Re: [time-nuts] 10 MHz 'failover' switch?
Hi Bob, Thanks for the quick reply, makes sense. 73 Scott W7SLS > On Jul 26, 2018, at 1:13 PM, Bob kb8tq wrote: > > Hi > > They are a pretty rare item. A more common approach is a disciplined > oscillator that > will do failover on it’s inputs. That’s still a rare item, but at least a > possible thing to find. > The equally big problem will be getting doc’s on one if you do find it…. > > Bob > >> On Jul 26, 2018, at 2:45 PM, W7SLS wrote: >> >> Hello, >> >> Looking for recommendation for a ‘failover’ or ‘redundant’ switch for 10 MHz >> distribution. >> >> Not really sure of the correct term. >> Something that sensed RF on primary 10 MHz, and then switched to >> secondary on fail of primary. >> >> A brief search showed several very nice $$$ items, suitable for commercial >> applications, >> but I wonder if there are some “last year’s” (but not last century) versions >> that would work for a home lab. >> >> Context: >> >> I have a GPSDO and a Rb source of 10 MHz. >> The power supply on the GPSDO failed (worked enough to light up the GPSDO, >> but not enough to lock). >> I have a new power supply on order, but would be nice to have “insurance”. >> >> Thanks in advance for the group bandwidth. >> >> Scott >> W7SLS ___ 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] 10 MHz 'failover' switch?
Hi 90 db will not drive the ADEV nuts, but it still will be a lot worse than a normal standard will deliver, even at 120 db down, if the offset is a bit above 1 Hz you will still see it in an ADEV plot. Bob > On Jul 26, 2018, at 5:40 PM, Scott McGrath wrote: > > True but if you use a good switch or PIN 90 db of isolation is easily > achievable. Yes the spur is still there but it’s 90 down and will not > affect ADEV as badly. > > You could drive it further down with two switches with the alternate standard > connected to 1 port and a termination to the other. So a switchover would > switch to the alternate port and the backup path would switch from > termination to backup source.This would easily buy you 120-130 db > isolation assuming use of good cabling and proper routing, grounds etc > > After all this IS time-nuts after all > > Content by Scott > Typos by Siri > > On Jul 26, 2018, at 6:23 PM, Van Horn, David > wrote: > > Not quite what you are looking for, but I implemented a pair of thunderbolts > with no common parts (dual antennas power etc) into a simple RF switch. > The production manager flipped the switch on Mondays, and if either system > wasn't working I had a third system in a box ready to replace. > So for any failure of the two live systems, all he had to do was flip the > switch and call me. > > > -Original Message- > From: time-nuts On Behalf Of W7SLS > Sent: Thursday, July 26, 2018 1:46 PM > To: time-nuts@lists.febo.com > Subject: [time-nuts] 10 MHz 'failover' switch? > > Hello, > > Looking for recommendation for a ‘failover’ or ‘redundant’ switch for 10 MHz > distribution. > > Not really sure of the correct term. > Something that sensed RF on primary 10 MHz, and then switched to secondary > on fail of primary. > > A brief search showed several very nice $$$ items, suitable for commercial > applications, but I wonder if there are some “last year’s” (but not last > century) versions that would work for a home lab. > > Context: > > I have a GPSDO and a Rb source of 10 MHz. > The power supply on the GPSDO failed (worked enough to light up the GPSDO, > but not enough to lock). > I have a new power supply on order, but would be nice to have “insurance”. > > Thanks in advance for the group bandwidth. > > Scott > W7SLS > ___ > 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] 10 MHz 'failover' switch?
On Thu, July 26, 2018 5:05 pm, Hal Murray wrote: > Has anybody built a microprocessor controlled PLL to handle this case? There are failover clock generators (integrated circuits), typically marketed for use in telecom equipment where there is a requirement to synchronize with a reference clock if it is available, and if the reference clock is not available for some reason flag an alarm and continue running from a local oscillator. As pointed out, not necessarily "time-nuts" quality of close in phase noise and ADEV performance, but you can do handy things like have controlled slew on the output of the PLL so that there is no sudden phase jump when the reference clock goes away. -- Chris Caudle ___ 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] 10 MHz 'failover' switch?
True but if you use a good switch or PIN 90 db of isolation is easily achievable. Yes the spur is still there but it’s 90 down and will not affect ADEV as badly. You could drive it further down with two switches with the alternate standard connected to 1 port and a termination to the other. So a switchover would switch to the alternate port and the backup path would switch from termination to backup source.This would easily buy you 120-130 db isolation assuming use of good cabling and proper routing, grounds etc After all this IS time-nuts after all Content by Scott Typos by Siri On Jul 26, 2018, at 6:23 PM, Van Horn, David wrote: Not quite what you are looking for, but I implemented a pair of thunderbolts with no common parts (dual antennas power etc) into a simple RF switch. The production manager flipped the switch on Mondays, and if either system wasn't working I had a third system in a box ready to replace. So for any failure of the two live systems, all he had to do was flip the switch and call me. -Original Message- From: time-nuts On Behalf Of W7SLS Sent: Thursday, July 26, 2018 1:46 PM To: time-nuts@lists.febo.com Subject: [time-nuts] 10 MHz 'failover' switch? Hello, Looking for recommendation for a ‘failover’ or ‘redundant’ switch for 10 MHz distribution. Not really sure of the correct term. Something that sensed RF on primary 10 MHz, and then switched to secondary on fail of primary. A brief search showed several very nice $$$ items, suitable for commercial applications, but I wonder if there are some “last year’s” (but not last century) versions that would work for a home lab. Context: I have a GPSDO and a Rb source of 10 MHz. The power supply on the GPSDO failed (worked enough to light up the GPSDO, but not enough to lock). I have a new power supply on order, but would be nice to have “insurance”. Thanks in advance for the group bandwidth. Scott W7SLS ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there. ___ time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe, go to http://lists.febo.com/mailman/listinfo/time-nuts_lists.febo.com and follow the instructions there.
Re: [time-nuts] 10 MHz 'failover' switch?
Not quite what you are looking for, but I implemented a pair of thunderbolts with no common parts (dual antennas power etc) into a simple RF switch. The production manager flipped the switch on Mondays, and if either system wasn't working I had a third system in a box ready to replace. So for any failure of the two live systems, all he had to do was flip the switch and call me. -Original Message- From: time-nuts On Behalf Of W7SLS Sent: Thursday, July 26, 2018 1:46 PM To: time-nuts@lists.febo.com Subject: [time-nuts] 10 MHz 'failover' switch? Hello, Looking for recommendation for a ‘failover’ or ‘redundant’ switch for 10 MHz distribution. Not really sure of the correct term. Something that sensed RF on primary 10 MHz, and then switched to secondary on fail of primary. A brief search showed several very nice $$$ items, suitable for commercial applications, but I wonder if there are some “last year’s” (but not last century) versions that would work for a home lab. Context: I have a GPSDO and a Rb source of 10 MHz. The power supply on the GPSDO failed (worked enough to light up the GPSDO, but not enough to lock). I have a new power supply on order, but would be nice to have “insurance”. Thanks in advance for the group bandwidth. Scott W7SLS ___ 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] 10 MHz 'failover' switch?
kb...@n1k.org said: > One interesting subtlety making something like this: > What if the two inputs arenât quite on the same frequency? Purely as an > example, say they are 1 Hz off from each other. If you have 60 db of > isolation in your âswitchâ you get a 1 Hz offset spur that is 60 db down. > Even something much further down is plenty to mess up the ADEV of the > output. Has anybody built a microprocessor controlled PLL to handle this case? If you have the microprocessor and DAC, watching a second input and switching in software doesn't seem like a big step. - Can I put two switches in series? The is-it-working logic has to be look before the first switch, but the first switch is on-off rather than A-B. It can be in a separate package placed to minimize feed-through. -- 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] 10 MHz 'failover' switch?
Hi One interesting subtlety making something like this: What if the two inputs aren’t quite on the same frequency? Purely as an example, say they are 1 Hz off from each other. If you have 60 db of isolation in your “switch” you get a 1 Hz offset spur that is 60 db down. Even something much further down is plenty to mess up the ADEV of the output. Bob > On Jul 26, 2018, at 4:33 PM, Scott McGrath wrote: > > Build one yourself, Detector diode on primary RF input when output drops > use a rf relay or PIN diode switch to fail over to backup standard.All > thats needed is a crossing detector and relay / switch driver > > Yes there would be a momentary hit but it would work. > > Content by Scott > Typos by Siri > > On Jul 26, 2018, at 4:13 PM, Bob kb8tq wrote: > > Hi > > They are a pretty rare item. A more common approach is a disciplined > oscillator that > will do failover on it’s inputs. That’s still a rare item, but at least a > possible thing to find. > The equally big problem will be getting doc’s on one if you do find it…. > > Bob > >> On Jul 26, 2018, at 2:45 PM, W7SLS wrote: >> >> Hello, >> >> Looking for recommendation for a ‘failover’ or ‘redundant’ switch for 10 MHz >> distribution. >> >> Not really sure of the correct term. >> Something that sensed RF on primary 10 MHz, and then switched to secondary >> on fail of primary. >> >> A brief search showed several very nice $$$ items, suitable for commercial >> applications, >> but I wonder if there are some “last year’s” (but not last century) versions >> that would work for a home lab. >> >> Context: >> >> I have a GPSDO and a Rb source of 10 MHz. >> The power supply on the GPSDO failed (worked enough to light up the GPSDO, >> but not enough to lock). >> I have a new power supply on order, but would be nice to have “insurance”. >> >> Thanks in advance for the group bandwidth. >> >> Scott >> W7SLS >> ___ >> 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] 10 MHz 'failover' switch?
Build one yourself, Detector diode on primary RF input when output drops use a rf relay or PIN diode switch to fail over to backup standard.All thats needed is a crossing detector and relay / switch driver Yes there would be a momentary hit but it would work. Content by Scott Typos by Siri On Jul 26, 2018, at 4:13 PM, Bob kb8tq wrote: Hi They are a pretty rare item. A more common approach is a disciplined oscillator that will do failover on it’s inputs. That’s still a rare item, but at least a possible thing to find. The equally big problem will be getting doc’s on one if you do find it…. Bob > On Jul 26, 2018, at 2:45 PM, W7SLS wrote: > > Hello, > > Looking for recommendation for a ‘failover’ or ‘redundant’ switch for 10 MHz > distribution. > >Not really sure of the correct term. >Something that sensed RF on primary 10 MHz, and then switched to secondary > on fail of primary. > > A brief search showed several very nice $$$ items, suitable for commercial > applications, > but I wonder if there are some “last year’s” (but not last century) versions > that would work for a home lab. > > Context: > > I have a GPSDO and a Rb source of 10 MHz. > The power supply on the GPSDO failed (worked enough to light up the GPSDO, > but not enough to lock). > I have a new power supply on order, but would be nice to have “insurance”. > > Thanks in advance for the group bandwidth. > > Scott > W7SLS > ___ > 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] 10 MHz 'failover' switch?
Hello, Looking for recommendation for a ‘failover’ or ‘redundant’ switch for 10 MHz distribution. Not really sure of the correct term. Something that sensed RF on primary 10 MHz, and then switched to secondary on fail of primary. A brief search showed several very nice $$$ items, suitable for commercial applications, but I wonder if there are some “last year’s” (but not last century) versions that would work for a home lab. Context: I have a GPSDO and a Rb source of 10 MHz. The power supply on the GPSDO failed (worked enough to light up the GPSDO, but not enough to lock). I have a new power supply on order, but would be nice to have “insurance”. Thanks in advance for the group bandwidth. Scott W7SLS ___ 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.
