measurement time-nuts@febo.com
Sent: Wednesday, September 18, 2013 7:25 PM
Subject: Re: [time-nuts] GPSDO vs Rb standard
Hi
When I want to tune an Rb, I just hook up to it with a terminal program and
hack away at it. There's not a lot to the protocol.
Bob
: [time-nuts] GPSDO vs Rb standard
Hi
When I want to tune an Rb, I just hook up to it with a terminal program and
hack away at it. There's not a lot to the protocol.
Bob
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To: Discussion of precise time and frequency measurement time-nuts@febo.com
Sent: Friday, September 20, 2013 5:34 PM
Subject: Re: [time-nuts] GPSDO vs Rb standard
Hi
All of my FE Rb's have serial out of a 9 pin D connector. They bring power
(+15 and +5) in on that connector
I hooked the Rb's 1PPS to the trigger input on my old Tek 455, 10MHz
GPSDO to Channel A, .05us trace, and turned the lights out so I could
see it. The 10MHz is marching right to left about 1 cycle every 20
seconds. So, can I say that the Rb considers my GPSDO to be too fast by about
5ppb?
Hi
One cycle of 10 MHz would be 100 ns. 100 ns per second would be 100 ppb. 100ns
per 20 seconds would indeed be 5 ppb.
Since the Rb is *stable* but not *accurate*, the real question is - how much
does the 5 ppb change by? The Rb can't tell you if the GPSDO is correct. The
best it can do is
and frequency measurement time-nuts@febo.com
Sent: Wednesday, September 18, 2013 5:01 PM
Subject: Re: [time-nuts] GPSDO vs Rb standard
Hi
One cycle of 10 MHz would be 100 ns. 100 ns per second would be 100 ppb. 100ns
per 20 seconds would indeed be 5 ppb.
Since the Rb is *stable
Instead of using the Rb's PPS, use the GPS receiver's PPS. Maybe you
will find out that the Rb is slow... you can also check the Rb's PPS
against the GPS's PPS.
On Wed, Sep 18, 2013 at 11:47 PM, Bob Stewart b...@evoria.net wrote:
I hooked the Rb's 1PPS to the trigger input on my old Tek 455,
Azelio and Fellow Time Nuts,
Isn't the GPS 1PPS signal supposed to be 'precise' to within what error? I
imagine this is in the specs of the specific receiver -
but I was wondering if some of you have actually measured what that is -
and could report the numbers that you have found.
Thanks!
John
is time consuming to say the least.
Bob
From: John C. Westmoreland, P.E. j...@westmorelandengineering.com
To: Discussion of precise time and frequency measurement time-nuts@febo.com
Sent: Wednesday, September 18, 2013 6:13 PM
Subject: Re: [time-nuts] GPSDO vs Rb
, P.E. j...@westmorelandengineering.com
To: Discussion of precise time and frequency measurement time-nuts@febo.com
Sent: Wednesday, September 18, 2013 6:13 PM
Subject: Re: [time-nuts] GPSDO vs Rb standard
Azelio and Fellow Time Nuts,
Isn't the GPS 1PPS signal supposed to be 'precise' to within
Hi
The Rb's have a couple of issues:
1) Its been years since they were set on frequency and they do have a yearly
drift rate
2) They have a temperature coefficient of drift that may be fairly large (0.1
ppb over -30 to +70)
3) They self heat quite a bit, so they do move temperature / need a
...@westmorelandengineering.com
To: Discussion of precise time and frequency measurement
time-nuts@febo.com
Sent: Wednesday, September 18, 2013 6:13 PM
Subject: Re: [time-nuts] GPSDO vs Rb standard
Azelio and Fellow Time Nuts,
Isn't the GPS 1PPS signal supposed to be 'precise' to within what error? I
, 2013 5:01 PM
Subject: Re: [time-nuts] GPSDO vs Rb standard
Hi
One cycle of 10 MHz would be 100 ns. 100 ns per second would be 100 ppb.
100ns per 20 seconds would indeed be 5 ppb.
Since the Rb is *stable* but not *accurate*, the real question is - how much
does the 5 ppb change
time and frequency measurement time-nuts@febo.com
Sent: Wednesday, September 18, 2013 7:22 PM
Subject: Re: [time-nuts] GPSDO vs Rb standard
Hi
The Rb's have a couple of issues:
1) Its been years since they were set on frequency and they do have a yearly
drift rate
2) They have a temperature
to the heat
sink. Good idea? Anybody got a busted one?
Bob
From: Bob Camp li...@rtty.us
To: Discussion of precise time and frequency measurement
time-nuts@febo.com
Sent: Wednesday, September 18, 2013 7:22 PM
Subject: Re: [time-nuts] GPSDO vs Rb
of precise time and frequency measurement
time-nuts@febo.com
Sent: Wednesday, September 18, 2013 7:22 PM
Subject: Re: [time-nuts] GPSDO vs Rb standard
Hi
The Rb's have a couple of issues:
1) Its been years since they were set on frequency and they do have a yearly
drift rate
2
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