Re: [time-nuts] HP 5065A super

[Dana Whitlow]

Keep in mind that soldermask will also change the field distributions
around a
microstrip line, and will somewhat mitigate the microstrip's dispersive
behavior
as well.

I once worked with some miccrostrip couplers at around 2-4 GHz and found
that
directivity was significantly improved by adding two layers of thin kapton
tape
on top of the coupled region, a solution that went into production.  I
expect that
the usual soldermask layer would have about the same effect.

Dana


On Thu, Feb 22, 2018 at 8:15 PM, jimlux  wrote:

> On 2/22/18 12:29 PM, Leo Bodnar wrote:
>
>> Here is ENIG fact that is not widely known at the moment but which some
>> might find useful.
>>
>> I could not understand why I get better TDR and insertion loss results
>> from solder-mask covered microstrip transmission lines than from otherwise
>> identical microstrips on the same substrate with soldermask removed and,
>> therefore, covered with ENIG.
>>
>> Gold can't be bad, right? As it turns out, even gold coin has two sides
>> to it.
>>
>> I have found that Shlepnev and McMorrow conducted extensive research and
>> published data, some of which is presented here
>> http://www.simberian.com/Presentations/NickelCharacterizatio
>> nPresentation_emc2011.pdf
>>
>>
> the ever useful http://www.microwaves101.com/ site has an excellent
> discussion of this under the "skin effect" heading.
>
>
>
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[time-nuts] Chinese made eBay antenna breakdown.

[John Green]

I didn't mean to imply that all Chinese made products are garbage. But,
some of them are. And, has been said, that is because people want to pay
the absolute lowest prices for stuff. The company I recently retired from
has a long history with Chinese competition. We had a product that had but
one American competitor. We thought, foolishly, that being a low cost item
with a modest annual sales volume, he wouldn't have to worry about foreign
competition. We didn't take into account our main customer who would slit
your throat over a tenth of a cent. It wasn't long before we began seeing
competing products from China. At first, they either did what was cheapest
without regard for RF concerns, or they copied us exactly. However, in
recent years, I have seen Chinese products that show the result of some
real engineering talent. In some cases, they are better than ours. These
are parts that are molded in plastic, and the foreign competition certainly
knows a lot more about molding than we do. Their parts are cosmetically
superior to ours in almost every instance. Lately, I have suggested that we
obtain some of these products and copy them. That is what it has come to.
I noticed that the enable input is tied to the voltage input. I thought
that it may have seen too high a voltage, but the specs say it should be
able to take 20 volts. So, I don't really see any reason it should have
failed. I will put a new 3.3 volt regulator in and see if I can get it to
work. I want to do comparisons to other antennas. The rest of the circuitry
looks OK to me.
There is one SAW bandpass filter per band. Not like the Trimble, but should
work fine for my purposes.
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[time-nuts] Curious, how many t-nuts have 5065A

[Skip Withrow]

Hello Time-Nuts,

Pete Lancashire was wondering how many HP 5065As are out there.  I
don't know the exact number, but I know there are a lot.  I think
Corby (or someone) had a list of serial numbers at one time.

I will confess that I do have one - and love it.  It is a very old
unit that doesn't have any updates other than a few new electrolytics
and a finer adjustment on the C-field.

Attached is a plot of it for the last three days.  I have not touched
it in several months.  It is not in a particularly well controlled
temperature environment (the yellow line on the graph), and it moved
110ns in three days (4.23x10E-13 frequency error).  And most of the
noise on the purple line (5065A frequency) is due to the GPS reference
(NTBW50AA does not have a great antenna as indicated by the bottom GPS
line).

Skip Withrow
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[time-nuts] Lady Heather v6.0 Beta for Windows .EXE file

[Mark Sims]

I have had a LOT of requests for the Windows version of the latest version 
(v6.0 Beta) of Lady Heather for Windows.   Unfortunately aggressive blocking of 
.exe files by ISPs makes it very hard to email the .exe file (even password 
protected .zip files get blocked).  Also very few Windows users seem to be able 
to compile the code.

I've put a copy of the Windows .exe and documentation comments on EEVBLOG:
http://www.eevblog.com/forum/metrology/lady-heather-v6-beta-for-windows-exe/msg1434005/#msg1434005

This is just the .exe  To use it you will need to have v5.0 installed and 
working (from ke5fx.com) and replace the v5.0 heather.exe file with this one 
(backup your old .exe first).

This version supports LOTs of new devices (including TruePosition, PRS10, X72, 
and SA22.c devices) and has a lot of new features.  Check the heather.txt file 
for the command line options for selecting your device type and the new 
features.
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Re: [time-nuts] Teardown of Chinese made eBay GPS antenna.

[Ruslan Nabioullin]

On Thu, Feb 22, 2018 at 5:48 PM, djl  wrote:
> Fine. The Chinese have no concept of, or ignore, intellectual property
> rights.

Which is not necessarily perverse---there exist people (most notably
those of the so-called Pirate Party movements worldwide) who deem the
legal theories of the copyright and the patent to be absurd.  That is
all that I will say, for I do not wish to excessively deviate from the
topic of discourse.

-Ruslan

-- 
Ruslan Nabioullin
Wittgenstein Laboratories
rnabioul...@gmail.com
(508) 523-8535
50 Louise Dr.
Hollis, NH 03049
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Re: [time-nuts] HP 5065A super

[Bob kb8tq]

Hi

The same nickel plating effect gets into a lot of things. If you are shopping 
for very 
low IMD connectors, nickel plating is out. Things get non-linear (to a very 
slight 
degree) when it is present. If -180 db is the goal for those spurs, you might 
only
hit -120 db with the nickel connectors …..

Bob

> On Feb 22, 2018, at 9:15 PM, jimlux  wrote:
> 
> On 2/22/18 12:29 PM, Leo Bodnar wrote:
>> Here is ENIG fact that is not widely known at the moment but which some 
>> might find useful.
>> I could not understand why I get better TDR and insertion loss results from 
>> solder-mask covered microstrip transmission lines than from otherwise 
>> identical microstrips on the same substrate with soldermask removed and, 
>> therefore, covered with ENIG.
>> Gold can't be bad, right? As it turns out, even gold coin has two sides to 
>> it.
>> I have found that Shlepnev and McMorrow conducted extensive research and 
>> published data, some of which is presented here 
>> http://www.simberian.com/Presentations/NickelCharacterizationPresentation_emc2011.pdf
> 
> the ever useful http://www.microwaves101.com/ site has an excellent 
> discussion of this under the "skin effect" heading.
> 
> 
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Re: [time-nuts] Curious, how many t-nuts have 5065A

[Andy ZL3AG via time-nuts]

http://www.timeok.it/hp5065a-corner-3/

See: HP5065asnlist (serial number list)

On 23/02/2018, at 3:44 AM, Pete Lancashire wrote:

> no reason other then  curious
> 
> -pete
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Re: [time-nuts] HP 5065A super

[jimlux]

On 2/22/18 12:29 PM, Leo Bodnar wrote:

Here is ENIG fact that is not widely known at the moment but which some might 
find useful.

I could not understand why I get better TDR and insertion loss results from 
solder-mask covered microstrip transmission lines than from otherwise identical 
microstrips on the same substrate with soldermask removed and, therefore, 
covered with ENIG.

Gold can't be bad, right? As it turns out, even gold coin has two sides to it.

I have found that Shlepnev and McMorrow conducted extensive research and 
published data, some of which is presented here 
http://www.simberian.com/Presentations/NickelCharacterizationPresentation_emc2011.pdf



the ever useful http://www.microwaves101.com/ site has an excellent 
discussion of this under the "skin effect" heading.



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Re: [time-nuts] HP 5065A super

[Tom McDermott]

It appears that ENIG gold is extremely thin (2 - 8 microinches),
and if so does not cause a solderability problem.

-- Tom, N5EG



On Thu, Feb 22, 2018 at 3:18 PM, Mark Goldberg 
wrote:

> My reading of IPC J-STD-001F Paragraph 4.5 says that the gold embrittlement
> issue does not apply to ENIG or ENEPIG. Paragraph 4.5.1 does say other gold
> shall be removed so there won't be solder embrittlement.
>
> Is that still correct?
>
> The issue with ENIG and RF is interesting. I have not heard that before but
> I can find lots of info on the subject. I do not remember seeing ENIG on
> microstrip boards.
>
> Regards,
>
> Mark
>
>
> On Thu, Feb 22, 2018 at 2:33 PM, Tom McDermott  wrote:
>
> > In general it's bad practice to gold plate SMT solder pads.  The reason
> is
> > that proper SMT soldering utilizes a very small amount of solder and the
> > gold plating
> > will partially dissolve into the molten solder. Because of the small
> amount
> > of
> > solder, the percentage of gold will be high enough to embrittle the
> solder
> > joint,
> > and it will have a high probability of failure.
> >
> > Hand soldering can apply a large enough amount of solder that the
> > percentage
> > of gold in the joint is relatively small and the problem is avoided.
> >
> > -- Tom, N5EG
> >
> >
> >
> >
> > On Thu, Feb 22, 2018 at 12:29 PM, Leo Bodnar  wrote:
> >
> > > Here is ENIG fact that is not widely known at the moment but which some
> > > might find useful.
> > >
> > > I could not understand why I get better TDR and insertion loss results
> > > from solder-mask covered microstrip transmission lines than from
> > otherwise
> > > identical microstrips on the same substrate with soldermask removed
> and,
> > > therefore, covered with ENIG.
> > >
> > > Gold can't be bad, right? As it turns out, even gold coin has two sides
> > to
> > > it.
> > >
> > > I have found that Shlepnev and McMorrow conducted extensive research
> and
> > > published data, some of which is presented here
> > http://www.simberian.com/
> > > Presentations/NickelCharacterizationPresentation_emc2011.pdf
> > >
> > > In essence, it's not the "G" that is the problem - it is the "N".
> > > Immersion Gold layer is not thick enough to contain whole of the skin
> > > effect layer (even towards 100GHz) and as signal frequency increases
> most
> > > of the signal ends up travelling through Nickel.
> > > As Shlepnev commented "Nickel is the most mysterious metal in
> > > electronics."  It has significant effect on insertion loss and risetime
> > > degradation.  "Significant effect" is posh for "bad."
> > >
> > > Some mass PCB manufacturers have been known to apply ENIG before
> > > soldermasking.  This causes even more high speed/frequency problems
> > because
> > > all of the copper on the outside layers will have Nickel over it -
> > exposed
> > > or not.
> > >
> > > Probably not a problem for majority of ENIG users but could cause a
> > > headache or two for unsuspecting.
> > >
> > > Leo
> > >
> > > > Date: Thu, 22 Feb 2018 19:02:25 +
> > > > From: Mark Sims 
> > > >
> > > > Yes, have the board done with ENIG gold.  It typically adds around
> $15
> > > per run of boards.  I do all my boards with ENIG gold... if for no
> other
> > > reason than the gold color makes it very easy to determine when your
> > solder
> > > paste properly covers the pads.
> > > >
> > > > And, as Charles mentioned,  the quality and thickness of the gold can
> > > vary depending upon the board house.  I have used gojgo.com for a lot
> of
> > > boards.  They do very good, quick work,  are well priced, and they seem
> > to
> > > have the best gold finish.
> > > >
> > > > Hard gold finish is VERY expensive these days.  I've been quoted
> $250+
> > > for setup charges and per-board costs of over $25.
> > >
> > > ___
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> > > To unsubscribe, go to https://www.febo.com/cgi-bin/
> > > mailman/listinfo/time-nuts
> > > and follow the instructions there.
> > >
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> > ailman/listinfo/time-nuts
> > and follow the instructions there.
> >
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Re: [time-nuts] Teardown of Chinese made eBay GPS antenna.

[William H. Fite]

With respect, Tom, discussion of quality issues is scarcely "social media."

But...it is your list so that's the last you'll hear from me on the topic.



On Thursday, February 22, 2018, Tom Van Baak  wrote:

> Let's keep this thread on topic and highly informative.
>
> Please treat time nuts as a technical mailing list, not social media.
>
> Thanks,
> /tvb
> Moderator, www.leapsecond.com/time-nuts.htm
>
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>


-- 
Patriotism is supporting your country all the time, and your government
when it deserves it.
--Mark Twain

We may be surprised at the people we find in heaven. God has a soft spot
for sinners. His standards are quite low.
--Desmond Tutu
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Re: [time-nuts] HP 5065A super

[Mark Goldberg]

My reading of IPC J-STD-001F Paragraph 4.5 says that the gold embrittlement
issue does not apply to ENIG or ENEPIG. Paragraph 4.5.1 does say other gold
shall be removed so there won't be solder embrittlement.

Is that still correct?

The issue with ENIG and RF is interesting. I have not heard that before but
I can find lots of info on the subject. I do not remember seeing ENIG on
microstrip boards.

Regards,

Mark


On Thu, Feb 22, 2018 at 2:33 PM, Tom McDermott  wrote:

> In general it's bad practice to gold plate SMT solder pads.  The reason is
> that proper SMT soldering utilizes a very small amount of solder and the
> gold plating
> will partially dissolve into the molten solder. Because of the small amount
> of
> solder, the percentage of gold will be high enough to embrittle the solder
> joint,
> and it will have a high probability of failure.
>
> Hand soldering can apply a large enough amount of solder that the
> percentage
> of gold in the joint is relatively small and the problem is avoided.
>
> -- Tom, N5EG
>
>
>
>
> On Thu, Feb 22, 2018 at 12:29 PM, Leo Bodnar  wrote:
>
> > Here is ENIG fact that is not widely known at the moment but which some
> > might find useful.
> >
> > I could not understand why I get better TDR and insertion loss results
> > from solder-mask covered microstrip transmission lines than from
> otherwise
> > identical microstrips on the same substrate with soldermask removed and,
> > therefore, covered with ENIG.
> >
> > Gold can't be bad, right? As it turns out, even gold coin has two sides
> to
> > it.
> >
> > I have found that Shlepnev and McMorrow conducted extensive research and
> > published data, some of which is presented here
> http://www.simberian.com/
> > Presentations/NickelCharacterizationPresentation_emc2011.pdf
> >
> > In essence, it's not the "G" that is the problem - it is the "N".
> > Immersion Gold layer is not thick enough to contain whole of the skin
> > effect layer (even towards 100GHz) and as signal frequency increases most
> > of the signal ends up travelling through Nickel.
> > As Shlepnev commented "Nickel is the most mysterious metal in
> > electronics."  It has significant effect on insertion loss and risetime
> > degradation.  "Significant effect" is posh for "bad."
> >
> > Some mass PCB manufacturers have been known to apply ENIG before
> > soldermasking.  This causes even more high speed/frequency problems
> because
> > all of the copper on the outside layers will have Nickel over it -
> exposed
> > or not.
> >
> > Probably not a problem for majority of ENIG users but could cause a
> > headache or two for unsuspecting.
> >
> > Leo
> >
> > > Date: Thu, 22 Feb 2018 19:02:25 +
> > > From: Mark Sims 
> > >
> > > Yes, have the board done with ENIG gold.  It typically adds around $15
> > per run of boards.  I do all my boards with ENIG gold... if for no other
> > reason than the gold color makes it very easy to determine when your
> solder
> > paste properly covers the pads.
> > >
> > > And, as Charles mentioned,  the quality and thickness of the gold can
> > vary depending upon the board house.  I have used gojgo.com for a lot of
> > boards.  They do very good, quick work,  are well priced, and they seem
> to
> > have the best gold finish.
> > >
> > > Hard gold finish is VERY expensive these days.  I've been quoted $250+
> > for setup charges and per-board costs of over $25.
> >
> > ___
> > 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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[time-nuts] Teardown of Chinese made eBay GPS antenna.

[William H. Fite]

Ignore intellectual property rights - yes
Abusive labor practices - yes (I'm a radlib, this bothers me enormously)
Counterfeit parts - sometimes

But...

Little or no quality control - not necessarily
Drive out better goods - only if buyers allow to happen

Because...

The reason that Chinese manufacturers make and sell cheap crap is because
resellers (I'm looking at you, Americans and Europeans) specify the lowest
possible prices so they can make the highest possible profits.

The Chinese economy is strongly supply-side oriented. Simply put, they
build to the market, with little government regulation. If you go to China
and negotiate for top quality designs, parts, manufacturing processes, and
quality controls, they will happily build you products that match similar
items that come from Rohde & Schwarz or other top-notch manufacturers. That
said, if you want cheap, they'll certainly give you cheap.

When we want someone to blame for garbage in the marketplace, a good place
to look is in the mirror. China is not in the charity business; they build
what people want to buy.



On Thursday, February 22, 2018, djl  wrote:

> Fine. The Chinese have no concept of, or ignore, intellectual property
> rights. They will cheerfully use 13 year old girls to put together stuff
> using counterfeit parts and ripped circuits. There is little or no quality
> control. The problem is that these goods drive better goods out of the
> market.
>
>
> On 2018-02-22 14:39, William H. Fite wrote:
>
>> I wish people would lighten up on Chinese goods. Perhaps you are not aware
>> that China builds for and sells to both the DOD and NASA. Chinese
>> manufacturers build to the specs they are given. You want cheap crap,
>> they'll build cheap crap. You want top quality, they'll build top quality.
>>
>>
>> On Thursday, February 22, 2018, Van Horn, David <
>> david.vanh...@backcountryaccess.com> wrote:
>>
>> According to the data sheet, it looks pretty well in spec, and the part
>>> has thermal shutdown.
>>> http://ww1.microchip.com/downloads/en/DeviceDoc/mic5203.pdf
>>>
>>> ESD hit maybe?
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>>>
>>>
> --
> Dr. Don Latham
> PO Box 404, Frenchtown, MT, 59834
> VOX: 406-626-4304
>
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-- 
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when it deserves it.
--Mark Twain

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for sinners. His standards are quite low.
--Desmond Tutu
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Re: [time-nuts] Teardown of Chinese made eBay GPS antenna.

[Tom Van Baak]

Let's keep this thread on topic and highly informative.

Please treat time nuts as a technical mailing list, not social media.

Thanks,
/tvb
Moderator, www.leapsecond.com/time-nuts.htm

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Re: [time-nuts] Teardown of Chinese made eBay GPS antenna.

[djl]

Fine. The Chinese have no concept of, or ignore, intellectual property 
rights. They will cheerfully use 13 year old girls to put together stuff 
using counterfeit parts and ripped circuits. There is little or no 
quality control. The problem is that these goods drive better goods out 
of the market.



On 2018-02-22 14:39, William H. Fite wrote:
I wish people would lighten up on Chinese goods. Perhaps you are not 
aware

that China builds for and sells to both the DOD and NASA. Chinese
manufacturers build to the specs they are given. You want cheap crap,
they'll build cheap crap. You want top quality, they'll build top 
quality.



On Thursday, February 22, 2018, Van Horn, David <
david.vanh...@backcountryaccess.com> wrote:

According to the data sheet, it looks pretty well in spec, and the 
part

has thermal shutdown.
http://ww1.microchip.com/downloads/en/DeviceDoc/mic5203.pdf

ESD hit maybe?
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--
Dr. Don Latham
PO Box 404, Frenchtown, MT, 59834
VOX: 406-626-4304

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Re: [time-nuts] Teardown of Chinese made eBay GPS antenna.

[Clint Jay]

Then Africa.

On 22 Feb 2018 22:42, "Bob kb8tq"  wrote:

> India
>
> > On Feb 22, 2018, at 5:37 PM, Van Horn, David  backcountryaccess.com> wrote:
> >
> >
> > "Some  of you are to young to remember when Javanese products were
> considered junk same storyBert Kehren"
> >
> > I've lived through Japan, Taiwan, and now China.  Who's next?  
> >
> >
> >
> >
> > ___
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Re: [time-nuts] Teardown of Chinese made eBay GPS antenna.

[Bob kb8tq]

India

> On Feb 22, 2018, at 5:37 PM, Van Horn, David 
>  wrote:
> 
> 
> "Some  of you are to young to remember when Javanese products were considered 
> junk same storyBert Kehren"
> 
> I've lived through Japan, Taiwan, and now China.  Who's next?  
> 
> 
> 
> 
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Re: [time-nuts] Teardown of Chinese made eBay GPS antenna.

[Van Horn, David]

"Some  of you are to young to remember when Javanese products were considered 
junk same storyBert Kehren"

I've lived through Japan, Taiwan, and now China.  Who's next?  




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Re: [time-nuts] Teardown of Chinese made eBay GPS antenna.

[ewkehren via time-nuts]

Some  of you are to young to remember when Javanese products were considered 
junk same storyBert Kehren


Sent from my Galaxy Tab® A
 Original message From: "Van Horn, David" 
 Date: 2/22/18  4:44 PM  (GMT-05:00) To: 
Discussion of precise time and frequency measurement  
Subject: Re: [time-nuts] Teardown of Chinese made eBay GPS antenna. 
I wasn't making any comment about Chinese goods, just the component in question.

-Original Message-
From: time-nuts 
[mailto:time-nuts-bounces+david.vanhorn=backcountryaccess@febo.com] On 
Behalf Of William H. Fite
Sent: Thursday, February 22, 2018 2:40 PM
To: Discussion of precise time and frequency measurement 
Subject: Re: [time-nuts] Teardown of Chinese made eBay GPS antenna.

I wish people would lighten up on Chinese goods. Perhaps you are not aware that 
China builds for and sells to both the DOD and NASA. Chinese manufacturers 
build to the specs they are given. You want cheap crap, they'll build cheap 
crap. You want top quality, they'll build top quality.


On Thursday, February 22, 2018, Van Horn, David < 
david.vanh...@backcountryaccess.com> wrote:

> According to the data sheet, it looks pretty well in spec, and the 
> part has thermal shutdown.
> http://ww1.microchip.com/downloads/en/DeviceDoc/mic5203.pdf
>
> ESD hit maybe?
> ___
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--
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deserves it.
--Mark Twain

We may be surprised at the people we find in heaven. God has a soft spot for 
sinners. His standards are quite low.
--Desmond Tutu
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Re: [time-nuts] Teardown of Chinese made eBay GPS antenna.

[Bob kb8tq]

Hi

As mentioned in another post, the part does claim to have thermal limit
built in. They appear to pulse test them at 150 ma and 16V so there is
indeed *something* that would suggest operation at 12V would be ok. 
I’d guess that the thermal regulation spec applies up to 16V and past that
you are on your own…..

I’d take a look at the bypass caps on the regulator. Looking back at the 
original test data, it may have simply gone unstable at the higher voltage.
A 0.1 uf on the input and 0.47 uf on the output seem to be the minimums. 

Bob

> On Feb 22, 2018, at 2:48 PM, John Green  wrote:
> 
> For those who have been following the saga of the Chinese made, eBay
> purchased antenna that failed, I may have an answer as to why it failed.
> I had to destructively disassemble it. I just could not get it apart any
> other way. I used a Chinese version of a Dremel tool with a metal saw
> blade. After making a huge mess with plastic particles everywhere, it
> revealed a circular FR4 board with two patch antennas mounted, one atop the
> other. I assume the smaller one to be the L1, and the larger to be L2. This
> part looks almost identical to the Trimble Microcentered antenna I worked
> on recently. On the back side of this is a metal shield  about 3 by 3
> inches soldered to the circular FR4 board. I switched to a abrasive wheel
> and took off some of the solder holding the shield to the board. Then,
> using a small screw driver, I went around the shield breaking the solder
> loose. The shield off revealed that the coax goes to some capacitors that
> couple RF out and through an inductor with some capacitors to ground and
> finally to a SOT23-5 package labelled LK33. This appears to be a Micrel
> MIC5203 3.3 volt regulator. It is shorted on the input side. I believe that
> putting anything over 7.5 volts on the input exceeded the power dissipation
> rating and caused it to fail. I plan on wiring up a more robust 3.3 volt
> regulator in its place and trying again. It looks like I will be able to re
> solder the shield back. The watertight integrity is gone for good. I think
> I can find a plastic box I can mount it in so I can at least experiment
> with it. I have sent a message to the seller detailing my findings. The
> Micrel part lists a 20 volt maximum input voltage, so in theory at least,
> this might have worked, and there might be some of these out there that
> don't fail.
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Re: [time-nuts] Teardown of Chinese made eBay GPS antenna.

[Van Horn, David]

I wasn't making any comment about Chinese goods, just the component in question.

-Original Message-
From: time-nuts 
[mailto:time-nuts-bounces+david.vanhorn=backcountryaccess@febo.com] On 
Behalf Of William H. Fite
Sent: Thursday, February 22, 2018 2:40 PM
To: Discussion of precise time and frequency measurement 
Subject: Re: [time-nuts] Teardown of Chinese made eBay GPS antenna.

I wish people would lighten up on Chinese goods. Perhaps you are not aware that 
China builds for and sells to both the DOD and NASA. Chinese manufacturers 
build to the specs they are given. You want cheap crap, they'll build cheap 
crap. You want top quality, they'll build top quality.


On Thursday, February 22, 2018, Van Horn, David < 
david.vanh...@backcountryaccess.com> wrote:

> According to the data sheet, it looks pretty well in spec, and the 
> part has thermal shutdown.
> http://ww1.microchip.com/downloads/en/DeviceDoc/mic5203.pdf
>
> ESD hit maybe?
> ___
> 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.
>


--
Patriotism is supporting your country all the time, and your government when it 
deserves it.
--Mark Twain

We may be surprised at the people we find in heaven. God has a soft spot for 
sinners. His standards are quite low.
--Desmond Tutu
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Re: [time-nuts] Teardown of Chinese made eBay GPS antenna.

[William H. Fite]

I wish people would lighten up on Chinese goods. Perhaps you are not aware
that China builds for and sells to both the DOD and NASA. Chinese
manufacturers build to the specs they are given. You want cheap crap,
they'll build cheap crap. You want top quality, they'll build top quality.


On Thursday, February 22, 2018, Van Horn, David <
david.vanh...@backcountryaccess.com> wrote:

> According to the data sheet, it looks pretty well in spec, and the part
> has thermal shutdown.
> http://ww1.microchip.com/downloads/en/DeviceDoc/mic5203.pdf
>
> ESD hit maybe?
> ___
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> mailman/listinfo/time-nuts
> and follow the instructions there.
>


-- 
Patriotism is supporting your country all the time, and your government
when it deserves it.
--Mark Twain

We may be surprised at the people we find in heaven. God has a soft spot
for sinners. His standards are quite low.
--Desmond Tutu
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Re: [time-nuts] HP 5065A super

[Tom McDermott]

In general it's bad practice to gold plate SMT solder pads.  The reason is
that proper SMT soldering utilizes a very small amount of solder and the
gold plating
will partially dissolve into the molten solder. Because of the small amount
of
solder, the percentage of gold will be high enough to embrittle the solder
joint,
and it will have a high probability of failure.

Hand soldering can apply a large enough amount of solder that the percentage
of gold in the joint is relatively small and the problem is avoided.

-- Tom, N5EG




On Thu, Feb 22, 2018 at 12:29 PM, Leo Bodnar  wrote:

> Here is ENIG fact that is not widely known at the moment but which some
> might find useful.
>
> I could not understand why I get better TDR and insertion loss results
> from solder-mask covered microstrip transmission lines than from otherwise
> identical microstrips on the same substrate with soldermask removed and,
> therefore, covered with ENIG.
>
> Gold can't be bad, right? As it turns out, even gold coin has two sides to
> it.
>
> I have found that Shlepnev and McMorrow conducted extensive research and
> published data, some of which is presented here http://www.simberian.com/
> Presentations/NickelCharacterizationPresentation_emc2011.pdf
>
> In essence, it's not the "G" that is the problem - it is the "N".
> Immersion Gold layer is not thick enough to contain whole of the skin
> effect layer (even towards 100GHz) and as signal frequency increases most
> of the signal ends up travelling through Nickel.
> As Shlepnev commented "Nickel is the most mysterious metal in
> electronics."  It has significant effect on insertion loss and risetime
> degradation.  "Significant effect" is posh for "bad."
>
> Some mass PCB manufacturers have been known to apply ENIG before
> soldermasking.  This causes even more high speed/frequency problems because
> all of the copper on the outside layers will have Nickel over it - exposed
> or not.
>
> Probably not a problem for majority of ENIG users but could cause a
> headache or two for unsuspecting.
>
> Leo
>
> > Date: Thu, 22 Feb 2018 19:02:25 +
> > From: Mark Sims 
> >
> > Yes, have the board done with ENIG gold.  It typically adds around $15
> per run of boards.  I do all my boards with ENIG gold... if for no other
> reason than the gold color makes it very easy to determine when your solder
> paste properly covers the pads.
> >
> > And, as Charles mentioned,  the quality and thickness of the gold can
> vary depending upon the board house.  I have used gojgo.com for a lot of
> boards.  They do very good, quick work,  are well priced, and they seem to
> have the best gold finish.
> >
> > Hard gold finish is VERY expensive these days.  I've been quoted $250+
> for setup charges and per-board costs of over $25.
>
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Re: [time-nuts] Teardown of Chinese made eBay GPS antenna.

[Van Horn, David]

According to the data sheet, it looks pretty well in spec, and the part has 
thermal shutdown.
http://ww1.microchip.com/downloads/en/DeviceDoc/mic5203.pdf

ESD hit maybe?
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Re: [time-nuts] Teardown of Chinese made eBay GPS antenna.

[djl]

 Chinese made, ... This
part looks almost identical to the Trimble Microcentered antenna I 
worked

on recently.


Right. It's Chinese made. 'nuff said.

Don

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--
Dr. Don Latham
PO Box 404, Frenchtown, MT, 59834
VOX: 406-626-4304

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[time-nuts] Teardown of Chinese made eBay GPS antenna.

[John Green]

For those who have been following the saga of the Chinese made, eBay
purchased antenna that failed, I may have an answer as to why it failed.
I had to destructively disassemble it. I just could not get it apart any
other way. I used a Chinese version of a Dremel tool with a metal saw
blade. After making a huge mess with plastic particles everywhere, it
revealed a circular FR4 board with two patch antennas mounted, one atop the
other. I assume the smaller one to be the L1, and the larger to be L2. This
part looks almost identical to the Trimble Microcentered antenna I worked
on recently. On the back side of this is a metal shield  about 3 by 3
inches soldered to the circular FR4 board. I switched to a abrasive wheel
and took off some of the solder holding the shield to the board. Then,
using a small screw driver, I went around the shield breaking the solder
loose. The shield off revealed that the coax goes to some capacitors that
couple RF out and through an inductor with some capacitors to ground and
finally to a SOT23-5 package labelled LK33. This appears to be a Micrel
MIC5203 3.3 volt regulator. It is shorted on the input side. I believe that
putting anything over 7.5 volts on the input exceeded the power dissipation
rating and caused it to fail. I plan on wiring up a more robust 3.3 volt
regulator in its place and trying again. It looks like I will be able to re
solder the shield back. The watertight integrity is gone for good. I think
I can find a plastic box I can mount it in so I can at least experiment
with it. I have sent a message to the seller detailing my findings. The
Micrel part lists a 20 volt maximum input voltage, so in theory at least,
this might have worked, and there might be some of these out there that
don't fail.
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Re: [time-nuts] HP 5065A super

[Leo Bodnar]

Here is ENIG fact that is not widely known at the moment but which some might 
find useful.

I could not understand why I get better TDR and insertion loss results from 
solder-mask covered microstrip transmission lines than from otherwise identical 
microstrips on the same substrate with soldermask removed and, therefore, 
covered with ENIG.

Gold can't be bad, right? As it turns out, even gold coin has two sides to it.

I have found that Shlepnev and McMorrow conducted extensive research and 
published data, some of which is presented here 
http://www.simberian.com/Presentations/NickelCharacterizationPresentation_emc2011.pdf

In essence, it's not the "G" that is the problem - it is the "N".
Immersion Gold layer is not thick enough to contain whole of the skin effect 
layer (even towards 100GHz) and as signal frequency increases most of the 
signal ends up travelling through Nickel.  
As Shlepnev commented "Nickel is the most mysterious metal in electronics."  It 
has significant effect on insertion loss and risetime degradation.  
"Significant effect" is posh for "bad."

Some mass PCB manufacturers have been known to apply ENIG before soldermasking. 
 This causes even more high speed/frequency problems because all of the copper 
on the outside layers will have Nickel over it - exposed or not.

Probably not a problem for majority of ENIG users but could cause a headache or 
two for unsuspecting.

Leo

> Date: Thu, 22 Feb 2018 19:02:25 +
> From: Mark Sims 
> 
> Yes, have the board done with ENIG gold.  It typically adds around $15 per 
> run of boards.  I do all my boards with ENIG gold... if for no other reason 
> than the gold color makes it very easy to determine when your solder paste 
> properly covers the pads.
> 
> And, as Charles mentioned,  the quality and thickness of the gold can vary 
> depending upon the board house.  I have used gojgo.com for a lot of boards.  
> They do very good, quick work,  are well priced, and they seem to have the 
> best gold finish.
> 
> Hard gold finish is VERY expensive these days.  I've been quoted $250+ for 
> setup charges and per-board costs of over $25.  

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[time-nuts] HP 5065A super

[Mark Sims]

Yes, have the board done with ENIG gold.  It typically adds around $15 per run 
of boards.  I do all my boards with ENIG gold... if for no other reason than 
the gold color makes it very easy to determine when your solder paste properly 
covers the pads.

And, as Charles mentioned,  the quality and thickness of the gold can vary 
depending upon the board house.  I have used gojgo.com for a lot of boards.  
They do very good, quick work,  are well priced, and they seem to have the best 
gold finish.

Hard gold finish is VERY expensive these days.  I've been quoted $250+ for 
setup charges and per-board costs of over $25.  
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Re: [time-nuts] HP 5065A super

[Attila Kinali]

On Thu, 22 Feb 2018 15:33:50 +
"Poul-Henning Kamp"  wrote:

> >Then i would go for the LTC6240HV with a +/-5V power supply.
> 
> Offset voltage (stability) is a, if not the, *very* important
> parameter for the integrator.

That's another reason to choose the LTC6240 over the LT1793.
Beside the smaller 1/f noise (0.55µVpp vs 2.4µVpp), the LTC6240
has a much lower temperature coefficient (0.7µV/°C vs 8µV/°C).

The biggest drawback of the LT6240HV is its limited input range
of -5V to +3V (for a +/-5V supply). But in an integrator application,
this shouldn't be a problem (phase reversal is prevented by the 10k
input resistor). 


Attila Kinali

-- 
It is upon moral qualities that a society is ultimately founded. All 
the prosperity and technological sophistication in the world is of no 
use without that foundation.
 -- Miss Matheson, The Diamond Age, Neil Stephenson
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Re: [time-nuts] HP 5065A super

[Poul-Henning Kamp]

In message <20180222160256.68d832a88fc2d7da91602...@kinali.ch>, Attila Kinali w
rites:

>Ah.. this looks significantly different than my 5065 service manual shows.
>
>So, I guess you want to build a new board that replaces this?
>
>Then i would go for the LTC6240HV with a +/-5V power supply.

Offset voltage (stability) is a, if not the, *very* important
parameter for the integrator.

-- 
Poul-Henning Kamp   | UNIX since Zilog Zeus 3.20
p...@freebsd.org | TCP/IP since RFC 956
FreeBSD committer   | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by incompetence.
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Re: [time-nuts] HP 5065A super

[Attila Kinali]

On Thu, 22 Feb 2018 09:24:53 -0500
ew via time-nuts  wrote:

> Attached the schematic of the A9 my file of the picture is to large it is the
> integrator. 

Ah.. this looks significantly different than my 5065 service manual shows.

So, I guess you want to build a new board that replaces this?

Then i would go for the LTC6240HV with a +/-5V power supply.
I agree with Charles that you want to have low noise power supplies,
though I think using a much cheaper and easier to solder TPS7A49
together with an TPS7A3001 should be more than enough, considering
that the LTC6240HV has a PSRR of >80dB.

If you need more than +/-5V range for the EFC, I'd add an
LTC2057 or LT6018 as amplifier stage after the integrator,
powered from +/-15V.

An alternative design would be to use a discrete JFET/MOSFET
input stage together with an LT6018. But you'd need to select
your FET carefully, as it then would limit your 1/f noise and
determine your leakage current.

Attila Kinali
-- 
It is upon moral qualities that a society is ultimately founded. All 
the prosperity and technological sophistication in the world is of no 
use without that foundation.
 -- Miss Matheson, The Diamond Age, Neil Stephenson
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Re: [time-nuts] Curious, how many t-nuts have 5065A

[ewkehren via time-nuts]

Do not know but it is the holy grail of AV nuts short of a Maser  or 8607Bert 
Kehren


Sent from my Galaxy Tab® A
 Original message From: Pete Lancashire 
 Date: 2/22/18  9:44 AM  (GMT-05:00) To: Discussion of 
precise time and frequency measurement  Subject: 
[time-nuts] Curious, how many t-nuts have 5065A 
no reason other then  curious

-pete
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Re: [time-nuts] read of the wire - the Clock of the Long Now

[paul swed]

Pete,
Any updates from your doctor?
Regards
Paul

On Thu, Feb 22, 2018 at 9:18 AM, Pete Lancashire 
wrote:

> https://www.theengineer.co.uk/1-year-clock-texan-mountain/
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[time-nuts] Curious, how many t-nuts have 5065A

[Pete Lancashire]

no reason other then  curious

-pete
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Re: [time-nuts] HP 5065A super

[Bob kb8tq]

Hi

The control loop (of which A9 is a part) ultimately locks the OCXO in the 5065 
to the Rb 
transition. Gain in the control loop suppresses the noise of the OCXO, making 
it’s ADEV
better than it would have been stand alone. 

Ok so far? Bob’s not off the tracks (yet)? 

The various processes that create ADEV (or whatever you want to call it) on the 
OCXO 
could be translated back to an “equivalent EFC noise” number at various 
frequencies. 
More or less, assume an ideal OCXO and blame all the problems on some little 
noise
source in series with the EFC line. Very much like blaming all the noise in an 
op amp on
the input stage. 

Still ok (if a bit unconventional) ? 

At this point one should be able to sum the magic EFC noise with op amp noise 
or whatever
else you are worried about and compare their magnitudes. If one is 1/100th of 
the other 
then maybe it’s not the thing to worry about. Yes, you could carry it on 
through the various 
control loop equations and get things even more correct. 

No, I haven’t done all of this, but it seems to be a way to come up with a 
fairly detailed answer
to “what’s good enough” in the control loop, 

Bob

> On Feb 22, 2018, at 9:04 AM, Charles Steinmetz  wrote:
> 
>> Ais the LT1793 the best choice the time constant is 0.05 seconds with a 
>> 10 K resistor and 5 uF Capacitor
>> Bshould we add resistors and decoupling on the + - 15 volt op amp 
>> supplies
>> CGold plating the edge connecter,  does any one know a reasonable 
>> source, or is doing it at home an option and if yes, how best way to do so.
> 
> A.  The 1793 is a good choice.  You should look at the LT1012 also.  The 
> headlines on the 1793 datasheet suggest it is significantly quieter than the 
> 1012.  HOWEVER: you are particularly interested in frequencies well below 
> 10Hz, and due to an extremely low 1/f noise corner, the 1012 is actually 5x 
> quieter than the 1793 between 0.1 and 10 Hz (0.5uV for the 1012 p-p vs. 2.4uV 
> p-p for the 1793).  The 1012 can also be overcompensated, which could be a 
> significant advantage in this application.  [Note that the 1793 has lower 
> input current noise than the 1012, but that is irrelevant in the HP circuit 
> because of the relatively low impedances at the op-amp inputs.  Because of 
> that, the input voltage noise dominates the total noise.]
> 
> B.  If you do this, the decoupling has to be good down through at least 
> milliHz, maybe even microHz.  That would require capacitors in the 1F range 
> with suitable decoupling resistors (100 ohms or below).  The op amp is fed by 
> dedicated +/- regulators, so you'll get the best result by just using the 
> lowest-noise regulators available.  That means the LT3042 for V+.  You will 
> have to pore through datasheets to find the lowest-noise negative regulator 
> available today (as above, paying particular attention to the noise specs 
> below 1Hz).
> 
> C.  You normally just tell the board house to plate the edge fingers. It is 
> not outrageously expensive.  OR, here is another, heretical suggestion:  I 
> have designed a number of plug-in daughterboards using ENIG finish on the 
> whole board, including the edge fingers.  *NOTE* this is an "off-label" use 
> of ENIG finish.  The board house I used for the first batch of ENIG-plated 
> fingers (ITEAD Studio) gave me very robust plating, so I have continued to 
> use them for boards with ENIG-plated edge fingers.
> 
> I tested a number of the cards over more than 100 insertion-removal cycles, 
> and viewed under magnification there was very little wear and absolutely no 
> nickel or copper showing ("ENIG" stands for "electroless nickel immersion 
> gold," meaning the copper is coated first with nickle and then with gold.  
> The boards I've tested have not worn through the gold even after >100 
> insertion-removal cycles -- way, way more than any plug-in board is likely 
> ever to see.)
> 
> *NB:*  ENIG plating varies widely from one board house to another, and very 
> likely varies somewhat from one batch to another at any particular board 
> house, so YMMV!!!  I've done a dozen or so projects with ENIG-plated fingers 
> using ITEAD Studio, and have been very pleased with the results each time.
> 
> Charles
> 
> 
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Re: [time-nuts] HP 5065A super

[ew via time-nuts]

Attached the schematic of the A9 my file of the picture is to large it is the 
integrator. I just gave Corby my extra A12  RVFR that at one time I was going 
to do something along the way you suggested but age and the number of projects 
on our list have ought up with reality. Remember when you visited us you got an 
idea of what we are working on and what has been completed.LED Laser pumping 
was on our list, we have some ideas and have kicked them around off list. 
Decided to focus on 5065A
On a related subject long term tests on my HP 5061B with the new tube  show 
better than 1E-13 my plan is to discipline the 5065A with it using the 600 
second Wenzel circuit. Laying out a new board and have Corby compare it against 
his Maser.
We have a temperature and pressure board for FRK and M100 but I do not think it 
will be needed with 600 seconds.
Bert Kehren
 
In a message dated 2/22/2018 8:55:22 AM Eastern Standard Time, att...@kinali.ch 
writes:

 
 On Thu, 22 Feb 2018 07:00:54 -0500
ew via time-nuts  wrote:

> Now a step by step work over, including HP mods for later  units like 
> replacing the 74196’s in the synthesizer module with 74LS196. May have been 
> end of life of the 74196.

With some slight change of the circuit, you should be able to replace
the 74196 by an 74163 which is available as LVC and thus should be
around for the next 10-20 years at least.

> Now to the purpose of this post. The A9 module is after 88 a significant 
> change and Corby sees an improvement against his Maser. We are doing a board 
> and maybe some other will be interested.

What does the A9 module do, for those of us who have not learned the inner
workings of the 5065 by heart? "Integrator Assembly" doesn't say too much

> Here are the issues
> A    is the LT1793 the best choice the time constant is 0.05 seconds with a 
> 10 K resistor and 5 uF Capacitor

What are your constraints? For every single parameter, there is an opamp
that beats the LT1793.
Do you just want to replace the opamp on A9 or build a new A9 from scratch?
If you can live with a power supply <12V, then I'd go for the LTC6240HV.

> B    should we add resistors and decoupling on the + - 15 volt op amp supplies

Depends on the noise of the power supply. My experience is, that resistors
in the power path causes more trouble than not having them. Though, I highly
suspect those were mostly caused by improper design. If you have problem with
noise on the power supply, I would rather suggest to use some low noise
LDOs instead. The TPS7Axx family from TI has quite a few offerings of
suitable LDOs. They are not on par with the LT3042, but they beat anything
you will have in 5065. And they are easier to solder :-)


> C    Gold plating the edge connecter,  does any one know a reasonable source, 
> or is doing it at home an option and if yes, how best way to do so.

There are gold plating solutions available, if you want to do it at home.
Though I would suggest to choose a PCB manufacturer that offers it.
In europe, i'd recommend Eurocircuits, but i'm pretty sure you have a
similarly cheap shop in the US. There are probably some shops in China
that offer that as well. Mind you, gold plating will increase the PCB
cost considerably, as it's a non-standard process. Not to mention that
you need hard gold for connector contacts, which is different from the
standard gold plating you will get as surface finish.


 Attila Kinali
-- 
It is upon moral qualities that a society is ultimately founded. All 
the prosperity and technological sophistication in the world is of no 
use without that foundation.
 -- Miss Matheson, The Diamond Age, Neil Stephenson
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[time-nuts] read of the wire - the Clock of the Long Now

[Pete Lancashire]

https://www.theengineer.co.uk/1-year-clock-texan-mountain/
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Re: [time-nuts] HP 5065A super

[Charles Steinmetz]

Ais the LT1793 the best choice the time constant is 0.05 seconds with a 10 
K resistor and 5 uF Capacitor
Bshould we add resistors and decoupling on the + - 15 volt op amp supplies
CGold plating the edge connecter,  does any one know a reasonable source, 
or is doing it at home an option and if yes, how best way to do so.


A.  The 1793 is a good choice.  You should look at the LT1012 also.  The 
headlines on the 1793 datasheet suggest it is significantly quieter than 
the 1012.  HOWEVER: you are particularly interested in frequencies well 
below 10Hz, and due to an extremely low 1/f noise corner, the 1012 is 
actually 5x quieter than the 1793 between 0.1 and 10 Hz (0.5uV for the 
1012 p-p vs. 2.4uV p-p for the 1793).  The 1012 can also be 
overcompensated, which could be a significant advantage in this 
application.  [Note that the 1793 has lower input current noise than the 
1012, but that is irrelevant in the HP circuit because of the relatively 
low impedances at the op-amp inputs.  Because of that, the input voltage 
noise dominates the total noise.]


B.  If you do this, the decoupling has to be good down through at least 
milliHz, maybe even microHz.  That would require capacitors in the 1F 
range with suitable decoupling resistors (100 ohms or below).  The op 
amp is fed by dedicated +/- regulators, so you'll get the best result by 
just using the lowest-noise regulators available.  That means the LT3042 
for V+.  You will have to pore through datasheets to find the 
lowest-noise negative regulator available today (as above, paying 
particular attention to the noise specs below 1Hz).


C.  You normally just tell the board house to plate the edge fingers. 
It is not outrageously expensive.  OR, here is another, heretical 
suggestion:  I have designed a number of plug-in daughterboards using 
ENIG finish on the whole board, including the edge fingers.  *NOTE* this 
is an "off-label" use of ENIG finish.  The board house I used for the 
first batch of ENIG-plated fingers (ITEAD Studio) gave me very robust 
plating, so I have continued to use them for boards with ENIG-plated 
edge fingers.


I tested a number of the cards over more than 100 insertion-removal 
cycles, and viewed under magnification there was very little wear and 
absolutely no nickel or copper showing ("ENIG" stands for "electroless 
nickel immersion gold," meaning the copper is coated first with nickle 
and then with gold.  The boards I've tested have not worn through the 
gold even after >100 insertion-removal cycles -- way, way more than any 
plug-in board is likely ever to see.)


*NB:*  ENIG plating varies widely from one board house to another, and 
very likely varies somewhat from one batch to another at any particular 
board house, so YMMV!!!  I've done a dozen or so projects with 
ENIG-plated fingers using ITEAD Studio, and have been very pleased with 
the results each time.


Charles


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Re: [time-nuts] HP 5065A super

[Attila Kinali]

On Thu, 22 Feb 2018 07:00:54 -0500
ew via time-nuts  wrote:

> Now a step by step work over, including HP mods for later  units like 
> replacing the 74196’s in the synthesizer module with 74LS196. May have been 
> end of life of the 74196.

With some slight change of the circuit, you should be able to replace
the 74196 by an 74163 which is available as LVC and thus should be
around for the next 10-20 years at least.

> Now to the purpose of this post. The A9 module is after 88 a significant 
> change and Corby sees an improvement against his Maser. We are doing a board 
> and maybe some other will be interested.

What does the A9 module do, for those of us who have not learned the inner
workings of the 5065 by heart? "Integrator Assembly" doesn't say too much

> Here are the issues
> A    is the LT1793 the best choice the time constant is 0.05 seconds with a 
> 10 K resistor and 5 uF Capacitor

What are your constraints? For every single parameter, there is an opamp
that beats the LT1793.
Do you just want to replace the opamp on A9 or build a new A9 from scratch?
If you can live with a power supply <12V, then I'd go for the LTC6240HV.

> B    should we add resistors and decoupling on the + - 15 volt op amp supplies

Depends on the noise of the power supply. My experience is, that resistors
in the power path causes more trouble than not having them. Though, I highly
suspect those were mostly caused by improper design. If you have problem with
noise on the power supply, I would rather suggest to use some low noise
LDOs instead. The TPS7Axx family from TI has quite a few offerings of
suitable LDOs. They are not on par with the LT3042, but they beat anything
you will have in 5065. And they are easier to solder :-)


> C    Gold plating the edge connecter,  does any one know a reasonable source, 
> or is doing it at home an option and if yes, how best way to do so.

There are gold plating solutions available, if you want to do it at home.
Though I would suggest to choose a PCB manufacturer that offers it.
In europe, i'd recommend Eurocircuits, but i'm pretty sure you have a
similarly cheap shop in the US. There are probably some shops in China
that offer that as well. Mind you, gold plating will increase the PCB
cost considerably, as it's a non-standard process. Not to mention that
you need hard gold for connector contacts, which is different from the
standard gold plating you will get as surface finish.


Attila Kinali
-- 
It is upon moral qualities that a society is ultimately founded. All 
the prosperity and technological sophistication in the world is of no 
use without that foundation.
 -- Miss Matheson, The Diamond Age, Neil Stephenson
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Re: [time-nuts] LED instead of discharge lamp for Rb vapor cell standards

[Bob kb8tq]

Hi


> On Feb 22, 2018, at 8:22 AM, Attila Kinali  wrote:
> 
> On Wed, 21 Feb 2018 18:10:17 +
> "Poul-Henning Kamp"  wrote:
> 
>>> So the Rb85 "notch" filter might not get rid of all the unwanted light
>>> and some of this might depopulate the excited state of the Rb87
>>> that are in the RF cavity.
>> 
>> I have a hard time seeing how you can not get worse S/N that way.
> 
> 
> Well, the question is how much? Keep in mind that an Rb lamp is
> anything but a clean light source. 

The point is that it’s clean where it matters. It does not dump a bunch of
energy into the transitions that you want to avoid.

Bob

> 
>> If you want to do it with a LED, I think it needs to be a stabilized
>> LED-Laser.
> 
> The problem with a Laser is that you need to lock it to the
> right line. This requires either some significant change to the
> electronics of the Rb standard, or an additional vapor cell and
> some optics to lock it to that cell. Neither is trivial (apparently,
> according to the papers I've read, not difficult, but I don't trust
> that until I have tried myself).
> 
>   Attila Kinali
> 
> -- 
> It is upon moral qualities that a society is ultimately founded. All 
> the prosperity and technological sophistication in the world is of no 
> use without that foundation.
> -- Miss Matheson, The Diamond Age, Neil Stephenson
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Re: [time-nuts] LED instead of discharge lamp for Rb vapor cell standards

[Attila Kinali]

On Wed, 21 Feb 2018 18:10:17 +
"Poul-Henning Kamp"  wrote:

> >So the Rb85 "notch" filter might not get rid of all the unwanted light
> >and some of this might depopulate the excited state of the Rb87
> >that are in the RF cavity.
> 
> I have a hard time seeing how you can not get worse S/N that way.


Well, the question is how much? Keep in mind that an Rb lamp is
anything but a clean light source. 

> If you want to do it with a LED, I think it needs to be a stabilized
> LED-Laser.

The problem with a Laser is that you need to lock it to the
right line. This requires either some significant change to the
electronics of the Rb standard, or an additional vapor cell and
some optics to lock it to that cell. Neither is trivial (apparently,
according to the papers I've read, not difficult, but I don't trust
that until I have tried myself).

Attila Kinali

-- 
It is upon moral qualities that a society is ultimately founded. All 
the prosperity and technological sophistication in the world is of no 
use without that foundation.
 -- Miss Matheson, The Diamond Age, Neil Stephenson
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[time-nuts] HP 5065A super

[ew via time-nuts]

In December I lucked out buying a HP5065A for a very reasonable price, as is 
not tested. Turns out it was not working and I was not able to fix it. Corby to 
the rescue. Corby and I have shared many projects over the past, go back over 
15 years, as a matter of fact he introduced me to time-nuts. Took Corbe over a 
week to find the problem, a defective Rb87 reference cell. Never seen before, 
no crack visible but obviously no Rb87. Corby had a replacement and the result 
is that it is the third best 5065A he has ever worked with. The logical choice 
is the super conversion. Not dramatic improvement because it was already very 
good.
Now a step by step work over, including HP mods for later  units like replacing 
the 74196’s in the synthesizer module with 74LS196. May have been end of life 
of the 74196.
Now to the purpose of this post. The A9 module is after 88 a significant change 
and Corby sees an improvement against his Maser. We are doing a board and maybe 
some other will be interested.
Here are the issues
A    is the LT1793 the best choice the time constant is 0.05 seconds with a 10 
K resistor and 5 uF Capacitor
B    should we add resistors and decoupling on the + - 15 volt op amp supplies
C    Gold plating the edge connecter,  does any one know a reasonable source, 
or is doing it at home an option and if yes, how best way to do so.
Bert Kehren
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