Hi Gar: OK. It's time to pull the plug and leave it out for awhile. I tried pulling the plug for 10 seconds, but that may not have been long enough to get the oven cooled down.
More later, Brooke NE8S wrote: >Brooke, > >One of my FTS4060's behaved the same way during a power interrupt. It was >the only one that was not on a UPS. After many attempts to reset the logic >while powered up, I finally brought the clock down and 24 hours later, >powered it back up again. As a result, it performed its normal power-up >sequence and the control logic seemed to have reset itself properly. It this >point, it was back to normal. It has been fine ever since. > >First time it has happened to me. I am mainly an HP man and very much prefer >the HP clocks and their digital logic structure and methods. > >Hope this helps a little. > >Kind regards, > >Gar Ko >NE8S >CsUTC Observatory >Bio-Nucleonics Laboratory > >----- Original Message ----- >From: "Brooke Clarke" <[EMAIL PROTECTED]> >To: "Tom Van Baak" <[EMAIL PROTECTED]>; "Discussion of precise time and >frequency measurement" <[email protected]> >Sent: Monday, March 06, 2006 10:58 AM >Subject: Re: [time-nuts] FTS4060 Continuing Saga, GPS rain > > > > >>Hi Tom: >> >>I think the problem is related to the FTS4060. During the brown out my >>computer and the SR620 counter reset, but the two green LEDs on the 4060 >>stayed on, at the time my thought was "cool". But the yellow "Align" >>light behind the door has turned on and so far I have not been able to >>get it to turn off. But after trying a bunch of stuff the jitter value >>is now back in the 9 ns area. I have not been able to find anything in >>the manual about operation with the "Align" light on and with the "Lock" >>and "AC Pwr" LEDs on. Does anyone have any ideas about it? >> >>On the rain thing. I think the key parameter of water that matters is >>the dielectric constant which is about 80. The propagation constant is >>proportional to 1 / SQRT( e ) or about 11% of what it is in air. If >>it's 1 ns per foot in air then it's 8.9 ns per foot in water >> >>I haven't figured out how to calculate the total volume of water in the >>column between the satellites and the receiving antenna. I did find a >>web page that shows the terminal velocity of rain and it varies from >>0.02 MPH for small drops to 20 MPH for big drops. But this would need >>to be coupled with the rate of rain fall (inches/hour) to determine how >>much water was in the column. Assuming big drops (20 MPH = 352 IPS) and >>0.1 IPS rain rate says that the rain takes up 1 part in 3520. If the >>height of the rain is 20,000 feet then there's 5.6 feet of rain for a >>delay of 50.5 ns??? >> >>Have Fun, >> >>Brooke >> >>Tom Van Baak wrote: >> >> >> >>>>Rain should have an effect on the timing of the signal, since the >>>>propagation speed of radio waves through water is different from that >>>>through air. It will also attenuate the signal, causing worse S/N >>>>ratio which would cause the lower-elevation satellites to not be seen. >>>> >>>> >>>> >>>> >>>David, >>> >>>Maybe we can figure this out. First, the refractive >>>index of water is about 1.3. So I think this means >>>the propagation speed of radio waves in water is >>>down to about 0.75 c, right? >>> >>>Then, how much water are the GPS signals traveling >>>through? Let's assume the typical amount of rain in >>>a heavy storm is a couple of inches. All that water is >>>either puddles already on the ground, drops on their >>>way down, or moisture still in the clouds waiting to >>>come down. >>> >>>The total amount of water in a cross section column >>>of the atmosphere that the GPS signals travel though >>>is thus a couple of inches total, max. Let's assume >>>a worst case -- 6 inches. >>> >>>So, those GPS signals go through 20,000 km of >>>empty space and atmosphere containing a total of >>>6 inches of water; in which it slows down by 30%. >>>At a ns/foot, this comes to 25 ps per inch of water >>>content in the air; a total of 150 ps in my worst-case >>>example above. >>> >>>My conclusion is that rain or snow, light or heavy, >>>has no effect, even at the ns level. Can someone who >>>really knows double check this back of the envelope >>>calculation? >>> >>>Thanks, >>>/tvb >>> >>> >>> >>>_______________________________________________ >>>time-nuts mailing list >>>[email protected] >>>https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >>> >>> >>> >>> >>> >>> >>-- >>w/Java http://www.PRC68.com >>w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml >>http://www.precisionclock.com >> >>_______________________________________________ >>time-nuts mailing list >>[email protected] >>https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts >> >> > > >_______________________________________________ >time-nuts mailing list >[email protected] >https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > > > > -- w/Java http://www.PRC68.com w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml http://www.precisionclock.com _______________________________________________ time-nuts mailing list [email protected] https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
