At 04:48 PM 5/8/2010, Larry Gerhardstein wrote:

My PC's clock keeps getting off by enough to cause problems on near overhead passes. I've seen it off by more than 30 seconds. It is using Internet synchronization, which happens once a week....

Hi Larry,

I use EZTimeSync. It is free and you can set how often you want it to update.

Available here:

http://www.tucows.com/preview/219295

73, Tony AA2TX

I use one of the following located at my site.:

ftp://bristor-assoc.com/pub/Amateur/atmtm22.exe

ftp://bristor-assoc.com/pub/Amateur/atomic-clock.exe

The first one allows multiple syncs during the day. The second once a day. You can Google the names and probably get newer versions, but have found these to work well and have them on all of my systems.

Regards,

Reid, W4 UPD AMSAT: #17002

Larry Gerhardstein wrote:

My PC's clock keeps getting off by enough to cause problems on near overhead passes. I've seen it off by more than 30 seconds. It is using Internet synchronization, which happens once a week. Is there a way to force Windows 7 to automatically update clock more frequently than once per week. Please don't tell me to monkey with the Windows Registry. I know PC clocks are notoriously inaccurate, but this is ridiculous.

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Hi Larry,

run regedit and change the update interval

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\W32Time\Config

change UpdateInterval to 3600 (decimal) -> every hour

73, Mike DK3WN

-----Ursprüngliche Nachricht----- Von: amsat-bb-bounces@amsat.org [mailto:amsat-bb-bounces@amsat.org] Im Auftrag von Al Zoller Gesendet: Sonntag, 9. Mai 2010 00:08 An: W7IN@montana.com; AMSAT-BB Betreff: [amsat-bb] Re: PC clock

Hi Larry,

Time synchronization is scheduled in the 'Task Manager' of Win 7. Open 'Task Manager' and look for the item and edit it. Thanks for bringing this to my attention as I just upgraded (?) to Win 7. I set mine to sync at startup as I turn the PC off at night. My tracking software (Nova) also does it when it is started. Also updates Keps.

73 de N7UB, Al

On 5/8/2010 2:48 PM, Larry Gerhardstein wrote:

My PC's clock keeps getting off by enough to cause problems on near overhead passes. I've seen it off by more than 30 seconds. It is using Internet synchronization, which happens once a week. Is there a way to force Windows 7 to automatically update clock more frequently than once per week. Please don't tell me to monkey with the Windows Registry. I know PC clocks are notoriously inaccurate, but this is ridiculous.

Larry W7IN _______________________________________________ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb

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Hi Larry,

I know PC clocks are not all that accurate, but we're talking seconds per month. Needing to update a clock more often than that probably isn't due to the PC hardware. I've never had one be off this much unless the clock battery was dead, and any PC new enough to run Win-7 isn't going to have that issue. I would suspect that there is a some software you are running that is messing it up. Back in the DOS days, this was a common occurrence, and I'm surprised to hear about it under something more modern, but my gut feel tells me that is what is happening.

Maybe a device driver or something else low-level. Try booting something else (a "Live" CD of Linux, for example) to prove the hardware is good. Go back to Windows piece by piece. If you can figure out which it is, then this whole idea of applying bandaids can go away.

Just a thought,

Greg KO6TH

From: ve4yz@hotmail.com To: mail@mike-rupprecht.de; n7ub@littleappletech.com; W7IN@montana.com; amsat-bb@amsat.org Date: Sun, 9 May 2010 06:59:52 -0500 Subject: [amsat-bb] Re: PC clock

Even though Larry doesn't want to play with the registry it is IMHO the fastest and easiest, and, you don't have someone else' utility doing exactly that automagically for you.

In WIN7 I've done...

HKLM\System\CurrentControlSet\Services\W32time\TimeProviders\NTPClient and changed SPECIALPOLLINTERVAL to a decimal 3600 or whatever you want.

-----Original Message----- From: amsat-bb-bounces@amsat.org [mailto:amsat-bb-bounces@amsat.org] On Behalf Of Mike Rupprecht Sent: Sunday, May 09, 2010 5:33 AM To: 'Al Zoller'; W7IN@montana.com; 'AMSAT-BB' Subject: [amsat-bb] Re: PC clock

Hi Larry,

run regedit and change the update interval

HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\services\W32Time\Config

change UpdateInterval to 3600 (decimal) -> every hour

73, Mike DK3WN

-----Ursprüngliche Nachricht----- Von: amsat-bb-bounces@amsat.org [mailto:amsat-bb-bounces@amsat.org] Im Auftrag von Al Zoller Gesendet: Sonntag, 9. Mai 2010 00:08 An: W7IN@montana.com; AMSAT-BB Betreff: [amsat-bb] Re: PC clock

Hi Larry,

Time synchronization is scheduled in the 'Task Manager' of Win 7. Open 'Task Manager' and look for the item and edit it. Thanks for bringing this to my attention as I just upgraded (?) to Win 7. I set mine to sync at startup as I turn the PC off at night. My tracking software (Nova) also does it when it is started. Also updates Keps.

73 de N7UB, Al

On 5/8/2010 2:48 PM, Larry Gerhardstein wrote:

...

My PC's clock keeps getting off by enough to cause problems on near overhead passes. I've seen it off by more than 30 seconds. It is using Internet synchronization, which happens once a week. Is there a way to force Windows 7 to automatically update clock more frequently than once per week. Please don't tell me to monkey with the Windows Registry. I know PC clocks are notoriously inaccurate, but this is

ridiculous.

...

Larry W7IN _______________________________________________ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb

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Hi Larry,

Ok, I understand the need for an accurate clock, though I believe you're expectations for being able to track an overhead pass is pushing the limits of orbital prediction pretty hard. Another ham I know locally tried this, and ultimately gave up. His issue was not one of clock accuracy, but of Keps and the mathematics behind them.

But, you've still got a PC that isn't working right, and that bugs me. I just checked my PC, and it was spot on with WWV (clock changed at the chime). So, a question... Did the clock drift before the serial port was installed? Perhaps what you need is a new driver or a different type of serial port, if you haven't exhausted that route already.

Greg KO6TH

Date: Sun, 9 May 2010 21:23:58 -0600 From: W7IN@montana.com To: ko6th_greg@hotmail.com CC: amsat-bb@amsat.org Subject: Re: [amsat-bb] Re: PC clock

Greg,

During the process of getting a serial port interface that worked properly with W7-64b, I experienced a myriad of system crashes. This is possibly why my clock got off by about +30 seconds. I often check my PC's clock against the WWV clock on my wall, especially when tracking birds. It's now on to within a second. If it got off by more than 2 or 3, I'd want to corrected it; the problem is not Doppler, it's a near overhead pass (that's when I discovered the PC time error). Plus, I want correction automatic and not have to mess with it for a long time. I believe the once-a-week default in Win7 for syncing PC time with Internet server time is too loose. Once a day or even once an hour seems better to me.

73, Larry W7IN

On 5/9/2010 7:05 PM, Greg D. wrote:

Hi Larry,

I know PC clocks are not all that accurate, but we're talking seconds per month. Needing to update a clock more often than that probably isn't due to the PC hardware. I've never had one be off this much unless the clock battery was dead, and any PC new enough to run Win-7 isn't going to have that issue. I would suspect that there is a some software you are running that is messing it up. Back in the DOS days, this was a common occurrence, and I'm surprised to hear about it under something more modern, but my gut feel tells me that is what is happening.

Maybe a device driver or something else low-level. Try booting something else (a "Live" CD of Linux, for example) to prove the hardware is good. Go back to Windows piece by piece. If you can figure out which it is, then this whole idea of applying bandaids can go away.

Just a thought,

Greg KO6TH

<snip>

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----- Original Message ----- From: "Greg D." ko6th_greg@hotmail.com To: w7in@montana.com Cc: amsat-bb@amsat.org Sent: Tuesday, May 11, 2010 7:47 AM Subject: [amsat-bb] Re: PC clock

Hi Larry,

Ok, I understand the need for an accurate clock, though I believe you're expectations for being able to track an overhead pass is pushing the limits of orbital prediction pretty hard. Another ham I know locally tried this, and ultimately gave up. His issue was not one of clock accuracy, but of Keps and the mathematics behind them.

Greg KO6TH

Hi Greg, KO6TH

When the software calculate the Az and the El of the satellite at the right time with an accurate clock then it send a command to the rotators but the antennas takes a certain time to go in that calculated position and when the antennas are finally there then the satellite is already in another position far advanced in it's orbital path particularly when the satellite pass is overhead.

I dont think you want to run the motors every 5 or 10 seconds othervise your control relays will work as a machine-gun

So the issue is not on clock accuracy or Keps or mathematics behind them but it is on the tracking system that we normally use to mimichaise the satellite position with a phase difference between the satellite calculated position and the actual antenna position when the traching command is sent to the motors.

If you go over the roof and you follow the ISS by naked eye you will realize that your antenna pointing is always a little bit behind the ISS position in the sky and so a very accurate clock to track a LEO satellite is meaning less particularly using high gain antennas with a narrow main lobe.

73" de

i8CVS Domenico

Hello Mark, Domenico and others, when SatPC32 updates the antenna positions it turns the antennas a half step in front of the satellites position. The manual says:

"Under all tracking options, the rotors are activated with a precession of one half step, either one half of the time interval or one half of the tracking angle, to ensure that the satellite moves through the antenna focus."

73s, Erich, DK1TB

----- Original Message ----- From: "Mark L. Hammond" marklhammond@gmail.com To: "i8cvs" domenico.i8cvs@tin.it Cc: "AMSAT-BB" amsat-bb@amsat.org; W7IN@montana.com Sent: Tuesday, May 11, 2010 10:25 PM Subject: [amsat-bb] Re: PC clock

Hello Domenico,

The very excellent SatPC32 program "leads" so as to keep an accurate pointing at a satellite. It has several adjustments for how often the rotors are updated, gain consideration of the antennas in use, etc.

73,

Mark N8MH

On Tue, May 11, 2010 at 4:07 PM, i8cvs domenico.i8cvs@tin.it wrote:

----- Original Message ----- From: "Greg D." ko6th_greg@hotmail.com To: w7in@montana.com Cc: amsat-bb@amsat.org Sent: Tuesday, May 11, 2010 7:47 AM Subject: [amsat-bb] Re: PC clock

...

Hi Larry,

Ok, I understand the need for an accurate clock, though I believe you're expectations for being able to track an overhead pass is pushing the limits of orbital prediction pretty hard. Another ham I know locally tried this, and ultimately gave up. His issue was not one of clock accuracy, but of Keps and the mathematics behind them.

Greg KO6TH

Hi Greg, KO6TH

When the software calculate the Az and the El of the satellite at the right time with an accurate clock then it send a command to the rotators but the antennas takes a certain time to go in that calculated position and when the antennas are finally there then the satellite is already in another position far advanced in it's orbital path particularly when the satellite pass is overhead.

I dont think you want to run the motors every 5 or 10 seconds othervise your control relays will work as a machine-gun

So the issue is not on clock accuracy or Keps or mathematics behind them but it is on the tracking system that we normally use to mimichaise the satellite position with a phase difference between the satellite calculated position and the actual antenna position when the traching command is sent to the motors.

If you go over the roof and you follow the ISS by naked eye you will realize that your antenna pointing is always a little bit behind the ISS position in the sky and so a very accurate clock to track a LEO satellite is meaning less particularly using high gain antennas with a narrow main lobe.

73" de

i8CVS Domenico

---

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At 12:07 PM 5/11/2010, i8cvs wrote:

----- Original Message ----- From: "Greg D." ko6th_greg@hotmail.com To: w7in@montana.com Cc: amsat-bb@amsat.org Sent: Tuesday, May 11, 2010 7:47 AM Subject: [amsat-bb] Re: PC clock

...

Hi Larry,

Ok, I understand the need for an accurate clock, though I believe you're expectations for being able to track an overhead pass is pushing the limits of orbital prediction pretty hard. Another ham I know locally tried this, and ultimately gave up. His issue was not one of clock accuracy, but of Keps and the mathematics behind them.

Greg KO6TH

Hi Greg, KO6TH

When the software calculate the Az and the El of the satellite at the right time with an accurate clock then it send a command to the rotators but the antennas takes a certain time to go in that calculated position and when the antennas are finally there then the satellite is already in another position far advanced in it's orbital path particularly when the satellite pass is overhead.

I dont think you want to run the motors every 5 or 10 seconds othervise your control relays will work as a machine-gun

So the issue is not on clock accuracy or Keps or mathematics behind them but it is on the tracking system that we normally use to mimichaise the satellite position with a phase difference between the satellite calculated position and the actual antenna position when the traching command is sent to the motors.

If you go over the roof and you follow the ISS by naked eye you will realize that your antenna pointing is always a little bit behind the ISS position in the sky and so a very accurate clock to track a LEO satellite is meaning less particularly using high gain antennas with a narrow main lobe.

73" de

i8CVS Domenico

---

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Good point! I guess if we had software that could provide a position slightly in advance of the satellite so the tracking could be a series of short drifts thru the beam of the antennas...that would be ideal. Also much more complicated since the lead time/angle would vary by satellite pass, and ground station antenna parameters. Tracking Leo satellites on s-band with a two-foot dish can be demanding considering the narrow beamwidth. Fortunately, one does not need that much gain for Leos.

When I track the Moon, manually, this is what I do. But the Moon apparent motion in the sky is about 15-degrees/hour in azimuth so with 16-degree 2m antennas it only requires repointing 2-3 times per hour. At 1296 my eme antenna beamwidth is 3-degrees so keeping peaked within 1-dB requires much more frequent movement (10 or more times/hour). Fortunately, most auto-track sw has input for how often to command the rotators.

My 16-foot dish actuators rotate the dish fairly slow (90-deg/5-min), so it takes some time for repointing. I can resolve 0.1 degree movement.

73, Ed - KL7UW, WD2XSH/45 ====================================== BP40IQ 500 KHz - 10-GHz www.kl7uw.com EME: 144-600w, 432-100w, 1296-60w, 3400-fall 2010 DUBUS Magazine USA Rep dubususa@hotmail.com ======================================

I'm using Dimension 4 http://www.thinkman.com/dimension4/index.htm

You can set the program to whatever pc clock updating interval you want. I set mine to each 5 minutes and my clock is always at a fraction of second in error.

Orbitron is also setting your PC clock at each startup. But it now always working giving the exceending time error often at the first launch you hace to retry manually in the program.

"-"

Luc Leblanc VE2DWE Skype VE2DWE www.qsl.net/ve2dwe DSTAR urcall VE2DWE WAC BASIC CW PHONE SATELLITE

Thanks all for the many many replies, (almost too many to count) both here and off-list, to my post about PC time being in error. After considering many, I have taken the advice of Mike DK3WN and Alan VE4YZ and performed the registry edit they both recommended. I have my PC now updating time once every hour, a 3600 second delta. So far, my PC time is no more than one second off compared to WWV time. I do not like messing with the windows registry, but in this case, it was sound advice. Tnx and 73,

Larry W7IN in DN27, Plains Montana

On 5/8/2010 5:13 PM, Larry Gerhardstein wrote:

Some of the internet time syncing tools recommended are not compliant with Win 7 64-bit O/S. I will not be chasing those further and hope to edit the time sync service that already exists in Win 7.

Larry W7IN

On 5/8/2010 2:48 PM, Larry Gerhardstein wrote:

...

My PC's clock keeps getting off by enough to cause problems on near overhead passes. I've seen it off by more than 30 seconds. It is using Internet synchronization, which happens once a week. Is there a way to force Windows 7 to automatically update clock more frequently than once per week. Please don't tell me to monkey with the Windows Registry. I know PC clocks are notoriously inaccurate, but this is ridiculous.

Larry W7IN _______________________________________________ Sent via AMSAT-BB@amsat.org. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb

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