Re: [time-nuts] Effects of Simple GPS jamming on GPSDO's ?
On Sat, Sep 1, 2018 at 3:49 AM, Dana Whitlow wrote: > > Question for Mark re metal foil under the antenna: > > What's the nature of the improvement? Between the large tilt angle and the > shape of the > foil piece, I'd certainly not expect any material improvement in the > multi-path department. It's just a ground plane. Having a ground plane under the antenna improved signal strength by 5-10 dB over just putting the antenna in the window. I covered a box to get the antenna up a little higher and to have the ground plane be bigger than 1/4 wave at the L1 frequency. It's ugly but it works. It's for a Trueposition GPSDO, not that sensitive. Mounting the antenna inside did not work well. I've also been known to hold my phone in the upper corner of the balcony on a cruise ship to use it as a corner reflector to catch wifi from shops on the dock. That worked surprisingly well too. > > Also, are the Venetian blinds seen in the photo made of metal, or plastic > (or wood)? > Is there a screen on the window? If so, ditto question regarding the > composition. > The blinds are metal. There is no screen in the window, which also made a huge improvement over windows with metal screens. Regards, Mark ___ 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] Effects of Simple GPS jamming on GPSDO's ?
On Fri, Aug 31, 2018 at 12:41 PM, Gerhard Hoffmann wrote: > > >> So you can test your hold over behavior with aluminum foil (or your hand) >> over your antenna >> >> OMG, I first read "with aluminium foil hat over your head" > Now, foil under the antenna on the other hand, big improvement! Regards, Mark ___ 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] Effects of Simple GPS jamming on GPSDO's ?
Hi Time is not (ultimately) determined by an atomic clock. It’s determined by astronomical observations that evaluate the rotation of the planet. Those observations are what drive things like leap seconds. In the event that a flare takes out 99% of all life on earth and every electrical device …. I don’t really think we will be worried about it being 12:01:01 PM. What we *will* be concerned about is not really a Time Nut subject. To answer the question of how many clocks are there - take a look at how UTC is determined by BIH Paris. The answer is in the “many hundreds”. Yes, 99% of them could go along with all the people that run them. Again … not really a Time Nut subject. That still leaves quite a few to run off of. Bob > On Aug 31, 2018, at 6:38 PM, Dana Whitlow wrote: > > I'm thinking about if/when "the big one hits" and takes out most or all of > the GPS > sats, cell phone systems, etc. > > Then the time required to reboot up to a reasonable level of technology > might turn > out to be limited by our ability to determine time and freq somewhat > accurately. The > better we can do from scratch, the faster the reboot. > > So one question is: how many Cs beam clocks are out there which are kept > running > and "on time", at least by frequent logging of errors if not by actual > setting/tweaking? > > If "the big one" is global nuclear war, of course we'll all have far more > to worry about > than keeping our watches accurately set. But what if it's another > Carrington-level > event? I'm sure we'd all like to get back to business as usual as quickly > as possible. > > Dana > > > On Fri, Aug 31, 2018 at 5:23 PM Bob kb8tq wrote: > >> Hi >> >> I think we have a little bit of confusion here. WWVB is not going to help >> anybody navigate. >> It’s not going to help track people with ankle bracelets or trucks >> stopping at bars. Car thieves >> jamming Lojack still happens. Turn iWWVB on or off, this stuff still goes >> on. None of this is >> a Time Nuts sort of issue. >> >> The only thing WWVB *might* do is provide timing. That’s very different >> than navigation. A >> mobile this or that driving by puts your GPSDO into holdover. It maintains >> time while it is in >> holdover. Minutes or hours, possibly days … works the same way. The system >> keeps running >> just like GPS was doing fine. If after a day or more, the GPS is still >> jammed, that single cell tower >> shuts down. Take out one cell tower and the system keeps running. There is >> a lot of overlap on >> these systems. Towers go down a lot more often than you might think ….. >> >> Do all systems work identically in terms of timing? Of course not. If >> timing is critical to operation, >> systems do use GPSDO’s. The same basic principles apply. The main question >> would be one >> of overlap between elements of the system. >> >> The same jamming that takes out GPS for timing also takes it out for >> normal navigation. Take >> it out over an entire city and everybody’s vehicle navigation system goes >> out. Do that even for >> a couple of hours and it’s on the evening news. Do that for a day and >> there *is* a response. >> That’s the kind of thing needed to impact utility systems (like cell >> towers) in a significant way. >> It simply does not happen ….City wide is very hard to do from the ground. >> From the air, you >> can get the coverage. It’s tough to keep doing it from the air for days on >> end. >> >> So, interns of “the world ends if / when WWVB turns off” … not so much. >> >> In terms of the initial question, GPSDO’s in general are pretty good at >> handling the typical >> jamming they might run into. >> >> Bob >> >> >> >>> On Aug 31, 2018, at 3:52 PM, Scott McGrath wrote: >>> >>> And here is one of the schematics running around the ‘net. This one is >> noise based >>> >>> >>> >>> >>> >>> On Aug 31, 2018, at 3:41 PM, Gerhard Hoffmann wrote: >>> >>> >>> Am 31.08.2018 um 19:39 schrieb jimlux: > On 8/31/18 10:15 AM, Bob kb8tq wrote: > Hi > > Having spent a lot of my life designing GPSDO’s it’s a “that depends” >> sort of thing. > For a simple noise jammer, yes, they pretty much all will go into >> holdover. When the > jammer goes away, they come out of holdover. There are a few older >> units that may not > do quite as well with various sorts of broadband jamming. With a >> spoofing jammer that is flying > around overhead and simulating an entire constellation … you could see >> any of them do odd > things. An airborne jammer flying over this or that city likely gets >> you into a “act of war” sort of issue. > It’s something you build if you are a nation state. > > The performance with noise jammers is not a guess. It’s based on field >> experience and > all those never ending meetings I keep referring to ….. > >>> IIRC, there was a truck driver who successfully jammed all those >> airworthy GPS systems >>> at SF airport
Re: [time-nuts] Effects of Simple GPS jamming on GPSDO's ?
That’s the scenario i’m most concerned with not war or terrorism but a natural event which has occurred before and will occur again. Rebooting technology will be a heck of a lot easier with a variety of precision time/frequency distribution methods. After a Carrington type event a working Cs or Rb will be worth several times their weight in gold. Its not that I’m nostalgic for the old days but having a HF frequency source will allow HF networks to determine propagation . Content by Scott Typos by Siri On Aug 31, 2018, at 6:38 PM, Dana Whitlow wrote: I'm thinking about if/when "the big one hits" and takes out most or all of the GPS sats, cell phone systems, etc. Then the time required to reboot up to a reasonable level of technology might turn out to be limited by our ability to determine time and freq somewhat accurately. The better we can do from scratch, the faster the reboot. So one question is: how many Cs beam clocks are out there which are kept running and "on time", at least by frequent logging of errors if not by actual setting/tweaking? If "the big one" is global nuclear war, of course we'll all have far more to worry about than keeping our watches accurately set. But what if it's another Carrington-level event? I'm sure we'd all like to get back to business as usual as quickly as possible. Dana > On Fri, Aug 31, 2018 at 5:23 PM Bob kb8tq wrote: > > Hi > > I think we have a little bit of confusion here. WWVB is not going to help > anybody navigate. > It’s not going to help track people with ankle bracelets or trucks > stopping at bars. Car thieves > jamming Lojack still happens. Turn iWWVB on or off, this stuff still goes > on. None of this is > a Time Nuts sort of issue. > > The only thing WWVB *might* do is provide timing. That’s very different > than navigation. A > mobile this or that driving by puts your GPSDO into holdover. It maintains > time while it is in > holdover. Minutes or hours, possibly days … works the same way. The system > keeps running > just like GPS was doing fine. If after a day or more, the GPS is still > jammed, that single cell tower > shuts down. Take out one cell tower and the system keeps running. There is > a lot of overlap on > these systems. Towers go down a lot more often than you might think ….. > > Do all systems work identically in terms of timing? Of course not. If > timing is critical to operation, > systems do use GPSDO’s. The same basic principles apply. The main question > would be one > of overlap between elements of the system. > > The same jamming that takes out GPS for timing also takes it out for > normal navigation. Take > it out over an entire city and everybody’s vehicle navigation system goes > out. Do that even for > a couple of hours and it’s on the evening news. Do that for a day and > there *is* a response. > That’s the kind of thing needed to impact utility systems (like cell > towers) in a significant way. > It simply does not happen ….City wide is very hard to do from the ground. > From the air, you > can get the coverage. It’s tough to keep doing it from the air for days on > end. > > So, interns of “the world ends if / when WWVB turns off” … not so much. > > In terms of the initial question, GPSDO’s in general are pretty good at > handling the typical > jamming they might run into. > > Bob > > > >> On Aug 31, 2018, at 3:52 PM, Scott McGrath wrote: >> >> And here is one of the schematics running around the ‘net. This one is > noise based >> >> >> >> >> >> On Aug 31, 2018, at 3:41 PM, Gerhard Hoffmann wrote: >> >> >> Am 31.08.2018 um 19:39 schrieb jimlux: On 8/31/18 10:15 AM, Bob kb8tq wrote: Hi Having spent a lot of my life designing GPSDO’s it’s a “that depends” > sort of thing. For a simple noise jammer, yes, they pretty much all will go into > holdover. When the jammer goes away, they come out of holdover. There are a few older > units that may not do quite as well with various sorts of broadband jamming. With a > spoofing jammer that is flying around overhead and simulating an entire constellation … you could see > any of them do odd things. An airborne jammer flying over this or that city likely gets > you into a “act of war” sort of issue. It’s something you build if you are a nation state. The performance with noise jammers is not a guess. It’s based on field > experience and all those never ending meetings I keep referring to ….. >> IIRC, there was a truck driver who successfully jammed all those > airworthy GPS systems >> at SF airport trying to hide his private detours, just by passing on the > highway with >> El Cheapo hardware. >> >>> >>> In effect, a broadband jammer (or, probably, a tone jammer that > overwhelms the 1 bit ADC receiver) is the same as a "loss of signal" - the > receiver probably doesn't know the difference - it just drops sync and > tries to unsuccessfully reacquire. >> >> I think
Re: [time-nuts] Effects of Simple GPS jamming on GPSDO's ?
I'm thinking about if/when "the big one hits" and takes out most or all of the GPS sats, cell phone systems, etc. Then the time required to reboot up to a reasonable level of technology might turn out to be limited by our ability to determine time and freq somewhat accurately. The better we can do from scratch, the faster the reboot. So one question is: how many Cs beam clocks are out there which are kept running and "on time", at least by frequent logging of errors if not by actual setting/tweaking? If "the big one" is global nuclear war, of course we'll all have far more to worry about than keeping our watches accurately set. But what if it's another Carrington-level event? I'm sure we'd all like to get back to business as usual as quickly as possible. Dana On Fri, Aug 31, 2018 at 5:23 PM Bob kb8tq wrote: > Hi > > I think we have a little bit of confusion here. WWVB is not going to help > anybody navigate. > It’s not going to help track people with ankle bracelets or trucks > stopping at bars. Car thieves > jamming Lojack still happens. Turn iWWVB on or off, this stuff still goes > on. None of this is > a Time Nuts sort of issue. > > The only thing WWVB *might* do is provide timing. That’s very different > than navigation. A > mobile this or that driving by puts your GPSDO into holdover. It maintains > time while it is in > holdover. Minutes or hours, possibly days … works the same way. The system > keeps running > just like GPS was doing fine. If after a day or more, the GPS is still > jammed, that single cell tower > shuts down. Take out one cell tower and the system keeps running. There is > a lot of overlap on > these systems. Towers go down a lot more often than you might think ….. > > Do all systems work identically in terms of timing? Of course not. If > timing is critical to operation, > systems do use GPSDO’s. The same basic principles apply. The main question > would be one > of overlap between elements of the system. > > The same jamming that takes out GPS for timing also takes it out for > normal navigation. Take > it out over an entire city and everybody’s vehicle navigation system goes > out. Do that even for > a couple of hours and it’s on the evening news. Do that for a day and > there *is* a response. > That’s the kind of thing needed to impact utility systems (like cell > towers) in a significant way. > It simply does not happen ….City wide is very hard to do from the ground. > From the air, you > can get the coverage. It’s tough to keep doing it from the air for days on > end. > > So, interns of “the world ends if / when WWVB turns off” … not so much. > > In terms of the initial question, GPSDO’s in general are pretty good at > handling the typical > jamming they might run into. > > Bob > > > > > On Aug 31, 2018, at 3:52 PM, Scott McGrath wrote: > > > > And here is one of the schematics running around the ‘net. This one is > noise based > > > > > > > > > > > > On Aug 31, 2018, at 3:41 PM, Gerhard Hoffmann wrote: > > > > > > > >> Am 31.08.2018 um 19:39 schrieb jimlux: > >>> On 8/31/18 10:15 AM, Bob kb8tq wrote: > >>> Hi > >>> > >>> Having spent a lot of my life designing GPSDO’s it’s a “that depends” > sort of thing. > >>> For a simple noise jammer, yes, they pretty much all will go into > holdover. When the > >>> jammer goes away, they come out of holdover. There are a few older > units that may not > >>> do quite as well with various sorts of broadband jamming. With a > spoofing jammer that is flying > >>> around overhead and simulating an entire constellation … you could see > any of them do odd > >>> things. An airborne jammer flying over this or that city likely gets > you into a “act of war” sort of issue. > >>> It’s something you build if you are a nation state. > >>> > >>> The performance with noise jammers is not a guess. It’s based on field > experience and > >>> all those never ending meetings I keep referring to ….. > >>> > > IIRC, there was a truck driver who successfully jammed all those > airworthy GPS systems > > at SF airport trying to hide his private detours, just by passing on the > highway with > > El Cheapo hardware. > > > >> > >> In effect, a broadband jammer (or, probably, a tone jammer that > overwhelms the 1 bit ADC receiver) is the same as a "loss of signal" - the > receiver probably doesn't know the difference - it just drops sync and > tries to unsuccessfully reacquire. > > > > I think that Holmes wrote somewhere that the easiest way to jam was a > carrier quite close > > to the frequency where the suppressed carrier of the BPSK would be. It > could be weak because > > it would have some processing gain, even if not completely sync to the > rest of the signals. > > The typical 1 or 2 Bit ADC has no chance to see it separated from the > rest. > > > >> > >> So you can test your hold over behavior with aluminum foil (or your > hand) over your antenna > >> > > OMG, I first read "with aluminium foil hat over your head" > > > > Cheers, > >
Re: [time-nuts] Effects of Simple GPS jamming on GPSDO's ?
Hi I think we have a little bit of confusion here. WWVB is not going to help anybody navigate. It’s not going to help track people with ankle bracelets or trucks stopping at bars. Car thieves jamming Lojack still happens. Turn iWWVB on or off, this stuff still goes on. None of this is a Time Nuts sort of issue. The only thing WWVB *might* do is provide timing. That’s very different than navigation. A mobile this or that driving by puts your GPSDO into holdover. It maintains time while it is in holdover. Minutes or hours, possibly days … works the same way. The system keeps running just like GPS was doing fine. If after a day or more, the GPS is still jammed, that single cell tower shuts down. Take out one cell tower and the system keeps running. There is a lot of overlap on these systems. Towers go down a lot more often than you might think ….. Do all systems work identically in terms of timing? Of course not. If timing is critical to operation, systems do use GPSDO’s. The same basic principles apply. The main question would be one of overlap between elements of the system. The same jamming that takes out GPS for timing also takes it out for normal navigation. Take it out over an entire city and everybody’s vehicle navigation system goes out. Do that even for a couple of hours and it’s on the evening news. Do that for a day and there *is* a response. That’s the kind of thing needed to impact utility systems (like cell towers) in a significant way. It simply does not happen ….City wide is very hard to do from the ground. From the air, you can get the coverage. It’s tough to keep doing it from the air for days on end. So, interns of “the world ends if / when WWVB turns off” … not so much. In terms of the initial question, GPSDO’s in general are pretty good at handling the typical jamming they might run into. Bob > On Aug 31, 2018, at 3:52 PM, Scott McGrath wrote: > > And here is one of the schematics running around the ‘net. This one is > noise based > > > > > > On Aug 31, 2018, at 3:41 PM, Gerhard Hoffmann wrote: > > > >> Am 31.08.2018 um 19:39 schrieb jimlux: >>> On 8/31/18 10:15 AM, Bob kb8tq wrote: >>> Hi >>> >>> Having spent a lot of my life designing GPSDO’s it’s a “that depends” sort >>> of thing. >>> For a simple noise jammer, yes, they pretty much all will go into holdover. >>> When the >>> jammer goes away, they come out of holdover. There are a few older units >>> that may not >>> do quite as well with various sorts of broadband jamming. With a spoofing >>> jammer that is flying >>> around overhead and simulating an entire constellation … you could see any >>> of them do odd >>> things. An airborne jammer flying over this or that city likely gets you >>> into a “act of war” sort of issue. >>> It’s something you build if you are a nation state. >>> >>> The performance with noise jammers is not a guess. It’s based on field >>> experience and >>> all those never ending meetings I keep referring to ….. >>> > IIRC, there was a truck driver who successfully jammed all those airworthy > GPS systems > at SF airport trying to hide his private detours, just by passing on the > highway with > El Cheapo hardware. > >> >> In effect, a broadband jammer (or, probably, a tone jammer that overwhelms >> the 1 bit ADC receiver) is the same as a "loss of signal" - the receiver >> probably doesn't know the difference - it just drops sync and tries to >> unsuccessfully reacquire. > > I think that Holmes wrote somewhere that the easiest way to jam was a carrier > quite close > to the frequency where the suppressed carrier of the BPSK would be. It could > be weak because > it would have some processing gain, even if not completely sync to the rest > of the signals. > The typical 1 or 2 Bit ADC has no chance to see it separated from the rest. > >> >> So you can test your hold over behavior with aluminum foil (or your hand) >> over your antenna >> > OMG, I first read "with aluminium foil hat over your head" > > Cheers, > Gerhard > > > ___ > 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] Effects of Simple GPS jamming on GPSDO's ?
Am 31.08.2018 um 19:39 schrieb jimlux: On 8/31/18 10:15 AM, Bob kb8tq wrote: Hi Having spent a lot of my life designing GPSDO’s it’s a “that depends” sort of thing. For a simple noise jammer, yes, they pretty much all will go into holdover. When the jammer goes away, they come out of holdover. There are a few older units that may not do quite as well with various sorts of broadband jamming. With a spoofing jammer that is flying around overhead and simulating an entire constellation … you could see any of them do odd things. An airborne jammer flying over this or that city likely gets you into a “act of war” sort of issue. It’s something you build if you are a nation state. The performance with noise jammers is not a guess. It’s based on field experience and all those never ending meetings I keep referring to ….. IIRC, there was a truck driver who successfully jammed all those airworthy GPS systems at SF airport trying to hide his private detours, just by passing on the highway with El Cheapo hardware. In effect, a broadband jammer (or, probably, a tone jammer that overwhelms the 1 bit ADC receiver) is the same as a "loss of signal" - the receiver probably doesn't know the difference - it just drops sync and tries to unsuccessfully reacquire. I think that Holmes wrote somewhere that the easiest way to jam was a carrier quite close to the frequency where the suppressed carrier of the BPSK would be. It could be weak because it would have some processing gain, even if not completely sync to the rest of the signals. The typical 1 or 2 Bit ADC has no chance to see it separated from the rest. So you can test your hold over behavior with aluminum foil (or your hand) over your antenna OMG, I first read "with aluminium foil hat over your head" Cheers, Gerhard ___ 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] Effects of Simple GPS jamming on GPSDO's ?
Hi Most of them are doing CW signal detection and notch filtering. There are a number of ways for “birdies” to show up in any environment, jamming or no jamming. Some of the details of who’s doing what and how well are under NDA. None of it is 100% effective, it’s just a way to get another 10, 20 or 30 db of margin at this or that offset from carrier. Bob > On Aug 31, 2018, at 1:36 PM, Mark Sims wrote: > > Several GPS receivers have a setting for enabling jamming detection and/or > mitigation. The datasheets don't tend to talk about what it does. But, if > the receiver supports it (Trimble and Venus devices), Lady Heather can > configure it. > ___ > 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] Effects of Simple GPS jamming on GPSDO's ?
On 8/31/18 10:15 AM, Bob kb8tq wrote: Hi Having spent a lot of my life designing GPSDO’s it’s a “that depends” sort of thing. For a simple noise jammer, yes, they pretty much all will go into holdover. When the jammer goes away, they come out of holdover. There are a few older units that may not do quite as well with various sorts of broadband jamming. With a spoofing jammer that is flying around overhead and simulating an entire constellation … you could see any of them do odd things. An airborne jammer flying over this or that city likely gets you into a “act of war” sort of issue. It’s something you build if you are a nation state. The performance with noise jammers is not a guess. It’s based on field experience and all those never ending meetings I keep referring to ….. In effect, a broadband jammer (or, probably, a tone jammer that overwhelms the 1 bit ADC receiver) is the same as a "loss of signal" - the receiver probably doesn't know the difference - it just drops sync and tries to unsuccessfully reacquire. So you can test your hold over behavior with aluminum foil (or your hand) over your antenna ___ 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] Effects of Simple GPS jamming on GPSDO's ?
Several GPS receivers have a setting for enabling jamming detection and/or mitigation. The datasheets don't tend to talk about what it does. But, if the receiver supports it (Trimble and Venus devices), Lady Heather can configure it. ___ 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] Effects of Simple GPS jamming on GPSDO's ?
Hi Having spent a lot of my life designing GPSDO’s it’s a “that depends” sort of thing. For a simple noise jammer, yes, they pretty much all will go into holdover. When the jammer goes away, they come out of holdover. There are a few older units that may not do quite as well with various sorts of broadband jamming. With a spoofing jammer that is flying around overhead and simulating an entire constellation … you could see any of them do odd things. An airborne jammer flying over this or that city likely gets you into a “act of war” sort of issue. It’s something you build if you are a nation state. The performance with noise jammers is not a guess. It’s based on field experience and all those never ending meetings I keep referring to ….. Bob > On Aug 31, 2018, at 12:04 PM, Mark Spencer wrote: > > Hi: > > I'm curious if anyone knows how typical GPSDO's are likely to respond to > simple GPS jammers ? Could the GPSDO be reasonably expected to go into hold > over ? > > The use case I am thinking is along the lines of: > > -A commercial operation relies on a GPSDO for timing at a remote site. > > -A vehicle with a simple GPS jammer (perhaps intended by the vehicle driver > to defeat a GPS tracking system installed near the vehicle) parks near the > GPS antenna. > > I'm thinking one likely outcome is the GPSDO goes into hold over and when the > vehicle moves away it exits hold over ? This is all just speculation on my > part. > > Comments ? > > Thanks > Mark Spencer > > m...@alignedsolutions.com > 604 762 4099 > ___ > 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] Effects of Simple GPS jamming on GPSDO's ?
Hi: I'm curious if anyone knows how typical GPSDO's are likely to respond to simple GPS jammers ? Could the GPSDO be reasonably expected to go into hold over ? The use case I am thinking is along the lines of: -A commercial operation relies on a GPSDO for timing at a remote site. -A vehicle with a simple GPS jammer (perhaps intended by the vehicle driver to defeat a GPS tracking system installed near the vehicle) parks near the GPS antenna. I'm thinking one likely outcome is the GPSDO goes into hold over and when the vehicle moves away it exits hold over ? This is all just speculation on my part. Comments ? Thanks Mark Spencer m...@alignedsolutions.com 604 762 4099 ___ 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.
