10 MHz Reference Standard

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SyncTronX

SyncTronX

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Joined 2008
#1
What are thoughts about having a 10MHz Reference Standard for use
on the bench and with connections for the various meters that can use
a 10MHz standard input?

I found some YouTube DIY projects that seem to be pretty good but I'm
not sure how they compare with available standards that we could by
on the surplus or other market.

I'll post a link here to one project that used the Arduino that seemed
pretty top notch. But no circuit boards etc.

Here is the link: GPS Locked Frequency Reference Standard

There is four videos in this series.
 
#2
Almost anyone working in electronics will find a frequency reference useful at some point for something. I've had several of them at my bench for many years. Although I don't use them much anymore, the timebase in my microwave counter has a high stability TCXO that is always on as long as the counter has AC power. The output cable is on the left handle. Then there is a stand alone 5 meg source with 1 meg and 100K Hz divided outputs. It's an AN/URQ-23 from the military with battery backup. The crystal is enclosed in a Dewer flask. I was told it was part of the early patriot missile system. I also have a small 10MHz rubidium oscillator somewhere that I never did hook up. Maybe I should get to that someday. All it needs is a small 24v DC source and a cabinet.

Numerous rubidium sources can be found on eBay. murphyjunk in California has a nice one pretty cheap. He sells it with the Winchester connector that's hard to find alone. This oscillator will need to be mounted on a heat sink because they were used in aircraft and so have an extra heater, but not a big problem.
 

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#3
Years ago you could buy surplus Hewlett Packard Z3801A GPS based frequency standard used to synchronize CDMA cellular land network wireless base stations.
I picked up a couple of them at a hamfest. They required some jumpers on the main board and 48vdc power. There is free software (Satsat) for control and monitoring. They output a nice 10mhz signal. I use one on my DMR repeater and the other for Oscope and spectrum analyzer.
There are some Chinese versions out there and you can still find the HP and Trimble units.
 
#5
Okay, that is all good stuff. I hear ya Hollow State, and yes,
it's not like its going to be an everyday need.

At some point for something--that is what I was thinking too.

But I figure might as well have something reliable that doesn't break
the bank and when I need time or frequency data it will be accurate
and can sync up my instruments to the clock.

I passed up a few that I saw local on ebay that I think would have
been okay, they were NOS stuff, I assume left over from the telecom bust.
I'm sure there are some more about, but where is a guess?

I'm sure there are china versions...not really sure I want to go down
that road...as I don't know which are the good ones....

This is after all my first foray into the time zone.

Cheers,
 
#7
Is there much of a difference between the accuracy of the GPS vs. Ovenized
crystals?

So for the murphyjunk we are talking a $200 ruhibium standard and power supply.
This comes with the interface between the two but no other information I believe.

So just hook it up and away to go? That's it? I assume they are pretty
accurate too.

Well I found this and answered my question:

Link

Then it looks like the most bang for the buck is the GPS Synchronous
which comes in a 1 * 10^-11. wondering if there are hidden costs.


Cheers,
 
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#10
SyncTronX said:
Is there much of a difference between the accuracy of the GPS vs. Ovenized
crystals?
Click to expand...
Yes, a huge difference. GPS has excellent long-term accuracy and awful short-term accuracy. A crystal has excellent short-term accuracy and moderately good long-term accuracy. That is why a GPS-based frequency source phase-locks a crystal to GPS, so you get the short-term accuracy of a crystal with the long-term accuracy of GPS.

Nothing whatsoever to do with audio, though. Audio requires reasonable short-term accuracy (almost any crystal will do) and is quite happy with mediocre long-term accuracy.
 
#11
The best value for a while was a Thunderbolt. They were around $150 from eBay with antenna and supply. The oscillators were very good and GPS locked hard to beat. Overkill for audio but its nice to know your 10 MHz reference for the counter is in PPT. It is useful for checking digital audio clocks with a good counter. A good 10 MHz ovenized oscillator may not be in PPT but close enough for most tasks. This + a simple supply is probably more than good enough: CTS 1960017 OCXO 10Mhz Oven Controlled Crystal Oscillators for $20. Get a good counter to go with it like this: Hewlett Packard HP 5316A Universal Counter HP-IB used | eBay which you could pick up local.
 
#13
That is really first rate kit Harry. The HP Z3801A at the time I bought mine they were cheap enough to buy several, $50 range. The one from the British ham is nicer in the fact it will run on a typical 12vdc system that so much of our ham gear uses plus being much smaller. The HP is happy with 49-52vdc.
 
#14
Thanks, I'm still looking. Every little bit helps.
Dave, points well taken.
Demian, definitely a budget king there...and the HP Counter is worth looking into.
Harry, I kind like that Simple GPS Stabilized 10 MHZ Oscillator, there,
and for about the same price of the Murphyjunk one...that Simple Stab, GPS
unit with 12 volts....heck, even a wall wort would do...Then a GPS antenna
as with the others I think.

I think the RF stuff is interesting, plus I came across a stash of those
gold Helicopter looking Bipolars and FETs...along with some of those
funky single mica flat RF caps.

Cheers,
 
#16
drpro said:
That is really first rate kit Harry. The HP Z3801A at the time I bought mine they were cheap enough to buy several, $50 range. The one from the British ham is nicer in the fact it will run on a typical 12vdc system that so much of our ham gear uses plus being much smaller. The HP is happy with 49-52vdc.
Click to expand...

Down East Microwave sells a nice 4 way divider and they can be chained if you need more outputs.

Look Here: Assembled or Kit




.
 
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#17
SyncTronX said:
Thanks, I'm still looking. Every little bit helps.
Dave, points well taken.
Demian, definitely a budget king there...and the HP Counter is worth looking into.
Harry, I kind like that Simple GPS Stabilized 10 MHZ Oscillator, there,
and for about the same price of the Murphyjunk one...that Simple Stab, GPS
unit with 12 volts....heck, even a wall wort would do...Then a GPS antenna
as with the others I think.

I think the RF stuff is interesting, plus I came across a stash of those
gold Helicopter looking Bipolars and FETs...along with some of those
funky single mica flat RF caps.

Cheers,
Click to expand...

I would not run the one I have on a wall wart

I use a lot of 12 volts in my Amateur Radio hobby so I just went off that supply.

What I have considered it to hook it to a Gell Cell with a float charger
so it will stay on all the time (in case of power outages etc).
They basically get more accurate the longer they are on but all that really
is needed is an hour or so so everything gets up to temperature and stable.

I took the serial output and hooked it to a Raspberry Pi
to act as a time server for my home network.
 
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