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Brooke Clarke | 1 Mar 2012 17:41
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Heathkit GC-1000 WWVDO

Hi:

Has anyone done stability plots on the Heathkit GC-1000?  Although it's a clock good to 0.1 seconds, it's
also a WWV 
disciplined oscillator (WWVDO).
The linear power supply makes use of a 7805 and so heats up the enclosure which is hard on the electrolytic
caps but 
also acts as a crystal heater.
On the other hand installing a switching power supply like the PT5101 will cool the enclosure but may
degrade the 
stability of the oscillator.

Are there any WWVB disciplined oscillators (WWVBDO)?

http://www.prc68.com/I/HeathkitGC1000.shtml
http://www.prc68.com/I/Loop.shtml

--

-- 
Have Fun,

Brooke Clarke
http://www.PRC68.com
http://www.end2partygovernment.com/Brooke4Congress.html
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Bob Camp | 1 Mar 2012 18:30
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Re: Heathkit GC-1000 WWVDO

Hi

Spectracom used to be in the WWVB / OCXO combo business. They had a few that
likely fit the modern definition of disciplined. I don't think anybody ever
did a WWV disciplined unit. The path delay issues are just to crazy.

Back when they were new, NBS / NIST was not very happy about the accuracy
that Heathkit advertised for the WWV receivers. I don't think the design had
a problem as much as the marketing sheets.

Bob

-----Original Message-----
From: time-nuts-bounces@...
[mailto:time-nuts-bounces@...] On
Behalf Of Brooke Clarke
Sent: Thursday, March 01, 2012 11:41 AM
To: time-nuts@...
Subject: [time-nuts] Heathkit GC-1000 WWVDO

Hi:

Has anyone done stability plots on the Heathkit GC-1000?  Although it's a
clock good to 0.1 seconds, it's also a WWV 
disciplined oscillator (WWVDO).
The linear power supply makes use of a 7805 and so heats up the enclosure
which is hard on the electrolytic caps but 
also acts as a crystal heater.
On the other hand installing a switching power supply like the PT5101 will
cool the enclosure but may degrade the
(Continue reading)

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Chris Albertson | 1 Mar 2012 18:36
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Re: Heathkit GC-1000 WWVDO

Does an NTP server using WWV as a reference clock count as a WWVDO?
If so then there are likely a few of them around.

I have a really nice RF front from an old WWV receiver that I want to
get working.  Well it does work but I'm using a general coverage
reciever to convert the IF to audio, need to replace that.   I also
have a  c-max wwvb receiver.  The goal is to run them as NTP reference
clocks.   I know they are not as good as GPS but the point to to
measure the delay and hopefully learn something about ionosphere from
the delay.

But both of these are looking at the data streams.  Maybe better to
look at the carrier and lock an XO to that?

On Thu, Mar 1, 2012 at 8:41 AM, Brooke Clarke <brooke@...> wrote:
> Hi:
>
> Has anyone done stability plots on the Heathkit GC-1000?  Although it's a
> clock good to 0.1 seconds, it's also a WWV disciplined oscillator (WWVDO).
> The linear power supply makes use of a 7805 and so heats up the enclosure
> which is hard on the electrolytic caps but also acts as a crystal heater.
> On the other hand installing a switching power supply like the PT5101 will
> cool the enclosure but may degrade the stability of the oscillator.
>
> Are there any WWVB disciplined oscillators (WWVBDO)?
>
> http://www.prc68.com/I/HeathkitGC1000.shtml
> http://www.prc68.com/I/Loop.shtml
>
> --
(Continue reading)

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Bob Camp | 1 Mar 2012 19:05
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Re: Heathkit GC-1000 WWVDO

Hi

I would guess that to count as disciplined, the OCXO (or Rb) needs to be
phase or frequency locked to the incoming signal. NTP normally just does an
estimate of where things should be and moves on.

With either WWVB or WWV, the phase change in the carrier is pretty massive.
To use carrier phase you would  need a multi day average to feed the loop. 

Bob

-----Original Message-----
From: time-nuts-bounces@...
[mailto:time-nuts-bounces@...] On
Behalf Of Chris Albertson
Sent: Thursday, March 01, 2012 12:37 PM
To: Discussion of precise time and frequency measurement
Subject: Re: [time-nuts] Heathkit GC-1000 WWVDO

Does an NTP server using WWV as a reference clock count as a WWVDO?
If so then there are likely a few of them around.

I have a really nice RF front from an old WWV receiver that I want to
get working.  Well it does work but I'm using a general coverage
reciever to convert the IF to audio, need to replace that.   I also
have a  c-max wwvb receiver.  The goal is to run them as NTP reference
clocks.   I know they are not as good as GPS but the point to to
measure the delay and hopefully learn something about ionosphere from
the delay.
(Continue reading)

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Chuck Forsberg WA7KGX N2469R | 1 Mar 2012 20:36
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Re: Heathkit GC-1000 WWVDO

In the late 70s I added WWVB to the micro that controlled
my RTTY autostart station.  A circuit in an application manual
demodulated the WWVB signal and a software loop synced
to the on-the-second transitions and decoded the time information.

--

-- 
Chuck Forsberg WA7KGX N2469R     caf@...   www.omen.com
Developer of Industrial ZMODEM(Tm) for Embedded Applications
   Omen Technology Inc      "The High Reliability Software"
10255 NW Old Cornelius Pass Portland OR 97231   503-614-0430
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John Ackermann N8UR | 1 Mar 2012 20:53
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Re: Heathkit GC-1000 WWVDO


On Mar 1, 2012, at 11:41 AM, Brooke Clarke <brooke@...> wrote:

>Are there any WWVB disciplined oscillators (WWVBDO)?

I have a couple of Spectracom 8164 WWVB DOs running.  They bounce around by a part or three in 10e10.

The 8164 uses an FLL that does 1000 second counts of the internal OCXO reference vs. a 10 MHz crystal that is
tightly locked to the WWVB carrier.  An algorithm adjusts a DAC based on the counter results, after
applying sanity checks (e.g., I think it requires two or three consecutive counts within some tolerance
before it makes an adjustment).

John
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