Re: [time-nuts] temperature stability basics

In message <013e01cb8dc6$41b038a0$4001a...@lark>, "Alan Melia" writes: >I believe there is a reflective/foam insulator that is sold for setting >behind (what we in UK call ) CH radiators when the are mounted on outer >walls. That would meed Poul-Henning's temperature difference criteria, I >think.

Re: [time-nuts] ok, newbie questions

Those switch mode regulator modules under the finned heatsinks in the Z3815A are likely responsible for most of the spurs. The ECL/CML logic dividers and the various ouputs like 19.6608MHz also contribute. Since the E1938A output is only +4dBm, its very easy to degrade the phase noise in the b

Re: [time-nuts] temperature stability basics

Hi It's a fused fiber material, more like the stuff they make overnight shipping envelopes out of than a normal paper. It looks and feels more like tissue paper than anything else though. The same outgassing and particles floating around issues mess up the gaps in the sandwich. There are indeed

Re: [time-nuts] temperature stability basics

I'm virtually certain by 1968 they were using some plastic film. Maybe Mylar, maybe Kapton, but metalized plastic. I was doing optics and telemetry so was not really involved in other areas, but I babysat our payload on that bird first bird for 5 months -John > Bob Camp wrote: >> H

Re: [time-nuts] temperature stability basics

Bob Camp wrote: Hi The ones I'm talking about aren't used anywhere there's air to create any wind Bob yeah, but there's plenty of handling and air currents before it gets launched... These days, I'd vote for evaporated metal on some substrate.

Re: [time-nuts] temperature stability basics

Bob Camp wrote: Hi The gold color in a space thermal blanket is from - gold. The normal formula is to use gold leaf and tissue paper (not quite the Kleenex variety, but similar) in layers. The gold leaf is *very* good for IR reflection. The tissue paper is porous enough that there's very little

Re: [time-nuts] USB Low Cost GPS Timing Receiver

Hi Put another way: If you set up / sync up a time source based on a cheap 1 ppm TCXO, you are good for more than 10,000 seconds after the sync. If your viewing period is in the 2 to 4 hour range, it should work out pretty well. Bob On Nov 26, 2010, at 7:58 PM, Brooke Clarke wrote: > Hi B

Re: [time-nuts] ok, newbie questions

Not necessarily so.. My HP Z3815A here (desktop unit) has horrible phase noise and massive spurs. Really to cry over since I know what the internal OCXO (1938A type) is capable of generating. See the attached plot. bye, Said In a message dated 11/26/2010 16:37:26 Pacific Standard Time

Re: [time-nuts] USB Low Cost GPS Timing Receiver

Some of the older GPSs had the 9 pin COM port connectors to interface with the mapping SW running on a PC laptop (Magellen or Garmin ?). Might that data stream contain good enough timing info? I don't knoe what protrocol they used. -John === > Hi Bill: > > The telescope has around a

Re: [time-nuts] ok, newbie questions

Hi A stand alone OCXO is good for telling you that where you are today is close to where you were yesterday. It's pretty much useless for telling you weather either of those places are the correct place to be. The GPS gizmo will do a pretty good job of telling you that where you are is indeed

Re: [time-nuts] USB Low Cost GPS Timing Receiver

Hi Bill: The telescope has around arc second pointing capability so I think he needs a hundredth of a second or slightly better. What's now done is to manually bring the scope onto a half dozen known stars (called a short run) which sets time in the tracking software. But if the tracking co

Re: [time-nuts] ok, newbie questions

In a message dated 26/11/2010 23:31:32 GMT Standard Time, w...@w2hx.com writes: Ahh. Very interesting explanation. So is it somewhat correct to assume (yes, I know) that for a stationary (non-mobile) environment, these extra sats don’t make much difference? This seems to be what the explan

Re: [time-nuts] temperature stability basics

> Dont get the idea that radiation is only significant for large > temperature differences. > For two parallel surfaces at any distance apart the black body > radiation between them (around room temperature 300K) is near to 6 > watts per square metre per degree (C*) of temperature difference. Only

Re: [time-nuts] temperature stability basics

Dont get the idea that radiation is only significant for large temperature differences. For two parallel surfaces at any distance apart the black body radiation between them (around room temperature 300K) is near to 6 watts per square metre per degree (C*) of temperature difference. That is

Re: [time-nuts] USB Low Cost GPS Timing Receiver

bro...@pacific.net said: > A friend is looking for a low cost GPS receiver to set the clock in the > computer that controls his telescope mount. USB would be nice but is not a > requirement. What sort of accuracy does your friend need? > For example does eBay item 130456356506 set the computer

Re: [time-nuts] temperature stability basics

Hi The ones I'm talking about aren't used anywhere there's air to create any wind Bob On Nov 26, 2010, at 6:52 PM, J. Forster wrote: > Not leaf in the ones I've seen. It's very clearly a metalized plastic > film. Gold leaf has virtually no structural strength. A breeze will tear > it. I a

Re: [time-nuts] ok, newbie questions

Hi In a decent location, with a good antenna, you can do just fine with an eight channel receiver. In a poor enough location, a million correlators might indeed improve things over a hundred thousand correlators. Are you mounting your antenna outdoors? Does it have a clear view of the sky? Do

Re: [time-nuts] temperature stability basics

I believe there is a reflective/foam insulator that is sold for setting behind (what we in UK call ) CH radiators when the are mounted on outer walls. That would meed Poul-Henning's temperature difference criteria, I think. Interesting topic may me revise some 50 year old very rusty physics :-)) A

Re: [time-nuts] temperature stability basics

Not leaf in the ones I've seen. It's very clearly a metalized plastic film. Gold leaf has virtually no structural strength. A breeze will tear it. I also doubt any tissue paper usage. Best, -John = > Hi > > The gold color in a space thermal blanket is from - gold. The normal >

Re: [time-nuts] temperature stability basics

Aren't the "space blankets" use in survival packs pretty much the same stuff? The mylar-air space-mylar construction seems pretty rational, and they are windproof. -John === > Hal Murray wrote: >> namic...@gmail.com said: >>> Find some closed cell polyethylene that is quite thin and

Re: [time-nuts] ok, newbie questions

W2HX wrote: Ahh. Very interesting explanation. So is it somewhat correct to assume (yes, I know) that for a stationary (non-mobile) environment, these extra sats don’t make much difference? This seems to be what the explanation is saying. Depends on your antenna location and type. The extra sa

Re: [time-nuts] temperature stability basics

Hi The gold color in a space thermal blanket is from - gold. The normal formula is to use gold leaf and tissue paper (not quite the Kleenex variety, but similar) in layers. The gold leaf is *very* good for IR reflection. The tissue paper is porous enough that there's very little air trapped in

Re: [time-nuts] temperature stability basics

J. Forster wrote: That's what those golden thermal blankets are on spacecraft and in cryostats. I'm not quite sure whether the golden color comes from a deposited film of Au, or whether it's color comes from the Mylar. It's more likely the former. I've seen the stuff up close, but have not worked

Re: [time-nuts] ok, newbie questions

> Ahh. Very interesting explanation. So is it somewhat correct to assume > (yes, > I know) that for a stationary (non-mobile) environment, these extra sats > don’t make much difference? This seems to be what the explanation is > saying. Pretty much, although if your view of the satellites is obscu

Re: [time-nuts] temperature stability basics

Hal Murray wrote: namic...@gmail.com said: Find some closed cell polyethylene that is quite thin and some very light aluminium foil and you could make many layers. How about aluminized Mylar? If the many-reflective-layers idea really works, I'd expect somebody to sell foam built that way. W

Re: [time-nuts] temperature stability basics

In message <20101126223543.71514800...@ip-64-139-1-69.sjc.megapath.net>, Hal Mu rray writes: >How about aluminized Mylar? Reflective insulation only works if you have significantly different temperatures. Look up Stefan-Bolzmanns law, and notice the T^4 term, but pay attention to T being absolut

Re: [time-nuts] ok, newbie questions

Ahh. Very interesting explanation. So is it somewhat correct to assume (yes, I know) that for a stationary (non-mobile) environment, these extra sats don’t make much difference? This seems to be what the explanation is saying. Ok. So let me see. For a frequency standard for use in lab equipment, i

Re: [time-nuts] What's the latest correct PICTIC II Mouser project?

Anyone have a different/later PICTIC II parts list (or from an alternate supplier)? Thanks, Dave On Fri, Aug 6, 2010 at 1:02 PM, Bob Camp wrote: > Hi > > I believe the project at: > > http://www.mouser.com/ProjectManager/ProjectDetail.aspx?AccessID=8736DCEE10 > > is up to date in (no un-order

Re: [time-nuts] temperature stability basics

That's what those golden thermal blankets are on spacecraft and in cryostats. I'm not quite sure whether the golden color comes from a deposited film of Au, or whether it's color comes from the Mylar. It's more likely the former. I've seen the stuff up close, but have not worked wit it personally.

Re: [time-nuts] temperature stability basics

namic...@gmail.com said: > Find some closed cell polyethylene that is quite thin and some very light > aluminium foil and you could make many layers. How about aluminized Mylar? If the many-reflective-layers idea really works, I'd expect somebody to sell foam built that way. Why don't they? -

Re: [time-nuts] USB Low Cost GPS Timing Receiver

Brooke, Google says the SD-200 speaks 4800 baud NMEA at 1 second intervals. It is not clear whether the message is fixed of if it will reply to queries. Your question only concerned cost. Is one second accuracy adequate? Bill Hawkins -Original Message- From: bro...@pacific.net Sent:

Re: [time-nuts] USB Low Cost GPS Timing Receiver

-Ursprüngliche Nachricht- Von: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] Im Auftrag von bro...@pacific.net Gesendet: Freitag, 26. November 2010 22:43 An: time-nuts@febo.com Betreff: [time-nuts] USB Low Cost GPS Timing Receiver Hi: A friend is looking for a low cost

Re: [time-nuts] ok, newbie questions

> Yes I agree a newer thunderbolt would surely suffice for me and probably > also the ocxo in my 8662A synth > > But I am still academically curious about the impact of more channels of > satellites? What is the value of these extra sats? > Thanks! In a mobile scenario, you need measurements to fo

[time-nuts] USB Low Cost GPS Timing Receiver

Hi: A friend is looking for a low cost GPS receiver to set the clock in the computer that controls his telescope mount. USB would be nice but is not a requirement. For example does eBay item 130456356506 set the computer clock? This GPS receiver for the Nikon has a mini-USB connector, but when

Re: [time-nuts] ok, newbie questions

Hi Eugene, the extra channels usually come on more modern GPS receivers that also give you sometimes much higher sensitivity, much faster lock time, less 1PPS jitter, sometimes WAAS/SBAS capability, and last but not least more redundancy and better performance in environments with multipath

Re: [time-nuts] Thunderbolt & Lady Heather 48 hour precision survey

I'm running another test now and it's significantly improved after the 48 hour survey. Before I'd see several degree swings over the course of an hour, now it's more like 1.1 degrees in the last 8 hours. The problem here is I didn't do anything to the styrofoam box, but the idea was to keep tempe

Re: [time-nuts] temperature stability basics

On 11/26/2010 07:17 PM, Mark Sims wrote: One thing to be aware of with the LM35 type of sensors in the TO92 package is that virtually all of the temperature input to the chip is via the leads (fine print in the data sheet). I have seen several places with the device package epoxied to some s

Re: [time-nuts] ok, newbie questions

Yes I agree a newer thunderbolt would surely suffice for me and probably also the ocxo in my 8662A synth But I am still academically curious about the impact of more channels of satellites? What is the value of these extra sats? Thanks! On Fri, 26 Nov 2010 13:01:12 -0500, wrote: > Hi > > Fir

Re: [time-nuts] Thunderbolt & Lady Heather 48 hour precision survey

On Fri, Nov 26, 2010 at 6:41 AM, Robert Darlington wrote: > I keep it in a styrofoam beer cooler surrounded with bottled water in a > draft free area and it's been all over the map. Robert- Are you doing this for temperature stability? How stable is it? Dave _

[time-nuts] temperature stability basics

One thing to be aware of with the LM35 type of sensors in the TO92 package is that virtually all of the temperature input to the chip is via the leads (fine print in the data sheet).  I have seen several places with the device package epoxied to some surface or embedded in some insulation with

Re: [time-nuts] ok, newbie questions

Hi First option would be to dig into what you already have. There may be a pretty good OCXO in something on your bench. Any TBolt with a date code past 2001 should have a good OCXO in it. It's plenty good enough for what you are trying to do. Bob Sent from my iPhone On Nov 25, 2010, at 11:48

Re: [time-nuts] temperature stability basics

Hi The other answer is to let the temperature control electronics take care of the problem. If you are doing something inside that uses energy (like an oscillator) it have generate a heat rise through the insulation. Bob Sent from my iPhone On Nov 26, 2010, at 2:24 AM, "beale" wrote: > In a

Re: [time-nuts] GPS simulator,

Hi My guess is the 1 bit DAC is nothing more than the FPGA output pin. About all you really need is enough of a buffer to stay ahead of the USB bus. That may not be much with a modern USB chip set and a hand made driver on the PC. Bob Sent from my iPhone On Nov 26, 2010, at 10:34 AM, jimlux

Re: [time-nuts] ok, newbie questions

Certainly in the 1 in 10E9 region a scope is fine. Set the scope to trigger on the 1 PPS and look at your local 10 MHz at 10 or 20 nS/div. A storage or DSO scope makes this pretty easy. You can tweek your local osc pretty quickly this way. At 10 nS/div a 1 in 10E9 walks 1 div in ten seconds. FWIW

Re: [time-nuts] ok, newbie questions

Well, my 8662A I believe has an 10811A in it. Hard for me to imagine that I would be able to see this drift on the scope? But I've never thought about it so maybe I need to think more! But I don't mind spending a bit of $ to avoid the periodic scope-based calibration process to adjust. Although gr

Re: [time-nuts] ok, newbie questions

Hi Eugene, >From your comments and equipment list I guess you are looking for low noise >and stability rather than absolute accuracy. In this case I'd go ro a 10811 >OCXO. Check to make sure none of you existing equipment doesn't have one >already They were commonly fitted as high stab options.

Re: [time-nuts] temperature stability basics

In message <4cefd115.5030...@earthlink.net>, jimlux writes: >beale wrote: >What is done in real instruments that need good thermal insulation? >I assume dewar flasks are limited to aerospace applications. One good allround foam material is "Armaflex" -- Poul-Henning Kamp | UNIX since Zilo

Re: [time-nuts] FS700 schematic

did you have any luck? On Tue, Nov 23, 2010 at 8:05 PM, paul swed wrote: > Not a problem on spelling especially if tired. > The problem you are running into is really curious indeed. > Since we have no LORAN C in N A anymore. I can only use the loran simulator > to drive the FS700 and that works

Re: [time-nuts] temperature stability basics

Worse. Those books will start you thinking about home brew H MASERS. T^hey make UHV seem doable. -John === > John Strong's "Procedures in Experimental Physics" has a section on > thermal design (for furnaces and ovens), and is worth having a copy of.' > Moore, et.al., "building scie

Re: [time-nuts] [Bulk] ok, newbie questions

Joe, You are bust greasing an already slippery slope. :) -John == > Eugene, > > Welcome to the list and beware of how 'addicting' this can be. I started > out with your exact same purpose, minus all the equipment you have, and am > still a 'newbie'. > > First question is do y

Re: [time-nuts] temperature stability basics

Thermos flasks were pretty common on early crystal oscillatots, including GR, HP 107(?), and Sultzer at least. -John > 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,

Re: [time-nuts] GPS simulator,

> But they mention software to generate sequences. Hummm... right... so I think we need to look inside one to be sure what it is... lc ct1dmk. jimlux wrote: Luis Cupido wrote: Hi, The fact they refer that atmospheric s/n degradation and dropouts etc being replayed precisely lead me to thin

Re: [time-nuts] GPS simulator,

Luis Cupido wrote: Hi, The fact they refer that atmospheric s/n degradation and dropouts etc being replayed precisely lead me to think this is just a spectrum rec/play machine (no mod/demod of any kind) like the ham-oriented "time machine" but for GPS. http://www.expandedspectrumsystems.com/p

Re: [time-nuts] temperature stability basics

beale wrote: 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 do

Re: [time-nuts] [Bulk] ok, newbie questions - power supply

I'm using the TAPR HPSDR - LPU linear power supply to power a pair of Thunderbolts. It has switching for the -12VDC, but the +12 and +5 are linear. I didn't use the included ATX or PowerPole connectors, but wired direct. It runs fine from my 13.6 VDC house battery. Mike - AA8K On 11/26/201

Re: [time-nuts] GPS simulator,

Hi, The fact they refer that atmospheric s/n degradation and dropouts etc being replayed precisely lead me to think this is just a spectrum rec/play machine (no mod/demod of any kind) like the ham-oriented "time machine" but for GPS. http://www.expandedspectrumsystems.com/prod2.html Luis Cupi

Re: [time-nuts] Plastic covered OCXOs

Bruce wrote: http://www.rakon.com/Products/Public%20Documents/Specifications/RFPO40.pdf The following US patent application may or may not be instructive:

Re: [time-nuts] [Bulk] ok, newbie questions

Eugene, Welcome to the list and beware of how 'addicting' this can be. I started out with your exact same purpose, minus all the equipment you have, and am still a 'newbie'. First question is do you want a 'primary' standard (in essence, one that does not need to be calibrated) or a secondary st

Re: [time-nuts] temperature stability basics

Hi, I have been looking at a similar problem. What I have found is: many plastic foam materials have very low conduction but are transparent to long wavelength radiation, so thermal heating/cooling through them is mainly by thermal radiation. If you wrap an item in plastic foam, then a radiati

Re: [time-nuts] temperature stability basics

Hi Beale, From: "beale" I assume dewar flasks are limited to aerospace applications. :-) You keep your coffee hot in it! Bye, Jean-Louis Noel, OO1J ___ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-