[time-nuts] temperature stability basics

[beale]

In an attempt to educate myself about temperature stability, I put a 
temperature sensor in a 1" cube of brass wrapped in plastic packing-type bubble 
wrap, and compared that with another sensor outside the bubble wrap, with the 
whole combination in a thin nylon case just to slow down direct air drafts. I 
put it on the bench in the office where the ambient temperature varies up and 
down by a few degrees over the day. I recorded both temperatures with 
milli-degree resolution.

Looking at the resulting plots, it looks like my thermal mass and thermal 
insulation on the "inside" sensor gives me only about a half  hour lag at most 
relative to the "outside" sensor (hard to say exactly, it doesn't look like a 
simple one-pole filter). Note, I am not attempting any kind of ovenized control 
as yet, just measuring some time constants.

I've read that plain bubble wrap has an "R value" of about 2 
ft^2·°F·h/(BTU·in), while some types of rigid foam building insulation go up to 
R=8 (at least until the CFC gases used to blow the foam leak out). What is done 
in real instruments that need good thermal insulation? I assume dewar flasks 
are limited to aerospace applications.

Photo of the block prior to bubble wrap:
http://picasaweb.google.com/bealevideo/2010_11_18TempExperiment

(live) plot of temperatures:
http://www.pachube.com/feeds/12988

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[time-nuts] ok, newbie questions

[W2HX]

Hi all, I am sure my questions have been asked before. Unfortunately, the
mailman style archives are so hard to search through. So forgive me my
transgressions. Happy will I be to get a reference to an old thread that
answers my questions. Don't need new answers if old ones suffice. (of course
new answers always welcome!)

I am looking for a 10 MHz standard for my lab.  Accuracy/stability probably
wouldn't make a hill of beans difference in the stuff I do, so my questions
are more academic and it's just nice knowing I have a "really good"
standard.

1. So from reading about this topic on KE5FX.com I understand that a better
ocxo makes for better phase noise and near-term quality.  I also understand
that some later tbolts had a very good ocxo in them and therefore would not
benefit significantly from an upgrade as ke5fx did using an HP 10811 unit.
I am considering a thunderbolt advertised on ebay by "flyingbest." I will be
traveling to China (mainland, and Hong Kong) on business the last two weeks
in December so I might save some shipping.  Here is a photo. Can anyone tell
me if this unit has a  "better" 10811-class ocxo or "not so good "ocxo? I
also understand that not all ocxo's are created equal, even if they are the
same model number.

http://tinyurl.com/2dg2dz3

2. Other GPS DO units seem to differ on the number of satellites they can
receive from simultaneously (channels). What is the net effect of having a
standard that can see 6,8 or 16 birds? Is noise averaged out? Is
stability/phase noise improved? Here is an example of a 16 sat unit.  Anyone
have any experience with this unit? Good/bad indifferent? It seems they can
be had for about $200.

http://tinyurl.com/2ad5kls

3. And then there is the venerable HP units like this one.  I understand
this uses the 10811 ocxo. Other than the better ocxo, is there anything
inherently superior about these HP units to warrant the additional cost? Or
are we mostly just paying for the HP name?  This one is 6 sats.

http://tinyurl.com/24tkwdv

Lastly, my use of a 10 MHz standard will be for use in equipment like
microwave counters (EIP 548A), Spectrum analyzers (HP 8658B) VNA's (HP
3577A, 8753C to 6 GHz), synthesizer (HP 3326A and HP 8662A), premium
receivers (Harris 590H), etc., etc. For these purposes, is a GPS DO advised,
or perhaps a rubidium standard? For example, I don't need this to power a
clock. Just a good, clean, stable signal with low noise, low spurs, etc.

What's the overall opinion? THANKS 

(here's to hoping this message looks better than the first two tests I made)
73 Eugene W2HX





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Re: [time-nuts] First post - please disregard yet again

[Mike Feher]

BTW - I have some of those Thunderbolts as well as the T-30B power supplies
if that is what you are looking for - Mike

Mike B. Feher, EOZ Inc.
89 Arnold Blvd.
Howell, NJ, 07731
732-886-5960 office
908-901-9193 cell


-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of W2HX
Sent: Thursday, November 25, 2010 11:17 PM
To: 'Discussion of precise time and frequency measurement'
Subject: Re: [time-nuts] First post - please disregard yet again

Yikes. That didn't look so good. One last attempt to enclose the url in
chevrons <>. If that doesn't work, I'll resort to tinyurl.




73 Eugene W2HX

-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of W2HX
Sent: Thursday, November 25, 2010 11:12 PM
To: time-nuts@febo.com
Subject: [time-nuts] First post - please disregard

Getting ready to make a post and wanted to see if this list supports html or
only plain text and to see how urls are handled. (trying to avoid a mess of
a first post)

 

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem
 &item=270515147719&ssPageName=STRK:MEWAX:IT

 

 

73 Eugene W2HX

 

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Re: [time-nuts] First post - please disregard

[Mike Feher]

Go for it Gene - 73 - Mike

Mike B. Feher, EOZ Inc.
89 Arnold Blvd.
Howell, NJ, 07731
732-886-5960 office
908-901-9193 cell


-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of W2HX
Sent: Thursday, November 25, 2010 11:12 PM
To: time-nuts@febo.com
Subject: [time-nuts] First post - please disregard

Getting ready to make a post and wanted to see if this list supports html or
only plain text and to see how urls are handled. (trying to avoid a mess of
a first post)

 

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem
 &item=270515147719&ssPageName=STRK:MEWAX:IT

 

 

73 Eugene W2HX

 

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Re: [time-nuts] First post - please disregard yet again

[W2HX]

Yikes. That didn't look so good. One last attempt to enclose the url in
chevrons <>. If that doesn't work, I'll resort to tinyurl.




73 Eugene W2HX

-Original Message-
From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On
Behalf Of W2HX
Sent: Thursday, November 25, 2010 11:12 PM
To: time-nuts@febo.com
Subject: [time-nuts] First post - please disregard

Getting ready to make a post and wanted to see if this list supports html or
only plain text and to see how urls are handled. (trying to avoid a mess of
a first post)

 

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem
 &item=270515147719&ssPageName=STRK:MEWAX:IT

 

 

73 Eugene W2HX

 

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[time-nuts] First post - please disregard

[W2HX]

Getting ready to make a post and wanted to see if this list supports html or
only plain text and to see how urls are handled. (trying to avoid a mess of
a first post)

 

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem
 &item=270515147719&ssPageName=STRK:MEWAX:IT

 

 

73 Eugene W2HX

 

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Re: [time-nuts] Plastic covered OCXOs

[Bruce Griffiths]

Try:

http://www.rakon.com/Products/Public%20Documents/Specifications/RFPO40.pdf 
??

A link to this is on Rakon's website home page.

Bruce

Robert Darlington wrote:

Got a URL handy?  I'm interested in looking at a data sheet or two but
couldn't find anything with Google.

-Bob

On Thu, Nov 25, 2010 at 4:33 PM, Murray Greenman
wrote:

   

I could tell you but...

There's a lot of interesting IP in these little guys!

Regards,
Murray Greenman
RAKON


 



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Re: [time-nuts] Plastic covered OCXOs

[Robert Darlington]

Got a URL handy?  I'm interested in looking at a data sheet or two but
couldn't find anything with Google.

-Bob

On Thu, Nov 25, 2010 at 4:33 PM, Murray Greenman
wrote:

> I could tell you but...
>
> There's a lot of interesting IP in these little guys!
>
> Regards,
> Murray Greenman
> RAKON
>
>
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Re: [time-nuts] Plastic covered OCXOs

[Bob Camp]

Hi

Who could possibly be listening in on a list like this?

Bob

Vectron


On Nov 25, 2010, at 6:33 PM, Murray Greenman wrote:

> I could tell you but...
> 
> There's a lot of interesting IP in these little guys!
> 
> Regards,
> Murray Greenman
> RAKON
> 
> 
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[time-nuts] Plastic covered OCXOs

[Murray Greenman]

I could tell you but...

There's a lot of interesting IP in these little guys!

Regards,
Murray Greenman
RAKON


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Re: [time-nuts] GPS simulator,

[Bob Camp]

Hi

It's not real clear that they do anything more than sample the RX and play it 
back for the TX. 

Bob

Sent from my iPhone

On Nov 25, 2010, at 9:39 AM, "J. Forster"  wrote:

> Agreed. The trick is to properly partition what is done in hardware ane
> what is done in software. This could eliminate a lot of logic hardware.
> 
> Clearly, the RF stuff and modulator are hardware.
> Ditto PR code generation.
> Everything else in SW, I think.
> 
> FWIW,
> 
> -John
> 
> ===
> 
> 
>> Hi
>> 
>> One bit serial at 16 MHz isn't all that fancy any more. Sounds like a
>> shift register feeding a couple filters.
>> 
>> The money must be in the receive side.
>> 
>> Bob
>> 
>> On Nov 24, 2010, at 5:14 PM, erniepe...@aol.com wrote:
>> 
>>> 
>>> 
>>> 
>>> Hi,
>>> 
>>>  found an interesting unit. I think it is not for the usual pocket
>>> money for a time-nuts.
>>>  have a look...
>>> 
>>>  http://www.chronos.co.uk/pdfs/rac/labsat.pdf
>>> 
>>> Rgds Ernie.
>>> 
>>> 
>>> 
>>> 
>>> 
>>> 
>>> 
>>> 
>>> 
>>> -Original Message-
>>> From: John Green 
>>> To: time-nuts@febo.com
>>> Sent: Mon, Nov 22, 2010 6:43 pm
>>> Subject: [time-nuts] GPS jamming susceptibility
>>> 
>>> 
>>> Given that this is an extremely sensitive topic and completely illegal
>>> lso, let me just state at the outset that I have no interest in
>>> amming anyone's GPS. A while back, I was looking at one of those
>>> hinese discount electronics websites, I'm sure we all have, and
>>> oticed a GPS jammer for sale. I had been wanting to do some jamming
>>> usceptibility testing for quite some time but had never got around to
>>> uilding a generator to test with. The thing was cheap so I ordered
>>> t. After it arrived, I opened it up, first thing, to see how it was
>>> ade. It has a dual 555 oscillator, a couple of analog switches, a 1.9
>>> Hz VCO, a single amplifier. It doesn't look capable of putting out
>>> ore than 50 milliwatts or so into a 2 inch antenna. I was somewhat
>>> ubious that it would do anything, so I took it to the bench where the
>>> 3801 lives and turned it on. Within 2 seconds, the holdover LED lit.
>>> immediately turned it off and within a few more seconds, the
>>> oldover LED was back off. The GPS antenna is perhaps 35 feet away
>>> ith a cinder block wall, a brick wall, and a metal roof in between. I
>>> lso put a 15 Db attenuator between it and the antenna with almost the
>>> ame result. I am going to do more testing with it wired into the GPS
>>> ownfeed an an adjustable attenuator in line just to see how much
>>> ignal it takes. That way, there will be little danger of messing with
>>> nyone's reception. It is just a simple sweeper so it must do its job
>>> y brute force. I am amazed that it took so little to shut my Z3801
>>> own. Has anyone here had any actual experience testing GPS receivers
>>> or susceptibility?
>>> ___
>>> ime-nuts mailing list -- time-nuts@febo.com
>>> o unsubscribe, go to
>>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>>> nd follow the instructions there.
>>> 
>>> 
>>> ___
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>>> and follow the instructions there.
>> 
>> 
>> ___
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>> and follow the instructions there.
>> 
>> 
> 
> 
> 
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Re: [time-nuts] GPS simulator,

[J. Forster]

Agreed. The trick is to properly partition what is done in hardware ane
what is done in software. This could eliminate a lot of logic hardware.

Clearly, the RF stuff and modulator are hardware.
Ditto PR code generation.
Everything else in SW, I think.

FWIW,

-John

===


> Hi
>
> One bit serial at 16 MHz isn't all that fancy any more. Sounds like a
> shift register feeding a couple filters.
>
> The money must be in the receive side.
>
> Bob
>
> On Nov 24, 2010, at 5:14 PM, erniepe...@aol.com wrote:
>
>>
>>
>>
>> Hi,
>>
>>   found an interesting unit. I think it is not for the usual pocket
>> money for a time-nuts.
>>   have a look...
>>
>>   http://www.chronos.co.uk/pdfs/rac/labsat.pdf
>>
>> Rgds Ernie.
>>
>>
>>
>>
>>
>>
>>
>>
>>
>> -Original Message-
>> From: John Green 
>> To: time-nuts@febo.com
>> Sent: Mon, Nov 22, 2010 6:43 pm
>> Subject: [time-nuts] GPS jamming susceptibility
>>
>>
>> Given that this is an extremely sensitive topic and completely illegal
>> lso, let me just state at the outset that I have no interest in
>> amming anyone's GPS. A while back, I was looking at one of those
>> hinese discount electronics websites, I'm sure we all have, and
>> oticed a GPS jammer for sale. I had been wanting to do some jamming
>> usceptibility testing for quite some time but had never got around to
>> uilding a generator to test with. The thing was cheap so I ordered
>> t. After it arrived, I opened it up, first thing, to see how it was
>> ade. It has a dual 555 oscillator, a couple of analog switches, a 1.9
>> Hz VCO, a single amplifier. It doesn't look capable of putting out
>> ore than 50 milliwatts or so into a 2 inch antenna. I was somewhat
>> ubious that it would do anything, so I took it to the bench where the
>> 3801 lives and turned it on. Within 2 seconds, the holdover LED lit.
>> immediately turned it off and within a few more seconds, the
>> oldover LED was back off. The GPS antenna is perhaps 35 feet away
>> ith a cinder block wall, a brick wall, and a metal roof in between. I
>> lso put a 15 Db attenuator between it and the antenna with almost the
>> ame result. I am going to do more testing with it wired into the GPS
>> ownfeed an an adjustable attenuator in line just to see how much
>> ignal it takes. That way, there will be little danger of messing with
>> nyone's reception. It is just a simple sweeper so it must do its job
>> y brute force. I am amazed that it took so little to shut my Z3801
>> own. Has anyone here had any actual experience testing GPS receivers
>> or susceptibility?
>> ___
>> ime-nuts mailing list -- time-nuts@febo.com
>> o unsubscribe, go to
>> https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
>> nd 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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>
>



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Re: [time-nuts] GPS simulator,

[Bob Camp]

Hi

One bit serial at 16 MHz isn't all that fancy any more. Sounds like a shift 
register feeding a couple filters. 

The money must be in the receive side.

Bob

On Nov 24, 2010, at 5:14 PM, erniepe...@aol.com wrote:

> 
> 
> 
> Hi,
> 
>   found an interesting unit. I think it is not for the usual pocket money for 
> a time-nuts.
>   have a look... 
> 
>   http://www.chronos.co.uk/pdfs/rac/labsat.pdf
> 
> Rgds Ernie.
> 
> 
> 
> 
> 
> 
> 
> 
> 
> -Original Message-
> From: John Green 
> To: time-nuts@febo.com
> Sent: Mon, Nov 22, 2010 6:43 pm
> Subject: [time-nuts] GPS jamming susceptibility
> 
> 
> Given that this is an extremely sensitive topic and completely illegal
> lso, let me just state at the outset that I have no interest in
> amming anyone's GPS. A while back, I was looking at one of those
> hinese discount electronics websites, I'm sure we all have, and
> oticed a GPS jammer for sale. I had been wanting to do some jamming
> usceptibility testing for quite some time but had never got around to
> uilding a generator to test with. The thing was cheap so I ordered
> t. After it arrived, I opened it up, first thing, to see how it was
> ade. It has a dual 555 oscillator, a couple of analog switches, a 1.9
> Hz VCO, a single amplifier. It doesn't look capable of putting out
> ore than 50 milliwatts or so into a 2 inch antenna. I was somewhat
> ubious that it would do anything, so I took it to the bench where the
> 3801 lives and turned it on. Within 2 seconds, the holdover LED lit.
> immediately turned it off and within a few more seconds, the
> oldover LED was back off. The GPS antenna is perhaps 35 feet away
> ith a cinder block wall, a brick wall, and a metal roof in between. I
> lso put a 15 Db attenuator between it and the antenna with almost the
> ame result. I am going to do more testing with it wired into the GPS
> ownfeed an an adjustable attenuator in line just to see how much
> ignal it takes. That way, there will be little danger of messing with
> nyone's reception. It is just a simple sweeper so it must do its job
> y brute force. I am amazed that it took so little to shut my Z3801
> own. Has anyone here had any actual experience testing GPS receivers
> or susceptibility?
> ___
> ime-nuts mailing list -- time-nuts@febo.com
> o unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
> nd follow the instructions there.
> 
> 
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