Re: [time-nuts] Low noise power supplies?
Are 4 and 5 regulated? Or is the zener picked to compensate for the VBE drops? Any of these circuits where the output transistor is in an emitter follower configuration will have its noise effected by the load current, since that current directly effects the output transistor transconductance. The load in all cases was a couple hundred mA worth of resistance at the voltage in question, as I recall. It's been a few years since I captured these plots. The Zeners were just whatever parts came to hand, 1N474x parts basically. I didn't care about the 1.4V drop across the Darlington, just the resulting noise. -- john Miles Design LLC ___ time-nuts mailing 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] question for expert time guys
rickhar...@gmail.com said: I would like to triangulate a position of a device which moves using 3 fixed positions devices of known location. The idea is to have these operate on 915mhz or 434mhz or 2.4ghz or appropriate frequency. I'd like a range of 150 feet or better and accuracy of 3 feet or better. I know the time accuracy is the key to count time = feet, 1ns. How to make it inexpensive is key. how inexpensive, very ;-) I think it's going to be tough to do it at low cost. The low cost transmit/receive chip sets you can get for 915 MHz are low bandwidth. That will turn into noise on the on/off transition that you need for timing. I'd suggest getting a pair of demo boards and running some experiments. The first simple sanity check would be to wire them up to a couple of uProcs and send messages and see if they work at your required range. Play around to learn the error rate vs baud rate. -device response ASAP on different frequency Not with low cost. But you don't need to use a second frequency. My straw man would be something like this: Only one station transmits at a time. Wire up the transmit and receive lines to counter/timers. On both the transmit and recv side, grab the time on each data-level change and average them to figure out when the packet started. Look at the NTP protocol. It collects 4 time stamps. From that, you can compute the time of flight. The time at the remote server drops out. The sequence would be something like this: fixed-remote: long timing packet. (with lots of 1/0 transitions to feed data to the timer hardware) remote-fixed: long timing packet. remote- fixed: packet with 2 time stamps first from the receive side, second from the transmit side I'd put a CRC on the packets as a sanity check. Handwave time: Assume the counter/timers run at 100 MHz. That's 10 ns. So you'll have to do lots of averaging to get below 3 ns. But that's assuming the RF units work well and that the averaging works. You could build a (much) faster counter/timer in a FPGA. I'm not sure that will help. Get a pair (or 2 pairs) of units and see how well they work. I'd expect FSK to work slightly better than ASK (on/off), but I'm not enough of an RF geek to turn than into numbers. I'll say more if that will help. We should probably take it off list. One probably crazy idea... Setup a directional antenna with a motor to aim it. Scan for the best signal. -- These are my opinions. I hate spam. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] question for expert time guys
and even a more crazy idea: use a phasing array for the directional antenna. On Fri, Feb 1, 2013 at 10:45 AM, Hal Murray hmur...@megapathdsl.net wrote: rickhar...@gmail.com said: I would like to triangulate a position of a device which moves using 3 fixed positions devices of known location. The idea is to have these operate on 915mhz or 434mhz or 2.4ghz or appropriate frequency. I'd like a range of 150 feet or better and accuracy of 3 feet or better. I know the time accuracy is the key to count time = feet, 1ns. How to make it inexpensive is key. how inexpensive, very ;-) I think it's going to be tough to do it at low cost. The low cost transmit/receive chip sets you can get for 915 MHz are low bandwidth. That will turn into noise on the on/off transition that you need for timing. I'd suggest getting a pair of demo boards and running some experiments. The first simple sanity check would be to wire them up to a couple of uProcs and send messages and see if they work at your required range. Play around to learn the error rate vs baud rate. -device response ASAP on different frequency Not with low cost. But you don't need to use a second frequency. My straw man would be something like this: Only one station transmits at a time. Wire up the transmit and receive lines to counter/timers. On both the transmit and recv side, grab the time on each data-level change and average them to figure out when the packet started. Look at the NTP protocol. It collects 4 time stamps. From that, you can compute the time of flight. The time at the remote server drops out. The sequence would be something like this: fixed-remote: long timing packet. (with lots of 1/0 transitions to feed data to the timer hardware) remote-fixed: long timing packet. remote- fixed: packet with 2 time stamps first from the receive side, second from the transmit side I'd put a CRC on the packets as a sanity check. Handwave time: Assume the counter/timers run at 100 MHz. That's 10 ns. So you'll have to do lots of averaging to get below 3 ns. But that's assuming the RF units work well and that the averaging works. You could build a (much) faster counter/timer in a FPGA. I'm not sure that will help. Get a pair (or 2 pairs) of units and see how well they work. I'd expect FSK to work slightly better than ASK (on/off), but I'm not enough of an RF geek to turn than into numbers. I'll say more if that will help. We should probably take it off list. One probably crazy idea... Setup a directional antenna with a motor to aim it. Scan for the best signal. -- These are my opinions. I hate spam. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing 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] question for expert time guys
Also the fixed stations can not have OCXO? On Fri, Feb 1, 2013 at 5:37 AM, Rick Harold rickhar...@gmail.com wrote: To time experts/EE's. I would like to triangulate a position of a device which moves using 3 fixed positions devices of known location. The idea is to have these operate on 915mhz or 434mhz or 2.4ghz or appropriate frequency. These two type of devices (fixed and mobile) are all under my control and thus customized as needed. The mobile device (not a phone, custom device) would be the least expensive item. I'd like a range of 150 feet or better and accuracy of 3 feet or better. When manufactured these items they can be calibrated in order to adjust for any variation in IC's, discrete components etc... We can assume for now the temperature is constant 70 degree temperature. Cost is the key design factor. The general flow is: 1. base station 1 indicates we are determining position of device A. 2. Each base station 1, 2, 3 take turns pinging the device to determine distance. 3. A ping consists of (something like, e.g. frequencies as examples) -send 915mhz signal from base station to device -device response ASAP on different frequency -station waits and counts 'time' for return -this is repeated N? times to get best avg/accuracy. -The mobile device does not move very fast 4. Since delays of the process on each unit is calibrated the device and base station would subtrack that time out from the results. 5. obviously with 3 distances we can determine the 2D position of the mobile device I know the time accuracy is the key to count time = feet, 1ns. This overall project is not new concept. How to make it inexpensive is key. how inexpensive, very ;-) no OCXO or expensive components like that. That's my goal, and I'm looking for help on the design/thought process of getting there. I am open to a consulting arrangement for a fee, please email if you like. I've worked with 'regular' EE's (I'm a software guy) but this time accuracy is too much for them. Esp. finding a way to do it inexpensively. Thanks for any thoughts. ___ time-nuts mailing 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] question for expert time guys
Hi Rick, You would do better putting a small GPS receiver in the mobile and transmit with a 2.4 GHz Blue tooth transmitter. The GPS devices can be gotten very small (your thumb would just about cover it up). They are also very light and draw very little power. That would save you two transmitting and receiving stations. Clearly the software would be infinitely easier as you would not need to deal with all the timing issues. GPS would provide the position information and its time count for each report, if that mattered. Some representative GPS receivers can be research at the following location: https://www.sparkfun.com/categories/4 They also have various transmitter devices for blue tooth, WIFI and Zigbee. You can view these under the following category: https://www.sparkfun.com/categories/16 This is only one place that provides such things for hobbyist. There are others, as well as, going direct to the manufacturers for such OEM products. I do not know if you are aware of it, but and finale product that transmits over the air may need FCC certification. Other sections might apply in certain circumstances. BillWB6BNQ Rick Harold wrote: To time experts/EE's. I would like to triangulate a position of a device which moves using 3 fixed positions devices of known location. The idea is to have these operate on 915mhz or 434mhz or 2.4ghz or appropriate frequency. These two type of devices (fixed and mobile) are all under my control and thus customized as needed. The mobile device (not a phone, custom device) would be the least expensive item. I'd like a range of 150 feet or better and accuracy of 3 feet or better. When manufactured these items they can be calibrated in order to adjust for any variation in IC's, discrete components etc... We can assume for now the temperature is constant 70 degree temperature. Cost is the key design factor. The general flow is: 1. base station 1 indicates we are determining position of device A. 2. Each base station 1, 2, 3 take turns pinging the device to determine distance. 3. A ping consists of (something like, e.g. frequencies as examples) -send 915mhz signal from base station to device -device response ASAP on different frequency -station waits and counts 'time' for return -this is repeated N? times to get best avg/accuracy. -The mobile device does not move very fast 4. Since delays of the process on each unit is calibrated the device and base station would subtrack that time out from the results. 5. obviously with 3 distances we can determine the 2D position of the mobile device I know the time accuracy is the key to count time = feet, 1ns. This overall project is not new concept. How to make it inexpensive is key. how inexpensive, very ;-) no OCXO or expensive components like that. That's my goal, and I'm looking for help on the design/thought process of getting there. I am open to a consulting arrangement for a fee, please email if you like. I've worked with 'regular' EE's (I'm a software guy) but this time accuracy is too much for them. Esp. finding a way to do it inexpensively. Thanks for any thoughts. ___ time-nuts mailing 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] question for expert time guys
Hi Rick, You would do better putting a small GPS receiver in the mobile and transmit with a 2.4 GHz Blue tooth transmitter. The GPS devices can be gotten very small (your thumb would just about cover it up). They are also very light and draw very little power. That would save you two transmitting and receiving stations. Clearly the software would be infinitely easier as you would not need to deal with all the timing issues. GPS would provide the position information and its time count for each report, if that mattered. Some representative GPS receivers can be research at the following location: https://www.sparkfun.com/categories/4 They also have various transmitter devices for blue tooth, WIFI and Zigbee. You can view these under the following category: https://www.sparkfun.com/categories/16 This is only one place that provides such things for hobbyist. There are others, as well as, going direct to the manufacturers for such OEM products. I do not know if you are aware of it, but and finale product that transmits over the air may need FCC certification. Other sections might apply in certain circumstances. BillWB6BNQ Rick Harold wrote: To time experts/EE's. I would like to triangulate a position of a device which moves using 3 fixed positions devices of known location. The idea is to have these operate on 915mhz or 434mhz or 2.4ghz or appropriate frequency. These two type of devices (fixed and mobile) are all under my control and thus customized as needed. The mobile device (not a phone, custom device) would be the least expensive item. I'd like a range of 150 feet or better and accuracy of 3 feet or better. When manufactured these items they can be calibrated in order to adjust for any variation in IC's, discrete components etc... We can assume for now the temperature is constant 70 degree temperature. Cost is the key design factor. The general flow is: 1. base station 1 indicates we are determining position of device A. 2. Each base station 1, 2, 3 take turns pinging the device to determine distance. 3. A ping consists of (something like, e.g. frequencies as examples) -send 915mhz signal from base station to device -device response ASAP on different frequency -station waits and counts 'time' for return -this is repeated N? times to get best avg/accuracy. -The mobile device does not move very fast 4. Since delays of the process on each unit is calibrated the device and base station would subtrack that time out from the results. 5. obviously with 3 distances we can determine the 2D position of the mobile device I know the time accuracy is the key to count time = feet, 1ns. This overall project is not new concept. How to make it inexpensive is key. how inexpensive, very ;-) no OCXO or expensive components like that. That's my goal, and I'm looking for help on the design/thought process of getting there. I am open to a consulting arrangement for a fee, please email if you like. I've worked with 'regular' EE's (I'm a software guy) but this time accuracy is too much for them. Esp. finding a way to do it inexpensively. Thanks for any thoughts. ___ time-nuts mailing 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 noise power supplies?
Bob Camp, Thursday, January 31 11:36 AM (Local NY time): ((...snip...)) With a good enough voltmeter you could carry the analogy one step further and compute an ADEV like number on the output voltage. I suspect that's carrying things a bit far. No, I disagree. That's not carrying things nearly far enough. I really think we should figure out a reliable methodology for this sort of thing. This is time nuts after all, so perhaps some time/frequency applications might end up needing sub-nanovolt regulation (and there are those whom might simply need it because they're nuts) Tom Van Baak, Thursday, January 31, 2013 9:43 AM (Local NY time): ((...snip...)) I was never quite satisfied with the outcome of comparing a half dozen power supplies this way: http://www.leapsecond.com/pages/tbolt/noise.htm We have rigorous ways to compare and report oscillator performance; both as numbers and as plots. Is there something equivalent for power supplies? Thanks Tom. I found that writeup about various power supplies rather useful. I'm doing some research and development for power supplies right now, and hope to come up with something completely nuts by the time I'm ready to go from learning how to work with thunderbolts / GPS Disciplined OCXO to something exotic which, today, might be far over my head. --Sarah ___ time-nuts mailing 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 noise power supplies?
Hi Bert, No need to block the DC. These instruments already have DC blocks (and a switchable low current DC sink to hold the line from the exchange) because the telephone line has a DC voltage of typically 48V on it already. For comparison I just use 600 ohm termination and dBm, dBmV can be calculated or use a look-up table. To compare a batch you can zero the meter on the first or known good unit and just read the delta. Robert G8RPI. From: Burt I. Weiner b...@att.net To: time-nuts@febo.com Sent: Thursday, 31 January 2013, 19:19 Subject: [time-nuts] Low noise power supplies? Bob, I have a pair of HP-3551A's*. I'm very familiar with making transmission lines measurements, and it seems that measuring power supply noise would be the same, except that you want to block the DC from the input of the instrument. What has your procedure been and what numbers have you come up with? Since these instruments read in dBm0, do you reference from the supply's voltage and then convert to mV (difference)? * One that I picked up off eBay for $75.00 looks new and came with the complete manual, and the battery will run it most of the day. Thanks, Burt, K6OQK Subject: Re: [time-nuts] Low noise power supplies? A non-standard but repeatable way to measure power supply noise is to use a Transmission Impairment Measuring Set (TIMS) such as the HP3945(6)A or 3551 (2)A. These were intended for use in pairs to assess analog telephone lines for data use. As well as an AF generator, frequency counter, amplifier, monitor speaker and level meter they will measure broadband noise. Being designed for POTS they will also withstand at least 50V DC at the input while measuring the noise. You can also apply internal filters if required. The last digit designates a North American? (BELL) or European (CCITT) standard unit, but broadband noise is the same. They can be picked up really cheaply now (list was$3000-$5000) and make a nice compact audio test set. Robert G8RPI. 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.
Re: [time-nuts] Low noise power supplies?
Hi The circuit I described, is (as stated) quiet down to 100 Hz. It's 3 db bandwidth is well below 10 Hz with the 47 uF cap. If you need it quiet down to 10 Hz or 0.1 Hz, you will need to buy a few more caps. It's still not rocket science. For most OCXO or atomic standard testing applications out there, 10 Hz is low enough. Bob On Jan 31, 2013, at 9:41 PM, Charles P. Steinmetz charles_steinm...@lavabit.com wrote: Bob wrote: An AD 797, a couple of metal film resistors, and a fairly large (say 47 uf) plastic cap work pretty well. The band from 10 Hz down to 0.1 or 0.01 Hz is generally important when testing oscillators. To keep the 797 input noise density below a few nV per root Hz, the terminations must have very low resistance. With such low resistance, a 47 uF cap won't even get you to 10 Hz, much less 0.1 or 0.01 Hz. One more thought: Many oscillators have internal regulators that are not nearly as good as what you can build. No sense using an external supply with 5 nV per root Hz noise density if it will be re-regulated inside the oscillator by a circuit that has a noise density of 250 nV per root Hz. Best regards, Charles ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Low noise power supplies?
Linear Technology application note 83 Performance Verification of Low Noise, Low Dropout Regulators holds some interesting information. I am however unsure whether what was low noise in 2000 is still low noise in 2013 Best regards Ulrich Bangert -Ursprungliche Nachricht- Von: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] Im Auftrag von Bob Camp Gesendet: Freitag, 1. Februar 2013 13:38 An: Discussion of precise time and frequency measurement Betreff: Re: [time-nuts] Low noise power supplies? Hi The circuit I described, is (as stated) quiet down to 100 Hz. It's 3 db bandwidth is well below 10 Hz with the 47 uF cap. If you need it quiet down to 10 Hz or 0.1 Hz, you will need to buy a few more caps. It's still not rocket science. For most OCXO or atomic standard testing applications out there, 10 Hz is low enough. Bob On Jan 31, 2013, at 9:41 PM, Charles P. Steinmetz charles_steinm...@lavabit.com wrote: Bob wrote: An AD 797, a couple of metal film resistors, and a fairly large (say 47 uf) plastic cap work pretty well. The band from 10 Hz down to 0.1 or 0.01 Hz is generally important when testing oscillators. To keep the 797 input noise density below a few nV per root Hz, the terminations must have very low resistance. With such low resistance, a 47 uF cap won't even get you to 10 Hz, much less 0.1 or 0.01 Hz. One more thought: Many oscillators have internal regulators that are not nearly as good as what you can build. No sense using an external supply with 5 nV per root Hz noise density if it will be re-regulated inside the oscillator by a circuit that has a noise density of 250 nV per root Hz. Best regards, Charles ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing 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 noise power supplies?
Hello, interesting discussion about noise. It's all way over my knowledge, so my contribution to discussion maybe is only noise :) Re batteries I agree with Mark, see below: Il 2013-01-31 06:42 Mark Sims ha scritto: A123 20Ah LiFePO4 cells have an internal resistance in the milliohm range. Their M1 26650 format cells are around 8 milliohms. Most high capacity (3000 mAh) 18650 style lithium cells are around 10-15 milliohms. I made some tests of high rate RC batteries, and their internal resistance seem to be below 10mOhm These are Li-ion pouch cells, their selfdischarge seem very low, but I dont have figures for this. Their cost is very low, and are used for RC airplanes or cars, only thing I'm expecting is that they will age and their internal resistance (and capacity) probably will worsen after some time. This is a graph of a 3-cell battery of 1.8Ah capacity, charged and discharged at 3.6A and 7.2A (red and blue curves): http://www.eevblog.com/forum/reviews/high-rate-li-ion-batteries/?action=dlattach;attach=31097 Here tested up to maximum declared rate: http://www.eevblog.com/forum/reviews/high-rate-li-ion-batteries/?action=dlattach;attach=31185 I report this here about noise, because I remember that while I was charging and discharging them, I was watching with awe the voltmeter stable readings. The power supply/load was an HP6632B and the meter a keithley 2015, the meter reading was stable up to last digit (10uV over 10-11V)and counting digit by digit up while charging or down while discharging, no missing codes sort of thing :) It was like watching a counter instead of a voltmeter. So I was wondering what could be the real noise of a chemical battery. Reading this discussion I'm learning that the batteries can be low noise voltage sources. Thanks, Fabio. ___ time-nuts mailing 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 at 60,000 feet
I was just surprised it locked at that speed. I figured a handheld unit would not be able to lock at that speed. Looking back on it now, it makes sense it shouldn't have too much trouble. (Once I learned it worked I started to ask about the GPS more. If you ask politely, a lot of times they will let you turn on stuff once at altitude, which is great fun!) Now you have me thinking. Anyone know what the Garmin GPSMAP60CS and GPSMAP62ST use for gps chip sets? (For some reason I just can't bring myself to pull the covers off!) Dan On 1/31/2013 5:01 PM, time-nuts-requ...@febo.com wrote: I think it's supposed to work up there. Cocom limits used to be 50,000 feet and 1000 knots if I am not mistaken. Most GPS will likely support those Cocom limits even if they state something like 2000 meters max altitude etc. A commercial flight should certainly work, besides the problem of only seeing one side of the sky on the plane.. bye, Said ___ time-nuts mailing 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] Low noise power supplies?
Joe, I'm using that in my low power (150ma) supplies. I add a zener to the base (darlington) circuit for pre-regulation. Since I'm doing a line operated linear supply the fall off of gain with frequency is not of too much concern. Once I finish testing (I have boards in hand - I need to order parts) I will publish. Simon Message: 6 Date: Thu, 31 Jan 2013 15:39:02 -0500 From: Joe Leikhim jleik...@leikhim.com To: time-nuts@febo.com Subject: [time-nuts] Low noise power supplies? Message-ID: 510ad666.8090...@leikhim.com Content-Type: text/plain; charset=ISO-8859-1; format=flowed Back when I was in product engineering there was a VCO design that used a superfilter circuit. It consisted of a pass transistor and a filter cap from base to ground. The gain of the transistor multiplied the effective capacitance. I have not seen this configuration since. -- Joe Leikhim Leikhim and Associates Communications Consultants Oviedo, Florida jleik...@leikhim.com 407-982-0446 WWW.LEIKHIM.COM Engineering is the art of making what you want from what you can get at a profit. ___ time-nuts mailing 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 at 60,000 feet
On 1/31/13 1:09 PM, Chris Albertson wrote: I know for sure my handheld Garmin works at 27000 feet, at 530mph... ...I was actually surprised it worked up there. It made me wonder what the actual limits are. What are the limits of your hand held unit or what are the limits of GPS in general. I think GPS works as long as you are under the orbit of the satellites. The company I used to work for placed GPS on some low orbit spacecraft, so say roughly 200 miles up and 18,000 mph but I'd guess most hand held units would not work in those conditions GPS will even (maybe) work at the Moon: with a gain antenna pointed back at earth.. you're looking at the satellites on the opposite side of the earth radiating around the limb. I don't know that anyone has actually tried it but it's certainly been analyzed to death. The potential problem with a handheld GPS in space (depending on where you are) would be whether you can keep track of the constellation and acquire new s/v's fast enough with lots o'Doppler. You already have to deal with the Doppler from the S/Vs buzzing around at 3-4 km/sec. Whether your receiver can handle the extra 7 km/sec Doppler in LEO is a good question. 7 km/sec is about 20 ppm, and I suspect that the receiver can already deal with that much change in the oscillator frequency. It might be doppler rate that it would have a hard time with (because the designer cranked down on the loop bandwidth for noise reasons) What are those folks flying GPS on CubeSats using? ___ time-nuts mailing 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 noise power supplies?
Hi If you use an electrolytic cap on the base (tantalum or what ever) the leakage current will mess up the output a bit. It does *eventually* die down some, but you may have to wait for days... Bob -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of M. Simon Sent: Friday, February 01, 2013 9:11 AM To: time-nuts@febo.com; jleik...@leikhim.com Subject: [time-nuts] Low noise power supplies? Joe, I'm using that in my low power (150ma) supplies. I add a zener to the base (darlington) circuit for pre-regulation. Since I'm doing a line operated linear supply the fall off of gain with frequency is not of too much concern. Once I finish testing (I have boards in hand - I need to order parts) I will publish. Simon Message: 6 Date: Thu, 31 Jan 2013 15:39:02 -0500 From: Joe Leikhim jleik...@leikhim.com To: time-nuts@febo.com Subject: [time-nuts] Low noise power supplies? Message-ID: 510ad666.8090...@leikhim.com Content-Type: text/plain; charset=ISO-8859-1; format=flowed Back when I was in product engineering there was a VCO design that used a superfilter circuit. It consisted of a pass transistor and a filter cap from base to ground. The gain of the transistor multiplied the effective capacitance. I have not seen this configuration since. -- Joe Leikhim Leikhim and Associates Communications Consultants Oviedo, Florida jleik...@leikhim.com 407-982-0446 WWW.LEIKHIM.COM Engineering is the art of making what you want from what you can get at a profit. ___ time-nuts mailing 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] question for expert time guys
Can the base stations be interconnected via cable? In that case, wouldn't it suffice to have the mobile device send an unmodulated carrier of low enough frequency, and compare the phase between the receiving base stations, taking the (known) cable delays into account? Cheers Stefan Rick Harold wrote: To time experts/EE's. I would like to triangulate a position of a device which moves using 3 fixed positions devices of known location. The idea is to have these operate on 915mhz or 434mhz or 2.4ghz or appropriate frequency. These two type of devices (fixed and mobile) are all under my control and thus customized as needed. The mobile device (not a phone, custom device) would be the least expensive item. I'd like a range of 150 feet or better and accuracy of 3 feet or better. When manufactured these items they can be calibrated in order to adjust for any variation in IC's, discrete components etc... We can assume for now the temperature is constant 70 degree temperature. Cost is the key design factor. The general flow is: 1. base station 1 indicates we are determining position of device A. 2. Each base station 1, 2, 3 take turns pinging the device to determine distance. 3. A ping consists of (something like, e.g. frequencies as examples) -send 915mhz signal from base station to device -device response ASAP on different frequency -station waits and counts 'time' for return -this is repeated N? times to get best avg/accuracy. -The mobile device does not move very fast 4. Since delays of the process on each unit is calibrated the device and base station would subtrack that time out from the results. 5. obviously with 3 distances we can determine the 2D position of the mobile device I know the time accuracy is the key to count time = feet, 1ns. This overall project is not new concept. How to make it inexpensive is key. how inexpensive, very ;-) no OCXO or expensive components like that. That's my goal, and I'm looking for help on the design/thought process of getting there. I am open to a consulting arrangement for a fee, please email if you like. I've worked with 'regular' EE's (I'm a software guy) but this time accuracy is too much for them. Esp. finding a way to do it inexpensively. Thanks for any thoughts. ___ time-nuts mailing 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] question for expert time guys
On 1/31/13 8:37 PM, Rick Harold wrote: To time experts/EE's. I would like to triangulate a position of a device which moves using 3 fixed positions devices of known location. The idea is to have these operate on 915mhz or 434mhz or 2.4ghz or appropriate frequency. These two type of devices (fixed and mobile) are all under my control and thus customized as needed. The mobile device (not a phone, custom device) would be the least expensive item. I'd like a range of 150 feet or better and accuracy of 3 feet or better. When manufactured these items they can be calibrated in order to adjust for any variation in IC's, discrete components etc... We can assume for now the temperature is constant 70 degree temperature. Cost is the key design factor. Don't do pinging and time of flight. Do phase measurements. At 900 MHz the wavelength is 33cm. Essentially rather than trying to ping, you're measuring the positions of multiple zero crossings averaged over some amount of time. Can your base stations be interconnected so they can share a common reference signal? What position accuracy do you need? How big an area? Can you initialize at a known position and then track, or do you need to come up cold? There's a lot of clever schemes that use multiple frequencies from a common source to disambiguate phase: e.g. if I measure phase at 908 MHz and phase at 928 MHz, I can effectively also measure phase as if I were radiating at 20 MHz, so that gives me coarse position (out of 15m wavelength) and fine position (out of 33cm wavelength) ___ time-nuts mailing 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] question for expert time guys
Just to make sure I understand the 'ground rules', the three base stations define a plane, unless they are on the same line. Is the mobile device also in this plane? How far apart are the base stations relative to the location of the mobile device? Or, better, is the mobile device 'inside' this triangle or 'outside'? How precisely can you know the location of the base stations without violating the 'inexpensive' rule? Can the base stations 'ping' each other? Seems to me that an accuracy to 3 feet is going to be a problem without precise time measurement unless you can use some 'known' reference (like the precise location of the base stations) and the ability to use that 'known' to 'calibrate' each measurement, thus minimizing the errors from 'drift', etc., in the available, 'inexpensive', time references. Good luck. Joe -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Rick Harold Sent: Thursday, January 31, 2013 10:37 PM To: time-nuts@febo.com Subject: [time-nuts] question for expert time guys To time experts/EE's. I would like to triangulate a position of a device which moves using 3 fixed positions devices of known location. The idea is to have these operate on 915mhz or 434mhz or 2.4ghz or appropriate frequency. These two type of devices (fixed and mobile) are all under my control and thus customized as needed. The mobile device (not a phone, custom device) would be the least expensive item. I'd like a range of 150 feet or better and accuracy of 3 feet or better. When manufactured these items they can be calibrated in order to adjust for any variation in IC's, discrete components etc... We can assume for now the temperature is constant 70 degree temperature. Cost is the key design factor. The general flow is: 1. base station 1 indicates we are determining position of device A. 2. Each base station 1, 2, 3 take turns pinging the device to determine distance. 3. A ping consists of (something like, e.g. frequencies as examples) -send 915mhz signal from base station to device -device response ASAP on different frequency -station waits and counts 'time' for return -this is repeated N? times to get best avg/accuracy. -The mobile device does not move very fast 4. Since delays of the process on each unit is calibrated the device and base station would subtrack that time out from the results. 5. obviously with 3 distances we can determine the 2D position of the mobile device I know the time accuracy is the key to count time = feet, 1ns. This overall project is not new concept. How to make it inexpensive is key. how inexpensive, very ;-) no OCXO or expensive components like that. That's my goal, and I'm looking for help on the design/thought process of getting there. I am open to a consulting arrangement for a fee, please email if you like. I've worked with 'regular' EE's (I'm a software guy) but this time accuracy is too much for them. Esp. finding a way to do it inexpensively. Thanks for any thoughts. ___ time-nuts mailing 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] Loran again
89700 dana and the srs700 has been locked for 10 hours plus. Looking pretty good comparing RB adjusted to gps and 20ns drift will be at least 42 minutes. But just relooked at the drift and it may be much longer. SN in Boston 49db gain 33db margin. HP 3801 is warming up for a direct comparison. Regards Paul WB8TSL On Fri, Feb 1, 2013 at 12:30 AM, Stan, W1LE stanw...@verizon.net wrote: Fired up the SRS FS700 and auto found the GRI 89700 microsecond stations in Dana Il (master) and Seneca NY, (slave) both with equal signal strength of 63 db. Other slaves were not to be found. Noise margin of 32 dB and Rx gain of 72dB. So the Rx is all locked up. Tomorrow I will have more data comparing the 10 MHz from the T'Bolt. Right now they are comparing to within 10EE10. Stan, W1LE Cape Cod On 1/31/2013 10:44 PM, Stan, W1LE wrote: What GRI should we be listening for ? Stan, W1LECape Cod FN41sr On 1/31/2013 9:56 PM, paul swed wrote: Rich indeed its on the air. Warming up the FS700 to see if it will lock. Have a pattern ram thats getting flakey and takes about 30 minutes to warm up along with the oven. __**_ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/** mailman/listinfo/time-nutshttps://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-nutshttps://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] Loran again
Still locked onto the Dana/Seneca Loran stations at 8:38 am local. Comparison to GPS/DO is about the same. No new slaves detected. Stan, W1LECape Cod On 2/1/2013 12:30 AM, Stan, W1LE wrote: Fired up the SRS FS700 and auto found the GRI 89700 microsecond stations in Dana Il (master) and Seneca NY, (slave) both with equal signal strength of 63 db. Other slaves were not to be found. Noise margin of 32 dB and Rx gain of 72dB. So the Rx is all locked up. Tomorrow I will have more data comparing the 10 MHz from the T'Bolt. Right now they are comparing to within 10EE10. Stan, W1LE Cape Cod On 1/31/2013 10:44 PM, Stan, W1LE wrote: What GRI should we be listening for ? Stan, W1LECape Cod FN41sr On 1/31/2013 9:56 PM, paul swed wrote: Rich indeed its on the air. Warming up the FS700 to see if it will lock. Have a pattern ram thats getting flakey and takes about 30 minutes to warm up along with the oven. ___ time-nuts mailing 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] GPS at 60,000 feet
ITAR limits are AND. If it is below 50,000 ft OR below 1000 knots, it will work. My Garmin GPS60CSx has always worked on commercial flights at 40,000 ft and 500 MPH. We use commercial Trimble units on our scientific balloons that go up to 120,000 ft (38 km). David McGaw NASA BARREL project Systems Engineer Dartmouth College On 2/1/13 9:14 AM, Jim Lux wrote: On 1/31/13 1:09 PM, Chris Albertson wrote: I know for sure my handheld Garmin works at 27000 feet, at 530mph... ...I was actually surprised it worked up there. It made me wonder what the actual limits are. What are the limits of your hand held unit or what are the limits of GPS in general. I think GPS works as long as you are under the orbit of the satellites. The company I used to work for placed GPS on some low orbit spacecraft, so say roughly 200 miles up and 18,000 mph but I'd guess most hand held units would not work in those conditions GPS will even (maybe) work at the Moon: with a gain antenna pointed back at earth.. you're looking at the satellites on the opposite side of the earth radiating around the limb. I don't know that anyone has actually tried it but it's certainly been analyzed to death. The potential problem with a handheld GPS in space (depending on where you are) would be whether you can keep track of the constellation and acquire new s/v's fast enough with lots o'Doppler. You already have to deal with the Doppler from the S/Vs buzzing around at 3-4 km/sec. Whether your receiver can handle the extra 7 km/sec Doppler in LEO is a good question. 7 km/sec is about 20 ppm, and I suspect that the receiver can already deal with that much change in the oscillator frequency. It might be doppler rate that it would have a hard time with (because the designer cranked down on the loop bandwidth for noise reasons) What are those folks flying GPS on CubeSats using? ___ time-nuts mailing 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 at 60,000 feet
What are those folks flying GPS on CubeSats using? I do believe they roll their own. Did ask Tom Clark K3IO at the Orlando AMSAT convention this year about the exact topic you gentlemen are discussing. His comment was that there was only the Scud Rule to deal with. Norm n3ykf ___ time-nuts mailing 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 noise power supplies?
Ok, but open loop as I described? I bicmos design, there are two common junk buffers. The junkiest (sp?) is going up a PNP and down a NPN. No feedback. You live with the vbe mismatch. Next up the food chain is the long tail pair (diff amp) with emitter follower. With one gain stage, it is reasonable stable. -Original Message- From: John Miles jmi...@pop.net Sender: time-nuts-boun...@febo.com Date: Fri, 1 Feb 2013 01:30:24 To: 'Discussion of precise time and frequency measurement'time-nuts@febo.com Reply-To: Discussion of precise time and frequency measurement time-nuts@febo.com Subject: Re: [time-nuts] Low noise power supplies? Are 4 and 5 regulated? Or is the zener picked to compensate for the VBE drops? Any of these circuits where the output transistor is in an emitter follower configuration will have its noise effected by the load current, since that current directly effects the output transistor transconductance. The load in all cases was a couple hundred mA worth of resistance at the voltage in question, as I recall. It's been a few years since I captured these plots. The Zeners were just whatever parts came to hand, 1N474x parts basically. I didn't care about the 1.4V drop across the Darlington, just the resulting noise. -- john Miles Design LLC ___ time-nuts mailing 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] Loran again
Hello to the group. There is no need for slaves. Quite a while ago there was a slave but it was simply the master faking out a slaves position by delay. That said yes indeed the systems settling in well to the RB ref and I will switch over to the 3801 sometime this afternoon. Fired up the Austron 2100s Regards Paul WB8TSL On Fri, Feb 1, 2013 at 8:54 AM, Stan, W1LE stanw...@verizon.net wrote: Still locked onto the Dana/Seneca Loran stations at 8:38 am local. Comparison to GPS/DO is about the same. No new slaves detected. Stan, W1LECape Cod On 2/1/2013 12:30 AM, Stan, W1LE wrote: Fired up the SRS FS700 and auto found the GRI 89700 microsecond stations in Dana Il (master) and Seneca NY, (slave) both with equal signal strength of 63 db. Other slaves were not to be found. Noise margin of 32 dB and Rx gain of 72dB. So the Rx is all locked up. Tomorrow I will have more data comparing the 10 MHz from the T'Bolt. Right now they are comparing to within 10EE10. Stan, W1LE Cape Cod On 1/31/2013 10:44 PM, Stan, W1LE wrote: What GRI should we be listening for ? Stan, W1LECape Cod FN41sr On 1/31/2013 9:56 PM, paul swed wrote: Rich indeed its on the air. Warming up the FS700 to see if it will lock. Have a pattern ram thats getting flakey and takes about 30 minutes to warm up along with the oven. __**_ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/** mailman/listinfo/time-nutshttps://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-nutshttps://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-nutshttps://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] question for expert time guys
On 2/1/2013 3:45 AM, Hal Murray wrote: rickhar...@gmail.com said: I would like to triangulate a position of a device which moves using 3 fixed positions devices of known location. The idea is to have these operate on 915mhz or 434mhz or 2.4ghz or appropriate frequency. I'd like a range of 150 feet or better and accuracy of 3 feet or better. Doing this on radio will be tough. You are likely to need on the order of 10 or 20 MHz of ranging bandwidth to get the accuracy you want. This is also overkill in the extreme. For this range an line of sight I'd do it acoustically. Get some piezoceramic transducers and do it at 40 KHz or so. Transducers are ~$6 in single quantities. http://www.mouser.com/ds/2/209/KT-400482-193462.pdf Time of flight is about 13.5 inches per *milli* second, so your microprocessor will have time to do it's nails after processing ranging data. You should also get good accuracy and resolution. In general you shouldn't need to if you are using active transmitters at both ends, but if you are worried about multipath reflection use a PN code and use the first correlation peak. Rich -- mailto:o...@ozindfw.net Oz, N1OZ POB 93167 Southlake, TX 76092 (Near DFW Airport) ___ time-nuts mailing 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] Loran again
Anyone locking on Wildwood, NJ - they are still fired up. Bill, WA2DVU Cape May 89700 dana and the srs700 has been locked for 10 hours plus. Looking pretty good comparing RB adjusted to gps and 20ns drift will be at least 42 minutes. But just relooked at the drift and it may be much longer. SN in Boston 49db gain 33db margin. HP 3801 is warming up for a direct comparison. Regards Paul WB8TSL ___ time-nuts mailing 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] Loran again
Yes indeed I can see the local RB and GPS along with the eLORAN all starting to track and the local offsets are steadily decreasing. Great to see. SURE as heck beats the ole WWVB. Will guess long about 5pm local eLORAN will drop for the weekend. It needs a beer. Paul On Fri, Feb 1, 2013 at 11:09 AM, paul swed paulsw...@gmail.com wrote: Hello to the group. There is no need for slaves. Quite a while ago there was a slave but it was simply the master faking out a slaves position by delay. That said yes indeed the systems settling in well to the RB ref and I will switch over to the 3801 sometime this afternoon. Fired up the Austron 2100s Regards Paul WB8TSL On Fri, Feb 1, 2013 at 8:54 AM, Stan, W1LE stanw...@verizon.net wrote: Still locked onto the Dana/Seneca Loran stations at 8:38 am local. Comparison to GPS/DO is about the same. No new slaves detected. Stan, W1LECape Cod On 2/1/2013 12:30 AM, Stan, W1LE wrote: Fired up the SRS FS700 and auto found the GRI 89700 microsecond stations in Dana Il (master) and Seneca NY, (slave) both with equal signal strength of 63 db. Other slaves were not to be found. Noise margin of 32 dB and Rx gain of 72dB. So the Rx is all locked up. Tomorrow I will have more data comparing the 10 MHz from the T'Bolt. Right now they are comparing to within 10EE10. Stan, W1LE Cape Cod On 1/31/2013 10:44 PM, Stan, W1LE wrote: What GRI should we be listening for ? Stan, W1LECape Cod FN41sr On 1/31/2013 9:56 PM, paul swed wrote: Rich indeed its on the air. Warming up the FS700 to see if it will lock. Have a pattern ram thats getting flakey and takes about 30 minutes to warm up along with the oven. __**_ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/** mailman/listinfo/time-nutshttps://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-nutshttps://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-nutshttps://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] Loran again
See my comment above On Fri, Feb 1, 2013 at 11:23 AM, Bill Riches bill.ric...@verizon.netwrote: Anyone locking on Wildwood, NJ - they are still fired up. Bill, WA2DVU Cape May 89700 dana and the srs700 has been locked for 10 hours plus. Looking pretty good comparing RB adjusted to gps and 20ns drift will be at least 42 minutes. But just relooked at the drift and it may be much longer. SN in Boston 49db gain 33db margin. HP 3801 is warming up for a direct comparison. Regards Paul WB8TSL ___ time-nuts mailing 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] Loran again
By the way I am calling it eLORAN but I think UrsaNav has another name for it. Regards Paul On Fri, Feb 1, 2013 at 11:28 AM, paul swed paulsw...@gmail.com wrote: See my comment above On Fri, Feb 1, 2013 at 11:23 AM, Bill Riches bill.ric...@verizon.netwrote: Anyone locking on Wildwood, NJ - they are still fired up. Bill, WA2DVU Cape May 89700 dana and the srs700 has been locked for 10 hours plus. Looking pretty good comparing RB adjusted to gps and 20ns drift will be at least 42 minutes. But just relooked at the drift and it may be much longer. SN in Boston 49db gain 33db margin. HP 3801 is warming up for a direct comparison. Regards Paul WB8TSL ___ time-nuts mailing 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 noise power supplies?
Content-Type: text/plain; charset=ISO-8859-1 In message 2bf4f4e8c8207ae0f94a7e1a1e63c...@quipo.it, Fabio Eboli writes: Il 2013-01-31 06:42 Mark Sims ha scritto: A123 20Ah LiFePO4 cells have an internal resistance in the milliohm range. [...] Low internal resistance in batteries is an indicator of low noise, but not a guarantee of low noise. For instance in wet lead-acid cells, turbulence in the liquid as the density changes can lead to low-frequency noise, which incidentally sounds a lot like a pot of stew simmering. -- 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.
Re: [time-nuts] question for expert time guys (Hal Murray)
Hello Hal - I spent a lot of my RF engineering career in related areas, including radar, EW, and spread spectrum timing systems. Since the distance is short and the cost is an issue you may wish to consider an analog system solution. Specifically your master station transmits a RF signal that is FM modulated with a high frequency tone. The remote unit is a transponder. It receives the tone and re-transmits back on another frequency. Almost no parts required. At the master station the phases of the outgoing and returning tones are compared. The distance is directly proportional to the phase shift between the outgoing and incoming tones. For instance if the tone is 10 MHz the 360 degrees of phase is 100 nS which is about 100 ft round trip. The phase may be measured either analog and A/D converted or digitally and in either case is then easily converted to range by your processor. By adjusting the tone frequency you can set the full scale range. To increase resolution higher frequency tones may be used. To overcome ambiguity when the range goes beyond 360 degrees of phase, add a lower frequency tone to resolve the ambiguity. This scheme has been used in surveying instruments (the Teleurometer) and even an ill fated German bombing system in WWI. The latter proved delightfully easy to jam since the Brits had a spare TV transmitter in the correct band. Look up something like tone ranging. -john c roos k6iql -Original Message- From: time-nuts-request time-nuts-requ...@febo.com To: time-nuts time-nuts@febo.com Sent: Fri, Feb 1, 2013 4:24 am Subject: time-nuts Digest, Vol 103, Issue 2 Send time-nuts mailing list submissions to time-nuts@febo.com To subscribe or unsubscribe via the World Wide Web, visit https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts or, via email, send a message with subject or body 'help' to time-nuts-requ...@febo.com You can reach the person managing the list at time-nuts-ow...@febo.com When replying, please edit your Subject line so it is more specific than Re: Contents of time-nuts digest... Today's Topics: 1. Re: Loran again (Stan, W1LE) 2. question for expert time guys (Rick Harold) 3. Re: Low noise power supplies? (gary) 4. Re: Low noise power supplies? (John Miles) 5. Re: question for expert time guys (Hal Murray) 6. Re: question for expert time guys (Azelio Boriani) -- Message: 1 Date: Fri, 01 Feb 2013 00:30:40 -0500 From: Stan, W1LE stanw...@verizon.net To: Discussion of precise time and frequency measurement time-nuts@febo.com Subject: Re: [time-nuts] Loran again Message-ID: 510b5300.8000...@verizon.net Content-Type: text/plain; charset=ISO-8859-1; format=flowed Fired up the SRS FS700 and auto found the GRI 89700 microsecond stations in Dana Il (master) and Seneca NY, (slave) both with equal signal strength of 63 db. Other slaves were not to be found. Noise margin of 32 dB and Rx gain of 72dB. So the Rx is all locked up. Tomorrow I will have more data comparing the 10 MHz from the T'Bolt. Right now they are comparing to within 10EE10. Stan, W1LE Cape Cod On 1/31/2013 10:44 PM, Stan, W1LE wrote: What GRI should we be listening for ? Stan, W1LECape Cod FN41sr On 1/31/2013 9:56 PM, paul swed wrote: Rich indeed its on the air. Warming up the FS700 to see if it will lock. Have a pattern ram thats getting flakey and takes about 30 minutes to warm up along with the oven. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. -- Message: 2 Date: Thu, 31 Jan 2013 22:37:00 -0600 From: Rick Harold rickhar...@gmail.com To: time-nuts@febo.com Subject: [time-nuts] question for expert time guys Message-ID: CAODR2TDuMSpOr8JYvjMm-QRnRhM8sxYGkY=vrn6yttk5t3t...@mail.gmail.com Content-Type: text/plain; charset=ISO-8859-1 To time experts/EE's. I would like to triangulate a position of a device which moves using 3 fixed positions devices of known location. The idea is to have these operate on 915mhz or 434mhz or 2.4ghz or appropriate frequency. These two type of devices (fixed and mobile) are all under my control and thus customized as needed. The mobile device (not a phone, custom device) would be the least expensive item. I'd like a range of 150 feet or better and accuracy of 3 feet or better. When manufactured these items they can be calibrated in order to adjust for any variation in IC's, discrete components etc... We can assume for now the temperature is constant 70 degree temperature. Cost is the key design factor. The general flow is: 1. base station 1 indicates we are determining position of device A. 2. Each base station 1, 2, 3 take turns pinging the device to determine distance.
Re: [time-nuts] Low noise power supplies?
Joe wrote: Back when I was in product engineering there was a VCO design that used a superfilter circuit. It consisted of a pass transistor and a filter cap from base to ground. The gain of the transistor multiplied the effective capacitance. I have not seen this configuration since. They are often called capacitance multipliers and are popular with (among others) audio designers as low-noise supplies for low-level circuits (moving coil head amps, RIAA stages, etc.). They are best used following an active regulator. If the capacitor is electrolytic, it needs to be chosen very carefully so that leakage current noise doesn't spoil the effort. Also, it is best to use a voltage divider on the base to give the transistor a bit of headroom (i.e., base voltage should be a volt or so lower than collector voltage, not the same as the collector voltage as happens when there is just a pull-up resistor on the base). Best regards, Charles ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] question for expert time guys (Hal Murray)
Hi To complete the thought: Three base stations on three different transmit frequencies over a 50 MHz range. Mobile has a local oscillator at say 200 MHz. Filter the incoming frequency range, stuff it into a mixer, filter the output. What's transmitted back gets processed at the base station. Yes you would have to be running at a high enough frequency to keep everything in an appropriate band. Bob -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of johncr...@aol.com Sent: Friday, February 01, 2013 12:16 PM To: time-nuts@febo.com Subject: Re: [time-nuts] question for expert time guys (Hal Murray) Hello Hal - I spent a lot of my RF engineering career in related areas, including radar, EW, and spread spectrum timing systems. Since the distance is short and the cost is an issue you may wish to consider an analog system solution. Specifically your master station transmits a RF signal that is FM modulated with a high frequency tone. The remote unit is a transponder. It receives the tone and re-transmits back on another frequency. Almost no parts required. At the master station the phases of the outgoing and returning tones are compared. The distance is directly proportional to the phase shift between the outgoing and incoming tones. For instance if the tone is 10 MHz the 360 degrees of phase is 100 nS which is about 100 ft round trip. The phase may be measured either analog and A/D converted or digitally and in either case is then easily converted to range by your processor. By adjusting the tone frequency you can set the full scale range. To increase resolution higher frequency tones may be used. To overcome ambiguity when the range goes beyond 360 degrees of phase, add a lower frequency tone to resolve the ambiguity. This scheme has been used in surveying instruments (the Teleurometer) and even an ill fated German bombing system in WWI. The latter proved delightfully easy to jam since the Brits had a spare TV transmitter in the correct band. Look up something like tone ranging. -john c roos k6iql ___ time-nuts mailing 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 noise power supplies?
Sorry, Poul-Henning Kamp, I answered directly to your mail address, I repost it here... Il 2013-02-01 18:09 Poul-Henning Kamp ha scritto: Content-Type: text/plain; charset=ISO-8859-1 In message 2bf4f4e8c8207ae0f94a7e1a1e63c...@quipo.it, Fabio Eboli writes: Il 2013-01-31 06:42 Mark Sims ha scritto: A123 20Ah LiFePO4 cells have an internal resistance in the milliohm range. [...] Low internal resistance in batteries is an indicator of low noise, but not a guarantee of low noise. I have no reason to disagree with your statement :) I was agreeing with Mark about the fact that there are new chemistries with low internal resistance, and nice characteristics like low cost, availability and low self discharge, and that some Li-ion can be built to be one of those. For instance in wet lead-acid cells, turbulence in the liquid as the density changes can lead to low-frequency noise, which incidentally sounds a lot like a pot of stew simmering. It would be interesting to see if there are references about noise in the li chemistries. Fabio. ___ time-nuts mailing 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 noise power supplies?
Well, I stand corrected. Weren't the TM 500 instruments marketed as low cost? Regards. Max. K 4 O DS. Email: m...@maxsmusicplace.com Transistor site http://www.funwithtransistors.net Vacuum tube site: http://www.funwithtubes.net Woodworking site http://www.angelfire.com/electronic/funwithtubes/Woodworking/wwindex.html Music site: http://www.maxsmusicplace.com To subscribe to the fun with transistors group send an email to. funwithtransistors-subscr...@yahoogroups.com To subscribe to the fun with tubes group send an email to, funwithtubes-subscr...@yahoogroups.com To subscribe to the fun with wood group send a blank email to funwithwood-subscr...@yahoogroups.com - Original Message - From: David davidwh...@gmail.com To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Thursday, January 31, 2013 11:10 PM Subject: Re: [time-nuts] Low noise power supplies? I have seen it used in a couple of Tektronix TM500 instruments but the purpose may have been to generate a lower voltage power supply rail instead of noise reduction. Tektronix often added LC sections on their switching power supply outputs and distributed smaller LC sections to prevent coupling between different circuits. On Thu, 31 Jan 2013 22:12:42 -0600, Max Robinson m...@maxsmusicplace.com wrote: You haven't seen it used because it doesn't work very well. It appeared in a few pieces of Heathkit equipment but I don't think HP or Tek used it at all. Any AC component of base to collector voltage has a small but definite effect on Vbe which transfers voltage in the reverse direction from collector to emitter even though the base is held at AC ground. A three terminal regulator does a better job of suppressing ripple from a power supply. Regulators use a zener diode as the reference and there are circuits in which a zener is used as a noise source. What does that tell you? The quietest power supply is an analog regulator followed by one or more RC filter sections. The inductor in an LC filter is likely to pick up more hum and noise than it filters out. My presumption is that a low noise power supply is likely to be providing a small amount of power to the load and load regulation is probably not a problem. ___ time-nuts mailing 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 noise power supplies?
This is a keeper. Note the strong peak at 60 Hz for the unfiltered darlington. Regards. Max. K 4 O DS. Email: m...@maxsmusicplace.com Transistor site http://www.funwithtransistors.net Vacuum tube site: http://www.funwithtubes.net Woodworking site http://www.angelfire.com/electronic/funwithtubes/Woodworking/wwindex.html Music site: http://www.maxsmusicplace.com To subscribe to the fun with transistors group send an email to. funwithtransistors-subscr...@yahoogroups.com To subscribe to the fun with tubes group send an email to, funwithtubes-subscr...@yahoogroups.com To subscribe to the fun with wood group send a blank email to funwithwood-subscr...@yahoogroups.com - Original Message - From: John Miles jmi...@pop.net To: 'Discussion of precise time and frequency measurement' time-nuts@febo.com Sent: Friday, February 01, 2013 12:03 AM Subject: Re: [time-nuts] Low noise power supplies? Awhile back I ran some baseband plots of various supplies with an HP 3048A (image attached). In my experience measuring actual OCXOs, an LM317T or LM338K is quiet enough to avoid influencing oscillator PN. With these variable-voltage parts, you can bypass the reference pin for some additional improvement, but I don't believe I did that for these plots. It's easy to spot the difference between a 7812/7815 and an LM317T (see red versus green/white traces). As a lazy approach, try measuring the oscillator with both a 78XX and an LM317T. Because the 78XX is about 10 dB noisier across most of the spectrum, If you don't see a difference, you can assume that further optimization is pointless. Near 1 Hz this call may be questionable. If you don't need an LDO, don't use one. If you do, use the quietest part you can find. The best LDOs seem to be about as quiet as an ordinary LM317T. I've mentioned before that you need to be careful with large LC filters downstream of the regulator. A good power source will exhibit a low impedance at ALL offsets of interest. You sometimes see NIST circuits where the power is conditioned by a Darlington emitter follower whose base is fed with an RC-filtered Zener diode. The purple and orange traces are pretty informative with regard to that approach. On the orange trace, where the only filtering is the RC network between the Zener and the base, notice how the noise becomes worse than all of the other sources below 10 Hz. Here, the RC filter on the Zener becomes less effective and the Darlington pair obligingly amplifies the diode noise. An additional LC filter after the regulator may have the effect of herding the entire noise spectrum into a high-Q peak, even though the LC corner frequency is much higher than the RC filter in the base circuit (violet trace). Depending on your OCXO's supply rejection characteristics this could be a good thing or a bad thing. Finally, make sure the OCXO has good RF bypassing where its power supply pin enters the case. If in doubt, solder a 0.1 uF ceramic right at the point of entry. I've seen $2000 Wenzels that didn't bother doing this. I'm sure they looked good in a screen room. -- john Miles Design LLC -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts- boun...@febo.com] On Behalf Of Richard (Rick) Karlquist Sent: Wednesday, January 30, 2013 6:17 PM To: Discussion of precise time and frequency measurement Subject: [time-nuts] Low noise power supplies? I know this topic has been discussed in the past on the list, but a colleague is asking if there are any off the shelf low noise power supplies for testing oscillators. Something a cut above an HP brick lab power supply etc. They are hoping to avoid having to homebrew a power conditioning circuit. Did we ever arrive at a concensus as to the state of the art in homebrew power conditioning circuits? Any help would be appreciated. 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. ___ time-nuts mailing 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 noise power supplies?
Well the Tek current probe that goes in the power supply wasn't low cost. They also had a nice bench supply that went in the box. But a lot of the instruments weren't so fancy. -Original Message- From: Max Robinson m...@maxsmusicplace.com Sender: time-nuts-boun...@febo.com Date: Fri, 1 Feb 2013 13:39:14 To: Discussion of precise time and frequency measurementtime-nuts@febo.com Reply-To: Discussion of precise time and frequency measurement time-nuts@febo.com Subject: Re: [time-nuts] Low noise power supplies? Well, I stand corrected. Weren't the TM 500 instruments marketed as low cost? Regards. Max. K 4 O DS. Email: m...@maxsmusicplace.com Transistor site http://www.funwithtransistors.net Vacuum tube site: http://www.funwithtubes.net Woodworking site http://www.angelfire.com/electronic/funwithtubes/Woodworking/wwindex.html Music site: http://www.maxsmusicplace.com To subscribe to the fun with transistors group send an email to. funwithtransistors-subscr...@yahoogroups.com To subscribe to the fun with tubes group send an email to, funwithtubes-subscr...@yahoogroups.com To subscribe to the fun with wood group send a blank email to funwithwood-subscr...@yahoogroups.com - Original Message - From: David davidwh...@gmail.com To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Thursday, January 31, 2013 11:10 PM Subject: Re: [time-nuts] Low noise power supplies? I have seen it used in a couple of Tektronix TM500 instruments but the purpose may have been to generate a lower voltage power supply rail instead of noise reduction. Tektronix often added LC sections on their switching power supply outputs and distributed smaller LC sections to prevent coupling between different circuits. On Thu, 31 Jan 2013 22:12:42 -0600, Max Robinson m...@maxsmusicplace.com wrote: You haven't seen it used because it doesn't work very well. It appeared in a few pieces of Heathkit equipment but I don't think HP or Tek used it at all. Any AC component of base to collector voltage has a small but definite effect on Vbe which transfers voltage in the reverse direction from collector to emitter even though the base is held at AC ground. A three terminal regulator does a better job of suppressing ripple from a power supply. Regulators use a zener diode as the reference and there are circuits in which a zener is used as a noise source. What does that tell you? The quietest power supply is an analog regulator followed by one or more RC filter sections. The inductor in an LC filter is likely to pick up more hum and noise than it filters out. My presumption is that a low noise power supply is likely to be providing a small amount of power to the load and load regulation is probably not a problem. ___ time-nuts mailing 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] Loran again
OK beer time came early eLORAN is off the air at 2000 UTC On Fri, Feb 1, 2013 at 11:30 AM, paul swed paulsw...@gmail.com wrote: By the way I am calling it eLORAN but I think UrsaNav has another name for it. Regards Paul On Fri, Feb 1, 2013 at 11:28 AM, paul swed paulsw...@gmail.com wrote: See my comment above On Fri, Feb 1, 2013 at 11:23 AM, Bill Riches bill.ric...@verizon.netwrote: Anyone locking on Wildwood, NJ - they are still fired up. Bill, WA2DVU Cape May 89700 dana and the srs700 has been locked for 10 hours plus. Looking pretty good comparing RB adjusted to gps and 20ns drift will be at least 42 minutes. But just relooked at the drift and it may be much longer. SN in Boston 49db gain 33db margin. HP 3801 is warming up for a direct comparison. Regards Paul WB8TSL ___ time-nuts mailing 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.
