Re: [time-nuts] ! PPS Source
e...@telight.com said: > I'm also aware that some people have come up with external sawtooth > correction, using programmable digital delay lines and special control > circuits. But, why do all that if you can just fix the clock instead? Have you ever worked on a large software project? The API to the GPS module lets you split the software into two parts -- and the GPS part will be written and maintained by somebody else. You don't necessarily need the digital delay line. You can measure the offset between the PPS from the GPS and the PPS from the GPS and do the sawtooth correction in software. -- These are my opinions. I hate spam. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] ! PPS Source
Hi > On Aug 13, 2020, at 6:35 PM, ed breya wrote: > > I have often wondered about all this sawtooth correction stuff, and I think > I've asked here too, but never got a definitive answer. Every time this comes > up, there are all sorts of explanations of the characteristic, and inevitably > someone mentions the T-bolt having its internal GPS clock synchronized with > the desired ideal 10 MHz output, either eliminating or greatly reducing the > sawtooth effect. But, to my knowledge, nobody has said for sure if this is > indeed the case, or whether that's all it takes to achieve perfection, or if > more magic is needed besides synchronizing. Properly steering the clock that supplies the pps divider is what is needed. There is no *direct* need to use that clock for the GPS. A GPSDO *is* a device that steers the clock that supplies the pps divider. (Yes, there are other ways to get it done) > I'm also aware that some people have come up with external sawtooth > correction, using programmable digital delay lines and special control > circuits. But, why do all that if you can just fix the clock instead? Because you can’t “fix the clock” on a GPS module. That’s what’ this is all about. The GPS *modules* ( = little PCB GPS receivers ) don’t steer their clock. > > Many years ago I looked at my Motorola Oncore VP (or whatever model is used > in the HPZ3801A), to see what its clock was, and if it was reasonably > possible to synthesize it from the 10 MHz. I think the clock is a Motorola > brand odd looking TCXO, labeled "19096" or something like that, probably > 19.096 MHz, as I recall. That's about as far as I got. Since then I've just > wondered what would happen if it was synthesized from the 10 MHz, or if it > was even worth trying, or if it would result in other problems. If you multiply 10 MHz directly to GPS band you may have issues …. > Maybe a certain amount of dither is necessary for proper operation. It’s more an issue of spurs. > > So, here are some questions, that if answered, may go a long way toward > possible improvements in our GPS stuff. > > 1. If the GPS RX module's internal clock is synthesized (to the same nominal > frequency) from the 10 MHz output of the GPSDO, can that alone eliminate or > substantially reduce the sawtooth effect? How are you doing the “synthesized”? Indeed pulse dropping *is* a version of synthesis. If you phase lock the local clock to the GPS code clock, that will duplicate what the TBolt does. > > 2. Does the T-bolt actually do this, and if so, is that all it takes? They phase lock the local 10 MHz OCXO to the GPS code clock. > > If either answer is yes, then I would think the GPS RX makers would have > provisions for external clock reference, at least for certain high-grade > timing type models.m That sounds wonderful. It turns out to cost money. Since you can get the job done just fine with the software correction, why double (or whatever) the price of the module? If I was designing a device (like a GPSDO) the lowest cost device with the best accuracy will be the winner Needless to say, anything that pumps up the price is a major downer. (at least that’s how it worked for the decades I did do this for a living ….). > > 3. Do any GPS RX modules have such provision? No not on the low cost parts. That’s for the simple reason that OEM users of these modules are quite happy doing it with the sawtooth message. It’s dirt cheap to implement and has very few downside issues. Bob > > That's all I can think of for now. > > Ed > > > > ___ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] eLORAN will be on the air GRI 99600
Its been stable for several hours. So who knows. Regards Paul. On Thu, Aug 13, 2020 at 8:17 PM Dana Whitlow wrote: > Sudden changes in amplitude or phase can also be a local phenomenon, > like a loose joint in a rain gutter system for example. One would think > that > such a problem in a high power transmitter installation would be setting > off alarms all over the place and probably automatically tripping the > transmitter off. > > Dana > > > On Thu, Aug 13, 2020 at 4:59 PM paul swed wrote: > > > Actually its stranger than that they were down 10db and now are back up > to > > -71 thats typical here. Its kind of cutting in and out like a bad antenna > > connection at 75,000 watts. Yikes. > > > > On Thu, Aug 13, 2020 at 5:06 PM paul swed wrote: > > > > > Yes they are on the air. A bit down today at -80db normally -70. > > > > > > On Thu, Aug 13, 2020 at 4:48 PM David G. McGaw < > > > david.g.mc...@dartmouth.edu> wrote: > > > > > >> Hi Paul, > > >> > > >> Is Wildwood transmitting now or will they be? I am not seeing > anything > > >> in NH. > > >> > > >> Thanks, > > >> > > >> David N1HAC > > >> > > >> On 8/5/20 10:00 AM, paul swed wrote: > > >> > Hello to fellow time nuts. > > >> > Warm up those old Austrons. eLORAN out of New Jersey has been on the > > air > > >> > intermittently prior to a test run next week. Due to the storm they > > have > > >> > lost power and should have it back today or tomorrow. > > >> > The intention will be on the air operation till the 20th. That's a > > long > > >> > run. Nice. > > >> > Seems the Austron 2100s can be had for reasonable money these days > > also. > > >> > Enjoy. > > >> > Paul > > >> > WB8TSL > > >> > ___ > > >> > time-nuts mailing list -- time-nuts@lists.febo.com > > >> > To unsubscribe, go to > > >> > > > https://nam12.safelinks.protection.outlook.com/?url=http%3A%2F%2Flists.febo.com%2Fmailman%2Flistinfo%2Ftime-nuts_lists.febo.com&data=02%7C01%7Cdavid.g.mcgaw%40dartmouth.edu%7Cac55ba07ba7e44c56e0408d83949707e%7C995b093648d640e5a31ebf689ec9446f%7C0%7C0%7C637322334868061249&sdata=ITxnnUFmF7%2F9U2dn25pwR8upRiBuSg6Uzw49CxxZBMQ%3D&reserved=0 > > >> > and follow the instructions there. > > >> > > >> > > >> ___ > > >> time-nuts mailing list -- time-nuts@lists.febo.com > > >> To unsubscribe, go to > > >> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > > >> and follow the instructions there. > > >> > > > > > ___ > > time-nuts mailing list -- time-nuts@lists.febo.com > > To unsubscribe, go to > > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > > and follow the instructions there. > > > ___ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. > ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] HP 58503A GPS receiver not locking to GPS
Have you manually set the date/time yet? Last time I powered mine up. I had to update the current time and date and it locked right up. -Eric On Thu, Aug 13, 2020, 1:55 PM Dr. David Kirkby < drkir...@kirkbymicrowave.co.uk> wrote: > Some time ago my GPS receiver would not lock to GPS. I put this down to the > fact the antenna had got tilted over quite a bit, and since I was not > needing the receiver, it got switched off, and I forgot about it for some > time. > > I've since straightened the antenna up, and push it a little higher - it is > now about 3 m above ground > > However, the unit will not lock, despite being on for a couple of days. The > status shows "attempting to lock", but does not actually lock one > satellite. I set the and time manually, as well as latitude, longitude, and > antenna height. I've also set the elevation mask to 10 degrees. > > The data below shows some results of :system:status? over a period of a > little over two hours. I've run self-tests, and they all pass okay. The > occasional error below, such as E-113, it just where I have mis-typed > something. If I type *CLS, the display shows scpi> > > I'm a bit concerned if the mode of "hold" is correct, but I'm unsure. > > Has anyone got any suggestions as to what I can do to get it to lock? > > scpi > :system:sy > E-113> :system:status? > --- Receiver Status > --- > > SYNCHRONIZATION ... [ Outputs > Invalid ] > SmartClock Mode ___ Reference Outputs > ___ >Locked TFOM 9 > FFOM 3 >Recovery 1PPS TI -- >Holdover HOLD THR 1.000 us > >> Power-up: GPS acquisition Holdover Uncertainty > > Predict -- > > ACQUISITION .. [ GPS 1PPS > Invalid ] > Tracking: 0 Not Tracking: 12 ___ Time > >PRN El Az PRN El Az UTC 17:53:34 [?] 13 Aug > 2020 >* 1 -- ---7 39 159 GPS 1PPS Invalid: not > tracking > 2 46 286 * 8 -- --- ANT DLY 0 ns >* 3 -- ---9 77 72 Position > > 4 37 64 *10 -- --- MODE Hold > 5 17 292 *11 -- --- > 6 54 214 *30 15 182 LAT N 51:39:04.128 > LON E 0:46:36.375 > ELEV MASK 10 deg *attempting to track HGT +46.29 m > (MSL) > HEALTH MONITOR . [ > OK ] > Self Test: OKInt Pwr: OK Oven Pwr: OK OCXO: OK EFC: OK GPS Rcv: > OK > E-113> *CLS > scpi > :system:status? > --- Receiver Status > --- > > SYNCHRONIZATION ... [ Outputs > Invalid ] > SmartClock Mode ___ Reference Outputs > ___ >Locked TFOM 9 > FFOM 3 >Recovery 1PPS TI -- >Holdover HOLD THR 1.000 us > >> Power-up: GPS acquisition Holdover Uncertainty > > Predict -- > > ACQUISITION .. [ GPS 1PPS > Invalid ] > Tracking: 0 Not Tracking: 12 ___ Time > >PRN El Az PRN El Az UTC 17:54:01 [?] 13 Aug > 2020 >* 1 -- ---7 39 159 GPS 1PPS Invalid: not > tracking > 2 46 286 * 8 -- --- ANT DLY 0 ns >* 3 -- ---9 76 72 Position > > 4 37 64 *10 -- --- MODE Hold > 5 18 292 *11 -- --- > 6 54 214 *30 15 182 LAT N 51:39:04.128 > LON E 0:46:36.375 > ELEV MASK 10 deg *attempting to track HGT +46.29 m > (MSL) > HEALTH MONITOR . [ > OK ] > Self Test: OKInt Pwr: OK Oven Pwr: OK OCXO: OK EFC: OK GPS Rcv: > OK > scpi > :system:status? > --- Receiver Status > --- > > SYNCHRONIZATION ... [ Outputs > Invalid ] > SmartClock Mode ___ Reference Outputs > ___ >Locked TFOM 9 > FFOM 3 >Recovery 1PPS TI -- >Holdover
Re: [time-nuts] Oscillatek 2352
ed wrote:
I'd recommend against offsetting the device ground * * *
In actual application, you should go ahead and provide the +/-
tune voltage range. It's a little more complicated since you'll need a
negative supply or offset * * *
It's fairly easy to make quiet, low current negative supplies from the
+12 V, if no other ready source is available from the system.
The dawning of the low voltage, rail-to-rail opamp age has created a new
class of low-power, inverting switching ICs with integrated, low-voltage
negative regulators. These are designed to offset the opamp's negative
supply rail below ground so that RRO opamps can truly pull their outputs
all the way to ground, not just within millivolts. Two good examples
are the LM7705 ("low noise negative bias generator") and the LTC1550,
but the list is expanding every quarter.
Note that these inverters use internal oscillators at frequencies much
lower than 10MHz, so there is a possibility of mixing and beating as Ed
noted. Also, anyone going this way should make sure the regulator
output is sufficient to handle the oscillator's needs under all conditions.
Best regards,
Charles
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Re: [time-nuts] eLORAN will be on the air GRI 99600
Sudden changes in amplitude or phase can also be a local phenomenon, like a loose joint in a rain gutter system for example. One would think that such a problem in a high power transmitter installation would be setting off alarms all over the place and probably automatically tripping the transmitter off. Dana On Thu, Aug 13, 2020 at 4:59 PM paul swed wrote: > Actually its stranger than that they were down 10db and now are back up to > -71 thats typical here. Its kind of cutting in and out like a bad antenna > connection at 75,000 watts. Yikes. > > On Thu, Aug 13, 2020 at 5:06 PM paul swed wrote: > > > Yes they are on the air. A bit down today at -80db normally -70. > > > > On Thu, Aug 13, 2020 at 4:48 PM David G. McGaw < > > david.g.mc...@dartmouth.edu> wrote: > > > >> Hi Paul, > >> > >> Is Wildwood transmitting now or will they be? I am not seeing anything > >> in NH. > >> > >> Thanks, > >> > >> David N1HAC > >> > >> On 8/5/20 10:00 AM, paul swed wrote: > >> > Hello to fellow time nuts. > >> > Warm up those old Austrons. eLORAN out of New Jersey has been on the > air > >> > intermittently prior to a test run next week. Due to the storm they > have > >> > lost power and should have it back today or tomorrow. > >> > The intention will be on the air operation till the 20th. That's a > long > >> > run. Nice. > >> > Seems the Austron 2100s can be had for reasonable money these days > also. > >> > Enjoy. > >> > Paul > >> > WB8TSL > >> > ___ > >> > time-nuts mailing list -- time-nuts@lists.febo.com > >> > To unsubscribe, go to > >> > https://nam12.safelinks.protection.outlook.com/?url=http%3A%2F%2Flists.febo.com%2Fmailman%2Flistinfo%2Ftime-nuts_lists.febo.com&data=02%7C01%7Cdavid.g.mcgaw%40dartmouth.edu%7Cac55ba07ba7e44c56e0408d83949707e%7C995b093648d640e5a31ebf689ec9446f%7C0%7C0%7C637322334868061249&sdata=ITxnnUFmF7%2F9U2dn25pwR8upRiBuSg6Uzw49CxxZBMQ%3D&reserved=0 > >> > and follow the instructions there. > >> > >> > >> ___ > >> time-nuts mailing list -- time-nuts@lists.febo.com > >> To unsubscribe, go to > >> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > >> and follow the instructions there. > >> > > > ___ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. > ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] eLORAN will be on the air GRI 99600
it seemed to act up for a bit this afternoon and has been solid for 2 hours at least. Regards On Thu, Aug 13, 2020 at 5:28 PM paul swed wrote: > Actually its stranger than that they were down 10db and now are back up to > -71 thats typical here. Its kind of cutting in and out like a bad antenna > connection at 75,000 watts. Yikes. > > On Thu, Aug 13, 2020 at 5:06 PM paul swed wrote: > >> Yes they are on the air. A bit down today at -80db normally -70. >> >> On Thu, Aug 13, 2020 at 4:48 PM David G. McGaw < >> david.g.mc...@dartmouth.edu> wrote: >> >>> Hi Paul, >>> >>> Is Wildwood transmitting now or will they be? I am not seeing anything >>> in NH. >>> >>> Thanks, >>> >>> David N1HAC >>> >>> On 8/5/20 10:00 AM, paul swed wrote: >>> > Hello to fellow time nuts. >>> > Warm up those old Austrons. eLORAN out of New Jersey has been on the >>> air >>> > intermittently prior to a test run next week. Due to the storm they >>> have >>> > lost power and should have it back today or tomorrow. >>> > The intention will be on the air operation till the 20th. That's a long >>> > run. Nice. >>> > Seems the Austron 2100s can be had for reasonable money these days >>> also. >>> > Enjoy. >>> > Paul >>> > WB8TSL >>> > ___ >>> > time-nuts mailing list -- time-nuts@lists.febo.com >>> > To unsubscribe, go to >>> https://nam12.safelinks.protection.outlook.com/?url=http%3A%2F%2Flists.febo.com%2Fmailman%2Flistinfo%2Ftime-nuts_lists.febo.com&data=02%7C01%7Cdavid.g.mcgaw%40dartmouth.edu%7Cac55ba07ba7e44c56e0408d83949707e%7C995b093648d640e5a31ebf689ec9446f%7C0%7C0%7C637322334868061249&sdata=ITxnnUFmF7%2F9U2dn25pwR8upRiBuSg6Uzw49CxxZBMQ%3D&reserved=0 >>> > and follow the instructions there. >>> >>> >>> ___ >>> time-nuts mailing list -- time-nuts@lists.febo.com >>> To unsubscribe, go to >>> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com >>> and follow the instructions there. >>> >> ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] ! PPS Source
I have often wondered about all this sawtooth correction stuff, and I think I've asked here too, but never got a definitive answer. Every time this comes up, there are all sorts of explanations of the characteristic, and inevitably someone mentions the T-bolt having its internal GPS clock synchronized with the desired ideal 10 MHz output, either eliminating or greatly reducing the sawtooth effect. But, to my knowledge, nobody has said for sure if this is indeed the case, or whether that's all it takes to achieve perfection, or if more magic is needed besides synchronizing. I'm also aware that some people have come up with external sawtooth correction, using programmable digital delay lines and special control circuits. But, why do all that if you can just fix the clock instead? Many years ago I looked at my Motorola Oncore VP (or whatever model is used in the HPZ3801A), to see what its clock was, and if it was reasonably possible to synthesize it from the 10 MHz. I think the clock is a Motorola brand odd looking TCXO, labeled "19096" or something like that, probably 19.096 MHz, as I recall. That's about as far as I got. Since then I've just wondered what would happen if it was synthesized from the 10 MHz, or if it was even worth trying, or if it would result in other problems. Maybe a certain amount of dither is necessary for proper operation. So, here are some questions, that if answered, may go a long way toward possible improvements in our GPS stuff. 1. If the GPS RX module's internal clock is synthesized (to the same nominal frequency) from the 10 MHz output of the GPSDO, can that alone eliminate or substantially reduce the sawtooth effect? 2. Does the T-bolt actually do this, and if so, is that all it takes? If either answer is yes, then I would think the GPS RX makers would have provisions for external clock reference, at least for certain high-grade timing type models. 3. Do any GPS RX modules have such provision? That's all I can think of for now. Ed ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] eLORAN will be on the air GRI 99600
Actually its stranger than that they were down 10db and now are back up to -71 thats typical here. Its kind of cutting in and out like a bad antenna connection at 75,000 watts. Yikes. On Thu, Aug 13, 2020 at 5:06 PM paul swed wrote: > Yes they are on the air. A bit down today at -80db normally -70. > > On Thu, Aug 13, 2020 at 4:48 PM David G. McGaw < > david.g.mc...@dartmouth.edu> wrote: > >> Hi Paul, >> >> Is Wildwood transmitting now or will they be? I am not seeing anything >> in NH. >> >> Thanks, >> >> David N1HAC >> >> On 8/5/20 10:00 AM, paul swed wrote: >> > Hello to fellow time nuts. >> > Warm up those old Austrons. eLORAN out of New Jersey has been on the air >> > intermittently prior to a test run next week. Due to the storm they have >> > lost power and should have it back today or tomorrow. >> > The intention will be on the air operation till the 20th. That's a long >> > run. Nice. >> > Seems the Austron 2100s can be had for reasonable money these days also. >> > Enjoy. >> > Paul >> > WB8TSL >> > ___ >> > time-nuts mailing list -- time-nuts@lists.febo.com >> > To unsubscribe, go to >> https://nam12.safelinks.protection.outlook.com/?url=http%3A%2F%2Flists.febo.com%2Fmailman%2Flistinfo%2Ftime-nuts_lists.febo.com&data=02%7C01%7Cdavid.g.mcgaw%40dartmouth.edu%7Cac55ba07ba7e44c56e0408d83949707e%7C995b093648d640e5a31ebf689ec9446f%7C0%7C0%7C637322334868061249&sdata=ITxnnUFmF7%2F9U2dn25pwR8upRiBuSg6Uzw49CxxZBMQ%3D&reserved=0 >> > and follow the instructions there. >> >> >> ___ >> time-nuts mailing list -- time-nuts@lists.febo.com >> To unsubscribe, go to >> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com >> and follow the instructions there. >> > ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] ! PPS Source
kb...@n1k.org said: > The TBolt is a GPSDO rather than a GPS module. Itâs a very different beast > than a ZED-F9P. ZED-F9T, or the M-12 the OP is using. At least some GPSDOs contain a GPS module. The Z3801A and friends are an example. Are their any significant advantages to one way or the other? I assume the TBolt approach is harder to do if you don't already have a software team writing GPS code. How many major brands of GPSDO are there? Does anybody have a list? What fraction use a GPS module? -- These are my opinions. I hate spam. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] eLORAN will be on the air GRI 99600
Yes they are on the air. A bit down today at -80db normally -70. On Thu, Aug 13, 2020 at 4:48 PM David G. McGaw wrote: > Hi Paul, > > Is Wildwood transmitting now or will they be? I am not seeing anything > in NH. > > Thanks, > > David N1HAC > > On 8/5/20 10:00 AM, paul swed wrote: > > Hello to fellow time nuts. > > Warm up those old Austrons. eLORAN out of New Jersey has been on the air > > intermittently prior to a test run next week. Due to the storm they have > > lost power and should have it back today or tomorrow. > > The intention will be on the air operation till the 20th. That's a long > > run. Nice. > > Seems the Austron 2100s can be had for reasonable money these days also. > > Enjoy. > > Paul > > WB8TSL > > ___ > > time-nuts mailing list -- time-nuts@lists.febo.com > > To unsubscribe, go to > https://nam12.safelinks.protection.outlook.com/?url=http%3A%2F%2Flists.febo.com%2Fmailman%2Flistinfo%2Ftime-nuts_lists.febo.com&data=02%7C01%7Cdavid.g.mcgaw%40dartmouth.edu%7Cac55ba07ba7e44c56e0408d83949707e%7C995b093648d640e5a31ebf689ec9446f%7C0%7C0%7C637322334868061249&sdata=ITxnnUFmF7%2F9U2dn25pwR8upRiBuSg6Uzw49CxxZBMQ%3D&reserved=0 > > and follow the instructions there. > > > ___ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. > ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] HP 58503A GPS receiver not locking to GPS
Some time ago my GPS receiver would not lock to GPS. I put this down to the fact the antenna had got tilted over quite a bit, and since I was not needing the receiver, it got switched off, and I forgot about it for some time. I've since straightened the antenna up, and push it a little higher - it is now about 3 m above ground However, the unit will not lock, despite being on for a couple of days. The status shows "attempting to lock", but does not actually lock one satellite. I set the and time manually, as well as latitude, longitude, and antenna height. I've also set the elevation mask to 10 degrees. The data below shows some results of :system:status? over a period of a little over two hours. I've run self-tests, and they all pass okay. The occasional error below, such as E-113, it just where I have mis-typed something. If I type *CLS, the display shows scpi> I'm a bit concerned if the mode of "hold" is correct, but I'm unsure. Has anyone got any suggestions as to what I can do to get it to lock? scpi > :system:sy E-113> :system:status? --- Receiver Status --- SYNCHRONIZATION ... [ Outputs Invalid ] SmartClock Mode ___ Reference Outputs ___ Locked TFOM 9 FFOM 3 Recovery 1PPS TI -- Holdover HOLD THR 1.000 us >> Power-up: GPS acquisition Holdover Uncertainty Predict -- ACQUISITION .. [ GPS 1PPS Invalid ] Tracking: 0 Not Tracking: 12 ___ Time PRN El Az PRN El Az UTC 17:53:34 [?] 13 Aug 2020 * 1 -- ---7 39 159 GPS 1PPS Invalid: not tracking 2 46 286 * 8 -- --- ANT DLY 0 ns * 3 -- ---9 77 72 Position 4 37 64 *10 -- --- MODE Hold 5 17 292 *11 -- --- 6 54 214 *30 15 182 LAT N 51:39:04.128 LON E 0:46:36.375 ELEV MASK 10 deg *attempting to track HGT +46.29 m (MSL) HEALTH MONITOR . [ OK ] Self Test: OKInt Pwr: OK Oven Pwr: OK OCXO: OK EFC: OK GPS Rcv: OK E-113> *CLS scpi > :system:status? --- Receiver Status --- SYNCHRONIZATION ... [ Outputs Invalid ] SmartClock Mode ___ Reference Outputs ___ Locked TFOM 9 FFOM 3 Recovery 1PPS TI -- Holdover HOLD THR 1.000 us >> Power-up: GPS acquisition Holdover Uncertainty Predict -- ACQUISITION .. [ GPS 1PPS Invalid ] Tracking: 0 Not Tracking: 12 ___ Time PRN El Az PRN El Az UTC 17:54:01 [?] 13 Aug 2020 * 1 -- ---7 39 159 GPS 1PPS Invalid: not tracking 2 46 286 * 8 -- --- ANT DLY 0 ns * 3 -- ---9 76 72 Position 4 37 64 *10 -- --- MODE Hold 5 18 292 *11 -- --- 6 54 214 *30 15 182 LAT N 51:39:04.128 LON E 0:46:36.375 ELEV MASK 10 deg *attempting to track HGT +46.29 m (MSL) HEALTH MONITOR . [ OK ] Self Test: OKInt Pwr: OK Oven Pwr: OK OCXO: OK EFC: OK GPS Rcv: OK scpi > :system:status? --- Receiver Status --- SYNCHRONIZATION ... [ Outputs Invalid ] SmartClock Mode ___ Reference Outputs ___ Locked TFOM 9 FFOM 3 Recovery 1PPS TI -- Holdover HOLD THR 1.000 us >> Power-up: GPS acquisition Holdover Uncertainty Predict -- ACQUISITION .. [ GPS 1PPS Invalid ] Tracking: 0 Not Tracking: 12 ___ Time PRN El Az PRN El Az UTC 18:00:50 [?] 13 Aug 2020 2 47 282 *11 -- ---
Re: [time-nuts] ! PPS Source
(At least older) Novatel receivers can be set to lock the internal oscillator. /Björn Sent from my iPhone > On 13 Aug 2020, at 18:26, David C. Partridge > wrote: > > IIRC the Thunderbolt DOES lock its internal clock to the GPS > > David > - ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Oscillatek 2352
Pete wrote: "I'm planning to hook it up as an external reference for an HP59309A clock. Now my thought is to put a Schottky diode in the ground leg of the oscillator (to raise the ground reference slightly), then use a trim-pot on the CV input to fine-tune it." I'd recommend against offsetting the device ground - it's OK for experimenting, but may cause all sorts of troubles in actual application. Does this part have mechanical access to the coarse tuning inside? I'm assuming probably not, so you're kind of stuck with the existing tune range, but at least it passes through the 10 MHz ideal value. In actual application, you should go ahead and provide the +/- tune voltage range. It's a little more complicated since you'll need a negative supply or offset, but will be much cleaner than moving the ground. If it's for a dedicated, non-critical application, and you do the ground offset, it would be much more stable with a shunt regulator IC rather than a rectifier junction. The lowest commercial types are around 1.22 V. I can't recall all the ones available, but I always remember the classic ICL8069, as a starting point to think about. There are newer ones that can take lots more current. Also of course, if you move the case/DC ground, you need make sure it's solidly bypassed to earth/system ground, and the 10 MHz output and its ground (if necessary) are AC coupled to the outside world. It's fairly easy to make quiet, low current negative supplies from the +12 V, if no other ready source is available from the system. The simplest is to use the 10 MHz output signal to drive a small amplifier or 74HC04 (or HC24X/54X for more power), which can supply a charge pump circuit to make other voltages. Running it at the 10 MHz avoids making other frequencies that could interfere (but there will be harmonics). At this speed, use small signal Schottky diodes as rectifiers. The associated capacitors will be small, around the nF range, so it can be quite compact overall. There are also tricks you can do with opto-couplers to make DC offset voltages at small current. Ed ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] eLORAN will be on the air GRI 99600
Hi Paul, Is Wildwood transmitting now or will they be? I am not seeing anything in NH. Thanks, David N1HAC On 8/5/20 10:00 AM, paul swed wrote: Hello to fellow time nuts. Warm up those old Austrons. eLORAN out of New Jersey has been on the air intermittently prior to a test run next week. Due to the storm they have lost power and should have it back today or tomorrow. The intention will be on the air operation till the 20th. That's a long run. Nice. Seems the Austron 2100s can be had for reasonable money these days also. Enjoy. Paul WB8TSL ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to https://nam12.safelinks.protection.outlook.com/?url=http%3A%2F%2Flists.febo.com%2Fmailman%2Flistinfo%2Ftime-nuts_lists.febo.com&data=02%7C01%7Cdavid.g.mcgaw%40dartmouth.edu%7Cac55ba07ba7e44c56e0408d83949707e%7C995b093648d640e5a31ebf689ec9446f%7C0%7C0%7C637322334868061249&sdata=ITxnnUFmF7%2F9U2dn25pwR8upRiBuSg6Uzw49CxxZBMQ%3D&reserved=0 and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] ! PPS Source
Hi The TBolt is a GPSDO rather than a GPS module. It’s a very different beast than a ZED-F9P. ZED-F9T, or the M-12 the OP is using. Bob > On Aug 13, 2020, at 12:09 PM, David C. Partridge > wrote: > > IIRC the Thunderbolt DOES lock its internal clock to the GPS > > David > -Original Message- > From: time-nuts [mailto:time-nuts-boun...@lists.febo.com] On Behalf Of Bob > kb8tq > Sent: 13 August 2020 14:39 > To: Discussion of precise time and frequency measurement > Subject: Re: [time-nuts] ! PPS Source > > Hi > > Here’s the “whole story”, sorry if it repeats things you already know … > > All GPS modules that I have ever seen use a free running clock. The internal > oscillator is *not* locked to GPS. When they want to generate a 1 pps output > they drop / add cycles from the the internal oscillator to get it “as close > as > possible”. That means that you will always have an error in the PPS. > > Since they *know* this is going on, many devices report this error on a > second by second basis. Since the error looks like a sawtooth if you graph > it, this is often called “sawtooth correction”. This correction also takes > care > of “hanging bridges” where the sawtooth stays to one side or the other of > “correct” for a long time. > > Normally when feeding a PRS-10, the sawtooth correction is not used. That > results in a degraded pps accuracy. The best GPS module to use in this > case is one with a very small sawtooth “window” ( = a fast internal clock). > Right now, the Furuno parts are winning this particular race. > > If you *do* use the sawtooth correction (possibly by feeding a variable > delay line chip), then indeed the F9P and F9T will do a much better job. > > Some numbers: > > Sawtooth on some older modules can be out around +/- 20 ns On newer > parts it might be down around +/-10 ns. On the F9 parts it is +/-4 ns. The > Furuno parts run half that. > > Corrected, on a modern part, and looking at second to second variation, > you can get below 1 ns with various modules. On the F9’s you can get well > below 1 ns. > > = > > All of that is looking at short term variation. Your Rb does not move much > short term (unless the temperature changes …). Its stability and aging likely > are quite good. > > GPS (as received / uncorrected ) swings around a bit during a normal day. > Swings of 10 to 20 ns are pretty normal. > 50 ns is possible under odd > conditions. That’s more than your Rb is likely to move around over a 4 to 12 > hour period. > > If you “follow” GPS with your Rb through a conventional loop, you likely > degrade the stability of the Rb. It takes a fairly fancy loop to do a good job > on an Rb. > > Bob > >> On Aug 12, 2020, at 11:44 PM, Joe Hobart wrote: >> >> I have been using 1 PPS from a Motorola M-12 timing module to steer a SRS >> PRS-10. I recently heard that a U-Blox ZED F9P module receives both L1 and >> L2 >> and can provide much improved positional accuracy. >> >> Would better positions translate into a smoother 1 PPS? Does anyone have >> experience with this U-Blox module? Can this be set up with a fixed >> position as >> a timing module? >> >> Is there a better source of 1 PPS at a reasonable cost? The U-Blox is about >> $200. >> >> Thanks, >> Joe, W7LUX >> >> --- >> This email has been checked for viruses by AVG. >> https://www.avg.com >> >> >> ___ >> time-nuts mailing list -- time-nuts@lists.febo.com >> To unsubscribe, go to >> http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com >> and follow the instructions there. > > > ___ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. > > > ___ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Isolated +20V for lamp supply
Luciano, You should "Ohm out" the lamp connector shield to the chassis with nothing connected to the connector. Depending on how your optical unit is mounted there is a good chance the lamp assy is grounded to the chassis through the threaded stud! Especially so if the optical is the newer unpainted one. If so isolating it as you detailed does not change anything! Cheers, Corby ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
[time-nuts] Austron Model 2021L Loop Antenna For sale
I have an unused LORAN loop antenna that's been sitting in my garage for years. Contact me at k...@arrl.net for details. Julian KR5J ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] ! PPS Source
IIRC the Thunderbolt DOES lock its internal clock to the GPS David -Original Message- From: time-nuts [mailto:time-nuts-boun...@lists.febo.com] On Behalf Of Bob kb8tq Sent: 13 August 2020 14:39 To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] ! PPS Source Hi Here’s the “whole story”, sorry if it repeats things you already know … All GPS modules that I have ever seen use a free running clock. The internal oscillator is *not* locked to GPS. When they want to generate a 1 pps output they drop / add cycles from the the internal oscillator to get it “as close as possible”. That means that you will always have an error in the PPS. Since they *know* this is going on, many devices report this error on a second by second basis. Since the error looks like a sawtooth if you graph it, this is often called “sawtooth correction”. This correction also takes care of “hanging bridges” where the sawtooth stays to one side or the other of “correct” for a long time. Normally when feeding a PRS-10, the sawtooth correction is not used. That results in a degraded pps accuracy. The best GPS module to use in this case is one with a very small sawtooth “window” ( = a fast internal clock). Right now, the Furuno parts are winning this particular race. If you *do* use the sawtooth correction (possibly by feeding a variable delay line chip), then indeed the F9P and F9T will do a much better job. Some numbers: Sawtooth on some older modules can be out around +/- 20 ns On newer parts it might be down around +/-10 ns. On the F9 parts it is +/-4 ns. The Furuno parts run half that. Corrected, on a modern part, and looking at second to second variation, you can get below 1 ns with various modules. On the F9’s you can get well below 1 ns. = All of that is looking at short term variation. Your Rb does not move much short term (unless the temperature changes …). Its stability and aging likely are quite good. GPS (as received / uncorrected ) swings around a bit during a normal day. Swings of 10 to 20 ns are pretty normal. > 50 ns is possible under odd conditions. That’s more than your Rb is likely to move around over a 4 to 12 hour period. If you “follow” GPS with your Rb through a conventional loop, you likely degrade the stability of the Rb. It takes a fairly fancy loop to do a good job on an Rb. Bob > On Aug 12, 2020, at 11:44 PM, Joe Hobart wrote: > > I have been using 1 PPS from a Motorola M-12 timing module to steer a SRS > PRS-10. I recently heard that a U-Blox ZED F9P module receives both L1 and L2 > and can provide much improved positional accuracy. > > Would better positions translate into a smoother 1 PPS? Does anyone have > experience with this U-Blox module? Can this be set up with a fixed position > as > a timing module? > > Is there a better source of 1 PPS at a reasonable cost? The U-Blox is about > $200. > > Thanks, > Joe, W7LUX > > --- > This email has been checked for viruses by AVG. > https://www.avg.com > > > ___ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] Query about 4060
Jim I am no expert on the FTS units. I have a 4050. But that could indicate 2 possible other answers. The small rise is actually one of the minor lines and you are not hitting the peak. But if you have a gpsdo and match the oscillator to that in open loop then the peak should be right there. Or the second really bad answer. The tube. Many other issues can cause trouble. RF level to the tube Best of luck to you and let us know what you find. Regards Paul On Wed, Aug 12, 2020 at 11:05 PM AC0XU (Jim) wrote: > Time-nuts- > > It has been a couple of years since I last worked on a 4060 so I have > forgotten some of the details. Can someone remind me? > > Operating the device in manual mode, I can adjust beam gain so that I get > a reading. However, ramping the control voltage over its range (which does > sweep the output below and above 10 MHz), the gain needle hardly moves on > the front panel. Measuring with a DVM on test point E26, it does seem that > the voltage increases a bit as I tune through 10 MHz, but the voltage seems > a bit unstable, and the unit won't lock up automatically. > > I am going to check the power supply for open capacitors next. > > Is there anything else I should be checking towards diagnosing the problem? > > Thanks in advance- > > Jim > > > > > > ___ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. > ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] ! PPS Source
Hi Here’s the “whole story”, sorry if it repeats things you already know … All GPS modules that I have ever seen use a free running clock. The internal oscillator is *not* locked to GPS. When they want to generate a 1 pps output they drop / add cycles from the the internal oscillator to get it “as close as possible”. That means that you will always have an error in the PPS. Since they *know* this is going on, many devices report this error on a second by second basis. Since the error looks like a sawtooth if you graph it, this is often called “sawtooth correction”. This correction also takes care of “hanging bridges” where the sawtooth stays to one side or the other of “correct” for a long time. Normally when feeding a PRS-10, the sawtooth correction is not used. That results in a degraded pps accuracy. The best GPS module to use in this case is one with a very small sawtooth “window” ( = a fast internal clock). Right now, the Furuno parts are winning this particular race. If you *do* use the sawtooth correction (possibly by feeding a variable delay line chip), then indeed the F9P and F9T will do a much better job. Some numbers: Sawtooth on some older modules can be out around +/- 20 ns On newer parts it might be down around +/-10 ns. On the F9 parts it is +/-4 ns. The Furuno parts run half that. Corrected, on a modern part, and looking at second to second variation, you can get below 1 ns with various modules. On the F9’s you can get well below 1 ns. = All of that is looking at short term variation. Your Rb does not move much short term (unless the temperature changes …). Its stability and aging likely are quite good. GPS (as received / uncorrected ) swings around a bit during a normal day. Swings of 10 to 20 ns are pretty normal. > 50 ns is possible under odd conditions. That’s more than your Rb is likely to move around over a 4 to 12 hour period. If you “follow” GPS with your Rb through a conventional loop, you likely degrade the stability of the Rb. It takes a fairly fancy loop to do a good job on an Rb. Bob > On Aug 12, 2020, at 11:44 PM, Joe Hobart wrote: > > I have been using 1 PPS from a Motorola M-12 timing module to steer a SRS > PRS-10. I recently heard that a U-Blox ZED F9P module receives both L1 and L2 > and can provide much improved positional accuracy. > > Would better positions translate into a smoother 1 PPS? Does anyone have > experience with this U-Blox module? Can this be set up with a fixed position > as > a timing module? > > Is there a better source of 1 PPS at a reasonable cost? The U-Blox is about > $200. > > Thanks, > Joe, W7LUX > > --- > This email has been checked for viruses by AVG. > https://www.avg.com > > > ___ > time-nuts mailing list -- time-nuts@lists.febo.com > To unsubscribe, go to > http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com > and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
