[time-nuts] Symmetricom 58532A and 58536A group delay figures
Assuming it does not snow again, should finish the cabling to the new rooftop tripod and switch to the new antenna and splitter tomorrow. For the LMR400 main run and jumpers is simple enough, will just measure. That leaves the antenna and splitter, both have and amp and bandpass filter and I am assuming a combined delay that is likely greater than the cable delay given the short runs. Nothing is listed in the datasheets, but they are the semi-marketing sheets (only a couple pages) rather than a proper datasheet. Anyone know what the delay for this amp and splitter is? Or better yet a delay v.s. temp plot? 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.
Re: [time-nuts] E1938A PN measurments
The E1938A uses a crystal that is basically the same as the 10811 crystal except that it is in a reduced height package. However the phase noise is not as good as a 10811 due to broadband noise in the automatic frequency control circuit. By the time I discovered this, it was too late to try to fix it. Rick Karlquist N6RK E1938A designer ___ time-nuts mailing 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] SMT Probing Stuff
This is the one. Sorry for not taking the time to send this in the previous email: http://www.mcmelectronics.com/product/POMONA-5514-/201-075 -Bob On Sat, Sep 29, 2012 at 9:35 PM, Robert Darlington wrote: > On Sat, Sep 29, 2012 at 7:39 PM, gary wrote: >> I've only used 3M clips, so I can't say who makes the best clip. >> >>> http://www.hmcelectronics.com/product/3M/923650-08 >> >> >> There is a gold plated version too. 923655-08 >> >> Pomona might be OK > > I use Pamona "chip clips" (at least that's what *I* call them) and > they work just fine for what I do. They attach to various sized SOIC > chips. > > -Bob ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] SMT Probing Stuff
On Sat, Sep 29, 2012 at 7:39 PM, gary wrote: > I've only used 3M clips, so I can't say who makes the best clip. > >> http://www.hmcelectronics.com/product/3M/923650-08 > > > There is a gold plated version too. 923655-08 > > Pomona might be OK I use Pamona "chip clips" (at least that's what *I* call them) and they work just fine for what I do. They attach to various sized SOIC chips. -Bob ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] SMT Probing Stuff
I bought some 8-pin SMT clips a few years ago, but don't remember where I got them. The only brands I know of are 3M, AP and Pomona. You will find that these things are expensive. Joe Gray W5JG On Sat, Sep 29, 2012 at 7:16 PM, J. Forster wrote: > I recently bought some clean IBM Thinkpads cheap with unknown Boot > PassWords. There is a hack to access the existing PWs and rewrite them, > but it requires connecting to an 8 pin SMT IC. > > I know several vendors make "Dip Clip" type devices for connection to such > chips, but I'd like reccomendations on whose are really any good. > > Also, if anyone has one they'd like to part with, please drop me a note > off line. > > Thanks, > > -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] SMT Probing Stuff
I've only used 3M clips, so I can't say who makes the best clip. http://www.hmcelectronics.com/product/3M/923650-08 There is a gold plated version too. 923655-08 Pomona might be OK. All mine came from failed electronics companies hitting the local surplus shop, but $10 for a clip doesn't sound outrageous. On 9/29/2012 6:16 PM, J. Forster wrote: I recently bought some clean IBM Thinkpads cheap with unknown Boot PassWords. There is a hack to access the existing PWs and rewrite them, but it requires connecting to an 8 pin SMT IC. I know several vendors make "Dip Clip" type devices for connection to such chips, but I'd like reccomendations on whose are really any good. Also, if anyone has one they'd like to part with, please drop me a note off line. Thanks, -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] SMT Probing Stuff
I recently bought some clean IBM Thinkpads cheap with unknown Boot PassWords. There is a hack to access the existing PWs and rewrite them, but it requires connecting to an 8 pin SMT IC. I know several vendors make "Dip Clip" type devices for connection to such chips, but I'd like reccomendations on whose are really any good. Also, if anyone has one they'd like to part with, please drop me a note off line. Thanks, -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] E1938A PN measurments
Bruce Griffiths wrote: Magnus Danielson wrote: On 09/29/2012 02:45 PM, Bruce Griffiths wrote: For those that have Timelab the link to the E1938A PN measurement data is: https://dl.dropbox.com/u/59708595/E1938A.tim Thank you. I will measure mine so that we can compare them. Cross-correlation with a pair of BVAs should do it. Cheers, Magnus I'm still a little suspicious of the result, although measuring a second E1938A removed from a Z3815A produced similar results. I'll measure one of them again with an isolation transformer to eliminate an LF earth loop to see if the earth loop was an issue. Using a single reference (PN floor < -170dBc/Hz) should suffice for this. I didnt have RF isolation transformers available at the time. I have since found that using a single point LF ground (rather than floating the entire interferometer) reduces the interferometer PN floor substantially. Bruce ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. Measuring the E1938A with a single point LF ground produces substantially the same result. A PN measurement using a different technique (classical mixer and low BW PLL) may be useful. Bruce ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] antenna restrictions
:-) Sent from my iPhone On Sep 29, 2012, at 10:01 AM, gandal...@aol.com wrote: > Sounds like we're back to flogging a dead horse:-) > > > In a message dated 29/09/2012 17:32:41 GMT Daylight Time, > scmcgr...@gmail.com writes: > > Just hide the antenna in the whip... Takes care of non magnetic horse > problem > > Sent from my iPhone > > On Sep 28, 2012, at 9:45 PM, "DaveH" wrote: > >> Not gonna work with my Amish neighbors a couple miles up the road. >> >> They have a dead horse up on blocks in their driveway. Non magnetic. >> >> Have a fantastic weekend everyone! >> Dave >> >> >>> -Original Message- >>> From: time-nuts-boun...@febo.com >>> [mailto:time-nuts-boun...@febo.com] On Behalf Of Chris Howard >>> Sent: Friday, September 28, 2012 12:39 >>> To: Discussion of precise time and frequency measurement >>> Subject: [time-nuts] antenna restrictions >>> >>> >>> I don't see what the problem is >>> with HOA's and antenna restrictions. >>> >>> I just put a mag-mount antenna on the car >>> that's up on blocks in the driveway. >>> >>> >>> >>> >>> >>> ( a bit of Mississippi humor for your Friday afternoon :-) ) >>> >>> peace! >>> >>> Chris >>> Columbus, MS >>> >>> ___ >>> time-nuts mailing list -- time-nuts@febo.com >>> To unsubscribe, go to >>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>> and follow the instructions there. >> >> >> ___ >> time-nuts mailing list -- time-nuts@febo.com >> To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> and follow the instructions there. > > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to > https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. > > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] E1938A PN measurments
Magnus Danielson wrote: On 09/29/2012 02:45 PM, Bruce Griffiths wrote: For those that have Timelab the link to the E1938A PN measurement data is: https://dl.dropbox.com/u/59708595/E1938A.tim Thank you. I will measure mine so that we can compare them. Cross-correlation with a pair of BVAs should do it. Cheers, Magnus I'm still a little suspicious of the result, although measuring a second E1938A removed from a Z3815A produced similar results. I'll measure one of them again with an isolation transformer to eliminate an LF earth loop to see if the earth loop was an issue. Using a single reference (PN floor < -170dBc/Hz) should suffice for this. I didnt have RF isolation transformers available at the time. I have since found that using a single point LF ground (rather than floating the entire interferometer) reduces the interferometer PN floor substantially. Bruce ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] "Best" GPSDO
On 09/29/2012 07:52 PM, Bob Camp wrote: Hi The address is pretty easy, the *real* question is when is the swap meet? I just want him to send the stuff to me. ;-) Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] "Best" GPSDO
Hi The address is pretty easy, the *real* question is when is the swap meet? Bob On Sep 29, 2012, at 1:21 PM, Magnus Danielson wrote: > On 09/29/2012 06:19 PM, Tom Knox wrote: >> >> "Best" of course is such a vague question. Best For 5MHz today is a Cesium >> Fountain used periodicly to calibrate 6-12 Symmetricom 5071A option 004 >> disciplining 5-6 Symmetricom Hydrogen Masers disciplining 5-6 Oscilloquartz >> 8607 option 08 BVA's. I am a part owner in just such a system. Notice the >> system ends with quartz and I think therein lies the key. I am a big >> believer that for the best system find the best piece of quartz you budget >> can afford. On eBay I would currently I would argue that the Datum 1000B's >> for around 4-500USD is the way to go. From my experience how you steer it >> and set up your GPS or other timing source is important but only a major >> factor if you do something wrong. > > It's a little out of the hobby budget there. > > If you don't happen to have a caesium fountain, 5071As, masers and loads of > 8607s, there is still a few things to pick up from this setup. > > An atomic clock such as a rubidium can provide holdover and be quieter than > GPS, so you can allow your steering to have long time-constant. Next, you > might not have best wide-band phase-noise, so using a quality oscillator to > achieve that. > > Then again, I can give you an address for those extra 5071As, masers, 8607s > and odd caesium-fountain. :) > > Cheers, > Magnus > > ___ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] messy workbenches
Hi Joe: I've seen her TED Talk: http://www.ted.com/talks/lang/en/temple_grandin_the_world_needs_all_kinds_of_minds.html The movie: Mozart and the Whale is highly recommended. I helps to know what's going on. Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html Joe Leikhim wrote: Brooke; I got a 29. Probably would have been much higher at an earlier age as I have grown out of some things. Not sure how accurate some of the questions relate to AS though. I would have to agree that a lot of engineer and tech types fall into these categories. If not, we would probably not have and GPS satellites, cellphones and supersonic planes.(where is my hoverboard?) Have you seen the Temple Grandin movie? In 1994, I was with my wife and then 9yo son in Estes Park Colorado. We stopped in the public library and this "cow girl" started chatting with us, realizing we were new to town telling us what we might want to see etc.. I could recognize she had some unusual speech traits although AS wasn't well known if at all at the time. Years later I saw Temple Grandin on a TV show and realized she was probably the same "cow girl"! ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] "Best" GPSDO
On 09/29/2012 06:19 PM, Tom Knox wrote: "Best" of course is such a vague question. Best For 5MHz today is a Cesium Fountain used periodicly to calibrate 6-12 Symmetricom 5071A option 004 disciplining 5-6 Symmetricom Hydrogen Masers disciplining 5-6 Oscilloquartz 8607 option 08 BVA's. I am a part owner in just such a system. Notice the system ends with quartz and I think therein lies the key. I am a big believer that for the best system find the best piece of quartz you budget can afford. On eBay I would currently I would argue that the Datum 1000B's for around 4-500USD is the way to go. From my experience how you steer it and set up your GPS or other timing source is important but only a major factor if you do something wrong. It's a little out of the hobby budget there. If you don't happen to have a caesium fountain, 5071As, masers and loads of 8607s, there is still a few things to pick up from this setup. An atomic clock such as a rubidium can provide holdover and be quieter than GPS, so you can allow your steering to have long time-constant. Next, you might not have best wide-band phase-noise, so using a quality oscillator to achieve that. Then again, I can give you an address for those extra 5071As, masers, 8607s and odd caesium-fountain. :) Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] messy workbenches
Brooke; I got a 29. Probably would have been much higher at an earlier age as I have grown out of some things. Not sure how accurate some of the questions relate to AS though. I would have to agree that a lot of engineer and tech types fall into these categories. If not, we would probably not have and GPS satellites, cellphones and supersonic planes.(where is my hoverboard?) Have you seen the Temple Grandin movie? In 1994, I was with my wife and then 9yo son in Estes Park Colorado. We stopped in the public library and this "cow girl" started chatting with us, realizing we were new to town telling us what we might want to see etc.. I could recognize she had some unusual speech traits although AS wasn't well known if at all at the time. Years later I saw Temple Grandin on a TV show and realized she was probably the same "cow girl"! -- Joe Leikhim Leikhim and Associates Communications Consultants Oviedo, Florida jleik...@leikhim.com 407-982-0446 WWW.LEIKHIM.COM ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] antenna restrictions
Sounds like we're back to flogging a dead horse:-) In a message dated 29/09/2012 17:32:41 GMT Daylight Time, scmcgr...@gmail.com writes: Just hide the antenna in the whip... Takes care of non magnetic horse problem Sent from my iPhone On Sep 28, 2012, at 9:45 PM, "DaveH" wrote: > Not gonna work with my Amish neighbors a couple miles up the road. > > They have a dead horse up on blocks in their driveway. Non magnetic. > > Have a fantastic weekend everyone! > Dave > > >> -Original Message- >> From: time-nuts-boun...@febo.com >> [mailto:time-nuts-boun...@febo.com] On Behalf Of Chris Howard >> Sent: Friday, September 28, 2012 12:39 >> To: Discussion of precise time and frequency measurement >> Subject: [time-nuts] antenna restrictions >> >> >> I don't see what the problem is >> with HOA's and antenna restrictions. >> >> I just put a mag-mount antenna on the car >> that's up on blocks in the driveway. >> >> >> >> >> >> ( a bit of Mississippi humor for your Friday afternoon :-) ) >> >> peace! >> >> Chris >> Columbus, MS >> >> ___ >> time-nuts mailing 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] antenna restrictions
Just hide the antenna in the whip... Takes care of non magnetic horse problem Sent from my iPhone On Sep 28, 2012, at 9:45 PM, "DaveH" wrote: > Not gonna work with my Amish neighbors a couple miles up the road. > > They have a dead horse up on blocks in their driveway. Non magnetic. > > Have a fantastic weekend everyone! > Dave > > >> -Original Message- >> From: time-nuts-boun...@febo.com >> [mailto:time-nuts-boun...@febo.com] On Behalf Of Chris Howard >> Sent: Friday, September 28, 2012 12:39 >> To: Discussion of precise time and frequency measurement >> Subject: [time-nuts] antenna restrictions >> >> >> I don't see what the problem is >> with HOA's and antenna restrictions. >> >> I just put a mag-mount antenna on the car >> that's up on blocks in the driveway. >> >> >> >> >> >> ( a bit of Mississippi humor for your Friday afternoon :-) ) >> >> peace! >> >> Chris >> Columbus, MS >> >> ___ >> time-nuts mailing 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] "Best" GPSDO
"Best" of course is such a vague question. Best For 5MHz today is a Cesium Fountain used periodicly to calibrate 6-12 Symmetricom 5071A option 004 disciplining 5-6 Symmetricom Hydrogen Masers disciplining 5-6 Oscilloquartz 8607 option 08 BVA's. I am a part owner in just such a system. Notice the system ends with quartz and I think therein lies the key. I am a big believer that for the best system find the best piece of quartz you budget can afford. On eBay I would currently I would argue that the Datum 1000B's for around 4-500USD is the way to go. From my experience how you steer it and set up your GPS or other timing source is important but only a major factor if you do something wrong. Thomas Knox 1-303-554-0307 > From: li...@rtty.us > Date: Sat, 29 Sep 2012 10:44:07 -0400 > To: time-nuts@febo.com > Subject: Re: [time-nuts] "Best" GPSDO > > Hi > > For close in noise, you can go from 10 to 120 to 14.5 and the net result will > be the same as 10 to 14.5. In the case of 10 to 120, close in might be DC to > 50 Hz or DC to 250 Hz. Past that a reasonable crystal oscillator could beat > the multiplied 10 MHz. In most microwave chains, the low frequency reference > only is responsible for a fairly small range of phase noise offsets. > > For most radio testing, you use wide spaced tones. What you care about is far > removed phase noise rather than close in noise. If you have a tone that's 10 > KHz to 100 KHz away from the passband, phase noise at >10 KHz is what you > would worry about. If you are building a radio with 10 Hz selectivity for 40 > Hz spaced channels, you would worry about close in noise. > > For what ever it's worth, I don't lock up the sources I use for most radio > testing. I just use free running oscillators with good noise characteristics > past 1 KHz. > > Bob > > On Sep 28, 2012, at 11:31 PM, Chris Albertson > wrote: > > > On Fri, Sep 28, 2012 at 5:29 PM, Bob Camp wrote: > >> HI > >> > >> Sort of an open ended question, but there is a fairly simple couple > >> answers: > >> > >> SInce it's close in phase noise and not far removed, things like PLL's are > >> going to transfer it directly from the reference to the output. It will of > >> course scale by 20 log N where N is the amount you multiplied or divided > >> the reference frequency by. Double the frequency and the phase noise goes > >> up by 6 db. > > > > So in my example case of scaling the 10Mhz t-bolt to 14.5Mhz Assuming > > a perfect DDS chip the T-Bolt's phase noise would be scaled up by 20 > > Log(1.45) I'm assuming this works, that I can go from 10MHz to > > 120Mhz and then to 14.5MHZ and the total effect is the same as going > > directly from 10 to 14.5, except for the noise the equipment > > introduces as added. > > > > You can guess the real question here: "how good does the 10MHz > > reference need to be to test real-world receivers? > > > > > > > > > > > > > > -- > > > > Chris Albertson > > Redondo Beach, California > > > > ___ > > time-nuts mailing 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] "Best" GPSDO
Hi For close in noise, you can go from 10 to 120 to 14.5 and the net result will be the same as 10 to 14.5. In the case of 10 to 120, close in might be DC to 50 Hz or DC to 250 Hz. Past that a reasonable crystal oscillator could beat the multiplied 10 MHz. In most microwave chains, the low frequency reference only is responsible for a fairly small range of phase noise offsets. For most radio testing, you use wide spaced tones. What you care about is far removed phase noise rather than close in noise. If you have a tone that's 10 KHz to 100 KHz away from the passband, phase noise at >10 KHz is what you would worry about. If you are building a radio with 10 Hz selectivity for 40 Hz spaced channels, you would worry about close in noise. For what ever it's worth, I don't lock up the sources I use for most radio testing. I just use free running oscillators with good noise characteristics past 1 KHz. Bob On Sep 28, 2012, at 11:31 PM, Chris Albertson wrote: > On Fri, Sep 28, 2012 at 5:29 PM, Bob Camp wrote: >> HI >> >> Sort of an open ended question, but there is a fairly simple couple answers: >> >> SInce it's close in phase noise and not far removed, things like PLL's are >> going to transfer it directly from the reference to the output. It will of >> course scale by 20 log N where N is the amount you multiplied or divided the >> reference frequency by. Double the frequency and the phase noise goes up by >> 6 db. > > So in my example case of scaling the 10Mhz t-bolt to 14.5Mhz Assuming > a perfect DDS chip the T-Bolt's phase noise would be scaled up by 20 > Log(1.45) I'm assuming this works, that I can go from 10MHz to > 120Mhz and then to 14.5MHZ and the total effect is the same as going > directly from 10 to 14.5, except for the noise the equipment > introduces as added. > > You can guess the real question here: "how good does the 10MHz > reference need to be to test real-world receivers? > > > > > > > -- > > Chris Albertson > Redondo Beach, California > > ___ > time-nuts mailing 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] "Best" GPSDO
On 9/28/12 8:31 PM, Chris Albertson wrote: On Fri, Sep 28, 2012 at 5:29 PM, Bob Camp wrote: HI Sort of an open ended question, but there is a fairly simple couple answers: SInce it's close in phase noise and not far removed, things like PLL's are going to transfer it directly from the reference to the output. It will of course scale by 20 log N where N is the amount you multiplied or divided the reference frequency by. Double the frequency and the phase noise goes up by 6 db. So in my example case of scaling the 10Mhz t-bolt to 14.5Mhz Assuming a perfect DDS chip the T-Bolt's phase noise would be scaled up by 20 Log(1.45) I'm assuming this works, that I can go from 10MHz to 120Mhz and then to 14.5MHZ and the total effect is the same as going directly from 10 to 14.5, except for the noise the equipment introduces as added. You can guess the real question here: "how good does the 10MHz reference need to be to test real-world receivers? It has to be quieter than the oscillator in the real world receiver. If your real-wold receiver is a cryogenic ruby maser with a downconveter driven by a hydrogen maser reference, then the answer is "really, really good".. If the real world receiver uses a run of the mill TCXO, then not nearly as good. The 20log10(N) thing does work pretty well. In a PLL synthesizer, you'll pick up a little extra noise from the phase detector and other circuitry, but for back of the envelope to see if your idea is going to work, the 20log10(N) is just fine. This gets into a whole interesting area of microwave source design, because "inside the loop" the phase noise is the reference oscillator multiplied up (20log10(N) noise), and outside the loop, it's the microwave oscillator. So you have an interesting optimization problem, particularly if you want tuning over a wide range. Wide range VCOs implies that the MHz/volt gain is quite high, so noise on the tuning signal shows up on the output. The resonator is often lower Q, so that it can be moved around by the control signal (usually some sort of varactor scheme), and that means the "medium distance away" phase noise suffers. High performance DROs for instance, have a tough time tuning the entire 50 MHz deep space comm bands at 7 or 8 GHz ___ time-nuts mailing 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] messy workbenches
Hi: Recently I've discovered Asperger's Syndrome. Although I don't meet all the criteria, I do have a number of the traits. One is living with clutter (this is different from obsessive hording). A common occupation is engineering. AS people are much more comfortable with things as opposed to people. People who work in technical fields or have strong interests, like extremely precise time, may also have this. To find out you can take an online test at: http://www.aspergerstestsite.com/ or read the Wiki page at: http://en.wikipedia.org/wiki/Asperger_syndrome and a movie: "Mozart and the Whale" that's about this. Have Fun, Brooke Clarke http://www.PRC68.com http://www.end2partygovernment.com/2012Issues.html DaveH wrote: And Bob Pease trumps all: http://eetimes.com/electronics-blogs/other/4217103/How-messy-is-your-desk- There is even a gallery of 24 of Engineering's messiest desks here: http://www.eetimes.com/electronics-blogs/social-mania-blog/4217145/Photo-gal lery--Engineering-s-messiest-desks My primary love is music (analog synthesizers and digital instruments with recording) and the first messy desk pictured is from Christopher Nelson who designs the Sweetwater Sound Creation Station computers -- I own one and love it. It is ironic that: Pease was killed in the crash of his 1969 Volkswagen Beetle, on June 18, 2011. He was leaving a gathering in memory of Jim Williams, who was another well-known analog circuit designer. >From Bob's wikipedia entry: http://en.wikipedia.org/wiki/Bob_Pease Dave (who has a messy workbench but I know where everything is!!!) -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Grant Saviers Sent: Friday, September 28, 2012 18:48 To: time-nuts@febo.com Subject: [time-nuts] messy workbenches George's is a far distant competitor to the bench of the late Jim Williams, see http://www.computerhistory.org/atchm/an-analog-life-rememberin g-jim-williams/ Which was on display at the Computer History Museum and just was returned to Linear Tech. Grant Saviers ___ time-nuts mailing 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] E1938A PN measurments
On 09/29/2012 02:45 PM, Bruce Griffiths wrote: For those that have Timelab the link to the E1938A PN measurement data is: https://dl.dropbox.com/u/59708595/E1938A.tim Thank you. I will measure mine so that we can compare them. Cross-correlation with a pair of BVAs should do it. Cheers, Magnus ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] E1938A PN measurments
For those that have Timelab the link to the E1938A PN measurement data is: https://dl.dropbox.com/u/59708595/E1938A.tim Bruce ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Why the fuss - GPS Interference...
Tom, Nice story. Thanks. Last I heard Rich had moved on from FEI-Zyfer. I don't know where he is now. Nice guy! Rob -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Tom Curlee Sent: 29 September 2012 04:53 To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Why the fuss - GPS Interference... I've also had some odd dealings with Rich Bailey. Some time in the mid 1990's I was a contractor at a USN cal lab. We had sent out a Datum time code generator for repair, and when it came back, one of the functions didn't work. I called Datum and after describing the problem, the tech support guy remembered that there had been a software upgrade, one that, for some unknown reason, had removed the function we needed. He promptly sent me a set of PROMs that had the previous software version and all was well. Skip ahead 6 or 8 years, and I was at a family function and got to talking to my cousins husband. He vaguely mentioned that he worked for a company that 'made very accurate clocks'. For some reason, I blurted out "do you work for Datum?" He was shocked that I knew who, and what, they were. We got to comparing notes, and, yep, same Rich Bailey that sent me the PROMs. I agree, he really is a nice guy. Last I heard, he was the sales manager for FEI-Zyfer. Tom WB6UZZ --- On Fri, 9/28/12, Burt I. Weiner wrote: From: Burt I. Weiner Subject: [time-nuts] Why the fuss - GPS Interference... To: time-nuts@febo.com Date: Friday, September 28, 2012, 9:20 AM Yes, Rob, It was Rich Bailey. A good guy! He worked for DATUM in Anaheim, CA and as I recall, he lived in Riverside. I noticed that he didn't wear a watch and when I jokingly commented about it, considering what he did for a living, he told me that he had been so aware of precise time for so many years that he got tired of knowing precisely what time it was. We had fun together that day. Burt, K6OQK >From: "Rob Kimberley" >To: "'Discussion of precise time and frequency measurement'" > >Subject: Re: [time-nuts] Why the fuss - GPS Interference... > > >Hi Burt, > >This sounds familiar! It wasn't a guy called Rich Bailey was it? That's >what he suggested I do, but I got onto Trimble and got one of their >Bullet antennae with the 3 pole filter (Bullet III?). > >That worked for us. > >Rob Burt I. Weiner Associates Broadcast Technical Services Glendale, California U.S.A. b...@att.net www.biwa.cc K6OQK ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
