Elecraft

GPS Disciplined 10MHZ source from China

Classic

List

Threaded

6 messages Options

Jay Miller

GPS Disciplined 10MHZ source from China

I was curious so I bought a GPS disciplined 10MHz source from China using
the eBay seller "cybereveryday." I have a calibrated scope and a Rubidium
10MHz source. I noticed a frequency offset on three of the WWV frequencies
when I plugged it into the K3 XREF module after getting "GPS Lock" rather
than using my Rubidium lamp standard I measured the 10MHz output from the
GPSDO and it is 10,000,025 Hz. (2.5 PPM) The eBay ad states "Accuracy: than
above OXCO 2 order of magnitude." The point is, even using the K3 zero-beat
method with 15 MHz WWV I can get closer to being dead on frequency than
using this Chinese mfg. GPSDO. Again, Elecraft quality and engineering WINS.

Jay Miller, N4NUI

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [hidden email]

Clay Autery

Re: GPS Disciplined 10MHZ source from China

Need to get that TMP cable (radio to Freq. Ctr) made and get back to the
project of determining exactly how close you can get on average without
an instrument(s).

Pretty sure I can get a lot closer than 25 Hz using my ear.... even my
old aviator's ear.

Glad I chose NOT to try the eBay/Chinese PCB box deals...

______________________
Clay Autery, KY5G

On 5/8/2017 5:26 PM, Jay Miller wrote:

> I was curious so I bought a GPS disciplined 10MHz source from China using
> the eBay seller "cybereveryday." I have a calibrated scope and a Rubidium
> 10MHz source. I noticed a frequency offset on three of the WWV frequencies
> when I plugged it into the K3 XREF module after getting "GPS Lock" rather
> than using my Rubidium lamp standard I measured the 10MHz output from the
> GPSDO and it is 10,000,025 Hz. (2.5 PPM) The eBay ad states "Accuracy: than
> above OXCO 2 order of magnitude." The point is, even using the K3 zero-beat
> method with 15 MHz WWV I can get closer to being dead on frequency than
> using this Chinese mfg. GPSDO. Again, Elecraft quality and engineering WINS.
>
> Jay Miller, N4NUI

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [hidden email]

Elecraft mailing list

Re: GPS Disciplined 10MHZ source from China

In reply to this post by Jay Miller

Mine is from G3RUH http://www.jrmiller.demon.co.uk/projects/ministd/frqstd.htm

he states: The stability as given by the Allan Deviation is typically 5x10-12 at τ=10s.
That figure is 0.05 Hz at 10 GHz and is a remarkably small value.

Using mine as a example I would say the one you have is way off.

I'm not sure what you are using for an Antenna, I'm using an external GPS Timing Antenna

________________________________
From: Jay Miller <[hidden email]>
To: [hidden email]
Sent: Monday, May 8, 2017 6:28 PM
Subject: [Elecraft] GPS Disciplined 10MHZ source from China

I was curious so I bought a GPS disciplined 10MHz source from China using

the eBay seller "cybereveryday." I have a calibrated scope and a Rubidium

10MHz source. I noticed a frequency offset on three of the WWV frequencies

when I plugged it into the K3 XREF module after getting "GPS Lock" rather

than using my Rubidium lamp standard I measured the 10MHz output from the

GPSDO and it is 10,000,025 Hz. (2.5 PPM) The eBay ad states "Accuracy: than

above OXCO 2 order of magnitude." The point is, even using the K3 zero-beat

method with 15 MHz WWV I can get closer to being dead on frequency than

using this Chinese mfg. GPSDO. Again, Elecraft quality and engineering WINS.

Jay Miller, N4NUI

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [hidden email]

Wes Stewart-2

Re: GPS Disciplined 10MHZ source from China

In reply to this post by Jay Miller

How did you measure the GPSDO? Against the Rubidium?

On 5/8/2017 3:26 PM, Jay Miller wrote:

Richard Lamont

Re: GPS Disciplined 10MHZ source from China

In reply to this post by Jay Miller

On 08/05/17 23:26, Jay Miller wrote:
> I was curious so I bought a GPS disciplined 10MHz source from China using
> the eBay seller "cybereveryday." I have a calibrated scope and a Rubidium
> 10MHz source. I noticed a frequency offset on three of the WWV frequencies
> when I plugged it into the K3 XREF module after getting "GPS Lock" rather
> than using my Rubidium lamp standard I measured the 10MHz output from the
> GPSDO and it is 10,000,025 Hz. (2.5 PPM) The eBay ad states "Accuracy: than
> above OXCO 2 order of magnitude." The point is, even using the K3 zero-beat
> method with 15 MHz WWV I can get closer to being dead on frequency than
> using this Chinese mfg. GPSDO. Again, Elecraft quality and engineering WINS.

If you want a good quality 10 MHz GPSDO, I recommend the one made by Leo
Bodnar M0XER. It was reviewed in QST, June 2016.

https://leobodnar.com/

73,
Richard G4DYA

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [hidden email]

Wes Stewart-2

Re: GPS Disciplined 10MHZ source from China

Two Christmases ago, my fiance asked me what I wanted for a gift. On a whim,
without too much study, I said a Bodnar GPSDO. I emailed Leo and inquired about
using the unit as a reference for my SDR-IQ (66.6666 MHz) and a 10 MHz source
for my DG8SAQ network analyzer which can also operate as a frequency counter.

He sent me a screen shot of the software display that showed the variables that
determine the two frequencies. Unfortunately, the calculations to set different
frequencies are obscure. After several inquiries (after the purchase) he sent
me a link to the internal device data sheet (Silicon Labs Si5328) for me to
decipher. QST had this to say about that:

"A couple of caveats: there is currently
no documentation for the unit other than
what Bill Hein has provided on the Force
12 website, and no schematic. Bodnar is
working on an improved version of the
setup software, and documentation may
follow, but I was not able to test the updated
software...."

In reality, there is no updated software and Force 12 is gone.

Summary:

I believe the hardware is fine, however the documentation and communication with
Leo, after the purchase but not before, is iffy.

When locked to GPS it's an excellent frequency reference. When unlocked, it's a
TCXO and not so good. Phase noise isn't stellar.

It's a frequency standard and not a time standard. If you want to set your clock
use WWV or NTP.

Wes N7WS

On 5/9/2017 1:41 AM, Richard Lamont wrote:
>
> If you want a good quality 10 MHz GPSDO, I recommend the one made by Leo
> Bodnar M0XER. It was reviewed in QST, June 2016.
>
> https://leobodnar.com/
>
> 73,
> Richard G4DYA
>

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:[hidden email]

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to [hidden email]