[time-nuts] indoor GPS test. (KC8YEY)
Skelly, Francis J. Jr.
skellyfj at muohio.edu
Fri Jan 25 16:35:36 UTC 2008
I have had good success with the Garmin 15H indoors achieving DGPS / WAAS positioning accuracy.
Frank - KC8YEY
-----Original Message-----
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On Behalf Of time-nuts-request at febo.com
Sent: Friday, January 25, 2008 8:48 AM
To: time-nuts at febo.com
Subject: time-nuts Digest, Vol 42, Issue 62
Send time-nuts mailing list submissions to
time-nuts at febo.com
To subscribe or unsubscribe via the World Wide Web, visit
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
or, via email, send a message with subject or body 'help' to
time-nuts-request at febo.com
You can reach the person managing the list at
time-nuts-owner at febo.com
When replying, please edit your Subject line so it is more specific
than "Re: Contents of time-nuts digest..."
Today's Topics:
1. Re: indoor GPS test. (WB6BNQ)
2. Generation of very stable 10.001MHz for heterodyne freq
measurement (Anders Time)
3. Re: Generation of very stable 10.001MHz for heterodyne freq
measurement (John Ackermann N8UR)
4. Low phase noise digital divider (in 600MHz to10MHz area)
(Anders Time)
5. Re: Low phase noise digital divider (in 600MHz to10MHz area)
(Didier Juges)
6. Z3801A performance plots (John Ackermann N8UR)
7. Re: Generation of very stable 10.001MHz for heterodyne freq
measurement (Bruce Griffiths)
8. Re: Z3801A performance plots (Mike Feher)
9. Re: Z3801A performance plots (Magne M?hre)
10. Re: Low phase noise digital divider (in 600MHz to10MHz area)
(Bruce Griffiths)
----------------------------------------------------------------------
Message: 1
Date: Fri, 25 Jan 2008 02:43:04 -0800
From: WB6BNQ <wb6bnq at cox.net>
Subject: Re: [time-nuts] indoor GPS test.
To: Discussion of precise time and frequency measurement
<time-nuts at febo.com>
Message-ID: <4799BD38.DDAD97D0 at cox.net>
Content-Type: text/plain; charset=us-ascii
By the way,
If you do get a Garmin 15, make sure it is the "H" or "L" model which has WAAS. The
regular model "15," which is cheaper, does not have WAAS.
Bill....WB6BNQ
WB6BNQ wrote:
> If you go to the Garmin web site and look at their OEM page, you can order the
> OEM versions for around $55 from Garmin directly. I have one of their models, a
> 15xx OEM module (including the pigtail cable). It has PPS stated as good to 1us
> but I was told it was actually good to 100ns with SA turned off. It is not
> designed to be a "timing" receiver, but will get you in the ball park for a cheap
> price. You will still need to get an antenna of some sort, supply power and use
> software in a PC to setup and control the unit.
>
> I purchased the Garmin 15 to use in my car, as my main GPS unit developed a
> failure. I was using my main unit to drive my laptop software for mapping
> purposes. The Garmin 15 will replace it.
>
> Bill....WB6BNQ
>
> Hal Murray wrote:
>
> > > The GPS 18 from Garmin is ~130 list, since ti comes with some software
> > > for a laptop.
> >
> > You want the GPC 18 LVC rather than any of the other versions. (It's the
> > only one with PPS.)
> >
> > You can get it for well under $100. Look for the OEM version. (aka no
> > software)
> >
> > I got mine from Provantage.
> > http://www.provantage.com/garmin-010-00321-56~7GRMN039.htm
> >
> > --
> > These are my opinions, not necessarily my employer's. I hate spam.
> >
> > _______________________________________________
> > 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.
>
> _______________________________________________
> 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.
------------------------------
Message: 2
Date: Fri, 25 Jan 2008 13:23:56 +0100
From: "Anders Time" <anderstime at gmail.com>
Subject: [time-nuts] Generation of very stable 10.001MHz for
heterodyne freq measurement
To: time-nuts at febo.com
Message-ID:
<7a60526d0801250423i4240694egef892cd1a714925c at mail.gmail.com>
Content-Type: text/plain; charset=ISO-8859-1
What is the best way to generate a very stable 10.001MHz(low E-13 or
-110dBc/1Hz) to be to do high resolution heterodyne(Allan deviation)
measurements?
Using DDS?
Using PTS 500 or 250 synth and divide? Using HP 8662A and divide?
Some smart pll circuit by locking the 1000Hz to the reference in some way?
Thanks
Anders
------------------------------
Message: 3
Date: Fri, 25 Jan 2008 07:56:53 -0500
From: John Ackermann N8UR <jra at febo.com>
Subject: Re: [time-nuts] Generation of very stable 10.001MHz for
heterodyne freq measurement
To: Discussion of precise time and frequency measurement
<time-nuts at febo.com>
Message-ID: <4799DC95.1040201 at febo.com>
Content-Type: text/plain; charset=us-ascii
Anders Time said the following on 01/25/2008 07:23 AM:
> What is the best way to generate a very stable 10.001MHz(low E-13 or
> -110dBc/1Hz) to be to do high resolution heterodyne(Allan deviation)
> measurements?
> Using DDS?
> Using PTS 500 or 250 synth and divide? Using HP 8662A and divide?
> Some smart pll circuit by locking the 1000Hz to the reference in some way?
> Thanks
> Anders
Rick Karlquist has published a design for a very low noise synthesizer
designed for just this application. Unfortunately, I don't have a link
to that handy, but it's on his website.
I just took a look at some measurements I did on a PTS-250-SX51 (special
version with low noise output to 25 MHz via an internal divider) and it
looks like it would barely meet your requirements -- around 2x10e-13 at
1 second, and about -115 dBc/Hz at 1 Hz offset:
http://www.febo.com/pages/pts_synth/images/pts-250-sx51-adev.png
http://www.febo.com/pages/pts_synth/images/pts-250-sx51-spectrum.png
However, that was at 10.000... MHz; the performance, particularly with
respect to spurs, changes as the decimal dividers kick in for more
complex frequencies.
John
------------------------------
Message: 4
Date: Fri, 25 Jan 2008 14:01:56 +0100
From: "Anders Time" <anderstime at gmail.com>
Subject: [time-nuts] Low phase noise digital divider (in 600MHz
to10MHz area)
To: time-nuts at febo.com
Message-ID:
<7a60526d0801250501u78df61bbm419520baec84762 at mail.gmail.com>
Content-Type: text/plain; charset=ISO-8859-1
Have been locking around for a good article on how to design a good Low
phase noise digital divider(in 600MHz to 10MHz area), but the have not found
any good literature. Today most people talk about regenerative dividers, but
are a rather complex subject.
Does anyone have experience in what logic family that have the lowest noise
TTL, AC, HC, F etc?
What is the upper limit for ECL diviers? My first idea was to use ECL to
divide down to 100MHz area and then to use lower noise TTL to go down to
10MHz.
What about edge-conditioning circuit at divider input? Have seen people talk
about it, but no info what it does?
Thanks
Anders
------------------------------
Message: 5
Date: Fri, 25 Jan 2008 07:14:33 -0600
From: "Didier Juges" <didier at cox.net>
Subject: Re: [time-nuts] Low phase noise digital divider (in 600MHz
to10MHz area)
To: "'Discussion of precise time and frequency measurement'"
<time-nuts at febo.com>
Message-ID: <001801c85f54$3abbd8e0$0a01a8c0 at didierhp>
Content-Type: text/plain; charset="windows-1250"
There was a thread some time ago just about that. It was probably 2007, so
if you look in the archives, you should find it.
I will look for it too, as I want to index it for future reference, and if I
find it first, I'll post it again.
Didier
> -----Original Message-----
> From: time-nuts-bounces at febo.com
> [mailto:time-nuts-bounces at febo.com] On Behalf Of Anders Time
> Sent: Friday, January 25, 2008 7:02 AM
> To: time-nuts at febo.com
> Subject: [time-nuts] Low phase noise digital divider (in
> 600MHz to10MHz area)
>
> Have been locking around for a good article on how to design
> a good Low phase noise digital divider(in 600MHz to 10MHz
> area), but the have not found any good literature. Today most
> people talk about regenerative dividers, but are a rather
> complex subject.
> Does anyone have experience in what logic family that have
> the lowest noise TTL, AC, HC, F etc?
> What is the upper limit for ECL diviers? My first idea was to
> use ECL to divide down to 100MHz area and then to use lower
> noise TTL to go down to 10MHz.
> What about edge-conditioning circuit at divider input? Have
> seen people talk about it, but no info what it does?
> Thanks
> Anders
No virus found in this outgoing message.
Checked by AVG Free Edition.
Version: 7.5.516 / Virus Database: 269.19.11/1242 - Release Date: 1/24/2008
8:32 PM
------------------------------
Message: 6
Date: Fri, 25 Jan 2008 08:33:59 -0500
From: John Ackermann N8UR <jra at febo.com>
Subject: [time-nuts] Z3801A performance plots
To: Discussion of precise time and frequency measurement
<time-nuts at febo.com>
Message-ID: <4799E547.8000209 at febo.com>
Content-Type: text/plain; charset=ISO-8859-1
I realized that there hasn't been data posted about how the Z3801A
performs when operating normally in GPS lock mode -- TVB's excellent
page focuses on the oscillators when they are free running.
So, I just did an experiment measuring two well aged Z3801As in GPS lock
against one another. No huge enlightenment resulted, but the plot shows
very clearly what happens when the GPS steering kicks in.
http://www.febo.com/pages/oscillators/z3801A/index.html
John
------------------------------
Message: 7
Date: Sat, 26 Jan 2008 02:39:11 +1300
From: Bruce Griffiths <bruce.griffiths at xtra.co.nz>
Subject: Re: [time-nuts] Generation of very stable 10.001MHz for
heterodyne freq measurement
To: Discussion of precise time and frequency measurement
<time-nuts at febo.com>
Message-ID: <4799E67F.2060404 at xtra.co.nz>
Content-Type: text/plain; charset=ISO-8859-1
Anders Time wrote:
> What is the best way to generate a very stable 10.001MHz(low E-13 or
> -110dBc/1Hz) to be to do high resolution heterodyne(Allan deviation)
> measurements?
> Using DDS?
> Using PTS 500 or 250 synth and divide? Using HP 8662A and divide?
> Some smart pll circuit by locking the 1000Hz to the reference in some way?
> Thanks
> Anders
> _______________________________________________
> 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.
>
>
Anders
Its far easier to produce 9.999MHz cleanly than 10.001MHz
The simplest and quietest way is to use a pair of cascaded SSB mixers:
The first SSB mixer is an LSB mixer that subtracts (10MHz / 100) from
10MHz to produce 9.9MHz.
The second SSB mixer is a USB mixer that adds (9.9MHz/100) to 9.9MHz to
produce 9.999MHz.
i.e. 10MHz*(1 + 1/100)*(1-1/100) = 9.999MHz
Follow the USB mixer with a cleanup PLL using a low noise OCXO, however
you will need a custom crystal.
This is why NIST used a 10Hz offset with a 10MHz input and NIST + JPL
use a 100Hz offset with a 100MHz input no custom crystal is required its
easy enough to offset a standard 10MHz OCXO by 1ppm.
Process is similar:
9.99999MHz = 10.00MHz (1-1/1000)*(1+1/1000)
One could also use a USB mixer
10.001MHz = 10MHz*(1+1/10,000) but it may be more difficult to filter
out the residual 9.999MHz component in the USB output.
Synthesizers seem attractive, but in practice they have lots of spurs
that can interfere unless you choose a suitable offset like 123 Hz as
adopted by JPL to minimise synthesizers spurs when using a commercial
synthesizer.
Bruce
------------------------------
Message: 8
Date: Fri, 25 Jan 2008 08:41:09 -0500
From: "Mike Feher" <mfeher at eozinc.com>
Subject: Re: [time-nuts] Z3801A performance plots
To: "'Discussion of precise time and frequency measurement'"
<time-nuts at febo.com>
Message-ID: <005201c85f57$f3cfe260$0201a8c0 at gsmacdq14es>
Content-Type: text/plain; charset="us-ascii"
John -
Your link did not work for me. Thanks - Mike
Mike B. Feher, N4FS
89 Arnold Blvd.
Howell, NJ, 07731
732-886-5960
-----Original Message-----
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
Behalf Of John Ackermann N8UR
Sent: Friday, January 25, 2008 8:34 AM
To: Discussion of precise time and frequency measurement
Subject: [time-nuts] Z3801A performance plots
I realized that there hasn't been data posted about how the Z3801A
performs when operating normally in GPS lock mode -- TVB's excellent
page focuses on the oscillators when they are free running.
So, I just did an experiment measuring two well aged Z3801As in GPS lock
against one another. No huge enlightenment resulted, but the plot shows
very clearly what happens when the GPS steering kicks in.
http://www.febo.com/pages/oscillators/z3801A/index.html
John
_______________________________________________
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.
------------------------------
Message: 9
Date: Fri, 25 Jan 2008 14:41:00 +0100
From: Magne M?hre <magne at samfundet.no>
Subject: Re: [time-nuts] Z3801A performance plots
To: Discussion of precise time and frequency measurement
<time-nuts at febo.com>
Message-ID: <4799E6EC.1010202 at samfundet.no>
Content-Type: text/plain; format=flowed; charset=UTF-8
John Ackermann N8UR wrote:
> I realized that there hasn't been data posted about how the Z3801A
> performs when operating normally in GPS lock mode -- TVB's excellent
> page focuses on the oscillators when they are free running.
>
> So, I just did an experiment measuring two well aged Z3801As in GPS lock
> against one another. No huge enlightenment resulted, but the plot shows
> very clearly what happens when the GPS steering kicks in.
>
> http://www.febo.com/pages/oscillators/z3801A/index.html
http://www.febo.com/pages/oscillators/z3801a/index.html
seems to be the correct URL :)
--Magne
------------------------------
Message: 10
Date: Sat, 26 Jan 2008 02:47:38 +1300
From: Bruce Griffiths <bruce.griffiths at xtra.co.nz>
Subject: Re: [time-nuts] Low phase noise digital divider (in 600MHz
to10MHz area)
To: Discussion of precise time and frequency measurement
<time-nuts at febo.com>
Message-ID: <4799E87A.30704 at xtra.co.nz>
Content-Type: text/plain; charset=ISO-8859-1
Anders Time wrote:
> Have been locking around for a good article on how to design a good Low
> phase noise digital divider(in 600MHz to 10MHz area), but the have not found
> any good literature. Today most people talk about regenerative dividers, but
> are a rather complex subject.
> Does anyone have experience in what logic family that have the lowest noise
> TTL, AC, HC, F etc?
> What is the upper limit for ECL diviers? My first idea was to use ECL to
> divide down to 100MHz area and then to use lower noise TTL to go down to
> 10MHz.
> What about edge-conditioning circuit at divider input? Have seen people talk
> about it, but no info what it does?
> Thanks
> Anders
>
Anders
The upper limit for current ECL dividers is well over 1 GHz.
Theres nothing terribly fancy about the edge conditioning circuit at a
divider input, its just a limiting amplifier or comparator used to
amplify the input signal and reduce the input transition times seen by
the divider.
If you are serious about low noise division dont forget to bandpass
filter the input to the divider and bandpass filter the output of each
divide by 16 followed by another clock shaper.
This process minimises the aliased noise at the divider output.
If you want to use a programmable divider this cascaded divide and
filter technique can become somewhat unwieldy.
F dividers are supposed to be quieter but I havent seen any definitive
measurements comparing like with like.
Bruce
------------------------------
_______________________________________________
time-nuts mailing list
time-nuts at febo.com
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
End of time-nuts Digest, Vol 42, Issue 62
*****************************************
More information about the Time-nuts_lists.febo.com
mailing list