Re: [time-nuts] Updated VLBI tutorial available on gpstime.com

2007-04-27 Thread Joe Fitzgerald
Tom Clark, K3IO wrote:
> Next week the VLBI community is having another TOW (Technical Operations
> Workshop) at the Haystack Observatory NW of Boston. 

Tom,

I work a few miles down the road from Haystack ... any chance we could 
get together for dinner on Tuesday May 1 to talk timing/AMSAT?

-Joe KM1P


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Re: [time-nuts] Updated VLBI tutorial available on gpstime.com

2007-04-25 Thread Tom Clark, K3IO
Brooke Clarke asked:
> I didn't see in the VLBI slides what was done to "tune" the delay
> line, but did see a hint that there's been a firmware upgrade for it. 
> Can you elaborate?
Rick's latest version uses a delay line with more per-bit precision (now
150 psec steps). We also found that Motorola (correction byte) and
Maxim/DSI (delay line bits) seemed to use different definitions of  "one
nsec" and Rick needed to sort out a scale difference (the reason my new
slides #29 & 30 are different from what's in our PTTI talk).

I think Rick got the cursor clock code from TvB.

73, Tom

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Re: [time-nuts] Updated VLBI tutorial available on gpstime.com

2007-04-25 Thread Brooke Clarke
Hi Tom:

I didn't see in the VLBI slides what was done to "tune" the delay line, but did 
see a hint that there's been a firmware upgrade for it.  Can you elaborate?

I like the Cursor Clock on your web page.

Have Fun,

Brooke Clarke
http://www.PRC68.com
http://www.pacificsites.com/~brooke/PRC68COM.shtml
http://www.precisionclock.com



Tom Clark, K3IO wrote:
> Next week the VLBI community is having another TOW (Technical Operations
> Workshop) at the Haystack Observatory NW of Boston. The audience for the
> TOW is mainly the technicians at each site who drive the telescopes and
> keep the hardware running. VLBI is crucially dependent on timing and
> every station is equipped with at least one Hydrogen Maser. As usual, I
> have been tapped as the timing "teacher".
> 
> My PowerPoint class notes "Timing for VLBI" are now posted available on
> http://gpstime.com/.
> 
> These notes include some fairly recent data on how well the new
> real-time "de-sawtooth" hardware in Rick's CNS Clock II works as
> compared with the software correction we have been using for many years
> (the two agree to 300 psec RMS now that we learned how to "tune" the
> programmable delay line).
> 
> 73, Tom
> 
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> time-nuts mailing list
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[time-nuts] Updated VLBI tutorial available on gpstime.com

2007-04-25 Thread Tom Clark, K3IO
Next week the VLBI community is having another TOW (Technical Operations
Workshop) at the Haystack Observatory NW of Boston. The audience for the
TOW is mainly the technicians at each site who drive the telescopes and
keep the hardware running. VLBI is crucially dependent on timing and
every station is equipped with at least one Hydrogen Maser. As usual, I
have been tapped as the timing "teacher".

My PowerPoint class notes "Timing for VLBI" are now posted available on
http://gpstime.com/.

These notes include some fairly recent data on how well the new
real-time "de-sawtooth" hardware in Rick's CNS Clock II works as
compared with the software correction we have been using for many years
(the two agree to 300 psec RMS now that we learned how to "tune" the
programmable delay line).

73, Tom

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