[time-nuts] GPS at 60,000 feet (Chris Albertson)
Joseph Gauthier
joseph.gauthier at student.unsw.edu.au
Fri Feb 1 03:20:13 UTC 2013
ITAR has their own restrictions for GPS receivers. See here: http://www.fas.org/spp/starwars/offdocs/itar/p121.htm
"(2) Designed for producing navigation results above 60,000 feet altitude and at 1,000 knots velocity or greater;"
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Today's Topics:
1. Re: GPS at 60,000 feet (Chris Albertson)
2. Re: Low noise power supplies? (Poul-Henning Kamp)
3. Loran again (Rich and Marcia Putz)
4. Re: Low noise power supplies? (Charles P. Steinmetz)
5. Re: Low noise power supplies? (Adrian)
6. Re: Low noise power supplies? (SAIDJACK at aol.com)
7. Re: Low noise power supplies? (Bob Camp)
----------------------------------------------------------------------
Message: 1
Date: Thu, 31 Jan 2013 13:09:27 -0800
From: Chris Albertson <albertson.chris at gmail.com>
To: Discussion of precise time and frequency measurement
<time-nuts at febo.com>
Subject: Re: [time-nuts] GPS at 60,000 feet
Message-ID:
<CABbxVHsHVQYKznEpkcDPNeXiKvaVr0syTUHRvdUDu10vMrdunQ at mail.gmail.com>
Content-Type: text/plain; charset=ISO-8859-1
> I know for sure my handheld Garmin works at 27000 feet, at
> 530mph... ...I was actually surprised it worked up there.
> It made me wonder what the actual limits are.
What are the limits of your hand held unit or what are the limits of
GPS in general. I think GPS works as long as you are under the orbit
of the satellites. The company I used to work for placed GPS on some
low orbit spacecraft, so say roughly 200 miles up and 18,000 mph but
I'd guess most hand held units would not work in those conditions
Chris Albertson
Redondo Beach, California
------------------------------
Message: 2
Date: Thu, 31 Jan 2013 22:03:29 +0000
From: "Poul-Henning Kamp" <phk at phk.freebsd.dk>
To: Tom Van Baak <tvb at leapsecond.com>, Discussion of precise time and
frequency measurement <time-nuts at febo.com>
Subject: Re: [time-nuts] Low noise power supplies?
Message-ID: <1781.1359669809 at critter.freebsd.dk>
Content-Type: text/plain; charset=ISO-8859-1
--------
In message <C7259FFFCD3E42C2815B939BA386A0A8 at pc52>, "Tom Van Baak" writes:
>We have rigorous ways to compare and report oscillator performance;
>both as numbers and as plots. Is there something equivalent for
>power supplies?
Phase Noise measured on a 0Hz carrier ?
If you want the dynamic behaviour, it gets much more tricky, because
then you have both the spectrum of the load-changes and the
supply-changes, resulting in a spectrum output from the PSU.
--
Poul-Henning Kamp | UNIX since Zilog Zeus 3.20
phk at 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.
------------------------------
Message: 3
Date: Thu, 31 Jan 2013 19:01:29 -0500
From: "Rich and Marcia Putz" <rputz at bnin.net>
To: <time-nuts at febo.com>
Subject: [time-nuts] Loran again
Message-ID: <F4410DBD97D74D7D98878858B47F5323 at MAINCOMPUTER>
Content-Type: text/plain; charset="iso-8859-1"
Hi all;
I'm hearing Loran C signals @ 7:00 pm EST hear northern Indiana this evening. Anyone else?
Rich
W9ENG
------------------------------
Message: 4
Date: Thu, 31 Jan 2013 19:20:16 -0500
From: "Charles P. Steinmetz" <charles_steinmetz at lavabit.com>
To: Discussion of precise time and frequency measurement
<time-nuts at febo.com>
Subject: Re: [time-nuts] Low noise power supplies?
Message-ID: <20130201002020.7476211B89D at karen.lavabit.com>
Content-Type: text/plain; charset="us-ascii"; format=flowed
tvb wrote:
>I'll answer the question with anther question -- how does one
>properly measure power supply noise? Does it boil down to a single
>number, a couple of key numbers, or is it a plot, or several plots?
There are a number of "standard" ways, some of which have been
mentioned by others, none of which is all that helpful IMO.
What I find most useful is a plot of noise density vs. frequency
from, say, 0.1 Hz to as high as you require. The data should be
taken and processed with sufficient frequency resolution to show any
spurs in the band of interest. It is often helpful to have several
plots, each covering part of the band of interest, to improve the
displayed resolution of spurs.
NOTE: Designing a preamp for collecting the data is far from
trivial. Articles have been written about it (see, for example,
Linear Technology Application Note 124 by Jim Williams
<www.linear.com/docs/28585>).
Best regards,
Charles
------------------------------
Message: 5
Date: Fri, 01 Feb 2013 01:51:33 +0100
From: Adrian <rfnuts at arcor.de>
To: Discussion of precise time and frequency measurement
<time-nuts at febo.com>
Subject: Re: [time-nuts] Low noise power supplies?
Message-ID: <510B1195.9020801 at arcor.de>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Charles,
thanks for posting. That is the LTC application note I had in mind.
And here is Bruce's contribution to low noise PS design and measurement:
http://www.ko4bb.com/~bruce/LowNoisePowerSupplies.html
Don't miss to scroll fully down. There is a link to an IEEE paper
discussing chemical battery noise measurement.
Adrian
Charles P. Steinmetz schrieb:
> tvb wrote:
>
>> I'll answer the question with anther question -- how does one
>> properly measure power supply noise? Does it boil down to a single
>> number, a couple of key numbers, or is it a plot, or several plots?
>
> There are a number of "standard" ways, some of which have been
> mentioned by others, none of which is all that helpful IMO.
>
> What I find most useful is a plot of noise density vs. frequency from,
> say, 0.1 Hz to as high as you require. The data should be taken and
> processed with sufficient frequency resolution to show any spurs in
> the band of interest. It is often helpful to have several plots, each
> covering part of the band of interest, to improve the displayed
> resolution of spurs.
>
> NOTE: Designing a preamp for collecting the data is far from
> trivial. Articles have been written about it (see, for example,
> Linear Technology Application Note 124 by Jim Williams
> <www.linear.com/docs/28585>).
>
> Best regards,
>
> Charles
>
>
>
>
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> To unsubscribe, go to
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------------------------------
Message: 6
Date: Thu, 31 Jan 2013 20:13:40 -0500 (EST)
From: SAIDJACK at aol.com
To: time-nuts at febo.com
Subject: Re: [time-nuts] Low noise power supplies?
Message-ID: <1fb74.59aa1abe.3e3c70c4 at aol.com>
Content-Type: text/plain; charset="ISO-8859-1"
Or a good battery as a source for the regulators as discussed in this
thread already.
It's quite nice to have all the different Voltages available at the same
time, with up to 200mA.
bye,
Said
In a message dated 1/31/2013 13:12:33 Pacific Standard Time, lists at rtty.us
writes:
Hi
For $393.75 does it come with a wall wart?
If not I would definitely go for a "medical" ground isolated / low leakage
version to power the beast. The added cost over a plain jane wall wart
won't
add much to the purchase price percentage wise.
Bob
-----Original Message-----
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
Behalf Of SAIDJACK at aol.com
Sent: Thursday, January 31, 2013 3:58 PM
To: time-nuts at febo.com; lester at veenstras.com
Subject: Re: [time-nuts] Low noise power supplies?
Not sure if anyone posted this here yet, but Abracom has a very low noise
(7nV/RtHz at 1KHz) power source for VCO's etc, with various outputs. It's
sold on DIgikey or Mouser I think.
Here is a review of that unit:
_http://jaunty-electronics.com/blog/category/reviews/_
(http://jaunty-electronics.com/blog/category/reviews/)
Co-incidentally he also has a review of one of our units on the same page.
This is a very handy and reasonably priced power supply for many
low-noise
type of experiments.
bye,
Said
In a message dated 1/30/2013 21:36:50 Pacific Standard Time,
bruce.griffiths at xtra.co.nz writes:
Lester Veenstra wrote:
> The typical test supply on a bench for clean VCO testing is a small gel
cell
> battery. For a regulated power supply, make one using a 723. The 723
has
> far lower noise out than the monolithic regulators.
>
>
Depends on the variety of 723 some are noisier than others.
Some use an internal zener reference, some use a bandgap reference.
The original used a zener reference.
Bruce
> Lester B Veenstra M?YCM K1YCM W8YCM
> lester at veenstras.com
>
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> -----Original Message-----
> From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
> Behalf Of Richard (Rick) Karlquist
> Sent: Wednesday, January 30, 2013 9:17 PM
> To: Discussion of precise time and frequency measurement
> Subject: [time-nuts] Low noise power supplies?
>
>
> I know this topic has been discussed in the past on the list, but a
> colleague is asking if there are any off the shelf low noise power
supplies
> for testing oscillators. Something a cut above an HP "brick" lab power
> supply etc. They are hoping to avoid having to homebrew a power
> conditioning circuit.
> Did we ever arrive at a concensus as to the state of the art in homebrew
> power conditioning circuits?
>
> Any help would be appreciated.
>
> Rick Karlquist N6RK
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Message: 7
Date: Thu, 31 Jan 2013 21:02:32 -0500
From: Bob Camp <lists at rtty.us>
To: Discussion of precise time and frequency measurement
<time-nuts at febo.com>
Subject: Re: [time-nuts] Low noise power supplies?
Message-ID: <39C27A0C-3F9E-4F07-ABDC-27D26DE01848 at rtty.us>
Content-Type: text/plain; charset=us-ascii
Hi
If you are driving a spectrum analyzer, the 10,000X mentioned in the app note simply is not needed. A gain of 10X or less will get you to below 2 nv / sqrt(Hz) at 100 Hz and beyond. A 10 Hz blocking cap does not need to be a "24 hours to stabilize" device. An AD 797, a couple of metal film resistors, and a fairly large (say 47 uf) plastic cap work pretty well.
Bob
On Jan 31, 2013, at 7:20 PM, Charles P. Steinmetz <charles_steinmetz at lavabit.com> wrote:
> tvb wrote:
>
>> I'll answer the question with anther question -- how does one properly measure power supply noise? Does it boil down to a single number, a couple of key numbers, or is it a plot, or several plots?
>
> There are a number of "standard" ways, some of which have been mentioned by others, none of which is all that helpful IMO.
>
> What I find most useful is a plot of noise density vs. frequency from, say, 0.1 Hz to as high as you require. The data should be taken and processed with sufficient frequency resolution to show any spurs in the band of interest. It is often helpful to have several plots, each covering part of the band of interest, to improve the displayed resolution of spurs.
>
> NOTE: Designing a preamp for collecting the data is far from trivial. Articles have been written about it (see, for example, Linear Technology Application Note 124 by Jim Williams <www.linear.com/docs/28585>).
>
> Best regards,
>
> Charles
>
>
>
>
> _______________________________________________
> time-nuts mailing list -- time-nuts at 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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