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From: Jim Yanik on 24 Oct 2009 18:48
Phil Hobbs <pcdhSpamMeSenseless(a)electrooptical.net> wrote in
news:6qadnTZWGf110H7XnZ2dnUVZ_j6dnZ2d(a)supernews.com:

> a7yvm109gf5d1(a)netzero.com wrote:
>> Hi gang,
>> There seem to be a lot of surplus GPS discliplined 10MHz OCXOs on eBay
>> lately.
>> Anyone here have experience using a setup like that?
>> I'm still looking into getting my lab equipped, I'm looking into the
>> frequency thing.
>> Besides GPS, there's the national standards.
>> The Canadian equivalent to WWV is CHU, they broadcast time signals on
>> a few frequencies.
>> Has anyone tried disciplining an OCXO to the carrier of these signals?
>> The carrier is derived from an atomic clock, but atmospherics probably
>> mean I'd have to average over a few days to get ~10-11 accuracy.
>> I'm not finding a lot of information about CHU setups. I'm guessing a
>> dipole in the backyard, some gain, and that's it?
>
> The usual method is to use WWVB at 60 kHz, with a ferrite loopstick
> antenna, a crystal filter, and a PLL. You can get nice 2400 mu ferrite
> from Amidon. The ground wave delay is more stable than the sky wave
> from the 10 MHz stations.
>
> Cheers
>
> Phil Hobbs
>

I'm surprised there isn't some receiver IC that would do this job,and maybe
a companion IC to do the PLL/dividing.

--
Jim Yanik
jyanik
at
localnet
dot com
From: osr on 24 Oct 2009 19:38
in the late 1980s there was a plan published in radio electronics that
took a radio shack "time cube" receiver and mixed some signals back
with it to lock a reference.

These days its easier to find a used Jupiter GPS or Trimble
Thunderbolt and make a standard. I just bought a ex cell site rubidium
system for 70$ a few months ago. Just add 24V at 4 amps per warmup and
1.7 amps for run.


http://www.google.com/url?q=http://www.jrmiller.demon.co.uk/projects/ministd/frqstd0.htm&ei=qo_jSrSXOoHWlAfh4OCKBw&sa=X&oi=spellmeleon_result&resnum=2&ct=result&ved=0CA8QhgIwAQ&usg=AFQjCNET__pFKRVLxEX3rcML-J7TFTPV6A

The 10 mhz vcxo was 6$ on ebay.

Steve
From: osr on 24 Oct 2009 19:45
Oh and if you cant find a jupiter, (there are none on ebay right now)
let me know,by posting here, I have a few spares.

Steve
From: Jim Thompson on 24 Oct 2009 19:50
On Sat, 24 Oct 2009 17:48:24 -0500, Jim Yanik <jyanik(a)abuse.gov>
wrote:

>Phil Hobbs <pcdhSpamMeSenseless(a)electrooptical.net> wrote in
>news:6qadnTZWGf110H7XnZ2dnUVZ_j6dnZ2d(a)supernews.com:
>
>> a7yvm109gf5d1(a)netzero.com wrote:
>>> Hi gang,
>>> There seem to be a lot of surplus GPS discliplined 10MHz OCXOs on eBay
>>> lately.
>>> Anyone here have experience using a setup like that?
>>> I'm still looking into getting my lab equipped, I'm looking into the
>>> frequency thing.
>>> Besides GPS, there's the national standards.
>>> The Canadian equivalent to WWV is CHU, they broadcast time signals on
>>> a few frequencies.
>>> Has anyone tried disciplining an OCXO to the carrier of these signals?
>>> The carrier is derived from an atomic clock, but atmospherics probably
>>> mean I'd have to average over a few days to get ~10-11 accuracy.
>>> I'm not finding a lot of information about CHU setups. I'm guessing a
>>> dipole in the backyard, some gain, and that's it?
>>
>> The usual method is to use WWVB at 60 kHz, with a ferrite loopstick
>> antenna, a crystal filter, and a PLL. You can get nice 2400 mu ferrite
>> from Amidon. The ground wave delay is more stable than the sky wave
>> from the 10 MHz stations.
>>
>> Cheers
>>
>> Phil Hobbs
>>
>
>I'm surprised there isn't some receiver IC that would do this job,and maybe
>a companion IC to do the PLL/dividing.

There was, then Bowmar went bust...

http://analog-innovations.com/SED/WWVB-Schematic+Data.pdf

...Jim Thompson
--
| James E.Thompson, CTO | mens |
| Analog Innovations, Inc. | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| Phoenix, Arizona 85048 Skype: Contacts Only | |
| Voice:(480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |

With Half My Brain Tied Behind My Back
Still More Clever Than Mr.Prissy Pants
From: who where on 24 Oct 2009 21:19
On Sat, 24 Oct 2009 07:38:45 -0700 (PDT), a7yvm109gf5d1(a)netzero.com
wrote:

>Hi gang,
>There seem to be a lot of surplus GPS discliplined 10MHz OCXOs on eBay
>lately.
>Anyone here have experience using a setup like that?
>I'm still looking into getting my lab equipped, I'm looking into the
>frequency thing.
>Besides GPS, there's the national standards.
>The Canadian equivalent to WWV is CHU, they broadcast time signals on
>a few frequencies.
>Has anyone tried disciplining an OCXO to the carrier of these signals?
>The carrier is derived from an atomic clock, but atmospherics probably
>mean I'd have to average over a few days to get ~10-11 accuracy.
>I'm not finding a lot of information about CHU setups. I'm guessing a
>dipole in the backyard, some gain, and that's it?

Depending on the accuracy you require - and you *did* say hobbyist -
the Jupiter GPSr module is my preferred solution. I'm allergic to the
loooong conditioning times required by many approaches to
GPS-disciplined arrangements. A good example of a Jupiter-based setup
(very similar to my own) can be found at

http://www.jrmiller.demon.co.uk/projects/freqstd/frqstd.htm

The benefits of this type of approach are quick settling from cold
start, and low cost oscillator. Depending on your jitter
requirements, a non-ovened VCXO and a simple loop filter can be more
than satisfactory. I have checked my own 10MHz Jupiter-based
reference against an ovened TC/VCXO counter timebase and cannot
discern any phase jitter on a CRO or with DC recovery on a NBFM
receiver in a comms test set.

<flame suit on for inevitable purist criticism>
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