Discussion:
Dual GPSDO - any advantage?
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donald collie
2018-04-10 05:43:25 UTC
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I`ve just bought two GPSDO`s from China @ US$9-50 each [This is not an
error!] They are stated as being new, and use a Trimball dual oven OCXO. I
plan to run these in parallel [2 antennas, 2 feedlines, and 2 GPSDO`s] It`s
been said that a man with two watches is never happy - unless, of course,
they agree with each other ;-). Being identical the outputs should be
coherent, unless one becomes faulty [one advantage of having two - any
discrepancy and you know something must be wrong]], but is there some
crafty way I can squeeze a little more "accuracy" out of two than if I only
used one?
TIA for your comments............................................Donald
Brett Collie ZL4GX

PS : I have no connection to the eBay seller. The US$9-50 seems to include
a basic puck antenna, long downlead, and 4 interseries adaptors
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ewkehren via time-nuts
2018-04-10 10:33:51 UTC
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I bought one too, is a mistake, I am holding my breath  supposedly shipped I previously bought two one for Jürg because it's performance, easier to clean up             Bert Kehren


Sent from my Galaxy Tab® A
-------- Original message --------From: donald collie <***@gmail.com> Date: 4/10/18 1:43 AM (GMT-05:00) To: Discussion of precise time and frequency measurement <time-***@febo.com> Subject: [time-nuts] Dual GPSDO - any advantage?
I`ve just bought two GPSDO`s from China @ US$9-50 each [This is not an
error!] They are stated as being new, and use a Trimball dual oven OCXO. I
plan to run these in parallel [2 antennas, 2 feedlines, and 2 GPSDO`s] It`s
been said that a man with two watches is never happy - unless, of course,
they agree with each other ;-). Being identical the outputs should be
coherent, unless one becomes faulty [one advantage of having two - any
discrepancy and you know something must be wrong]], but is there some
crafty way I can squeeze a little more "accuracy" out of two than if I only
used one?
TIA for your comments............................................Donald
Brett Collie ZL4GX

PS : I have no connection to the eBay seller. The US$9-50 seems to include
a basic puck antenna, long downlead, and 4 interseries adaptors
_______________________________________________
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Tim Shoppa
2018-04-10 10:46:27 UTC
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Most of the Chinese cheapo units have been frequency, not phase locked.

It would be great if you could put the GPSDO outputs into a 2 Channel scope and eyeball them for a while to see if they appear in phase (say plus-minus 20ns) over a few hours.

Tim N3QE

> On Apr 10, 2018, at 1:43 AM, donald collie <***@gmail.com> wrote:
>
> I`ve just bought two GPSDO`s from China @ US$9-50 each [This is not an
> error!] They are stated as being new, and use a Trimball dual oven OCXO. I
> plan to run these in parallel [2 antennas, 2 feedlines, and 2 GPSDO`s] It`s
> been said that a man with two watches is never happy - unless, of course,
> they agree with each other ;-). Being identical the outputs should be
> coherent, unless one becomes faulty [one advantage of having two - any
> discrepancy and you know something must be wrong]], but is there some
> crafty way I can squeeze a little more "accuracy" out of two than if I only
> used one?
> TIA for your comments............................................Donald
> Brett Collie ZL4GX
>
> PS : I have no connection to the eBay seller. The US$9-50 seems to include
> a basic puck antenna, long downlead, and 4 interseries adaptors
> _______________________________________________
> time-nuts mailing list -- time-***@febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
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Florian Teply
2018-04-10 11:00:50 UTC
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Am Tue, 10 Apr 2018 17:43:25 +1200
schrieb donald collie <***@gmail.com>:

> I`ve just bought two GPSDO`s from China @ US$9-50 each [This is not an
> error!] They are stated as being new, and use a Trimball dual oven
> OCXO. I plan to run these in parallel [2 antennas, 2 feedlines, and 2
> GPSDO`s] It`s been said that a man with two watches is never happy -
> unless, of course, they agree with each other ;-). Being identical
> the outputs should be coherent, unless one becomes faulty [one
> advantage of having two - any discrepancy and you know something must
> be wrong]], but is there some crafty way I can squeeze a little more
> "accuracy" out of two than if I only used one?
> TIA for your
> comments............................................Donald Brett
> Collie ZL4GX

well, my experience in that regard is very limited, not to say
nonexisting, thus take the following with a grain of salt.

Assuming a system with two antenna locations where one device would
be fed both antennas, one could potentially employ some extra
correction based on extra knowledge from these two antennas. Even
though the antenna location usually is known with limited accuracy
(error on the order of 1m), the relative location of two antennas can
be known to a much greater accurracy (order of centimetres or better).
If the system can take that extra information into account, one could
maybe gain some extra accuracy for the solution of time/location.
For example, if the antennas are mounted 1m apart, and everything else
being equal, it is a priori clear, that the calculated position for
both antennas should also be 1m apart. As the signal received by both
antennas should be correlated, while their respective noise
contribution is not, one should gain some SNR. If on top of that time
resolution of the receiver system is very high, one could even take the
phase shift between signals received from both signals into account
similar to the way beam steering is done with phased antenna arrays,
just on receive side, again improving SNR.
So far for an integrated system, where all signals arew processed in
one place. Now, as I read it you'll rather have two entirely separate
receiver systems. Here, depending on how it is implemented in the
receivers, one could potentially still gain something extra over a
single unit, but I'd bet this can only be done in postprocessing.
After all, receiver A has no access to the signals as received by
receiver B and vice versa, therefore the spatial relationship can not
be used while deriving the timing solution. Maybe the independent
position solutions could be used to correct the timing solutions after
the fact.

Best regards,
Florian
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Mike Feher
2018-04-10 11:23:29 UTC
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Sounds to me like you have two independent systems. I do not believe they can ever be “coherent”. Regards – Mike



Mike B. Feher, N4FS

89 Arnold Blvd.

Howell NJ 07731

848-245-9115



-----Original Message-----
From: time-nuts <time-nuts-***@febo.com> On Behalf Of donald collie
Sent: Tuesday, April 10, 2018 1:43 AM
To: Discussion of precise time and frequency measurement <time-***@febo.com>
Subject: [time-nuts] Dual GPSDO - any advantage?



I`ve just bought two GPSDO`s from China @ US$9-50 each [This is not an error!] They are stated as being new, and use a Trimball dual oven OCXO. I plan to run these in parallel [2 antennas, 2 feedlines, and 2 GPSDO`s] It`s been said that a man with two watches is never happy - unless, of course, they agree with each other ;-). Being identical the outputs should be coherent, unless one becomes faulty [one advantage of having two - any discrepancy and you know something must be wrong]], but is there some crafty way I can squeeze a little more "accuracy" out of two than if I only used one?

TIA for your comments............................................Donald

Brett Collie ZL4GX



PS : I have no connection to the eBay seller. The US$9-50 seems to include a basic puck antenna, long downlead, and 4 interseries adaptors _______________________________________________

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and follow the instructions there.

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ewkehren via time-nuts
2018-04-10 12:06:50 UTC
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Looking at the pictures it is the same unit I bought. It is not dual oven bit trimble works with LH right now shows tracking 10 satelites.Attached  is data that made  me buy a second one for JÌrg for $ 129  and one more for me for $9.50.What you see is highly filtered data to see long time changes to better understand if analog filtering os possible. Planning on using Wenzel 600 sec. Filter maybe up to 2000 seconds. Board is ready for order.Top plot is my data against my Cs 5061B bottom is original Tbolt against his FTS  Cs. We use 53132 counters.I think  the new one lends it self better for filtering looking at both  with my Tracor, Trimble uses a  much shorter time constant and no short 1E-10 changes you see on our standard units.Will keep you posted         Bert Kehren

Sent from my Galaxy Tab® A
-------- Original message --------From: Tim Shoppa <***@gmail.com> Date: 4/10/18 6:46 AM (GMT-05:00) To: Discussion of precise time and frequency measurement <time-***@febo.com> Subject: Re: [time-nuts] Dual GPSDO - any advantage?
Most of the Chinese cheapo units have been frequency, not phase locked.

It would be great if you could put the GPSDO outputs into a 2 Channel scope and eyeball them for a while to see if they appear in phase (say plus-minus 20ns) over a few hours.

Tim N3QE

> On Apr 10, 2018, at 1:43 AM, donald collie <***@gmail.com> wrote:
>
> I`ve just bought two GPSDO`s from China @ US$9-50 each [This is not an
> error!] They are stated as being new, and use a Trimball dual oven OCXO. I
> plan to run these in parallel [2 antennas, 2 feedlines, and 2 GPSDO`s] It`s
> been said that a man with two watches is never happy - unless, of course,
> they agree with each other ;-). Being identical the outputs should be
> coherent, unless one becomes faulty [one advantage of having two - any
> discrepancy and you know something must be wrong]], but is there some
> crafty way I can squeeze a little more "accuracy" out of two than if I only
> used one?
> TIA for your comments............................................Donald
> Brett Collie ZL4GX
>
> PS : I have no connection to the eBay seller. The US$9-50 seems to include
> a basic puck antenna, long downlead, and 4 interseries adaptors
> _______________________________________________
> time-nuts mailing list -- time-***@febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
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CORNACCHIA via time-nuts
2018-04-10 18:35:39 UTC
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Bert may I ask how you created the charts (what software are you using).Thank You
On Tuesday, April 10, 2018, 9:04:58 a.m. EDT, ewkehren via time-nuts <time-***@febo.com> wrote:

Looking at the pictures it is the same unit I bought. It is not dual oven bit trimble works with LH right now shows tracking 10 satelites.Attached  is data that made  me buy a second one for Jürg for $ 129  and one more for me for $9.50.What you see is highly filtered data to see long time changes to better understand if analog filtering os possible. Planning on using Wenzel 600 sec. Filter maybe up to 2000 seconds. Board is ready for order.Top plot is my data against my Cs 5061B bottom is original Tbolt against his FTS  Cs. We use 53132 counters.I think  the new one lends it self better for filtering looking at both  with my Tracor, Trimble uses a  much shorter time constant and no short 1E-10 changes you see on our standard units.Will keep you posted         Bert Kehren

Sent from my Galaxy Tab® A
-------- Original message --------From: Tim Shoppa <***@gmail.com> Date: 4/10/18  6:46 AM  (GMT-05:00) To: Discussion of precise time and frequency measurement <time-***@febo.com> Subject: Re: [time-nuts] Dual GPSDO - any advantage?
Most of the Chinese cheapo units have been frequency, not phase locked.

It would be great if you could put the GPSDO outputs into a 2 Channel scope and eyeball them for a while to see if they appear in phase (say plus-minus 20ns) over a few hours.

Tim N3QE

> On Apr 10, 2018, at 1:43 AM, donald collie <***@gmail.com> wrote:
>
> I`ve just bought two GPSDO`s from China @ US$9-50 each [This is not an
> error!] They are stated as being new, and use a Trimball dual oven OCXO. I
> plan to run these in parallel [2 antennas, 2 feedlines, and 2 GPSDO`s] It`s
> been said that a man with two watches is never happy - unless, of course,
> they agree with each other ;-). Being identical the outputs should be
> coherent, unless one becomes faulty [one advantage of having two - any
> discrepancy and you know something must be wrong]], but is there some
> crafty way I can squeeze a little more "accuracy" out of two than if I only
> used one?
> TIA for your comments............................................Donald
> Brett Collie ZL4GX
>
> PS : I have no connection to the eBay seller. The US$9-50 seems to include
> a basic puck antenna, long downlead, and 4 interseries adaptors
> _______________________________________________
> time-nuts mailing list -- time-***@febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
_______________________________________________
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ewkehren via time-nuts
2018-04-10 12:25:01 UTC
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I have run 2 Tbolts from thee same antenna  in to my Tracor and see the corrections are in no way correlated.Bert Kehren


Sent from my Galaxy Tab® A
-------- Original message --------From: Florian Teply <***@teply.info> Date: 4/10/18 7:00 AM (GMT-05:00) To: time-***@febo.com Subject: Re: [time-nuts] Dual GPSDO - any advantage?
Am Tue, 10 Apr 2018 17:43:25 +1200
schrieb donald collie <***@gmail.com>:

> I`ve just bought two GPSDO`s from China @ US$9-50 each [This is not an
> error!] They are stated as being new, and use a Trimball dual oven
> OCXO. I plan to run these in parallel [2 antennas, 2 feedlines, and 2
> GPSDO`s] It`s been said that a man with two watches is never happy -
> unless, of course, they agree with each other ;-). Being identical
> the outputs should be coherent, unless one becomes faulty [one
> advantage of having two - any discrepancy and you know something must
> be wrong]], but is there some crafty way I can squeeze a little more
> "accuracy" out of two than if I only used one?
> TIA for your
> comments............................................Donald Brett
> Collie ZL4GX

well, my experience in that regard is very limited, not to say
nonexisting, thus take the following with a grain of salt.

Assuming a system with two antenna locations where one device would
be fed both antennas, one could potentially employ some extra
correction based on extra knowledge from these two antennas. Even
though the antenna location usually is known with limited accuracy
(error on the order of 1m), the relative location of two antennas can
be known to a much greater accurracy (order of centimetres or better).
If the system can take that extra information into account, one could
maybe gain some extra accuracy for the solution of time/location.
For example, if the antennas are mounted 1m apart, and everything else
being equal, it is a priori clear, that the calculated position for
both antennas should also be 1m apart. As the signal received by both
antennas should be correlated, while their respective noise
contribution is not, one should gain some SNR. If on top of that time
resolution of the receiver system is very high, one could even take the
phase shift between signals received from both signals into account
similar to the way beam steering is done with phased antenna arrays,
just on receive side, again improving SNR.
So far for an integrated system, where all signals arew processed in
one place. Now, as I read it you'll rather have two entirely separate
receiver systems. Here, depending on how it is implemented in the
receivers, one could potentially  still gain something extra over a
single unit, but I'd bet this can only be done in postprocessing.
After all, receiver A has no access to the signals as received by
receiver B and vice versa, therefore the spatial relationship can not
be used while deriving the timing solution. Maybe the independent
position solutions could be used to correct the timing solutions after
the fact.

Best regards,
Florian
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Bob kb8tq
2018-04-10 13:52:31 UTC
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Hi

Simple answer is that the “simple” approaches don’t do much to improve things.
Errors are indeed un-correlated, even off of the same antenna. You *could*
average the result off of the two. That might improve things by sqrt(2). My
experience is that the bumps and lumps (when they do occur) are not the sort
of thing that averages out nicely…..

Bob

> On Apr 10, 2018, at 1:43 AM, donald collie <***@gmail.com> wrote:
>
> I`ve just bought two GPSDO`s from China @ US$9-50 each [This is not an
> error!] They are stated as being new, and use a Trimball dual oven OCXO. I
> plan to run these in parallel [2 antennas, 2 feedlines, and 2 GPSDO`s] It`s
> been said that a man with two watches is never happy - unless, of course,
> they agree with each other ;-). Being identical the outputs should be
> coherent, unless one becomes faulty [one advantage of having two - any
> discrepancy and you know something must be wrong]], but is there some
> crafty way I can squeeze a little more "accuracy" out of two than if I only
> used one?
> TIA for your comments............................................Donald
> Brett Collie ZL4GX
>
> PS : I have no connection to the eBay seller. The US$9-50 seems to include
> a basic puck antenna, long downlead, and 4 interseries adaptors
> _______________________________________________
> time-nuts mailing list -- time-***@febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.

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Clint Jay
2018-04-10 14:32:56 UTC
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Ahh, I've found the listing, has anyone received one?

I hate to say this but I'm highly sceptical that they will ever turn up,
looks and smells very much like the standard eBay scam to me.





On 10 April 2018 at 14:52, Bob kb8tq <***@n1k.org> wrote:

> Hi
>
> Simple answer is that the “simple” approaches don’t do much to improve
> things.
> Errors are indeed un-correlated, even off of the same antenna. You *could*
> average the result off of the two. That might improve things by sqrt(2). My
> experience is that the bumps and lumps (when they do occur) are not the
> sort
> of thing that averages out nicely…..
>
> Bob
>
> > On Apr 10, 2018, at 1:43 AM, donald collie <***@gmail.com>
> wrote:
> >
> > I`ve just bought two GPSDO`s from China @ US$9-50 each [This is not an
> > error!] They are stated as being new, and use a Trimball dual oven OCXO.
> I
> > plan to run these in parallel [2 antennas, 2 feedlines, and 2 GPSDO`s]
> It`s
> > been said that a man with two watches is never happy - unless, of course,
> > they agree with each other ;-). Being identical the outputs should be
> > coherent, unless one becomes faulty [one advantage of having two - any
> > discrepancy and you know something must be wrong]], but is there some
> > crafty way I can squeeze a little more "accuracy" out of two than if I
> only
> > used one?
> > TIA for your comments............................................Donald
> > Brett Collie ZL4GX
> >
> > PS : I have no connection to the eBay seller. The US$9-50 seems to
> include
> > a basic puck antenna, long downlead, and 4 interseries adaptors
> > _______________________________________________
> > time-nuts mailing list -- time-***@febo.com
> > To unsubscribe, go to https://www.febo.com/cgi-bin/
> mailman/listinfo/time-nuts
> > and follow the instructions there.
>
> _______________________________________________
> time-nuts mailing list -- time-***@febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/
> mailman/listinfo/time-nuts
> and follow the instructions there.
>



--
Clint. M0UAW IO83

*No trees were harmed in the sending of this mail. However, a large number
of electrons were greatly inconvenienced.*
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Bob kb8tq
2018-04-10 15:08:18 UTC
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Hi

I certainly would not pay with anything other than PayPal. There is a very
real risk …..

Bob

> On Apr 10, 2018, at 10:32 AM, Clint Jay <***@gmail.com> wrote:
>
> Ahh, I've found the listing, has anyone received one?
>
> I hate to say this but I'm highly sceptical that they will ever turn up,
> looks and smells very much like the standard eBay scam to me.
>
>
>
>
>
> On 10 April 2018 at 14:52, Bob kb8tq <***@n1k.org> wrote:
>
>> Hi
>>
>> Simple answer is that the “simple” approaches don’t do much to improve
>> things.
>> Errors are indeed un-correlated, even off of the same antenna. You *could*
>> average the result off of the two. That might improve things by sqrt(2). My
>> experience is that the bumps and lumps (when they do occur) are not the
>> sort
>> of thing that averages out nicely…..
>>
>> Bob
>>
>>> On Apr 10, 2018, at 1:43 AM, donald collie <***@gmail.com>
>> wrote:
>>>
>>> I`ve just bought two GPSDO`s from China @ US$9-50 each [This is not an
>>> error!] They are stated as being new, and use a Trimball dual oven OCXO.
>> I
>>> plan to run these in parallel [2 antennas, 2 feedlines, and 2 GPSDO`s]
>> It`s
>>> been said that a man with two watches is never happy - unless, of course,
>>> they agree with each other ;-). Being identical the outputs should be
>>> coherent, unless one becomes faulty [one advantage of having two - any
>>> discrepancy and you know something must be wrong]], but is there some
>>> crafty way I can squeeze a little more "accuracy" out of two than if I
>> only
>>> used one?
>>> TIA for your comments............................................Donald
>>> Brett Collie ZL4GX
>>>
>>> PS : I have no connection to the eBay seller. The US$9-50 seems to
>> include
>>> a basic puck antenna, long downlead, and 4 interseries adaptors
>>> _______________________________________________
>>> time-nuts mailing list -- time-***@febo.com
>>> To unsubscribe, go to https://www.febo.com/cgi-bin/
>> mailman/listinfo/time-nuts
>>> and follow the instructions there.
>>
>> _______________________________________________
>> time-nuts mailing list -- time-***@febo.com
>> To unsubscribe, go to https://www.febo.com/cgi-bin/
>> mailman/listinfo/time-nuts
>> and follow the instructions there.
>>
>
>
>
> --
> Clint. M0UAW IO83
>
> *No trees were harmed in the sending of this mail. However, a large number
> of electrons were greatly inconvenienced.*
> _______________________________________________
> time-nuts mailing list -- time-***@febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.

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Dr. David Kirkby
2018-04-10 15:23:39 UTC
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On 10 April 2018 at 15:32, Clint Jay <***@gmail.com> wrote:

> Ahh, I've found the listing, has anyone received one?
>
> I hate to say this but I'm highly sceptical that they will ever turn up,
> looks and smells very much like the standard eBay scam to me.
>
--

> Clint. M0UAW IO83
>


I'm VERY skeptical too of the item

https://www.ebay.com/itm/Trimble-GPS-Receiver-GPSDO-10MHz-1PPS-GPS-Disciplined-Clock-sine-and-square-wave/273145006434

I have bought 10, on the assumption if they don't show up, I will get my
money back. Note the seller has a feedback of zero, and had not been
registered that long. So I'm thinking there's a 95% chance its a scam.

Also listed by the same seller is a rubidium source

https://www.ebay.com/itm/New-FE-5650A-OPTION-58-RUBIDIUM-FREQUENCY-STD-FREQUENCY-ELECTRONICS-INC/273145001650

which looking nothing like one.

Perhaps with hindsight, I wish I had not ordered 10, but then I would kick
myself if I did not order them, and find out later they are genuine.

Dave
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Dr. David Kirkby
2018-04-10 15:59:03 UTC
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On 10 April 2018 at 16:23, Dr. David Kirkby <***@kirkbymicrowave.co.uk>
wrote:

> On 10 April 2018 at 15:32, Clint Jay <***@gmail.com> wrote:
>
>> Ahh, I've found the listing, has anyone received one?
>>
>> I hate to say this but I'm highly sceptical that they will ever turn up,
>> looks and smells very much like the standard eBay scam to me.
>>
> --
>
>> Clint. M0UAW IO83
>>
>
>
> I'm VERY skeptical too of the item
>


The more I look at this, the more I think it is a scam.

* Description says orders shipped after April 2016 will be a new design,
yet the seller was not registered until 27th February 2018 - almost 2 years
later.
* Feedback is zero.

I phoned eBay. The guy I spoke too was highly suspicious too, and has past
it along to a team that deals with possible scams.

Dave
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donald collie
2018-04-10 15:56:37 UTC
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Raw Message
I have the Chinapost tracking numbers, so I don`t think it`s a scam - just
real good value. I have the eBay guarantee, anyway. I`m just looking for a
superior frequency standard at the moment, but the timenut bug might bight.
How could I take the average of two [now three]. A man with three watches.
. . . Cheers!... Don C.

<http://www.avg.com/email-signature?utm_medium=email&utm_source=link&utm_campaign=sig-email&utm_content=webmail>
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On Wed, Apr 11, 2018 at 2:32 AM, Clint Jay <***@gmail.com> wrote:

> Ahh, I've found the listing, has anyone received one?
>
> I hate to say this but I'm highly sceptical that they will ever turn up,
> looks and smells very much like the standard eBay scam to me.
>
>
>
>
>
> On 10 April 2018 at 14:52, Bob kb8tq <***@n1k.org> wrote:
>
> > Hi
> >
> > Simple answer is that the “simple” approaches don’t do much to improve
> > things.
> > Errors are indeed un-correlated, even off of the same antenna. You
> *could*
> > average the result off of the two. That might improve things by sqrt(2).
> My
> > experience is that the bumps and lumps (when they do occur) are not the
> > sort
> > of thing that averages out nicely…..
> >
> > Bob
> >
> > > On Apr 10, 2018, at 1:43 AM, donald collie <***@gmail.com>
> > wrote:
> > >
> > > I`ve just bought two GPSDO`s from China @ US$9-50 each [This is not an
> > > error!] They are stated as being new, and use a Trimball dual oven
> OCXO.
> > I
> > > plan to run these in parallel [2 antennas, 2 feedlines, and 2 GPSDO`s]
> > It`s
> > > been said that a man with two watches is never happy - unless, of
> course,
> > > they agree with each other ;-). Being identical the outputs should be
> > > coherent, unless one becomes faulty [one advantage of having two - any
> > > discrepancy and you know something must be wrong]], but is there some
> > > crafty way I can squeeze a little more "accuracy" out of two than if I
> > only
> > > used one?
> > > TIA for your comments......................
> ......................Donald
> > > Brett Collie ZL4GX
> > >
> > > PS : I have no connection to the eBay seller. The US$9-50 seems to
> > include
> > > a basic puck antenna, long downlead, and 4 interseries adaptors
> > > _______________________________________________
> > > time-nuts mailing list -- time-***@febo.com
> > > To unsubscribe, go to https://www.febo.com/cgi-bin/
> > mailman/listinfo/time-nuts
> > > and follow the instructions there.
> >
> > _______________________________________________
> > time-nuts mailing list -- time-***@febo.com
> > To unsubscribe, go to https://www.febo.com/cgi-bin/
> > mailman/listinfo/time-nuts
> > and follow the instructions there.
> >
>
>
>
> --
> Clint. M0UAW IO83
>
> *No trees were harmed in the sending of this mail. However, a large number
> of electrons were greatly inconvenienced.*
> _______________________________________________
> time-nuts mailing list -- time-***@febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/
> mailman/listinfo/time-nuts
> and follow the instructions there.
>
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Dr. David Kirkby
2018-04-10 19:29:44 UTC
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On 10 April 2018 at 16:56, donald collie <***@gmail.com> wrote:

> I have the Chinapost tracking numbers, so I don`t think it`s a scam - just
> real good value.


I hope you are right, but I doubt you are.

It is not uncommon to be sent fake tracking numbers.

I was 99% sure a Keithley 2002 8.5 digit meter for £900 was a scam, but
decided to play along with it, just in case it was not. The seller claimed
to have sent it, send me a FedEx tracking number, but said if he did not
receive payment by bank transfer within 24 hours he would cancel the
shipment. The tracking number was NOT to the real FedEx site, but something
made to look like FedEx.

Even if you have the real Chinese post office tracking number, it could be
the same number sent to 100 people. I doubt it has your detailed location
on it.

I hope you are right, and they are a good buy, as I bought 10 of them. But
I doubt they are real. I'm 99% sure they are a scam, but are not bothered,
as a scam like that would easily result in one willing an eBay dispute.

Dave
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gandalfg8--- via time-nuts
2018-04-10 14:13:28 UTC
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Raw Message
Is this auction # 273145006434, actually showing at $9.77 here in the UK, and from a recently registered zero rated seller?

If so, and given that the auction text, and perhaps the photos too, seem to be taken from one or more of Bob Mokia's
auctions dating back a couple of years or so, and that this price is approximately $100 below the norm, perhaps
a degree of caution might be worthwhile.

It's either a very sad mistake, from the seller's point of view anyway, or perhaps something a little more devious!

Nigel, GM8PZR


I`ve just bought two GPSDO`s from China @ US$9-50 each [This is not an
error!] They are stated as being new, and use a Trimball dual oven OCXO. I
plan to run these in parallel [2 antennas, 2 feedlines, and 2 GPSDO`s] It`s
been said that a man with two watches is never happy - unless, of course,
they agree with each other ;-). Being identical the outputs should be
coherent, unless one becomes faulty [one advantage of having two - any
discrepancy and you know something must be wrong]], but is there some
crafty way I can squeeze a little more "accuracy" out of two than if I only
used one?
TIA for your comments............................................Donald
Brett Collie ZL4GX

PS : I have no connection to the eBay seller. The US$9-50 seems to include
a basic puck antenna, long downlead, and 4 interseries adaptors



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Richard Solomon
2018-04-10 15:41:02 UTC
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As we say in the world of DX'ing (Ham Radio) ...


"Work First Worry Later"


I just ordered two of them. If they are bogus, e-Bay will make good on them.


73, Dick, W1KSZ


Sent from Outlook<http://aka.ms/weboutlook>
________________________________
From: time-nuts <time-nuts-***@febo.com> on behalf of gandalfg8--- via time-nuts <time-***@febo.com>
Sent: Tuesday, April 10, 2018 7:13:28 AM
To: time-***@febo.com
Subject: [time-nuts] Dual GPSDO - any advantage?




Is this auction # 273145006434, actually showing at $9.77 here in the UK, and from a recently registered zero rated seller?

If so, and given that the auction text, and perhaps the photos too, seem to be taken from one or more of Bob Mokia's
auctions dating back a couple of years or so, and that this price is approximately $100 below the norm, perhaps
a degree of caution might be worthwhile.

It's either a very sad mistake, from the seller's point of view anyway, or perhaps something a little more devious!

Nigel, GM8PZR


I`ve just bought two GPSDO`s from China @ US$9-50 each [This is not an
error!] They are stated as being new, and use a Trimball dual oven OCXO. I
plan to run these in parallel [2 antennas, 2 feedlines, and 2 GPSDO`s] It`s
been said that a man with two watches is never happy - unless, of course,
they agree with each other ;-). Being identical the outputs should be
coherent, unless one becomes faulty [one advantage of having two - any
discrepancy and you know something must be wrong]], but is there some
crafty way I can squeeze a little more "accuracy" out of two than if I only
used one?
TIA for your comments............................................Donald
Brett Collie ZL4GX

PS : I have no connection to the eBay seller. The US$9-50 seems to include
a basic puck antenna, long downlead, and 4 interseries adaptors



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Clint Jay
2018-04-10 16:11:59 UTC
Reply
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Raw Message
Sad to say I think I was right, the listings have been pulled already and
the seller now has zero items for sale.

Get those paypal refund cases logged.

On 10 April 2018 at 15:13, gandalfg8--- via time-nuts <time-***@febo.com>
wrote:

>
>
>
> Is this auction # 273145006434, actually showing at $9.77 here in the UK,
> and from a recently registered zero rated seller?
>
> If so, and given that the auction text, and perhaps the photos too, seem
> to be taken from one or more of Bob Mokia's
> auctions dating back a couple of years or so, and that this price is
> approximately $100 below the norm, perhaps
> a degree of caution might be worthwhile.
>
> It's either a very sad mistake, from the seller's point of view anyway, or
> perhaps something a little more devious!
>
> Nigel, GM8PZR
>
>
> I`ve just bought two GPSDO`s from China @ US$9-50 each [This is not an
> error!] They are stated as being new, and use a Trimball dual oven OCXO. I
> plan to run these in parallel [2 antennas, 2 feedlines, and 2 GPSDO`s] It`s
> been said that a man with two watches is never happy - unless, of course,
> they agree with each other ;-). Being identical the outputs should be
> coherent, unless one becomes faulty [one advantage of having two - any
> discrepancy and you know something must be wrong]], but is there some
> crafty way I can squeeze a little more "accuracy" out of two than if I only
> used one?
> TIA for your comments............................................Donald
> Brett Collie ZL4GX
>
> PS : I have no connection to the eBay seller. The US$9-50 seems to include
> a basic puck antenna, long downlead, and 4 interseries adaptors
>
>
>
> _______________________________________________
> time-nuts mailing list -- time-***@febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/
> mailman/listinfo/time-nuts
> and follow the instructions there.
>



--
Clint. M0UAW IO83

*No trees were harmed in the sending of this mail. However, a large number
of electrons were greatly inconvenienced.*
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Dr. David Kirkby
2018-04-10 19:24:41 UTC
Reply
Permalink
Raw Message
On 10 April 2018 at 17:11, Clint Jay <***@gmail.com> wrote:

> Sad to say I think I was right, the listings have been pulled already and
> the seller now has zero items for sale.
>

The listing has not been pulled. Yes the seller has 0 to sell, but because
he has sold out of the 100. I still have the purchase in my purchase
history, and no messages from eBay about fraud.

>
> Get those paypal refund cases logged.
>

One would need to wait until they don't arrive. Luckily they were not much.

Then it is better to complain to eBay first. If you don't get any
satisfaction from eBay, then you can go to PayPal. But by going directly to
PayPal, you will have lost the chance to get a refund via eBay. So the
sensible order to try to get refunds is

1) eBay
2) PayPal
3) Chargeback on credit card.

Never advance to stage PayPal unless you have exhaused attempts at eBay.
Never make a chargeback unless you have exhaused atttempts at both eBay and
PayPal.

Sometimes it can be a bit of an uphill struggle to get refunds from eBay
for dodgy sellers, but in this case it should be fairly easy if the goods
don't arrive. On the off-chance they do, we have scored well.


Clint. M0UAW IO83
>


Dave G8WRB.
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Richard Solomon
2018-04-10 21:25:58 UTC
Reply
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Raw Message
In the past I have had excellent experiences with e-Bay when it comes to

bad sellers. If the parts never arrive, there is no question, I got a refund.

If the parts were not as described, still no problems.


e-Bay seems to have been more on the side of the Buyer lately. A far cry

from their early days when the Seller's word was Gospel.


73, Dick, W1KSZ


Sent from Outlook<http://aka.ms/weboutlook>
________________________________
From: time-nuts <time-nuts-***@febo.com> on behalf of Dr. David Kirkby <***@kirkbymicrowave.co.uk>
Sent: Tuesday, April 10, 2018 12:24:41 PM
To: Discussion of precise time and frequency measurement
Cc: ***@aol.com
Subject: Re: [time-nuts] Dual GPSDO - any advantage?

On 10 April 2018 at 17:11, Clint Jay <***@gmail.com> wrote:

> Sad to say I think I was right, the listings have been pulled already and
> the seller now has zero items for sale.
>

The listing has not been pulled. Yes the seller has 0 to sell, but because
he has sold out of the 100. I still have the purchase in my purchase
history, and no messages from eBay about fraud.

>
> Get those paypal refund cases logged.
>

One would need to wait until they don't arrive. Luckily they were not much.

Then it is better to complain to eBay first. If you don't get any
satisfaction from eBay, then you can go to PayPal. But by going directly to
PayPal, you will have lost the chance to get a refund via eBay. So the
sensible order to try to get refunds is

1) eBay
2) PayPal
3) Chargeback on credit card.

Never advance to stage PayPal unless you have exhaused attempts at eBay.
Never make a chargeback unless you have exhaused atttempts at both eBay and
PayPal.

Sometimes it can be a bit of an uphill struggle to get refunds from eBay
for dodgy sellers, but in this case it should be fairly easy if the goods
don't arrive. On the off-chance they do, we have scored well.


Clint. M0UAW IO83
>


Dave G8WRB.
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Heinz Breuer
2018-04-11 08:14:24 UTC
Reply
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Raw Message
The seller added 100 pieces. At this moment 110 are sold.
Auction #273145006434

Well it sounds too good to be true but I ordered 4 pieces just in case that it is real.

With PayPal there is little risk.
vy 73 Heinz DH2FA, KM5VT

Von meinem iPhone gesendet

> Am 10.04.2018 um 23:25 schrieb Richard Solomon <***@outlook.com>:
>
> In the past I have had excellent experiences with e-Bay when it comes to
>
> bad sellers. If the parts never arrive, there is no question, I got a refund.
>
> If the parts were not as described, still no problems.
>
>
> e-Bay seems to have been more on the side of the Buyer lately. A far cry
>
> from their early days when the Seller's word was Gospel.
>
>
> 73, Dick, W1KSZ
>
>
> Sent from Outlook<http://aka.ms/weboutlook>
> ________________________________
> From: time-nuts <time-nuts-***@febo.com> on behalf of Dr. David Kirkby <***@kirkbymicrowave.co.uk>
> Sent: Tuesday, April 10, 2018 12:24:41 PM
> To: Discussion of precise time and frequency measurement
> Cc: ***@aol.com
> Subject: Re: [time-nuts] Dual GPSDO - any advantage?
>
>> On 10 April 2018 at 17:11, Clint Jay <***@gmail.com> wrote:
>>
>> Sad to say I think I was right, the listings have been pulled already and
>> the seller now has zero items for sale.
>
> The listing has not been pulled. Yes the seller has 0 to sell, but because
> he has sold out of the 100. I still have the purchase in my purchase
> history, and no messages from eBay about fraud.
>
>>
>> Get those paypal refund cases logged.
>
> One would need to wait until they don't arrive. Luckily they were not much.
>
> Then it is better to complain to eBay first. If you don't get any
> satisfaction from eBay, then you can go to PayPal. But by going directly to
> PayPal, you will have lost the chance to get a refund via eBay. So the
> sensible order to try to get refunds is
>
> 1) eBay
> 2) PayPal
> 3) Chargeback on credit card.
>
> Never advance to stage PayPal unless you have exhaused attempts at eBay.
> Never make a chargeback unless you have exhaused atttempts at both eBay and
> PayPal.
>
> Sometimes it can be a bit of an uphill struggle to get refunds from eBay
> for dodgy sellers, but in this case it should be fairly easy if the goods
> don't arrive. On the off-chance they do, we have scored well.
>
>
> Clint. M0UAW IO83
>
>
> Dave G8WRB.
> _______________________________________________
> time-nuts mailing list -- time-***@febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
> _______________________________________________
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> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.

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W7SLS - Scott Scheirman
2018-04-10 16:44:58 UTC
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Raw Message
I ordered 2. We shall see
Scott
No connection with seller(s)

Sent from my iPhone

> On Apr 10, 2018, at 7:13 AM, gandalfg8--- via time-nuts <time-***@febo.com> wrote:
>
>
>
>
> Is this auction # 273145006434, actually showing at $9.77 here in the UK, and from a recently registered zero rated seller?
>
> If so, and given that the auction text, and perhaps the photos too, seem to be taken from one or more of Bob Mokia's
> auctions dating back a couple of years or so, and that this price is approximately $100 below the norm, perhaps
> a degree of caution might be worthwhile.
>
> It's either a very sad mistake, from the seller's point of view anyway, or perhaps something a little more devious!
>
> Nigel, GM8PZR
>
>
> I`ve just bought two GPSDO`s from China @ US$9-50 each [This is not an
> error!] They are stated as being new, and use a Trimball dual oven OCXO. I
> plan to run these in parallel [2 antennas, 2 feedlines, and 2 GPSDO`s] It`s
> been said that a man with two watches is never happy - unless, of course,
> they agree with each other ;-). Being identical the outputs should be
> coherent, unless one becomes faulty [one advantage of having two - any
> discrepancy and you know something must be wrong]], but is there some
> crafty way I can squeeze a little more "accuracy" out of two than if I only
> used one?
> TIA for your comments............................................Donald
> Brett Collie ZL4GX
>
> PS : I have no connection to the eBay seller. The US$9-50 seems to include
> a basic puck antenna, long downlead, and 4 interseries adaptors
>
>
>
> _______________________________________________
> time-nuts mailing list -- time-***@febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
_______________________________________________
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and follow the instructions there.
Bob kb8tq
2018-04-10 18:14:04 UTC
Reply
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Raw Message
Hi

Looks like 100 is all he had (or all he put up on this auction). It will be interesting to see what
(if anything) we all get …..

Bob

> On Apr 10, 2018, at 12:44 PM, W7SLS - Scott Scheirman <***@gmail.com> wrote:
>
> I ordered 2. We shall see
> Scott
> No connection with seller(s)
>
> Sent from my iPhone
>
>> On Apr 10, 2018, at 7:13 AM, gandalfg8--- via time-nuts <time-***@febo.com> wrote:
>>
>>
>>
>>
>> Is this auction # 273145006434, actually showing at $9.77 here in the UK, and from a recently registered zero rated seller?
>>
>> If so, and given that the auction text, and perhaps the photos too, seem to be taken from one or more of Bob Mokia's
>> auctions dating back a couple of years or so, and that this price is approximately $100 below the norm, perhaps
>> a degree of caution might be worthwhile.
>>
>> It's either a very sad mistake, from the seller's point of view anyway, or perhaps something a little more devious!
>>
>> Nigel, GM8PZR
>>
>>
>> I`ve just bought two GPSDO`s from China @ US$9-50 each [This is not an
>> error!] They are stated as being new, and use a Trimball dual oven OCXO. I
>> plan to run these in parallel [2 antennas, 2 feedlines, and 2 GPSDO`s] It`s
>> been said that a man with two watches is never happy - unless, of course,
>> they agree with each other ;-). Being identical the outputs should be
>> coherent, unless one becomes faulty [one advantage of having two - any
>> discrepancy and you know something must be wrong]], but is there some
>> crafty way I can squeeze a little more "accuracy" out of two than if I only
>> used one?
>> TIA for your comments............................................Donald
>> Brett Collie ZL4GX
>>
>> PS : I have no connection to the eBay seller. The US$9-50 seems to include
>> a basic puck antenna, long downlead, and 4 interseries adaptors
>>
>>
>>
>> _______________________________________________
>> time-nuts mailing list -- time-***@febo.com
>> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>> and follow the instructions there.
> _______________________________________________
> time-nuts mailing list -- time-***@febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.

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CORNACCHIA via time-nuts
2018-04-10 18:17:33 UTC
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Raw Message
How did You Pay for them, I cannot make a payment????????
On Tuesday, April 10, 2018, 2:01:41 p.m. EDT, W7SLS - Scott Scheirman <***@gmail.com> wrote:

I ordered 2.  We shall see
Scott
No connection with seller(s)

Sent from my iPhone

> On Apr 10, 2018, at 7:13 AM, gandalfg8--- via time-nuts <time-***@febo.com> wrote:
>
>
>
>
> Is this auction # 273145006434, actually showing at $9.77 here in the UK, and from a recently registered zero rated seller?
>
> If so, and given that the auction text, and perhaps the photos too, seem to be taken from one or more of Bob Mokia's
> auctions dating back a couple of years or so, and that this price is approximately $100 below the norm, perhaps
> a degree of caution might be worthwhile.
>
> It's either a very sad mistake, from the seller's point of view anyway, or perhaps something a little more devious!
>
> Nigel, GM8PZR
>
>
> I`ve just bought two GPSDO`s from China @ US$9-50 each [This is not an
> error!] They are stated as being new, and use a Trimball dual oven OCXO. I
> plan to run these in parallel [2 antennas, 2 feedlines, and 2 GPSDO`s] It`s
> been said that a man with two watches is never happy - unless, of course,
> they agree with each other ;-). Being identical the outputs should be
> coherent, unless one becomes faulty [one advantage of having two - any
> discrepancy and you know something must be wrong]], but is there some
> crafty way I can squeeze a little more "accuracy" out of two than if I only
> used one?
> TIA for your comments............................................Donald
> Brett Collie ZL4GX
>
> PS : I have no connection to the eBay seller. The US$9-50 seems to include
> a basic puck antenna, long downlead, and 4 interseries adaptors
>
>
>
> _______________________________________________
> time-nuts mailing list -- time-***@febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
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ewkehren via time-nuts
2018-04-10 15:35:43 UTC
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Raw Message
Most likely but PayPal will have to get involved since there are more than one of usBert Kehren


Sent from my Galaxy Tab® A
-------- Original message --------From: Clint Jay <***@gmail.com> Date: 4/10/18 10:32 AM (GMT-05:00) To: Discussion of precise time and frequency measurement <time-***@febo.com> Subject: Re: [time-nuts] Dual GPSDO - any advantage?
Ahh, I've found the listing, has anyone received one?

I hate to say this but I'm highly sceptical that they will ever turn up,
looks and smells very much like the standard eBay scam to me.





On 10 April 2018 at 14:52, Bob kb8tq <***@n1k.org> wrote:

> Hi
>
> Simple answer is that the “simple” approaches don’t do much to improve
> things.
> Errors are indeed un-correlated, even off of the same antenna. You *could*
> average the result off of the two. That might improve things by sqrt(2). My
> experience is that the bumps and lumps (when they do occur) are not the
> sort
> of thing that averages out nicely…..
>
> Bob
>
> > On Apr 10, 2018, at 1:43 AM, donald collie <***@gmail.com>
> wrote:
> >
> > I`ve just bought two GPSDO`s from China @ US$9-50 each [This is not an
> > error!] They are stated as being new, and use a Trimball dual oven OCXO.
> I
> > plan to run these in parallel [2 antennas, 2 feedlines, and 2 GPSDO`s]
> It`s
> > been said that a man with two watches is never happy - unless, of course,
> > they agree with each other ;-). Being identical the outputs should be
> > coherent, unless one becomes faulty [one advantage of having two - any
> > discrepancy and you know something must be wrong]], but is there some
> > crafty way I can squeeze a little more "accuracy" out of two than if I
> only
> > used one?
> > TIA for your comments............................................Donald
> > Brett Collie ZL4GX
> >
> > PS : I have no connection to the eBay seller. The US$9-50 seems to
> include
> > a basic puck antenna, long downlead, and 4 interseries adaptors
> > _______________________________________________
> > time-nuts mailing list -- time-***@febo.com
> > To unsubscribe, go to https://www.febo.com/cgi-bin/
> mailman/listinfo/time-nuts
> > and follow the instructions there.
>
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>



--
Clint. M0UAW IO83

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ewkehren via time-nuts
2018-04-10 19:31:36 UTC
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Jürg will have to explain he is in Switzerland  will be tomorrowBert


Sent from my Galaxy Tab® A
-------- Original message --------From: CORNACCHIA via time-nuts <time-***@febo.com> Date: 4/10/18 2:35 PM (GMT-05:00) To: ewkehren via time-nuts <time-***@febo.com> Subject: Re: [time-nuts] Dual GPSDO - any advantage?
Bert may I ask how you created the charts (what software are you using).Thank You
    On Tuesday, April 10, 2018, 9:04:58 a.m. EDT, ewkehren via time-nuts <time-***@febo.com> wrote: 

Looking at the pictures it is the same unit I bought. It is not dual oven bit trimble works with LH right now shows tracking 10 satelites.Attached  is data that made  me buy a second one for Jürg for $ 129  and one more for me for $9.50.What you see is highly filtered data to see long time changes to better understand if analog filtering os possible. Planning on using Wenzel 600 sec. Filter maybe up to 2000 seconds. Board is ready for order.Top plot is my data against my Cs 5061B bottom is original Tbolt against his FTS  Cs. We use 53132 counters.I think  the new one lends it self better for filtering looking at both  with my Tracor, Trimble uses a  much shorter time constant and no short 1E-10 changes you see on our standard units.Will keep you posted         Bert Kehren

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-------- Original message --------From: Tim Shoppa <***@gmail.com> Date: 4/10/18  6:46 AM  (GMT-05:00) To: Discussion of precise time and frequency measurement <time-***@febo.com> Subject: Re: [time-nuts] Dual GPSDO - any advantage?
Most of the Chinese cheapo units have been frequency, not phase locked.

It would be great if you could put the GPSDO outputs into a 2 Channel scope and eyeball them for a while to see if they appear in phase (say plus-minus 20ns) over a few hours.

Tim N3QE

> On Apr 10, 2018, at 1:43 AM, donald collie <***@gmail.com> wrote:
>
> I`ve just bought two GPSDO`s from China @ US$9-50 each [This is not an
> error!] They are stated as being new, and use a Trimball dual oven OCXO. I
> plan to run these in parallel [2 antennas, 2 feedlines, and 2 GPSDO`s] It`s
> been said that a man with two watches is never happy - unless, of course,
> they agree with each other ;-). Being identical the outputs should be
> coherent, unless one becomes faulty [one advantage of having two - any
> discrepancy and you know something must be wrong]], but is there some
> crafty way I can squeeze a little more "accuracy" out of two than if I only
> used one?
> TIA for your comments............................................Donald
> Brett Collie ZL4GX
>
> PS : I have no connection to the eBay seller. The US$9-50 seems to include
> a basic puck antenna, long downlead, and 4 interseries adaptors
> _______________________________________________
> time-nuts mailing list -- time-***@febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
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gandalfg8--- via time-nuts
2018-04-10 20:28:40 UTC
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Unless I copied the number incorrectly earlier it does seem likely that Ebay has pulled that auction.

It may still be showing up to those who "bought" them but a straight search on that number returns nothing,
either in completed or running listings, nor does it show up now in searches for "Trimble GPSDO" which is how I found it earlier.

If anyone's interested, and in case there's still any doubts, one version of the Bob Mokia listing under his Ebay ID of amoj1010, that was copied photos and all to provide this auction, is still current and is # 252162780444.

Nigel, GM8PZR


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John Green
2018-04-11 00:51:18 UTC
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With regard to two GPSDOs, it is an interesting experiment. I have two
Tbolts, both 2.2 firmware, both fed from the same antenna, both with
factory default settings, and I see differences. They are about 2 feet
apart on my bench and everything is pretty stable, +/- 20 nS or so until
the heat kicks on. Then, the time difference between the two 10 MHz outputs
goes wild. Go figure.
Regarding eBay and deadbeat sellers, they are much better than in the past.
I got ripped off by an unscrupulous seller some years ago and eBay just
told me they had closed their eBay account. Today, If I don't get my item
fairly fast, I file a complaint right away. An unscrupulous seller will try
a delaying tactic to get you to wait until the time for eBay to do anything
has run out. I had an issue with a Chinese seller once and PayPal told me
they couldn't issue a refund because they didn't have access to the
seller's bank account.
Yeah, sure. The worst abuse I have heard of by eBay/PayPal was a case where
a local guitar store owner sold a rather expensive, $4,000 + guitar to
someone in England. He got paid, then a few days later, he got an email
from eBay saying that the buyer had reported the item as fake and destroyed
it. They took the money back out of his bank account and wouldn't listen to
anything he had to say. Yes, there are unscrupulous buyers too.
Oh, I ordered one of those $9.50 GPSDOs too. I doubt I will ever see it. I
am not too optimistic about getting my money back either. We'll see.
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ewkehren via time-nuts
2018-04-11 14:16:17 UTC
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We use Excell nice to make plots and when needed add calculations File is to large for time nuts contact me direct and I will send you an exampleBert Kehren


Sent from my Galaxy Tab® A
-------- Original message --------From: CORNACCHIA via time-nuts <time-***@febo.com> Date: 4/10/18 2:35 PM (GMT-05:00) To: ewkehren via time-nuts <time-***@febo.com> Subject: Re: [time-nuts] Dual GPSDO - any advantage?
Bert may I ask how you created the charts (what software are you using).Thank You
    On Tuesday, April 10, 2018, 9:04:58 a.m. EDT, ewkehren via time-nuts <time-***@febo.com> wrote: 

Looking at the pictures it is the same unit I bought. It is not dual oven bit trimble works with LH right now shows tracking 10 satelites.Attached  is data that made  me buy a second one for Jürg for $ 129  and one more for me for $9.50.What you see is highly filtered data to see long time changes to better understand if analog filtering os possible. Planning on using Wenzel 600 sec. Filter maybe up to 2000 seconds. Board is ready for order.Top plot is my data against my Cs 5061B bottom is original Tbolt against his FTS  Cs. We use 53132 counters.I think  the new one lends it self better for filtering looking at both  with my Tracor, Trimble uses a  much shorter time constant and no short 1E-10 changes you see on our standard units.Will keep you posted         Bert Kehren

Sent from my Galaxy Tab® A
-------- Original message --------From: Tim Shoppa <***@gmail.com> Date: 4/10/18  6:46 AM  (GMT-05:00) To: Discussion of precise time and frequency measurement <time-***@febo.com> Subject: Re: [time-nuts] Dual GPSDO - any advantage?
Most of the Chinese cheapo units have been frequency, not phase locked.

It would be great if you could put the GPSDO outputs into a 2 Channel scope and eyeball them for a while to see if they appear in phase (say plus-minus 20ns) over a few hours.

Tim N3QE

> On Apr 10, 2018, at 1:43 AM, donald collie <***@gmail.com> wrote:
>
> I`ve just bought two GPSDO`s from China @ US$9-50 each [This is not an
> error!] They are stated as being new, and use a Trimball dual oven OCXO. I
> plan to run these in parallel [2 antennas, 2 feedlines, and 2 GPSDO`s] It`s
> been said that a man with two watches is never happy - unless, of course,
> they agree with each other ;-). Being identical the outputs should be
> coherent, unless one becomes faulty [one advantage of having two - any
> discrepancy and you know something must be wrong]], but is there some
> crafty way I can squeeze a little more "accuracy" out of two than if I only
> used one?
> TIA for your comments............................................Donald
> Brett Collie ZL4GX
>
> PS : I have no connection to the eBay seller. The US$9-50 seems to include
> a basic puck antenna, long downlead, and 4 interseries adaptors
> _______________________________________________
> time-nuts mailing list -- time-***@febo.com
> To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
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