Re: [time-nuts] Using a common power supply among few time standards

[Taka Kamiya via time-nuts]

I recall S-100 scheme had an issue of per-board regulator failing short and 
dumping 8V into bus killing rest of the system
I am thinking of making use of 28V (aircraft power supply?) regulated power 
supply, and have local linear regulator to created needed voltages.  One 
concern is, should I need large amount of 5V then loss will be tremendous.  I 
just came across an article that discussed magnetic field sensitivity of 
LPRO-101.  The author ended up relocating the transformer off-board.  (in a 
different case)  A very timely information as this is what I am actually 
working on.
Further comment will be appreciatedTakaTime-nut in training
--- 
(Mr.) Taka Kamiya
KB4EMF / ex JF2DKG
 

On Thursday, February 6, 2020, 6:51:38 PM EST, jimlux 
 wrote:  
 
 On 2/6/20 3:14 PM, Will Kimber wrote:
> Hi,
> 
> Usual (best?) is supply slight over voltage and use LDO/RC filtering in
> each unit as Bob suggested. But that would require either supplying
> 24v/12v/5v/-12v (with some margin 10%?) or converting some single supply
> of 24v or 48v  in each unit to required voltages at each piece of
> equipment.  The later requires switching supplies to get all voltages.


Well that was the strategy used on S-100 boards. Bulk 8V unregulated 
supply regulated down to 5V on the board.



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Re: [time-nuts] eLORAN to turn on next week for a test

[paul swed]

Well the government has funded 2 tests. So they are looking. But we will
end up with what makes someone the most money. The alternative seems to be
the Iridium satellite constellation. That way we have 2 different satellite
based solutions. H I don't see any problem with that at all.
Korea is indeed using real eLoran for PNT and actual navigation. Its still
in development but they see the need for an alternate solution to things in
the sky they don't control.
But off the soap box I have a cable to repair and preamp to check. The
Loran stuff hasn't been on since 2017 even though I have simulator and test
set. Time to bring that up from the basement. :-)
Regards
Paul

On Fri, Feb 7, 2020 at 8:39 PM Scott McGrath  wrote:

> I hope we finally light up eLoran and soon not only is it needed for time
> transfer.   As a pilot there have been way too many GPS outages and the
> ADS-B peer to peer system is totally dependent upon precision positioning
> signals from GPS.
>
> It’s unsettling to be doing a GPS approach only to be halfway into it and
> see ‘GPS Signal Lost’ - system restart.   Now you need to go around and
> shoot an ILS approach or visual if conditions allow.
>
> Of course most of the GPS outages are csused by truck drivers using GPS
> jammers.   But the why actually makes no difference GPS is gone and you are
> on your own.
>
> >
> > On Feb 7, 2020, at 5:57 PM, paul swed  wrote:
> >
>
> Hello fellow time-nuts. Just found out eLORAN will be on next week or so.
> Bringing Wildwood back on air the week of February 17th and then again the
> week of March 16th for a demonstration of UTC time synchronization. We’ll
> be broadcasting as 8970M and 8970X from Wildwood during those times.
> So if you still have gear and want to warm it up for checking frequency
> here is your chance.
> I already know I need to replace a 20' section of a 164' line of RG6 from a
> squirrel attack. Just replaced 140' of a 174' line due to the same for
> WWVB.
> Fortunately thats quite easy to do. Wonder if the pre-amps still good?
> Regards
> Paul
> WB8TSL
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Re: [time-nuts] eLORAN to turn on next week for a test

[Scott McGrath]

I hope we finally light up eLoran and soon not only is it needed for time 
transfer.   As a pilot there have been way too many GPS outages and the ADS-B 
peer to peer system is totally dependent upon precision positioning signals 
from GPS.

It’s unsettling to be doing a GPS approach only to be halfway into it and see 
‘GPS Signal Lost’ - system restart.   Now you need to go around and shoot an 
ILS approach or visual if conditions allow.

Of course most of the GPS outages are csused by truck drivers using GPS 
jammers.   But the why actually makes no difference GPS is gone and you are on 
your own.

> 
> On Feb 7, 2020, at 5:57 PM, paul swed  wrote:
> 

Hello fellow time-nuts. Just found out eLORAN will be on next week or so.
Bringing Wildwood back on air the week of February 17th and then again the
week of March 16th for a demonstration of UTC time synchronization. We’ll
be broadcasting as 8970M and 8970X from Wildwood during those times.
So if you still have gear and want to warm it up for checking frequency
here is your chance.
I already know I need to replace a 20' section of a 164' line of RG6 from a
squirrel attack. Just replaced 140' of a 174' line due to the same for WWVB.
Fortunately thats quite easy to do. Wonder if the pre-amps still good?
Regards
Paul
WB8TSL
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Re: [time-nuts] Experiments in NTP performance (Watson Ladd)

[Chris Quayle]

On 02/07/20 17:00, time-nuts-requ...@lists.febo.com wrote:

Experiments in NTP performance (Watson Ladd)


Hi,

I may have something to contribute to this, Built an
experimental system last year. Two or three surplus spares or repair
grade and refurbished time servers on a separate subnet, interrogated
by a Mini ITx PC box  running FreeBSD / ntpd. 1 PPS support via
the serial port dcd line. Registered with ntp.org, but not online
yet as still confirming system is rock solid. On a ups and has been
running now for months. Typical output from ntpq -p is:

root@ntp-host:/etc # ntpq -p
 remote   refid st t when poll reach   delay   offset  jitter
=
oPPS(0)  .PPS.   0 l28  3770.0000.001   0.001
*192.9.200.168   .GPS.   1 u   45   64  3770.189   -0.010   0.024
+192.9.200.169   .GPS.   1 u   19   64  3770.378   -0.012   0.037
-ntp0.uk.uu.net  .GPS.   1 u   42   64  377   16.9400.352   0.129

Two local sources and one external, for a sanity check...

Regards,

Chris



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[time-nuts] eLORAN to turn on next week for a test

[paul swed]

Hello fellow time-nuts. Just found out eLORAN will be on next week or so.
Bringing Wildwood back on air the week of February 17th and then again the
week of March 16th for a demonstration of UTC time synchronization. We’ll
be broadcasting as 8970M and 8970X from Wildwood during those times.
So if you still have gear and want to warm it up for checking frequency
here is your chance.
I already know I need to replace a 20' section of a 164' line of RG6 from a
squirrel attack. Just replaced 140' of a 174' line due to the same for WWVB.
Fortunately thats quite easy to do. Wonder if the pre-amps still good?
Regards
Paul
WB8TSL
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[time-nuts] Single PS possibility

[Perry Sandeen via time-nuts]

Learned gentlemen,
While the idea of a single supply for all devices is attractive, one faces the 
risk of having everything going down with a single failure.
Perhaps using multiple boost-buck SRPS's from a large battery supply might 
mitigate that risk. The vendor *Bang Good* seems to have a good reputation and 
the spec's listed seem to be very good.  The output voltages are variable so it 
could allow a final LDR to be on each device. The prices seem reasonable but 
constant current output listed may require an additional cooling fan.
Just FFT.
Regards,
Perrier
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[time-nuts] Fluke 164H counter question - Thanks!!!

[Tom Knox]

Hi Time-Nut;
I am sure someone has asked before, and I know the question will be asked in 
the future. Does anyone know how to enter the calibration menu on a Fluke 164H 
Multi-Function Counter? Does it require a code? I know the Scopemeters from 
this generation 9/99/105 series use a external 12 volts applied to the two pins 
in the battery compartment. Cannot seem to find a cal and service manual.
If you are unfamiliar with these, it is a really nice counter, they have 
amazing performance for a handheld.
Below is a link for a data sheet if you are interested:
https://www.used-line.com/Specs_URL/85/85.pdf
Fluke 164 - Used-Line.com
Accurate Phase Measurements Figures 3a and 3b show how a Multi-Function Counter 
performs, where by contrast both a Phasemeter and a scope or DVM would be 
required.
www.used-line.com

Thanks!!

Tom Knox

303-554-0307

act...@hotmail.com

"Peace is not the absence of violence, but the presence of Justice" Both MLK 
and Albert Einstein
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Re: [time-nuts] time-nuts Digest, Vol 187, Issue 9 Fake new LPRO 101 Rb's on Ebay

[Andre]

Its possible. Incidentally some of the "old" units have issues but can be fixed 
as others have found.
Still on the hunt for a Rb lamp with or without the casing, as I can probably 
make use of it even if low
voltage as a magnetic sensor or other high tech projects even if no good for a 
clock.
It would help if the metal lamp casing was physically intact but with all the 
outer bits removed as I probably
don't need this due to having a lot of other parts incl the expensive double 
oven oscillator.
Would also make one nerdy case light with an IR filter added.

-A


From: time-nuts  on behalf of 
time-nuts-requ...@lists.febo.com  listed as new may be new old stock, i.e. could they have been backup
> units in a box that never got put into service? That would suggest that
> they have full life available on the Rb lamp.
>




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Subject: Digest Footer

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End of time-nuts Digest, Vol 187, Issue 9
*


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