[time-nuts] HP 58503A Service Manual with schematics
Does anyone have a service manual for the HP 58503A GPS Time and Frequency Receiver? 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] Low cost GPS module for 100ns timestamping error
I am not advertising for DX but I have bought 4 with good results and their units have a 5 V regulator on it. Some have even a TTL to RS converter on board. Bert Kehren In a message dated 5/2/2014 11:40:47 P.M. Eastern Daylight Time, tn...@toneh.demon.co.uk writes: On 03/05/2014 00:59, ewkeh...@aol.com wrote: Welcome to the nuts Tony Thanks, Bert. You are not specifying exactly how accurate time has to be but in my book and based on tests the most reasonable priced GPS with 1 pps is a Ublox 6M that you can get with antenna for less than $ 22 antenna included from _www.DX.com_ (http://www.DX.com) . They have volume discount. Shipping is very slow but included. They seem to be presently out of the 1 pps version but all ublox units have a 1 pps output and I use with and without and all I do is solder a wire to pin 3. Bert Kehren As I said in my first post I'd like to achieve an accuracy of better than 100ns - or 50ns if possible at reasonable cost. I had come across the Ublox 6M when I was looking earlier, but I misunderstood the data sheet and thought it was only the expensive ($135) LEA/NEO-6T versions which provided timing. Definitely worth a closer look - the NEO-6M is specced at 30ns RMS which is good enough. The power consumption is a little higher than I would have liked at 37mA/3V, but still rather less than others. Thanks, Tony ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Low cost GPS module for 100ns timestamping error
Tony There seem to be many variables. Cost, power, how many, overall stability etc. Most likely you will find that the GPS module is not the most expensive part but the VCXO. It also makes a large difference if it is one off or a larger volume is needed. You can always find a bargain, and maybe a close out sale but if you have to look at a continuous supply the picture changes dramatically and also the design. Bert Kehren In a message dated 5/2/2014 11:40:47 P.M. Eastern Daylight Time, tn...@toneh.demon.co.uk writes: On 03/05/2014 00:59, ewkeh...@aol.com wrote: Welcome to the nuts Tony Thanks, Bert. You are not specifying exactly how accurate time has to be but in my book and based on tests the most reasonable priced GPS with 1 pps is a Ublox 6M that you can get with antenna for less than $ 22 antenna included from _www.DX.com_ (http://www.DX.com) . They have volume discount. Shipping is very slow but included. They seem to be presently out of the 1 pps version but all ublox units have a 1 pps output and I use with and without and all I do is solder a wire to pin 3. Bert Kehren As I said in my first post I'd like to achieve an accuracy of better than 100ns - or 50ns if possible at reasonable cost. I had come across the Ublox 6M when I was looking earlier, but I misunderstood the data sheet and thought it was only the expensive ($135) LEA/NEO-6T versions which provided timing. Definitely worth a closer look - the NEO-6M is specced at 30ns RMS which is good enough. The power consumption is a little higher than I would have liked at 37mA/3V, but still rather less than others. Thanks, Tony ___ 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] SRS FS700 questions
My FS700 arrived yesterday, complete with bonus artistic effects due to the sender believing a thin coat of bubble wrap with an outer layer of cardboard cut from a box and just taped on top, no padding or air gap, would be the obvious way to ship it:-( Physically at least it seems to have survived remarkably well, no damage to the BNCs and the front panel trim, outer covers and transformer cover all looking pretty good again after a couple of hours work. Not having any rack ears attached was probably quite a bonus with it shipped like this! The only obvious internal damage, and it might have been that way before shipping anway, are three vertical inductors held to the circuit board by silicon rubber or hot melt adhesive that are loose but still seem to be electrically connected Anyway, it powered up ok and is indicating it's locked onto Anthorn in the Lessay chain, even if it does believe it's found the never built station at Loop Head in Ireland:-), but I'm not sure if it's functioning properly. It's close enough that I don't want to start pulling it apart for the sake of it without being sure, and it may just be a case of waiting for it to settle, but after showing as locked for several hours the 10MHz output, as indicated both by the internal display and an external counter, is swinging back and forth quite rapidly anywhere within approx +/- 3 parts in 10^9. There was an obvious change in the crystal oscillator frequency as the oven warmed, and another when the conditioning seemed to take over, but it's been hunting like this ever since it first indicated lock and with no obvious change, just when I do think it might be converging it opens up again. So first question is, can anyone tell me please if this is normal or close enough that I should expect it to settle eventually, or do I need to start investigating further? Second question, could somebody confirm please whether or not the LCD display is supposed to be backlit? This one isn't, but it's not immediately obvious from photos I've found online whether or not it should be, and although the contrast range on this seems to be fine it's certainly not easy to see. Last question, for now at least:-), this unit has the FS800 PCB rev C, with revision 2.0 firmware, does anyone know if any later firmware is available that includes Anthorn, or at least Rugby, as part of the Lessay chain? Regards Nigel GM8PZR ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Low cost GPS module for 100ns timestamping error
Tony, Chris, Bert, Since all you want is a 10 ns time stamp / data logger you do not need a GPSDO, or OCXO, or VCXO. The solution is cheap and very simple. Your GPS receiver provides a 1PPS to the microprocessor. Use a plain XO or TCXO; the frequency does not need to be accurate, just stable to about 1e-9 (many $1 xtals do this). Each second your code [re]computes the drift between the clock and GPS. You may average over 10 to 100 seconds if you wish. Even though your clock is off-time and off-frequency your software knows what the offset is. Therefore, you can simply adjust the time stamp reading by the current clock error. This software GPSDO gives equal or actually slightly better performance than a real GPDSO but it is much simpler: no DAC, no EFC, no OCXO, no VCXO, no PLL. /tvb (i5s) ___ 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] SRS FS700 questions
Hello Nigel, I would consider doing the maintenance/calibration/performance verification procedure in the manual. A procedure will show if you have equal swing on the VCXO about the center freq needed. The VCXO can be mechanically adjusted for center of the VCXO electronic control range. I recall no backlight on the LCD on mine. It has been awhile since I last turned mine on. Stan, W1LE On 03-May-14 12:57 PM, gandal...@aol.com wrote: My FS700 arrived yesterday, complete with bonus artistic effects due to the sender believing a thin coat of bubble wrap with an outer layer of cardboard cut from a box and just taped on top, no padding or air gap, would be the obvious way to ship it:-( Physically at least it seems to have survived remarkably well, no damage to the BNCs and the front panel trim, outer covers and transformer cover all looking pretty good again after a couple of hours work. Not having any rack ears attached was probably quite a bonus with it shipped like this! The only obvious internal damage, and it might have been that way before shipping anway, are three vertical inductors held to the circuit board by silicon rubber or hot melt adhesive that are loose but still seem to be electrically connected Anyway, it powered up ok and is indicating it's locked onto Anthorn in the Lessay chain, even if it does believe it's found the never built station at Loop Head in Ireland:-), but I'm not sure if it's functioning properly. It's close enough that I don't want to start pulling it apart for the sake of it without being sure, and it may just be a case of waiting for it to settle, but after showing as locked for several hours the 10MHz output, as indicated both by the internal display and an external counter, is swinging back and forth quite rapidly anywhere within approx +/- 3 parts in 10^9. There was an obvious change in the crystal oscillator frequency as the oven warmed, and another when the conditioning seemed to take over, but it's been hunting like this ever since it first indicated lock and with no obvious change, just when I do think it might be converging it opens up again. So first question is, can anyone tell me please if this is normal or close enough that I should expect it to settle eventually, or do I need to start investigating further? Second question, could somebody confirm please whether or not the LCD display is supposed to be backlit? This one isn't, but it's not immediately obvious from photos I've found online whether or not it should be, and although the contrast range on this seems to be fine it's certainly not easy to see. Last question, for now at least:-), this unit has the FS800 PCB rev C, with revision 2.0 firmware, does anyone know if any later firmware is available that includes Anthorn, or at least Rugby, as part of the Lessay chain? Regards Nigel GM8PZR ___ 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] SRS FS700 questions
Hi Stan Many thanks for the advice, I was a bit concerned about making any adjustments until I'd confirmed it at least appeared to be working correctly but I've just taken another look at the manual and can't see any reason why I shouldn't. One of my reasons for concern was that although this isn't an option 01 unit SRS seems to have upgraded the OCXOs to beyond the original basic spec, it's currently fitted with an SRS low noise SC10, and as it stands I'm getting the impression I'd be better off just killing the Loran input and letting it free run:-) BTW, the SC10 OCXO manual seems to be one of the few SRS manuals available online that does contain the schematic. Thanks too for the feedback on the LCD backlight, I've found nothing so far to suggest it should be backlit but it could certainly do with it. Regards Nigel GM8PZR In a message dated 03/05/2014 20:19:14 GMT Daylight Time, stanw...@verizon.net writes: Hello Nigel, I would consider doing the maintenance/calibration/performance verification procedure in the manual. A procedure will show if you have equal swing on the VCXO about the center freq needed. The VCXO can be mechanically adjusted for center of the VCXO electronic control range. I recall no backlight on the LCD on mine. It has been awhile since I last turned mine on. Stan, W1LE On 03-May-14 12:57 PM, gandal...@aol.com wrote: My FS700 arrived yesterday, complete with bonus artistic effects due to the sender believing a thin coat of bubble wrap with an outer layer of cardboard cut from a box and just taped on top, no padding or air gap, would be the obvious way to ship it:-( Physically at least it seems to have survived remarkably well, no damage to the BNCs and the front panel trim, outer covers and transformer cover all looking pretty good again after a couple of hours work. Not having any rack ears attached was probably quite a bonus with it shipped like this! The only obvious internal damage, and it might have been that way before shipping anway, are three vertical inductors held to the circuit board by silicon rubber or hot melt adhesive that are loose but still seem to be electrically connected Anyway, it powered up ok and is indicating it's locked onto Anthorn in the Lessay chain, even if it does believe it's found the never built station at Loop Head in Ireland:-), but I'm not sure if it's functioning properly. It's close enough that I don't want to start pulling it apart for the sake of it without being sure, and it may just be a case of waiting for it to settle, but after showing as locked for several hours the 10MHz output, as indicated both by the internal display and an external counter, is swinging back and forth quite rapidly anywhere within approx +/- 3 parts in 10^9. There was an obvious change in the crystal oscillator frequency as the oven warmed, and another when the conditioning seemed to take over, but it's been hunting like this ever since it first indicated lock and with no obvious change, just when I do think it might be converging it opens up again. So first question is, can anyone tell me please if this is normal or close enough that I should expect it to settle eventually, or do I need to start investigating further? Second question, could somebody confirm please whether or not the LCD display is supposed to be backlit? This one isn't, but it's not immediately obvious from photos I've found online whether or not it should be, and although the contrast range on this seems to be fine it's certainly not easy to see. Last question, for now at least:-), this unit has the FS800 PCB rev C, with revision 2.0 firmware, does anyone know if any later firmware is available that includes Anthorn, or at least Rugby, as part of the Lessay chain? Regards Nigel GM8PZR ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
Re: [time-nuts] Low cost GPS module for 100ns timestamping error
On Sat, 03 May 2014 02:38:07 +0100 Tony tn...@toneh.demon.co.uk wrote: On 03/05/2014 00:59, ewkeh...@aol.com wrote: Welcome to the nuts Tony Thanks, Bert. You are not specifying exactly how accurate time has to be but in my book and based on tests the most reasonable priced GPS with 1 pps is a Ublox 6M that you can get with antenna for less than $ 22 antenna included from _www.DX.com_ (http://www.DX.com) . They have volume discount. Shipping is very slow but included. They seem to be presently out of the 1 pps version but all ublox units have a 1 pps output and I use with and without and all I do is solder a wire to pin 3. Bert Kehren As I said in my first post I'd like to achieve an accuracy of better than 100ns - or 50ns if possible at reasonable cost. I had come across the Ublox 6M when I was looking earlier, but I misunderstood the data sheet and thought it was only the expensive ($135) LEA/NEO-6T versions which provided timing. Definitely worth a closer look - the NEO-6M is specced at 30ns RMS which is good enough. The power consumption is a little higher than I would have liked at 37mA/3V, but still rather less than others. Thanks, Tony ___ I hope I'm not getting to philosophical here, but isn't the time stamp accuracy measured between receivers? That is, if I have two GPSDO, they are guarenteed to be within X amount of time from each other. Or do you consider a time stamp to be absolute? ___ 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.
