Re: [time-nuts] PLL/GPSDO/etc learning resources for mere mortals

2018-09-04 Thread Hal Murray
hol...@hotmail.com said: > Besides temperature compensation for holdover conditions you should also > include drift compensation for OCXO aging. The Trimble GPSDOs, HP 38xx > and 53xxx GPSDOs, and Oscilloquartz Star-4 do this. Does any of the HP gear have a temperature sensor? If so, how

Re: [time-nuts] Lots of Off Topic discussion,

2018-09-04 Thread Pete Lancashire
One way I like to put it is like you when I start it in ham radio I immediately considered WWV as the answer to everything TimeWise. But for me around about 1975 I worked at General Electric space flight systems. One could say I became a Time nuts then and discovered that what I thought what is a

Re: [time-nuts] Lost GPS lock or 1PPS recently?

2018-09-04 Thread Hal Murray
I'm in Silicon Valley. I'm logging some data from a Z3801A and a KS-24361. I have a poor antenna location. I'm used to the Z3801A dropping into holdover every few days when it can't find any satellites. Less often for the KS-24361. I noticed some strange activity in the past few days. The

Re: [time-nuts] Lost GPS lock or 1PPS recently?

2018-09-04 Thread Scott McGrath
Actually. I have 6... And a large assortment of directional antennas of many flavors LPDA, Horn etc,I have to get out there and find the interfering source. Cable company has been having problems with ‘booster’ amplifiers installed by homeowners to ‘clean up’ noisy DTV signals. So just

Re: [time-nuts] Trimble Thunderbolt Start Up RS-232 Communications Glitch

2018-09-04 Thread Artek Manuals
You using a mother board serial port or a USB adapter? Not all USB/RS232 adapters are created equal. Drivers for brand "X" vs brand "Y"  can make a difference,. I would go down in the lab to see what I have that is currently working but it is at least 5 years old and you wouldn't likely find

Re: [time-nuts] Lost GPS lock or 1PPS recently?

2018-09-04 Thread Graham / KE9H
The following are active GPS NOTAMs. Data Current as of: Tue, 04 Sep 2018 19:16:00 UTC GPS GLOBAL POSITIONING SYSTEM [Back to Top] !GPS 09/009 (KNMH A0020/18) GPS NAV PRN 02 OUT OF SERVICE 1809061455-1809070255 ZAB ALBUQUERQUE (ARTCC),NM. [Back to Top] !GPS 08/259 (KZAB A0367/18) ZAB NAV GPS

[time-nuts] Trimble Thunderbolt Start Up RS-232 Communications Glitch

2018-09-04 Thread skipp via time-nuts
Re: Trimble Thunderbolt Start Up RS-232 Communications Glitch Hello to the Group, Would anyone be able to help provide a bit of insight or experience in dealing with what I call the an initial Trimble Thunderbolt GPSDO RS-232 communications glitch (during initial power on/up). I've noticed

Re: [time-nuts] Lost GPS lock or 1PPS recently?

2018-09-04 Thread Dana Whitlow
Scott & John, Do either of you have any activity by "Light Squared" (or whatever it's now called) in your area. Jamming does not always have to be in-band to be effective. Dana On Tue, Sep 4, 2018 at 1:11 PM Scott McGrath wrote: > My TrueTime DC-XL has lost lock since yesterday as has my

[time-nuts] Lost GPS lock or 1PPS recently?

2018-09-04 Thread John Sloan
Folks: GPS jamming and spoofing isn't really my area of expertise, but it's something I worry about, not just for its impact on geolocation and navigation applications, but also because GPS has become critical as a high precision timing reference in the telecommunications realm, which *is* my

[time-nuts] PLL/GPSDO/etc learning resources for mere mortals

2018-09-04 Thread Mark Sims
Besides temperature compensation for holdover conditions you should also include drift compensation for OCXO aging. The Trimble GPSDOs, HP 38xx and 53xxx GPSDOs, and Oscilloquartz Star-4 do this. Oscilliquartz calls it ATDC (Automatic Temperature and Drift Compensation). For many OCXOs

Re: [time-nuts] PLL/GPSDO/etc learning resources for mere mortals

2018-09-04 Thread Jim Harman
> The challenge seems to me to be how to temperature stabilize the entire DAC chain without putting it all in an oven Hi Forrest, Generally you don't have to temperature stabilize the DAC because it is inside the phase-locked control loop and the loop will adjust for temperature dependencies,

Re: [time-nuts] PLL/GPSDO/etc learning resources for mere mortals

2018-09-04 Thread Forrest Christian (List Account)
Thanks to everyone who has responded so far. My underlying interest is learning about 1PPS holdover methodologies in the presence of environmental changes (think outdoor day/night temperature cycles). My thoughts are that there are two ways that seem obvious to me to implement a