Re: [time-nuts] A new take on the all-hardware GPSDO concept

2016-09-26 Thread David 
Is there a schematic showing what you attempted?

I went back through the discussion thread and it was not real clear to
me which design you implemented.

On Mon, 26 Sep 2016 21:18:25 -0700, you wrote:

>...
>
>The results aren’t very good.
>
>With a short TC loop filter, the PLL does lock up, but obviously the jitter of 
>the Venus’ 10 MHz output comes through.
>
>With a longer TC, the PLL never locks - or at least if it does lock, it’s 
>locking significantly off frequency.
>
>That’s with a 10 µF cap and varied resistors between 10k and 1M. The best I 
>got was at 200k - a TC of 2s. That resulted in this video. Unlike other videos 
>I’ve made comparing two GPSDOs, this one is not a time-lapse. The reference is 
>an OH300 based GPSDO.
>
>https://www.youtube.com/watch?v=hiHRp0dCJ64 
>
>
>A time constant of 10s (1M resistor) just doesn’t work at all.
>
>But the real nail in the coffin here is that the price of the PLL chip is 
>still more expensive than the microcontroller and all of the components it 
>replaces.
>
>...
___
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.

Re: [time-nuts] A new take on the all-hardware GPSDO concept

2016-09-26 Thread Nick Sayer via time-nuts 
At the risk of inviting everyone to say “I told you so,” I’ll report here my 
experimental results from trying this concept out.

Since there was a great deal of doubt about the outcome, I hedged my bet a bit 
and designed for the DOT050V rather than the OH300. If it worked out for the 
TCXO, then I could try with the more expensive one.

The results aren’t very good.

With a short TC loop filter, the PLL does lock up, but obviously the jitter of 
the Venus’ 10 MHz output comes through.

With a longer TC, the PLL never locks - or at least if it does lock, it’s 
locking significantly off frequency.

That’s with a 10 µF cap and varied resistors between 10k and 1M. The best I got 
was at 200k - a TC of 2s. That resulted in this video. Unlike other videos I’ve 
made comparing two GPSDOs, this one is not a time-lapse. The reference is an 
OH300 based GPSDO.

https://www.youtube.com/watch?v=hiHRp0dCJ64 


A time constant of 10s (1M resistor) just doesn’t work at all.

But the real nail in the coffin here is that the price of the PLL chip is still 
more expensive than the microcontroller and all of the components it replaces.

In the end, I’m glad I tried, but I don’t think I’m going to invest any more 
time in the design. I could try configuring the venus for a 10 kHz output and 
see if it’s better able to phase lock with a divided TCXO output, but I don’t 
think I have any reason to believe that would be more likely to succeed.
___
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.

Re: [time-nuts] A new take on the all-hardware GPSDO concept

2016-09-26 Thread Nick Sayer via time-nuts 

> On Sep 16, 2016, at 1:13 PM, Lars Walenius  wrote:
> 
> 
> 
> My experience with the Venus838-T is only 2 weeks but disappointing. This can 
> also be guessed from the datasheet ADEV curve, that I guess is sawtooth 
> corrected values as it starts at 3E-9 at 1s, but is only 1E-11 at 1000s a 
> factor 10 worse than I get with the LEA-6T with the same antenna and setup. 
> If anyone have ADEV-MDEV curves to share I would be glad to see what can be 
> achieved with the venus838-T. My conclusion is also that sawtooth correction 
> is useless on my 838-T.

Are you talking about the PPS output or the frequency output (10 MHz by 
default)?

I haven’t attempted to get ADEV plots of the PPS output mainly because I’m not 
sure the best experimental setup. 

I could (try to) capture time differences between the PPS output of a 
thunderbolt and the PPS output of the Venus, but would taking the ADEV of that 
give correct results?

> 
> Lars
> 
> 
>> Nick wrote:
> 
>> Jim Miller's 10 kHz GPSDO that’s been referenced here has either solved this 
>> problem, or the 10 kHz output of the >Jupiter is substantially better than 
>> the Venus’ 10 MHz output, or the design doesn’t give the results time-nuts 
>> expect >from a GPSDO. Which of those applies?
> 
> 
> ___
> time-nuts mailing list -- time-nuts@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-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.

Re: [time-nuts] Inside of FT1200-100

2016-09-26 Thread Chuck Harris 
Back when I was going to work on mine, I was thinking of
prying the rubber away from the aluminum oven with something
like a feeler gauge, but also using some naptha (lighter fluid)
to help release any adhesive...  I didn't get around to doing
it, but that was the way I was going to progress.

-Chuck Harris

Ed Palmer wrote:
> 
> 
> On 2016-09-26 10:00 AM, Christopher Hoover  wrote:
>>> >
>>> >You might be able to slide something like a feeler guage down between the
>>> >oven and the rubber blanket to break the oscillator free.  The oven on mine
>>> >is a plain metal cylinder.  This way, the rubber sheet should protect the
>>> >Dewar from your feeler guage.  On mine, the mounting bolts for the 2N3792
>>> >transistor both have ground lugs.  I think I see them on yours.  You could
>>> >hook something through the ground lugs and use that to pull the oscillator
>>> >out of the rubber sheet and then remove the sheet later.
>>> >
>> Thanks Ed,
>>
>> I think the rubber sheet on mine is against metal.  I haven't yet seen the
>> glass dewar.
>>
>> The adhesion is huge.
>>
>> Do you know if the holes opposite the 2N3792 are threaded?   If they are, I
>> might try running the screws out and using those holes with longer screws
>> as my pull points.I can't pull on the lugs hard enough -- I've tried.
>>
>> -christopher.
>> 73 de AI6KG
> 
> Yes, you have seen the Dewar.  The silvery ring that's outside the rubber is 
> the top
> of the Dewar.  What you have to do is unstick and unfold the rubber starting 
> from the
> open area in the center.  Work your way outward.  The rubber is only 2 or 3 mm
> thick.  Once you completely clear the rubber out of the way, you'll see the 
> edge of
> the oven.  The TO-3 transistor is mounted on top of the oven assembly.  Once 
> you can
> see the edge, you have to slide something like a long feeler gauge down along 
> the
> edge of the oven to break it free from the rubber.  Work your way all around 
> the
> oven.  It's about 85 mm long.  It'll still be stuck on the bottom, but you 
> might be
> able to pull it free.
> 
> When I took mine apart, I ended up tearing off all the rubber at the top and 
> then
> cutting out that ring of hard foam to get at the Dewar so I could smash it 
> more.  I'm
> guessing you'd rather not do that! :)  But sacrificing the rubber on the top 
> might be
> okay, if you have to.
> 
> Sorry, but I don't know if the mounting holes for the transistor are threaded 
> or
> not.  In any case, since the oven and Dewar are bonded to the rubber, you're 
> pulling
> on the Dewar when you pull on the oven.  Not a good plan until you break the 
> oven
> free from the rubber.  Those Dewars are built in a rather fragile manner.  
> Your
> typical home Thermos is much more robust.
> 
> Ed
> 
> ___
> time-nuts mailing list -- time-nuts@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-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.

[time-nuts] FS: Prologix GPIB

2016-09-26 Thread Joseph Gray 
One like new Prologix GPIB-USB controller $100 plus shipping/insurance.

One like new Prologix GPIB-ETHERNET controller $150 plus shipping/insurance.

Joe Gray
W5JG
___
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.

[time-nuts] FS: Lucent GPSDO

2016-09-26 Thread Joseph Gray 
The new-in-box Lucent/Agilent  REF-0/REF-1 units that were selling on
ebay last year. I have been running this GPSDO ever since I bought it.
Includes a Meanwell 24 VDC power supply. I will also include a spare
REF-0 unit.

$200 OBO plus shipping/insurance.

More info: http://www.prc68.com/I/KS-24361.html

Joe Gray
W5JG
___
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.

Re: [time-nuts] Inside of FT1200-100

2016-09-26 Thread Ed Palmer 



On 2016-09-26 10:00 AM, Christopher Hoover  wrote:

>
>You might be able to slide something like a feeler guage down between the
>oven and the rubber blanket to break the oscillator free.  The oven on mine
>is a plain metal cylinder.  This way, the rubber sheet should protect the
>Dewar from your feeler guage.  On mine, the mounting bolts for the 2N3792
>transistor both have ground lugs.  I think I see them on yours.  You could
>hook something through the ground lugs and use that to pull the oscillator
>out of the rubber sheet and then remove the sheet later.
>

Thanks Ed,

I think the rubber sheet on mine is against metal.  I haven't yet seen the
glass dewar.

The adhesion is huge.

Do you know if the holes opposite the 2N3792 are threaded?   If they are, I
might try running the screws out and using those holes with longer screws
as my pull points.I can't pull on the lugs hard enough -- I've tried.

-christopher.
73 de AI6KG


Yes, you have seen the Dewar.  The silvery ring that's outside the 
rubber is the top of the Dewar.  What you have to do is unstick and 
unfold the rubber starting from the open area in the center.  Work your 
way outward.  The rubber is only 2 or 3 mm thick.  Once you completely 
clear the rubber out of the way, you'll see the edge of the oven.  The 
TO-3 transistor is mounted on top of the oven assembly.  Once you can 
see the edge, you have to slide something like a long feeler gauge down 
along the edge of the oven to break it free from the rubber.  Work your 
way all around the oven.  It's about 85 mm long.  It'll still be stuck 
on the bottom, but you might be able to pull it free.


When I took mine apart, I ended up tearing off all the rubber at the top 
and then cutting out that ring of hard foam to get at the Dewar so I 
could smash it more.  I'm guessing you'd rather not do that! :)  But 
sacrificing the rubber on the top might be okay, if you have to.


Sorry, but I don't know if the mounting holes for the transistor are 
threaded or not.  In any case, since the oven and Dewar are bonded to 
the rubber, you're pulling on the Dewar when you pull on the oven.  Not 
a good plan until you break the oven free from the rubber.  Those Dewars 
are built in a rather fragile manner.  Your typical home Thermos is much 
more robust.


Ed

___
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.

Re: [time-nuts] HP 5065A questions

2016-09-26 Thread Andy ZL3AG 

Thanks for the link to those handy documents, Luciano.

I have a serial 1420A that I plan on resurrecting once my lab is built.

Since seeing the capacitor warning, I checked it just now and sure enough, 1 
capacitor had vomited on the PCB, so I've removed it and cleaned the PCB ready 
for replacing all the suspect caps in the future.

My one has H89 option installed, and a extra output at 4.433MHZ = PAL TV 
subcarrier frequency. So I suspect that is what option H89 is.

Cheers,

Andy


On 26/09/2016, at 6:58 PM, timeok wrote:

> 
> I think that these pages can help you:
> http://www.timeok.it/wp-content/uploads/2015/09/First-aid-when-you-buy-an-hp5065A-v-1.2.pdf
> http://www.timeok.it/wp-content/uploads/2015/09/First-aid-II-when-you-buy-an-hp5065A-v-1.0.pdf
> 
>   Luciano
> 

___
time-nuts mailing list -- time-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.

Re: [time-nuts] HP 5065A questions

2016-09-26 Thread timeok 

I think that these pages can help you:
http://www.timeok.it/wp-content/uploads/2015/09/First-aid-when-you-buy-an-hp5065A-v-1.2.pdf
http://www.timeok.it/wp-content/uploads/2015/09/First-aid-II-when-you-buy-an-hp5065A-v-1.0.pdf

   Luciano

   From "time-nuts" time-nuts-boun...@febo.com
   To "time-nuts" time-nuts@febo.com
   Cc
   Date Sun, 25 Sep 2016 18:42:50 -0700
   Subject [time-nuts] HP 5065A questions
   Hello time-nuts,
   I have recently had the opportunity to play with an HP 5065A rubidium
   standard and have some questions. This unit has been powered down for
   quite a long time, it appears to be almost working. I can see both the
   137Hz and second harmonic signals but they seem very low.

   In the manual (the one from KO4BB.com) in section 3.9 (pg 3-1) there is a
   procedure to apply a 1A current through the TEC until the 2nd harmonic
   comes back (due to cell flooding).

   1. What the heck is rubidium cell flooding, and how does the TEC in the
   5065A fix this problem? None of the -many- rubidium oscillators that I
   have been inside before has a TEC, and I have never seen the subject
   addressed.
   The manual suggests that it may take several weeks at the 1A current to fix
   the problem (normal operation of the 5065A applies .7V across the TEC).

   2. When the coarse oscillator control is swept across 5Mhz (open loop) the
   137Hz ERROR signal swings about +/-8 on the meter. This seems low (and may
   be related to this flooding issue). Just wondering what others have seen
   on their units?

   3. On page 5-15 of the manual it says to adjust A7R29 for a 2nd harmonic
   voltage of 4V at A14(1). In the section on A14 on page 8-61 the table
   states that the normal A14(1) voltage is 8V. So which is it? Granted the
   2nd harmonic won't extinguish the CONTINUOUS light until it falls to less
   than about 1.1V.

   I'm also curious about the level of the 60MHz signal feeding the Rb cell.
   This unit has several volts of RF, which appears to be plenty, but just
   wondering if anyone has any baseline information.

   Also, any hints about the care and feeding of the HP 5065A would be
   welcome. Thanks in advance.

   Regards,
   Skip Withrow
   ___
   time-nuts mailing list -- time-nuts@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-nuts@febo.com
To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.