[time-nuts] Tbolt temperature sensor
I don't know if it is bad... but it certainly can't be good... BTW, my newer Tbolt is a second group TAPR unit I am pretty sure it shows the same firmware (3.0) / build (10.2) versions as an earlier one that does not show the "problem". I am thinking it may be caused by changes in the sensor chip (or it could be a bad batch... mine was made within days of Asa's unit which also shows the flat temperature line). The firmware is definitely doing the "subtract 0.25C" step of the high resolution read cycle. It is just not producing the extra digits from the counter/slope registers. - I wonder how that affects holdover compensation. It seems that my TAPR Tbolt has moves the DAC by about 1e-4 V, or 5e-4Hz, per 0.1C. 0.5C represents a huge step of something like 2.5e-10. --bruce w1bw _ Hotmail® goes where you go. On a PC, on the Web, on your phone. http://www.windowslive-hotmail.com/learnmore/versatility.aspx#mobile?ocid=TXT_TAGHM_WL_HM_versatility_121208 ___ 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] Austron 1250A Manual
Hi gang, I just put a scan of the Austron 1250A manual on the www.to-way.com site. 1.3 MB .pdf 300x300 monochrome. Had ___ 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] Tbolt temperature sensor
On Fri, Jan 30, 2009 at 8:37 AM, Mark Sims wrote: > The newer units can show lots of high frequency oscillations in the > temperature reading as the DS1620 readings jitter around the 0.5 degree > temperature steps. I wonder how that affects holdover compensation. It seems that my TAPR Tbolt has moves the DAC by about 1e-4 V, or 5e-4Hz, per 0.1C. 0.5C represents a huge step of something like 2.5e-10. --bruce w1bw ___ 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] Canada's 5,000 year old calendar
On 1/29/09 5:13 PM, "Magnus Danielson" wrote: > M. Warner Losh skrev: >> In message: <25630a120901291622l5cc165ecna06e01cc3de52...@mail.gmail.com> >> michael taylor writes: >> : An academic maverick is challenging conventional wisdom on Canada's >> : prehistory by claiming an archeological site in southern Alberta is >> : really a vast, open-air sun temple with a precise 5,000-year-old >> : calendar predating England's Stonehenge and Egypt's pyramids. >> ... >> : Since we had some discussion about historic calendars earlier this >> : year, I thought it might of interest here. >> >> I wonder if he has accounted for the progression in the earth's wobble >> over the past 5k years to make his claims... > > Hmm... never check a story too closely... :) > > I think to recall that that kind of people use software that can fairly > accurately re-play sky-events back in time... considering various of > long-term drift effects. Would love to fool around with that kind of > stuff... but it is probably unobtainables for mere mortals like me. I haven't read the article yet (I'm going to though) I wouldn't count on them having a fancy sky simulator. For all you know, they've got something that just has a "good enough" approximation to do right now, and they plugged in a date for 5000 years ago. There's applications that do this sort of thing for Palm Pilots and iPhones for instance. I have a little Celestron SkyScout (a very nifty device) and it has a GPS receiver and magnetic sensor, so you can punch in what planet you want to look at, and it figures out where to point, presumably by using some sort of programmed ephemeris. However, the accuracy of that ephemeris probably significantly degrades if you were to somehow enter a date (normally picked up from GPS) 200 years ago or in the future. Ditto for the "go to" telescopes. There ARE very accurate planetary ephemerides available for free. Check out CCMATLAB (not free, but cheap) for an interface to the JPL Ephemerides algorithms. These are basically numerically integrated differential equations used for predicting the motions of heavenly bodies for doing, among other things, spacecraft navigation. http://ssd.jpl.nasa.gov/horizons.cgi http://ssd.jpl.nasa.gov/?ephemerides You can download them all from various JPL sites. Jim ___ 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] Tbolt temperature sensor
My latest Thunderbolt is one from March 2005 (like Asa's). The others are much earlier production. The later production units seem to handle the temperature sensor differently. Tbolts use a DS1620 sensor chip. This chip reports the temperature in 0.5C increments, but has support for getting higher resolution. The earlier production tbolts generated a smooth temperature curve that tracked temperature changes gracefully.On the later production tbolts you usually see a flat temperature plot with the temperature quantized to 0.25C/0.75C values. This indicates that the Tbolt firmware is doing at least part of the high resolution temperature read cycle shown in the DS1620 data sheet. The first part of this is to take the temperature reading (0.5C steps), knock off the lower bit, and subtract 0.25C. You should then read some counter registers and do some arithmetic to generate the high res temp reading. It appears that the later production units are not doing this (or later DS1620 chips do not support the counter registers) because the temperature plot is always quantized to 0.25C/0.75C (except for some apparent software filtering that is performed when the value changes). One side effect of the coarse temperature steps in the later Tbolts is that cause Lady Heather to log lots of temperature spikes. The eralier tbolts produced nice smooth curves with an occasional temperature spike (that I now suspect is due to boundary conditions in the DS1620 count registers) that quickly faded away. The newer units can show lots of high frequency oscillations in the temperature reading as the DS1620 readings jitter around the 0.5 degree temperature steps. _ Windows Live™ Hotmail®:…more than just e-mail. http://windowslive.com/explore?ocid=TXT_TAGLM_WL_t2_hm_justgotbetter_explore_012009 ___ 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] Astro-paleology or paleo-astronomy
Hi Magnus, I am sure I have at least one astro planetarium program somewhere (it doesnt get much use here) that will allow you to set the clock to 5000BC not GPS disciplined though :-)) I will have to check the detail. One was written by a good friend now deceased. Alan G3NYK ___ 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] Lady Heather Update
Hi Mark, Again thanks. Kind regards, Gerald VK3FGJM -Original Message- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Mark Sims Sent: Friday, 30 January 2009 3:28 PM To: time-nuts@febo.com Subject: [time-nuts] Lady Heather Update Here is an updated version of the good Lady Heather's GPS Disciplined Oscillator control program for the Thunderbolt. This version adds command line support for setting the video mode: /VS = 800x600 /VM = 1024x768 (default) /VL = 1280x960 (also good for 1280x1024) /? for command line help Again, the compiled version is for DOS/WIN98 and mayby WIN ME, WIN/NT DOS mode on systems with a VESA compatible video BIOS. _ Windows Live(tm) Hotmail(r)...more than just e-mail. http://windowslive.com/howitworks?ocid=TXT_TAGLM_WL_t2_hm_justgotbetter_ howitworks_012009 -- Message protected by MailGuard: e-mail anti-virus, anti-spam and content filtering. http://www.mailguard.com.au/mg ___ 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.
