Re: [time-nuts] Symmetricom 5115
Dear Nicholas, Thank you for getting this discussion back to technical aspects related our real quest for technical information. Please look in your actual documentation for the current model 5125 and confirm its actual specs. I had read some specs on the Symmetricom website but I do not know for which model. Although automated and easy to use, I remember that the phase noise floor was lackluster and makes me think that this may be fine for very close-in measurments but not for the usual 100Hz to 100KHz offset measurments. Please let us know what you find with this equipment. Regards, Jeffrey Pawlan ___ time-nuts mailing 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] Missing GPS satellites
On Thu, 25 Mar 2010, Magnus Danielson wrote: Dear Raj, Oh, sorry, needed a few extra. Wanted to recover the rubidiums and put some on Ebay. I gave a lecture about antennas for operation on 1296MHz last week and mentioned that my vacuum tube power abplifier was damaged by a gassy tube. I want to replace it with a solid state amp. One of the engineers present suggested that I find a GPS satellite on the surplus market and pull the the power amplifier out of it. He obviously did not know that satellites , even spares, do not show up on the surplus market. ___ time-nuts mailing 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] AMC-123 patent (was: Re: Phase Noise of 74AC gates)
That is the first Norton patent. The later one was co-authored by Allen Podell and uses a single transformer with three windings. I wrote a series of two articles on the SPICE and also Serenade simulation of a real constructed amplifier using the circuit in the second patent. The match, IP3, and NF are very good, both the reverse isolation is poor. Regards, Jeffrey Pawlan ___ time-nuts mailing 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 - RF Mailing list
The 50MHz and Up Group of N. Calif primarily has members who really prefer 900MHz and up. When I first formed it, I did invite speakers about 6m and 2m DXing however, since then there has not been much interest in those low frequencies. However, anyone is definitely welocme to join as either a member or an out-of-the-area friend. There are no dues this year for members. Rick - fill out the memberform 73, Jeffrey Pawlan WA6KBL ___ time-nuts mailing 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] 60Hz mains clocking in computers
Dear Jim, Another overlap in our past. Back when I was at UCLA I helped the Ethnomusicology dept with their filming along with synced sound. This was in 1963-64. I designed and built a crystal sync system using the newly available RTL logic ICs. I then modified a 16mm Arri to use it to precisely drive the DC motor because the Arri of course had a 60Hz sync generator built in that would be fed to the Nagra for sound. I phase locked the 60Hz to the divided down discrete 10MHz crystal oscillator I built and thus controlled the speed of the DC motor. It worked very well. The precise 60Hz could be directly sent to the Nagra for the sync track or a separate identical crystal controlled 60Hz source could be right at the Nagra. I took this to the business offices of Eclair in Hollywood and tried to get them to buy or license my idea. They told me that this precision was unnecessary. I was young and not business savy so I did not know to have them sign a non-disclosure. The next year, they came out with exactly what I had showed them. Best Regards, Jeffrey Pawlan ___ time-nuts mailing 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] acctime2000,symmetricom/Hp 58534 connector source
On Sun, 6 Dec 2009, Stanley Reynolds wrote: Newark has Farnell components IMC26-2212X which fit. SKU 93K6411 Price: $6.94 pins and hood are ordered separate Stanley watch out for Newark's shipping and Handling charge. I had ordered a connector from them several years ago and was upset when I received the invoice after my credit card had been charged. They had added a large extra charge that they had not mentioned on the phone at the time of the order. ___ time-nuts mailing 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] acctime2000,symmetricom/Hp 58534 connector source
Thank you for the update. My order was over $50 but perhaps since then they got too many compaints and decided to change their policy. ___ time-nuts mailing 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] PC time
On Wed, 25 Nov 2009, Bob Camp wrote: Hi Doesn't everybody run OCXO's for the clock in their PC? Bob you should make one of those text displays on the bottom of your email that reads: my PC clock is controlled by an HP10811 That distinguishes Time-Nuts members from the general public. ___ time-nuts mailing 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] Calculating frequency differences using Lissajou figures
or stated in another way: your two sources differ by 5.5 parts in 10^-10 Well within the specification for the Rb. But to be precise, but if you wanted to know the absolute accuracy of the Rb then you would need to know the accuracy of the GPSDO at that moment in time. Jeffrey Pawlan ___ time-nuts mailing 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] WWV Clock
My clock changed. I am in Calif. 73, Jeffrey Pawlan WA6KBL ___ time-nuts mailing 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] Fundamental limits on performance
This is the specialization of Judah Levine at NIST. 73, Jeffrey Pawlan ___ time-nuts mailing 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] Have Austron 2110 manual, looking for Datum 2110C manual
Tom and John, I am still using my Austron loran c receiver with an austron 2110 disciplined frequency standard. I have made several modifications as well as repairs to both units. I purchased the manual from Austron when they were still in business. I think it was around $125. I looked at the titlepage and it is revision L and was from Sept 1988. I do not know whether Datum revised it after that. Regards, Jeffrey Pawlan Pawlan Communications ___ time-nuts mailing 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] Sound Cards for locking to GPSDO 10 MHz references
Soundcards for USB are poor at best. I have a set of PCI cards that were previously made by EMU and they accept external reference input. They no longer make the model I have but perhaps they have another PCI card with an external ref input. I am interested in your modulation technique which allows you to use WSJT. Please let me know exactly what you are doing. I also do not know how you are using 5 milliHertz with WSJT since the group of discrete tones occupy more bandwidth. 73, Jeffrey Pawlan WA6KBL ___ time-nuts mailing 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] Ultra low noise Pierce oscillator???
My best crystal oscillator designs are modified Pierce. But I definitely recommend using a low noise BJT else you will have 1/f noise. Jeffrey Pawlan WA6KBL Pawlan Communications ___ time-nuts mailing 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] Enrico Rubiola's new book
I had hoped to meet him at the UFFC last Spring but he cancelled at the last moment owing to a family emergency. Take a look at his webpage: http://www.femto-st.fr/~rubiola/ Jeffrey Pawlan WA6KBL sr member IEEE UFFS MTT ___ time-nuts mailing 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] ADEV secondary standard
You have just described the current preferred method used by NIST for calibrating phase noise measurements. ___ time-nuts mailing 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] ADEV secondary standard
The only difficulty at all is simply the instrument calibration. One must have true knowledge about the noise bandwidth of the filter (usually a window) being measured. I do know that HP, NIST, and I have used simple CW carriers instead of noise for the calibration. This is a good method for one offset frequency. In fact, it is slighty more dependable and accurate being a single tone. Its only disadvantage is that one needs to repeat this at every offset you want to calibrate so that is why the noise method was invented. Jeffrey Pawlan ___ time-nuts mailing 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] Checking accuracy of Rubidium standards
On Sat, 8 Nov 2008, Randy wrote: I was wondering if it is worthwhile or even feasible to compare an LPRO Rubidium standard against a Z3801. Since their frequencies are probably going to be extremely close anyway it would seem some special method/equipment would be required for high precision. Suggestions? Randy, W7HR Port Orchard, WA The best way would be to compare the highest possible frequencies you can generate with these two sources. I use two 10GHz sources that are each phase locked to an external 10MHz reference. Then the 10GHz outputs can be compared using either of these easy methods: 1) look at the DC/IF output of a microwave mixer where the LO and RF ports are driven by the two 10GHz sources. Don't overdrive the RF input to a level that can burn out your mixer. 2) use a good microwave frequency counter to read one of the 10GHz outputs while driving the counter's 10MHz ext ref input with the 10MHz from the other 10MHz source. This is very fast but will only give you accuracy readings that are a function of the resolution of the counter plus the bounce of the last digit owing to sampling and triggering. 3) if you have access to a lab with one or two microwave synthesized signal generators, then you can apply the 10MHz sources to the ext ref inputs of each of these signal generators and then proceed as in 1) or 2) I have done comparison at 26GHz this way so I have a bit more resolution. 73, Jeffrey Pawlan WA6KBL ___ time-nuts mailing 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] Checking accuracy of Rubidium standards
Dear Dave, I was fortunate to find two surplus brick PLOs that had 10MHz input. But I also have synthesized microwave signal generators with ext ref inputs and an EIP 575 with ext ref input. Perhaps there is a commercial lab or engineering school where you can use equipment like this and do the experiments. Otherwise, beating two 10MHz sources together will require a strip chart recorder so you can see the long term trends over days as indicated by someone else who responded. The methods I use do not take into account long term drift but are simply meant to be measurements that can display 1E-9 or 1E-10 in just one second of your time. To get finer than that, you patiently wait. 73, Jeffrey Pawlan WA6KBL ___ time-nuts mailing 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- RK devices?
They were a competitor to minicircuits and others. Tried to win by being very inexpensive. ___ time-nuts mailing 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 monitor
Regarding the VFD display, although they may be very different one manufacturer to another, I can definitely dispute a prior statement made that VFDs in general have a short lifetime and become dim. They are universally used in VCRs, DVD players, microwave ovens, and some clocks. I have never had one become dim or burn out. The displays in my appliances are on even when the rest of the appliance is off. I have never seen one become dim even after 15 years of on-time. I look forward to your project. 73, Jeffrey Pawlan, WA6KBL ___ time-nuts mailing 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] 20logN was Re: phase noise questions
On Sat, 26 Jan 2008, Bruce Griffiths wrote: The following paper on the symmetry and correlation between the USB and LSB components of PM and AM may be of interest: http://tf.nist.gov/timefreq/general/pdf/1326.pdf Where among other results it is shown that a phase detector has the same response to coherent PM sidebands and PM noise sidebands. Bruce As seen in the acknowledgements, it was I who initially proposed this idea to Fred Walls. We exchanged letters and phone calls then I visited him in Boulder to discuss the measurements. Jeffrey Pawlan ___ time-nuts mailing 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] answers
I was thinking of both the opamp and expecially the internal reference's noise but I did not express it well. The rest does not need any further discussion, especially since this has degraded to one-upsmanship and insults. re my computer and unix, I have replied off list as this is not relevant to time-nuts. Regards, Jeffrey Pawlan ___ time-nuts mailing 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] ** SPAM ** Re: Bruce's link
On Fri, 14 Dec 2007, Bruce Griffiths wrote: One of the better sites with info on such regulators is: http://sjostromaudio.com/joomla/index.php?option=com_contenttask=viewid=26Itemid=27 http://sjostromaudio.com/joomla/index.php?option=com_contenttask=viewid=26Itemid=27 1. This is an unnecessarily complex design. You can achieve the same performance by cascading the normal regular with an integrated low noise regulator. I prefer Linear Technology ICs for this. 2. Bruce and others, you should really check your links before posting them. On this page was a link to get the full PDF of the schematic. When you click on that, you get a 404 not found plus you get a popup ad. Worse still, if you click on the schematic to enlarge it, instead of getting the schematic you get a full page PORN ad. 73, Jeffrey Pawlan WA6KBL Pawlan Communications Spam detection software, running on the system jeffrey150.pawlan.com, has identified this incoming email as possible spam. The original message has been attached to this so you can view it (if it isn't spam) or label similar future email. If you have any questions, see [EMAIL PROTECTED] for details. Content preview: On Fri, 14 Dec 2007, Bruce Griffiths wrote: One of the better sites with info on such regulators is: http://sjostromaudio.com/joomla/index.php?option=com_contenttask=viewid=26Itemid=27 http://sjostromaudio.com/joomla/index.php?option=com_contenttask=viewid=26Itemid=27 [...] Content analysis details: (13.6 points, 5.0 required) pts rule name description -- -- -1.4 ALL_TRUSTEDPassed through trusted hosts only via SMTP 15 JP_PORNBODY: BODY: porn ___ time-nuts mailing 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] re low noise regulators
I checked both datasheets, the 723 and the LT1762. It was specsmanship that rated the 723 as having lower noise. Here's how: The internal comparison opamp in the 723 was OK for its day back in Fairchild's history but by today's standards, it is noisy and has poor gain and BW. So in order to make the regulator low noise, a 5uF capacitor had to be placed across the ref comparison input. The low noise, and even the standard linear regulators today are much quieter and few people need 5uV of power supply noise, especially given that the circuitry we place on the power rails will almost certainly spoil that. So no one specs putting a 5uF cap on the ref line. The LTC LT1762 does suggest a Cbyp of .01uF will provide a noise of 20uV broad bandwidth as you correctly stated. I am certain that putting a higher value cap and perhaps even a RC filter on the reference input will lower this substantially. But again, I suggest that it will become meaningless to all but Super-Audio Snake Oil people because any circuitry powered from the produced Vcc line will add more noise than the regulator. Even with the now ancient history LM317 style adjustables, I always put a tantalum cap across the reference to ground. It does wonders for getting rid of traces of hum. Just for your collection I will send John two App notes in PDF form to post. They cover the subject of reducing spikes and switching regulator noise. regards and 73, Jeffrey Pawlan WA6KBL Pawlan Communications ___ time-nuts mailing 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: Prologix GPIB and HP3478A...
On Tue, 27 Nov 2007, Prologix wrote: Hello Chuck, It appears that 3478A sends data continuously as soon as it is addressed to talk. Since the Prologix adapter is busy processing GPIB data it is unable to respond to USB commands. One solution is to turn read-after-write off (++auto 0) before connecting the adapter to 3478A, and then use ++read command to read one measurement at a time. Please see the manual (www.prologix.biz) for ++read command options. The other option is to set 3478A to one-reading-per-trigger mode using T3 device command. See HP3478 manual (pages 39, 59). Then use the ++trg command to trigger the device. ++auto must be set to 1 in this case. Regards, Abdul Excellent answer! I do not have either piece of equipment but I can certainly say that even though I am now using NI GPIB cards which are likely faster, I always program the instrument being queried to only send one response per trigger. I learned BASIC and also HPIB programming on a HP85 when it was the latest and greatest in 1980-81. Then later in another company I used the 9845 and then after that used the 9836. I think I must have learned from their wonderful documentation sets that this was the right way to take readings. It may well have been to avoid the timing issues you presented. Regards, Jeffrey Pawlan ___ time-nuts mailing 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 scan.
); SAEximRunCond expanded to false Errors-To: [EMAIL PROTECTED] RETRY Yes, I will do that. 73, Jeffrey Pawlan WA6KBL ___ time-nuts mailing 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: Need HP 7475A Drivers manuals
); SAEximRunCond expanded to false Errors-To: [EMAIL PROTECTED] RETRY I have the ORIGINAL HP7475 Graphics Plotter SERVICE MANUAL dated June 1990. It has complete schematics, disassembly, adjustments, parts lists. I also have a rather extensive supply of new HP short pen style plotter pens and refillable accessories, a list 26 items long. Anyone interested? I would rather sell them to friends here than on ebay. 73, Jeffrey Pawlan WA6KBL ___ time-nuts mailing 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 with LPRO 101
); SAEximRunCond expanded to false Errors-To: [EMAIL PROTECTED] RETRY Easier way to read those last digits is to use a synthesized 20GHz or higher synthesizer and a counter that can read this to 1Hz. Then lock one to one source and the other to the other source. Parts in 1E-10 now readable in a second. 73, Jeffrey Pawlan WA6KBL ___ time-nuts mailing 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] Crystal Ageing
); SAEximRunCond expanded to false Errors-To: [EMAIL PROTECTED] RETRY It was Rick who wrote about crystal aging. It is not predictable whether the crystal will go higher or go lower in frequency and there is no guarantee that it will age at a linear rate. The worst-case is when a crystal erratically jumps. I had attended a conference of the Frequency Control Symposium of the IEEE in which the causes were discussed. There was disagreement among the experts. Some thought it was owing to the physical stress or surface imperfections caused by grinding and lapping. Others thought it may be partially a result of the etching. Others thought it was caused by microscopic impurities in the quartz. Others talked about the effects of plating. Rick wrote about the microcrystalline structural defects. Perhaps all of these contribute and it is unpredictable how they will add together. 73, Jeffrey Pawlan WA6KBL ___ time-nuts mailing 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] TV sync
Hi Tom, a related very interesting experiment is to take the Horizontal Sync signal from an old Tube-type TV, and feed it to a frequency counter with GPSDO time base (preferrably). Got to be careful about the high voltages inside the TV though! BTW: it's not 15374KHz, there are some significant decimal digits (I don't recall the formula to calculate the frequency exactly, but it was the total number of frame lines multiplied by 59.94Hz or so). Then you can test how accurate the broadcasters' 27MHz reference clock is. One would be surprised how inaccurate(!) some broadcasters are, and how much drift some Satellite providers have. A lot of the stability is dependent on the receiver of course, and how well the receiver's VCXO locks to the Broadcaster. bye, Said wrong All larger TV stations use Cs standards. What you don't know is that the FCC assigns SLIGHTLY different scan frequencies to each station on the same channel in a close area so when you are in a fringe area between two stations on the same channel, you will intentionally see both pictures superimposed with a rolling of the scan lines. Otherwise they would be locked and you would see only black and white bars. Satellite broadcasts are completely different and I do not know the FCC specification for those. ___ time-nuts mailing 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] from Sputnik to CD
); SAEximRunCond expanded to false Errors-To: [EMAIL PROTECTED] RETRY You are not off base. I know the inventor of the high definition CD standard and he has the patents on the mastering system. He had made for his company a special piece of test equipment to measure picosecond jitter. I questioned whether the ear could hear jitter that fine but he insisted it was the key to good A/D and D/A. Those were also custom made for them and in use are mounted on a precision temperature controlled base because their accuracy is really good at only one temperature. The actual frequency was not critical hence a double oven crystal was not necessary. Regards, Jeffrey Pawlan ___ time-nuts mailing 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] from Sputnik to CD
); SAEximRunCond expanded to false Errors-To: [EMAIL PROTECTED] RETRY You are way incorrect in your reply. Since this is off-topic I will limit my reply to a few salient points. High definition CD is not at 44.1KHz It is much higher so your ratio is off. The A/D and D/A converters they use are TESTED at better than 125dB spurious free dynamic range and they are for studios not home use. He also was the designer and has the patents on loudspeakers that have active servo feedback of the voice coil position and he does design for current drive rather than voltage drive. enough said on this. ___ time-nuts mailing 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] update on SARSAT and Galileo
); SAEximRunCond expanded to false Errors-To: [EMAIL PROTECTED] RETRY The current issue of Inside GNSS has a final update on Galileo and GPS bandplans and the coding for each signal. Galileo will carry the new SARSAT, receiving from 406 to 406.1MHz then broadcasting these signals on sub-carriers of downlinks from 1544 to 1545MHz. Unfortunately, it was announced that Galileo will transmit multiple modulations plus pilot tomes in the amateur radio band at 1278.75MHz. This will not likely affect terrestrial amateur radio communications but it would definitely affect very weak signal Earth-Moon-Earth communications which are always done from 1296 - 1297MHz and our antennas are pointed at the moon but the antenna beamwidth is usually 10 - 20 degrees wide. Jeffrey Pawlan ___ time-nuts mailing 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] Sputnik
); SAEximRunCond expanded to false Errors-To: [EMAIL PROTECTED] RETRY On Thu, 4 Oct 2007, Brooke Clarke wrote: It's interesting to tracing the path from the doppler data which was used to determine the slant range between he satellite and the receiver antenna. Some cleaver thinking then leads to the idea that you can determine were you are if you know the satellite orbital parameters. Dear Brooke and friends, You have described the actual method of position determination for the COSPAS/SARSAT search and rescue system. The original ELTs (emergency location beacon transmitters) on 121.5, 243, and around 403MHz were in use on ships, lifeboats, and airplanes long before GPS. So they basically only could transmit a modulated carrier. How to find the location of a distress signal before you can send out aircraft to fly over the area? You put up a number of NON-stationary satellites that all receive these frequencies then convert their doppler shift to sub-carriers on a microwave transmitter that is downlinked to coast guard stations all over the world. These have a tracking system and also a dedicated special purpose computer that calculates the location of the ELT from the orbital information of the satellite that received the signal and the doppler shift of the VHF or UHF signal from the ELT. Then planes and resue ships are dispatched. This program was a cooperative effort of the US, Canada, France and the Soviet Union. Each contributed a portion of the design. I designed the ground station receiver and tracking system and was sent by NASA to Moscow in 1982 for the final test in a lab with all the hardware from each country. Regards, Jeffrey Pawlan ___ time-nuts mailing 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] oscillator aging
On Tue, 2 Oct 2007, Rick Karlquist wrote: No oscillators are in the non aging category. Very true! For fun and education, perhaps someone local to me in San Jose would like to test the aging of a HP precision oscillator standard that has been powered almost continuously for a half century! It is a 107BR 5MHz standard which contains a wonderful crystal that HP used to make themselves. The only time it has been unplugged was while transporting it from Eimac a couple of decades ago. I have had it on a ups power system ever since. I have not tweaked the tuning in years nor checked its frequency recently as I am using a disciplined Austron standard with a loran-c receiver for my lab. The meter on the HP107 panel says it is still putting out the right amount of RF power. No repairs in 50 years; that is reliability. Regards, Jeffrey Pawlan ___ time-nuts mailing 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 documents
); SAEximRunCond expanded to false Errors-To: [EMAIL PROTECTED] RETRY When Brooke put up the very first single page of the E1938 hpgl file I converted this to a BW 2400dpi PDF and sent that to Brooke. He did not send me any of the other pages nor did he make them available. So I waited until John received them and converted them to GIF graphics. They were nearly unreadable here so I asked John for all of the HPGL files. I converted all of them using an older program that I use for my CAD/CAM work. It is CAM350 version 7. Its main function is to check and edit Gerber plots in great detail. I remember paying around $1K extra for the optional HPGL and DXF conversion capabilities. I have sent a zip archive containing all of the high resolution PDF files to John who will then put it up on his website. I am not including the PDFs that Rick very kindly provided as these are already on Brooke's website. Regards, Jeffrey Pawlan WA6KBL Pawlan Communications ___ time-nuts mailing 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] Fw: UNIQUE CLOCK
); SAEximRunCond expanded to false Errors-To: [EMAIL PROTECTED] RETRY On Tue, 11 Sep 2007, Rex wrote: That site seems to be browser-dependent. I works under IE but not Firefox. Do others see the same behavior? Rex, it works fine under the new mozilla version called Seamonkey. I have installed this on my Sun workstation running Solaris 9. Seamonkey has a few problems like complete crashes with Flash websites and occasionally on the yahoo website. Otherwise it is an improvement over netscape, firefox, and the last mozilla. ___ time-nuts mailing 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] Austron 1120 questions
); SAEximRunCond expanded to false Errors-To: [EMAIL PROTECTED] On Wed, 18 Jul 2007, Björn Gabrielsson wrote: Just got my hands on a 1981 vintage Austron 1120. Nicely marked with serial number, 10MHz output freq, 15 VDC input. There are coarse and fine freq tuning. But the four solder pins are just marked E1, E2, E3, E4. With the E4 being the closest to the freq adjustments. I too have one dated 4/81 and the previous owner hand labelled the pins. I have not tested it to verify whether it was correct: E1 10MHz out E2 +15v E3 also +15 E4 DC return I do not know why E2 and E3 are both tied together. Perhaps one is the oscillator and the other is the oven. 73, Jeffrey Pawlan WA6KBL ___ time-nuts mailing 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] Neat toys on eBay for PN measurement
); SAEximRunCond expanded to false Errors-To: [EMAIL PROTECTED] On Tue, 10 Jul 2007, Grant Hodgson wrote: I've been wondering if it would be possible or practical to replace the internal Step-Recovery Diode comb generator in the 11729B/C with one of the Non-Linear Transmission Line comb generators from Picosecond Pulse Labs. Yes, it is just a matter of economics. I seem to recall them telling me that in small quantities (10pcs) the price was around $8000. That was last year so maybe the price has come down somewhat. 73, Jeffrey Pawlan WA6KBL ___ time-nuts mailing 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] new paper on Allan Variance errors
Sorry about that. The IEEE used to charge $5 so that I why I wrote nominal. On Thu, 14 Jun 2007, Brooke Clarke wrote: There's been quite a bit of discussion of how Google will point you to I get this very thing for all the other professional societies that have good papers but I am not a member of those. Some charge horrendous amounts. Some even demand a year's subscription just to download one paper. Sometimes I find that I need the paper badly enough that I write to the authors and ask them for a copy. Most will be happy to send it to you. I did this to A. Poddar at Synergy Microwave who has published several papers usually with Rohde on microwave oscillators, phase noise, and also mixers. He refused to send me a copy of any of his papers and simply told me to buy them from the IEEE or the other organizations where he presented them. An annoying alternative for me is to drive up to the Stanford Univ engineering library and photocopy them. The time spent plus the parking cost me a lot more than $35 and I think IEEE knows that and thus increased their price. Regards, Jeffrey Pawlan ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
[time-nuts] new paper on Allan Variance errors
The latest IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control (May 2007) has a very important paper by Dawkins, McFerran, and Luiten Considerations on the Measurement of the Stability of Oscillators with Frequency Counters Many of us use or have used a high resolution reciprocal counter to measure short term stability of a source. This paper shows that the result is often off by 33% and can be off by more than an order of magnitude, depending on the amount of frequency and phase noise in the DUT. Regards, Jeffrey Pawlan Pawlan Communications ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] HP 5061A at auction
The label on the front makes me worried that is says far more than the word Good. I think Telogy would not be getting rid of this if the tube were good. ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] old freq standards
Since Symmetricom has recently purchased the entire line of frequency and time products from Agilent, Symmetricom has already announced that they will discontinue support of most of them. They are notoriously unhelpful even for current products they manufacture. Other old manufacurers have already discarded all documentation and spare parts. So my advice is to avoid buying all older atomic standard units made by Varian, Trak, and HP unless you have more than one to use for parts. ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] sound card accuracy and html in messages
I would welcome a means of providing an external clock signal to the Delta-44, if you are able to find out how to do this. I have my spam filter intentionally set to put all messages with HTML in the spam trash. I do not mind attachments when they are relevant and executables do not bother me because I am running Sun Solaris (unix). I thank the list owner for not allowing HTML. We do not need pretty formatting, colored words, or Microshaft Office commands that usually take a minimum of 30k just to send one sentence! 73, Jeffrey Pawlan ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] Upper limit on phase noise from two oscillators.
On Wed, 27 Apr 2005, David Kirkby wrote: if one oscillator was perfect (no phase noise at all) also wrote: If one oscillator was noiseless If you or any one on this list has a lead about where to find a noiseless oscillator, PLEASE let me know immediately. I want one! On Wed, 27 Apr 2005, Mike Feher wrote: This does not seem to make sense. No matter what you are measuring it is assumed that the phase noise of the item being measured is greater than the piece of test equipment doing the measurement, else you would not see it. That is the correct description for using a Spectrum analyser to measure phase noise. I have the HP phase noise measurement utility built into my spectrum analyser and as long as the signal being measured is at least 10dB worse than the noise floor of the spectrum analyser noise floor, the readings are reasonably accurate. But there is no spectrum analyser made that is good enough to measure a precision oscillator like the 10811. Therefore the measurement is done by mixing two of them together and one must phaselock one oscillator to the other and drive the mixer ports at 90 degrees from each other. The resulting output is zero frequency (DC) and an audio spectrum analyzer reads the sidebands which is the summed phase noise of the two. Mike, you forgot that the audio spectrum analyzer does not need to have the dynamic range of the phase noise unless you are measuring quite close to the carrier simultaneously with measuring far from the carrier. If you add high pass filters you can make your measurements in segments so that a modest audio spectrum analyser will work. You may have also forgotten that the carrier becomes a DC voltage since the two oscillators are phase locked to each other. You must use a blocking cap (minimal HPF) to not overload the inout of the soundcard if it is DC coupled. I hope this helps but I need to get back to work now. 73, Jeffrey Pawlan ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
[time-nuts] re multiplication to measure phase noise
Yes, you can mulitply and I do that as well. But this a part of the measurement techniques and not really part of the discussion at hand. Besides, the multiplication scheme adds noise and you must calibrate that to be accurate. If they do not have a means of phaselocking and comparing two relatively equal oscillators at its fundamental frequency, then it does not matter how many times they multiply it. Using a millimeter wave spectrum analyzer does not really change this inaccuracy as the noise floor of the spectrum analyzer goes up with each range multiplication so it does not allow you to measure a 10811 even at 40GHz. You can't get something for nothing. You can definitely benefit from the multiplication ONLY if you know exactly what the multiplier contribution is and then use a phase detector at the mm-wave frequency and thus are getting back to DC/baseband and not reading this on an RF spectrum analyzer. I do not know whether your time spent measuring the phase noise of mm-wave sources was for ham radio or for work. If it is for a very important work project, then ask them to invest in the Poseidon (spelling?) oscillators from Australia. They are using machined sapphire cavities suspended in liquid helium as the resonant structures. These are in the 10-12 GHz range so you would need to then multiply them up. There are lots of papers in the IEEE UFFC Transactions. 73, Jeffrey Pawlan ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] Book: Phase Noise in Signal Sources by Robins.
On Mon, 25 Apr 2005, David Kirkby wrote: I won an auction on eBay for a book PHASE NOISE IN SIGNAL SOURCES, IEE, by W P ROBINS. Yes I have this book and it has been helpful but not always correct. I do recommend owning it though. Jeffrey Pawlan ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] Phase noise measurements - getting started.
Regardless of whether you build your own phase noise measurement setup from parts or whether you purchase an already complete system made by Agilent or others, you will still face the reality that there are only three ways to measure phase noise and you mentioned them in your previous email: 1. Start with a frequency source that is more than 10dB better phase noise than the one you want to measure. This is difficult when measuring a HP10811 2. Use two or three identical oscillators. This works if all are really the same but does not work if one of them is significantly different. 3. For measuring much poorer phase noise sources and for measuring further from the carrier than we are interested in, one uses a delay line discriminator. Having access to a calibrated commercial measurement system will not assist you at all unless you can find other oscillators that meet the criterion. Those systems do not contain the comparison signal sources unless you are measuring something with phase noise much poorer than the 10811. Then they are simply using a moderately low noise synthesised signal generator as one of the comparison sources. 73, Jeffrey Pawlan, WA6KBL IEEE, MTT and UFFC ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] GPS Serial Data Causes Mouse Pointer to Move
A similar problem occurs with earlier Windoz versions (98 and 2000). ALWAYS start your notebook computer and let it completely boot and login before connecting anything to the serial port. I found that if there is a GPS connected to the serial port as it is booting, then Windoz thinks this is a mouse and ignores the mousepad or the USB mouse and instead the cursor jumps around the screen as you described. The solution is to shutdown the computer and reboot without the GPS connected until Windoz is already running. Then the OS already knows about the mouse and knows that it is not on COM1. 73, Jeffrey Pawlan, WA6KBL ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
