big number of companies producing equivalent types. Cheap ones are equipped with contacts made of sheetmetal. Nobody should expect then the same spec. values as reliability, mating numbers, contact power rating etc. It is up to the designer of a product to be informed and select the right quality device for his product ... I hope I could enlight a bit the connector selection and nomenclature point. regards, 73 Arnold, DK2WT Am 22.06.2017 um 21:10 schrieb Magnus Danielson: Hi, The second connect has been called "Cannon" and XLR, and is not generally recogniced as XLR, which is the product range name. Naming of the first connector as "Cannon" is at least for me and many others confusing. This is a good example how vendor name for a connector type is not a good thing. The first connector is a circular MIL-STD connector (don't remember the correct notation), and this is a product available from ITT Cannon as well as AMP. Cheers, Magnus On 06/22/2017 08:42 PM, Mark Spencer wrote: Sorry if I have caused any un due confusion thru my perhaps incorrect use of the terms "cannon" and "XLR." The green connector with 4 separate female contacts is what I perhaps in correctly referred to as a "cannon" connector. The silver connector with 3 separate female contacts was what I perhaps incorrectly referred to as a "XLR" connector.
Re: [time-nuts] Anderson PowerPole (was Charles Wenzel GPSDO)
Hi: The 45 Amp terminals come in two versions, one being " Hi Détente" p/n: 201G1H that is much stronger although I've never had a pull apart problem. -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html Original Message Wes, Don, I am quite surprised at the negative reaction to Anderson Power Pole connectors. I have found them the best DC connector out there. I have used them for a decade or two for all my DC feeds and have never had a problem: in my home lab, my car, even for my laptop charger. They are inexpensive, reliable, genderless (hermaphroditic) and easy to crimp. I use them for my 5V, 12V, 24V, and 48V supplies as well as my DC backup systems. What on earth are you doing with them that causes them to disconnect? I mean, they are not meant for towing or lifting or rappelling. For critical applications there is a plastic gizmo that keeps them mated; or just use a square or figure 8 knot on the cables. /tvb ___ 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] GPS splitter
Hi: I just use a resistor. http://www.prc68.com/I/DAGR.shtml#PS and here is the Cable TV power divider were Type-F DC blocks are added to all but one of the output ports. http://www.prc68.com/I/4GPS.shtml -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html Original Message Hi Hitting the inductance required is relatively easy. Doing so and not hitting self resonance is a bit more tricky. Even a zero ohm reactance likely will work ok (in series with a 150 ohm resistor). It’s tough to know what you have done without a network analyzer. It is even possible that your resistor has enough stray C to mess things up. Of course it might also have enough stray L to get you back in business. A somewhat less critical approach is to use ferrite beads on both sides of the resistor. They generally are a bit less critical (= more likely to do what the data sheet claims). The trick there is to find some that are set up to work at L band …. they aren’t common in my junk box. Bob On Jun 21, 2017, at 4:16 PM, Attila Kinali <att...@kinali.ch> wrote: On Wed, 21 Jun 2017 15:03:54 -0400 Bob kb8tq <kb...@n1k.org> wrote: The typical answer is: The largest one I could that 1) Would handle the short circuit current expected and 2) was self resonant at or above 1.6 GHz. I found out, by experiment, that any "large enough" inductance is ok. A simple "a few dozen windings of AWG30, air core and a tiny bit of epoxy to keep the windings apart, yet stable" does the trick quite well. At least it does for the bias-T I used it in. As a rule of thumb, at the frequency you are using it, the inductor should have an impedance much larger then the 50Ohm. And for 1.5GHz you get there pretty quickly. E.g. 20-30 windings on 3mm spread to a length of 20mm give you something in the order of 150 to 350nH, which translates to 1k5 to 3k5 impedance at 1.5GHz. I recommend reading [1] and [2] for the design of bias-T's (there are probably better sources, but these are those that I stumbled upon, some time ago) Attila Kinali [1] "Design of Bias Tees for a Pulsed-Bias, Pulsed-RF Test System using Accurate Component Models", by Baylis, Dunleavy, Clausen, 2006 http://www.microwavejournal.com/articles/3912-design-of-bias-tees-for-a-pulsed-bias-pulsed-rf-test-system-using-accurate-component-models?v=preview [2] "Wideband Bias Tee". by Johnson, 2008 http://wb9jps.com/Gary_Johnson/Bias_Tee_files/Bias_Tee_Design_V2R.pdf -- You know, the very powerful and the very stupid have one thing in common. They don't alters their views to fit the facts, they alter the facts to fit the views, which can be uncomfortable if you happen to be one of the facts that needs altering. -- The Doctor ___ 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] Charles Wenzel GPSDO
Hi Chuck: I'd replace the push on DC power connector with a high force Power Pole. I can't count how many times one of these push on connectors has worked itself loose. http://www.prc68.com/I/PowerPole.shtml -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html Original Message I have been waiting for Charles Wenzel to get around to designing and building a GPSDO. Well, he has done it now and you can see it at <http://www.techlib.com/electronics/GPSstandard.htm>. Any thoughts on the design relative to more conventional ones?? Chuck Burch ___ 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] Plate Tectonics was: GPS Antenna on Tower.
Hi Attila: I have a web page devoted to finding true North. http://www.prc68.com/I/North.shtml There are many ways. Here's on that uses the north star. The first step is to sight the North Star (assuming you are in the Northern hemisphere. But the North star currently is at: dec: +89°15' 51" R.A.: 2h 31m 49s This means that when the sidereal time is 2h 31m 49s it's exactly North and then again after 12:00:00 hours sidereal time pass it's again exactly North. Any star can be used with this method, but the closer the star is to 90 deg dec the better from a geometry perspective. -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html One thing I still haven't understood is, how these transit instruments were "calibrated" and placed exactly on a north-south line. All fascinating stuff Definitely! Attila Kinali ___ 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] CRT for Tracor 527A
Hi: Yes, there are Cathode "Rejuvenators" that can sometimes give a CRT some more lift. This is a problem with all test equipment that uses CRTs. There are LCD replacements for the CRT in some HP equipment, like the 8566 SA. -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html Original Message Hello to the group. I was not going to comment on the thread. But realized I should. A caution on CRTs is that if they have been around a long time they may have very poor emissions. Even if new. Cathode pollutes over time. Just saying don't be to surprised if you don't get what you paid for. Best of luck to you. Regards Paul WB8TSL On Tue, Jun 20, 2017 at 5:12 PM, Pete Lancashire <p...@petelancashire.com> wrote: Not rare but uncommon. I gave the one I have away a couple years ago. Ask on a few of he military/boatanchor lists, I've had pretty good luck. -pete On Tue, Jun 20, 2017 at 2:01 PM, David C. Partridge < david.partri...@perdrix.co.uk> wrote: Trying a long shot here, I'm looking for a 1" CRT type 1EP1 (or 1EP11, or?) for a Tracor 527A Frequency Difference Meter. I did spot some on eBay but the vendor had a rather high opinion of their worth :) at over 300 dollars Anyone got one to spare? Thanks Dave ___ 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.
[time-nuts] Plate Tectonics was: GPS Antenna on Tower.
Hi Bryan: The first data on tectonic plate movement came from the Latitude Observatories. The Longitude problem was solved fairly quickly by Harrison's clocks but the uncertainty of an observatories latitude because of wobble of the pole took much longer and was addressed by a hand full of Latitude Observatories all at 39 deg 8 min North, and I'm lucky to have one in my town. http://www.prc68.com/I/UkiahObs.shtml Note this is more like an extremely accurate surveying instrument than a telescope for star watching. We will be having star parties since it's summer and the sky here is dark enough to see the Milky way. -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html Original Message I have wondered how geologists are able to measure tectonic plate movements in the earths surface to a couple cm's when the sensors from what I see/read they are nothing more than sensors in concrete boxes?. I believe they use various technologies such as Very Long Baseline Interferometry<http://www.see.leeds.ac.uk/structure/dynamicearth/plates_move/active_tectonics/vlbi.htm> (VLBI) and Satellite Laser Ranging<http://www.see.leeds.ac.uk/structure/dynamicearth/plates_move/active_tectonics/slr1.htm> (SLR) All fascinating stuff -=Bryan=- From: time-nuts <time-nuts-boun...@febo.com> on behalf of Thorbjørn Pedersen <thorbjorn.peder...@ikm.no> Sent: June 19, 2017 9:42 PM To: time-nuts@febo.com Subject: Re: [time-nuts] GPS Antenna on Tower. http://www.sp.se/en/index/resources/GNSS/Sidor/default.aspx [http://www.sp.se/sv/index/resources/GNSS/PublishingImages/pelare.jpg]<http://www.sp.se/en/index/resources/GNSS/Sidor/default.aspx> GNSS-equipment - SP<http://www.sp.se/en/index/resources/GNSS/Sidor/default.aspx> www.sp.se GNSS-equipment RISE has equipment for GNSS (Global Navigation Satellite Systems) for applications in Time and Frequency, Positioning and Atmospheric Studies. Have a look at the best receiving antenna I know about. The tower must have cooling tubes coiled around it because of the sun heating one side will make it bend away from the sun, and turn this way all day. The cable and doom is also temperature controlled. Best Regards Thorbjørn W. Pedersen ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts time-nuts Info Page - American Febo Enterprises<https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts> www.febo.com time-nuts is a low volume, high SNR list for the discussion of precise time and frequency measurement and related topics. To see the collection of prior postings to ... 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] HP E1938
Hi Tom: I have some info on this at: http://www.prc68.com/I/HPE1938.shtml -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html Original Message I purchased one of these HP E1938 OCXO recently on eBay but have not yet received it. Is that special D-Submin connector a receptacle-shell, pin contact version? Will a standard plug-shell, socket contact 25-pin D-Submin fit it? Hi, I'll cc the group here since we may get some useful comments. I'm not exactly sure what you mean. The E1938A oscillators that I've seen and tested look like this: http://www.leapsecond.com/museum/e1938a/ And those can be interfaced with a simple D-sub DB25 connector on the PCB. For connections, see that page, or any number of postings about the E1938 in the time-nuts archives. Note that on eBay there are at least three variations of E1938A oscillator. The item#'s below are just random search picks (I have no affiliation with any buyers or sellers) and I also know not all surplus refurbished surplus recycled surplus stuff works. But we do this because when they did work, they are sometimes totally amazing. 1) There's the bare "puck" alone, as in http://www.ebay.com/itm/290829077542 -- and I have no idea where one would start with that item since all the support circuitry on the PCB would have to be re-created by hand. 2) There's the integrated PCB assembly, as in http://www.ebay.com/itm/181043193416 -- which is more like what I tested. 3) There's the full instrument version, as in http://www.ebay.com/itm/171293069062 -- which is most likely to work, or be less hacked up, or dented, or salvaged, or rusted. It even has all the connectors and power supplies, and GPS, etc. If any other time nuts have experience with each of these methods to obtain a E1938 oscillator, please let us know. Thanks, /tvb ___ 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] Cesium tube magnets
Hi Dave: It's very hard to get a high magnetic field, even using modern magnets. Here's one attempt: http://www.prc68.com/I/DCGaussmeter.html#PM The best way to use a cone to concentrate the field. I expect modern magnets have stronger fields than those from Cs tubes. -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html Original Message h oooh I want a set. ! any idea how many gauss? Dave On 4/8/2017 8:31 PM, cdel...@juno.com wrote: Here are some magnets from an HP Cesium tube. It shows one pair of state selection magnets, (there are two pairs in each tube), and the magnet for the ion pump. Cheers, Corby ___ 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] Car Clock drift - the lowly 32kHz tuning fork crystal specs
Hi Ron: I think HP pioneered that method in one of their hand held calculators (PH35 or PH41)? -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html Original Message In your case, the car sits in an environment that matches their test setup well. In my case �\200� not so much. FWIW, mine drifts pretty badly. It's in an aftermarket stereo, and I don't remember when I bought it (I moved it from my previous car). I assume that all quartz clocks and watches these days use "inhibition conpensation". https://en.wikipedia.org/wiki/Quartz_clock#Inhibition_compensation ___ 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] Antique precision timing device without
Hi Morris: The GR 631 StroboTac includes a power line driven vibrating reed sticking into the reflector and so it's motion is stopped by the strobe. The patent has hand written comments regarding that idea. http://www.prc68.com/I/GRstrobotac.html#2331317 http://www.prc68.com/I/Images/Strobotac631-01b.jpg The idea here was to use the power line as a frequency reference. This would be fine since most of the applications for this strobe were related to line driven motors. -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html Original Message HI all, Thanks to all those who responded to my post and also for the great pics of other tuning forks. It's amazing that they were still being used for electronic purposes as recently as the 1960s. Actually now that I think about it I have seen little tuning forks used to check the function of modern police speed radars so they still have some use. Musicians don't use them any more - guitar players will know the little electronic tuning devices clipped to the neck of the instrument that displays the frequency or key of each string. Doctors still use 125 Hz forks to test vibration sense and higher frequency ones to test for conductive hearing loss. In answer to some of the questions posted: no there was no documentation with the unit. The most useful thing was the "12 volts in" label on the power socket so I knew where to start. The rest of it was necktop analysis. The fork is maintained by means of a central electromagnet and small leaf spring contacts on the tines - they also provide the 25 Hz power for the motor which runs at 12 volts. Of course they would reduce the Q of the fork a little and affect its resonance but I'm sure that was taken into account by the designer and the frequency & symmetry can be adjusted with the weights on the ends. Operating current is about 0.5A at 12 volts when running and 1A when the fork is not vibrating. There's a switch marked "Neon Lamp" that controls the AC supply to a pair of clips between the tines of the fork. They are about 3-4 inches apart and I have no idea what sort of long thin tubular lamp would fit between them. Just for fun I'm going to make a simple stroboscope with a 555 timer and some high intensity white LEDs I have lying around to see if I can use it on the fork. Cheers, Morris ___ 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] Vintage Frequency Measurement
Hi Bob: The BC-221 is usually referred to as either a Frequency Meter or a Heterodyne Frequency Meter. -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html Original Message Hi Ok, so how does that make a BC-221 a wave meter? Bob ___ 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] Vintage Frequency Measurement
Hi: Here's a GR 358 wavemeter from the 1920s. Someone noticed the GR logo after I made the web page that led to it's identification. Hence the generic page URL. http://www.prc68.com/I/Wavemeter.html Covers 14 to 220 Meters (21 to 1 MHz) in four bands selected by which inductor you connect to the variable capacitor. Resonance indicated by pilot light bulb. The peak indication depends on the system Q and so at higher frequencies is not very good. The microwave cavity wavemeters attached to the message from Wes have a much narrower peak and so are more accurate. Wes: Is this the patent for the IMPATT diode power amplifier? https://patents.google.com/patent/US3931587 -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html Original Message I have a General Radio Type CAG-60098-A Precision Wave Meter made for Navy Department - Bureau of Ships according to the nameplate. According to Wikipedia that would date it between 1940 (when bureau of ships was created) and 1966 (when abolished). It has an inductor in sort of a "hockey puck" labeled 16-50 kc that plugs into a socket on the front panel. Inside is a very nicely made variable capacitor with a vernier drive. It has been a while since I had it apart, but there is a diode in series with the meter and not much else as I recall. The meter scale is 0-200 (microamp?) and the capacitor scale is 0-75 with no other marking. I have no manual, but I assume there were other inductors for different frequency ranges with a calibration chart to interpret the 0-75 reading. It must have been made to test transmitters by tuning for peak reading on the meter and determining the frequency from the dial reading. a different Alan (KE7AXC) On Sun, Feb 12, 2017 at 5:47 PM, Alan Melia <alan.me...@btinternet.com> wrote: Hi Dan yes that is 5e-6 about all an unstabilised (temp) AT could hold for any period. I guess there were no WWV or MSF signals around then. When a good source was available off-air it was possible to do better than that. In service it was probably "dont waste time trying to better the minimum requirement. The transmitter you are looking for wont be that accurate or stable" In 1960s I saw several BC-221s in the racks at the Rugby LF and HF stations acting as standby frequency sources (VFO) for rapidly running up a transmitter on an unusual frequency (not a normal route) for which they did not have a crystal available. Alan G3NYK - Original Message - From: "Dan Rae" <dan...@verizon.net> To: "Discussion of precise time and frequency measurement" < time-nuts@febo.com> Sent: Sunday, February 12, 2017 11:11 PM Subject: Re: [time-nuts] Vintage Frequency Measurement To put BC-221 things in perspective, the 1 Mc/s reference crystal was adjusted, according to the manual, to within 5 c/s... Things have come a ways since! Dan ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/m ailman/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/m ailman/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] Vintage Frequency Measurement
Hi: When listening to a broadcast station using an analog receiver you just tune back and forth near the station frequency until you hear it, but that does not work for military radios where most of the time there is no transmission. Hence the need for frequency or wavemeters like the BC-221 and the LM series to set them on the assigned frequency. The calibration books for these meters were machine generated for each serial number unit. This was long before computers. The later FR-149B/USM-159A Frequency Meter uses a long 35mm film strip and an optical readout to get the 0.01% accuracy, and again is custom made for each serial number meter. But the need for them has almost gone away with the advent of synthesized radios. But there must still be some analog radios in use since the manual for mine has a date of March 2006. Note they are accurate signal generators (to set receivers) and have a hetrodyne capability to set transmitters. http://www.prc68.com/I/USM159.html When working at a microwave company we used cavity wavemeters where at resonance there was a suck out. -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html Original Message In a word,Wavemeters. Classic US onwas the BC221 with built in 100kHz crystal calibrator http://radionerds.com/index.php/BC-221 British was the "Class D"http://www.royalsignals.org.uk/photos/classDno1.htm For UHF and Microwave it was Lecher lines or cavity wavemeters. Robert G8RPI. From: Scott Stobbe <scott.j.sto...@gmail.com> To: Discussion of precise time and frequency measurement <time-nuts@febo.com> Sent: Sunday, 12 February 2017, 6:08 Subject: [time-nuts] Vintage Frequency Measurement I was inspired recently coming across a Lampkin 105 frequency meter, as to how frequency measurement was done before counters. Certainly zero-beating a dial calibrated oscillator, would be one approach. Is there a standout methodology or instrument predating counters? ___ 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] Manual for Ashtech Ranger Z-12?
Hi Björn & Peter: Thanks for the links to Z12 manuals. The Ranger Z12 is the same size as a field model Z12 but has different connectors, so different pin-outs than the more common versions of the Z12. I'd guess it runs on the same 10 to 32 VDC input. Some Photos at: http://www.prc68.com/I/AshtechZ12.shtml#Ranger -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html Original Message Here is also somewhere to look. ftp://ftp.ashtech.com/OEM_Sensor_ADU/Legacy%20products/Z12/ -- Björn Hi Brooke, There is a 16.5 Mbyte manual for the desktop model on: http://ashgps.com/mirror/master/Z12-Type%20Receivers/Manuals/z12.pdf ...don't know how different the portable "Ranger" model is. Peter On 8 February 2017 at 19:00, Brooke Clarke <bro...@pacific.net> wrote: Hi: I just got an Ashtech Ranger Z12 and am looking for a manual. It appears to be a field portable version of the rack mount Z12. Brooke Clarke ___ 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] Manual for Ashtech Ranger Z-12?
Hi: I just got an Ashtech Ranger Z12 and am looking for a manual. It appears to be a field portable version of the rack mount Z12. -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html ___ 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] Li-ion Battreries
Hi Mark: I agree. The Vietnam era PRC-25 radio had a solid metal battery box that was water tight and used a BA-4386 battery with Magnesium chemistry. http://www.prc68.com/I/PRC25.shtml#DCP The problem was that as a normal part of its operation the battery releases hydrogen gas. I know someone who has a scar on his head because when he opened the battery box the pressure shot it into his face. No chemical explosion, just gas pressure. The more modern radios that use the BA-5590 (BA is military speak for primary) Li-SO4 battery where the sulfur is compressed to make it a liquid have been known to explode if you try to charge them. This has resulted in a requirement for all battery boxes/spaces to allow for one cell to "vent" and not cause a problem. This is even more important with the current BB-2590 (secondary/rechargeable) battery made up of a couple dozen 18650 Li cells. http://www.prc68.com/I/BA5590.shtml#BB-2590Inside PS This "5590" family of batteries are all form-fit-function interchangeable and are made up of two "12 Volt" batteries in one 5.0 x 4.4 x 2.45" box. It's the standard battery in the military for non vehicle applications that need vehicle compatibility (ie either 12 or 24 volts). The radio or host device can wire its plug so the battery appears as either a 12 or 24 volt battery. While the long in the tooth BA-5590 can only supply a couple of amps (internal fuse) the newer BB-2590 can supply maybe 35 Amps for a short time, I think to start a motor. Rather that buying raw 18650 cells and connecting them getting a BB-2590 may be a better option. There are numerous military chargers that can charge them as well as hobby grade chargers that work with Li cells. There are some very low cost battery capacity testers on eBay: http://www.prc68.com/I/BatTst.shtml#Resistor - good for 18650 cell testing http://www.prc68.com/I/BatTst.shtml#EL - good for BB-2590 testing -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html The lesser of evils is still evil. Original Message They can be if you store them in something like an ammo box. If they "go off" in the sealed box the pressure builds, the reaction rate increases exponentially, and voila... shrapnel time. There's a video out there showing the results. Most people recommend storing them in nomex/kevlar "cell bags". I keep mine, bagged, in an unused/unplugged oven! If one goes off, hopefully the flames won't spread to the rest of the property and the hinged oven door allows pressure to escape. Hobby RC packs are one of the most dangerous type of rechargeable lithium cells out there... even from "reputable" sources and brands. A local hobby shop twice had brand new name brand packs sitting on the shelf go off. A friend of mine had the same thing happen carrying a just purchased pack home in his car. They aren't bombs, guys. Use sensible precautions and get on with it ___ 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] Temperature (environmental) sensors
Hi Tom: I've used the Onset data loggers and they are very inexpensive and work well. As a plus they are PIC based so hackable. Don't know about accuracy, resolution http://www.onsetcomp.com/products/data-loggers http://www.prc68.com/I/Hobo.html http://www.prc68.com/I/GPend.shtml The "Pendant" devices use an optical 2-way link to USB so there is no penetration in their water tight enclosure. -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html The lesser of evils is still evil. Original Message I have some high-end temperature and pressure instruments. But for casual use in my home and mobile timing lab I use Sparkfun Weather Stations. The old URL is: https://www.sparkfun.com/products/retired/10586 It's USB, talk-only, one reading a second, temperature, pressure, humidity -- about as simple as you can get. Perfect for data logging along with frequency standards, GPS, counters and such. But they don't make 'em anymore. My question is what similar well-engineered, talk-only, serial or USB, temperature-pressure-humidity sensors have you run across and could recommend? Not to be picky bit no cheapo 1C or 0.5C sensors; 0.1C or better is ok. I know it's "easy" to throw one together with an Arduino, but I'm looking for something pre-packaged, something that reliably works, out-of-the-box. I have backup plans but hope someone on the list knows some products they have used and would recommend. We could extend the discussion to voltage and power monitors too. Or some kind of universal sensor TAPR project. But for now, let's just keep it to simple air / environmental sensing. Thanks, /tvb ___ 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] Measuring sidereal/solar time? Re: A Leap Second is coming
Hi: Maybe this could be done with GPS or higher frequencies so the angular resolution would be better? -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html The lesser of evils is still evil. Original Message Brooke, The problem in radio ground observation can be resolution accuracy, but there's also a good transmission into far infrared wavelengths, which could require smaller dishes to get stellar images. The problem of far IR is the cost of right filters/sensor, which are a bit difficult to find. Radio objects, on the other hand, can be solved using an interferometer: LOFAR interferometers work at frequencies higher than 10MHz, frequencies totally transparent to the atmosphere and easily computable even by consumer PCs. There is some work done with common PCs using two RTL-SDR dongles and two satellite dishes. see http://www.sbrac.org/files/DTP_RX.pdf Best Regards, Ilia. On 12/30/16 17:18, Brooke Clarke wrote: Hi Anders: That's something I've thought about for decades using an optical system. A few years ago I looked at it again and found that astronomical "seeing" limits the accuracy. So the accuracy achieved by a spaceborne "Stellar compass" will be much better than a ground based observation. A radio based observation might work since the atmosphere would not be a factor. http://www.prc68.com/I/StellarTime.shtml ___ 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] Measuring sidereal/solar time? Re: A Leap Second is coming
Hi Anders: That's something I've thought about for decades using an optical system. A few years ago I looked at it again and found that astronomical "seeing" limits the accuracy. So the accuracy achieved by a spaceborne "Stellar compass" will be much better than a ground based observation. A radio based observation might work since the atmosphere would not be a factor. http://www.prc68.com/I/StellarTime.shtml -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html The lesser of evils is still evil. Original Message out of curiosity, are there any amateur/semi-pro experiments that can measure the length of the solar or sidereal day to sub-millisecond resolution? To reproduce data like this: https://upload.wikimedia.org/wikipedia/commons/5/5b/Deviation_of_day_length_from_SI_day.svg Something in the sky that goes "ping" every day - detected with a pointing accuracy of < 1ms/24h or <0.01 arc-seconds (!?). Or perhaps two satellite-dishes pointed at the sun and noise-correlation/interferometry?? Anders ___ 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] Problem with HP 83623A 20 GHz sweep generator stepping up/down 100 Hz when not wanted.
Hi David: Some time ago I built an automated mixer test system where I first attempted to use HP 8350B sweep generators as the sources for the LO and RF inputs, but this failed to work because at the narrow bandwidth settings on the HP 8566 spectrum analyzer there was way too much phase noise, so I switched to synthesized sweep generators made by HP and Wiltron, but I forget the model numbers. http://www.prc68.com/I/RASS_PP.html#Spur http://www.prc68.com/I/Images/RASS/Mixer.jpg The SA was operated at it's narrowest IF bnadwidth (100 Hz?) and I don't remember seeing any amplitude variations, whereas when the 8350 was used the amplitude jumped wildly. So I expect the problem is in the transverter. -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html The lesser of evils is still evil. Original Message I run a test over the weekend with a fellow radio ham. I transmitted 100 mW or so at 10368.115 MHz from an HP 83623A 10 MHz to 20 GHz sweep generator http://www.keysight.com/en/pd-101862%3Aepsg%3Apro-pn-83623A/synthesized-sweeper-10-mhz-to-20-ghz-high-power?cc=GB=eng into a small horn antenna inside my lab. He was able to receive me about 7 km away, although the signal was quite week - it was 20 dB above the noise in a 2.9 Hz bandwidth. What is odd, is that his transceiver + transverter combination indicates the signal generator is shifting frequency up/down 100 Hz. This is not slow drift, but a step change - see waterfall picture, where time is on the vertical axis, and frequency is on the horizontal. Unfortunately I don't know what the scale is on the vertical axis - I am trying to find out. The frequency on the x-axis is not the true frequency, but that shown on an 2 m amateur transceiver, so the true frequency is more than 10 GHz higher. The step size on this HP sweeper is 1 kHz, so the 100 Hz up/down shift is not due to a rotary encoder that might be just on the limit of two frequencies. Both the internal oscillator and a GPS locked frequency standard were used during this test. Going from internal to external reference caused a 450 Hz step in frequency, but did not change this up/down 100 Hz behavior. So the problem is certainly not the crystal in a 10 MHz reference oscillator, as two have been tried, one of which was locked to GPS. Does anyone have an idea what may cause this behavior? Does anyone have any ideas on the best way to investigate this, given the signal is at more than 10 GHz? What I do *not* have is any other signal generator capable of operation at 10 GHz. The only other sig gen I have is a 30 MHz Stanford Research DS345 function generator. I don't have a TI counter at the minute, but had an offer of $300 accepted on eBay for a 5370B a couple of days back, so should have a TI counter soon. (Yes, I have had an 5370B and SR620 in the past, but for various reasons no longer have them). The 5370B at $300 was a lot cheaper than an SR620. Other equipment I have include * 22 GHz spectrum analyzer * 30 MHz signal generator * 20 GHz VNA but no other signal generator capable of anywhere near 10 GHz. I do have a couple of double balanced mixers which have RF and IF inputs that will take 10 GHz, and an IF output that will go from DC to 4 GHz. Introducing a REALLY long delay might allow the steps to be seen, as the frequency at the LO and RF inputs of the mixers will be different. But that's not really practical, as I'd need an awfully long bit of coax. The 20 GHz vector network analyzer, which could be pressed into service as a poor (rich) mans microwave signal source, but I suspect the output of that is quite dirty, as the output is generated from a step recovery diode. I have not yet tested it on a spectrum analyzer, but the SA has quite a few spurious signals, so I'm never exactly confident of the SA. But one thing to possibly is * Set sweep generator to 10.368 GHz * Set sweep generator to 10.378 GHz, so there's a 10 MHz difference. * Mix the VNA + sweeper down to 10 MHz using a double balanced mixer * Compare the 10 MHz at the output of a mixer to that of a 10 MHz crystal. Steps of 100 Hz should then be seen I guess. Any better suggestions? Someone had kindly given me a key to change the step size of the signal generator from 1 kHz to 1 Hz. I've not applied that yet, as it is quite a complex procedure. But the fact the step size of this is 1 kHz, but it is shifting up/down 100 Hz, does not make sense. Especially given the unit is capable of 1 Hz resolution, but HP decided to charge extra for 1 Hz steps. Luckily this is just a software option. I did wonder if the signal generator was incapable of output the exact frequency needed, so it was stepped up/down periodically so it gave the right number of cycles over a long duration. But again, the fact it can step 1 Hz with just a software upgrade suggest that's not the case. The radio ham that noticed this step change in frequency is well used
Re: [time-nuts] Problem with HP 83623A 20 GHz sweep generator stepping up/down 100 Hz when not wanted.
Hi David: Do you have a comb generator? -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html The lesser of evils is still evil. Original Message I run a test over the weekend with a fellow radio ham. I transmitted 100 mW or so at 10368.115 MHz from an HP 83623A 10 MHz to 20 GHz sweep generator http://www.keysight.com/en/pd-101862%3Aepsg%3Apro-pn-83623A/synthesized-sweeper-10-mhz-to-20-ghz-high-power?cc=GB=eng into a small horn antenna inside my lab. He was able to receive me about 7 km away, although the signal was quite week - it was 20 dB above the noise in a 2.9 Hz bandwidth. What is odd, is that his transceiver + transverter combination indicates the signal generator is shifting frequency up/down 100 Hz. This is not slow drift, but a step change - see waterfall picture, where time is on the vertical axis, and frequency is on the horizontal. Unfortunately I don't know what the scale is on the vertical axis - I am trying to find out. The frequency on the x-axis is not the true frequency, but that shown on an 2 m amateur transceiver, so the true frequency is more than 10 GHz higher. The step size on this HP sweeper is 1 kHz, so the 100 Hz up/down shift is not due to a rotary encoder that might be just on the limit of two frequencies. Both the internal oscillator and a GPS locked frequency standard were used during this test. Going from internal to external reference caused a 450 Hz step in frequency, but did not change this up/down 100 Hz behavior. So the problem is certainly not the crystal in a 10 MHz reference oscillator, as two have been tried, one of which was locked to GPS. Does anyone have an idea what may cause this behavior? Does anyone have any ideas on the best way to investigate this, given the signal is at more than 10 GHz? What I do *not* have is any other signal generator capable of operation at 10 GHz. The only other sig gen I have is a 30 MHz Stanford Research DS345 function generator. I don't have a TI counter at the minute, but had an offer of $300 accepted on eBay for a 5370B a couple of days back, so should have a TI counter soon. (Yes, I have had an 5370B and SR620 in the past, but for various reasons no longer have them). The 5370B at $300 was a lot cheaper than an SR620. Other equipment I have include * 22 GHz spectrum analyzer * 30 MHz signal generator * 20 GHz VNA but no other signal generator capable of anywhere near 10 GHz. I do have a couple of double balanced mixers which have RF and IF inputs that will take 10 GHz, and an IF output that will go from DC to 4 GHz. Introducing a REALLY long delay might allow the steps to be seen, as the frequency at the LO and RF inputs of the mixers will be different. But that's not really practical, as I'd need an awfully long bit of coax. The 20 GHz vector network analyzer, which could be pressed into service as a poor (rich) mans microwave signal source, but I suspect the output of that is quite dirty, as the output is generated from a step recovery diode. I have not yet tested it on a spectrum analyzer, but the SA has quite a few spurious signals, so I'm never exactly confident of the SA. But one thing to possibly is * Set sweep generator to 10.368 GHz * Set sweep generator to 10.378 GHz, so there's a 10 MHz difference. * Mix the VNA + sweeper down to 10 MHz using a double balanced mixer * Compare the 10 MHz at the output of a mixer to that of a 10 MHz crystal. Steps of 100 Hz should then be seen I guess. Any better suggestions? Someone had kindly given me a key to change the step size of the signal generator from 1 kHz to 1 Hz. I've not applied that yet, as it is quite a complex procedure. But the fact the step size of this is 1 kHz, but it is shifting up/down 100 Hz, does not make sense. Especially given the unit is capable of 1 Hz resolution, but HP decided to charge extra for 1 Hz steps. Luckily this is just a software option. I did wonder if the signal generator was incapable of output the exact frequency needed, so it was stepped up/down periodically so it gave the right number of cycles over a long duration. But again, the fact it can step 1 Hz with just a software upgrade suggest that's not the case. The radio ham that noticed this step change in frequency is well used to listening on 10 GHz, and hearing beacons. So I think its reasonable to assume that the problem is not his end, but my end. Any thoughts, which do NOT include purchasing a second expensive 20 GHz signal generator. They are around $10,000 each, so a bit out of my price range. Dave ___ 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
Re: [time-nuts] OT: ExpressPCB (cross-post from volts-nuts)
Hi John: Yes. It is not at all economical to have ExpressPCB make boards the final size in production. BUT . . . if you have them make panels and cut them apart yourself it's very reasonable. I've used many methods for cutting the boards apart but have settled on a 12" metal shear that cuts them as easy as cutting butter. http://www.prc68.com/I/12InShear.shtml There is a limit on the number of holes so you can not use holes as a way to snapping panels into individual boards. Note the largest boards they make are 12 x 14". They are in Portland, USA. I think they are charging 34 cents/sqin (5-day) plus other charges on a per order and per board basis. For example: https://www.expresspcb.com/production-service/ -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html The lesser of evils is still evil. Original Message That points out a key difference in the PCB house pricing models: ExpressPCB and the Advanced Circuits $33 prototype are flat fee up to a size limit (for Advanced Circuits 4 x 6 inches) while others go by the square inch -- OSH Park is $5/in2 for three copies of two layer, and $10/in2 for three of four layer. So for small boards, OSH Park is great but for larger boards, the price difference reduces (a 4 x 6 board ends up being just about the same price as Advanced Circuits). And if you can stand the slower turnaround, the Chinese board houses can't be beat for any size. John On 12/9/2016 3:18 PM, Bob Stewart wrote: I built my first set of boards with ExpressPCB, but they get expensive quickly if you want to make something that's not in their special form factor. I use KICAD and OshPark.com to make my boards (there are other board makers). I just ordered some boards that are .7" x .63" that cost $8.40 for 12. You buy in multiples of 3, so that was actually $2.10 for a set of 3 times 4 sets. Using surface mount, I was able to put an SOIC-14, an SOIC-16, an SOT23-5, three 0805 caps, a 3 pin header, and a 5 pad connector on the board. Something like that would be wastefully expensive on ExpressPCB. Bob From: BIll Ezell <w...@quackers.net> To: time-nuts@febo.com Sent: Friday, December 9, 2016 1:58 PM Subject: [time-nuts] OT: ExpressPCB (cross-post from volts-nuts) Sorry if I'm behind the times, just did a new project that required a pcb, and ExpressPCB is my go-to vendor for one-off boards. I just noticed they now provide the low-cost boards (fixed size, 3x5, quantity 3) that I've always ordered with silk screen and solder mask for $71. I got my latest boards that way and they're beautiful. No relationship to them, just a happy customer. You can still get the barebones boards for $51. The hack I used to use was to put the component id and such on the top copper layer as tiny text, but that was a bit of a pain for layout. (Oops, can't put that label there, it's copper and there's a trace there also) Really nice to be able to get real boards, even if it does end up being ~$23/board. ___ 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] OT: ExpressPCB (cross-post from volts-nuts)
Hi Bill: It's their Mini Board Pro service and you get 3 each 2-layer boards each 3.8 x 2.5" with solder mask (great for SMT) and silk screen top side labels for $61. https://www.expresspcb.com/miniboard-pro/ If you get this service some caution is needed regarding the solder mask since it's possible to have the mask where you were expecting to see metal. Also note they have free schematic software that can be used to check the nodes on the board layout. -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html The lesser of evils is still evil. Original Message Sorry if I'm behind the times, just did a new project that required a pcb, and ExpressPCB is my go-to vendor for one-off boards. I just noticed they now provide the low-cost boards (fixed size, 3x5, quantity 3) that I've always ordered with silk screen and solder mask for $71. I got my latest boards that way and they're beautiful. No relationship to them, just a happy customer. You can still get the barebones boards for $51. The hack I used to use was to put the component id and such on the top copper layer as tiny text, but that was a bit of a pain for layout. (Oops, can't put that label there, it's copper and there's a trace there also) Really nice to be able to get real boards, even if it does end up being ~$23/board. ___ 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] Space-borne frequency comb metrology
Hi: https://www.osapublishing.org/optica/abstract.cfm?uri=optica-3-12-1381 Free on line pdf at: https://www.osapublishing.org/optica/viewmedia.cfm?uri=optica-3-12-1381=0 "Precision time references in space are of major importance to satellite-based fundamental science, global satellite navigation, earth observation, and satellite formation flying. Here we report on the operation of a compact, rugged, and automated optical frequency comb setup on a sounding rocket in space under microgravity. The experiment compared two clocks, one based on the optical D2transition in Rb, and another on hyperfine splitting in Cs. This represents the first frequency comb based optical clock operation in space, which is an important milestone for future satellite-based precision metrology. Based on the approach demonstrated here, future space-based precision metrology can be improved by orders of magnitude when referencing to state-of-the-art optical clock transitions." -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html The lesser of evils is still evil. ___ 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] Vintage Quartz Crystal Manufacturing
Hi Adrisn: The BC-611 Walkie-Talkie is a crystal controlled 2-way radio where there are a set of 4 components that need to be changed whenever a different frequency is needed. This needs to be done in a workshop and not it the field. http://www.prc68.com/I/BC611.shtml Those 4 components are the Rx crystal, Tx crystal, Tank coil and antenna coil. All of these were marked with the radio frequency rather than typical parameters for a component. So just because a component is marked with a frequency you can not be sure it's a crystal, coil or whatever. The URC-4 survival/rescue radio uses cylindrical crystals CR-24/U package): http://www.prc68.com/I/URC4.html#Components -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html The lesser of evils is still evil. Original Message The markings are actually 3720 k/cs, 3760 k/cs and 3780 k/cs. And I think it's probably for the wireless No 7 shown in http://www.wftw.nl/wsets.html. But you could be right - they may not be crystals. As for ebay .. yes, buyer beware. Though in this case I know the seller personally and while he might be mistaken, he won't be intentionally misleading. On Sat, Nov 26, 2016 at 3:15 PM, Bob Camp <kb...@n1k.org> wrote: Hi Welcome to eBay ….. I don’t believe those are crystals at all. If you take a look at the markings on the parts they are labeled “80 K cps”. In other words they are 80 KHz not 80M devices. Looking at the gap, if there is a crystal in there it’s not obvious that it’s big enough for 80 KHz. My guess is that they are tank tuning caps for an mechanical MOPA style transmitter. The size and construction are about right for that sort of thing. Swap one in and the transmit frequency changes. Number 7 for 80 KHz. Number 8 for 85 KHz. Number 7 for 75 KHz. Just a guess … Bob On Nov 26, 2016, at 7:40 AM, Adrian Godwin <artgod...@gmail.com> wrote: I bought some old crystals on ebay : http://www.ebay.co.uk/itm/15114483 Is anyone familiar with this style ? I don't think the quartz is visible in the glass section : I imagine that's just an insulator. I think the quartz is under a brass disc, with a sping to hold the disc down visible through the glass. Does anyone know what the reference marked on them "w'less sets No 7" refers to ? On Mon, Sep 26, 2016 at 6:50 AM, Mark Sims <hol...@hotmail.com> wrote: Can you say "Mr Rogers' Neighborhood?" I knew you could... He (along with creepy Mr McFeelie) always ran segments on how some item was made. Geared towards pre-schoolers, but always worth watching. - Compare the Science channel's new "How Do They Do It" to the older "How It's Made" shows. ___ 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. ___ 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] Nutty time-nuttery with WWVB
Hi Pete: It's been 4 years since WWVB added phase modulation that's supposed to fix the East coast problem. Have you tried using a clock that makes use of it? For example the La Crosse Model # 404-1235UA-SS from Home Depot. I haven't got one yet since they are about $60 and my old style WWVB clocks work fine, but it would be a lot easier to get one as opposed to building something. -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html The lesser of evils is still evil. Original Message I have a few of those "atomic" clocks that receive WWVB to set the time. However since I live on the east coast they may only pick up the signal once or twice per year. Could I implement my own personal WWVB transmitter that would be powerful enough to be picked up by the clocks in my house? The signal at 60 KHz might be able to be produced directly by some sound cards. With that and a ferrite rod antenna I might get reliable time elsewhere in my house outside of my lab. Has anyone tried this? 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. ___ 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] Thinking outside the box a super reference
Hi Bert: Have you looked into the Stanford Research PRS-10? It a current production Rb standard with internal provision to sync to 1 PPS. http://prc68.com/I/PRS10.shtml You can choose to run it like a GPSDO but it needs an external 1 PPS for that (there is no GPS receiver in the PRS-10). Or, you can time stamp an external 1 PPS. The company was founded by a physicist and they hire mostly physicists rather than engineers. I like their stuff. The crystal oscillator in the PRS-10 is the SC-10, also made by SR and comes in many flavors that among other things trade off aging for stability. I assume you could order a custom PRS-10 with the desired crystal oscillator specs. Before spending a lot of money you might want to experiment with the PRS-10 and the best currently available GNS timing receiver. I experimented with both hardware and software sawtooth correction and they both have pluses and minuses. I seem to remember that CNS Systems had a sawtooth corrected GPS timing receiver that ran TAC32 software, but haven't kept up on it. -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html The lesser of evils is still evil. Original Message Over the past there has been talk about building from scratch high performance references. I think consensus was that it is out of reach. In the mean time Corby is reworking an active maser which takes a lot of know how. But let us look at his work on the super HP5065. It is able to outperform a passive maser in the below 100 second range! Long term a proper GPSDO should be possible to step in. We are working on it including pressure and temperature control. To make full use of it you also need to have the capability to monitor, record and analyze on a continuous basis preferably with out tying up expensive equipment. We have the pieces in place and looking forward of combining all the pieces and compare with Corby’s active Maser. We are back to the GPSDO after being distracted by Tbolt performance. A third party is working combining the GPSDO data stream with the data from the unit that generates frequency, pressure and temperature data along with time to a USB stick, while also be able to monitor with a PC. I know it is considered by some heresy but our lack of a Maser and in Juerg ’s case no access to one, we try to overcome it with a GPSDO tailored for Rb and Cs and control our Cs’s C field . There was a time that I did have a HP5065A but got rid of it when I got some Cs’s. My best counter was A HP5345 and even with a Tracor 527 1 second performance was not an issue. That changed when Corby introduced me to time nuts and frankly it was the first time I learned about ADEV. But the HP5065A was gone. Now I have a cell that Corby has plotted and time permitting may become a project. Let me get to the real issue. There are not enough HP5065A’s out there and not affordable for all time nuts. Most are being kept and are not for sale. But if a combined effort by many time nuts it MAY be possible to recreate the guts of the HP5065A. The key word is MAY. 200 time nuts be willing to invest $ 5000 each may get us there. The market does not justify such an effort but time nuts keep bringing up discussions. All the other ideas kicked around in the past will cost more. There are some among us that know what it cost and who can make the key elements like lamps, cells, filters etc. Just a thought outside the box and hopefully may turn in to a limited constructive dialog. We will continue on our path, which include FRK/M100, HP5065 and Cs. We would not be capable to contribute technically on the physics package but I would be willing to contribute financially and with monitoring equipment even if I would not be around when finished. Bert Kehren ___ 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] 1PPS to 32.768 khz
Hi Lee: 32768 can easily be divided down to drive the clock. So why not bypass the 32768 and drive the clock directly from the 1 PPS you now have. http://www.prc68.com/I/QuartzClk.shtml -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html The lesser of evils is still evil. Original Message First let me say this is first time I have posted to the group so go easy on me. :) Secondly I want everyone to know that you guys make me feel so NORMAL for wanting to use and understand accurate timing devices. I thought there was something seriously wrong with me now I know there are others affected with the same disease. hehe Now my questions. 1. Does anyone know of a device that will take a 1PPS GPS timing signal and generate a 32.768 kHz sine wave output ? I have big digital clock that uses an 8 bit micro processor and an external 32.768 crystal. Obviously the external crystal is awful for accuracy. I have searched every where using as many search terms as I can think of and can’t believe there is not a device that performs this function. I have found a couple of Epson RTC chips that might come close that 1pps but I don’t think that corrects the 32khz just the clock time. 2. 10 Mhz Freq Standard I am not in the same league as the majority of the list members and just starting to dabble in GPSDO stuff. I have tried to find a thunderbolt as a starting device but it appears those are either dried up or people want too much money. I wanted to get the opinion of anyone who has tried the Leo Bodnar GPSDO ? For the money it appears to offer a beginner a lot of features. Thanks and reading the daily digest of what you guys are working on. I have a feeling if I am not careful you guys could cost me a lot of money. hehe Lee ___ 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] Rare HP clock
Hi: Let me second Chuck's comment on the noise. You can NOT have this inside any living space. I saw this based on running an HP 117 for some time in the garage but also have one of the 115BR units. http://www.prc68.com/I/Images/Rack2bb.jpg http://www.prc68.com/I/TF_rack.html PS there are internal momentary switches on the117 multipliers that need to be tweaked to start them so if it totally stops it takes some effort to get it going again. -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html The lesser of evils is still evil. Original Message I have one of those, only in light gray. It works quite nicely, though it is obscenely loud! It has a divider network that takes 100KHz from a companion reference unit, and divides it down to 1KHz, that it uses to drive a stepper motor used as a synchronous motor. The motor drives the mechanical counter mechanism. Because the motor is being driven with a single phase 1KHz signal, you have to give its shaft a spin to start it. There is a little crank driven synchro generator that is used to insert a phase difference into the 100KHz reference signal that serves to shift the edge of the 1PPS output. It is built into a cast aluminum chassis, that is sealed with O-rings, and even has a humidity monitor to show the condition of the air in the unit. The biggest issues I can see with it are the strong 1KHz audio note, the condition of the ball bearings that support the motor shaft, the little herd of wet tantalum capacitors in its circuitry, and the internal nicad pack that keeps it live during short power failures.. The mechanical counter probably needs some cleaning and lubrication at this point. -Chuck Harris Dave M wrote: It's Ebay item 351861979923 Dave M KA2WEU--- via time-nuts wrote: I can not find the item on EBAY , Ulrich In a message dated 10/3/2016 11:51:24 A.M. Eastern Daylight Time, jn6...@gmail.com writes: According to my -hp- catalogs it was available only in rack-mount form, not in a cabinet. That suggests it was being marketed to a specific small group so it may indeed have been manufactured in small quantities. Jeremy ___ 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] HP-105B Battery Replacement?
Hi Attila: The difference in chemistry I got from "Handbook of Batteries" 3rd ed, 2001. Your comments about modern chargers are correct, but this thread is about the HP 105 which uses what we both might call an old fashioned charging circuit. -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html The lesser of evils is still evil. Original Message On Fri, 16 Sep 2016 11:37:23 -0700 Brooke Clarke <bro...@pacific.net> wrote: The chemistries are very different. Ni-Cad is endothermic whereas Ni-MH is Exothermic. This is why chargers for Ni-MH have a mandatory temperature sensor. This is one of the reasons I say Ni- Cad cells batteries are easy to charge. Both NiCd and NiMH behave the same way chemically. Both reactions are exotherm when the batteries are full, i.e. the electrical energy you put into them cannot be "absorbed" chemically and thus is dissipated through heat. (I'm not sure whether it's correct to talk about exotherm/endotherm in this kind of setting, i'd appreciate if someone with chemistry knowledge would correct me) The reason why NiMH charger "need" a temeperature sensor is, because the classical fast-charger for NiCd uses the negative dV/dt slope when the battery gets full to detect end of charging, but the peak is much less pronounced with NiMH than with NiCd (factor 2-5 IIRC). Hence people were adviced to use only NiCd fast-chargers which had a temperature sensor. Slow chargers (i.e. 0.1C chargers) do not have this problem, though you shouldn't leave the battery on for days (NiMH is a quite bit more sensitive when it comes to overcharging). "Modern" fast-chargers for NiCd/NiMH chemistries have adjusted their dV/dt trip point to reliably trigger with NiMH. Additionally all better chips (probably all chips, today?) use pulse charging where the battery is measured during a short no-charge period to more accurately measure the batteries condition. NiMH is a good replacement for NiCd if you can live with the drawbacks. Namely: * slightly trickier charging (but that's the problem of the charger) * more sensitive to over/under charging * higher self-discharge On the positive side, you get a greatly reduced memory effect (to the point where a lot of people say it doesn't exist). Attila Kinali ___ 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-105B Battery Replacement?
Hi David: The chemistries are very different. Ni-Cad is endothermic whereas Ni-MH is Exothermic. This is why chargers for Ni-MH have a mandatory temperature sensor. This is one of the reasons I say Ni-Cad cells batteries are easy to charge. -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html The lesser of evils is still evil. Original Message NiMH batteries are close the same voltage and charge the same as NiCd and are more available and not toxic when disposing of them. They should be a good replacement. Lithiums are very different in voltage and charging. David N1HAC On 9/14/16 10:19 PM, Jeremy Nichols wrote: Thanks, Brooke, I'll price new Ni-Cads. I wasn't thinking of lead-acid (gel cells) but rather lithium rechargeable, providing I can find a type that won't catch fire and will work with the 105B'scircuits. Jeremy On Wednesday, September 14, 2016, Brooke Clarke <bro...@pacific.net> wrote: Hi Alex: Yes, I'm recommending Ni-Cad but NOT any acid type. -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html The lesser of evils is still evil. Original Message Hi Brooke, sorry I have to disappoint you; Ni-Cd batteries do not use any acid, they have K-OH kalium hidrioxid [potassium hydroxide for anglophone ] as electrolyte and they are normally very air-tide, and widely used in radios. 73 KJ6UHN Alex On 9/14/2016 4:45 PM, Brooke Clarke wrote: Hi Jeremy: It's a very bad idea to put any battery with acid in an enclosure that has electronics since if it vents the acid will etch the PCBs. Guess how I learned this. I got a great price on a Gibbs Frequency Standard because the oven no longer worked. http://prc68.com/I/office_equip.html Modern Ni-Cad batteries have much more capacity than older ones and no longer have a memory effect. They are also very easy to charge, so why not just replace the old cells? ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/m ailman/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/m ailman/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] HP-105B Battery Replacement?
Hi Jeremy: I'm currently having fun playing with various rechargeable battery related stuff which includes Li-Ion cells. http://www.prc68.com/I/BatTst.shtml#Resistor The cells come in three configurations: 1. the raw flat top cell with optional tabs to allow easy soldering into a pack, 2. cell plus positive button cap which includes a Positive Temperature Coefficient (PTC) fuse and an over pressure vent, 3. fully protected, like 2, plus circuit that turns off the battery if charging and over voltage or loaded and under voltage. On these you can feel a wire/ribbon running from positive to negative under the shrink wrap and they are slightly longer. These configurations are independent of the flavor of Li chemistry. To go with any of the above you need a charger specific to the particular Li chemistry (the charging voltage is not the same) and if a pack you also need a either cells like 3 above or a protection circuit for the pack. For optimum performance in addition a tap between each virtual cell (made of of parallel cells) so that the charge can be balanced and a charger that can do that. This is not easy, witness the current recall of the Galaxy Note 7s phones. I would just use modern Ni-Cad cells mainly because of the ease of charging and maintaining them and use the existing charging circuitry. Li chemistry has advantages for portable equipment, but not so much for rack mounted equipment. -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html The lesser of evils is still evil. Original Message Thanks, Brooke, I'll price new Ni-Cads. I wasn't thinking of lead-acid (gel cells) but rather lithium rechargeable, providing I can find a type that won't catch fire and will work with the 105B'scircuits. Jeremy On Wednesday, September 14, 2016, Brooke Clarke <bro...@pacific.net> wrote: Hi Alex: Yes, I'm recommending Ni-Cad but NOT any acid type. -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html The lesser of evils is still evil. Original Message Hi Brooke, sorry I have to disappoint you; Ni-Cd batteries do not use any acid, they have K-OH kalium hidrioxid [potassium hydroxide for anglophone ] as electrolyte and they are normally very air-tide, and widely used in radios. 73 KJ6UHN Alex On 9/14/2016 4:45 PM, Brooke Clarke wrote: Hi Jeremy: It's a very bad idea to put any battery with acid in an enclosure that has electronics since if it vents the acid will etch the PCBs. Guess how I learned this. I got a great price on a Gibbs Frequency Standard because the oven no longer worked. http://prc68.com/I/office_equip.html Modern Ni-Cad batteries have much more capacity than older ones and no longer have a memory effect. They are also very easy to charge, so why not just replace the old cells? ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/m ailman/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/m ailman/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] HP-105B Battery Replacement?
Hi Alex: Yes, I'm recommending Ni-Cad but NOT any acid type. -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html The lesser of evils is still evil. Original Message Hi Brooke, sorry I have to disappoint you; Ni-Cd batteries do not use any acid, they have K-OH kalium hidrioxid [potassium hydroxide for anglophone ] as electrolyte and they are normally very air-tide, and widely used in radios. 73 KJ6UHN Alex On 9/14/2016 4:45 PM, Brooke Clarke wrote: Hi Jeremy: It's a very bad idea to put any battery with acid in an enclosure that has electronics since if it vents the acid will etch the PCBs. Guess how I learned this. I got a great price on a Gibbs Frequency Standard because the oven no longer worked. http://prc68.com/I/office_equip.html Modern Ni-Cad batteries have much more capacity than older ones and no longer have a memory effect. They are also very easy to charge, so why not just replace the old cells? ___ 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] HP-105B Battery Replacement?
Hi Jeremy: It's a very bad idea to put any battery with acid in an enclosure that has electronics since if it vents the acid will etch the PCBs. Guess how I learned this. I got a great price on a Gibbs Frequency Standard because the oven no longer worked. http://prc68.com/I/office_equip.html Modern Ni-Cad batteries have much more capacity than older ones and no longer have a memory effect. They are also very easy to charge, so why not just replace the old cells? -- Have Fun, Brooke Clarke, N6GCE http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html The lesser of evils is still evil. Original Message I recently acquired a nice HP-105B, serial prefix 1240A, and like Perry Sandeen (posted here 10 May 2016) was pleasantly surprised to find a 10811-type oscillator inside in place of the old blue oven. Well, the oscillator isn't actually labelled "10811" but has a label "Serial No. 3010A62646 / Hewlett Packard / Made in U.S.A. / R11 147K." So, this is essentially the same oscillator as Perry found in his 105B. The oscillator works well although the meter reading for the 5 MHz output is low, about 30 instead of the expected 80 (per the 105B manual for the 1240A series). The measured output is also low, about 1 Volt where 1.5 Volt is the expected minimum. Might this be due to the change from the old 105 crystal oven to the 10811? What is the received wisdom on replacement of the previously-removed factory Ni-Cad pack? There are many small 12 Volt batteries available, two of which would easily fit into the space available and some of which might not even catch fire! Other options are an external battery+charger or even a UPS on the AC line. Opinions? Jeremy / N6WFO ___ 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] Hobbyist grade or homebrew temperature testing chamber?
Hi Rick: I've used two types. 1. Most of the replies have been for controlled air temperature devices. These are by far the most common but also they take a long time to change temperature. 2. Hot/Cold plates are much faster since the DUT is in close contact with the plate. We used these with a PID controller and liquid Nitrogen gas. Just toss a towel over the DUT and you have very fast cycle times. I built a DIY version for heat only using a couple of flexible heater strips glued to aluminum blocks, a PID controller and a 10k thermistor embedded in one of the blocks. The Steinhart-Hart thermistor equation is of the third order with respect to R but it is linear with respect to the coefficients making it easy to fit. http://www.prc68.com/I/Sensors.shtml#Temperature The unit is hiding from me, maybe it's photo shy. -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html The lesser of evils is still evil. Original Message As we all know, step #1 in making a clock is NOT to build a thermometer :-) I thought I would check the brain trust here to see if anyone has seen a hobbyist grade temperature testing chamber or kit or homebrew design. I have some crystals, oscillators, and other electronics I would like to characterize over temperature. I know this reflector has discussed homebrew stabilization ovens; however, they have tended to have very long time constants (which makes sense for that application). I need to be able to change temperature in a reasonable amount of time, and I don't need extreme stability. Looking for any ideas, maybe in the "maker" spirit. I think the size I need would be perhaps 1/2 the size of a shoebox. BTW, in case someone has a chamber to sell, let me know... 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. ___ 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] GPS for Nixie Clock
Hi Mark: Reaction time for a one off event like a starting pistol is different than to a repetitive event. For example when hearing the seconds ticks the 1 PPS edge can be set to within milliseconds on a clock that has that capability. http://prc68.com/I/PRC68COM.shtml#07092006 (see photo 11 Aug 2006 for 4 hex character fractional seconds). -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html The lesser of evils is still evil. Original Message Last month there was a discussion here about using a GPS to drive a hyper-accurate nixie tube clock with a lot of the discussion revolving around the effects of human perception and reaction times. Here is blog post that discusses some of the gotchas software and hardware can impose. There are some links near the end to some papers covering reaction times. http://goughlui.com/2016/08/22/opinion-can-you-beat-usain-bolt-not-so-fast/ ___ 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] DIY VNA design
Hi Dave:
I worked on the HP/Agilent 4380S test system software. The 4380A test set has 8 ports and 3 receivers (R, A & B) as
well as a built-in Short - Open - Load to speed up the calibration. Uses bridges.
http://www.prc68.com/I/4395A.shtml#4380
Used for measuring both ends of CAT5 cable and Firewire where each wire gets a test port. S-parameters transformed into
Z-parameters to balanced parameters. Note this system can test BALUNS where one port is coax and the other balanced
terminals.
--
Have Fun,
Brooke Clarke
http://www.PRC68.com
http://www.end2partygovernment.com/2012Issues.html
The lesser of evils is still evil.
Original Message
On 8/21/2016 3:59 PM, Dr. David Kirkby (Kirkby Microwave Ltd) wrote:
That said, I don't know why the author is using directional couplers. A
bridge is much wider bandwidth. It is more lossy though.
In general, a resistive bridge will always require a
transformer/180 degree hybrid/differential amplifier
to make it work. If you are going to go to the trouble
of making a broadband transformer or hybrid, you might
as well just build a traditional directional coupler,
because it is no more difficult. All the resistive
bridges I have seen are followed by broadband differential
amplifiers. The resistive bridge itself has a minimum of
something like 15 to 20 dB loss, and the differential
amplifier has a minimum NF of 7 dB or so. This results
in a great loss of sensitivity, but you can always get
the sensitivity back by using a narrow IF bandwidth and/or
lots of averaging, or (rarely) a high drive level from
the source.
Having said that, one of the putative advantages of a resistive
bridge is accuracy. However, with today's calibration techniques,
this is no longer all that important, so a traditional coupler
might be more practical than it used to be. I remember attending
the retirement party of Agilent's last great designer of couplers
(pre-calibration) and let me tell you, this guy was a total guru.
He was one of greatest practitioners in this area of all time.
He freely admitted that he was now obsolete due to calibration.
Any old coupler is good enough.
Anyway, it is an interesting project, but personally if I were going to
go to the effort of building a 2-port VNA, I would build one with 4
receivers.
Dave
___
We used to have a lot of arguments at Agilent about how many
receivers were needed. The most I ever heard advocated was 5,
and the least was 1 or 2. I had to intervene in some of these
arguments to bring up what I call the "back door reference"
fallacy. If you were making a "scalar" network analyzer that
only dealt with amplitude, you could make various arguments
about why you don't need so many receivers. In principle,
1 receiver could work. (The achilles heel of this idea
turns out to be imperfect repeatability of switches, and
very long settling times and thermal tails in switches.
None of these calibrate out).
In any event, as soon as you start talking about vector
network analyzers, you are measuring phase. Unlike amplitude,
phase is always a relative measurement. That is why you
need a reference ("R" channel). You compute A/R. This
requires a minimum of 2 receivers, an "A" and an "R".
Concurrently, not consecutively. Architectures that skimp
on receiver count, or ostensibly omit the reference channel,
are really a cheat. There will be some back channel between
the instrument clock and the sampling clock in the ADC that
in essence acts as a reference channel. If there is any
warm up drift in the phase of this channel, you will get
non-correctable errors if you try to multiplex a single
receiver. It is also another source of crosstalk on the
PC board.
Another problem with skimping on receivers is that you
can't do full 2 port calibration, I used to
have people show me "proof of concept" why they don't need
full 2 port calibration. They would compare a test of
some simplified architecture to some top of the line VNA
and show that the measurements were the "same". Just like
the graphs you see comparing low cost VNA's to Agilent
VNA's (it always seems to be Agilent, not one of the other
name brands). It would often turn out that these "benchmarks"
were not good tests of the analyzer. Changing to more
challenging tests would reveal the true superior design.
For example, if you calibrate with a short, open, and load,
and then measure the short, it always looks perfect. But
if you add a short length of transmission line in front of
it, the simplified architecture may not work so well any
more. This is called a "remote short" test.
Rick
___
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] Working with SMT parts.
Hi Steve: If you are going to be soldering then you NEED stereo vision, a monitor screen will not work at all. You need depth perception as well as magnification. Think of the microscope as part of a feedback loop that includes your eyes and muscles. With a stereo microscope you can make much smaller hand movements which are required when working with small pitch ICs. -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html The lesser of evils is still evil. Original Message Can anyone compare the stereo microscope to a camera/monitor for use with SMT? I have a cheap stereo microscope that I would like to replace with either a much better stereo microscope or a camera/monitor. Is there a marked advantage(s) of one versus the other? I have no "floaters" to contend with. Steve, K8JQ On 8/11/2016 4:06 PM, Chuck Harris wrote: Lots of good suggestions have already been made, but for me, a boom style stereo microscope, with a distance between the objective, and the focal point of at least 3 inches works fairly well... One other thing that may force your decision, if you are older, your eyes will likely have lots of "floaters", which are debris that floats around in your eyeballs. This debris floats in and out of the center of your field of view, and looks like a bunch of translucent worms, or shadows. Your brain, the magnificent organ that it is, tries to compensate for your eye's degradation, and as long as your eyes can move about in your field of view, it effectively removes the floaters from the scenes you are viewing. However, if you use a stereo microscope, your eye position is fixed by the very limited amounts of off axis motion that will allow a through optical channel. This lack of off axis motion will emphasize your floaters in a great way, and you will see *every* *single* *one*, clearly, as if it were something you really wanted to view. Some times, the floaters will cover the exact thing you need to see clearly, and you will have to move it off axis by moving it on the microscope stage. The only answer to this problem, is to either have perfect eyes, or to use a microscope where you are looking at a screen, rather than through a pair of oculars. This way, your eyes can dart around, and inspect what they need to see clearly, and the floaters will be ignored by your brain. As far as I know, there is only one optical microscope built this way, and it is the very expensive Mantis. Because of the great expense of flat screen optical microscopes, most modern SMD viewing equipment is going to the trivially cheap method of using a CCD/CMOS color video camera and an LCD screen. You can do a lot with a cheap USB camera mounted to a boom, a fiber optic light source, or a ring light, and a laptop computer to display the image. -Chuck Harris Bob Albert via time-nuts wrote: What are the important parameters regarding purchase of a stereo microscope? I see some on ebay for around $50; are those good? Bob ___ 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] Working with SMT parts.
Hi Chris: ExpressPCB has very easy to use free software for schematic capture (later used to check the board wiring) and software for board layout including making custom components if their library of stock components does not have what you need. The output file format is proprietary, which makes it interesting that Far Circuits can read it. I just have not wanted to go through learning curve for Gerber files and all the associated stuff (maybe drilling, silk screen, solder mask) which is very easy to do with ExpressPCB. When you start buying many circuits per board and a number of boards from the the price gets a lot lower. When I try Far Circuits I expect it to drop by a small integer (1/2, 1/3 . . 1/4?)..\ -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html The lesser of evils is still evil. Original Message This seems totally backwards. Typically a Gerber file is something you make yourself on your computer then send it in for a prototype. Seems odd to buy them. I checked ExpressPCB prices and they are very high. I can get PCBs made quickly in the US for $3 per square inch, shipping included with $9 minimum order. And you don't buy the Gerbers. I notice ExpressPCB offers free software. But it is totally non-standard and you can't use it for anything other then for their service. Most people needing free PCB software use Eagle, some use Kicad or some others. But Eagle seems to be kind of a universal standard. On Thu, Aug 11, 2016 at 8:55 AM, Didier Juges <shali...@gmail.com> wrote: I concur. I have been using ExpressPCB extensively over the last 2 years with great satisfaction now that it is possible to get Gerber files from them. I typically use the mini board pro service (3 bare boards, 2 sided with solder mask and silk screen) for prototypes and then buy the Gerbers ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Working with SMT parts.
Hi Chuck: The Mantis is very expensive and the arm in the EEVblog review is not as stable as my arm. https://www.youtube.com/watch?v=a3o0EWHEH08 about US$ 3300 retail, maybe $2000 eBay. In the review he is confused about 3D vs. perspective. The working distance does not look as long as the B http://www.prc68.com/I/SMT.shtml#Mag -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html The lesser of evils is still evil. Original Message Lots of good suggestions have already been made, but for me, a boom style stereo microscope, with a distance between the objective, and the focal point of at least 3 inches works fairly well... One other thing that may force your decision, if you are older, your eyes will likely have lots of "floaters", which are debris that floats around in your eyeballs. This debris floats in and out of the center of your field of view, and looks like a bunch of translucent worms, or shadows. Your brain, the magnificent organ that it is, tries to compensate for your eye's degradation, and as long as your eyes can move about in your field of view, it effectively removes the floaters from the scenes you are viewing. However, if you use a stereo microscope, your eye position is fixed by the very limited amounts of off axis motion that will allow a through optical channel. This lack of off axis motion will emphasize your floaters in a great way, and you will see *every* *single* *one*, clearly, as if it were something you really wanted to view. Some times, the floaters will cover the exact thing you need to see clearly, and you will have to move it off axis by moving it on the microscope stage. The only answer to this problem, is to either have perfect eyes, or to use a microscope where you are looking at a screen, rather than through a pair of oculars. This way, your eyes can dart around, and inspect what they need to see clearly, and the floaters will be ignored by your brain. As far as I know, there is only one optical microscope built this way, and it is the very expensive Mantis. Because of the great expense of flat screen optical microscopes, most modern SMD viewing equipment is going to the trivially cheap method of using a CCD/CMOS color video camera and an LCD screen. You can do a lot with a cheap USB camera mounted to a boom, a fiber optic light source, or a ring light, and a laptop computer to display the image. -Chuck Harris Bob Albert via time-nuts wrote: What are the important parameters regarding purchase of a stereo microscope? I see some on ebay for around $50; are those good? Bob ___ 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] Working with SMT parts.
Hi Bob: I don't think it's so much the stereo microscope as the related equipment. I have a Bausch & Lomb StereoZoom 4 and the dial is always at the lowest setting (0.7dial * 10X objective = 7 power). For another reason I got a Nikon SMZ-U microscope and discovered that it's so tall that it can not be used for SMT work. http://www.prc68.com/I/NikonSMZ-U.html So an important parameter is is length from the eyepiece to the objective. If that get to be long then you can not easily use it. Using an arm type support is very desirable. These have a heavy metal base with an horizontal arm. You can swing the arm over whatever you're working one and easily move the scope up or down as needed. This all done while in a standard chair on a work bench/table. Although an old fashioned illuminator will work, see top photo: http://www.prc68.com/I/SMT.shtml#Mag A ring light is much more convenient (scroll down a little). Also the soldering iron tip to grip distance should be as short as you can get. (1.5" = burned fingers, 0.5" should be better) -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html The lesser of evils is still evil. Original Message What are the important parameters regarding purchase of a stereo microscope? I see some on ebay for around $50; are those good? Bob On Thursday, August 11, 2016 10:00 AM, Didier Juges <shali...@gmail.com> wrote: I concur. I have been using ExpressPCB extensively over the last 2 years with great satisfaction now that it is possible to get Gerber files from them. I typically use the mini board pro service (3 bare boards, 2 sided with solder mask and silk screen) for prototypes and then buy the Gerbers to have production quantities done overseas. The boards are of high quality and the service is very fast at a very reasonable price. The only gotcha with regard to Gerber files is that you can only buy Gerbers for boards that you have actually bought from them, so the process is to buy the prototypes, then if you are happy with those, buy the Gerbers for that design. Didier KO4BB On Tue, Aug 9, 2016 at 3:06 PM, Brooke Clarke <bro...@pacific.net> wrote: Hi: I've had good luck using any of the the ExpressPCB services that include solder mask with surface mount parts where the pitch is 0.05" (half normal DIP) and hand soldering (requires stereo microscope). http://www.prc68.com/I/BTSG.shtml (battery top signal generator) http://www.prc68.com/I/Images/ICS525v1o.jpg http://www.prc68.com/I/SMT.shtml <http://www.prc68.com/I/SMT.shtml> -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html The lesser of evils is still evil. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/m ailman/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] Working with SMT parts.
Hi Didier: Another option is to send the free ExpressPCB files to FAR Circuits for production. This can be very cost effective if you only need a simple circuit. Vias not supported. www.farcircuits.net/EXPRESS%20PCB%20DOC.doc -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html The lesser of evils is still evil. Original Message I concur. I have been using ExpressPCB extensively over the last 2 years with great satisfaction now that it is possible to get Gerber files from them. I typically use the mini board pro service (3 bare boards, 2 sided with solder mask and silk screen) for prototypes and then buy the Gerbers to have production quantities done overseas. The boards are of high quality and the service is very fast at a very reasonable price. The only gotcha with regard to Gerber files is that you can only buy Gerbers for boards that you have actually bought from them, so the process is to buy the prototypes, then if you are happy with those, buy the Gerbers for that design. Didier KO4BB On Tue, Aug 9, 2016 at 3:06 PM, Brooke Clarke <bro...@pacific.net> wrote: Hi: I've had good luck using any of the the ExpressPCB services that include solder mask with surface mount parts where the pitch is 0.05" (half normal DIP) and hand soldering (requires stereo microscope). http://www.prc68.com/I/BTSG.shtml (battery top signal generator) http://www.prc68.com/I/Images/ICS525v1o.jpg http://www.prc68.com/I/SMT.shtml <http://www.prc68.com/I/SMT.shtml> -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html The lesser of evils is still evil. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/m ailman/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] Low cost SDR suitable for phase noise measurement?
Hi Bob: The SDR-IQ has a lower frequency limit of 500 Hz. http://www.prc68.com/I/Bats.shtml#SDRIQ There is a mod that replaces the on board 66 MHz oscillator with one locked to 10 MHz. -- Have Fun, Brooke Clarke, N6GCE http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html The lesser of evils is still evil. Original Message A number of posts have appeared about Zynq SDRs on the "Shera revisited" thread. So, I'd like to ask the more general question: Are there any low cost SDRs that are suitable for measuring phase noise when coupled with a DMTD? I believe what I'm looking for is something with enough bits to work in the audio range down to DC. Yes, I could use a modified sound card, but I'm really looking for something not sound card related. My thought was to use a DMTD with a heterodyne frequency of maybe 5KHz. Bob - AE6RV.com GFS GPSDO list: groups.yahoo.com/neo/groups/GFS-GPSDOs/info ___ 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] Heathkit clock available
Hi Bill: For night viewing ceiling projection clocks are the way to go. I have both very old ones and a new (WWVB) one. http://www.prc68.com/I/Shadow-Clock.shtml -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html The lesser of evils is still evil. Original Message The GC-1000 was the Most Accurate Clock. This new GC-1006 is Most Reliable without mentioning accuracy. The ad says that the standby oscillator can be calibrated by pushing some buttons on the back. Wondering how they do that almost makes me want to buy a simple clock that is $100 per pound. Perhaps there is a motor that turns a tuning capacitor to make the standby oscillator match the line frequency. More likely software changes the number of counts of some inexpensive XO per cycle. I have an alarm clock with 2" seven segment LEDS that I can read without glasses. Its backup oscillator is LC, and somewhat faster than the line. It has carried me through the short outages I've experienced. There's not enough info on what's behind the Santa Cruz rebirth of Heathkit. If I thought they were solid, I'd buy a kit to help prime the pump, so to speak. As it is, I'll be looking for neon-colored seven segment arrays a bit taller than those in the GC-1006. No doubt, there are many schemes for disciplining 60 (or 50) Hz oscillators with 1 PPS. TIA for any helpful comments. Bill Hawkins ___ 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] Safely getting the electrical length of a connected antenna feedline
Hi: Another option is so Google for a "Breakout board" for the IC you're looking to work with. People like Spark Fun, Seed studio, make these. It's a board that holds the chip and the needed accessory parts, but needs something else like an Arduino. -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html The lesser of evils is still evil. Original Message On Tue, Aug 9, 2016 at 9:10 AM, Bob Albert via time-nuts <time-nuts@febo.com> wrote: Yes, a board with the required footprint would be the way to go. Where does one find that? You can have small PCBs made for $3 each. There are places here in the US that will do PCBs for $3/square inch with a one square inch minimum. basicpcb.com sone of these. It is not hard to design a basic "carrier board" that has just one chip's footprint and maybe a decoupling capacitor and a 0.1" header connector. Many times the chip's data sheet will have an example PCB layout you can borrow that will fit in a one square inch board. ___ 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] Working with SMT parts.
Hi: I've had good luck using any of the the ExpressPCB services that include solder mask with surface mount parts where the pitch is 0.05" (half normal DIP) and hand soldering (requires stereo microscope). http://www.prc68.com/I/BTSG.shtml (battery top signal generator) http://www.prc68.com/I/Images/ICS525v1o.jpg http://www.prc68.com/I/SMT.shtml <http://www.prc68.com/I/SMT.shtml> -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html The lesser of evils is still evil. ___ 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] Heathkit clock available
Hi Nick: The GC-1000 was the clock that not only received and was set by WWV (or WWVH) but also had a disciplined oscillator(HFDO) at 3.6 MHz. http://www.prc68.com/I/HeathkitGC1000.shtml Tom: Have you made stability plots for the GC-1000 HFDO? I recently got a Saunders Assoc. 150B Crystal Impedance Meter and the property sticker on the back says Heath Company. I'm guessing they tested some or all of the 3.6 MHz crystals for the GC-1000 to be sure they would "pull" as needed. I'd like to get my hands on a loose one of those to test it. http://www.prc68.com/I/CrystalImpedanceMeters.html -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html The lesser of evils is still evil. Original Message I just got an email announcing this: https://shop.heathkit.com/shop/product/most-reliable-clock-tm-gc-1006-26 They bill it as a "most reliable" clock. From the description it appears to be an AC line disciplined clock with battery backup. I only mention it here because of the periodic discussion of AC line discipline and because I suspect I'm not the only one who remembers the old Heathkit fondly. Sent from my iPhone ___ 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] Effect of EFC noise on phase noise
Hi Rick: My first engineering job was working on Tunnel Diode amplifiers at microwave frequencies (when transistors only worked at audio frequencies). The bias circuit was a 5.1 Volt Zener and a series diode just as your describe for temperature stability. There was also a BALCO (+ temp coefficient) and VEECO (-temp coefficient) resistor for tweaking the temperature response. Note that the operating point on a TD is around 1 volt, i.e. between the peak voltage and the valley voltage. A pot is included to set the stage gain. http://www.prc68.com/I/Aertech.shtml#TDA <http://www.prc68.com/I/Aertech.shtml#TDA> When I worked at HP in the Kobe Instrument Division (component test instruments) they had the 4352 VCO tester. It was used in conjunction with one of the low phase noise frequency synthesizers that typically has a "two man lift" sticker and the production line had small cranes to lift them. The programmable DC (EFC) supply was specially designed to have a very low noise level. It's the same programmable supply that is an option on the 4395A. I sure would like to find one of those to add to my 4395A. http://www.prc68.com/I/4395A.shtml -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html The lesser of evils is still evil. Original Message Around 35 years ago, I worked with the guys who designed and manufactured the 10811. There are a couple of things here that don't add up, subject to remembering stuff from a LONG time ago: 1. Back in those days at least, there were vendors who supposedly specialized in providing low noise zener diodes. The particular breakdown voltage of zener diodes was important. IIRC, at low voltages, it is a true "zener" diode and at higher voltage it is merely an avalanche diode. The physics are somehow different. There is also a "magic" voltage where the tempco happens to be +2mV/degree C, in which case you can cancel it out with a series junction diode. I believe they even sold combination diodes with both the zener and the temperature compensation diode in one package. 6.4V is not far from the magic voltage, FWIW. Anyway, what I was led to believe is that certain JEDEC 1N___ part numbers, with suffixes indicating noise properties, from particular vendors had much lower than average noise. Thus if a run of the mill zener diode has 1,000's of nV/sqrtHz of noise, these "golden" diode might have only 100's, or even dozens. At one time I had some copies of some fairly detailed lab notebook pages detailed research by engineers that I have a lot of confidence in. 2. In all the work with 10811's, E1938A's, and the 5071A, there was never any indication that the zener diode and associated resistors, etc made any contribution whatsoever to phase noise or Allan deviation. If there was any such effect, I can guarantee that we would have heard about "hero experiments" proving it, and we would see 10811's with "EFC-ectomies" used as references in phase noise and AD test systems. An indication of the level of scrutiny during the 10811 design, I submit 2 examples: there is a 10 Meg resistor across the crystal that supposedly prevents DC charge from building up in the crystal due to cosmic ray hits There was an extensive witch hunt that found ultimately that lubricating oil in the piston trimmer migrated around and caused "aging". I'm not sure what the fix was other than not lubricating the cap. Maybe a different type of oil. Rick On 8/3/2016 7:11 AM, Charles Steinmetz wrote: One further point regarding noise from the EFC voltage: The varactor in the oscillator will necessarily have a rather high resistance in series with it, which adds a certain amount of unavoidable Johnson noise. Also, the "other end" of the varactor is not generally grounded -- rather, it is connected (through a high-ish resistance) to an internal reference voltage, which has its own noise. Taking the HP 10811 as an example, one end of the varactor is connected to an internal +6.4v reference through 100k ohms, and the other is connected to the external EFC voltage, also through 100k ohms. The resistors alone set a noise density floor of about 90nV/sqrtHz at the oven temperature, while even a "low noise" 6.4V zener diode operated at 1mA has a noise density in the low thousands of nV/sqrtHz (in this case, filtered by 11k ohms and 6.8uF). The filter has a LP characteristic with a corner frequency of ~2Hz, but (1) the noise below that frequency is still a very real concern for phase noise, and (2) it's only a one-pole filter, so the 10Hz noise is still in the 1000nV/sqrtHz range. The point of all this? The external EFC voltage doesn't have to be heroically quiet to remove it as a practical source of phase noise. That said, be careful about radiated fields and poor PSRR inducing or coupling voltages onto the EFC line -
Re: [time-nuts] Adafruit Ultimate GPS timing message arrival times
Hi Mark: Isn't this the receiver that hears a very large number of GNSS satellites and also has a 10 Hz update rate? If so, I'd expect that there would a large variation in message lengths. How stable is the 10 PPS or 1 PPS output? -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html The lesser of evils is still evil. Original Message A couple of people have asked about the poor message arrival time performance of the popular Adafruit Ultimate GPS receiver. I modified Lady Heather to analyze the message arrival times using a histogram instead of a simple average. When I looked at the histogram data (.01 msec resolution), I was rather shocked... With an hour of data, most receivers have maybe a couple dozen bins hit, with the peak bin several hundred counts above the next lower peak. The Adafruit had over 1800 bins hit, with the peak bin having six hits. Attached is the histogram... you probably don't want to use this receiver to drive a clock based upon message arrival times... ___ 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] Very Accurate Delta Time RF Pulse
Hi Jerome: Some time ago a company called Opto Electronics made a frequency counter with a small antenna that would count the frequency of a nearby signal. They call these Near Field Receivers. Some modern scanner radios incorporate some of these ideas. http://www.prc68.com/I/BC125AT.html -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html The lesser of evils is still evil. Original Message Thank you all who responded including Bob, Attila, Vlad, Brooke, and Chris for some great suggestions. This is a fun side project of mine to passively detect RF emitters based upon strongest nearby signal using ToA pulses from cheap log power sensors or perhaps the Watson-Watt method. The hope is to use it in a vehicle with sufficient antenna spacing and time pulse accuracy to create a neighborhood plot with strongest TX locations. Yes, there are major issues to be overcome. The super wide band input has no tuner and will pickup massive noise from many near-field sources, such as wi-fi, Bluetooth, or phones, however some can be filtered as noise. Additionally, very few omni antennas cover such a large input range and I don't think CW signals will be detected properly, as they don't use a distinct rising-edge pulse. I'm leaning toward what Bob suggested with a single shot Ghz counter possibly with some type of pulse start/stop timer or a double input A/D with GS/s buffers that can be stopped and momentarily read off whenever a new strong signal is detected or after a set time each second. Vlad mentioned a phase comparator AD8302, which would also be interesting and allow for analog or possibly digital wideband multi-frequency comparison using phase. The AD8302 apparently comes with its own internal double log power RF input, which could save on purchasing additional power sensor ICs as well. Best Regards, -Jerome ___ 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] Very Accurate Delta Time RF Pulse Measurements
Hi Jerome: The Vietnam era Radar Warning Systems used 4 wide band antennas (nose, tail & wing tips) and displayed the bearing, rough distance & threat type on a CRT. Near the antenna was a crystal video receiver using a multi channel filter driving Schottky diode detectors. The output from each detector fed a video log amp. http://www.prc68.com/I/RWR.shtml http://www.prc68.com/I/ALR54.shtml The Fenwick antenna patent based on time delay beam steering is far superior to a phased array in that it's frequency independent. http://www.prc68.com/I/Ant.shtml#TDBS I think the basis of TOA. Can you say more about the specifics of what you are trying to do? -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html The lesser of evils is still evil. Original Message Hi Guys, This is a little outside of time-nuts scope, but not by much. I'm interested in finding the time between two rising edges above a set threshold with preferably nS or high ps timing accuracy. Can this be simply done with a few programmed Microchip PICs or with a good short term OCXO clock? The issue I see is that a 10Mhz timing reference with 1 cycle difference in time yields 100ns resolution, which is far too large, so maybe a PIC can solve this. This weekend project would be a multi-element antenna array, each with a super-fast response log peak power detector fed into several PICs for time of arrival. Whenever a nearby high energy RF pulse is detected, the time of arrival between two antenna elements and hence the direction toward the TX could be roughly computed. Some typical log peak detectors have an 8ns input pulse response time, so I'm hoping that rise times are similar between multiple detectors, negating the delayed response. There are time of arrival/AoA systems out there with synthetic doppler, phased arrays, correlative interferometers, and phase comparators, but it would be interesting to accomplish super wideband AoA timing on two rising pulses with relatively cheap parts. Thanks, -Jerome ___ 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] Q/noise of Earth as an oscillator
Hi Hal: I resemble that remark. Momentum and drift. It's interesting that the drift rate depends on the physical volume. See table at: http://www.prc68.com/I/Sensors.shtml#Gyroscopic http://www.prc68.com/I/Gyroscopes.html -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html The lesser of evils is still evil. Original Message att...@kinali.ch said: I am not sure you can apply this definition of Q onto earth. Q is defined for harmonic oscillators (or oscillators that can be approximated by an harmonic oscillator) but the earth isn't oscillating, it's rotating. While, for time keeping purposes, similar in nature, the physical description of both are different. What do gyroscope-nuts use to describe the quality of their toys? ___ 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] The home time-lab
Hi Chris: The APC RS1500 uses what they call modified sine wave, but I call modified square wave, i.e. it's a square wave with a couple of parts that are at zero volts. Don Lancaster promoted "Magic Sinewaves" where a pulse modulated waveform drives an H-bridge. The leading and trailing edges are determined using the idea of FFT so that all the harmonics up to some number (typically 9 to thirty something) are zero. There were also 3-phase versions. But he no longer sells any hardware. PS I'm looking for a source of 3-phase 400 Hz 115 VAC to power a North Finding Gryo. http://www.prc68.com/I/WildARK2.html -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html The lesser of evils is still evil. Original Message Yes, "ferroresonant" is also called CVT. Typically rather than buying just the transformer you buy a box that has one in it but also some other components to clip spikes (some MOVs) and and LC low pass filter. I know it seems a saturated core might produce a non-sine wave but current CVTs have very low distortion. The other option is an on-line UPS, one that always runs off the battery. These are expensive if you need a good sine wave output. The UPS has an output stage not unlike an audio amplifier. Not nearly as efficient as MOSFET switches. (question: I'd guess that modern versions would be designed with class-D output stages and have decent power efficiency??) The best solution is what the phone companies did. The telco style equipment, like computers and such runs off 48VDC. and batteries are connected in parallel from a "battery room". If designing your own GPSDO, it should be built to run of 12V battery power. For AC the best solution is a motor generator. Basically an iron flywheel rides out any small dropouts in the utility power. They had one for a mainframe computer at a place I worked at a long time ago. But only that one output 280V at 400Hz as the computer required 400Hz power. On Mon, Jul 25, 2016 at 2:43 AM, David J Taylor <david-tay...@blueyonder.co.uk> wrote: Chris, Do you mean like these: http://www.aelgroup.co.uk/products/agt.php I have an old 75W unit somewhere ___ 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] The home time-lab
Hi Bill: I have links to the Sola patents at: http://www.prc68.com/I/Sola_CVS.html#Patents The 1939 patent shows a single gap and the resonant circuit, but the current patent (number on Sola xformer label) shows two gaps and the resonant circuit. They specify up to a 3 ms dropout restoration which implies the amount of energy stored is enough to last that long. A full time UPS (one where the line is converted to battery voltage then battery voltage is converted to a sine wave) could be expected to have a clean output. But a relay switched UPS, like mine, does nothing to the line waveform, so the Sola offers a lot of improvement. Since the Sola does not help getting a sine waveform, it may be better to put it on the input since that might make dropout detection more reliable? -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html The lesser of evils is still evil. Original Message Years ago I knew exactly how Sola regulators worked. That has faded, but what remains is that the regulation was done by varying the saturation of the core. That's why there is a slot in the laminations. I find it hard to believe that a partially saturated core can produce zero harmonics. In any event, the LC circuit does not filter anything. Possibly the circuit counteracts the change in saturation as the line voltage changes. I wouldn't expect it to effect the high frequency components of spikes. Any power supply that has a diode bridge and capacitor to create DC only draws power from the line at the voltage peaks, when the diodes become forward biased. I don't know of any choke input supplies, as were used to reduce the peak current of vacuum tube rectifiers. I know nothing about power factor correction for a bridge and capacitor, whether or not it is followed by a switching regulator. Make of it what you will. Bill Hawkins -Original Message- From: Alex Pummer Sent: Sunday, July 24, 2016 7:29 PM That is interesting, since the Sola device has a to the line frequency tuned tank circuit in it, thus the output should not have to many higher harmonics and should look reasonable close to sinusoidal see here: http://www.rdrelectronics.com/russ/jun16/vs2.PDF 73, K6UHN Alex ___ 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] The home time-lab
Hi David: Yes, the computer, monitor, and DSL modem, switch, answering machine were connected. I haven't remembered how to run the DSO in the short time the self test lasts. AC VRMS line= 117, AC VRMS UPS = 114. -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html The lesser of evils is still evil. Original Message On Sun, 24 Jul 2016 14:45:02 -0700, you wrote: Hi Bob: The Sola 500 VA transformer is specified to hole up the line voltage for 3 ms. (but not a half cycle of the line frequency). I've connected the Sola CVS transformer to the output of the APC RS1500 backup UPS. (needed to replace the 2 batteries in the main unit and probably within a year the 4 batteries in the optional battery pack. http://www.prc68.com/I/Sola_CVS.html http://www.prc68.com/I/PC.shtml#Backup_UPS The Sola transformer is connected to the output of the RS1500. This will clean up any spikes or narrow drop outs on the AC line since when the AC line is active the UPS does nothing. My hope was that the transformer would clean up the modified square wave output of the UPS, but that does not happen. Video of APC self test showing waveform on scope:https://youtu.be/DLE0mzAt7KY <https://youtu.be/DLE0mzAt7KY> Was the Sola transformer under load when you ran the test? I thought a minimum load was a requirement for proper operation. Maybe it is time to get an online UPS or power conditioner but then you would not need the constant voltage transformer. Was the peak voltage still 170 volts? If so then maybe it does not matter. Capacitive input loads and PFC power supplies should not care. I think the modified square wave killed my HP 6200 flat bed scanner. The best scanner I've used and no longer made. Ouch. That is not suppose to happen but apparently some switching power supplies have problems with modified sine outputs even though they should not. I have been told a couple of times that PFC power supplies are even more likely to have problems with modified sine inverters but I have yet to find an in depth discussion of the problem. The PFC stage should work with any input wave shape. ___ 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] The home time-lab
Hi Bob: The Sola 500 VA transformer is specified to hole up the line voltage for 3 ms. (but not a half cycle of the line frequency). I've connected the Sola CVS transformer to the output of the APC RS1500 backup UPS. (needed to replace the 2 batteries in the main unit and probably within a year the 4 batteries in the optional battery pack. http://www.prc68.com/I/Sola_CVS.html http://www.prc68.com/I/PC.shtml#Backup_UPS The Sola transformer is connected to the output of the RS1500. This will clean up any spikes or narrow drop outs on the AC line since when the AC line is active the UPS does nothing. My hope was that the transformer would clean up the modified square wave output of the UPS, but that does not happen. Video of APC self test showing waveform on scope:https://youtu.be/DLE0mzAt7KY <https://youtu.be/DLE0mzAt7KY> I think the modified square wave killed my HP 6200 flat bed scanner. The best scanner I've used and no longer made. -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html The lesser of evils is still evil. Original Message I hope this isn't too far off topic, as this is having a big impact on my testing. I decided to run an A/B test on one of my GPSDOs: comparing the phase of the two 10MHz output channels. In the middle of the night, there was a long series of 35ns pops in the phase data. Strangely enough, there was nothing in the data collected directly from the unit involved. The preceding two days we had had a number of switching transients where the lights blinked but nothing shut down. So, putting one and one together, I suspect that a fair percentage of the strange results I've been getting has been power-grid related. So, what to do? I've been looking at UPS devices, and I don't even understand enough to waste my money on a bad one. The two big questions seem to be "on-line" and "sine wave". Make that three: can I trust the mfgs claims? Is there something affordable that could run a pair of 5370s and maybe another 50W worth of DUTs for up to an hour or two and not be prey to power-line transients? Or would it be more cost effective to somehow monitor the power line for spikes or phase jumps and blow off tests or cut out the offending data? From time to time we get a thread on power-line nuts. Should I have been paying more attention? Bob - AE6RV --- GFS GPSDO list: groups.yahoo.com/neo/groups/GFS-GPSDOs/info ___ 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] LSEM (Leap Second Every Month)
Hi Tom: I'm not worried about a single second, but rather an accumulation of them over many years leading to making sundials obsolete. The map is centered on China (PS the Chinese symbol for china is a circle with a vertical line i.e. China is the center of the world) and all of China is on the same time, they don't use time zones. Northern California looks pretty good. Where I live there's a lot of solar panels because we get a lot of sun. Almost all the corrections you mention are built into heliochronometers. I made a Noon mark by driving a brass tack into a hardwood floor at exactly noon. After a few years you could see a group of three close together tacks for each day because of the effect of leap years. http://www.prc68.com/I/Sundial.shtml#Indoor_analemma Yes, you need to know where on Earth you are in order to tell what time it is when using the sun. I spent some time (TM: intended pun) looking into a way to use optical means to measure the Earth's period and the limit is optical "seeing" which can amount to a few arc seconds of angle. http://www.prc68.com/I/StellarTime.shtml But I'm not convinced that a single optical observation defines the limit of precision. For example a fixed telescope could time stamp each star meridian crossing and that data could be correlated with the known star positions to come up with an averaged meridian crossing time. That would improve the accuracy by SQRT(# stars). So you might improve the single shot observation error of 66 ms to maybe a hand full of ms. More than one fixed telescope could be used, I asked a scientist who works with the satellites that measure sea level how they can get the stated accuracy and the answer was what I'd call massive averaging N=(tens of thousands). I have a number of aircraft navigation instruments (Navigation, surveying & time are all areas I'm interested in) and the MD1 Astro Compass may be able to track a star when mounted on a B-52 to better than 1 arc minute of angle. I suspect better if mounted on a concrete pier on the ground. I've been told when mounted that way for testing it could detect the deformation of the earth caused by a truck a mile away. http://www.prc68.com/I/MD1.shtml It's a marvel of mechanical and optical engineering. The sad thing is that the Air Force seems to burn all the manuals for obsolete equipment. So far I have not been able to determine the electrical connections for the MD1. -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html The lesser of evils is still evil. Original Message Hi Brooke, About sundials, timezones and "precise" timekeeping ... There's a wonderful map by Stefano Maggiolo that everyone should look at: http://blog.poormansmath.net/images/SolarTimeVsStandardTime.png "How much is time wrong around the world?" http://blog.poormansmath.net/how-much-is-time-wrong-around-the-world/ Someone mentioned the effect of leap seconds on true solar time. Based on the map, it's pretty common for civil noon (based on UTC) to be as much as an hour or more different from solar noon. Part of that is timezones. Part of that is DST. Part of that is seasonal, as in the equation of time (EoT). Given that, a +/-1 second offset due to a leap second is lost in the noise. In fact according to my EoT calculator the offset for today is 300 s and tomorrow its 309 s. So even one day's worth of EoT is ten times more than a leap second. I would be interested in Sun dials too, maybe even a solar disciplined oscillator (SoDO), except most weeks it would be in holdover mode up here in the Northwest. ;-) The PID code would be quite interesting, since you can forward predict EoT. I think this is something Mike Cook would want to build, yes? One other calculation for you: Earth circumference is 40,000 km. At 45 degrees latitude it's cos(45) = 0.707 as much. So an hour error from noon is 700 miles; a minute is 12 miles; a second is 1000 feet; and 1 ms is 1 foot; just like the speed of sound. That means a leap second is equivalent to walking 1000 feet, while DST is being forced marched 700 miles. /tvb ----- Original Message - From: "Brooke Clarke" <bro...@pacific.net> To: "Discussion of precise time and frequency measurement" <time-nuts@febo.com> Sent: Friday, July 22, 2016 12:16 PM Subject: Re: [time-nuts] LSEM (Leap Second Every Month) Hi Tom: One of my interests is in Sun dials, so I like the idea of civil time corresponding as close as possible to the Sun's position. Heliochronometers can be accurate to some seconds. The Dent <http://www.prc68.com/I/Dent.shtml>Dipleidoscope <http://www.prc68.com/I/Dent.shtml> was used to set railroad clocks based on the Sun's position. Another area of interest is astronomy where UTC1 adds a correction to a tenth of a second to UTC that essentially bridges the
Re: [time-nuts] LSEM (Leap Second Every Month)
Hi Tom: One of my interests is in Sun dials, so I like the idea of civil time corresponding as close as possible to the Sun's position. Heliochronometers can be accurate to some seconds. The Dent <http://www.prc68.com/I/Dent.shtml>Dipleidoscope <http://www.prc68.com/I/Dent.shtml> was used to set railroad clocks based on the Sun's position. Another area of interest is astronomy where UTC1 adds a correction to a tenth of a second to UTC that essentially bridges the gap between the leap second corrections. It would be interesting to learn how the Software Bisque Paramount telescope mount handles time. It does not have any provision for a time nuts oscillator/clock, but maybe should? -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html The lesser of evils is still evil. Original Message If UTC time was adjusted every month would stick with one full second? Or some smaller quantity? Hi Scott, The LSEM month suggestion retains the UTC policy of leaps being exactly +1 or -1 second, never larger, never smaller. There's a world of hurt if anyone even dreamed of shifting UTC by a fraction of a second. In fact, one of the main reasons UTC was created in the 70's was to put an end to the dreaded fractional jumps in atomic timekeeping during that era. Fractional steps atomic frequency and fractional steps in atomic time were both tried during 60's. For example: http://www.leapsecond.com/history/wwvb1966.htm Eliminating frequency jumps completely (by defining the UTC second to be 9,192,631,770 Hz cesium), and changing any steps to be full +1 or -1 second integers (and not fractions) was why UTC was created. /tvb - Original Message - From: "Scott Stobbe" <scott.j.sto...@gmail.com> To: "Discussion of precise time and frequency measurement" <time-nuts@febo.com> Sent: Thursday, July 21, 2016 3:06 PM Subject: Re: [time-nuts] LSEM (Leap Second Every Month) If UTC time was adjusted every month would stick with one full second? Or some smaller quantity? On Thursday, 21 July 2016, Brooke Clarke <bro...@pacific.net> wrote: Hi Tom: I like this idea. I addresses the lesson from Y2K that something done often works much better than something done only occasionally. That's way you see the firetruck at the local store, because it's used all the time and so is more likely to work when needed. -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html The lesser of evils is still evil. Original Message Hi Tom... Does your proposal allow for a Zero leap second, or does it require either plus or minus 1 to work? Seems like you could stay closer to the true value if you also have a zero option. Might also cause less consternation for some services, like the finance and scientific worlds, that seem to have critical issues when an LS appears. I like your point that by having it occur monthly it forces systems to address issues promptly, and maybe that's the argument for the non-zero option. Tom Holmes, N8ZM -Original Message- From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Tom Van Baak Sent: Thursday, July 21, 2016 1:28 PM To: Discussion of precise time and frequency measurement < time-nuts@febo.com> Cc: Leap Second Discussion List <leaps...@leapsecond.com> Subject: Re: [time-nuts] Leap second to be introduced at midnight UTC December 31 this year Time to mention this again... If we adopted the LSEM (Leap Second Every Month) model then none of this would be a problem. The idea is not to decide *if* there will be leap second, but to force every month to have a leap second. The IERS decision is then what the *sign* of the leap second should be this month. Note this would keep |DUT1| < 1 s as now. UT1 would stay in sync with UTC, not so much by rare steps but by dithering. There would be no change to UTC or timing infrastructure because the definition of UTC already allows for positive or negative leap seconds in any given month. Every UTC-aware device would 1) know how to reliably insert or delete a leap second, because bugs would be found by developers within a month or two, not by end-users years or decades in the future, and 2) every UTC-aware device would have an often tested direct or indirect path to IERS to know what the sign of the leap second will be for the current month. The leap second would then become a normal part of UTC, a regular monthly event, instead of a rare, newsworthy exception. None of the weird bugs we continue to see year after year in leap second handling by NTP and OS's and GPS receiver firmware would occur. Historical leap second tables would consist of little more than 12 bits per year. Moreover, in the next decade or two or three, if we slide into an era where average earth rotation slows from 86400.1 to 86400.0 to 86399.9 seconds a
[time-nuts] LSEM (Leap Second Every Month)
Hi Tom: I like this idea. I addresses the lesson from Y2K that something done often works much better than something done only occasionally. That's way you see the firetruck at the local store, because it's used all the time and so is more likely to work when needed. -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html The lesser of evils is still evil. Original Message Hi Tom... Does your proposal allow for a Zero leap second, or does it require either plus or minus 1 to work? Seems like you could stay closer to the true value if you also have a zero option. Might also cause less consternation for some services, like the finance and scientific worlds, that seem to have critical issues when an LS appears. I like your point that by having it occur monthly it forces systems to address issues promptly, and maybe that's the argument for the non-zero option. Tom Holmes, N8ZM -Original Message- From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Tom Van Baak Sent: Thursday, July 21, 2016 1:28 PM To: Discussion of precise time and frequency measurement <time-nuts@febo.com> Cc: Leap Second Discussion List <leaps...@leapsecond.com> Subject: Re: [time-nuts] Leap second to be introduced at midnight UTC December 31 this year Time to mention this again... If we adopted the LSEM (Leap Second Every Month) model then none of this would be a problem. The idea is not to decide *if* there will be leap second, but to force every month to have a leap second. The IERS decision is then what the *sign* of the leap second should be this month. Note this would keep |DUT1| < 1 s as now. UT1 would stay in sync with UTC, not so much by rare steps but by dithering. There would be no change to UTC or timing infrastructure because the definition of UTC already allows for positive or negative leap seconds in any given month. Every UTC-aware device would 1) know how to reliably insert or delete a leap second, because bugs would be found by developers within a month or two, not by end-users years or decades in the future, and 2) every UTC-aware device would have an often tested direct or indirect path to IERS to know what the sign of the leap second will be for the current month. The leap second would then become a normal part of UTC, a regular monthly event, instead of a rare, newsworthy exception. None of the weird bugs we continue to see year after year in leap second handling by NTP and OS's and GPS receiver firmware would occur. Historical leap second tables would consist of little more than 12 bits per year. Moreover, in the next decade or two or three, if we slide into an era where average earth rotation slows from 86400.1 to 86400.0 to 86399.9 seconds a day, there will be zero impact if LSEM is already in place. /tvb ___ 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] The home time-lab
Hi Bob: A resonate transformer may solve your problem. I added one to my first computer, See Fig 1. http://www.prc68.com/I/comp.shtml#SWTP http://www.prc68.com/I/Images/SWTP-01b.jpg The oval shaped silver can oil capacitor is connected to a winding on the transformer and resonates at 60 Hz. Think of it as a filter centered at 60 Hz and as an energy storage device. This removes line spikes and fills in narrow line drop outs. https://en.wikipedia.org/wiki/Voltage_regulator#Constant-voltage_transformer Here are models with capacities of: 300, 600, 1200 & 1800 VA: http://www.hammondmfg.com/CVR.htm Just search for "Constant-voltage transformer". -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html The lesser of evils is still evil. Original Message I hope this isn't too far off topic, as this is having a big impact on my testing. I decided to run an A/B test on one of my GPSDOs: comparing the phase of the two 10MHz output channels. In the middle of the night, there was a long series of 35ns pops in the phase data. Strangely enough, there was nothing in the data collected directly from the unit involved. The preceding two days we had had a number of switching transients where the lights blinked but nothing shut down. So, putting one and one together, I suspect that a fair percentage of the strange results I've been getting has been power-grid related. So, what to do? I've been looking at UPS devices, and I don't even understand enough to waste my money on a bad one. The two big questions seem to be "on-line" and "sine wave". Make that three: can I trust the mfgs claims? Is there something affordable that could run a pair of 5370s and maybe another 50W worth of DUTs for up to an hour or two and not be prey to power-line transients? Or would it be more cost effective to somehow monitor the power line for spikes or phase jumps and blow off tests or cut out the offending data? From time to time we get a thread on power-line nuts. Should I have been paying more attention? Bob - AE6RV --- GFS GPSDO list: groups.yahoo.com/neo/groups/GFS-GPSDOs/info ___ 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] Longitude
Hi Richard: Also a movie with the same title. An even bigger problem was finding the latitude. Book: Latitude by Carter & Carter http://www.prc68.com/I/UkiahObs.shtml -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html The lesser of evils is still evil. Original Message There is a really good book about the man who won the British Admiralty prize for constructing and testing an accurate clock for determining longitude at sea. “Longitude: The True Story of a Lone Genius Who Solved the Greatest Scientific Problem of His Time,” by Dava Sobel (Author). Richard ___ 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] Heliostat
Hi: I recently got an Eastern Science Supply Co. demonstration heliostat, that's to say it's small enough to easily hand hold. I've go it working but have some questions. Based on some Waterbury Clock Co. patents I think is was made in the late 1920s or early 1930s. ESSCo was into astronomy. I got a book they published "A Manual of Laboratory Astronomy, for use in introductory courses by Harlan True Stetson Phd, 1928 - but no mention of the heliostat. http://www.prc68.com/I/ESSCoHeliostat.html The base has level vials and an elevation scale for the clockwork driven lower mirror that's clearly calibrated in latitude. The lower (clockwork driven) mirror has a pointer to a scale divided into 24 hours, one half black and the other half white. I'm guessing that in order to properly setup this heliostat you need to know the local mean solar time, i.e. correct for Daylight savings, EOT and your offset from the time zone meridian. That way you could preset the time then rotate the base and tilt the lower mirror until the sun's image was centered on the top mirror. For now I sort of pointed it at north and adjusted both the lower mirror tilt and the time setting to get the sun along the axis of rotation. Were heliostats also used for looking at stars? i.e. could the Fast-Slow clock adjustment be used to make the clock work for either solar or sidereal time? -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html The lesser of evils is still evil. ___ 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] Cable length calibration
Hi Mike: For quite a while I was heavily into "chirp" transmissions. These are HF ionosphere radio transmissions that sweep from 2 to 30 MHz at 100 kHz/sec. In order to "tune" the radio to a specific station (you can not tune by frequency) you need to know the start time schedule for that specific station (time nuts content). When GPS became popular the transmitters switched to GPS. http://www.prc68.com/I/RCS-5A.shtml You can use a pulse of RF to calibrate the time delay through your HF receiver to get a more accurate time of reception value. That helps because with a GPS synchronized transmitter you can determine it's great circle distance from you. Under some conditions you can see a transmission going around the Earth 2 or 3 times. In a similar way if you used a pair non amplified versions of a GPS antenna back to back you could determine the time delay of the pair and then divide by two. -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html The lesser of evils is still evil. Original Message Le 29 juin 2016 à 22:18, Poul-Henning Kamp <p...@phk.freebsd.dk> a écrit : In message <20160629192850.19c29406...@ip-64-139-1-69.sjc.megapath.net>, Hal Mu rray writes: At one point they were looking into making a GPS time receiver where the cable length calibration would be built-in. How would you do that? TDR ? If it wasn't behind a choke, the inrush current to the antenna preamp power filtering capacitor could be measured, but the choke ruins that. The trouble is how to do it without frying the antenna preamp... Seriously... GPS antennas and receivers are cheap, I would just use two GPS antennas with a known difference in cable-length. Sounds simple, but even after a days reflection I don’t see how you find the complete path delay. You would get the cable delay (OPs concern) provided they were the same antenna/cable type combinations, but not delay induced by the antenna electronics. From another post that delay seems to be non-negligable. I find it curious that antenna manafacturers don’t seem to give this parameter. I looked at some datasheets on Trimble and Leica sites but they don’t have it. As for me, I measure cable delay by injecting a 1PPS into it through a T and for the RG174 attached to the patch antennas, just sacrificed one by cutting the head off and measuring that. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 p...@freebsd.org | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. ___ 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. "The power of accurate observation is commonly called cynicism by those who have not got it. » George Bernard Shaw ___ 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] Cable length calibration
Hi Hal: I think the cal process is essentially a time domain reflection measure of cable length. The GPS receiver and the cable cal hardware would be in the antenna unit. The 1 PPS signal would be aligned at the output of the cable. -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html The lesser of evils is still evil. Original Message bro...@pacific.net said: At one point they were looking into making a GPS time receiver where the cable length calibration would be built-in. How would you do that? The obvious way is to compare the time you get with a known-good time, but if you had that, why would you want this new GPS with an unknown cable length. You might be able to do it by measuring the DC drop. Getting enough accuracy seems tough. ___ 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] buying a time interval counter
Hi Stephane: I traded my HP 53132A counter for an SR 620. The 53132 has what I'd call a user hostile interface, so if you are manually controlling the counter the SR 620 has a huge advantage. I also like the long display on the 620 which can be read from across the room. PS Stanford Research is a company founded by physicists and makes some really high quality stuff. In fact some of the products HP/Agilent/Keysight sells are repackaged SR instruments. http://www.prc68.com/I/TandFTE.shtml#SR620 The claim to fame for the HP 53132A is that it can make a frequency (not time interval) measurement to 1E12 in a second. Here's how to get that same result with the SR620: http://www.prc68.com/I/FTS4060.shtml#SR620Fast On the down side the printing functions on the 620 require an Epsom printer. Does anyone have a solution for that? PS SR also makes a 10 MHz crystal oscillator that has options trading stability for aging as well as the EFC tuning polarity and range so as to match other OCXOs. http://prc68.com/I/TandFTE.shtml#SC10 At one point they were looking into making a GPS time receiver where the cable length calibration would be built-in. -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html The lesser of evils is still evil. Original Message Hello there, I'm planning to buy a such instrument in order to do some frequency stability measurement at work. The SR620 seems to be discontinued. What model still distributed would you think is good for that at the moment ? Thanks & cheers Stephane ___ 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] How to properly characterize 32kHz oscillators manually and with a microcontroller?
Hi David: I built a number of clocks based on PIC uC and using interrupts. The idea is to use the output from a frequency standard as the heart beat of the clock. Depending on what the PIC was doing when interrupted the delay can different by one cycle and a simple test corrects that. Clock settable to 1ms and keeps perfect time. http://www.prc68.com/I/PRC68COM.shtml#07092006 I wrote this directly using the Microchip assembler. I'm not a fan of C. My first uC was the SWTP kit that came with no software. I learned to write directly in hex machine language. The problem with that is every time code is changed inside a loop the target address needs to be recomputed. Later I got a copy of the Motorola assembler and editor which was a big help. http://www.prc68.com/I/comp.shtml#SWTP -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html The lesser of evils is still evil. Original Message O M G.. So I followed the link and saw how they do it.Wow. They write interrupts like the DMV processes applications. I can only imagine what this looks like on the PIC, where every instruction takes 4x as many cycles. All of that pushing and popping is PRECISELY what you need to avoid. Pushing any register that the ISR does not actually change is totally insane. My average ISR is far shorter than their intro and outro code. "C" does not cooperate easily with this, but you can declare your interrupts "naked" and write them in assembler so as to avoid this insanity. I say this as someone who has been developing on the AVR platform for something like 20 years. My first application was on the 8515, and they didn't even have production silicon yet. My development was done on a chip with date code "ES" (Engineering Sample) ___ 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] OT stuffing boards: was GPS interface/prototyping board
Hi: For IC pitches of 0.050" (1.27mm) hand soldering works fine, even for my vision when a stereo microscope is used. Elmer's glue to hold the chips is place. Getting boards from ExpressPCB that have solder mask helps to prevent bridging. Here is an example: http://www.prc68.com/I/BTSG.shtml -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html The lesser of evils is still evil. ___ 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] A little telegraph history, slightly off topic
Hi Mitch: Thanks for the post. I'd like to see you video on adjusting a bug. -- Have Fun, Brooke Clarke, N6GCE http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html The lesser of evils is still evil. Original Message A little history about telegraphy and identifying operators and transmitters. As the former owner of Vibroplex (1994-2009) I spoke with thousands of hams and hundreds of former railroad and WU telegraphers at hamfests over the years, many at the Dayton, OH hamfest. Also, one of my friends was Harold Kaplan, W4KVO (sk), who was a Signal Core intercept operator in WWII. Harold spent three years in Newfoundland copying high speed German telegraphy. The monitoring station had rhombic antennas aimed at the North Atlantic, Europe, Africa, and the South Atlantic, with banks of Hammarlund receivers, state of the art at the time. The Germans had mylar tape recorders (Ampex after the war), they recorded code at 35-40 wpm, 5 letter code groups, and retransmitted the code at 70-100 wpm. The Signal Core recorded the German transmissions on wire recorders, slowed the code down to 30-40 wpm to copy and put the copied 5 letter code groups on a landline teletype circuit to a decryption facility. Some of the operators could copy the code directly off the wire recorder at 50-60 wpm straight to the teletype without having to transcribe! Of course, the intercept operators were copying 5 letter code groups for many hours a day, for months on end. They became very proficient. Harold related to me how they could identify individual German operators sending the code, and occasionally would get personal information on the operators and their locations when the operators would chat with each other. They assigned all of the German operators nicknames, based on the particular operator’s “fist” and the characteristics of their transmitter. So even with a new German operator, the characteristics of the transmitter ‘sound’ could give away the transmitter location. As a new general class ham in 1963, I joined Army Mars – that was how I met Harold. The first thing the local Mars director did to a new member was assign them as net control for a cw net. And, what a way to get your code speed up. Some of the net members would ‘check in’ to the net at 20-25 wpm, some at 50-60 wpm, almost all using Bugs. As the protocol of the net was fixed, you could muddle through as net control if you could copy at ~20 wpm. However, it only took a couple of months and you were up to at least 30-35 wpm for self preservation. Also, by the time a net member sent their first character or two of code, you knew who the member was. Identification was a combination of the operator’s fist, and the characteristics of their transmitter. There would be a slight signal chirp, key click, power supply hum, etc. etc. on the signal. All of the transmitters were tube, of course, and they all sounded a little different. The old time hams and telegraphers who came by the Vibroplex booth at hamfests always stopped to chat and send a few characters on one of the display bugs. And every single one of them would say, “this bug needs adjusting”, and proceed to make adjustments. That is one of the reasons each operator sounded different on the air, their bug was adjusted just the way they liked it. I spend a lot of time readjusting bugs! A favorite diversion of mine was to have a left handed display bug. People would come up to the display, not notice that the bug was left handed, and try to send with it. They would complain, something is wrong with this bug. I would reach across the table, the bug being ‘right hand’ for me and send a few characters, and say no, this bug is just fine. Not many people left who know how to properly adjust a bug, it is a simple 1, 2, 3. I need to make a YouTube video on how to do it. J Mitch W4OA ___ 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] Measuring receiver...
Hi Alan: I've read that prior to 7 Dec 1941 we were able to identify both radio operators (by their "fist") and radios by serial number. So we could tell that Joe was not on his usual ship and by using DF we knew where that ship was located. -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html The lesser of evils is still evil. Original Message TX "fingerprinting" in WWII You seem to be forgetting that there were very few of the sophisticated digital timing systems were available 75 years ago. Traffic analysis was started early in 1938 or even before. By 1939 we knew all the nets used in Europe and had "Y" ( a corruption of WI, Wireless Intercept )operators monitoring the nets. Many of these were amateurs and they were allocated to specific nets and followed them around as they moved. They became very familiar with the "accents" of operators on their nets, and particularly before 1939 security procedures were very lax and "chatting" common-place.but it was all aural. I suspect serious transmitter parameter logging was not done before the cold war when spectrum analysers, or at least pan-adapters became more readily available. To keep a little OnTopic .you would have difficulty doing this with a BC-221.!! :-)) A crystal clock of this period was at least one fully utilised 6foot 19inch rack (there is one at Grenwich.) Alan G3NYK Alan G3NYK - Original Message - From: "jimlux" <jim...@earthlink.net> To: <time-nuts@febo.com> Sent: Tuesday, June 21, 2016 10:02 PM Subject: Re: [time-nuts] Measuring receiver... On 6/21/16 11:28 AM, Brooke Clarke wrote: Hi: During W.W.II there were secret methods of "fingerprinting" radio transmitters and separately the operators. I suspect the transmitter fingerprinting involved things like frequency accuracy, stability, CW rise and decay time, For the operator some from of statistics on the timings associated with sending Morse Code. But. . . I haven't seen any papers describing this. Can anyone point me to a paper on this? For "human controlled" stuff, e.g. recognizing someone's "fist", there's a huge literature out there on biometric identification looking at things like keyboard and mouse click timing - the timing requirements are pretty slack, and hardly time-nuts level, unless you're looking to do it with mechanical devices constructed from spare twigs and strands of kelp. There have been a variety of schemes for recognizing individual radios by looking at the frequency vs time as they start up. Likewise, it's pretty easy to distinguish radar magnetrons from each other. Not a lot of papers about this, but you'll see it in advertising literature, or occasionally in conference pubs (although I can't think of any off hand). There was someone selling a repeater access control system that was based on the transmitter fingerprint. But the real reason why you don't see any publications is that this stuff is pretty classic signals intelligence (SIGINT or MASINT) and it is still being used, and is all classified. You're not relying on Betty the receiver operator to recognize the characteristic chirp as the agent's radio is keyed, it's all done by computer now, but the basic idea is the same. And as with most of this stuff, the basics are well known, but the practical details are not, or, at least, are the proprietary secret sauce in any practical system. (In a significant understatement, Dixon, in "Spread Spectrum Systems" makes some comment about how synch acquisition is the difficult part and won't be described in the book) You might look at the unclassified proceedings of conferences like MILCOM and find something. Googling with MASINT might also help. ___ 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] Measuring receiver...
Hi: During W.W.II there were secret methods of "fingerprinting" radio transmitters and separately the operators. I suspect the transmitter fingerprinting involved things like frequency accuracy, stability, CW rise and decay time, For the operator some from of statistics on the timings associated with sending Morse Code. But. . . I haven't seen any papers describing this. Can anyone point me to a paper on this? -- Have Fun, Brooke Clarke, N6GCE http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html The lesser of evils is still evil. Original Message Nick, Welcome to the world of FMT-Nuttery where we strive to make absurdly accurate off-air frequency measurements. I regularly participate in the FMT's. The "measuring receiver" I use is a HP-3586B "Selective Level Meter". While the 3586 series of receivers will only give you 0.1 Hz resolution, there are simple methods to use them to get down to 1 mHz (milliHertz) resolution, or better. You'll quickly find out that you're limited by propagation between the FMT transmitter and your receive location. Rather than go into a long dissertation here on how to do this, here's a link to the write-up for my preferred FMT Methodology - K6OQK FMT Methodology. See: http://www.k5cm.com/k6oqk%20fmt%20new.htm You're probably already familiar with Connie, K5CM's website for all things FMT, but in case you're not, take a look at: www.k5cm.com I'll be glad to answer any questions you have. You can either ask here or send me a direct e-mail at: b...@att.net. Burt, K6OQK From: Nick Sayer <nsa...@kfu.com> I'm considering taking a shot at the next ARRL frequency measurement contest. The assumption going in is that the signal is CW, with at least a half minute or so of just solid "on" at one point or another and that reception is reasonably good. I've got a good TIA and excellent references, but that's the easy part, it seems to me. It seems to me that what I really need to do is make a synthesized heterodyne receiver that can present an accurately tuned RF band pass - say, 10 kHz wide with the synthesizer set for 5 kHz steps - to the TIA, with some manually tunable high-pass and low-pass filtering to isolate the signal of interest. If the mixer got its LO from a synthesizer with a GPSDO reference, it seems to me that you could then measure the frequency of the signal of interest (now an audio frequency, so you can listen to it too) with the TIA (also getting the GPSDO reference) and then do simple math to arrive at the actual RF frequency. Anybody have any thoughts? Burt I. Weiner Associates Broadcast Technical Services Glendale, California U.S.A. b...@att.net www.biwa.cc 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.
[time-nuts] THE Original Time Interval Counter
Hi: The stopwatch: 200 years old and still ticking http://www.gizmag.com/birthday-200th-stopwatch/43431/? -- Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html The lesser of evils is still evil. ___ 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.
