Re: [time-nuts] OT: Verilog/VHDL discussion list created...
At 01:40 PM 4/14/2009, Luis Cupido wrote: I believe it is to be ham or hobby oriented Am I right ? (If so some rewording of the list purpose might be adequate... thinking out loud...) The description does say: Focus includes but isn't limited to amateur radio and metrology applications. So I think your question is already covered Luis. John Luis Cupido ct1dmk. Scott Newell wrote: At 12:29 PM 4/14/2009 , John Miles wrote: ... for those who would like to participate in HDL discussions that aren't on-topic for existing lists: http://groups.yahoo.com/group/HDLTalk Any VHDL or Verilog HDL-related topics are welcome. How will this compare to comp.lang.verilog, comp.lang.vhdl, and comp.arch.fpga? ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. -- No virus found in this incoming message. Checked by AVG. Version: 7.5.557 / Virus Database: 270.11.55/2057 - Release Date: 4/13/2009 5:56 PM ___ time-nuts mailing 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] Reverse isolation
At 06:14 PM 3/8/2009, Didier wrote: This question is directed at Bruce, but if anyone else has a contribution, feel free to speak. Bruce, What is the best way to measure the reverse isolation of an amplifier (particularly a buffer amplifier for a 10 MHz reference), when it is expected to be in the order of 100 dB or more? Feeding the output with a known signal and measuring at the input with a spectrum analyzer comes to mind, but I am sure there must be something wrong with that technique, it sounds too simple. No, not really. How else would you measure it? Reverse isolation is basically the reverse gain - S12 - of the amplifier. How does a VNA measure S12? Essentially inject a signal at port 2 and see how much comes out of port 1. If you want to get so picky as to determine S12 with a signal in the forward direction then you have a problem. Because the forward gain - S21 - is going to effectively swamp the signal going the other way. So this is almost impossible to measure if the signals are at the same frequency. In this case measure the S-parameters of the amplifier in its 'normal ' configuration, then de-embed the S-parameters of the device. Assuming the device is the only non-linear element you are dealing with then from the S12 S22 values you can also figure out how the device reacts in the reverse direction. Then if you don't mind solving a large matrix you can figure out how the device might react to passing a signal in both directions. The reality is however that if the device is within its linear range, which it is likely to be if you want to distribute a reference or some such, the reverse behaviour of the well terminated amplifier will approach the nominal S12 value. The difficult part is to determine what happens when the amplifier is not nicely terminated! John The presence of a signal at the input (or not) may affect the operating point of the amplifier, so measuring from output to input without such signal may not give a true result. Didier ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. -- No virus found in this incoming message. Checked by AVG. Version: 7.5.557 / Virus Database: 270.11.9/1989 - Release Date: 3/7/2009 6:43 PM ___ time-nuts mailing 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] Never mind Thunderbolts...
At 07:59 PM 2/23/2009, you wrote: Can TAPR put together a group buy on these? http://www.teachspin.com/instruments/optical_pumping/index.shtml -- john, KE5FX An absolute bargain at just $16,000! Wonderful, do I get a bulk deal for two? LOL John ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Off Topic question...
At 02:17 AM 1/20/2009, you wrote: Chuck, Well, I've heard the same sort of stereotypical comments about the Brits so many times I am fed up with them too. Besides which of those comments can you say does not have an air of truth about them for someone coming from England, or may other places in the World for that matter. You've turned a simple friendly poke at the US system into an all out attack on every US citizen. I read an article the other day about the British hacker who broke into the military systems over there looking for UFO data. The comments were that he should be given 70 years inside, executed, and a whole lot of stuff about how this guy was such a terrible criminal. No one talked about how the US military had connected a system with secret classified data onto the Net with no admin password. But apparently all the blame was on him. If you leave your car with the door open and the keys in the ignition wouldn't you expect to have it pinched. And whats this stuff about the land of the free, you guys have more legislation on yourselves and on other countries people than many other countries. I sat and watched all the discussion about shooting guns at New Year and the chances of people getting killed. They get killed anyway because it is so easy to get guns over there. Everybody gets the chance to be a crim. Our police don't carry guns routinely and we don't have a gun problem. Sure some idiots get hold of them, and some innocent people get hurt or killed, but it's a major event in this country when that happens, not just the way of life it is for you guys. So please don't come back at me all innocent like and hurt. Regards, Steve Steve, What you need to remember is that some Americans have a superiority complex - there is nothing of worth or value from anywhere else. We shouldn't take this to heart, this is the way they are educated. From a very early age Americans are taught that the US is the greatest country in the world. The American military is invincible, the American education system excels and everybody in the world wants to live in the US so we need to keep them out. Parts of this are true, the US is a great country. But no more so than Britain, Canada, Australia, Germany or just about any other country. Americans are proud of their country, but often unjustifiably so because their media and education system is severely xenophobic. The American military isn't bad, but invincible? Hardly. The US does have some good universities, but it doesn't mean any means have a caveat on good education. Illiteracy rates in the US are high for a first world nation. But to understand the attitude you need to know a lot about the US. Since 1973 I have lived in the US on several occasions. I have worked for US corporations and the US government. I have also had to live in a country where the rest of the world barely exists for the media. Where major government figures at the Federal and State level are almost totally ignorant of even their closest neighbour. So these days I live in a community of malcontents! Many of my friends here in Canada are Americans who have chosen not to live in the US for a variety of reasons. As an immigrant to this country I have spoken to many people to try and figure out how Canadians define themselves. The one core theme I detect is we are not Americans. Having lived in the US I am happy not to live there now. But don't be discouraged, the sort of reaction you have seen here is fairly typical. On the whole Americans are very sensitive about any perceived criticism of their country and just don't seem to have a handle on anyone else's sense of humour. John (An Australian who has lived in too many places to recall). ___ time-nuts mailing 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] PCB for frequency dividers
At 06:34 PM 7/24/2008, you wrote: Yikes, those are both expensive. http://myropcb.com/ Online quote system is very accurate. I have used them for 12x13inch 6 layer, very reasonable and plenty of smaller 2 and 4 layer PCB's. They are reliable, speedy and accurate. John Try these people: S1D13513 Check out MYLYDIA.COM ... for around $720 ($320 setup plus $0.20 / sq in x 2000 sq in minimum) you can get 115 circuit boards with solder mask and silk screen ($6.30 per board if you can sell them all). Even if you sell a dozen of them, it's cheaper than what you are considering... _ Keep your kids safer online with Windows Live Family Safety. http://www.windowslive.com/family_safety/overview.html?ocid=TXT_TAGLM_WL_family_safety_072008 ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. -- No virus found in this incoming message. Checked by AVG. Version: 7.5.524 / Virus Database: 270.5.5/1571 - Release Date: 7/24/2008 5:42 PM ___ time-nuts mailing 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] PCB for frequency dividers
Oops! Left out the link: http://www.myropcb.com At 09:14 PM 7/24/2008, you wrote: At 06:34 PM 7/24/2008, you wrote: Yikes, those are both expensive. http://myropcb.com/ Online quote system is very accurate. I have used them for 12x13inch 6 layer, very reasonable and plenty of smaller 2 and 4 layer PCB's. They are reliable, speedy and accurate. John Try these people: S1D13513 Check out MYLYDIA.COM ... for around $720 ($320 setup plus $0.20 / sq in x 2000 sq in minimum) you can get 115 circuit boards with solder mask and silk screen ($6.30 per board if you can sell them all). Even if you sell a dozen of them, it's cheaper than what you are considering... _ Keep your kids safer online with Windows Live Family Safety. http://www.windowslive.com/family_safety/overview.html?ocid=TXT_TAG LM_WL_family_safety_072008 ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. -- No virus found in this incoming message. Checked by AVG. Version: 7.5.524 / Virus Database: 270.5.5/1571 - Release Date: 7/24/2008 5:42 PM ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. -- No virus found in this incoming message. Checked by AVG. Version: 7.5.524 / Virus Database: 270.5.5/1571 - Release Date: 7/24/2008 5:42 PM ___ time-nuts mailing 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] PCB design questions thread II
At 08:04 PM 6/2/2008, you wrote: Personally I *hate* turning boards over and clipping leads. And I'd much rather layout SMD than T/H. A man after my own heart. 0.5mm and even 0.4mm pin pitch is fine, QFN is doable, but takes patience sadly BGA is a bit beyond the pale for me right now until I get some more gear. Until I started the job I have now I hadn't done any PTH in nearly 15 years - and now I know why! And now I know why we have technicians to assemble prototypes, but none of them can outdo me for speed and accuracy on an 0.5mm PQFP FPGA. If you are going to do a lot of SMT work by hand, then a good stereo microscope and a Metcal MX500 series iron are almost indispensable. John ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Spec An for phase noise measurements
3562's or 3563's are not expensive. John At 04:18 PM 1/21/2008, you wrote: On Jan 21, 2008 12:41 PM, John Miles [EMAIL PROTECTED] wrote: John, I'm a little confused as to what you are suggesting. An 8662A is about $1500, and the 11729C is about $3k. What would I get for $25? The parts needed to implement Wenzel's app note: http://www.wenzel.com/documents/measuringphasenoise.htm I don't know exactly what is involved with the 11729 and how it makes measurements. Take an hour and look through this HP app note (large file, but only about 50 pages): http://www.thegleam.com/ke5fx/gpib/5952-8286E.pdf It is not all that specific to the 11729B/C despite making frequent references to it. Makes sense now. One problem -- the 8596E only goes down to 9kHz, at least according to the specs. Matt ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. -- No virus found in this incoming message. Checked by AVG Free Edition. Version: 7.5.516 / Virus Database: 269.19.8/1235 - Release Date: 1/21/2008 9:39 AM ___ time-nuts mailing 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] Spec An for phase noise measurements
At 04:57 PM 1/21/2008, you wrote: 3562's or 3563's are not expensive. Yep... I went over to a local fellow's house the other day to buy a 3561A he had for sale, and he talked me into taking his 3562A as well. Both were cheap to acquire, and they're both good analyzers, but neither of them are interesting by current performance standards. Well, I only said they were cheap! I have been using a 3563A for many years - because it is in an automated system. But something a little smaller and lighter would be welcome one day! John I will keep the 3561A because it completes the 3048A PN system I'm putting together, and because it's an amazingly-nice piece of gear even by HP standards. It's as if HP contracted the packaging and UI design out to Apple or Sony, with a nod to Tektronix's 453/454. But I'm not sure the 3562A can justify the space it takes up. I'd like to build a cross-correlating PN rig at some point, but it will use a more-modern ADC platform, one that doesn't weigh 50 pounds and take up 600 square inches of bench space in exchange for 80 dB of dynamic range. -- john, KE5FX ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. -- No virus found in this incoming message. Checked by AVG Free Edition. Version: 7.5.516 / Virus Database: 269.19.8/1235 - Release Date: 1/21/2008 9:39 AM ___ time-nuts mailing 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] Triaxial Connectors
At 05:53 AM 12/10/2007, Arnold Tibus wrote: HP did apply for their RF-cable another PN from a company with an S as symbol inside a kind of triangle with the PN 1250-1413. Sealectro ___ time-nuts mailing 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] 3 lug triax plug.
It's a long time since I used a 2801A, but as I recall the connector is much smaller than the triaxial one used on the 3478A system voltmeter. John At 10:10 AM 12/10/2007, you wrote: Here is one source for this connector, http://www.helmut-singer.de/stock/-148524350.html not cheap, especially with the current exchange rate. They also have cut-off used triax plugs but only twin lug. Regards Robert G8RPI Arnold Tibus [EMAIL PROTECTED] wrote: On Sun, 09 Dec 2007 15:21:46 +0100, Bernd T-Online wrote: BTW: I proudly own a HP2801A plus two crystal sensor elements. However I cannot connect them to the instrument, because the 2801A has a special connector for it. It looks like a smaller version of a BNC connector, but the bayonet has three nipples instead of two. Does anyone on the list know what kind of connector that is and where to get the counterpart (plug)? Regards Bernd DK1AG Bernd and the group, the system voltmeter hp 3437A does have this mentioned connector as I see on my old work horse, sure you mean the same. This connector is for double shielded separate isolated or twinax sym. cable as used for very low voltage signals (thus avoiding unwanted gnd loops). The inner coaxial connector is in fact of lower diameter, but the outside shell has the same size as the std. BNC, but instead having 3 guide pins/slots. Trompeter is one manufacturer, unfortunately I have to dig to find my spare connector in the bag with the manuf. type no on. HP does have a cable for RF-equipment Model 11172B with male on both sides. I add some pictures showing plug and connector. I hope it can help clarifying a bit. Kind regards, Arnold, DK2WT ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. - Support the World Aids Awareness campaign this month with Yahoo! for Good ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. -- No virus found in this incoming message. Checked by AVG Free Edition. Version: 7.5.503 / Virus Database: 269.16.17/1179 - Release Date: 12/9/2007 11:06 AM ___ time-nuts mailing 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] 3 lug triax plug.
At 03:25 PM 12/10/2007, Robert Atkinson wrote: Hi John, Is it actually triaxial or just three lug? I've some small 3 lug coax plugs about 1/2 the size of a BNC. The one's in the link are the same size as a BNC. The one in the link looks like a pretty common triaxial data connector, such as the Trompeter that has been referred to earlier. As I recall the one on the 2801A (and it could be 20 years since I have seen one) is way smaller and has three lugs. It also has, IIRC, a stainless body and the outer wall is comparatively thick with a more pronounced chamfer on the outer edge. John Robert G8RPI. John Day [EMAIL PROTECTED] wrote: It's a long time since I used a 2801A, but as I recall the connector is much smaller than the triaxial one used on the 3478A system voltmeter. John At 10:10 AM 12/10/2007, you wrote: Here is one source for this connector, http://www.helmut-singer.de/stock/-148524350.html not cheap, especially with the current exchange rate. They also have cut-off used triax plugs but only twin lug. Regards Robert G8RPI Arnold Tibus wrote: On Sun, 09 Dec 2007 15:21:46 +0100, Bernd T-Online wrote: BTW: I proudly own a HP2801A plus two crystal sensor elements. However I cannot connect them to the instrument, because the 2801A has a special connector for it. It looks like a smaller version of a BNC connector, but the bayonet has three nipples instead of two. Does anyone on the list know what kind of connector that is and where to get the counterpart (plug)? Regards Bernd DK1AG Bernd and the group, the system voltmeter hp 3437A does have this mentioned connector as I see on my old work horse, sure you mean the same. This connector is for double shielded separate isolated or twinax sym. cable as used for very low voltage signals (thus avoiding unwanted gnd loops). The inner coaxial connector is in fact of lower diameter, but the outside shell has the same size as the std. BNC, but instead having 3 guide pins/slots. Trompeter is one manufacturer, unfortunately I have to dig to find my spare connector in the bag with the manuf. type no on. HP does have a cable for RF-equipment Model 11172B with male on both sides. I add some pictures showing plug and connector. I hope it can help clarifying a bit. Kind regards, Arnold, DK2WT ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. - Support the World Aids Awareness campaign this month with Yahoo! for Good ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. -- No virus found in this incoming message. Checked by AVG Free Edition. Version: 7.5.503 / Virus Database: 269.16.17/1179 - Release Date: 12/9/2007 11:06 AM ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. - Sent from Yahoo! #45; a smarter inbox. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. -- No virus found in this incoming message. Checked by AVG Free Edition. Version: 7.5.503 / Virus Database: 269.16.17/1179 - Release Date: 12/9/2007 11:06 AM ___ time-nuts mailing 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] FPGA protobards (was Re: Of rubidium life andpiggy-bank anemia....)
At 01:29 PM 12/1/2007, you wrote: The lack of an FX2 or similar USB chip on the Darnaw board makes me wonder how you're supposed to program it. I don't know about for Xilinx, but for Altera, a Byteblaster cable is pretty easy to make. Low cost varieties exist on eBay too. In fact we use a USB Blaster clone in the lab here from http://www.minford.ca which is a lot cheaper than the Altera version. Currently I seem to be engaged pretty much full-time on some Cyclone-II with NIOS-II projects and I prefer to have the USB-Blaster _NOT_ on the board. Altera have also released a new Cyclone-III module for NIOS-II with a touch screen LCD from only $399 - which includes the USB-Blaster. These are nice alternatives if you don't need a full 'starter kit' board like the ones from Digilent: I decided to try and play with Xilinx parts early this year, but after buying a couple of Digilent boards I found the Xilinx tool-chain something of a pig to use. Maybe I am just too familiar with the Altera tools, so we sold the Digilent boards on eBay. http://www.knjn.com Jean's stuff is good. I have used a number of his small boards (all Altera - we don't do any Xilinx) and they have worked out very well. John Day VE3CJO The same guy who sells these boards also hosts a good FPGA-specific project site/forum: http://www.fpga4fun.com -- john, KE5FX Ulrich Bangert wrote: For that reason I have decided to buy me this smart device and experiment with it: http://www.enterpoint.co.uk/moelbryn/darnaw1.html Wow. That connector looks nasty. What the heck are you supposed to do with that? Let me suggest an alternative. I've used several of the FPGA and CPLD boards made by Digilent. I have been pleased by all of their products so far. http://www.digilentinc.com/ The 3E starter board is $149. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. -- No virus found in this incoming message. Checked by AVG Free Edition. Version: 7.5.503 / Virus Database: 269.16.12/1163 - Release Date: 12/1/2007 12:05 PM ___ time-nuts mailing 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] Danish Question
); SAEximRunCond expanded to false Errors-To: [EMAIL PROTECTED] RETRY At 03:10 PM 10/31/2007, you wrote: ); SAEximRunCond expanded to false Errors-To: [EMAIL PROTECTED] RETRY In message !!AAAYAOYAZyOzV8ERq+LmT45ypI7CgAAAEMh4axYd2AtA [EMAIL PROTECTED], Rob Kimberley writes: The following concerns a question in a physics degree exam at the University of Copenhagen: Describe how to determine the height of a skyscraper with a barometer. [urban legend] The student was Nils Bohr, the first Dane to win the Nobel prize for Physics. No, it most certainly was not Niels Bohr, and I seriously doubt it was anybody, as this particular urban legend was already old when I studied physics... You beat me to it Poul-Henning, the legend is first documented in 1958, but did not involve Bohr. I heard it in 1971 in the UK and gain in 1973 in the US - by then it is attributed to Bohr. Some sources say that Rutherford was the arbiter. Why would Rutherford have become involved? But it is true that around 1911 Bohr did work in Rutherfords laboratory. I later again heard the same legend in California in 1976, but about some other eminently undistinguished candidate, not Bohr. John Poul-Henning -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 [EMAIL PROTECTED] | 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. ___ time-nuts mailing 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] Danish Question
); SAEximRunCond expanded to false Errors-To: [EMAIL PROTECTED] RETRY At 03:21 PM 10/31/2007, you wrote: ); SAEximRunCond expanded to false Errors-To: [EMAIL PROTECTED] RETRY My apologies - I have been misinformed! Rob But it's a good story anyway Rob! John -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Poul-Henning Kamp Sent: 31 October 2007 19:10 To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Danish Question ); SAEximRunCond expanded to false Errors-To: [EMAIL PROTECTED] RETRY In message !!AAAYAOYAZyOzV8ERq+LmT45ypI7CgAAAEMh4axYd2AtA [EMAIL PROTECTED], Rob Kimberley writes: The following concerns a question in a physics degree exam at the University of Copenhagen: Describe how to determine the height of a skyscraper with a barometer. [urban legend] The student was Nils Bohr, the first Dane to win the Nobel prize for Physics. No, it most certainly was not Niels Bohr, and I seriously doubt it was anybody, as this particular urban legend was already old when I studied physics... Poul-Henning -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 [EMAIL PROTECTED] | 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. ___ time-nuts mailing 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] Danish Question
); SAEximRunCond expanded to false Errors-To: [EMAIL PROTECTED] RETRY At 03:35 PM 10/31/2007, you wrote: ); SAEximRunCond expanded to false Errors-To: [EMAIL PROTECTED] RETRY At 02:31 PM 10/31/2007 , John Day wrote: You beat me to it Poul-Henning, the legend is first documented in 1958, but did not involve Bohr. I heard it in 1971 in the UK and gain in 1973 in the US - by then it is attributed to Bohr. Some sources say that Rutherford was the arbiter. Why would Rutherford have become involved? But it is true that around 1911 Bohr did work in Rutherfords laboratory. I later again heard the same legend in California in 1976, but about some other eminently undistinguished candidate, not Bohr. So, who's going to submit this urban legend to Snopes for them to track down? It's on snopes as far as I know. John -- newell N5TNL ___ time-nuts mailing 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] Danish Question
); SAEximRunCond expanded to false Errors-To: [EMAIL PROTECTED] RETRY At 03:36 PM 10/31/2007, you wrote: ); SAEximRunCond expanded to false Errors-To: [EMAIL PROTECTED] RETRY John Day escribió: Some sources say that Rutherford was the arbiter. Why would Rutherford have become involved? But it is true that around 1911 Bohr did work in Rutherfords laboratory. And at that time I don't think that Rutherford were interested on knowing from Bohr how to determie the height of a building with a barometer... when discussing matter structure ;) Indeed! I suppose all sorts of stories surround our heroes, many true, many not. Well I remember the legend of Feynman before I met him in 1973 - a totally differnet person to what I was led to believe. John Regards, Javier ___ time-nuts mailing 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] M100 manual
); SAEximRunCond expanded to false Errors-To: [EMAIL PROTECTED] RETRY At 04:00 PM 10/25/2007, you wrote: ); SAEximRunCond expanded to false Errors-To: [EMAIL PROTECTED] RETRY Just to let anyone interested know, I've uploaded an M100.pdf to Ko4BB.com. Phil Couldn't find it Phil, at least not where the other related manuals are. John ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] M100.pdf
); SAEximRunCond expanded to false Errors-To: [EMAIL PROTECTED] RETRY At 06:31 PM 10/25/2007, you wrote: John It's probably still in the upload section Phil G4FXY Aaahh! Then I am sure it will make it out very soon. Thanks ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] [OT] Why did HP use a non standard connector on the 8411 Converter
); SAEximRunCond expanded to false Errors-To: [EMAIL PROTECTED] RETRY At 02:06 PM 9/11/2007, you wrote: Does anyone on this list know why HP used a non standard connector to join the 8411 harmonic frequency converter to the 8410 network analyzer? Have a look at what it does, then you will understand why the same type was used on things like the convertor heads for the 5355 plug-in for the 5345 as well. Apart from supply and control lines there are also several coax cables for sampler drive and IF signals. Of course it is also designed to maintain alignment of the contacts. I used 8410/8411 systems from when they were first introduced back in the early 70's, I have NEVER seen a damaged connector. John ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] [OT] Why did HP use a non standard connector on the 8411 Converter
); SAEximRunCond expanded to false Errors-To: [EMAIL PROTECTED] RETRY At 02:40 PM 9/11/2007, you wrote: Is there a reason to not use the standard D series connectors that can have coax connectors along with the normal contact pins? Poor contact and connector life, imprecise alignment, lack of precisely controlled shielding. The D connectors are not intended to be routinely mated/unmated and become quite erratic after a few cycles (usually 50 or so as I recall) even in a lab environment. They also have fairly significant frequency limitations, but I cannot recall exactly what they are. John ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] [OT] Why did HP use a non standard connector on the 8411 Converter
); SAEximRunCond expanded to false Errors-To: [EMAIL PROTECTED] RETRY At 10:32 PM 9/11/2007, you wrote: ); SAEximRunCond expanded to false Errors-To: [EMAIL PROTECTED] RETRY Thanks John: Makes sense. Until you have a problem on an 8411A or a 5356 convertor! John Have Fun, Brooke Clarke http://www.PRC68.com http://www.precisionclock.com John Day wrote: At 02:40 PM 9/11/2007, you wrote: Is there a reason to not use the standard D series connectors that can have coax connectors along with the normal contact pins? Poor contact and connector life, imprecise alignment, lack of precisely controlled shielding. The D connectors are not intended to be routinely mated/unmated and become quite erratic after a few cycles (usually 50 or so as I recall) even in a lab environment. They also have fairly significant frequency limitations, but I cannot recall exactly what they are. John ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing 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 5370B low frequency modulation
); SAEximRunCond expanded to false Errors-To: [EMAIL PROTECTED] RETRY See: http://journals.cambridge.org/download.php?file=%2FMAM%2FMAM11_S02%2FS1431927605504483a.pdfcode=7eb044ef7101eff8a8274c4fdfabca59 and http://www.tkb-4u.com/articles/soldering/sgons/sgons.php There is also at least one US patent deals with using pure tin instead of gold for solderability. The problems are also well known to anyone working with flip-chip bonding where gold bumps have been used. Both tin and gold have been known to grow crystalline whiskers, one microscopy journal carried a paper a couple of years ago from Sandia Lab on the subject. Tin whiskering has been well known for many years. John At 11:21 AM 8/30/2007, Richard (Rick) Karlquist wrote: ); SAEximRunCond expanded to false Errors-To: [EMAIL PROTECTED] RETRY Gold mixes with solder to from an intermetallic that suffers from embrittlement. I am not aware of silver solder being a remedy. I have heard of assembly lines that do not allow any gold whatsoever in the building! I heard our assembly line manager at work just last week lecturing yet another engineer about NO GOLD. Period! Furthermore, gold plated brass connectors screwed into aluminum (with corrosion treatment) (no soldering) will corrode in a salt spray environment. I guarantee it. We always used stainless for military work. Rick N6RK Brooke Clarke wrote: Hi Didier: Would you elaborate on the comment Gold plated connectors are a well known example. Do you mean when soldered with Lead Tin solder instead of a silver bearing solder or something else? Have Fun, Brooke Clarke http://www.PRC68.com http://www.precisionclock.com Didier Juges wrote: ); SAEximRunCond expanded to false Errors-To: [EMAIL PROTECTED] I have seen cold solder joints on thermal fuses and certain types of capacitors, while the rest of the instrument was fine with no sign of corrosion. I think it has to do with the metal used for certain component leads. Either they were never soldered well, or interface corrosion developed over time. Gold plated connectors are a well known example. Didier KO4BB -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Mike Feher Sent: Sunday, July 22, 2007 9:58 PM To: 'Discussion of precise time and frequency measurement' Subject: Re: [time-nuts] HP 5370B low frequency modulation Highly unlikely, but, possible, especially if it was in a corrosive atmosphere. Of course then I would expect to see evidence of corrosion on other components. ... Mike B. Feher, N4FS 89 Arnold Blvd. Howell, NJ, 07731 732-886-5960 ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] 15 ns vs. 15 nS
At 10:30 AM 5/22/2007, you wrote: John Day wrote: At 09:26 AM 5/22/2007, Didier Juges wrote: Having been on the western side of the pond for too long (people here could not care less about SI units, they drive on parkways and park on driveways anyhow), I got bad habits, sorry... We'll forgive you Didier! I find the same thing up here in Canada despite the fact we are slightly more metricated than the US. However I just cannot bring myself to give up 'English' spelling. Canada is confused, they spell some things English style, and other things US style. But for me it is still colour, programme and metre. John That's OK, you should hear a conversation at home between my children and me. It would make a franco-english canadian cringe... Funniest thing is I have a very good friend, a librarian in Paris, who comes to Canada regularly. He prefers to converse in English with Francophone Canadians because he says it is easier to understand than the 18th century, rural France, based accent of the French spoken here. Now, the funniest part was when I started here some 20 years ago, and I went to the secretary and asked for a rubber... She sent me to the stock room, who sent me to someone else. It took me 3 stops to realize they were having a good time at my expense... Just as well you didn't go into the pharmacy and ask for a French Letter, the colloquial name I grew up with for the same thing! John Didier KO4BB ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] 15 ns vs. 15 nS
At 10:13 AM 5/22/2007, you wrote: In Imperial measure, 8 pints make a gallon and 2 pints make a quart. US quarts???... Two Imperial pints makes an Imperial Quart, as it does in US Customary measure. :-) Rob -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Chuck Harris Sent: 22 May 2007 15:04 To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] 15 ns vs. 15 nS Rob Kimberley wrote: Happy memories... I remember being switched half way through my A Level Physics course from cgs to MKS in 1968. Legal here in UK to show weights measures in shops in both metric and imperial systems. Fuel at petrol (gas) stations sold in litres, and distance on roads still shown in miles (!!). Never did understand how the US gallon was smaller than the Imperial one though... Pretty simple, really, a US gallon is 4 quarts (as in quarters), an imperial gallon is 5 quarts. The real question is when did the imperial gallon pick up the extra quart. -Chuck Harris ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] 15 ns vs. 15 nS
At 03:15 PM 5/22/2007, you wrote: At 02:55 PM 5/22/2007, Chuck Harris wrote... Rob Kimberley wrote: In Imperial measure, 8 pints make a gallon and 2 pints make a quart. US quarts???... US quart is 32 oz, and 4 of them makes a US gallon. 5 makes an imperial gallon. No, because US and Imperial ounces are not the same. A US ounce is 231/128 in^3. An Imperial ounce is 1/160 x 4.54609 liters (~277.42/160 in^3). Roughly, US = 1.8 in^3, Imp. = 1.73 in^3. US gallon = 231 cubic inches Imperial gallon = 277.42 cubic inches 5/4 of a US gallon is 288.75 cubic inches, so no, the relationship doesn't work. John ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] 50 vs 75 ohm cables
At 02:52 AM 5/11/2007, Peter Vince wrote: Thank you all for your replies. As I should have guessed, a simple question leads to a long and complicated answer! Of course! One of the truly fun things about groups such as this one is that we have people with an enormous wealth of knowledge. I know the same happens in the [mailto:hp_agilent_equipment%40yahoogroups.comhp_agilent_equipment] group and I am sure it happens in others. John Peter ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] 50 vs 75 ohm cables
At 03:26 PM 5/11/2007, you wrote: [EMAIL PROTECTED] said: I can confirm that the choice of 75 Ohm for telecom use indeed is because of the low attenuation. The first use of coax was for Carrier Frequency systems, where a number of telephone conversations were AM modulated on individual carriers, usually 4 kHz apart. What's the attenuation mechanism? I thought the old 10 megabit vampire-tap Ethernet picked 50 ohms because of lower attenuation. The story I remember is that for a given outside diameter, the inside diameter was bigger at a lower impedance. The main losses were resistive on the center conductor due to skin effect. A bigger center conductor had more area at a given skin depth and hence lower losses. In fact that is correct. The Bell Labs experiments were done with a constant size CENTRE conductor. But there was an over-riding concern with the Ethernet developers - if they chose a 75 ohm cable then it was felt that it was inevitable that somebody would use 'F' connectors and cheapen the whole thing down. If they stuck with 50 ohm then it was easy to stay with BNC. In the Ethernet era you are referring to though, the timing limits the length of the Ethernet. I recall having some pretty horrible RG-58 style cable in a huge pile on the floor of the lab with as many taps as we could put onto it and the losses were not enough to stop it. John -- These are my opinions, not necessarily my employer's. I hate spam. ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] 50 vs 75 ohm cables
At 11:00 AM 5/10/2007, WB6BNQ wrote: Hi Peter, snipped In an effort to standardize, the industry selected the mid point between the 35 Ohms and the 72 Ohms, that being 50 Ohms. This forced the antenna manufacturers to design their antennas for 50 Ohms or provide a matching network. Nice thought, but in fact the comments made earlier are more correct. Early co-axial connectors go back to Belling-Lee in the UK in the early 20's with what has now become the IEC-692 or 'PAL' connector. Although not a controlled impedance connector it made the use of coaxial cable convenient. But like most coaxial components it need to wait for radar to become really useful. During the war it was used for video and IF connections in radar equipment. 52 ohms was in fact the compromise. In 1929 experimental work at Bell Laboratories found that the ideal impedances for coaxial cable were 30 ohms for high power, 60 ohms for high voltage and 77 ohms for low attenuation. Thirty ohm cable is very difficult to make, not very flexible and is expensive. So the Bell folk decided that 52 ohms was the best compromise between 30 and 60 ohms. This has become the 50 ohm cable we know today. Seventy-five ohms is also a compromise, in fact a folded dipole has, if I recall correctly because I cant check any books as I am away from the office, a feed point impedance of 73 ohms. So 75 ohms as we know it now is a compromise between the low attenuation 77 ohms and the 73 ohm dipole feed-point. We also tend to think in terms of ONLY 50 and 75 ohm. But in fact (again IIRC) RG-8 cable is actually 52 ohms, RG-59A is 73 ohms (wonder why!) but RG-58B is 75 ohms. RG-11, which found use for video cable during the war is 75 ohms. But amongst the older cables their are cables at 52.5, 51, 76 as well as 50, 52 and 75 ohms. Newer types tend to be either 50 or 75 ohm with 93, 120, 125 and even 950 ohm available for special uses. The television world originally used 300 Ohms at the antenna, along with 300 Ohm Twin Lead and the 300 Ohm input to the television itself. The reason for the 300 Ohms was due to the use of a folded dipole which has a characteristic impedance of 300 Ohms. Well, again IIRC, it is not actually 300 ohms, if memory serves it is in fact more like 273 ohms - plus or minus the effect of conductor sizes. The folded dipole design could be tweaked to provide a wide frequency range needed to cover all the TV frequencies, especially with the UHF channels. The switch to coax for TV use came about in an effort to prevent or greatly reduce ghosting problems and for cable systems as a reliable means of transporting the signals to many locations. Twin Lead cannot tolerate being near metal objects and is unable to be buried. Coax contains the signal entirely within its own shielded structure and therefore can be buried and laid next to other metal objects without degrading the signal quality. The reason 75 Ohms was selected for the TV world was because a simple, easily constructed, 4:1 balun (transformer) would transform 300 Ohms to 75 Ohms. That factor accelerated its acceptance. But in fact 75 ohms was well established in the TV industry before coax found its way to the receiving antenna - as the cable for carrying video signals due to the lower losses it exhibited when coax ran all the way around buildings carrying video. Although other cable types (especially a shielded twisted pair amongst them) were tried, manufacturers were already making lots of 75 ohm coax so it was cheap and readily available. The fact that blind freddy could wind baluns cheaply just made it more economical. It is said by some historians of television that 75 ohms was adopted early on because of low losses and the fact that 75ohms could easily be made in resistors (for terminations and feed resistors) by paralleling two 150 ohm units before the E-24 values became common. Trying to go from 300 Ohms to 50 Ohms would require a 6:1 ratio with increased I/R losses and greater difficulty in obtaining wide band operation in the early days of ferrite mixes. Remember also that early television antenna baluns didn't use ferrite at all! Many of them were reasonably large and used 'air' cores. Baluns with ferrite cores only became common much later because they could be wound by automatic machines and were better on UHF, although many viewers would never have noticed the difference. A few points of reference: Coaxial cable was invented in 1884 and patented in Germany by Ernst von Siemens, the founder of Siemens. But nothing really happened as they couldn't figure out a use for it. About a decade later Tesla took out a US patent , which you should be able to find at the USPTO website. Crudely made coaxial cable, or perhaps more correctly, shielded cable of coaxial construction is found in the UK in the early 20's. In the US it was not until the work at Bell Labs in 1929 that coax became widely known there. Connectors were
Re: [time-nuts] 50 vs 75 ohm cables
At 01:50 PM 5/10/2007, WB6BNQ wrote: John Day wrote: At 11:00 AM 5/10/2007, WB6BNQ wrote: Hi Peter, snipped In an effort to standardize, the industry selected the mid point between the 35 Ohms and the 72 Ohms, that being 50 Ohms. This forced the antenna manufacturers to design their antennas for 50 Ohms or provide a matching network. Nice thought, but in fact the comments made earlier are more correct. Early co-axial connectors go back to Belling-Lee in the UK in the early 20's with what has now become the IEC-692 or 'PAL' connector. Although not a controlled impedance connector it made the use of coaxial cable convenient. But like most coaxial components it need to wait for radar to become really useful. During the war it was used for video and IF connections in radar equipment. The reason that coax was not widely used was due to cost. It was readily available in large quantities, so the only people able to get and use it were the Government and government funded research. Oh? Where did that information come from? 52 ohms was in fact the compromise. In 1929 experimental work at Bell Laboratories found that the ideal impedances for coaxial cable were 30 ohms for high power, 60 ohms for high voltage and 77 ohms for low attenuation. Thirty ohm cable is very difficult to make, not very flexible and is expensive. So the Bell folk decided that 52 ohms was the best compromise between 30 and 60 ohms. This has become the 50 ohm cable we know today. I do not directly know of the referenced Ma Bell experiments. However, if such claims were made, it was certainly taken out of context ! Without the context or application that was being researched these numbers have little meaning. I am sure a reference to the appropriate material will be forthcoming as I recall that ATT filed for some more patents in 1929. Again I am truting my memory, but the scientists concerned were Lloyd Espenschied and Herman Affel. We can assume that they were aware of the work of Siemens in 1884, Tesla in 1894 and also Oliver Lodge demonstrated the wave guide effect of a coaxial structure in either 1892 or 1894. In 1907 Vail (one of Bell's partners) who was to become president of ATT combined the Western Electric and ATT research facilities. Before his death in 1920 he had been pushing for a method of increasing the bandwidth of the cable systems then in use. Twisted pairs suffer a plethora of disadvantages. Espenschied and Affel were charged with understanding the nature of cables of all types this priority was laid down by Vail himself. 1929 became a very significant year - it was in January that the decibel officially became the unit if measuring line loss in the Bell System and in May that Espenschied and Affel reported on coaxial cable. In 1931 Espenschied Affel was granted US patent 1,835,031 for broadband coaxial transmission systems. If you search on him you will find a good little bio on the IEEE wesbite. Lloyd Espenschied only died in 1986 and I had the fortune to meet him at a symposium in 1974 when he would have been in his mid 80's. He was the inventor of the loading coil for telephone systems and also held a patent on quartz crystal resonators used in filters. At Bell Labs, and anywhere else at the time, nobody really understood what coaxial cables could do. My understanding is that they started with a single solid centre conductor and made a whole range of cables covering a variety of impedances. Both Espenschied and Affel had been involved in the first carrier multiplex system produced by Bell which was used between Baltimore and Pittsburgh in 1916. It was the problems associated with this that finally drove the work on coax. Affel became involved as a result of his collaboration with Arthur Kennelly ( of Kennelly-Heaviside layer fame ) in 1916 at MIT where they published a paper on the skin effect in conductors at high frequencies. Kenelly had worked with Edison until 1893, the same year in which he published a most important work on impedance in which he used complex quantities. This skin effect work was all the more remarkable because the research was carried out at 100kHz. As mentioned earlier, the Espenschied and Affel cable consisted of a sold centre conductor placed inside a tube and supported by insulating washers. Hard on the heels of this work ATT laid an experimental coaxial cable between New York and Philadelphia in 1936. I don't know if the ARRL's QST CD-ROMs have all the advertisements in them, but you might want to look at the December 1945 issue where Amphenol published the first advertisements that I have been able to find for coaxial cable. Why make coax for 30 Ohms when no systems were in existence that utilized
Re: [time-nuts] 50 vs 75 ohm cables
At 02:31 PM 5/10/2007, [EMAIL PROTECTED] wrote: Hi guys, some practical comments: * 50 Ohms transmission lines are much easier to fabricate on standard 4, 6, or 8 layer PCB's. 75 Ohms traces are very thin and thus have issues in manufacturing accuracy. * Feeding a 50 Ohm source into a 75 Ohm load gives a VSWR of 1.5, a mismatch loss of only 0.177dBm, and a return loss of -13.98dBm, so not much power is lost due to the mismatch loss. Of course at high power the -14dB return is a problem. * 50 Ohm connectors are mechanically more stable and easier to manufacture. 75 Ohm BNC for example removes the internal dielectric and leaves the center pins floating in free air so they can break more easily. * 75 Ohms requires thicker dielectrics, or higher dk dielectrics - tougher to manufacture. * 75 Ohms cables usually use dirt-cheap and flaky F-connectors. These get jammed easily, and every F-Connector I have seen so far has a different center pin length. Whoever designed F-Connectors (and S-Video connectors!!) should be held accountable in my opinion. There are so many better ways to design a (cost-effective) connection. Excellent comments Said. Having spent the last 37 years designing RF and microwave equipment I am rather glad that I don't have to use too many things like 75 ohm BNC. Of much better robustness and performance are things like the 1.6/5.6 and other European type which I have seen precious little of in North America. For years I would not use 'F' connectors at all. But then I didn't live in North America for most of that time and although recent years have seen 'F' types become ubiquitous throughout most of the world, they were thankfully almost completely unknown in the UK, Europe or Australia until then. Because of the smaller centre conductor in 75 ohm cables the support offered by the dielectric is not as great as for 50 ohm and often inadequate to maintain constant impedance. Some types use a foam dielectric which is even more of a pain! Even worse is the poor quality of the cable itself. Often the outer braid has very poor coverage and the cable often behaves more like leaky coax or an antenna array! Fortunately we are seeing more and more DVI and HDMI around here and they seem to have much better characteristics, the S-Video interconnec system is, to put it mildly, worthy of the junk bin! John bye, Said ** See what's free at http://www.aol.com. ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] Last Decembers solar flare
At 08:50 AM 5/1/2007, you wrote: Hi John, Was there a link or attachment to this message? http://www.mwrfnotepad-digital.com/mwrfnotepad/200704/ My apologies for the omission, John Rob -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of John Day Sent: 01 May 2007 12:03 To: time-nuts@febo.com Subject: [time-nuts] Last Decembers solar flare This just came in, thought it might be of interest to those discussing the effect of the flare. John ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] OT: eBay bidding question
At 04:17 PM 4/26/2007, you wrote: In a message dated 4/26/2007 05:23:48 Pacific Daylight Time, [EMAIL PROTECTED] writes: Can anyone propose a sequence of bids on dates that explains this list of recorded bids and dates? I guess there must be one but it is evading me. *Bidder*Bid AmountDate of bid Bidder 6US $4,000.00 Apr-22-07 05:14:15 Bidder 8US $4,000.00 Apr-25-07 00:49:30 Ebay processes the new bid, then checks for existing bids, so in this case bidder 8 bid $4000 and became the high bidder, for just a moment. Then ebay searches for any bids it has on hand to see if they are exhausted, or as in this case bidder 6 had a bid in for the same amount, placed earlier, so he goes to winning bidder. John Could this be because of bid retractions or simply revising a bid? Are the times/dates local time or Ebay UTC? bye, Said ** See what's free at http://www.aol.com. ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] OT: eBay bidding question
At 05:33 PM 4/26/2007, you wrote: When I asked these questions of eBay; the unsatisfactory answer was that only actual bids show. This meaning a new bid submmitted would create new/ additional line, similar to the series of bids on April 23. Is not clear why this bidder put in so many bids within two minutes, since no other bidder's 'proxy' bid shows as exceeding any of his bids. Also does not explain following: Bidder six placed bid on April 22, but his bid does not show until after many other bids are placed on 23, 24, and 25 April. It is expected he would show as a bidder if his bid was 4,000. Sheesh! Think about the process. Bidder 6 bids $4000 on the 22nd. If you watch after each of the bids less than $4000 is placed bidder 6 goes to the top of the list. The system does not show the intermediate steps in bidder 6's proxy progression, each time that somebody makes a bid which is greater than the CURRENT bid amount, by an amount equal to or greater than the computed bid increment it becomes the current high bid, until eBay checks for remaining value in a previously placed bid. You would only see that if you were looking at the item at the right time. John If his bid was less, then he would have needed to bid again; which eBay says would result in the new bid submission being displayed. Tom Buehl At 03:17 PM 4/26/2007, you wrote: In a message dated 4/26/2007 05:23:48 Pacific Daylight Time, [EMAIL PROTECTED] writes: Can anyone propose a sequence of bids on dates that explains this list of recorded bids and dates? I guess there must be one but it is evading me. *Bidder*Bid AmountDate of bid Bidder 6US $4,000.00 Apr-22-07 05:14:15 Bidder 8US $4,000.00 Apr-25-07 00:49:30 Could this be because of bid retractions or simply revising a bid? Are the times/dates local time or Ebay UTC? bye, Said ** See what's free at http://www.aol.com. ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] OT: Audiophoolery
At 04:14 PM 4/20/2007, you wrote: It's the $250 HDMI cable (http://www.audioconnect.com/html/hdmi-3_hdmi_cable.html) that takes the prize IMHO - analog is voodoo to most people and they can be bamboozled by talk of SWR's etc- but digital is just digital - it works or it doesn't. I'd be willing to bet that this $250 cable is no better than the $19.95 one hooked to my Apple TV (neat toy BTW). Or $225 for a metre long coax cable with RCA plugs on it for your digital data? Some years ago in Australia a friend who had 'golden ears' had purchased some insanely expensive speaker cable. But still wasn't happy. He had some custom built cabinets and who knows how much power driving the thing (it was a home brewed thing using KT-88's in ultralinear class-AB1 if I recall). But whoever assembled the speakers had used some really lightweight telephone style wire in the cabinet. The wire had gotten so hot the insulation was 'dripping' off! All I did was replace it with standard 4 (square mm) auto cable, and he was happier than a pig in a pile of excrement. I put up with 10 years of his boasting before I told him what I had used. The day I told him I played a trick on him. I invited him around to hear my system. In those days a pair of home-brewed Klipsch look-alikes. He raved, until he saw that the amp wasn't the big glowing thing on the bench, I was using a simple National Semiconductor LM2875 amp and some standard 3 core mains cable top connect it to the speakers. We still talk, but he is a little less boastful now. Sadly the Corner horns didn't survive a divorce and a move to smaller digs. John Then again most people are happy with a cheap timex and a clock radio - I have three independent GPS clocks and two WWV clocks so maybe I shouldn't be too quick to comment. John (who still wears a mechanical watch) Daun Yeagley wrote: I had passed a couple of these posts on to one of my buddies at Motorola, since we and a few others have by chance been having a parallel discussion of such topics. Check out his message. OK, This is as crazy as it gets. I have seen the high end power cables before and consider this the ultimate in audiophoolishness ... I'm not sure this is the most expensive example, but it surely establishes that there is no connection between reality and audiophoolery. Check it out: http://www.audioconnect.com/html/pk10_palladian.html SWR enhanced God, it's so simple, why didn't I think of it? Jim This one just fit so nicely into our discussions! Daun -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of John Pettitt Sent: Friday, April 20, 2007 1:03 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] OT: Audiophoolery Dr. David Kirkby wrote: On Fri, 2007-04-20 at 02:21, Bruce Lane wrote: Discussions involving audiphoolery, particularly where silly things like $500 knobs and atomic references for CD writing are involved, never fail to amuse me. With that in mind, and given the current thread about Antelope Audio, I feel compelled to point out a link which, I think, illustrates one of the peaks to which audiophools will go to satisfy their obsessions. http://www.monstercable.com/productDisplay.asp?pin=195 I invite all to have a good chuckle over this one. ;-) Keep the peace(es). Take a look at this Aromatherapy and Audiophools which appeared in Electronics World and Wireless World, October 1999. I thought it was so funny I scanned it and stuck it on my web site. http://www.g8wrb.org/useful-stuff/audiophools.pdf I still remember the mercury filled speaker wires post - see also http://www.geocities.com/CapeCanaveral/hall/8701/Audio_BS.htm and in case anybody still needs convincing http://www.avreview.co.uk/news/article/mps/UAN/632/v/3/sp/332683698431330268420 *Harmonic Technology Fantasy *In our test system Fantasy proved to be an extremely charming cable, it is extremely fine and smooth while being able to resolve detail with ease. Acoustic space is well defined and instrument tone is pretty good too. Excuse me while I gag. $900 for a par of 3m wires! John ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] OT: Audiophoolery
At 05:54 PM 4/20/2007, Neon John wrote: On Fri, 20 Apr 2007 16:55:16 -0400, John Day [EMAIL PROTECTED] wrote: The day I told him I played a trick on him. I invited him around to hear my system. In those days a pair of home-brewed Klipsch look-alikes. He raved, until he saw that the amp wasn't the big glowing thing on the bench, I was using a simple National Semiconductor LM2875 amp and some standard 3 core mains cable top connect it to the speakers. We still talk, but he is a little less boastful now. Sadly the Corner horns didn't survive a divorce and a move to smaller digs. I feel yer pain buddy! My real Klipsches didn't survive a fire. Sad, isn't it. But in those days I had a house with a good size listening room ( 16m long, about 6m wide) that could handle them. Gawd I miss those horns. Those proved that excellent speakers make everything else in the system relatively unimportant. And the efficiency! I got turned on to horns by a now sadly departed friend who had some upright folded horns that could fill his place with only three or four watts. John, did you copy the folded horn design or just the looks. The whole nine yards, so to speak. I based the design on a couple of articles, possibly even academic papers, it is a long time back now, that described the horn and its mathematics. I've pondered trying to build another set but I think that degree of woodworking skill is just beyond my capabilities. Well, don't despair. I have seen places that will accurately cut materials for hobby cabinet makers and the likes. I beleive some of them will do speaker stuff as well, give them some good accurate drawings and they will do it. As for me, well it would need to be a design that takes up no more than a square foot of floor space each! John John --- John De Armond See my website for my current email address http://www.neon-john.com Cleveland, Occupied TN All great things are simple and many can be expressed in single words: Freedom, Justice, Honor, Duty, Mercy, Hope. -Churchill ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] Schematic Needed for TrueTime XL-DC
At 11:38 AM 4/7/2007, Jason Rabel wrote: I've discovered that trying to get any schematics from them is impossible, even for old / obsolete equipment. But they love to comment on how you should upgrade to their latest piece of hardware. ;) Why? So you have something that is way more expensive and even less serviceable than the older gear ;) John ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] Converter for Time Signal Reveiver?
At 12:26 PM 4/5/2007, you wrote: My guess is that it is a converter that allows a fixed 10 MHz receiver to receive a range of other frequencies. I can't quite read the tuning dial to see just what range it covers. -mike- Zellwegger was (is?) a Swiss company. Back in the period after WWII they produced some moderately tunable receivers for around 8-15MHz for receiving time signals. I think what is shown here is an up-convertor designed to be used with the Zellwegger unit to receive the signal from the former time and frequency station VNG which had a very good signal on 2.5MHz and another around 4.5MHz. A Zellwegger receiver can be seen here: http://www.radiomuseum.org/forumdata/upload/Swiss%2D2%2Ejpg I would love to know where the convertor came from, I recall seeing a setup like this back in the early 60's in a laboratory with a Bendix BC-221 and some other early frequency counting and calibrating equipment, including a Russian copy of the BC-221. John At 05:19 PM 4/3/2007, you wrote: What is it? http://www.gmat.unsw.edu.au/currentstudents/ug/projects/f_pall/html/s19.html It might be some sort of filter or amplifier for WWV. (Or equivalent down under.) This one shows a recorder that does time stamps. They have to get the time from somewhere. http://www.gmat.unsw.edu.au/currentstudents/ug/projects/f_pall/html/s14.html -- These are my opinions, not necessarily my employer's. I hate spam. ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] Ultra low phase noise floor measuremen t system forRF devices.
At 02:04 PM 4/1/2007, Bob Paddock wrote: [This kind of #)$*#$* in schools, is the kind of thing that makes be believe in Home Schooling.] Yet another reason I am pleased to be home-schooling my daughter! John ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] Government Liquidation
At 11:26 AM 3/19/2007, you wrote: At 16.12 19/03/2007, you wrote: This is kind of on the same topic as the government surplus chit-chat... Just curious but has anyone bought stuff from the website: www.govliquidation.com I just started looking at it last night, they have a ton of stuff and right now everything has zero bids. I don't know if people all snipe at the last second or what. Thoughts / Opinions? Jason Jason, No snipe allowed... if you bid the expiry time is prolonged. Any kind of bad stories; you must be there and see the equipment and remove it personally, or you get a lot of scrap. At least, this is true buying from Europe! Too many people involved, misdescriptions, extremely bad packaging, and so on. I bought four or five times years ago, then I had enough. The European office was managed by good people, but unable to help. Now it's closed. 73 - Marco IK1ODO Bidding on the TM equipment doesn't open until tomorrow. And most of it is export restricted - it is only available for domestic sale so those of use anywhere else have to wait for the dealers to get hold of it and make their teensy weensy little bit of profit. John ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] The Shadow Knows
At 03:03 PM 1/25/2007, Hal Murray wrote: Best line: Toward the end of 1986, Atwood curtailed the museum's collecting and publishing activities. Seth Atwood is the only person I know who was infected by the horological virus and later recovered, Andrewes says. For most collectors, death is the only cure. Oh how true! I can't afford to be a collector, but even an interest in time rapidly becomes and obsession and then you are on the slippery p[ath to addiction. I have never heard of time-nuts anonymous, and I hope I never do. John ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] Loran-C ICs
Funny you should ask, we had to get some of these to replenish spares stock in a client site for some gear we built YEARS ago. The MC1357P is available as the NTE708 (around $7.25 each it seems) and the MC1350P is an NTE746. The next generation of that design (the MC1350P as okay in TV's, but really not a lot of good elsewhere) used some VGA chips from Analog Devices, AD6xx series, but I cannot recall which. Possibly AD602. We used one of the AD log detectors, possibly like an AD8302 to complete the AGC loop. In another design we had the FM demodulator in an FPGA and we recovered amplitude information after the ADC to close the AGC loop - we need not have rapidly varying signals, and then used another small 10 bit ADC to control the IF amp chip. John At 04:56 PM 1/2/2007, you wrote: Hi Poul: I'm trying to make a micro controller based unit, not a PC type. So there's much less horsepower available. That's why I like the envelope detector by Burhans. An email from Dave Mills indicated that you had one of his ISA card receivers but that a 12 bit PCI version would be better. Have Fun, Brooke Clarke w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com Poul-Henning Kamp wrote: In message [EMAIL PROTECTED], Brooke Clarke writes: Hi: I found a Loran-C circuit from 1984 done by Ralph Burhans that uses the MC1350 Video-IF amplifier and the MC1357 Sound-IF amp and Quadrature detector, but these are no longer available. Does anyone know of replacement parts? The circuit appears in Low-Frequency Receiving Techniques, Building and Using VLF Antennas a Gernsback publication. Don't bother. You will get much better results by putting an A/D converter on the signal and spending a bit of CPU power. (see http://phk.freebsd.dk/loran-c for inspiration) ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] Loran-C ICs
At 07:45 PM 1/2/2007, John Miles wrote: The SA604AD is a favorite of mine, if you need a good IF strip with a quadrature detector. Have to agree. Only ever used them in three designs but two of them went into quite high volume back in the late-80's/early-90's and they were never a problem. To be honest, I had forgotten about them. We moved from the MC1357 to the NE604 (as it was then) and then to DSP for FM demodulation. John You can still get MC1350Ps from Jameco, but the 1357 is relatively rare (except, as John points out, as an NTE replacement.) -- john, KE5FX -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of John Day Sent: Tuesday, January 02, 2007 4:40 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Loran-C ICs Funny you should ask, we had to get some of these to replenish spares stock in a client site for some gear we built YEARS ago. The MC1357P is available as the NTE708 (around $7.25 each it seems) and the MC1350P is an NTE746. The next generation of that design (the MC1350P as okay in TV's, but really not a lot of good elsewhere) used some VGA chips from Analog Devices, AD6xx series, but I cannot recall which. Possibly AD602. We used one of the AD log detectors, possibly like an AD8302 to complete the AGC loop. In another design we had the FM demodulator in an FPGA and we recovered amplitude information after the ADC to close the AGC loop - we need not have rapidly varying signals, and then used another small 10 bit ADC to control the IF amp chip. John ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] Shopping list
Funny you should ask because I have one of those and no manual either! John At 01:54 PM 8/21/2006, you wrote: Hi! I just went to the store to shop, my shopping list ended up being: 2 l of milk 1 l of orange juice 1 pkg of fresh pasta willed with cheese and yes... I'll have that HP J06-59992A Time Interval Calibrator :-) When you pickup your packages in the store, this is what you get. :-) Aaanyway, beyond my foodhabits, the calibrator is used for HP5370, HP5371 and HP5372. It is a fancy waveshaper of sorts, but it helps to calibrate out the systematic offsets in the input circuits. This is needed to get increased accuracy when averaging. Naturally, it's all covered in a HP patent. ;O) It has 4 big and 1 small button on the front, 2 LEDs and a 7 position DIP switch on the back, 4 BNCs, power outlet and a HP-IB connector. Not alot of functionality for a HP-IB connector, but it sure helps to automate things. Now, does anybody has a manual or even service manual for this piece? Cheers, Magnus ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] Shopping list
At 11:48 PM 8/21/2006, you wrote: On the HP J06-59992A Time Interval Calibrator, have either of you opened it and taken a look inside? It's quite simple. No, it's been sitting in my basement unused for, oh don't ask how long! The digital half is a generic GPIB board. The RF half is just a couple of MCL splitters and TO5 RF relays. I'll look for my manual if no one else has one handy. But you can trace the RF path in a few minutes... Now I have a question for any HP old-timers our there. What's with the H05 and J06 and K20-looking prefixes that we see from time to time on special-purpose HP gear? And for extra credit, what the magic 59992A part number? This shows up in more places than this calibrator. I must admit I never asked this one. But I do recall seeing 59992A model numbers in a number of systems that I used to use from HP. J06 - Time interval calibrator K10 - battery backup K38 - video amplifier K87 - a video amp plug-in for the 5345A The H06-59992A calibrator is called out as recently as the 53131A/53132A counters in the calibration procedure. John /tvb ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] HP 5370A manual
At 05:29 PM 7/25/2006, you wrote: I have been looking for the operation/service manual for my HP 5370A for some time. I had previously found the B manual online. Just recently, I found the A manual at this URL: http://www.g8wrb.org/data/HP/ It can also be found at http://nm2.org/files/HP5370A.pdf John You should also find it on the Agilent site soon, as I sent them the link. ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] HP 3325B Function Generator and GPS based frequencycontrol
At 05:14 AM 7/12/2006, you wrote: I agree with that. I have an HP 3586A Selective Voltmeter and it has the LO output on the rear which covers 0-32 MHz. I wish there was a programmable attenuator on this output as it is exceptionally clean spectrally. Of course, there is no modulation capability. What about a 3336(A, B, C)? Although the attenuator is only on the 21MHz output, but if you can get one with option 5 it is a beautiful low noise modulatable source with an outstanding attenuator. John Didier KO4BB Magnus Danielson wrote: ... The only thing which annoys me is that it doesn't go higher in frequency and that I wish I could run the modulation source internally even if I like the contacts at the back. If you don't get the modulation source to do anything reasnoble, check if you have hooked up a cable! Cheers, Magnus ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] HP 58540A Phase Noise Improvements
You're right Matt. The basic PN performance of the LO chain in the IC-7800 is not too good. Measurememnts of the IMDR confirm this. So I personally think looking for a lower phase noise OCXO would be a fruitless exercise. It would be far more valuable to figure out what features of the design of the 7800 contribute to the problem. The IC7800 is a 'strong' receiver in terms of IP3 and IP2 - one of the best in ham terms, but I am not sure that without drastic internal surgery you are going to do any better. Of course, if someone would like to send me an IC7800 I would be happy to experiment on it! John At 01:19 PM 7/7/2006, Matt Ettus wrote: Does anyone have any suggestions as a replacement OCXO with excellent phase noise approaching -160 dBc @ 1 kHz? Are there any special precautions or other alignments required when dropping in a replacement OCXO? Thanks! Paul, It is very likely that the close-in phase noise of the ICOM is determined more by the dividers in the PLL than by the phase noise of the reference oscillator, especially at such low levels. Assuming that the ICOM divides the 10 MHz down to at least 100 kHz, the phase noise of the OCXO would be divided down to -200 dBc, which is well below the internal divider noise of the PLL. Thus even an OCXO with absolutely no phase noise would not improve things. Matt ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] questions on uncompensated crystal oscillators
At 02:48 AM 7/5/2006, [EMAIL PROTECTED] wrote: In a message dated 7/4/2006 09:52:33 Pacific Daylight Time, [EMAIL PROTECTED] writes: Hello, Please excuse the fact that this is not what we all consider precise frequency. I am selecting crystals to use for a medium to high volume application. The basic criterion are: - used with a VLSI inverter based oscillator with 3.3 V supply, but somewhat high impedance output. - frequency: 27.000 MHz fundamental within 40 (or so) ppm over temperature including 7 to 10 years of aging. - HC49S case - no production line trimming - low cost After looking at the design issues, I wonder if some of you haven't faced similar designs and have some suggestions regarding the following issues: Hi Stan, I have designed a circuit that does exactly this, and published it in EDN. See page 92 for the article: _http://www.edn.com/contents/images/112703di.pdf_ (http://www.edn.com/contents/images/112703di.pdf) It's a VCXO 27/32MHz reference for a Video Decoder. You can delete the Varicaps if you don't need it to be adjustable. BTW: The crystals and inverter used in the design are quite good, the circuit generates less than 3ps jitter (measured on a Wavecrest SIA-3000) - jitter is really what counts in digital timing for video etc. Some caveats to watch out for: * for NTSC you can have up to about +-840Hz deviation and still be within limits. * Don't overdrive your crystal (see manufacturers spec) otherwise it can age too fast, and get damaged. Typically, use about 100uW or so. Measure the current into the crystal using a fast AC current probe * Make sure you have enough gain to guarantee startup (the circuit should work with at least 3x series resistance as will be used in production). This will mostly depend on the crystal ESR (should be as low as possible), while still not overstressing the crystal * 10ppm crystals are very(!) expensive, rather use trimming during production testing by removing/adding load cap options. This allows you to use a cheaper crystal (with a higher ppm rating), and spend more money on lower thermal susceptability specs. Hope this helps, bye, Said I would agree with you Said, 10ppm is a lot to ask and let's be honest, production trimming is not so difficult these days. Without going to 10ppm you can get your crystal manufacturer to group your crystals by cut angle. This will give you a basic temperature coefficient curve - for a given angle the tempco curves are quite similar. We used to do this with fundamental mode crystals at between 12 and 20MHz. You can then have a set of compensation tables and drive the varicaps from a DAC to keep the crystal under control. I have done this using small micro's, like the Zilog Z8, or using a bit of really crude ADC-Table-DAC circuitry in an FPGA and it works quite well. This was done to avoid having to use TCXO's in SCADA/DATA type radios. For higher performance equipment we used to have the compensation table built by the test system during temperature cycling. John ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] NPL Time Frequency Club Meeting
Rob, It happens I will be in the UK that week, but I am not sure my 6 year old daughter would be welcome! I have bookmarked the site and will keep a watch on it because it may be that a future trip could coincide with a meeting, thanks for the post. John At 03:35 AM 7/4/2006, you wrote: NPL (National Physical Laboratory) Time Frequency Club hold their next meeting on 14th September at NPL Teddington. The meeting is free to all, but you need to register. Please see www.npl.co.uk/time/club for more details, and a registration form. Rob Kimberley ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] [hp_agilent_equipment] 5371A CRT problem
Oops! sorry fr the reply-all folks, resulted in a cross-post! Steve, The CRT controller in the 5371A is a stock standard Motorola MC6845P, the timing is discussed in the theory of operation section and it seems there is nothing more than two sync signals and a three level video signal that goes to the CRT assembly. John ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] 5371A CRT problem
New CRT's for many of that era of HP instrument can be had pretty economically too. If the raster moves around rather jerkily then give the unit a good suck out with a vacumn cleaner! Use a nice clean dry toothbrush to look for collected gunge particularly around the spark gaps on the CRT socket board and the yoke assembly. These problems are not uncommon in things like the 8920's and the like. John At 01:05 PM 6/23/2006, you wrote: Hi Steve, I have a 72A and was wondering about the same thing. My unit works well, but the display looks weak. The raster moves around sometimes. If the CRT itself is bad, those can be had used from various surplus tube dealers at probably not too big a hit. There is a blanking control that hides the screen and blanks it for security purposes. Did you enable that? Check. Doug K6JEY. At 09:50 AM 6/23/2006, you wrote: After a few weeks of inactivity, I recently powered up my HP 5371A and discovered the display is not working. Everything else is working, and I can print the results that normally appear on-screen. I've checked the supply voltages to the CRT driver card A17, and the horizontal sync, vertical sync, and video signals are all present going into A17. I can see the CRT filament glowing. Next step is to check the CRT anode voltage, and the deflection signals at the CRT pins. Does anyone have an idea what they should be? The service manual skips any circuit description or schematic of A17 and says if the CRT circuits are suspect, replace the A17 CRT Driver Board and CRT as an assembly. That assembly is no longer available, and would certainly not have been available at a hobbyist price at any rate. If I can't come up with a schematic, my choices are to look for a parts unit, or bite the bullet and go GPIB. Does anyone know of a parts unit available? Thanks, Steve, WBÃDBS ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] HP-5245L Parts
At 04:18 PM 5/24/2006, Allan W. Bart, Jr. wrote: These units are still plentiful, you might want to go to a local hamfest or ebay, the better deals are at the hamfests. Allan The side frames are common to many instruments of the period. Some power supply parts are common to the 5246, 5245 and 5248 (the 5246 is a skun down 5245, the 5248 goes to 150MHz as I recall). The 5245L suffers for frequency comparison because it has only a period average (no Time Interval Average) and the period average is only good to 300kHz. The 5262A doesn't support averaging either, so it or the 5263A (same case I think) will only offer resolution of 100ns. The 5345A will offer 2ns single shot time interval resolution and can average over 1000 intervals giving 2ps resolution. The ideal is the 5370A/B which has a single shot TI resolution of 20ps. John From: Bruce Lanning [EMAIL PROTECTED] Date: Wed May 24 14:33:17 CDT 2006 To: Discussion of precise time and frequency measurement time-nuts@febo.com Subject: Re: [time-nuts] HP-5245L Parts Thanks Allan for the response. I have the HP-5245L and the HP-5262A Time Interval Unit, but it is not working. Problems in the PS and the front handle on the right side is broken off. I had planned to use this unit for frequency comparison, but not sure this is what I want. Your comments would be appreciated. Bruce W1GBS - Original Message - From: Allan W. Bart, Jr. [EMAIL PROTECTED] To: Discussion of precise time and frequency measurement time-nuts@febo.com Sent: Wednesday, May 24, 2006 2:22 PM Subject: Re: [time-nuts] HP-5245L Parts Hello, I have one of these units and it will never die, try fair radio in Lima OH. Allan Bart From: Bruce Lanning [EMAIL PROTECTED] Date: Wed May 24 12:55:58 CDT 2006 To: time-nuts@febo.com Subject: [time-nuts] HP-5245L Parts Looking to buy a HP-5245 or equivalent for parts only. Need not be working, or complete. If you have this animal and would be willing to part with it, please contact me directly at: [EMAIL PROTECTED] Thanks, Bruce W1GBS in Maine ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] Entry level systems
At 06:31 PM 5/24/2006, John Ackermann N8UR wrote: Keith E. Brandt, M.D. said the following on 05/24/2006 06:06 PM: What's a good entry-level time reference system? I'm doing this for the fun/learning/hobby and can't dump $10k into it (without also incurring the attendant lawyer's fee for the divorce settlement :-) I think something along the lines of the TAPR TAC would be perfect if they still made it. Are there other relatively low-cost GPS reference systems out there? Interesting question! Assuming you mainly want to have a test-bed for learning and experimentation, I'd say you want three things: 1) a local frequency standard, 2) a frequency/time interval counter, and 3) a GPS or other radio reference. For the frequency standard, one of the surplus HP 10811A or 10544A oven crystal oscillators (OCXO) which can be had on eBay for $50 - $150 would be good, or one of the surplus Efratom Rubidium standards that go for the $250 range -- each has its own advantages; the crystal will have better short term stability and less phase noise, but the Rb will have better long term stability and will need to be recalibrated far less often. You will often find that it is cheaper to buy a counter with the high-stab oven option than to buy the oven separately. For the frequency counter/time interval counter, I am very partial to the HP 5334A or B. They are quite cheap on eBay (usually less than $150 and have 2ns time interval resolution. As a bonus, many of them have the high-stability option (001) that includes an HP 10811A oscillator, and if you find one with the channel C option you will be able to read frequency to 1.3GHz. The 5335A is also sold from about $100 up and has the oven option as opt010, 1.3GHz is opt030 and opt040 - expanded HPIB control is worth having if you plan to remote the counter at all. A little heavier is the 5345A which can be equipped for operation all the way to 40GHz or so at not a huge expense. It is one of my all time favourites. It has 2ns resolution and counts direct to 500MHz. They came as standard with the high stab oven, opt001 removes the oven. Opt010 is very basic HPIB talk only, opt011 HPIB with remote programming, opt012 is HPIB like 011 but has control of slope and trigger level as well. You can pay from $80 or so for basic counter with HPIB. Just get the seller to confirm it is not Opt 001! The 5345 is heavy, and a bit noisier than the newer 5334A/B or 5335A. To my m ind if you are interested in frequerncy measurement, this counter can give you flexibility well beyond anything else that mere mortals can afford when coupled with various plug-ins and convertor heads. 73's, John (ex VK3ZJF) Finally for the GPS. We're in a state of flux right now because Motorola sold their line of GPS receivers and the one everyone would have recommended last year is no longer available. Nonetheless, you may be able to find an M12+T receiver which is the best unit they had available, or the slightly older UT+. You'll need an antenna, but you don't necessarily need the TAC-2 -- all it really does is provide power supply and I/O buffering. You can do that on a piece of perfboard if you want. There are lots of other neat toys, but with those three you'll have a good frequency standard and a way to calibrate it. Hope this helps. 73, John ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] Interesting Patent
No, I have a HP 521C which comes with the HP 521A-59B crystal oscillator plugin module, but the HP 521A has it as an option. The HP 521C also have an additional counting row and an additional step in the timebase. Actually, you can supply it with an external time base of any of the frequencies 10, 20, 30, 40, 50, 60, 70, 80, 90 or 100 cps. The service manual is available on BAMA, I did the DJVU formating. A 521C, wow, I don't have any data handy but it goes to what, 100kHz? My first counter was a 524B as I recall - the plug-in version of the 524A. It still had the column of neons indicators, but I can recall if it had the meters at the top end. Eventually I got a 524C (or D?) and a selection of plug-ins. I had a couple of video amplifier plug-ins and ripped the guts out of one to put a 150MHz prescaler in there as I recall. I was playing a lot with 10-12GHz at the time and I had a 540B transfer oscillator as well. That and the 851/8551B spectrum analyser ensured that I had a well warmed, and very noisy, lab. Hmm... (looking in HP540B manual), must have been lovely in its time. It was, but you realise now just how much work we had to do to measure anything! After using the 540B, the 5257 seemed a delight, then the 5345/5355/5356 combination we were suddenly freed from having to adjust anything. For some reason I never had a 5340 which would have been nice in its day. Of course the 851/8551 analyser was another challenge. You always had to keep a camera swinging from the tube escutcheon because your display would be what you wanted for such a little time! Good that you where warm and awake... :P Eventually I got a 5245L and a Dymec 2590B which was supplanted for my uses when I got the 5257 (I think it was, 18GHz transfer oscillator). A 431C and a 434A along with the 600 series monstrous klystron generators rounded out the lab.. It was truly wonderful when the 141T system, the 5345A and the 432C came along! Especially with the 8600 generators including of course the 8640B. Thanks for the reminiscences guys! Theres a journey. So far I keep quite low frequencies. I can hit 2 GHz with my current rig, 1.3 GHz until I got my latest counter. I don't fool around at such high frequencies... or wait... I just realize that I do :P Haven't worked in microwaves since 1999. In fact sold all of my personal gear - I can generate up to 1.3GHz, count to 350MHz and analyse up to 40MHz these days. The real difference was in my last job. I was working on 23/24GHz link designs and we had an 8563 or 64 with the 26.5GHz tracking generator. A Gigatronics synth and a 438 power meter. And that was all! Even more unrealistic was that was all we needed! I could have fit all the gear in the trunk of my car and taken it home. How things changed over that period. John Cheers, Magnus ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] Interesting Patent
Good suggestion Dave. It would be nice just to see some of that gear again! Of course, you need a darned good air conditioner if you are going to use any of it. John At 05:31 PM 5/16/2006, you wrote: Looking to get good colour photos of some of these older HP counters (and similar offerings from other manufacturers) in the pre/early Nixie etc period. If you have anything available would appreciate direct email of same. Thanks Dave Brown, NZ ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
[time-nuts] OnCore R5122U1112 modules
On the basis of Randy's comments I purchased a couple of these receivers. Although I have a long and abiding interest in time, I have not had anything more precise than the kitchen clock since 1996 (when I sold my calibration lab) unless you count the Efratom Rb module which has followed me around the world these last 10 years but which hasn't seen power since then either! Now my friends chide for me being able to tell them all about time, but not being able to tell them the time. So I have built two clock displays, one using a small CRT and the other using a small colour LCD. Both are being driven from 10pps (pick a number, any number) derived from the thing called a reference in my Tektronix DC5010 counter. My questions: What sort of antenna do I need for this receiver? Where do I get manuals? John ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] GPS Selective Availability. Is it On or Off?
Well, thanks for the offer! I am happy to put any manuals there - I own the server and it sits in a rather large data-centre with a HUGE fat pipe! However, I haven't made any provision for uploading. I am a little hesitant as I could get all sorts of undesirable material uploaded and clogging up my drives. If you have something you want to post you can email it to me (I can receive unlimited attachment size, remember, I own the server!) Or drop me a line and we can arrange to get it and upload it. As a matter of interest, last month we served up 40.235gb of data from nm2.org, up from 29gb in March and 7.48gb in February. The previous high was 24.43gb in December 2005. You can reach me at: johnday #AT# wordsnimages #DOT# com John At 10:20 PM 5/3/2006, Normand Martel wrote: Wow!!! By simple curiosity (I heard somewhere that curiosity was a sign of intelligence... ;-) ) i went to the URL link... I discovered a real treasure on this site! MANY Hewlett-Packard/Agilent manual PDF's available!!! Thanks a lot! How can i upload HP/Agt manuals if i find some? I would be happy to contribute. Have a good day! Normand Martel Montreal, Qc. Canada Robs briefing file saasm coml brfg 7-04.pdf (very interesting actually!) can now be found at: http://nm2.org/files/saasm coml brfg 7-04.pdf Anyone else in the group with files or manuals that need hosting can let me know and I will put the files there. The only thing at nm2.org right now is files and manuals for this group and the hp-agilent equipment group. Last month a mere 2.2gb of data was transferred, which is in fact only about 1% of the transfers on that particular machine - so I am quite happy to maintain it. Since June 2005 when I started hosting the manuals there has been 43,602 completed downloads from over 130,000 hits from 4672 distinct visitors. Total downloads in that time is just over 125gig. __ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] time-nuts Digest, Vol 21, Issue 22
So Loran isn't really dead yet! John At 03:34 AM 4/20/2006, you wrote: The current definition of the second is based on Caesium, as that was what was the best then. However, with work on the newer optical standards, and Rubidium Fountains, I'm pretty certain that in the next few years the second will be re-defined. Attached document from UK national Physical Laboratory (NPL) may be of interest. Rob K -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Tom Clark, K3IO (ex W3IWI) Sent: 20 April 2006 06:59 To: time-nuts@febo.com Subject: Re: [time-nuts] time-nuts Digest, Vol 21, Issue 22 VE2VM commented But Isn't Cesium drift-free? Since the SI second is standardized as de duration of 9192631770 oscillation of the hyperfine transition of the atom 133Cs? If Cesium drifts, theren should be a more formal definition of the second (Such as density, maximum C-field or level of purity). Does anyone here has it? The achieved frequency can be pulled by external factors. The official SI second definition is 9,192,631,770 cycles of the ground-state hyperfine splitting of the unperturbed cesium atom. The problem is making it be unperturbed by the effects of the finite microwave cavity, wall effects from the containment bulb, the length of time that the Cesium atom is stored in its excited state, etc. A good recent review is the paper by Diddams (Science, November 2004) available from the NIST web site at [1]http://tf.nist.gov/timefreq/general/generalpubs.htm Getting the cesium atom unperturbed has led to larger and longer Cesium standards at NIST (for pictures see [2]http://tf.nist.gov/cesium/atomichistory.htm); with the longest of the Cs tubes (NIST-7), the interaction time (the length of time the Cesium atoms live in their excited state is ~10 msec. The newest generation of Cesium fountain clocks use Laser cooling to contain a cloud of cesium atoms at at temperature near 0º Kelvin to minimize the wall effects and to increase the storage time to ~1 second (see [3]http://tf.nist.gov/cesium/fountain.htm and [4]http://tycho.usno.navy.mil/clockdev/cesium.html). And also, something else i don't understand: Why do the newer GPS satellites rely on Rb standards rather than Cs standards? Since Rubidium is known as less precise than cesium? Is there a reliability issue there (Rb clocks are more reliable / longer MTBF tha Cesium clocks). I don't know... The Cesium clocks in GPS have been less reliable (probably because they are more complicated) than the Rb clocks in early GPS satellites; [5]for some information see the FAQ on this USAF web site. The 16 Boeing Block II IIA satellites have 2 Cs and 2 Rb. The 7 LockMart (your One-Stop Defense Contractor!) Block IIR satellites launched (plus 8 more awaiting launch) have 3 Rb. The Rb/Cs mix will change will change again with the IIF 3rd generation GPS satellites ([6]see Symmetricom propaganda here) and with the European Galileo series (Galileo is planning on H-Masers). There is an interesting article in [7]The Space Review on the clocks planned for these next generation navigation spacecraft. 73, Tom References 1. http://tf.nist.gov/timefreq/general/generalpubs.htm 2. http://tf.nist.gov/cesium/atomichistory.htm 3. http://tf.nist.gov/cesium/fountain.htm 4. http://tycho.usno.navy.mil/clockdev/cesium.html 5. http://gps.losangeles.af.mil/jpo/gpsoverview.htm 6. http://www.symmsda.com/about_us/index.asp 7. http://www.thespacereview.com/article/534/1 ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] Loran-C Austron
Austron was a Datum Company, so I assume it is now Symmetricon? John At 05:45 PM 4/20/2006, you wrote: Hi Rob: What happened to Austron? Brooke Clarke, N6GCE -- w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com Rob Kimberley wrote: No, LORAN is most definitely not dead. Good news, as I used to sell LORAN-C timing from Austron back in the 80's. Worked well then, and works well now. Rob K -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of John Day Sent: 20 April 2006 20:21 To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] time-nuts Digest, Vol 21, Issue 22 So Loran isn't really dead yet! John ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] eBay and oven oscillators
Just look again next week! Ebay is an amazing movable feast of stuff. No, I don't think we are driving prices up, down or sideways. But ebay isn't DigiKey, you can get anything you want - but maybe not today. Also think laterally. A few months ago I needed something like an HP 10811 10MHz oscillator, at the time they were going for near $100, so I bought a 5328 counter with the high stab option for $27, pulled the module out and sold the carcass for $15 for parts. Keep hunting, you will find them. Jon At 08:20 AM 4/7/2006, you wrote: I just bought an ovenized 5MHz oscillator (24V unfortunately) for I think $9??? Didier KO4BB Rex wrote: Just curious if you time-nuts are driving prices up. A year or more back I was shopping for some 5 or 10 MHz ovenized oscillators. 12V or less for input was a desirable feature. I found a few at not too bad prices. Tonight, I decided to have a look and see if I could find some more. Well there are a few listed. Most are only from buy it now sellers. Nothing looked interesting at the features or prices asked. Is my timing (no pun) just bad or have the good deals all been eaten by eBay pro money grabbers? Are there any good deals left for basic crystal source devices? Maybe I have to shop for messed up test equipment that I know has good timing references in them? ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] GPS Selective Availability. Is it On or Off?
Robs briefing file saasm coml brfg 7-04.pdf (very interesting actually!) can now be found at: http://nm2.org/files/saasm coml brfg 7-04.pdf Anyone else in the group with files or manuals that need hosting can let me know and I will put the files there. The only thing at nm2.org right now is files and manuals for this group and the hp-agilent equipment group. Last month a mere 2.2gb of data was transferred, which is in fact only about 1% of the transfers on that particular machine - so I am quite happy to maintain it. Since June 2005 when I started hosting the manuals there has been 43,602 completed downloads from over 130,000 hits from 4672 distinct visitors. Total downloads in that time is just over 125gig. John At 02:54 PM 3/14/2006, Rob Kimberley wrote: I have a 75 page PDF briefing from Zyfer on SAASM P/Y which has loads of useful information on GPS signal structure, acquisition, jamming, spoofing etc. Can either post it to the group (approx 3MB) or send it on request. Rob Kimberley ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] OSA 8600 BVA oscillator
Boîtier à Vieillissement Amélioré :) At 04:42 PM 3/15/2006, you wrote: Dear Gentlemen Many thanks for your great interest and the many bids on the OSA 8600 BVA oscillators. Few minutes ago I made the decision and sold the three units. It seems that some of you are aware of the BVA resonator high end technology. May be that some attended the 1976 or 1983 Frequency Control Symposium at Fort Monmouth when Raymond Besson and Erhart Graf introduced the advantages of the new electrodeless crystals. Do you for what the abriviation exactly stands for ? Kind regards Hans ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] GPS Selective Availability. Is it On or Off?
If you send a copy to me I can post it at nm2.org for anyone to access. john At 04:36 AM 3/14/2006, you wrote: I have a 75 page PDF briefing from Zyfer on SAASM P/Y which has loads of useful information on GPS signal structure, acquisition, jamming, spoofing etc. Can either post it to the group (approx 3MB) or send it on request. Rob Kimberley -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Magnus Danielson Sent: 13 March 2006 22:32 To: [EMAIL PROTECTED]; time-nuts@febo.com Subject: Re: [time-nuts] GPS Selective Availability. Is it On or Off? From: Tom Clark, K3IO (ex W3IWI) [EMAIL PROTECTED] Subject: Re: [time-nuts] GPS Selective Availability. Is it On or Off? Date: Mon, 13 Mar 2006 16:44:51 -0500 Message-ID: [EMAIL PROTECTED] Chuck said I got the notion that it was turned off during Desert Storm, by virtue of being involved in the e-warfare effort that lead up to, and followed the event. I haven't been paying much attention since. I knew that they had intended to turn SA back on after production of the p-code units was up to speed, but I hadn't heard whether or not they did. Yes, it was turned off for a brief period during DS, largely because the DoD had to scurry around to buy mortal commercial units to fill the need. Also during DS (and the present excursion) lots of parents sent COTS GPS widgets to their kids. It turned out that one of the most important uses of cheap GPS receiver in DS was by the food trucks. Troops were deployed in the desert all along the Iraq Kuwait border. The mess tents were behind the lines, and hot meals needed to be delivered to the remote outposts. The delivery trucks found they could navigate across the roadless desert very well by using GPS receiver intended for navigating civilian boats. S/A is a dithering of the clock with a pseudorandom phase jitter. The key to disentangling it was to have the same code generator available on the ground. I use the analogy that DoD had a smart mouse in each satellite running around on a phase resolver. To de-jitter it, you need the mouse's clone inside the receiver. The dithering of S/A had nothing to do with the encryption of the P code to make the Y code. The P-code is a LOG code (37 weeks until a repeat) at 10.23 Mbits/sec. Each of the satellites uses the same code stream, offset by some integer number of weeks. The Y-code is an additional secret code that uses a shorter code to (pseudo)randomly flip the phase of the P-code. On the ground, the civilian code crackers have found out that the convolution code is running at a rate ~500 kbits/sec. This means that the Y-code may be the correct P-code for ~20 bits, and then it (may|may not) flip phase to become anti-P code. AFAIK, Ashtec's patented Z-code receivers generate a hardware estimate of this code and (nearly) coherently demodulate the signal. Other brands have similar tricks up their sleeve. The Y-code is the P-code xored with the A-code (sometimes also referred to as the W-code). The A-code is indeed ~500 kbis/sec. The first codeless receivers just squared out the A-code from the equation, but then they had a worse problem to fight regarding ambiguity. Also, it does not form a very good receiver. The Ashtec solution is to make the L1 handover from C/A-code to P-code and predict the A-code, delay that a suitable amount to the L2 Y-code and attempt to lock up to that. The delay is trimmed to match up with the L1-L2 delay in P(Y)-code. You could say that the Ashtec receivers cracks the code, but they really don't since they do not disclose the state of the A-code generator or its architecture. Infact, they don't even get it rigth all the time, but sufficiently often for a good lock since each success has a good quality. It is interesting that what they did to figure things out was hunting GPS satellites with a big parabol antenna tracking the satellite and getting a much better S/N than normal semi-omnidirectional antennas. With that they could make advanced guesses. Cheers, Magnus ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] GPS Selective Availability. Is it On or Off?
[EMAIL PROTECTED] At 02:54 PM 3/14/2006, you wrote: John, What email address do you want me to send to? Rob -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of John Day Sent: 14 March 2006 18:34 To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] GPS Selective Availability. Is it On or Off? If you send a copy to me I can post it at nm2.org for anyone to access. john At 04:36 AM 3/14/2006, you wrote: I have a 75 page PDF briefing from Zyfer on SAASM P/Y which has loads of useful information on GPS signal structure, acquisition, jamming, spoofing etc. Can either post it to the group (approx 3MB) or send it on request. Rob Kimberley -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Magnus Danielson Sent: 13 March 2006 22:32 To: [EMAIL PROTECTED]; time-nuts@febo.com Subject: Re: [time-nuts] GPS Selective Availability. Is it On or Off? From: Tom Clark, K3IO (ex W3IWI) [EMAIL PROTECTED] Subject: Re: [time-nuts] GPS Selective Availability. Is it On or Off? Date: Mon, 13 Mar 2006 16:44:51 -0500 Message-ID: [EMAIL PROTECTED] Chuck said I got the notion that it was turned off during Desert Storm, by virtue of being involved in the e-warfare effort that lead up to, and followed the event. I haven't been paying much attention since. I knew that they had intended to turn SA back on after production of the p-code units was up to speed, but I hadn't heard whether or not they did. Yes, it was turned off for a brief period during DS, largely because the DoD had to scurry around to buy mortal commercial units to fill the need. Also during DS (and the present excursion) lots of parents sent COTS GPS widgets to their kids. It turned out that one of the most important uses of cheap GPS receiver in DS was by the food trucks. Troops were deployed in the desert all along the Iraq Kuwait border. The mess tents were behind the lines, and hot meals needed to be delivered to the remote outposts. The delivery trucks found they could navigate across the roadless desert very well by using GPS receiver intended for navigating civilian boats. S/A is a dithering of the clock with a pseudorandom phase jitter. The key to disentangling it was to have the same code generator available on the ground. I use the analogy that DoD had a smart mouse in each satellite running around on a phase resolver. To de-jitter it, you need the mouse's clone inside the receiver. The dithering of S/A had nothing to do with the encryption of the P code to make the Y code. The P-code is a LOG code (37 weeks until a repeat) at 10.23 Mbits/sec. Each of the satellites uses the same code stream, offset by some integer number of weeks. The Y-code is an additional secret code that uses a shorter code to (pseudo)randomly flip the phase of the P-code. On the ground, the civilian code crackers have found out that the convolution code is running at a rate ~500 kbits/sec. This means that the Y-code may be the correct P-code for ~20 bits, and then it (may|may not) flip phase to become anti-P code. AFAIK, Ashtec's patented Z-code receivers generate a hardware estimate of this code and (nearly) coherently demodulate the signal. Other brands have similar tricks up their sleeve. The Y-code is the P-code xored with the A-code (sometimes also referred to as the W-code). The A-code is indeed ~500 kbis/sec. The first codeless receivers just squared out the A-code from the equation, but then they had a worse problem to fight regarding ambiguity. Also, it does not form a very good receiver. The Ashtec solution is to make the L1 handover from C/A-code to P-code and predict the A-code, delay that a suitable amount to the L2 Y-code and attempt to lock up to that. The delay is trimmed to match up with the L1-L2 delay in P(Y)-code. You could say that the Ashtec receivers cracks the code, but they really don't since they do not disclose the state of the A-code generator or its architecture. Infact, they don't even get it rigth all the time, but sufficiently often for a good lock since each success has a good quality. It is interesting that what they did to figure things out was hunting GPS satellites with a big parabol antenna tracking the satellite and getting a much better S/N than normal semi-omnidirectional antennas. With that they could make advanced guesses. Cheers, Magnus ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com
[time-nuts] OT magazine scanning
I think I have seen this topic discussed here some time ago. I have been receiving RF Design magazine for some years and I no longer have space for them. They are not available on CD-ROM, so maybe somebody here knows of a scanning service that could handle a job like this? I am happy to sacrifice the mags to save the space, so they can be cut to separate the pages. Any clues anybody? John ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] OT magazine scanning
At 03:01 PM 3/3/2006, you wrote: Hi John: My local copy center will digitize, but they have different fees depending on what the source material is. Black and white text, line drawing, color photo, etc. Have you checked with RF Design to see if they have digital versions of back issues? Yes, I did, and unfortunately the answer was no. I will check the local copy places, but most of the ones around here want you to give them an original so they can watch the Documation or whatever spit out 5,000 copies while they chew gum. I have converted a number of manuals into pdf documents and can say that it's quite a bit of work to get a really useful result. Oh don't I know it, particularly with fold-outs, I have done far too many of those. That is why I am hoping to find a service to do this job. 73's John 73, Brooke Clarke, N6GCE -- w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com John Day wrote: I think I have seen this topic discussed here some time ago. I have been receiving RF Design magazine for some years and I no longer have space for them. They are not available on CD-ROM, so maybe somebody here knows of a scanning service that could handle a job like this? I am happy to sacrifice the mags to save the space, so they can be cut to separate the pages. Any clues anybody? John ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] Interesting eBay-item?
Back about 1986 or 1987 HP produced three prototype Mercury trapped ion standards for the USNO. I don't know if they built any others. This listing shows just one rack, I cannot recall if it was these units or a Maser prototype built by HP that was actually in two racks. Several papers appeared in the mid-90's talking about the experience of the USNO with these over 8 or 10 years. John At 11:51 AM 2/2/2006, Christoffer Bruman wrote: Dear List, perhaps this item could be of interest to some fellow time-nut?: http://cgi.ebay.com/Mercury-Ion-Frequency-Standard-Set_W0QQitemZ7586640474QQcategoryZ25399QQrdZ1QQcmdZViewItem If the link does not work, its eBay item 7586640474. And no, I have no connection to the seller or the item, I just found it interesting since I have never heard of HP manufacturing such a system.) From the look of it, and some of the HP part numbers, it has a very custom/one-off feel about it. Perhaps anyone on the list has any details? Best regards, Christoffer Bruman (wannabe time-nut, still excited from winning a good 10811 from eBay...) Sweden ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] Mirrors for HP 5370B time-inteveral counter manual
Number 2 is in Toronto, Canada - right in the main carrier hotel downtown with excellent bandwidth. At 06:08 PM 12/30/2005, you wrote: A number of people have offered to host the 600 dpi scanned manual for the HP 5270B time interval counter, which I can no longer host due to disk space limitations (it is over 500 MB). I've listed the locations on my own web site, http://www.g8wrb.org/useful-stuff/time/HP-5370B/ but in case that is down when someone tries looking for the manual, here they are, along with the locations of the servers. It is clearly worth getting it from a local server, although unfortunately at least 3 of the 4 are in Europe. 1) http://phk.freebsd.dk/HP/5370B.pdf (Danish reserach network) 2) http://nm2.org/files/5370B.pdf (unknown location) 3) http://f1eku.free.fr/From_G8WRB/ (split into 10 sepparte pdf files, hosted in France) 4) http://www.lysator.liu.se/~bg/hp/5370B-600dpi.pdf.gz (hosted in Sweden, compressed with gunzip) A downsampled version at 150 dpi can be found on the Agilent web site. This is much smaller (about 50 MB IIRC). http://www.home.agilent.com/cgi-bin/pub/agilent/Product/cp_Product.jsp?NAV_ID=-536894771.536879850.00LANGUAGE_CODE=engCONTENT_KEY=101408%3aepsg%3aproID=101408%3aepsg%3aproCOUNTRY_CODE=US dave kirkby ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] Power lines and time
At 10:00 AM 8/22/2005, you wrote: Poul-Henning Kamp wrote: In message [EMAIL PROTECTED], Bill Hawkins writes : Power companies bill on time-integrated power - watt-hour meters in the US. Watt-hour meters are still mostly driven by electric clocks, in a way. The frequency does matter. Uhm, sorry, that is just plain wrong. The Ferrantis (sp?) power meter which is the most widely used meter in the world is not frequency sensitive within a band of +/- 10% or more. I have never seen a power meter made by Ferranti in the US. Try Siemens or ABB then, Ferranti has been taken over if I recall. Landis-gyr, definitely, but not Ferranti. To quote Landis-gyr's website: Landis+Gyr Inc. is the world's leading supplier of electricity revenue meters. Our products include solid-state and electromechanical residential meters, a full line of solid-state commercial and industrial meters, high-end precision meters and extensive automated meter reading (AMR) solutions. You cannot make a credible claim of the most widely used meter in the world without including the US. We certainly have as many power meters as all of Europe. You do? Are you sure? Here most of our meters are of the induction type, which work on the principles of a split-phase induction motor. They are very easy to recognize by their horizontal 4 inch corrugated aluminum disk that rotates (hopefully) slowly. That is certainly the case of older meters and in many states. But is most definitely not true of newer meters in many jurisdictions. Many regulators in the US have been very slow on a world basis, to accept newer metering technology, the New York DPS only registering a wide range of fully solid state units in 2003. With the induction type power meter, power line frequency is very important in determining the hours part of kilowatt-hours. Quite true, hence the reason that many electricity sellers are pushing for the introduction of solid-state meters much quicker than many regulators are able to handle. A 10% variation in line frequency would cause a 10% variation in power consumption registered. Induction type power meters will remain accurate with a 10% variation in power line voltage, however. And herein lies a serious problem for electricity suppliers. With the problems of inadequate generating capacity and ever increasing demand, particularly in North America, regulators are directing distributors on occasions to drop nominal voltages to 100V in controlled brown-outs. Induction meters then, apparently, tend to read even lower, thus depriving the distributors of yet more income. Someday, our utilities will convert all of our meters to solidstate units which might not be so frequency sensitive, but that will be a few hundred billion dollars from now. In that case the US will be playing catch up with parts of Canada, Europe, most of Asia and Oceania where solid state meters, often with remote reading are the norm rather than the exception - and synchronised mains frequency has become a fond memory. John Day -Chuck Harris ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
Re: [time-nuts] Low cost synchronization
A couple of points here. Yes, a 10MHz oscillator will severely blast the budget - power wise. But you should remember that 10MHz is also not actually a good frequency for temperature coefficient of crystals - except for SOME SC cut types. Generally speaking the zero tempco rollover frequency for many SC's and most AT's is between 4.5 and 5.5MHz. You can actually get very good tempco's by running two oscillators either 500kHz or 1MHz apart and mixing them. Mounted in a thermal mass but without an oven they will oven give better than TCXO and moderate oven type performance. Real time temperature compensation is actually quite common. In several radio applications I have designed systems using two techniques. 1.. Have the manufacturer supply AT crystals with carefully controlled cut angles - for a given cut angle the tempco will not vary much. Then use a simple compensation table based on angle. 2.. Learn the crystal characteristics. In a couple of chamber runs measure the characteristics of each crystal. You probably only need to do 20 temperatures to cover -10 to +60C. Work out the slope and using some nice interpolation algorithm work out a correction table. Then voltage control the Xtal osc to keep the frequency on target. #2 works well enough that a pretty standard crystal will deliver TCXO or better performance because very few TCXO's use active compensation. But really, can we fit all of this ins key fob? Nope! I suspect in the best research tradition the OP needs to look at WHY his application demands synchronization at this sort of level. In one project where my client initially asked for timing accuracy of this order, we found that we could collect data with timestamps and temperatures, and when we looked at the logger and the data we could measure the offset for a particular logger and then back correct the timestamps on the data. In that case we used a correction system like #1 above, but we had something like 150x50x10mm to work in, not a key fob! John At 02:18 PM 8/18/2005, you wrote: David Andersen wrote: Local stable crystal: Actually, you could make it more than stable enough, but it would exceed your power requirements, because you'd probably fall back to an oven controlled oscillator. There goes your battery. But why did you try your initial experiments with 32.768Khz watch crystals? You're much more likely to find a good, solid 10Mhz reference with an SC cut TCXO. For instance, that maxim IC you mentioned has +- 2ppm, which is really quite awful by instrumentation standards. Compare to this one: http://www.bdelectronic.com/frequency/oscillatorTCXO.html .3ppm tempco, +- 1ppm/year. They don't show their overall allen deviation curves, but you get the idea - it'll be within 1ppm by the end of the year, and since that aging will probably happen over time, I'd guess it would probably get you something like 10 seconds within a year. Or something like: http://www.vectron.com/products/tcxo/tc140.pdf (... which is probably expensive, but which you can get in 0.2 ppm accuracy vs. temperature and 2ppm/10 years). -Dave Dave, The requirement that you seem to have missed is the 18 month battery lifetime. A 10 MHz oscillator is a couple milliapmeres, so it won't do the trick. The watch crystal needs only about 10 microamperes to oscillate. Mike, The 32K crystal may be usable, but you'd have to put some effort into the design to get the temp compensation tuned to the particular crystal, and you'd have to grade the crystals for tempco in the mfg stage. That might be doable in quantity, if you come up with the right sort of computerized test fixture in an oven. I have built a few nixie tube wristwatches using the cheap 32KHz crystals, so I have direct experience in this matter. (Has anyone else on this list built an electronic wristwatch?) Getting the crystal adjusted to 1ppm is not too hard. You'd have to temperature compensate it to get to 0.1 ppm, and that would be limited to perhaps 10C-30C temperature range. It's a lot easier to compensate the crystal if it's worn on the wrist rather than sitting in a car, since a person's wrist is essentially an oven. The real world has ridiculous temperature extremes - don't even think about stabilizing a crystal used outdoors unless it's thermally connected to a human. You should be able to evaluate the feasibility of using a compensated crystal based on the above. ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts ___ time-nuts mailing list time-nuts@febo.com https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
