Re: [time-nuts] wwvb weak on east coast especially when the pre-amps under water.

[Attila Kinali]

On Mon, 14 May 2012 18:01:01 -0400
Joseph M Gwinn  wrote:

> Modern outdoor enclosures use a filter of some kind, but the underlying
> principle is the same.

I don't know what other types are around, but we use vents with
a gore-tex foil over them. Keeps water out but lets the case breath.
This prevents any pressure build up, which would then start to suck
watter in from the seal.

Unfortunately, i'm currently unable to find the maker or the type of
the vent... If anyone is interested in those, i'll can ask around.

Attila Kinali

-- 
The trouble with you, Shev, is you don't say anything until you've saved
up a whole truckload of damned heavy brick arguments and then you dump
them all out and never look at the bleeding body mangled beneath the heap
-- Tirin, The Dispossessed, U. Le Guin

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Re: [time-nuts] Trimble Resolution-T SMT caught behaving badly

[David J Taylor]

I am planning on making a simple NTP server using the Resolution SMT as 
the PPS input and a Rb oscillator (or any other 10MHz clock) to clock 
the CPU on the computer. If people are interested in a friendly 
interface board to the device let me know. My initial interface board 
design puts the PPS on the Carrier Detect line at RS-232 levels as is 
typical for this sort of thing, but USB is also very easy to do.


[Off-list]

Michael, yes, I would be interested in two boards.  Likely I would be 
feeding the unit from +5V from a USB cable, so an on-board +3.3V regulator 
would be helpful, as would a connection to the non-standard header.  I 
don't have SMT soldering capabilities, so either a standard 0.1-inch DIL 
style board, or a completed unit would be best.  I would be prepared to 
pay up to around US $20 per board.  Serial output from an RS-232 level 
port would suit, although I can see scope for a USB-emulated serial as 
well.  That sounds like a major complication for the board, though.


Cheers,
David
--
SatSignal software - quality software written to your requirements
Web:  http://www.satsignal.eu
Email:  david-tay...@blueyonder.co.uk 



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Re: [time-nuts] Conformal Coating

[Lee Mushel]

Be careful!   You have now introduced a "label" into the discussion that 
might trigger some vendor into thinking that you are looking for a UV Cured 
coating.   And those things can be something you don't want to mess with.


Back in the 70's when those coatings first appeared no one bothered to take 
note that they are very chemically reactive---they have to be since UV light 
is not a particularly agressive curing agent and to compensate for that UV 
"cured"  (not simply something that fluoresces)materials  tend to be stuff 
that you don't want to come in contact with.   I can show you some places on 
my left hand that break into open sores today, some 35 years later. 
Today, no one doubts that they are carcinogens.


Lee Mushel
- Original Message - 
From: "Michael Blazer" 

To: 
Sent: Monday, May 14, 2012 8:51 PM
Subject: Re: [time-nuts] Conformal Coating


>>
The Humiseal product also has a UV indicator in it that glows blue under 
a

black light so you can check coverage.






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Re: [time-nuts] Trimble Resolution-T SMT caught behaving badly

[Michael Tharp]

On 05/14/2012 09:11 PM, Mark Sims wrote:


Attached is a Lady Heather screen dump of a Trimble Resolution-SMT timing 
receiver behaving badly.  The first quarter of the plot the unit was tracking 
all sats above 0 degrees/0 dBc.  The next quarter the masks were set to 30 
degrees/30 dBc.   Then at the half way point,  something strange happened...

The green plot is the sawtooth correction value.  It should be +/- 15 nS,  but 
was only running +10/-13 ns.  At the half way point the sawtooth started 
spiking down to -38.00 ns...  obviously some internal clipping limit.   It 
ran this way for a day,  then I reset the unit and all has been well since.

The purple plot is the unit's "local clock bias".  It is reported like the 
Tbolt's PPS value.It is a sawtooth that covers a 1000 usec (almost) range. It repeats 
over a 28 minute period.

The white plot is the "clock bias rate".  In comes in like the Tbolt OSC value. 
 Yellow is temperature.   Note how well those two plots track each other.   Suggests that 
some active temperature control might be useful.

One nice thing about the Resolution receiver is that it returns tracking info 
for all sats,  even those below the elevation/signal masks.  This lets you 
build a signal level map even when you have elevation and signal level masks 
set.   Also note the high signal levels.  On a Tbolt,  I never see signals past 
green... the receiver is 6 db more sensitive.


Thanks for your notes on this device. I just got mine in the mail today, 
along with a 40dB antenna. Unfortunately I don't yet have the cable to 
connect the two, so right now it's running from a short length of bare 
wire, indoors, and as such can't really get a decent fix :-) It has 
managed to lock onto 4 satellites though, so it seems to work well 
enough to give me something to look at until I get materials to make a 
cable.


I am planning on making a simple NTP server using the Resolution SMT as 
the PPS input and a Rb oscillator (or any other 10MHz clock) to clock 
the CPU on the computer. If people are interested in a friendly 
interface board to the device let me know. My initial interface board 
design puts the PPS on the Carrier Detect line at RS-232 levels as is 
typical for this sort of thing, but USB is also very easy to do.


Regarding the default protocol being TEP, I easily managed to 
reconfigure it for TSIP using GPS Studio. The current version (1.08.0) 
supports TEP, and using Tools -> Configurator you can reprogram the 
Resolution SMT to use TSIP or NMEA by default. There are several other 
parameters that can be reprogrammed per the manual, including the width 
of the PPS.


Cheers,
-- m. tharp

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Re: [time-nuts] Trimble Resolution-T SMT caught behaving badly

[Hal Murray]

hol...@hotmail.com said:
> Then at the half way point, something strange happened...

I've seen quite a few GPS receivers do strange things.  My straw man is 
software bugs under poor signal conditions that don't get tested much.

Another possibility would be a glitch on the power rail(s).  It's really hard 
to get power-up reset and brownout reset right.


-- 
These are my opinions.  I hate spam.




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Re: [time-nuts] Conformal Coating

[Michael Blazer]

The Humiseal and Chemtronics Acrylic both meet the Mil Spec 'AR' rating. 
(I've had to track down this document trail.)  I believe the MG 
Chemicals also meets the same spec.  The MG and Chemtronics are readily 
available at most local electronic stores, Newark, Mouser and other 
distributors.


Mike

On 5/14/2012 8:13 PM, Sam Reaves wrote:

For conformal coating I recommend Humiseal Acrylic 1B73 in aerosol. You can
also get it in brush form. I believe that Chemtronics used to offer acrylic
coating as well, maybe even re-packaging the Humiseal product. I don't know
if there is a source for small quantities of Humiseal but it is a fine
product.

I have also used Krylon clear acrylic that you can get at Wall-Mart in a
pinch. The acrylic coatings I have found are better for HiZ circuits that
have requirements for low-leakage. Consult the can for solvents and make
sure that what you are coating are compatible with Toluene, Ketones,
Acetone, etc. be careful around connectors as the coating will wick into
connectors as the 1B73 is a fairly low viscosity. You can also get Humiseal
formulations 1B38 and 1B66 which are also Acrylics but are brush on and
require a one gallon minimum purchase. The shipping cost for a gallon is
almost as much as the product due to the requirement that it be shipped as
a hazardous material (flameable). The acrylics can be dissolved with MEK or
any of the solvents I have listed above. You can remove a small amount with
a Q-Tip.

The Humiseal product also has a UV indicator in it that glows blue under a
black light so you can check coverage.

I have tested Humiseal Acrylic on probably 1000+ PCB's and it has yet to
fail me. It is also easy to rework and re-coat after repairs.

You can also get polyurethane coatings but I do not recommend them since
they are more difficult you use, not as easy to remove
and have better performance for HiZ and RF circuits.

Good luck and let us know how you make out.

Sam
W3OHM

http://www.hmcelectronics.com/product/Chemtronics/CTAR12




On Mon, May 14, 2012 at 7:31 PM,  wrote:


Send time-nuts mailing list submissions to
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Today's Topics:

   1. Re: Why are 1PPS signals so skinny? (Jim Hickstein)
   2. Re: Why are 1PPS signals so skinny? (Azelio Boriani)
   3. Re: wwvb weak on east coast especially when the pre-amps
  under wa... (Michael Blazer)
   4. Re: wwvb weak on east coast especially when the pre-amps
  under wa... (Azelio Boriani)
   5. Re: Why are 1PPS signals so skinny? (Michael Blazer)
   6. Re: Why are 1PPS signals so skinny? (Bob Camp)
   7. Re: wwvb weak on east coast especially when thepre-amps   under
  wa... (Alan Melia)


--

Message: 1
Date: Mon, 14 May 2012 18:18:20 -0500
From: Jim Hickstein
To: time-nuts@febo.com
Subject: Re: [time-nuts] Why are 1PPS signals so skinny?
Message-ID:<4fb192bc.4060...@jxh.com>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed

On 2012/05/14 18:02, time-nuts-requ...@febo.com wrote:

https://assist.daps.dla.mil/quicksearch/  is the search site for

military standards.

Hmm.  Doesn't find MIL-TGDBP-41.  I got this from my (now late) great
uncle, Bob
Sedgwick -- who was to hydraulics what I am to computers, only he has a
number
of patents.

Some smart-aleck at Wright Field, as it then was, put this on a drawing,
and it
went without comment for quite a while until someone tried to look it up.
  This
escalated to a bird colonel, who then tracked down the miscreant.

It stands for Make It Like The G-D Blueprint For Once.



--

Message: 2
Date: Tue, 15 May 2012 01:21:26 +0200
From: Azelio Boriani
To: Discussion of precise time and frequency measurement

Subject: Re: [time-nuts] Why are 1PPS signals so skinny?
Message-ID:
  wrote:


On 2012/05/14 18:02, time-nuts-requ...@febo.com wrote:


https://assist.daps.dla.mil/quicksearch/  is the search site for
military standards.


Hmm.  Doesn't find MIL-TGDBP-41.  I got this from my (now late) great
uncle, Bob Sedgwick -- who was to hydraulics what I am to computers, only
he has a number of patents.

Some smart-aleck at Wright Field, as it then was, put this on a drawing,
and it went without comment for quite a while until someone tried to look
it up.  This escalated to a bird colonel, who then tracked down the
miscreant.

It stands for Make It Like The G-D Blueprint For Once.


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Re: [time-nuts] wwvb weak on east coast especially when the pre-amps under wa...

[paul swed]

I speculate that water runs off.
But that said the preamp did run 4 years and I didn't really do anything
special.
In fact the preamps cleaned up and ready to be remounted tomorrow. But
first I have to see what may have let the moisture in. At least was it
something large that needs to be plugged etc.
Thanks everyone
Regards
Paul.

On Mon, May 14, 2012 at 10:39 PM, Hal Murray wrote:

>
> k3...@aol.com said:
> > If you can keep the boards in a vertical mount position, and they have
> been
> > sprayed with a conformal coating, the heat from the components and the
> > coating will keep any moisture from forming on the boards in a vertical
> > position.  We do this in several products we supply to the military.
>
> Does this help significantly for an antenna preamp that doesn't dissipate
> much power?
>
> How much power does a board have to dissipate to keep dry?  I assume it
> depends upon the size of the board, but I doubt if it's linear.
>
> What's magic about vertical for keeping dry?  I'd expect a vertical board
> to
> have better air flow and hence better cooling, but does that keep it dryer?
>
>
> --
> These are my opinions.  I hate spam.
>
>
>
>
> ___
> time-nuts mailing list -- time-nuts@febo.com
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Re: [time-nuts] wwvb weak on east coast especially when the pre-amps under wa...

[Hal Murray]

k3...@aol.com said:
> If you can keep the boards in a vertical mount position, and they have been 
> sprayed with a conformal coating, the heat from the components and the
> coating will keep any moisture from forming on the boards in a vertical
> position.  We do this in several products we supply to the military.

Does this help significantly for an antenna preamp that doesn't dissipate 
much power?

How much power does a board have to dissipate to keep dry?  I assume it 
depends upon the size of the board, but I doubt if it's linear.
 
What's magic about vertical for keeping dry?  I'd expect a vertical board to 
have better air flow and hence better cooling, but does that keep it dryer?


-- 
These are my opinions.  I hate spam.




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Re: [time-nuts] Conformal Coating

[Tom Knox]

That sounds like what we use in the AeroSpace industry. I remember the UV dye. 
Thanks

Thomas Knox



> Date: Mon, 14 May 2012 21:13:55 -0400
> From: sam.rea...@gmail.com
> To: time-nuts@febo.com
> Subject: Re: [time-nuts] Conformal Coating
> 
> For conformal coating I recommend Humiseal Acrylic 1B73 in aerosol. You can
> also get it in brush form. I believe that Chemtronics used to offer acrylic
> coating as well, maybe even re-packaging the Humiseal product. I don't know
> if there is a source for small quantities of Humiseal but it is a fine
> product.
> 
> I have also used Krylon clear acrylic that you can get at Wall-Mart in a
> pinch. The acrylic coatings I have found are better for HiZ circuits that
> have requirements for low-leakage. Consult the can for solvents and make
> sure that what you are coating are compatible with Toluene, Ketones,
> Acetone, etc. be careful around connectors as the coating will wick into
> connectors as the 1B73 is a fairly low viscosity. You can also get Humiseal
> formulations 1B38 and 1B66 which are also Acrylics but are brush on and
> require a one gallon minimum purchase. The shipping cost for a gallon is
> almost as much as the product due to the requirement that it be shipped as
> a hazardous material (flameable). The acrylics can be dissolved with MEK or
> any of the solvents I have listed above. You can remove a small amount with
> a Q-Tip.
> 
> The Humiseal product also has a UV indicator in it that glows blue under a
> black light so you can check coverage.
> 
> I have tested Humiseal Acrylic on probably 1000+ PCB's and it has yet to
> fail me. It is also easy to rework and re-coat after repairs.
> 
> You can also get polyurethane coatings but I do not recommend them since
> they are more difficult you use, not as easy to remove
> and have better performance for HiZ and RF circuits.
> 
> Good luck and let us know how you make out.
> 
> Sam
> W3OHM
> 
> http://www.hmcelectronics.com/product/Chemtronics/CTAR12
> 
> 
> 
> 
> On Mon, May 14, 2012 at 7:31 PM,  wrote:
> 
> > Send time-nuts mailing list submissions to
> >time-nuts@febo.com
> >
> > To subscribe or unsubscribe via the World Wide Web, visit
> >https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> > or, via email, send a message with subject or body 'help' to
> >time-nuts-requ...@febo.com
> >
> > You can reach the person managing the list at
> >time-nuts-ow...@febo.com
> >
> > When replying, please edit your Subject line so it is more specific
> > than "Re: Contents of time-nuts digest..."
> >
> >
> > Today's Topics:
> >
> >   1. Re: Why are 1PPS signals so skinny? (Jim Hickstein)
> >   2. Re: Why are 1PPS signals so skinny? (Azelio Boriani)
> >   3. Re: wwvb weak on east coast especially when the pre-amps
> >  under wa... (Michael Blazer)
> >   4. Re: wwvb weak on east coast especially when the pre-amps
> >  under wa... (Azelio Boriani)
> >   5. Re: Why are 1PPS signals so skinny? (Michael Blazer)
> >   6. Re: Why are 1PPS signals so skinny? (Bob Camp)
> >   7. Re: wwvb weak on east coast especially when thepre-amps   under
> >  wa... (Alan Melia)
> >
> >
> > --
> >
> > Message: 1
> > Date: Mon, 14 May 2012 18:18:20 -0500
> > From: Jim Hickstein 
> > To: time-nuts@febo.com
> > Subject: Re: [time-nuts] Why are 1PPS signals so skinny?
> > Message-ID: <4fb192bc.4060...@jxh.com>
> > Content-Type: text/plain; charset=ISO-8859-1; format=flowed
> >
> > On 2012/05/14 18:02, time-nuts-requ...@febo.com wrote:
> > > https://assist.daps.dla.mil/quicksearch/  is the search site for
> > military standards.
> >
> > Hmm.  Doesn't find MIL-TGDBP-41.  I got this from my (now late) great
> > uncle, Bob
> > Sedgwick -- who was to hydraulics what I am to computers, only he has a
> > number
> > of patents.
> >
> > Some smart-aleck at Wright Field, as it then was, put this on a drawing,
> > and it
> > went without comment for quite a while until someone tried to look it up.
> >  This
> > escalated to a bird colonel, who then tracked down the miscreant.
> >
> > It stands for Make It Like The G-D Blueprint For Once.
> >
> >
> >
> > --
> >
> > Message: 2
> > Date: Tue, 15 May 2012 01:21:26 +0200
> > From: Azelio Boriani 
> > To: Discussion of precise time and frequency measurement
> >
> > Subject: Re: [time-nuts] Why are 1PPS signals so skinny?
> > Message-ID:
> > > >
> > Content-Type: text/plain; charset=ISO-8859-1
> >
> > Maybe the correct number is MIL-STD-188-115?
> >
> > On Tue, May 15, 2012 at 1:18 AM, Jim Hickstein  wrote:
> >
> > > On 2012/05/14 18:02, time-nuts-requ...@febo.com wrote:
> > >
> > >> https://assist.daps.dla.mil/quicksearch/  is the search site for
> > >> military standards.
> > >>
> > >
> > > Hmm.  Doesn't find MIL-TGDBP-41.  I got this from my (now late) great
> > > uncle, Bob Sedgwick -- who was to hydraulics what I am to computers, only
> > > h

Re: [time-nuts] Why are 1PPS signals so skinny?

[Said Jackson]

These types of pulses should be routed as open-ended source-terminated 
reflected wave switched transmission lines. Power will only flow for 
nanoseconds as the pulse travels over the line. There won't be a drop of 50% of 
the voltage at the target and no large power spikes in the unit or requirements 
for proper impedance matching at the receiver side.

Some units like the thunderbolt look quite bad driving a 50 ohms transmission 
line, others that are designed with proper 50 ohms series impedance create a 
sharp nice signal.

Bye,
Said




Sent from my iPad

On May 14, 2012, at 17:21, "Tom Van Baak"  wrote:

> Mark,
> 
> I too once preferred 50% duty cycle 1 Hz signals because they seemed more 
> "natural". But one day during an experiment where I was comparing a large set 
> of clocks I noticed my lab's digital AC power meter was jumping by tens of 
> watts every second.
> 
> When a dozen DUT generate 1PPS along with as many REF pulses (via cascaded 
> pulse distribution amps) and then these all go to both inputs of a TIC and 
> there's also LED's on both TIC channels as well as the dist amps, the net 
> load is enormous. The last thing you want in a precision timing lab is to 
> load your AC line down exactly once a second. Remember 5V into 50R is 0.1 
> Amps. That was a modest amount of current in the 1950's, but massive overkill 
> today.
> 
> So that's why I now prefer short (e.g., 1 ms or 10 us) pulses.
> 
> /tvb
> 
> 
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Re: [time-nuts] wwvb weak on east coast especially when the pre-amps under wa...

[Tom Knox]

What type of coating do you recommend? What is the downside of coating all 
electronics?

Thomas Knox



> From: k3...@aol.com
> Date: Mon, 14 May 2012 21:16:15 -0400
> To: time-nuts@febo.com
> Subject: Re: [time-nuts] wwvb weak on east coast especially when the  
> pre-amps under wa...
> 
> If you can keep the boards in a vertical mount position, and they have been 
>  sprayed with a conformal coating, the heat from the components and the 
> coating  will keep any moisture from forming on the boards in a vertical 
> position.   We do this in several products we supply to the military.
>  
> Dr Joe Palsa k3wry
>  
>  
> In a message dated 5/14/2012 9:03:13 P.M. Eastern Daylight Time,  
> gandal...@aol.com writes:
> 
> The  other option of course is to pressurise the box with dry air to ensure 
>   
> a positive pressure differential, such that the net flow is always  
> outwards 
> at  all points, but it's probably easier just to provide a  drain hole:-)
> 
> However, whilst a drain hole will prevent the build up of  a lake inside 
> the 
> enclosure it still doesn't prevent condensation forming  on circuit boards, 
> and  powered circuit boards and condensation don't  really go well  
> together.
> 
> As per earlier comments, it's quite  difficult to keep any externally  
> mounted enclosure totally moisture  free, so it's much easier to accept the 
>  
> inevitable and allow for  it.
> 
> In a past life I designed quite a few circuit boards that   were required 
> to 
> be fitted in externally mounted vented enclosures, so  not  a great deal of 
> pressurisation there then:-), and I usually  specified that  both sides 
> should be sprayed with a plastic coating  following final test.
> 
> I can't remember now exactly what this stuff was  called, but it  was 
> readily available in the UK from both RS and  Farnell as an aerosol plastic 
>  spray 
> that provided a good barrier but  was a bit more flexible than the  usual 
> MOD 
> spec conformal  coatings.
> It melted easily under a soldering iron, albeit with a foul   pong:-), so 
> reworking was no problem, and resisted moisture  remarkably  well.
> 
> problem  solved:-)
> 
> Nigel
> GM8PZR
> 
> 
> 
> 
> 
> In a message dated  14/05/2012 23:10:30 GMT Daylight Time,  
> arnold.ti...@gmx.de  writes:
> 
> The only  solutions I think:
> Apply air pressure tight  boxes having a breathing hole  an the bottom,
> mount the
> box that no  rain and water can penetrate from  the top or sides. If the
> hole is  big enough,
> eg. 2mm, no pressure  difference is possible and no  pumping effect will
> occur.
> (If the hole is  too wide, small animals  may penetrate).
> Or,
> when using a pressure tight  box, it must be  stiff and sealed to
> withstand under all
> temperature  conditions  more then 1 bar/ 100 kPa. Do not forget that  all
> feed
> throughs  must be of real hermetic type, normal coaxial  connectors are
> not  tight!
> Don't route cables directly in, because no  cable braid or mesh  is   vapor
> tight.
> ___
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Re: [time-nuts] wwvb weak on east coast especially when thepre-amps under wa...

[lists]

I haven't read all this thread, but NEMA boxes hopefully have been mentioned. 


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Re: [time-nuts] wwvb weak on east coast especially when the pre-amps under wa...

[K3WRY]

If you can keep the boards in a vertical mount position, and they have been 
 sprayed with a conformal coating, the heat from the components and the 
coating  will keep any moisture from forming on the boards in a vertical 
position.   We do this in several products we supply to the military.
 
Dr Joe Palsa k3wry
 
 
In a message dated 5/14/2012 9:03:13 P.M. Eastern Daylight Time,  
gandal...@aol.com writes:

The  other option of course is to pressurise the box with dry air to ensure 
  
a positive pressure differential, such that the net flow is always  
outwards 
at  all points, but it's probably easier just to provide a  drain hole:-)

However, whilst a drain hole will prevent the build up of  a lake inside 
the 
enclosure it still doesn't prevent condensation forming  on circuit boards, 
and  powered circuit boards and condensation don't  really go well  
together.

As per earlier comments, it's quite  difficult to keep any externally  
mounted enclosure totally moisture  free, so it's much easier to accept the 
 
inevitable and allow for  it.

In a past life I designed quite a few circuit boards that   were required 
to 
be fitted in externally mounted vented enclosures, so  not  a great deal of 
pressurisation there then:-), and I usually  specified that  both sides 
should be sprayed with a plastic coating  following final test.

I can't remember now exactly what this stuff was  called, but it  was 
readily available in the UK from both RS and  Farnell as an aerosol plastic 
 spray 
that provided a good barrier but  was a bit more flexible than the  usual 
MOD 
spec conformal  coatings.
It melted easily under a soldering iron, albeit with a foul   pong:-), so 
reworking was no problem, and resisted moisture  remarkably  well.

problem  solved:-)

Nigel
GM8PZR





In a message dated  14/05/2012 23:10:30 GMT Daylight Time,  
arnold.ti...@gmx.de  writes:

The only  solutions I think:
Apply air pressure tight  boxes having a breathing hole  an the bottom,
mount the
box that no  rain and water can penetrate from  the top or sides. If the
hole is  big enough,
eg. 2mm, no pressure  difference is possible and no  pumping effect will
occur.
(If the hole is  too wide, small animals  may penetrate).
Or,
when using a pressure tight  box, it must be  stiff and sealed to
withstand under all
temperature  conditions  more then 1 bar/ 100 kPa. Do not forget that  all
feed
throughs  must be of real hermetic type, normal coaxial  connectors are
not  tight!
Don't route cables directly in, because no  cable braid or mesh  is   vapor
tight.
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Re: [time-nuts] Conformal Coating

[Sam Reaves]

For conformal coating I recommend Humiseal Acrylic 1B73 in aerosol. You can
also get it in brush form. I believe that Chemtronics used to offer acrylic
coating as well, maybe even re-packaging the Humiseal product. I don't know
if there is a source for small quantities of Humiseal but it is a fine
product.

I have also used Krylon clear acrylic that you can get at Wall-Mart in a
pinch. The acrylic coatings I have found are better for HiZ circuits that
have requirements for low-leakage. Consult the can for solvents and make
sure that what you are coating are compatible with Toluene, Ketones,
Acetone, etc. be careful around connectors as the coating will wick into
connectors as the 1B73 is a fairly low viscosity. You can also get Humiseal
formulations 1B38 and 1B66 which are also Acrylics but are brush on and
require a one gallon minimum purchase. The shipping cost for a gallon is
almost as much as the product due to the requirement that it be shipped as
a hazardous material (flameable). The acrylics can be dissolved with MEK or
any of the solvents I have listed above. You can remove a small amount with
a Q-Tip.

The Humiseal product also has a UV indicator in it that glows blue under a
black light so you can check coverage.

I have tested Humiseal Acrylic on probably 1000+ PCB's and it has yet to
fail me. It is also easy to rework and re-coat after repairs.

You can also get polyurethane coatings but I do not recommend them since
they are more difficult you use, not as easy to remove
and have better performance for HiZ and RF circuits.

Good luck and let us know how you make out.

Sam
W3OHM

http://www.hmcelectronics.com/product/Chemtronics/CTAR12




On Mon, May 14, 2012 at 7:31 PM,  wrote:

> Send time-nuts mailing list submissions to
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> than "Re: Contents of time-nuts digest..."
>
>
> Today's Topics:
>
>   1. Re: Why are 1PPS signals so skinny? (Jim Hickstein)
>   2. Re: Why are 1PPS signals so skinny? (Azelio Boriani)
>   3. Re: wwvb weak on east coast especially when the pre-amps
>  under wa... (Michael Blazer)
>   4. Re: wwvb weak on east coast especially when the pre-amps
>  under wa... (Azelio Boriani)
>   5. Re: Why are 1PPS signals so skinny? (Michael Blazer)
>   6. Re: Why are 1PPS signals so skinny? (Bob Camp)
>   7. Re: wwvb weak on east coast especially when thepre-amps   under
>  wa... (Alan Melia)
>
>
> --
>
> Message: 1
> Date: Mon, 14 May 2012 18:18:20 -0500
> From: Jim Hickstein 
> To: time-nuts@febo.com
> Subject: Re: [time-nuts] Why are 1PPS signals so skinny?
> Message-ID: <4fb192bc.4060...@jxh.com>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>
> On 2012/05/14 18:02, time-nuts-requ...@febo.com wrote:
> > https://assist.daps.dla.mil/quicksearch/  is the search site for
> military standards.
>
> Hmm.  Doesn't find MIL-TGDBP-41.  I got this from my (now late) great
> uncle, Bob
> Sedgwick -- who was to hydraulics what I am to computers, only he has a
> number
> of patents.
>
> Some smart-aleck at Wright Field, as it then was, put this on a drawing,
> and it
> went without comment for quite a while until someone tried to look it up.
>  This
> escalated to a bird colonel, who then tracked down the miscreant.
>
> It stands for Make It Like The G-D Blueprint For Once.
>
>
>
> --
>
> Message: 2
> Date: Tue, 15 May 2012 01:21:26 +0200
> From: Azelio Boriani 
> To: Discussion of precise time and frequency measurement
>
> Subject: Re: [time-nuts] Why are 1PPS signals so skinny?
> Message-ID:
> >
> Content-Type: text/plain; charset=ISO-8859-1
>
> Maybe the correct number is MIL-STD-188-115?
>
> On Tue, May 15, 2012 at 1:18 AM, Jim Hickstein  wrote:
>
> > On 2012/05/14 18:02, time-nuts-requ...@febo.com wrote:
> >
> >> https://assist.daps.dla.mil/quicksearch/  is the search site for
> >> military standards.
> >>
> >
> > Hmm.  Doesn't find MIL-TGDBP-41.  I got this from my (now late) great
> > uncle, Bob Sedgwick -- who was to hydraulics what I am to computers, only
> > he has a number of patents.
> >
> > Some smart-aleck at Wright Field, as it then was, put this on a drawing,
> > and it went without comment for quite a while until someone tried to look
> > it up.  This escalated to a bird colonel, who then tracked down the
> > miscreant.
> >
> > It stands for Make It Like The G-D Blueprint For Once.
> >
> >
> > ___
> > time-nuts mailing list -- time-nuts@febo.com
> > To unsubscribe, go to
> > https://www.febo.com/cg

[time-nuts] Why are 1PPS signals so skinny?

[Mark Sims]

Tom,

Send me your masers/cesiums and it'll save you the horrendous grief that those 
pesky pulsey signals are causing you...


I still like 50:50 duty cycles.  It makes das blinkenlights so much easier to 
see.
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Re: [time-nuts] Why are 1PPS signals so skinny?

[Bob Camp]

Hi

If you want to avoid a crazy power supply, you decouple the power to the output 
amplifier on the PPS driver. Nice big caps, droop a little during the pulse. 
Charge up while there's no pulse.

Bob

On May 14, 2012, at 8:44 PM, Mike S wrote:

> On 5/14/2012 8:21 PM, Tom Van Baak wrote:
>> one day during an experiment where I was
>> comparing a large set of clocks I noticed my lab's digital AC power
>> meter was jumping by tens of watts every second.
>> 
>> The last thing you want
>> in a precision timing lab is to load your AC line down exactly once a
>> second.
> 
> How does a short pulse help? It's still "tens of watts every second," but 
> instead of lasting 0.5 seconds, it lasts 0.5 seconds. Less power used 
> overall, but still the same sudden change on the second.
> 
> ___
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Re: [time-nuts] Why are 1PPS signals so skinny?

[Mike S]

On 5/14/2012 8:21 PM, Tom Van Baak wrote:

one day during an experiment where I was
comparing a large set of clocks I noticed my lab's digital AC power
meter was jumping by tens of watts every second.

The last thing you want
in a precision timing lab is to load your AC line down exactly once a
second.


How does a short pulse help? It's still "tens of watts every second," 
but instead of lasting 0.5 seconds, it lasts 0.5 seconds. Less power 
used overall, but still the same sudden change on the second.


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Re: [time-nuts] Why are 1PPS signals so skinny?

[Tom Van Baak]

Mark,

I too once preferred 50% duty cycle 1 Hz signals because they seemed more 
"natural". But one day during an experiment where I was comparing a large set 
of clocks I noticed my lab's digital AC power meter was jumping by tens of 
watts every second.

When a dozen DUT generate 1PPS along with as many REF pulses (via cascaded 
pulse distribution amps) and then these all go to both inputs of a TIC and 
there's also LED's on both TIC channels as well as the dist amps, the net load 
is enormous. The last thing you want in a precision timing lab is to load your 
AC line down exactly once a second. Remember 5V into 50R is 0.1 Amps. That was 
a modest amount of current in the 1950's, but massive overkill today.

So that's why I now prefer short (e.g., 1 ms or 10 us) pulses.

/tvb


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Re: [time-nuts] wwvb weak on east coast especially when thepre-amps under wa...

[J. Forster]

The military deals with this all the time.

Some equipment is housed in near hermetic, gasketed, metal enclosures with
bags of drying agent, like silica gel, or purpose built, screw in
dessicators, often with a humidity indicator. The HP 117A clock has one of
them on the front panel.

For larger volumes, like the "football" loop antennas used on WW II 
aircraft ADFs, the units were sealed with gaskets and had a 1/4" or 5/16"
robber tubing connected to a cartridge dessicator filled with silica gel
that was pink when damp, blue when dry. These antennas had a tidal volume
of a gallon or two and breathed a lot in going from sea level to 25,000 -
30,000 feet.

You can easily mahe a sealed enclosure from a cast aluminum box, sealed
with RTV.

-John

===



> Well almost Nigel, if you look at molecule mean velocities they are always
> able to diffuse down a concentration gradient (i.e from wet into dry)
> despite a small reverse presure gradient. It just takes longer under those
> conditions :-))which is often "enough"
>
> Alan G3NYK
> - Original Message -
> From: 
> To: 
> Sent: Tuesday, May 15, 2012 12:01 AM
> Subject: Re: [time-nuts] wwvb weak on east coast especially when
> thepre-amps
> under wa...
>
>
>> The other option of course is to pressurise the box with dry air to
>> ensure
>> a positive pressure differential, such that the net flow is always
> outwards
>> at  all points, but it's probably easier just to provide a drain hole:-)
>>
>> However, whilst a drain hole will prevent the build up of a lake inside
> the
>>  enclosure it still doesn't prevent condensation forming on circuit
> boards,
>> and  powered circuit boards and condensation don't really go well
> together.
>>
>> As per earlier comments, it's quite difficult to keep any externally
>> mounted enclosure totally moisture free, so it's much easier to accept
>> the
>> inevitable and allow for it.
>>
>> In a past life I designed quite a few circuit boards that  were required
> to
>> be fitted in externally mounted vented enclosures, so not  a great deal
>> of
>> pressurisation there then:-), and I usually specified that  both sides
>> should be sprayed with a plastic coating following final test.
>>
>> I can't remember now exactly what this stuff was called, but it  was
>> readily available in the UK from both RS and Farnell as an aerosol
>> plastic
> spray
>> that provided a good barrier but was a bit more flexible than the  usual
> MOD
>> spec conformal coatings.
>> It melted easily under a soldering iron, albeit with a foul  pong:-), so
>> reworking was no problem, and resisted moisture remarkably  well.
>>
>> problem solved:-)
>>
>> Nigel
>> GM8PZR
>>
>>
>>
>>
>>
>> In a message dated 14/05/2012 23:10:30 GMT Daylight Time,
>> arnold.ti...@gmx.de writes:
>>
>> The only  solutions I think:
>> Apply air pressure tight boxes having a breathing hole  an the bottom,
>> mount the
>> box that no rain and water can penetrate from  the top or sides. If the
>> hole is big enough,
>> eg. 2mm, no pressure  difference is possible and no pumping effect will
>> occur.
>> (If the hole is  too wide, small animals may penetrate).
>> Or,
>> when using a pressure tight  box, it must be stiff and sealed to
>> withstand under all
>> temperature  conditions more then 1 bar/ 100 kPa. Do not forget that
>> all
>> feed
>> throughs must be of real hermetic type, normal coaxial  connectors are
>> not tight!
>> Don't route cables directly in, because no  cable braid or mesh is
>> vapor
>> tight.
>> ___
>> 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.
>
>
> ___
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> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> and follow the instructions there.
>
>



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Re: [time-nuts] wwvb weak on east coast especially when thepre-amps under wa...

[Alan Melia]

Well almost Nigel, if you look at molecule mean velocities they are always
able to diffuse down a concentration gradient (i.e from wet into dry)
despite a small reverse presure gradient. It just takes longer under those
conditions :-))which is often "enough"

Alan G3NYK
- Original Message - 
From: 
To: 
Sent: Tuesday, May 15, 2012 12:01 AM
Subject: Re: [time-nuts] wwvb weak on east coast especially when thepre-amps
under wa...


> The other option of course is to pressurise the box with dry air to ensure
> a positive pressure differential, such that the net flow is always
outwards
> at  all points, but it's probably easier just to provide a drain hole:-)
>
> However, whilst a drain hole will prevent the build up of a lake inside
the
>  enclosure it still doesn't prevent condensation forming on circuit
boards,
> and  powered circuit boards and condensation don't really go well
together.
>
> As per earlier comments, it's quite difficult to keep any externally
> mounted enclosure totally moisture free, so it's much easier to accept the
> inevitable and allow for it.
>
> In a past life I designed quite a few circuit boards that  were required
to
> be fitted in externally mounted vented enclosures, so not  a great deal of
> pressurisation there then:-), and I usually specified that  both sides
> should be sprayed with a plastic coating following final test.
>
> I can't remember now exactly what this stuff was called, but it  was
> readily available in the UK from both RS and Farnell as an aerosol plastic
spray
> that provided a good barrier but was a bit more flexible than the  usual
MOD
> spec conformal coatings.
> It melted easily under a soldering iron, albeit with a foul  pong:-), so
> reworking was no problem, and resisted moisture remarkably  well.
>
> problem solved:-)
>
> Nigel
> GM8PZR
>
>
>
>
>
> In a message dated 14/05/2012 23:10:30 GMT Daylight Time,
> arnold.ti...@gmx.de writes:
>
> The only  solutions I think:
> Apply air pressure tight boxes having a breathing hole  an the bottom,
> mount the
> box that no rain and water can penetrate from  the top or sides. If the
> hole is big enough,
> eg. 2mm, no pressure  difference is possible and no pumping effect will
> occur.
> (If the hole is  too wide, small animals may penetrate).
> Or,
> when using a pressure tight  box, it must be stiff and sealed to
> withstand under all
> temperature  conditions more then 1 bar/ 100 kPa. Do not forget that  all
> feed
> throughs must be of real hermetic type, normal coaxial  connectors are
> not tight!
> Don't route cables directly in, because no  cable braid or mesh is  vapor
> tight.
> ___
> 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.


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Re: [time-nuts] Why are 1PPS signals so skinny?

[Bob Camp]

Hi

I would bet that the basic electrical definition of the "skinny" PPS dates at 
least to the mid 50's if not earlier. 

Bob

On May 14, 2012, at 3:20 PM, Magnus Danielson wrote:

> Mark, Azelio and Björn,
> 
> On 05/14/2012 06:33 PM, b...@lysator.liu.se wrote:
>> Mark&  Azelio,
>> 
>> Or even 10V into 50ohm, 20us... See figure 3-4 in ICD-GPS-060.
>> 
>> http://www.navcen.uscg.gov/pdf/gps/ICD-GPS-060B.pdf
>> 
>> More modern 3-5.5V into 50ohm, 20us.
>>  
>> http://contracting.tacom.army.mil/majorsys/jab/DAGR%20Interface%20Specification.pdf
>> 
>> Above are two standards demanding short skinny 1PPS pulses. Are there any
>> other standards with distinct shape requirements on 1PPS pulses?
> 
> You need to look at MIL STD 188/155 which if I recall things was initially 
> formed in the 60thies.
> 
> An AccuBeat presentation actually says that the PPS was originally defined in 
> it.
> 
> The MIL STD 188/155 is actually a 10 V peak level, so it was much hotter than 
> we are used to know. It specified 5 MHz as base frequency, or power of 2 
> multiples (10, 20, 40 MHz... ).
> 
> It was later reformulated in the PTTI spec, which ICD GPS 060 is a derivate. 
> The 50 ns rise and 1 us fall slopes comes from that spec.
> 
> I was not able to find MIL STD 188-155 on the net right now, but I have been 
> able to download it before, so if someone is a more lucky it should surface. 
> I should have my download somewhere.
> 
> Cheers,
> Magnus
> 
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Re: [time-nuts] Why are 1PPS signals so skinny?

[Michael Blazer]

I haven't heard that one before.  I try to slip in the TLAR check in all 
the test procedures I write.  When 'they' ask, I look at it and say: 
"That Looks About Right".

Mike

On 5/14/2012 6:18 PM, Jim Hickstein wrote:

On 2012/05/14 18:02, time-nuts-requ...@febo.com wrote:
https://assist.daps.dla.mil/quicksearch/  is the search site for 
military standards.


Hmm.  Doesn't find MIL-TGDBP-41.  I got this from my (now late) great 
uncle, Bob Sedgwick -- who was to hydraulics what I am to computers, 
only he has a number of patents.


Some smart-aleck at Wright Field, as it then was, put this on a 
drawing, and it went without comment for quite a while until someone 
tried to look it up.  This escalated to a bird colonel, who then 
tracked down the miscreant.


It stands for Make It Like The G-D Blueprint For Once.

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Re: [time-nuts] wwvb weak on east coast especially when the pre-amps under wa...

[Azelio Boriani]

We use the Plastik70 from Kontakt chemie

On Tue, May 15, 2012 at 1:23 AM, Michael Blazer  wrote:

> Here's comparison for various type of conformal coating:
> http://mgchemicals.com/downloads/appguide/appguide0404.pdf.<
> https://assist.daps.dla.mil/quicksearch/>
>
> I think there is a type that is 'serviceable' and removable with alcohol.
>
> Mike
>
>
> On 5/14/2012 6:01 PM, gandal...@aol.com wrote:
>
>> The other option of course is to pressurise the box with dry air to ensure
>> a positive pressure differential, such that the net flow is always
>> outwards
>> at  all points, but it's probably easier just to provide a drain hole:-)
>>
>> However, whilst a drain hole will prevent the build up of a lake inside
>> the
>>  enclosure it still doesn't prevent condensation forming on circuit
>> boards,
>> and  powered circuit boards and condensation don't really go well
>>  together.
>>
>> As per earlier comments, it's quite difficult to keep any externally
>> mounted enclosure totally moisture free, so it's much easier to accept the
>> inevitable and allow for it.
>>
>> In a past life I designed quite a few circuit boards that  were required
>> to
>> be fitted in externally mounted vented enclosures, so not  a great deal of
>> pressurisation there then:-), and I usually specified that  both sides
>> should be sprayed with a plastic coating following final test.
>>
>> I can't remember now exactly what this stuff was called, but it  was
>> readily available in the UK from both RS and Farnell as an aerosol
>> plastic  spray
>> that provided a good barrier but was a bit more flexible than the  usual
>> MOD
>> spec conformal coatings.
>> It melted easily under a soldering iron, albeit with a foul  pong:-), so
>> reworking was no problem, and resisted moisture remarkably  well.
>>
>> problem solved:-)
>>
>> Nigel
>> GM8PZR
>>
>>
>>
>>
>>
>> In a message dated 14/05/2012 23:10:30 GMT Daylight Time,
>> arnold.ti...@gmx.de writes:
>>
>> The only  solutions I think:
>> Apply air pressure tight boxes having a breathing hole  an the bottom,
>> mount the
>> box that no rain and water can penetrate from  the top or sides. If the
>> hole is big enough,
>> eg. 2mm, no pressure  difference is possible and no pumping effect will
>> occur.
>> (If the hole is  too wide, small animals may penetrate).
>> Or,
>> when using a pressure tight  box, it must be stiff and sealed to
>> withstand under all
>> temperature  conditions more then 1 bar/ 100 kPa. Do not forget that  all
>> feed
>> throughs must be of real hermetic type, normal coaxial  connectors are
>> not tight!
>> Don't route cables directly in, because no  cable braid or mesh is  vapor
>> tight.
>> ___
>> 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
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Re: [time-nuts] wwvb weak on east coast especially when the pre-amps under wa...

[Michael Blazer]

Here's comparison for various type of conformal coating: 
http://mgchemicals.com/downloads/appguide/appguide0404.pdf.


I think there is a type that is 'serviceable' and removable with alcohol.

Mike

On 5/14/2012 6:01 PM, gandal...@aol.com wrote:

The other option of course is to pressurise the box with dry air to ensure
a positive pressure differential, such that the net flow is always outwards
at  all points, but it's probably easier just to provide a drain hole:-)

However, whilst a drain hole will prevent the build up of a lake inside the
  enclosure it still doesn't prevent condensation forming on circuit boards,
and  powered circuit boards and condensation don't really go well  together.

As per earlier comments, it's quite difficult to keep any externally
mounted enclosure totally moisture free, so it's much easier to accept the
inevitable and allow for it.

In a past life I designed quite a few circuit boards that  were required to
be fitted in externally mounted vented enclosures, so not  a great deal of
pressurisation there then:-), and I usually specified that  both sides
should be sprayed with a plastic coating following final test.

I can't remember now exactly what this stuff was called, but it  was
readily available in the UK from both RS and Farnell as an aerosol plastic  
spray
that provided a good barrier but was a bit more flexible than the  usual MOD
spec conformal coatings.
It melted easily under a soldering iron, albeit with a foul  pong:-), so
reworking was no problem, and resisted moisture remarkably  well.

problem solved:-)

Nigel
GM8PZR





In a message dated 14/05/2012 23:10:30 GMT Daylight Time,
arnold.ti...@gmx.de writes:

The only  solutions I think:
Apply air pressure tight boxes having a breathing hole  an the bottom,
mount the
box that no rain and water can penetrate from  the top or sides. If the
hole is big enough,
eg. 2mm, no pressure  difference is possible and no pumping effect will
occur.
(If the hole is  too wide, small animals may penetrate).
Or,
when using a pressure tight  box, it must be stiff and sealed to
withstand under all
temperature  conditions more then 1 bar/ 100 kPa. Do not forget that  all
feed
throughs must be of real hermetic type, normal coaxial  connectors are
not tight!
Don't route cables directly in, because no  cable braid or mesh is  vapor
tight.
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Re: [time-nuts] Why are 1PPS signals so skinny?

[Azelio Boriani]

Maybe the correct number is MIL-STD-188-115?

On Tue, May 15, 2012 at 1:18 AM, Jim Hickstein  wrote:

> On 2012/05/14 18:02, time-nuts-requ...@febo.com wrote:
>
>> https://assist.daps.dla.mil/quicksearch/  is the search site for
>> military standards.
>>
>
> Hmm.  Doesn't find MIL-TGDBP-41.  I got this from my (now late) great
> uncle, Bob Sedgwick -- who was to hydraulics what I am to computers, only
> he has a number of patents.
>
> Some smart-aleck at Wright Field, as it then was, put this on a drawing,
> and it went without comment for quite a while until someone tried to look
> it up.  This escalated to a bird colonel, who then tracked down the
> miscreant.
>
> It stands for Make It Like The G-D Blueprint For Once.
>
>
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Re: [time-nuts] Why are 1PPS signals so skinny?

[Jim Hickstein]

On 2012/05/14 18:02, time-nuts-requ...@febo.com wrote:

https://assist.daps.dla.mil/quicksearch/  is the search site for military 
standards.


Hmm.  Doesn't find MIL-TGDBP-41.  I got this from my (now late) great uncle, Bob 
Sedgwick -- who was to hydraulics what I am to computers, only he has a number 
of patents.


Some smart-aleck at Wright Field, as it then was, put this on a drawing, and it 
went without comment for quite a while until someone tried to look it up.  This 
escalated to a bird colonel, who then tracked down the miscreant.


It stands for Make It Like The G-D Blueprint For Once.

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Re: [time-nuts] wwvb weak on east coast especially when the pre-amps under wa...

[GandalfG8]

The other option of course is to pressurise the box with dry air to ensure  
a positive pressure differential, such that the net flow is always outwards 
at  all points, but it's probably easier just to provide a drain hole:-)
 
However, whilst a drain hole will prevent the build up of a lake inside the 
 enclosure it still doesn't prevent condensation forming on circuit boards, 
and  powered circuit boards and condensation don't really go well  together.
 
As per earlier comments, it's quite difficult to keep any externally  
mounted enclosure totally moisture free, so it's much easier to accept the  
inevitable and allow for it.
 
In a past life I designed quite a few circuit boards that  were required to 
be fitted in externally mounted vented enclosures, so not  a great deal of 
pressurisation there then:-), and I usually specified that  both sides 
should be sprayed with a plastic coating following final test.
 
I can't remember now exactly what this stuff was called, but it  was 
readily available in the UK from both RS and Farnell as an aerosol plastic  
spray 
that provided a good barrier but was a bit more flexible than the  usual MOD 
spec conformal coatings.
It melted easily under a soldering iron, albeit with a foul  pong:-), so 
reworking was no problem, and resisted moisture remarkably  well.
 
problem solved:-)
 
Nigel
GM8PZR
 
 
 
 
 
In a message dated 14/05/2012 23:10:30 GMT Daylight Time,  
arnold.ti...@gmx.de writes:

The only  solutions I think:
Apply air pressure tight boxes having a breathing hole  an the bottom,
mount the
box that no rain and water can penetrate from  the top or sides. If the
hole is big enough,
eg. 2mm, no pressure  difference is possible and no pumping effect will
occur.
(If the hole is  too wide, small animals may penetrate).
Or,
when using a pressure tight  box, it must be stiff and sealed to
withstand under all
temperature  conditions more then 1 bar/ 100 kPa. Do not forget that  all
feed
throughs must be of real hermetic type, normal coaxial  connectors are
not tight!
Don't route cables directly in, because no  cable braid or mesh is  vapor
tight.
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Re: [time-nuts] Why are 1PPS signals so skinny?

[Michael Blazer]

Magnus,
https://assist.daps.dla.mil/quicksearch/  is the search site for 
military standards.  MIL-188-155 is not found.  Could it be another dash 
number?

Mike

On 5/14/2012 2:20 PM, Magnus Danielson wrote:

Mark, Azelio and Björn,

On 05/14/2012 06:33 PM, b...@lysator.liu.se wrote:

Mark&  Azelio,

Or even 10V into 50ohm, 20us... See figure 3-4 in ICD-GPS-060.

 http://www.navcen.uscg.gov/pdf/gps/ICD-GPS-060B.pdf

More modern 3-5.5V into 50ohm, 20us.
  
http://contracting.tacom.army.mil/majorsys/jab/DAGR%20Interface%20Specification.pdf


Above are two standards demanding short skinny 1PPS pulses. Are there 
any

other standards with distinct shape requirements on 1PPS pulses?


You need to look at MIL STD 188/155 which if I recall things was 
initially formed in the 60thies.


An AccuBeat presentation actually says that the PPS was originally 
defined in it.


The MIL STD 188/155 is actually a 10 V peak level, so it was much 
hotter than we are used to know. It specified 5 MHz as base frequency, 
or power of 2 multiples (10, 20, 40 MHz... ).


It was later reformulated in the PTTI spec, which ICD GPS 060 is a 
derivate. The 50 ns rise and 1 us fall slopes comes from that spec.


I was not able to find MIL STD 188-155 on the net right now, but I 
have been able to download it before, so if someone is a more lucky it 
should surface. I should have my download somewhere.


Cheers,
Magnus

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Re: [time-nuts] wwvb weak on east coast especially when the pre-amps under water.

[Arnold Tibus]

Am 14.05.2012 21:54, schrieb Hal Murray:
> mag...@rubidium.dyndns.org said:
>> I had the same problem with a GPS antenna at work. Somebody had put the
>> manufactures label over the porus plug that should have vented out any
>> water... but it didn't so I had too high water-level inside the antenna. 
> How does water get in?
>
> I'm not doubting that it does, just trying to understand the mechanism.
>
Let me try to explain it.
The mechanism is as follows:

Air does contain water in form of gas (vapour) which does condense to
water when
the temperature drops down (eg. at night). The problem is coming up on
tight boxes
having a pressure leak eg. due to defective sealing, cracks or via non
hermetic cable
connections. Changing air pressure do always pump in fresh and humid air
and the
condensed water remain on the bottom inside the box and may as well
penetrate into
the wire mesh/ braid of coaxial cables. The copper will start "modering"
and turn black.

The only solutions I think:
Apply air pressure tight boxes having a breathing hole an the bottom,
mount the
box that no rain and water can penetrate from the top or sides. If the
hole is big enough,
eg. 2mm, no pressure difference is possible and no pumping effect will
occur.
(If the hole is too wide, small animals may penetrate).
Or,
when using a pressure tight box, it must be stiff and sealed to
withstand under all
temperature conditions more then 1 bar/ 100 kPa. Do not forget that all
feed
throughs must be of real hermetic type, normal coaxial connectors are
not tight!
Don't route cables directly in, because no cable braid or mesh is vapor
tight.

I hope this will help,
we had never problems that way.

Arnold

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Re: [time-nuts] wwvb weak on east coast especially when the pre-amps under water.

[Joseph M Gwinn]

time-nuts-boun...@febo.com wrote on 05/14/2012 05:04:13 PM:

> From: paul swed 
> To: Discussion of precise time and frequency measurement  n...@febo.com>
> Date: 05/14/2012 05:04 PM
> Subject: Re: [time-nuts] wwvb weak on east coast especially
> when the pre-amps under water.
> Sent by: time-nuts-boun...@febo.com
>
> Magnus is right lots of ways for water to sneak in.
> So I have not had time to figure it out yet. But it is a copperloop and I
> suspect the place it's joining the preamp box lets water in over time.
The
> fact is even a small pin hole that allows air in and out that's humid can
> allow water buildup.

Atmospheric pressure variation, even without wind pressure, is about +/-
10% at the extremes, and it's essentially impossible to make ordinary stuff
hermetic enough to prevent breathing.  The classic dodge is to connect a
long tube to the enclosure, with the tube having sufficient volume that the
breathing is restricted to the tube.  Or, have the tube connect to a
conditioned space, like the house.  Then, the inevitable small leaks no
longer matter as the tube equalizes the pressure.

The extreme example of isolation using a tube is Pasteur's swan neck flask.


Modern outdoor enclosures use a filter of some kind, but the underlying
principle is the same.
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Re: [time-nuts] wwvb weak on east coast especially when the pre-amps under water.

[Magnus Danielson]

On 05/14/2012 11:04 PM, paul swed wrote:

Magnus is right lots of ways for water to sneak in.
So I have not had time to figure it out yet. But it is a copper loop and I
suspect the place its joining the preamp box let water in over time. The
fact is even a small pin hole that allows air in and out thats humid can
allow water buildup. But this is a lot and I need to figure out what
happened. Its a homebrew antenna but am sure over years even the best can
leak. Its about  2ft loop and I had been doing calcs on a 10 ft square loop
and such.
I suspect that would help quite a bit on the east coast. Time will tell.
Still doing a bit of planning and will need to sink some piers for that
size of an antenna.


The antenna which failed was actually quite impressively built. It was 
well built, but failed in assembly. It's replacement, the same model, 
have not failed since.


One of the things to care about is to not let there be a natural place 
for water to build up on a joint into the sensitive stuff. If you have a 
copper loop, then I would turn the tubing upwards into the box rather 
than on the sides of it, such that water drops of the downside rather 
than rest on box, and then have some angled ceiling over the "box".


Cheers,
Magnus

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Re: [time-nuts] wwvb weak on east coast especially when the pre-amps under water.

[paul swed]

Magnus is right lots of ways for water to sneak in.
So I have not had time to figure it out yet. But it is a copper loop and I
suspect the place its joining the preamp box let water in over time. The
fact is even a small pin hole that allows air in and out thats humid can
allow water buildup. But this is a lot and I need to figure out what
happened. Its a homebrew antenna but am sure over years even the best can
leak. Its about  2ft loop and I had been doing calcs on a 10 ft square loop
and such.
I suspect that would help quite a bit on the east coast. Time will tell.
Still doing a bit of planning and will need to sink some piers for that
size of an antenna.
Regards
Paul.

On Mon, May 14, 2012 at 4:11 PM, Jim Hickstein  wrote:

> > How does water get in?
>
> Is this a Spectracom 8206?  Should I worry about mine (that one that's
> outdoors)?
>
>
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Re: [time-nuts] Why are 1PPS signals so skinny?

[Azelio Boriani]

OK, thank you for the references.

On Mon, May 14, 2012 at 9:20 PM, Magnus Danielson <
mag...@rubidium.dyndns.org> wrote:

> Mark, Azelio and Björn,
>
> On 05/14/2012 06:33 PM, b...@lysator.liu.se wrote:
>
>> Mark&  Azelio,
>>
>> Or even 10V into 50ohm, 20us... See figure 3-4 in ICD-GPS-060.
>>
>> http://www.navcen.uscg.gov/pdf/gps/ICD-GPS-060B.pdf
>>
>> More modern 3-5.5V into 50ohm, 20us.
>>
>> http://contracting.tacom.army.mil/majorsys/jab/DAGR%20Interface%20Specification.pdf
>>
>> Above are two standards demanding short skinny 1PPS pulses. Are there any
>> other standards with distinct shape requirements on 1PPS pulses?
>>
>
> You need to look at MIL STD 188/155 which if I recall things was initially
> formed in the 60thies.
>
> An AccuBeat presentation actually says that the PPS was originally defined
> in it.
>
> The MIL STD 188/155 is actually a 10 V peak level, so it was much hotter
> than we are used to know. It specified 5 MHz as base frequency, or power of
> 2 multiples (10, 20, 40 MHz... ).
>
> It was later reformulated in the PTTI spec, which ICD GPS 060 is a
> derivate. The 50 ns rise and 1 us fall slopes comes from that spec.
>
> I was not able to find MIL STD 188-155 on the net right now, but I have
> been able to download it before, so if someone is a more lucky it should
> surface. I should have my download somewhere.
>
> Cheers,
> Magnus
>
>
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Re: [time-nuts] wwvb weak on east coast especially when the pre-amps under water.

[Jim Hickstein]

> How does water get in?

Is this a Spectracom 8206?  Should I worry about mine (that one that's 
outdoors)?

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Re: [time-nuts] wwvb weak on east coast especially when the pre-amps under water.

[Magnus Danielson]

Hal,

On 05/14/2012 09:54 PM, Hal Murray wrote:


mag...@rubidium.dyndns.org said:

I had the same problem with a GPS antenna at work. Somebody had put the
manufactures label over the porus plug that should have vented out any
water... but it didn't so I had too high water-level inside the antenna.


How does water get in?

I'm not doubting that it does, just trying to understand the mechanism.


There are many ways. No of the joints is perfectly water-blocking, and 
the plastic itself isn't perfectly water-rejecting. Water will get in 
there, so you better leak it out. It was the build-up that killed it, 
not the smaller amounts of water in itself.


Cheers,
Magnus

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Re: [time-nuts] wwvb weak on east coast especially when the pre-amps under water.

[Hal Murray]

mag...@rubidium.dyndns.org said:
> I had the same problem with a GPS antenna at work. Somebody had put the
> manufactures label over the porus plug that should have vented out any
> water... but it didn't so I had too high water-level inside the antenna. 

How does water get in?

I'm not doubting that it does, just trying to understand the mechanism.


-- 
These are my opinions.  I hate spam.




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Re: [time-nuts] wwvb weak on east coast especially when the pre-amps under water.

[Magnus Danielson]

Paul,

On 05/14/2012 09:46 PM, paul swed wrote:

Magnus
Yes indeed will be working tonight. At least the preamp.Need to figure out
what was leaking yet. A bit messy but no real damage and it uses nothing
but simple parts.


Good to hear.


It also allowed water into the coax so will need to chop 3ft off and put a
new connector on. Minor stuff.


I was thinking... would adding an additional resistor to add DC load 
assist in keeping the amp fairly damp-free and also help to keep the 
cable on the dry side?


Cheers,
Magnus

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Re: [time-nuts] wwvb weak on east coast especially when the pre-amps under water.

[paul swed]

Magnus
Yes indeed will be working tonight. At least the preamp.Need to figure out
what was leaking yet. A bit messy but no real damage and it uses nothing
but simple parts.
It also allowed water into the coax so will need to chop 3ft off and put a
new connector on. Minor stuff.
Regards
Paul.

On Mon, May 14, 2012 at 3:33 PM, Magnus Danielson <
mag...@rubidium.dyndns.org> wrote:

> Paul.
>
>
> On 05/14/2012 07:20 PM, paul swed wrote:
>
>> Thanks everyone yesterday for your wwvb comment. I now know why the wwvb
>> signal droped to -120db.
>> Seems that over 4 years water slowly built up in the preamp housing. Water
>> and rust do make fine conductors.
>>
>
> I had the same problem with a GPS antenna at work. Somebody had put the
> manufactures label over the porus plug that should have vented out any
> water... but it didn't so I had too high water-level inside the antenna.
>
> Hope you get your amplifier operational again.
>
> Cheers,
> Magnus
>
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Re: [time-nuts] wwvb weak on east coast especially when the pre-amps under water.

[Magnus Danielson]

Paul.

On 05/14/2012 07:20 PM, paul swed wrote:

Thanks everyone yesterday for your wwvb comment. I now know why the wwvb
signal droped to -120db.
Seems that over 4 years water slowly built up in the preamp housing. Water
and rust do make fine conductors.


I had the same problem with a GPS antenna at work. Somebody had put the 
manufactures label over the porus plug that should have vented out any 
water... but it didn't so I had too high water-level inside the antenna.


Hope you get your amplifier operational again.

Cheers,
Magnus

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Re: [time-nuts] Why are 1PPS signals so skinny?

[Magnus Danielson]

Mark, Azelio and Björn,

On 05/14/2012 06:33 PM, b...@lysator.liu.se wrote:

Mark&  Azelio,

Or even 10V into 50ohm, 20us... See figure 3-4 in ICD-GPS-060.

 http://www.navcen.uscg.gov/pdf/gps/ICD-GPS-060B.pdf

More modern 3-5.5V into 50ohm, 20us.
  
http://contracting.tacom.army.mil/majorsys/jab/DAGR%20Interface%20Specification.pdf

Above are two standards demanding short skinny 1PPS pulses. Are there any
other standards with distinct shape requirements on 1PPS pulses?


You need to look at MIL STD 188/155 which if I recall things was 
initially formed in the 60thies.


An AccuBeat presentation actually says that the PPS was originally 
defined in it.


The MIL STD 188/155 is actually a 10 V peak level, so it was much hotter 
than we are used to know. It specified 5 MHz as base frequency, or power 
of 2 multiples (10, 20, 40 MHz... ).


It was later reformulated in the PTTI spec, which ICD GPS 060 is a 
derivate. The 50 ns rise and 1 us fall slopes comes from that spec.


I was not able to find MIL STD 188-155 on the net right now, but I have 
been able to download it before, so if someone is a more lucky it should 
surface. I should have my download somewhere.


Cheers,
Magnus

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Re: [time-nuts] Why are 1PPS signals so skinny?

[Rick Karlquist]

Mark Sims wrote:
>
> My first inclination,  if I were building a timing receiver,  would be to
> make the PPS output a nice,  symmetrical square wave.   But pretty much
> all GPS timing receivers output an anorexic,  dinky little heroin addicted
> supermodel sized pulse (from 1 to 150uS wide is typical).
> ___

One reason might be that it is convenient to have AC coupled
hardware, with a reasonable low frequency cutoff.  1 Hz is
not a reasonable low frequency cutoff, which is what you
would need if a square wave were used.  (Actually, to accurately
reproduce a 1 Hz square wave requires response down to .1 Hz
and preferrably .01 Hz, due to droop and phase shift distortion
issues).   A short pulse will conveniently propagate though
the same sort of distribution amplifiers used for 10 MHz, 5 MHz,
100 kHz, etc.

Rick Karlquist N6RK


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[time-nuts] Trimble Resolution SMT - good/bad/indifferent?

[Mark Sims]

Well,  the connector is a standard connector...  it's just 2mm/0.070" spacing.  

I would not trust a dropping resistor.  The current consumption on these units 
does not appear to be constant...  the temperature plot varies depending upon 
what it is doing (i.e. gets  warmer when acquiring satellites, etc).I also wire 
wrapped to mine.   Those wires were then wrapped to a 14 pin wire-wrap socket.  
I plugged a 3.3V TO-220 LDO regulator (big smoke free hint: their pinouts are 
not IN-GND-OUT) into the socket and powered it off a 5V wall wart (5V to the 
antenna power pin).  For RS-232 out,  I used a RS-232 level converter cable 
(http://www.ebay.co.uk/itm/ws/eBayISAPI.dll?ViewItem&item=221005883442) and 
shoved the single-pin headers on the end of that cable onto the wire wrap 
socket pins.  It took about 10 minutes to get it all connected and running.

Note that these units do not speak TSIP by default.  They are a special version 
that acts like a Motorola receiver.  You have to reconfigure them if you want 
to use Lady Heather (who now speaks to Resolution-T and -SMT).  

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Re: [time-nuts] Why are 1PPS signals so skinny?

[Chris Albertson]

You don't want it symmetric.  If it were then you'd not be able to
notice if it was inverted.   You need the asymmetry but the next
question is "how asymmetric?"   In theory all the information is on
the raising edge of the pulse so you cam make it as short as you like
and not loose any information.OK so that sets the limits on both
ends.Next thing, I'd guess is power, a low duty cycle certainly
uses less power.

On Mon, May 14, 2012 at 8:23 AM, Mark Sims  wrote:
>
> My first inclination,  if I were building a timing receiver,  would be to 
> make the PPS output a nice,  symmetrical square wave.   But pretty much all 
> GPS timing receivers output an anorexic,  dinky little heroin addicted 
> supermodel sized pulse (from 1 to 150uS wide is typical).
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-- 

Chris Albertson
Redondo Beach, California

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Re: [time-nuts] Trimble Resolution SMT - good/bad/indifferent?

[David J Taylor]

I see the Trimble Resolution SMT Timing GPS OEM board 66974-35 on a 
well-known auction site from a weel-know seller "fluke.i", at quite a 
good price, and free UK post.  Is it any good - as good it seems to be. 
Any experience?


Just to report back that I eventually got round to powering up one of the 
two units I bought, having found an SMB connector, and having decided to 
"wire-wrap" the 8-pin connector (a non-standard spacing), and having 
decided to power the unit from 5V USB through a 16-ohm dropper to get the 
3.3V it needs!


Initially, it didn't seem to be working, as there was no serial output and 
the LED I had connected via a 1.5K to PPS output wasn't flashing. 
However, when I put the 'scope on the PPS signal, it locked and showed a 
pulse of just over 100 microseconds.  Much shorter than I had expected 
(but I hadn't read the manual in detail).  The timing was within a 
fraction of a microsecond of other PPS sources.  On disconnecting the 
power, and re-applying it, the PPS signal returned after about 45 seconds.


So on that basis, I'm happy.  I've not tried it as a source for NTP.

 
http://i.ebayimg.com/00/s/NDI0WDY0MA==/$(KGrHqZHJ!4E9qHIuLeNBPkC5j4p8Q~~60_3.JPG

No programming needed, I just powered it up.

Cheers,
David
--
SatSignal software - quality software written to your requirements
Web:  http://www.satsignal.eu
Email:  david-tay...@blueyonder.co.uk 



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Re: [time-nuts] Lucent 40 dB Antenna

[David J Taylor]

I bought mine because of the gain, but on +5V it performs worse than a 
"38 dBi" antenna, quite a lot worse.  I'm wonder whether it needs more 
volts, or whether it's simply broken.  It was ex-equipment, and not in 
very good shape, but it was described as "used" so I'll just write off 
the loss, I suppose.


Update, I mentioned the problem to the seller, and got an immediate fill 
refund.  Nice to have no arguments!


Cheers,
David
--
SatSignal software - quality software written to your requirements
Web:  http://www.satsignal.eu
Email:  david-tay...@blueyonder.co.uk 



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[time-nuts] wwvb weak on east coast especially when the pre-amps under water.

[paul swed]

Thanks everyone yesterday for your wwvb comment. I now know why the wwvb
signal droped to -120db.
Seems that over 4 years water slowly built up in the preamp housing. Water
and rust do make fine conductors.
May have effected bias just a bit and everything else.
Washed it all out and will let it dry and take a serious look at whats up.
Thanks for the quick replies.
Regards
Paul
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Re: [time-nuts] Why are 1PPS signals so skinny?

[Azelio Boriani]

I thought it was only standard practice, now I see that there are standards
and requirements too.

On Mon, May 14, 2012 at 6:33 PM,  wrote:

> Mark & Azelio,
>
> Or even 10V into 50ohm, 20us... See figure 3-4 in ICD-GPS-060.
>
>http://www.navcen.uscg.gov/pdf/gps/ICD-GPS-060B.pdf
>
> More modern 3-5.5V into 50ohm, 20us.
>
> http://contracting.tacom.army.mil/majorsys/jab/DAGR%20Interface%20Specification.pdf
>
> Above are two standards demanding short skinny 1PPS pulses. Are there any
> other standards with distinct shape requirements on 1PPS pulses?
>
> --
>
>   Björn
>
> > Feed a 5V 1Hz square wave into a 50OHM load and look at the power drain.
> > Do
> > the same with a 100uS pulse and smile at the difference.
> >
> > On Mon, May 14, 2012 at 5:23 PM, Mark Sims  wrote:
> >
> >>
> >> My first inclination,  if I were building a timing receiver,  would be
> >> to
> >> make the PPS output a nice,  symmetrical square wave.   But pretty much
> >> all
> >> GPS timing receivers output an anorexic,  dinky little heroin addicted
> >> supermodel sized pulse (from 1 to 150uS wide is typical).
>
>
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Re: [time-nuts] Why are 1PPS signals so skinny?

[bg]

Mark & Azelio,

Or even 10V into 50ohm, 20us... See figure 3-4 in ICD-GPS-060.

http://www.navcen.uscg.gov/pdf/gps/ICD-GPS-060B.pdf

More modern 3-5.5V into 50ohm, 20us.
 
http://contracting.tacom.army.mil/majorsys/jab/DAGR%20Interface%20Specification.pdf

Above are two standards demanding short skinny 1PPS pulses. Are there any
other standards with distinct shape requirements on 1PPS pulses?

--

   Björn

> Feed a 5V 1Hz square wave into a 50OHM load and look at the power drain.
> Do
> the same with a 100uS pulse and smile at the difference.
>
> On Mon, May 14, 2012 at 5:23 PM, Mark Sims  wrote:
>
>>
>> My first inclination,  if I were building a timing receiver,  would be
>> to
>> make the PPS output a nice,  symmetrical square wave.   But pretty much
>> all
>> GPS timing receivers output an anorexic,  dinky little heroin addicted
>> supermodel sized pulse (from 1 to 150uS wide is typical).


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Re: [time-nuts] Why are 1PPS signals so skinny?

[mike cook]

Le 14/05/2012 17:23, Mark Sims a écrit :

My first inclination,  if I were building a timing receiver,  would be to make 
the PPS output a nice,  symmetrical square wave.   But pretty much all GPS 
timing receivers output an anorexic,  dinky little heroin addicted supermodel 
sized pulse (from 1 to 150uS wide is typical).  
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NAVMAN Jupitr-T26 ms
ONCORE VP ~200ms
   UT+200ms
   M12T  1PPS 200ms 100Hz 2-3ms

these are all timing receivers and the signals will trip serial 
receivers without pulse stretching..


So the picture is not that gloomy.


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Re: [time-nuts] Why are 1PPS signals so skinny?

[Azelio Boriani]

Feed a 5V 1Hz square wave into a 50OHM load and look at the power drain. Do
the same with a 100uS pulse and smile at the difference.

On Mon, May 14, 2012 at 5:23 PM, Mark Sims  wrote:

>
> My first inclination,  if I were building a timing receiver,  would be to
> make the PPS output a nice,  symmetrical square wave.   But pretty much all
> GPS timing receivers output an anorexic,  dinky little heroin addicted
> supermodel sized pulse (from 1 to 150uS wide is typical).
> ___
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[time-nuts] Why are 1PPS signals so skinny?

[Mark Sims]

My first inclination,  if I were building a timing receiver,  would be to make 
the PPS output a nice,  symmetrical square wave.   But pretty much all GPS 
timing receivers output an anorexic,  dinky little heroin addicted supermodel 
sized pulse (from 1 to 150uS wide is typical).  
  
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Re: [time-nuts] Re Shera Controller - U7

[EWKehren]

I also located a couple of units in my inventory. But U 7 is not critical,  
it was at the time an elegant way to perform two functions. Now that it is 
not  readily available the fix is to use a 6 MHz resonator between pin 9 and 
10 on  the PIC. 6 MHz is not critical for the over all function except it 
sets the  RS232 baud rate. 24 MHz is not critical either except it has to be 
a frequency  the HC4520 can handle. Changing Frequency will change range and 
 resolution. 
Brooks has a later version of the PIC available (V402) but since he has not 
 responded to my emails I do not know how it exactly differs from V133. I 
use 133  and have excellent results tailored to my needs by modifying 
circuits around it  like automatic filter sequencing in case of power failure, 
using 100 MHz counter  and dividing interrupts by 4 to increase sample size.
Since I have extra unmodified A&A boards with the 16C73 for the fun of  it 
we ran a unit tying it directly to a Morion MV89 and got 3 E-12! No 
matching.  Next we will do the same with a FEI 5680 controlling the C field and 
it  
will require some matching so I expect 2 E-13. Again nothing changed on the  
A&A board.
I have extra populated A&A boards and AD 1861's,  if any one is  interested 
contact me off list
Bert Kehren
 
 
 
In a message dated 5/14/2012 9:57:25 A.M. Eastern Daylight Time,  
vk6...@iinet.net.au writes:

Hi Kevin  - I have a spare I can send you.   I responded direct to your 
email  
but no reply.

Merv  VK6BMT  


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Re: [time-nuts] Manual or Software for FEI Pico Sync?

[Brooke Clarke]

Hi Sam:

Thanks.  After adding .exe to the file name it installs and runs.
Now the problem is the connector on the Pico Sync, it's a DB-9m, unlike the DB-9f on the Thunderbolt and most of my 
other RS-232 stuff.


Have Fun,

Brooke Clarke
http://www.PRC68.com
http://www.end2partygovernment.com/Clarke4Congress.html


Sam wrote:

I wonder if the PicoSync-II software would be compatible?

http://support.fei-zyfer.com/95_download.aspx





Hi:

Is there a manual, data sheet, docs of any kind or software for the FEI Pico
Sync?
http://www.prc68.com/I/FEIFS.shtml#Picosync

--
Have Fun,

Brooke Clarke
http://www.PRC68.com
http://www.end2partygovernment.com/Clarke4Congress.html


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[time-nuts] Re Shera Controller - U7

[Merv Thomas]

Hi Kevin - I have a spare I can send you.   I responded direct to your email 
but no reply.


Merv  VK6BMT 



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Re: [time-nuts] Shera Controller - U7

[Azelio Boriani]

Yes, that was my intention: I posted the VHDL of the TimeToDigital TIC I
use. Next will be the PI controller. I hope this short roadmap will lead to
the evolution of the Shera controller.

On Mon, May 14, 2012 at 4:37 AM, J. L. Trantham  wrote:

> I have always been interested in trying to improve the look of the 'dead
> bug' style.
>
> How about a small PCB with an 8 pin DIP connector that is used to mount the
> oscillator, the divide by 4 and get power, ground and provide 24 MHz and 6
> MHz outputs to the 8 pin DIP.  That way, the 'little module' plugs into the
> original socket on the PCB.  In addition, if the correct part ever becomes
> available, it's just 'unplug and play'.
>
> Lot's more effort but it sure would look good.  Might also allow for some
> modifications to raise the 24 MHz and achieve smaller phase increment
> corrections.
>
> Likewise, a module could be built to plug into U2 to provide for a 10 MHz
> VCXO and with jumpers for whatever frequency VCXO you might choose.  As
> designed, the controller is good to 5 MHz or so.
>
> Come to think about it, is it time to think about a 21'st century Shera
> Controller re-design?  Or has the TBolt made that obsolete?
>
> Joe
>
> -Original Message-
> From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
> Behalf Of shali...@gmail.com
> Sent: Sunday, May 13, 2012 9:08 PM
> To: kevin.sta...@virgin.net; Time-Nuts
> Subject: Re: [time-nuts] Shera Controller - U7
>
> A 74AC74 in SO-14 package mounted dead bug style will make a handy /4 that
> is no bigger than most crystal oscillators.
>
> If that's still too big, you can go with the TSSOP, but no coffee for you
> for a week prior to soldering that baby :)
>
> Didier KO4BB
>
> Sent from my BlackBerry Wireless thingy while I do other things...
>
> -Original Message-
> From: "Kevin Staley" 
> Sender: time-nuts-boun...@febo.com
> Date: Sun, 13 May 2012 17:27:20
> To: 'Discussion of precise time and frequency
> measurement'
> Reply-To: kevin.sta...@virgin.net,
>Discussion of precise time and frequency measurement
>
> Subject: Re: [time-nuts] Shera Controller - U7
>
> Hi all
> Thanks for the many responses.
> It would seem that U7 is pretty rare.
> I think I will be going with a 24 MHz "Can oscillator" and a separate 6MHz
> source for the PIC either divided from the 24MHz oscillator or a separate
> oscillator.
>
> Thanks again
> Kevin
>
>
> -Original Message-
> From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
> Behalf Of Chris Albertson
> Sent: 13 May 2012 16:47
> To: Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] Shera Controller - U7
>
> On Sun, May 13, 2012 at 8:11 AM, J. L. Trantham  wrote:
> > It is an 8 pin DIP, 24 MHz oscillator with an onboard divide output in
> > order to provide a dual output oscillator.  It is an ECS-300CX-240 and
> > DigiKey lists it as obsolete since 2009.  They say 'call'.
>
> Sounds like a you could use a normal 24MHz TTL can oscillator and a dual
> flip flop mounted "dead bug" style.
>
> Chris Albertson
> Redondo Beach, California
>
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Re: [time-nuts] Tektronix Manuals

[Azelio Boriani]

Yes, interesting.
Thanks

On Mon, May 14, 2012 at 12:16 AM, paul swed  wrote:

> Good site had not run into it before
> Thanks
>
> On Sat, May 12, 2012 at 6:54 PM, J. Forster  wrote:
>
> > Hi,
> >
> > I fround this site this evening:
> >
> > http://w140.com/tekwiki/wiki/Main_Page
> >
> > The scans are not as good as some commercial pones, but the price is
> > right. It has manuals that are not available on BAMA or the other sites I
> > checked.
> >
> > Best,
> >
> > -John
> >
> > 
> >
> >
> > ___
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Re: [time-nuts] Manual or Software for FEI Pico Sync?

[Sam]

I wonder if the PicoSync-II software would be compatible?

http://support.fei-zyfer.com/95_download.aspx




> Hi:
> 
> Is there a manual, data sheet, docs of any kind or software for the FEI Pico
> Sync?
> http://www.prc68.com/I/FEIFS.shtml#Picosync
> 
> -- 
> Have Fun,
> 
> Brooke Clarke
> http://www.PRC68.com
> http://www.end2partygovernment.com/Clarke4Congress.html
> 
> 
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