Re: [time-nuts] FE-5680A Voltage tolerance
I've had one of mine running on a bench supply for about 2 days now. Have just tried turning the voltage down, and things started to get unstable at around 12.5V. It didn't drop out of lock however until about 9V. Rob Kimberley -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Peter Gottlieb Sent: 20 January 2012 04:16 To: time-nuts@febo.com Subject: Re: [time-nuts] FE-5680A Voltage tolerance When I got my first unit I hooked it up to my protoboard power supply which is rated at 15 volts 0.5 amps and 5 volts 1 amp. I was annoyed that it took about 10 minutes to lock up until I realized the 15 volt supply was down near 11.5 volts. Oops. Substituting my small BK bench supply (good for up to 3 amps) resulted in a lock in under a couple of minutes. Perhaps my unit's internal adjustments are still just about right. It would be nice to get the alignment procedure for the thing, but I suppose, fat chance of that. Peter On 1/19/2012 6:45 PM, gonzo . wrote: Experiment for the day. I thought I'd follow Dons quote and see how tolerant my unit is. My benchmark is at 15.5V it locks in about 3min. I backed off the supply to 10.8V and the lock time (from cold) is 8min. I thought this was interesting given several people report they are unable to get a lock when running lower voltage. ian ___ 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. - No virus found in this message. Checked by AVG - www.avg.com Version: 10.0.1416 / Virus Database: 2109/4754 - Release Date: 01/19/12 ___ 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] FE-5680A Voltage tolerance
On Thu, 19 Jan 2012 16:29:35 -0800, Chris Albertson wrote: Could also be the all theses FE5680s don't have the same design. Already we've seen some don' have 5V regulators possably they changed the 15v side at some point? Chris Albertson Redondo Beach, California Besides the 2 cheap FE5680s i have (the ones that need 15v 5v) I have a FE5680 ($100+) that needs only 15v , this one has a PIC a DDS inside. The PIC can accept commands via rs232 , and then programs the DDS. It is supposedly adjustable in frequency from ?? to 20Mhz. CFO ___ 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] FE-5680A Voltage tolerance
It is not surprising that many of these units work alright below their specified voltage. I would imagine that the internal regulators, in addition to dropping voltage, are also there to keep voltages stable, and thus help with unit stability. So, a unit may work fine, and be able to meet stability specs, when operated slightly below the 15 volts, PROVIDED that that lower input voltage is provided by a stable, regulated supply. If I were the manufacturer, I would not want to have to rely on the supply being perfect, I would want to do my own regulation as they have. These are used in a system where the power supply drives many items and there are voltage drops due to wiring, backplanes, traces, etc as well as variations due to load changes. You may be able to have one unit work fine slightly below spec'd voltage, but if you do that in a system or with an unregulated supply and all bets are off. Give the unit decent power within its specified input range and then that's one thing you don't have to worry about further. Peter On 1/20/2012 6:09 AM, Rob Kimberley wrote: I've had one of mine running on a bench supply for about 2 days now. Have just tried turning the voltage down, and things started to get unstable at around 12.5V. It didn't drop out of lock however until about 9V. Rob Kimberley -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Peter Gottlieb Sent: 20 January 2012 04:16 To: time-nuts@febo.com Subject: Re: [time-nuts] FE-5680A Voltage tolerance When I got my first unit I hooked it up to my protoboard power supply which is rated at 15 volts 0.5 amps and 5 volts 1 amp. I was annoyed that it took about 10 minutes to lock up until I realized the 15 volt supply was down near 11.5 volts. Oops. Substituting my small BK bench supply (good for up to 3 amps) resulted in a lock in under a couple of minutes. Perhaps my unit's internal adjustments are still just about right. It would be nice to get the alignment procedure for the thing, but I suppose, fat chance of that. Peter On 1/19/2012 6:45 PM, gonzo . wrote: Experiment for the day. I thought I'd follow Dons quote and see how tolerant my unit is. My benchmark is at 15.5V it locks in about 3min. I backed off the supply to 10.8V and the lock time (from cold) is 8min. I thought this was interesting given several people report they are unable to get a lock when running lower voltage. ian ___ 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. - No virus found in this message. Checked by AVG - www.avg.com Version: 10.0.1416 / Virus Database: 2109/4754 - Release Date: 01/19/12 ___ 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. - No virus found in this message. Checked by AVG - www.avg.com Version: 10.0.1416 / Virus Database: 2109/4754 - Release Date: 01/19/12 ___ 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] FE-5680A Voltage tolerance
Starting Sunday I will do some voltage tests, giving up on aging test, nine weeks is long enough. I will se if the next one is as good, how ever I do not understand all the talk about running it at a lower voltage. Loosing regulation will definitely impact performance. I have not analysed my unit but a 13.3 V LDO was reported. In my opinion that says what the lower limit is based on sufficient margin for that regulator. What is wrong with 15 Volt? I am running the unit right out of the switcher no extra filtering and I can say based on my tests that it is good to 1 E-12. I also se a 4 Hz loop that will be there with any kind of regulation. That is why I will include a clean up OCXO with a 100 second analog filter. That OCXO will get special attention in its supply voltage regulation. Starting out with 15 Volt gives me enough head room. I am using a $ 10 12 V 2 A switcher cranked up to 15 V. Bert Kehren In a message dated 1/20/2012 7:43:16 A.M. Eastern Standard Time, n...@verizon.net writes: It is not surprising that many of these units work alright below their specified voltage. I would imagine that the internal regulators, in addition to dropping voltage, are also there to keep voltages stable, and thus help with unit stability. So, a unit may work fine, and be able to meet stability specs, when operated slightly below the 15 volts, PROVIDED that that lower input voltage is provided by a stable, regulated supply. If I were the manufacturer, I would not want to have to rely on the supply being perfect, I would want to do my own regulation as they have. These are used in a system where the power supply drives many items and there are voltage drops due to wiring, backplanes, traces, etc as well as variations due to load changes. You may be able to have one unit work fine slightly below spec'd voltage, but if you do that in a system or with an unregulated supply and all bets are off. Give the unit decent power within its specified input range and then that's one thing you don't have to worry about further. Peter On 1/20/2012 6:09 AM, Rob Kimberley wrote: I've had one of mine running on a bench supply for about 2 days now. Have just tried turning the voltage down, and things started to get unstable at around 12.5V. It didn't drop out of lock however until about 9V. Rob Kimberley -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Peter Gottlieb Sent: 20 January 2012 04:16 To: time-nuts@febo.com Subject: Re: [time-nuts] FE-5680A Voltage tolerance When I got my first unit I hooked it up to my protoboard power supply which is rated at 15 volts 0.5 amps and 5 volts 1 amp. I was annoyed that it took about 10 minutes to lock up until I realized the 15 volt supply was down near 11.5 volts. Oops. Substituting my small BK bench supply (good for up to 3 amps) resulted in a lock in under a couple of minutes. Perhaps my unit's internal adjustments are still just about right. It would be nice to get the alignment procedure for the thing, but I suppose, fat chance of that. Peter On 1/19/2012 6:45 PM, gonzo . wrote: Experiment for the day. I thought I'd follow Dons quote and see how tolerant my unit is. My benchmark is at 15.5V it locks in about 3min. I backed off the supply to 10.8V and the lock time (from cold) is 8min. I thought this was interesting given several people report they are unable to get a lock when running lower voltage. ian ___ 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. - No virus found in this message. Checked by AVG - www.avg.com Version: 10.0.1416 / Virus Database: 2109/4754 - Release Date: 01/19/12 ___ 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. - No virus found in this message. Checked by AVG - www.avg.com Version: 10.0.1416 / Virus Database: 2109/4754 - Release Date: 01/19/12 ___ 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] FE-5680A Voltage tolerance
Hi I think there are two somewhat independent things flowing through this thread. The first is - what is the real minimum voltage for this or that level of operation. The second is - what is the voltage for *best* operation. Every time I've been down this road before with an Rb, the answer to what's best has been a well regulated supply at the minimum specified input voltage. Varying the supply always seems to impact something and regulating supplies is easy these days. Bob -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of ewkeh...@aol.com Sent: Friday, January 20, 2012 8:01 AM To: time-nuts@febo.com Subject: Re: [time-nuts] FE-5680A Voltage tolerance Starting Sunday I will do some voltage tests, giving up on aging test, nine weeks is long enough. I will se if the next one is as good, how ever I do not understand all the talk about running it at a lower voltage. Loosing regulation will definitely impact performance. I have not analysed my unit but a 13.3 V LDO was reported. In my opinion that says what the lower limit is based on sufficient margin for that regulator. What is wrong with 15 Volt? I am running the unit right out of the switcher no extra filtering and I can say based on my tests that it is good to 1 E-12. I also se a 4 Hz loop that will be there with any kind of regulation. That is why I will include a clean up OCXO with a 100 second analog filter. That OCXO will get special attention in its supply voltage regulation. Starting out with 15 Volt gives me enough head room. I am using a $ 10 12 V 2 A switcher cranked up to 15 V. Bert Kehren In a message dated 1/20/2012 7:43:16 A.M. Eastern Standard Time, n...@verizon.net writes: It is not surprising that many of these units work alright below their specified voltage. I would imagine that the internal regulators, in addition to dropping voltage, are also there to keep voltages stable, and thus help with unit stability. So, a unit may work fine, and be able to meet stability specs, when operated slightly below the 15 volts, PROVIDED that that lower input voltage is provided by a stable, regulated supply. If I were the manufacturer, I would not want to have to rely on the supply being perfect, I would want to do my own regulation as they have. These are used in a system where the power supply drives many items and there are voltage drops due to wiring, backplanes, traces, etc as well as variations due to load changes. You may be able to have one unit work fine slightly below spec'd voltage, but if you do that in a system or with an unregulated supply and all bets are off. Give the unit decent power within its specified input range and then that's one thing you don't have to worry about further. Peter On 1/20/2012 6:09 AM, Rob Kimberley wrote: I've had one of mine running on a bench supply for about 2 days now. Have just tried turning the voltage down, and things started to get unstable at around 12.5V. It didn't drop out of lock however until about 9V. Rob Kimberley -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Peter Gottlieb Sent: 20 January 2012 04:16 To: time-nuts@febo.com Subject: Re: [time-nuts] FE-5680A Voltage tolerance When I got my first unit I hooked it up to my protoboard power supply which is rated at 15 volts 0.5 amps and 5 volts 1 amp. I was annoyed that it took about 10 minutes to lock up until I realized the 15 volt supply was down near 11.5 volts. Oops. Substituting my small BK bench supply (good for up to 3 amps) resulted in a lock in under a couple of minutes. Perhaps my unit's internal adjustments are still just about right. It would be nice to get the alignment procedure for the thing, but I suppose, fat chance of that. Peter On 1/19/2012 6:45 PM, gonzo . wrote: Experiment for the day. I thought I'd follow Dons quote and see how tolerant my unit is. My benchmark is at 15.5V it locks in about 3min. I backed off the supply to 10.8V and the lock time (from cold) is 8min. I thought this was interesting given several people report they are unable to get a lock when running lower voltage. ian ___ 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. - No virus found in this message. Checked by AVG - www.avg.com Version: 10.0.1416 / Virus Database: 2109/4754 - Release Date: 01/19/12 ___ 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. - No virus found in this message. Checked by AVG - www.avg.com Version
[time-nuts] FE-5680A Voltage tolerance
Experiment for the day. I thought I'd follow Dons quote and see how tolerant my unit is. My benchmark is at 15.5V it locks in about 3min. I backed off the supply to 10.8V and the lock time (from cold) is 8min. I thought this was interesting given several people report they are unable to get a lock when running lower voltage. ian ___ 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] FE-5680A Voltage tolerance
Very interesting data. I wonder if this has to do with the nominal center frequency of the internal 60 MHz VCXO (which is divided by 6 to generate the 10 MHz output). On my units, the center frequency is pretty low and the 10 MHz output is near the top of the range (actually beyond the range on one unit, so it would never lock, until I tweaked the C217 trimmer). If there's an internal supply rail that sags even slightly, that would probably put at least one of my units out of lock range. Of course there's more to the whole system, maybe the Rb doesn't reach temperature, or the microwave section droops or has inadequate power level, etc. I'd suspect even if the unit does work at very low voltages, it is more marginal, noisy and less stable. It is surprising that it works at all below 11 V input, though. -John Beale From: gonzo . cadbl...@hotmail.com Subject: [time-nuts] FE-5680A Voltage tolerance Experiment for the day. I thought I'd follow Dons quote and see how tolerant my unit is. My benchmark is at 15.5V it locks in about 3min. I backed off the supply to 10.8V and the lock time (from cold) is 8min. ___ 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] FE-5680A Voltage tolerance
On Thu, Jan 19, 2012 at 3:45 PM, gonzo . cadbl...@hotmail.com wrote: Experiment for the day. I thought I'd follow Dons quote and see how tolerant my unit is. My benchmark is at 15.5V it locks in about 3min. I backed off the supply to 10.8V and the lock time (from cold) is 8min. It looks like I simply gave up to soon. I waited about double the normal time for lock and assumed it would never happen. I figured there must be a regulator inside and I was below its drop out range. Could also be the all theses FE5680s don't have the same design. Already we've seen some don' have 5V regulators possably they changed the 15v side at some point? Chris Albertson Redondo Beach, California ___ 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] FE-5680A Voltage tolerance
I would expect the RF circuitry to handle a lower voltage without too much trouble. However, a lower input voltage means it will take longer for the ovens to come up to temperature. Until they stabilize, a lock probably won't happen. Once the unit has warmed up and locked, how low can you go and still maintain lock? As you drop the voltage, the ovens will run closer to full on. Once you reach the point where one or more of the ovens are full on, further voltage reduction will quickly cause issues. Ed On 1/19/2012 5:45 PM, gonzo . wrote: Experiment for the day. I thought I'd follow Dons quote and see how tolerant my unit is. My benchmark is at 15.5V it locks in about 3min. I backed off the supply to 10.8V and the lock time (from cold) is 8min. I thought this was interesting given several people report they are unable to get a lock when running lower voltage. ian ___ 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] FE-5680A Voltage tolerance
As soon as my next unit comes in I will run some controlled tests. This one refuses to show aging with week 9 up in two days. I will use it for other tests before I take it appart. Bert In a message dated 1/19/2012 8:18:10 P.M. Eastern Standard Time, ed_pal...@sasktel.net writes: I would expect the RF circuitry to handle a lower voltage without too much trouble. However, a lower input voltage means it will take longer for the ovens to come up to temperature. Until they stabilize, a lock probably won't happen. Once the unit has warmed up and locked, how low can you go and still maintain lock? As you drop the voltage, the ovens will run closer to full on. Once you reach the point where one or more of the ovens are full on, further voltage reduction will quickly cause issues. Ed On 1/19/2012 5:45 PM, gonzo . wrote: Experiment for the day. I thought I'd follow Dons quote and see how tolerant my unit is. My benchmark is at 15.5V it locks in about 3min. I backed off the supply to 10.8V and the lock time (from cold) is 8min. I thought this was interesting given several people report they are unable to get a lock when running lower voltage. ian ___ 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] FE-5680A Voltage tolerance
Speaking of aging, can anyone explain FEI's spec for aging on the 5680A? 2e-11 per DAY? Seriously? Everyone else specs their Rb standards in the Xe-11 range per MONTH. When I first saw it, I thought it was just a typo, but it's in multiple documents and web pages and it's been there for years. Ed On 1/19/2012 7:35 PM, ewkeh...@aol.com wrote: As soon as my next unit comes in I will run some controlled tests. This one refuses to show aging with week 9 up in two days. I will use it for other tests before I take it appart. Bert In a message dated 1/19/2012 8:18:10 P.M. Eastern Standard Time, ed_pal...@sasktel.net writes: I would expect the RF circuitry to handle a lower voltage without too much trouble. However, a lower input voltage means it will take longer for the ovens to come up to temperature. Until they stabilize, a lock probably won't happen. Once the unit has warmed up and locked, how low can you go and still maintain lock? As you drop the voltage, the ovens will run closer to full on. Once you reach the point where one or more of the ovens are full on, further voltage reduction will quickly cause issues. Ed On 1/19/2012 5:45 PM, gonzo . wrote: Experiment for the day. I thought I'd follow Dons quote and see how tolerant my unit is. My benchmark is at 15.5V it locks in about 3min. I backed off the supply to 10.8V and the lock time (from cold) is 8min. I thought this was interesting given several people report they are unable to get a lock when running lower voltage. ian ___ 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] FE-5680A Voltage tolerance
When I got my first unit I hooked it up to my protoboard power supply which is rated at 15 volts 0.5 amps and 5 volts 1 amp. I was annoyed that it took about 10 minutes to lock up until I realized the 15 volt supply was down near 11.5 volts. Oops. Substituting my small BK bench supply (good for up to 3 amps) resulted in a lock in under a couple of minutes. Perhaps my unit's internal adjustments are still just about right. It would be nice to get the alignment procedure for the thing, but I suppose, fat chance of that. Peter On 1/19/2012 6:45 PM, gonzo . wrote: Experiment for the day. I thought I'd follow Dons quote and see how tolerant my unit is. My benchmark is at 15.5V it locks in about 3min. I backed off the supply to 10.8V and the lock time (from cold) is 8min. I thought this was interesting given several people report they are unable to get a lock when running lower voltage. ian ___ 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. - No virus found in this message. Checked by AVG - www.avg.com Version: 10.0.1416 / Virus Database: 2109/4754 - Release Date: 01/19/12 ___ 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.
