[time-nuts] f.s. SULZER 5A
For sale a working Sulzer frequency standard 5A 5 MHz oscillator complete with power supply, rack mount. I ask 180 Euro. Location Italy. Example shipping cost: to Germany 40 Euro (via ground 10-15 Kg)no tracking nr. Other options available. Email me directly to: tim...@timeok.it Luciano ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] 57600 baud rate with Basic etc
Corby, Power Basic certainly does the job. However, there's a fairly big learning curve. I use Just Basic, which is a FREE cut-down version of Liberty Basic. While there are a few limitations, and some things you need to do aren't entirely intuitive, it works very well and the serial comms support is excellent. Not only will it do the higher speeds, it will also talk to any COM port you like, including those USB serial adaptors which typically live up at COM6 or higher. What's more Just Basic works great with Win7. I've attached a screen-shot of one of my programs which drives a serial DDS synthesizer (the FEI FE-56xx Rb synth). Looks good and works great. Regards, Murray ZL1BPU attachment: Rb MEPT.png___ time-nuts mailing 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] To use or not to use transmission line splitters for GPS receivers
On 10/10/2012 06:30 AM, Hal Murray wrote: albertson.ch...@gmail.com said: The satellites are in 12 hour orbits. Everything repeats every 12 hours. But the sun is on a 24 hr. period and if you did two 12 hour tests you don't want to do one at night and one in day. So start each test at the same time of day let it run for 12+ hours. Thanks. After poking around a bit... That's 12 Sidereal hours rather than 12 UTC hours. Rarther, it's 11 hours and 58 minutes UTC. It revolves about 2x366.35 times the globe over a year. I don't remember why they choose such an orbit, but it has its uses. 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] To use or not to use transmission line splitters for GPS receivers
Hi! I forgot to mention, but the peak group delay of a pole pair is d_peak = 2*Q/w0 = Q / (pi * f0) Hence, the group delay increases linearly with increasing Q values. Shift the Q, and your delay vary, shift the center-frequency, and you dip off the peak. Cheers, Magnus On 10/09/2012 10:55 PM, Magnus Danielson wrote: On 10/09/2012 09:27 PM, John Ackermann N8UR wrote: Here's a link to a USNO paper that measured the tempco of three GPS amplifiers: http://www.dtic.mil/cgi-bin/GetTRDoc?AD=ADA490830 They found that amplifier filtering was the prime cause of tempco, and the narrowest bandpass amplifier they looked at had a group delay range of 4 nanoseconds over the range of -15 to +45 degrees C. This is a good paper. I've read it before. It presents three strategies for GPS amplifiers: 1) Wide-band amplifier, represented by the AOA Wideband amplifier 2) Narrow-band amplifier with peaks, represented by the AOA narrow band amplifier 3) Narrow-band amplifier with no peaks, represented by the KW microwave phase-stable narrow band amplifier. The wide-band amplifier has around 4 ns group delay, and it is fairly flat and stable. Since there isn't much delay to start with, it doesn't change a whole lot either. Since the amplifier isn't very flat, it also has some variations in group delay. It's fairly natural. The downside is that it has no suppression of interference, so we should do some damping. The second case tries to achieve just that, but in order to create steep slopes around the pass-band, they have used two resonances, one on each side of the pass-band. You see the peaking effect on the gain curve of figure 1, but oh... they show up clearly in the group delay measurement of figure 2 too. This is expected from the theory, as these two pole-pairs has fairly high Q, their group delay will show this property in the direct vicinity of their respective resonances, just as their contribution to gain will do. So, nice steep slopes and good suppression, but lots of group delay, and by that higher sensitivity to environmental effects, i.e. temperature. The third example shows wider but much flatter amplitude response, and essentially flat group delay. This is what you expect from maximum flat group delay filters such as Bessel/Thompson. No wonders those are specified as measuring filters for digital transmission. Lesser delay, and lesser sensitivity. The downside is that the cost of steep slopes comes from a higher number of needed poles/zeros. Just as I expect from traditional signal theory. Again, you get what you pay for. Now you know why I want a network analyzer reaching this area at home. 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] To use or not to use transmission line splitters for GPS receivers
Hi …. and if we have to go to something more exotic than simple two pole filters the group delay (and it's variation) has got to go up. At least some of the HP splitters have RF filters in them. The same is true of GPS receivers. A receiver or splitter in the attic will have many of the same group delay issues as an antenna. I know, who would put one in the attic. Just how warm does that rack get as the air-conditioning cycles and the vents clog up? Bob On Oct 10, 2012, at 4:11 AM, Magnus Danielson mag...@rubidium.dyndns.org wrote: Hi! I forgot to mention, but the peak group delay of a pole pair is d_peak = 2*Q/w0 = Q / (pi * f0) Hence, the group delay increases linearly with increasing Q values. Shift the Q, and your delay vary, shift the center-frequency, and you dip off the peak. Cheers, Magnus On 10/09/2012 10:55 PM, Magnus Danielson wrote: On 10/09/2012 09:27 PM, John Ackermann N8UR wrote: Here's a link to a USNO paper that measured the tempco of three GPS amplifiers: http://www.dtic.mil/cgi-bin/GetTRDoc?AD=ADA490830 They found that amplifier filtering was the prime cause of tempco, and the narrowest bandpass amplifier they looked at had a group delay range of 4 nanoseconds over the range of -15 to +45 degrees C. This is a good paper. I've read it before. It presents three strategies for GPS amplifiers: 1) Wide-band amplifier, represented by the AOA Wideband amplifier 2) Narrow-band amplifier with peaks, represented by the AOA narrow band amplifier 3) Narrow-band amplifier with no peaks, represented by the KW microwave phase-stable narrow band amplifier. The wide-band amplifier has around 4 ns group delay, and it is fairly flat and stable. Since there isn't much delay to start with, it doesn't change a whole lot either. Since the amplifier isn't very flat, it also has some variations in group delay. It's fairly natural. The downside is that it has no suppression of interference, so we should do some damping. The second case tries to achieve just that, but in order to create steep slopes around the pass-band, they have used two resonances, one on each side of the pass-band. You see the peaking effect on the gain curve of figure 1, but oh... they show up clearly in the group delay measurement of figure 2 too. This is expected from the theory, as these two pole-pairs has fairly high Q, their group delay will show this property in the direct vicinity of their respective resonances, just as their contribution to gain will do. So, nice steep slopes and good suppression, but lots of group delay, and by that higher sensitivity to environmental effects, i.e. temperature. The third example shows wider but much flatter amplitude response, and essentially flat group delay. This is what you expect from maximum flat group delay filters such as Bessel/Thompson. No wonders those are specified as measuring filters for digital transmission. Lesser delay, and lesser sensitivity. The downside is that the cost of steep slopes comes from a higher number of needed poles/zeros. Just as I expect from traditional signal theory. Again, you get what you pay for. Now you know why I want a network analyzer reaching this area at home. 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. ___ time-nuts mailing 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] 57600 baud rate with Basic etc
Murray we offered up the same thing for pretty much the same reasons. Good to know I am in fine company. Hmmm Ham + free??? Any link? Regards Paul WB8TSL On Wed, Oct 10, 2012 at 4:05 AM, Murray Greenman denw...@orcon.net.nzwrote: Corby, Power Basic certainly does the job. However, there's a fairly big learning curve. I use Just Basic, which is a FREE cut-down version of Liberty Basic. While there are a few limitations, and some things you need to do aren't entirely intuitive, it works very well and the serial comms support is excellent. Not only will it do the higher speeds, it will also talk to any COM port you like, including those USB serial adaptors which typically live up at COM6 or higher. What's more Just Basic works great with Win7. I've attached a screen-shot of one of my programs which drives a serial DDS synthesizer (the FEI FE-56xx Rb synth). Looks good and works great. Regards, Murray ZL1BPU ___ time-nuts mailing 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] 57600 baud rate with Basic etc
You know there is one other aspect of this question from Corby. How do I say this. Age. If you are using the old basics then things like the latest basic by different names are quite convoluted and distracting. They are designed for mobile phone apps. You know those crazy modern apps that sell. We time nuts need direct control of older equipment. So things like liberty basic or powerbasic will get us what we want quicker. I have never figured out why HP did not develop USB in 1969? Not very far sighted. ;-) Regards Paul WB8TSL On Wed, Oct 10, 2012 at 9:36 AM, paul swed paulsw...@gmail.com wrote: Murray we offered up the same thing for pretty much the same reasons. Good to know I am in fine company. Hmmm Ham + free??? Any link? Regards Paul WB8TSL On Wed, Oct 10, 2012 at 4:05 AM, Murray Greenman denw...@orcon.net.nzwrote: Corby, Power Basic certainly does the job. However, there's a fairly big learning curve. I use Just Basic, which is a FREE cut-down version of Liberty Basic. While there are a few limitations, and some things you need to do aren't entirely intuitive, it works very well and the serial comms support is excellent. Not only will it do the higher speeds, it will also talk to any COM port you like, including those USB serial adaptors which typically live up at COM6 or higher. What's more Just Basic works great with Win7. I've attached a screen-shot of one of my programs which drives a serial DDS synthesizer (the FEI FE-56xx Rb synth). Looks good and works great. Regards, Murray ZL1BPU ___ time-nuts mailing 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] 57600 baud rate with Basic etc
What aspects of USB would HP have used? Just the complexity of a USB OHCI/UHCI would have been economically prohibitive compared to an asynchronous serial UART. An OHCI/UHCI is more like an ethernet controller and those took up the space of entire expansion boards initially. What they did come up with was HP-IB although I would have preferred it to be serial and galvanically isolated. On Wed, 10 Oct 2012 10:28:46 -0400, paul swed paulsw...@gmail.com wrote: I have never figured out why HP did not develop USB in 1969? Not very far sighted. ;-) Regards Paul WB8TSL ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] To use or not to use transmission line, splitters for GPS receivers
On 10/10/2012 8:00 AM, time-nuts-requ...@febo.com wrote: albertson.ch...@gmail.com said: The satellites are in 12 hour orbits. Everything repeats every 12 hours. But the sun is on a 24 hr. period and if you did two 12 hour tests you don't want to do one at night and one in day. So start each test at the same time of day let it run for 12+ hours. Thanks. After poking around a bit... That's 12 Sidereal hours rather than 12 UTC hours. Rarther, it's 11 hours and 58 minutes UTC. It revolves about 2x366.35 times the globe over a year. I don't remember why they choose such an orbit, but it has its uses. Cheers, Magnus Isn't that half of a sidereal day? A sidereal day being ~4 minutes shorter than UTC day... ___ time-nuts mailing 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] To use or not to use transmission line, splitters for GPS receivers
Hi: The reason for the GPS orbits is so that the ground track repeats. Have Fun, Brooke On 10/10/2012 8:00 AM, time-nuts-requ...@febo.com wrote: albertson.ch...@gmail.com said: The satellites are in 12 hour orbits. Everything repeats every 12 hours. But the sun is on a 24 hr. period and if you did two 12 hour tests you don't want to do one at night and one in day. So start each test at the same time of day let it run for 12+ hours. Thanks. After poking around a bit... That's 12 Sidereal hours rather than 12 UTC hours. Rarther, it's 11 hours and 58 minutes UTC. It revolves about 2x366.35 times the globe over a year. I don't remember why they choose such an orbit, but it has its uses. Cheers, Magnus Isn't that half of a sidereal day? A sidereal day being ~4 minutes shorter than UTC day... ___ time-nuts mailing 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] 57600 baud rate with Basic etc
David it was humor Regards On Wed, Oct 10, 2012 at 10:53 AM, David davidwh...@gmail.com wrote: What aspects of USB would HP have used? Just the complexity of a USB OHCI/UHCI would have been economically prohibitive compared to an asynchronous serial UART. An OHCI/UHCI is more like an ethernet controller and those took up the space of entire expansion boards initially. What they did come up with was HP-IB although I would have preferred it to be serial and galvanically isolated. On Wed, 10 Oct 2012 10:28:46 -0400, paul swed paulsw...@gmail.com wrote: I have never figured out why HP did not develop USB in 1969? Not very far sighted. ;-) Regards Paul WB8TSL ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] 57600 baud rate with Basic etc
Ah well, I missed it but only because I have seen other people make the same suggestion seriously in the recent past. Where is my box of 2102 DRAMs? I left it around here somewhere. On Wed, 10 Oct 2012 11:15:32 -0400, paul swed paulsw...@gmail.com wrote: David it was humor Regards On Wed, Oct 10, 2012 at 10:53 AM, David davidwh...@gmail.com wrote: What aspects of USB would HP have used? Just the complexity of a USB OHCI/UHCI would have been economically prohibitive compared to an asynchronous serial UART. An OHCI/UHCI is more like an ethernet controller and those took up the space of entire expansion boards initially. What they did come up with was HP-IB although I would have preferred it to be serial and galvanically isolated. On Wed, 10 Oct 2012 10:28:46 -0400, paul swed paulsw...@gmail.com wrote: I have never figured out why HP did not develop USB in 1969? Not very far sighted. ;-) Regards Paul WB8TSL ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] 57600 baud rate with Basic???
Hi Corby, Do consider John's TimeLab program: Windows, free, easy to use, wonderful live plots, phase, frequency, ADEV, etc. You will be amazed. Download from http://www.ke5fx.com/timelab/readme.htm It supports the SR620 directly as well as a number of other popular counters. For unusual instruments, there's a tab called acquire from counter in talk-only mode which can be used to capture serial phase or frequency data (at any baud rate). I use this feature myself; I suspect it would work for you as well. Not only would it solve your BASIC baud rate problem but it would also give you real-time logging and plotting capability. /tvb - Original Message - From: cdel...@juno.com To: time-nuts@febo.com Sent: Tuesday, October 09, 2012 10:44 AM Subject: [time-nuts] 57600 baud rate with Basic??? Hi, I'm currently using a GWBasic program at 9600 Baud to get 1 second T.I. data (12 digits) from an SR620 counter, display the reading , put the reading into a file, name the file sequentialy, and either save or delete the file via a function key. I'm switching to a new counter that outputs at 57600 Baud (9 digits). Is there a version of Basic I can use that would support that 57600 Baud rate? Thanks, Corby ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] 57600 baud rate with Basic etc
Hi If they had done USB instead of HPIB / GPIB, a lot of the drivers would have been out of service by the time Windows 95 came along. No chance at all of them working under Windows 7. For the complexity, it'd have been better if they used something more like Ethernet. Except in 1968, you would have set up for something other than TCP-IP. Anybody running a Token Ring network in the basement? No easy solution. Serial com is still with us because it's a lowest common denominator. I'm sitting here coding it into a new product right now (once the uber super compiler finishes a build). It's supported on just about every chip set in the universe. I suspect it will outlive the cockroaches. Bob -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of David Sent: Wednesday, October 10, 2012 10:54 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] 57600 baud rate with Basic etc What aspects of USB would HP have used? Just the complexity of a USB OHCI/UHCI would have been economically prohibitive compared to an asynchronous serial UART. An OHCI/UHCI is more like an ethernet controller and those took up the space of entire expansion boards initially. What they did come up with was HP-IB although I would have preferred it to be serial and galvanically isolated. On Wed, 10 Oct 2012 10:28:46 -0400, paul swed paulsw...@gmail.com wrote: I have never figured out why HP did not develop USB in 1969? Not very far sighted. ;-) Regards Paul WB8TSL ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] 57600 baud rate with Basic etc
On 10/10/2012 11:49 AM, Bob Camp wrote: No easy solution. Serial com is still with us because it's a lowest common denominator. I'm sitting here coding it into a new product right now (once the uber super compiler finishes a build). It's supported on just about every chip set in the universe. I suspect it will outlive the cockroaches. Basic serial has its merits, but it's regrettable that RS-232 came out on top. RS-422 (or full-duplex RS-485, not much difference) would have been a much better choice. Differential so it has good noise resistance, and it doesn't use weird voltages (-12V? come on...) It all looks the same from the software side though. Bytes in, bytes out. -- m. tharp ___ time-nuts mailing 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] 57600 baud rate with Basic etc
Hi Again, I'd say it's the lowest common denominator. Synchronous comm using RS-232 levels on a DB-25 came before asynchronous comm. It's long dead. Being first isn't *always* best. Same could be said of 125V / 60 ma current loops. I suspect serial will easily outlive RS-232 levels though. Bob -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Michael Tharp Sent: Wednesday, October 10, 2012 11:55 AM To: time-nuts@febo.com Subject: Re: [time-nuts] 57600 baud rate with Basic etc On 10/10/2012 11:49 AM, Bob Camp wrote: No easy solution. Serial com is still with us because it's a lowest common denominator. I'm sitting here coding it into a new product right now (once the uber super compiler finishes a build). It's supported on just about every chip set in the universe. I suspect it will outlive the cockroaches. Basic serial has its merits, but it's regrettable that RS-232 came out on top. RS-422 (or full-duplex RS-485, not much difference) would have been a much better choice. Differential so it has good noise resistance, and it doesn't use weird voltages (-12V? come on...) It all looks the same from the software side though. Bytes in, bytes out. -- m. tharp ___ time-nuts mailing 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] 57600 baud rate with Basic etc
Commodore computers in the longago dimdark past serialized the GPIB. They started out with the GPIB as the disk drive and printer interface from the get-go. I used a Commodore as a cheap controller when Hp GPIB controllers cost a small fortune. Don David What aspects of USB would HP have used? Just the complexity of a USB OHCI/UHCI would have been economically prohibitive compared to an asynchronous serial UART. An OHCI/UHCI is more like an ethernet controller and those took up the space of entire expansion boards initially. What they did come up with was HP-IB although I would have preferred it to be serial and galvanically isolated. On Wed, 10 Oct 2012 10:28:46 -0400, paul swed paulsw...@gmail.com wrote: I have never figured out why HP did not develop USB in 1969? Not very far sighted. ;-) Regards Paul WB8TSL ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. -- Neither the voice of authority nor the weight of reason and argument are as significant as experiment, for thence comes quiet to the mind. De Erroribus Medicorum, R. Bacon, 13th century. If you don't know what it is, don't poke it. Ghost in the Shell Dr. Don Latham AJ7LL Six Mile Systems LLP 17850 Six Mile Road POB 134 Huson, MT, 59846 VOX 406-626-4304 www.lightningforensics.com www.sixmilesystems.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] To use or not to use transmission line, splitters for GPS receivers
On 10/10/12 8:10 AM, bro...@pacific.net wrote: Hi: The reason for the GPS orbits is so that the ground track repeats. Have Fun, Brooke and that makes it easy to predict visibility. Tomorrow will be the same as today, shifted by 4 minutes. ___ time-nuts mailing 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] To use or not to use transmission line, splitters for GPS receivers
. Tomorrow will be the same as today, shifted by 4 minutes. Seems to work as a predictor for a lot of things :)... Bob ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
[time-nuts] Stanford RS620 Acting up
My RS620 became difficult to start some time back with me having to press the power button several times. Now it has been off a few months and will not turn on at all. The fan starts but no indicators. If I press on and off several time I saw the numeric LEDs flash briefly a few time but the unit does not come up. I suspect that there is a bad electrolytic cap in the power supply somewhere. Before I get into it I wanted to ask if this is a common failure mode with a common fix? Regards, Eric Haskell ___ time-nuts mailing 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] To use or not to use transmission line splitters for GPS receivers
On 10/10/2012 01:09 PM, Bob Camp wrote: Hi …. and if we have to go to something more exotic than simple two pole filters the group delay (and it's variation) has got to go up. Yes and no. As you add pole-pairs, their group delay contributions adds up. However, as you add pole-pairs you also get a pair of zeros for the slopes (typically located in 0 and infinity for band-pass response) and you can back off considerably in Q values, and aim for maximum flat group delay in the pass-band. See the difference between the amplifiers in the article. At least some of the HP splitters have RF filters in them. The same is true of GPS receivers. A receiver or splitter in the attic will have many of the same group delay issues as an antenna. I know, who would put one in the attic. Just how warm does that rack get as the air-conditioning cycles and the vents clog up? The filters do add up, true. But then one should also recall the cable in the total, as covered by others. 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] Stanford RS620 Acting up
The SR620 I worked on was unused for a long time, and would not turn on. Seems the power switch was oxidized and would not self-clean. Had to unmount it so I could use chemical cleaners without getting any residue on the case or PCB. IIRC the whole front panel needed to be pulled to do that (not too difficult). Beware the SR620 is slightly unusual in that the transformer is not switched, but rather the DC supplies are. Bob L. From: Eric Haskell eric_hask...@hotmail.com To: Time Nuts time-nuts@febo.com Sent: Wed, October 10, 2012 4:59:51 PM Subject: [time-nuts] Stanford RS620 Acting up My RS620 became difficult to start ... ___ time-nuts mailing 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] To use or not to use transmission line splitters for GPS receivers
On Oct 10, 2012, at 5:05 PM, Magnus Danielson mag...@rubidium.dyndns.org wrote: On 10/10/2012 01:09 PM, Bob Camp wrote: Hi …. and if we have to go to something more exotic than simple two pole filters the group delay (and it's variation) has got to go up. Yes and no. As you add pole-pairs, their group delay contributions adds up. However, as you add pole-pairs you also get a pair of zeros for the slopes (typically located in 0 and infinity for band-pass response) and you can back off considerably in Q values, and aim for maximum flat group delay in the pass-band. See the difference between the amplifiers in the article. Unless you need to go to something with sharp skirts. Then you are likely to start from a fairly high Q lowpass prototype and add a delay equalizer. Starts to add up pretty fast... At least some of the HP splitters have RF filters in them. The same is true of GPS receivers. A receiver or splitter in the attic will have many of the same group delay issues as an antenna. I know, who would put one in the attic. Just how warm does that rack get as the air-conditioning cycles and the vents clog up? The filters do add up, true. But then one should also recall the cable in the total, as covered by others. indeed, but it's a bit tough to keep the cable all indoors. 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] To use or not to use transmission line splitters for GPS receivers
On 10/11/2012 12:03 AM, Bob Camp wrote: On Oct 10, 2012, at 5:05 PM, Magnus Danielsonmag...@rubidium.dyndns.org wrote: On 10/10/2012 01:09 PM, Bob Camp wrote: Hi …. and if we have to go to something more exotic than simple two pole filters the group delay (and it's variation) has got to go up. Yes and no. As you add pole-pairs, their group delay contributions adds up. However, as you add pole-pairs you also get a pair of zeros for the slopes (typically located in 0 and infinity for band-pass response) and you can back off considerably in Q values, and aim for maximum flat group delay in the pass-band. See the difference between the amplifiers in the article. Unless you need to go to something with sharp skirts. Then you are likely to start from a fairly high Q lowpass prototype and add a delay equalizer. Starts to add up pretty fast... True. But we are talking about wise design for GPS antenna use. At least some of the HP splitters have RF filters in them. The same is true of GPS receivers. A receiver or splitter in the attic will have many of the same group delay issues as an antenna. I know, who would put one in the attic. Just how warm does that rack get as the air-conditioning cycles and the vents clog up? The filters do add up, true. But then one should also recall the cable in the total, as covered by others. indeed, but it's a bit tough to keep the cable all indoors. Indeed it is, which is why it may contribute significantly unless done with care. I do know those that temperature stabilizes both the concrete pillar and cable conduct. 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] To use or not to use transmission line splitters for GPS receivers
On Oct 10, 2012, at 7:03 PM, Magnus Danielson mag...@rubidium.dyndns.org wrote: On 10/11/2012 12:03 AM, Bob Camp wrote: On Oct 10, 2012, at 5:05 PM, Magnus Danielsonmag...@rubidium.dyndns.org wrote: On 10/10/2012 01:09 PM, Bob Camp wrote: Hi …. and if we have to go to something more exotic than simple two pole filters the group delay (and it's variation) has got to go up. Yes and no. As you add pole-pairs, their group delay contributions adds up. However, as you add pole-pairs you also get a pair of zeros for the slopes (typically located in 0 and infinity for band-pass response) and you can back off considerably in Q values, and aim for maximum flat group delay in the pass-band. See the difference between the amplifiers in the article. Unless you need to go to something with sharp skirts. Then you are likely to start from a fairly high Q lowpass prototype and add a delay equalizer. Starts to add up pretty fast... True. But we are talking about wise design for GPS antenna use. …. unless we suddenly need much steeper skirts due to a change in band allocations. At least some of the HP splitters have RF filters in them. The same is true of GPS receivers. A receiver or splitter in the attic will have many of the same group delay issues as an antenna. I know, who would put one in the attic. Just how warm does that rack get as the air-conditioning cycles and the vents clog up? The filters do add up, true. But then one should also recall the cable in the total, as covered by others. indeed, but it's a bit tough to keep the cable all indoors. Indeed it is, which is why it may contribute significantly unless done with care. I do know those that temperature stabilizes both the concrete pillar and cable conduct. 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] 57600 baud rate with Basic etc
I design in asynchronous serial for diagnostics all of the time. It is easy to galvanically isolate if necessary, is easy to debug, uses the fewest pins, and is well supported on both ends although if needed, USB to serial translation always seems to cause more problems than it solves. I do not remember now where I saw it but many years ago, I ran across an RS-232 type of interface where the first edge of the start bit was used as the high precision timing reference for the following message. I am not sure of the exact details but as I recall, the UART had some external glue logic and maybe a synchronous clock so the start bit edge was aligned to the timing reference to within the inherent jitter of the glue logic without any clock uncertainty. The receiver had a standard UART with a parallel low jitter logic path to watch for the start bit. On Wed, 10 Oct 2012 11:49:13 -0400, Bob Camp li...@rtty.us wrote: Hi If they had done USB instead of HPIB / GPIB, a lot of the drivers would have been out of service by the time Windows 95 came along. No chance at all of them working under Windows 7. For the complexity, it'd have been better if they used something more like Ethernet. Except in 1968, you would have set up for something other than TCP-IP. Anybody running a Token Ring network in the basement? No easy solution. Serial com is still with us because it's a lowest common denominator. I'm sitting here coding it into a new product right now (once the uber super compiler finishes a build). It's supported on just about every chip set in the universe. I suspect it will outlive the cockroaches. Bob -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of David Sent: Wednesday, October 10, 2012 10:54 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] 57600 baud rate with Basic etc What aspects of USB would HP have used? Just the complexity of a USB OHCI/UHCI would have been economically prohibitive compared to an asynchronous serial UART. An OHCI/UHCI is more like an ethernet controller and those took up the space of entire expansion boards initially. What they did come up with was HP-IB although I would have preferred it to be serial and galvanically isolated. On Wed, 10 Oct 2012 10:28:46 -0400, paul swed paulsw...@gmail.com wrote: I have never figured out why HP did not develop USB in 1969? Not very far sighted. ;-) Regards Paul WB8TSL ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] To use or not to use transmission line splitters for GPS receivers
mag...@rubidium.dyndns.org said: I do know those that temperature stabilizes both the concrete pillar and cable conduct. I hadn't thought about the support pillar. CTE of concrete is 8-12 PPM/C, so a 10 C change would be 100 PPM. 10 meters would be 1000 micrometers or 1 mm. I think that's 3 picoseconds. I couldn't measure that, but I expect it's important for the big boys. I was thinking of 10 meters as being the height of a building. A stand alone pillar in the middle of a field wouldn't need to be that tall. The cable to the lab would be longer, but you could run two cables and measure the length of the other one with TDR. I was thinking of a pillar as primarily in the vertical direction so maybe it doesn't matter as much. But if it's on the corner of a building, maybe the whole building shrinks/grows in the horizontal dimensions too. Most buildings are more than 10 meters long, but the temperature on the inside is usually constant so maybe the building doesn't change size much in any dimension. What's the temperature time constant of a building or (unheated) antenna pillar? What's the skin depth at 24 hours or 1 year? (Steel is the same ballpark: 14 PPM/C) -- These are my opinions. I hate spam. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
