David.vanhorn wrote:
> Measuring the speed of light (Fizeau or Michelson method? Other ways)
>
>
> I saw a great demo of this at the Exploratorium in SF. They had a long spool
> of fiber optic, a disc with holes, and a light source. When static, if the
> light shines through the hole in the di
Thank you bob and Gary for your investigations! I appreciate it! Here are a
couple more views:
https://imgur.com/a/auWdXvq
"This is the picture with sticker removed. The large IC at the back has its
label scratched off. ... that was intentional, but he has a note saying it is
a member of
On 5/11/18 7:07 AM, Philip Gladstone wrote:
On 11/05/2018 07:23, jimlux wrote:
On 5/10/18 9:55 PM, Hal Murray wrote:
A few months ago, I was a judge for the county level middle school
science
fair. (I'm not very good at what they wanted, but that's a different
problem.)
What sort of intere
What antenna are you using and where is it located? I have the
TruePosition with a Motorola PCTEL 8508851k66 antenna on a windowsill with
a ground plane under the antenna and it generally sees 4-7 sats. I have
seen some holdovers but it has been better after running for a while and
doing a survey.
It definitely works better on a windowsill than under the roof. It also did
not work at all with a patch antenna.
I can compare it to another GPSDO used as a reference and I see ADEV in the
range of 2.5E-10 for low Tau 10-1000s, heading down for larger Tau. I see
phase noise of -102 dBc/Hz at 10 H
Mark!
On Fri, 11 May 2018 21:02:59 +
Mark Sims wrote:
> Does anybody know how Ublox maps their reported PRNs for Galileo and
> Beidou satellites to the true satellite PRNs. What little there is
> on the web appears on the web is rather incorrect.
Depends a LOT on your u-blox firmware ve
A little Googling found a two page datasheet. It doesn't tell you much
more than what you already found out, but does have specifications.
I can't figure out the correct link to include here, but a Google search
with the string "ATiMe-s 38.88" (don't include the quotes) should bring
up the li
The "new" Z12 from Ebay came in today. Works fine (except bad memory backup
batteries). So antenna, power supply, cables are OK. Replacing the memory
backup batteries is fairly easy, except for the gazillion and three screw to
open it up. A pair of memory batteries costs around $15.
I ne
Hello,
I'm looking for a schematic and/or service manual for a Datametrics
SP-100, a 1970s-era rack-mount IRIG time code generator. According to
the Time Nuts archives, Dave Brown (ZL3FJ) was looking for this
information back in 2005 but as far as I can see received no reply. I
have found r
Hi
The big chip with the sticker on it is an Altera FPGA. A picture of the back
side might help a little (if there is anything on the back side …).
Simple answer - it’s a nice source of parts ….
Bob
> On May 11, 2018, at 7:16 PM, CubeCentral wrote:
>
> Hello All!
>
>
>
> I would like to en
Hi
Given the frequency of the oscillator, it’s some sort of sync module for a
telecom system. What data rate and what sort of coding …. who knows …
Bob
> On May 11, 2018, at 7:16 PM, CubeCentral wrote:
>
> Hello All!
>
>
>
> I would like to enlist your help in identifying this "surplus Tim
Hello All!
I would like to enlist your help in identifying this "surplus Timing
Module": https://imgur.com/a/Psw8gP7
All the hints I've been given are:
- Purchased about a decade ago
- Might use a Motorola DSP as the processor
A quick google search lead me to a possible description:
Does anybody know how Ublox maps their reported PRNs for Galileo and Beidou
satellites to the true satellite PRNs. What little there is on the web
appears on the web is rather incorrect.
For Galileo I have seen Ublox PRNs from 212 to 240. That seems to imply it
might be ACTUAL = UBLOX_PRN
Hi,
On 05/11/2018 05:35 PM, Bob kb8tq wrote:
> Hi
>
> If you do the weighted average as indicated in the paper *and* compare it to
> a “single sample” computation,
> the results are different for that time interval. To me that’s a problem. To
> the authors, the fact that the rest of
> the curv
HI
> On May 11, 2018, at 3:12 PM, Magnus Danielson
> wrote:
>
> Hi Don,
>
> On 05/10/2018 02:59 PM, Don Murray via time-nuts wrote:
>> Hi Magnus...
>>
>>
>> Appreciate any help!
>>
>> I participate in the ARRL Frequency Measuring Test,
>> and I would like to automate the measuring proces
Hi Don,
On 05/10/2018 02:59 PM, Don Murray via time-nuts wrote:
> Hi Magnus...
>
>
> Appreciate any help!
>
> I participate in the ARRL Frequency Measuring Test,
> and I would like to automate the measuring process.
>
> I have two frequencies, A and B...
>
> A is a GPS locked HP 3336B se
If want to exploit what the 5372A can do in FMT-context, you should
feed it the amplified and band-pass filtered RF (rather than some
down-converted and otherwise mangled version of the signal) and
capture timing of the actual zero-crossings and post-process that.
--
Poul-Henning Kamp
Oleg,
On 05/11/2018 04:42 PM, Oleg Skydan wrote:
> Hi
>
> --
> From: "Bob kb8tq"
>> The most accurate answer is always “that depends”. The simple answer
>> is no.
>
> I have spent the yesterday evening and quite a bit of the night :)
> reading man
When I was working at the Arecibo Observatory and we were running the
ionospheric heater
at 5.1 MHz (think Mini-HAARP), I'd sometimes go home (about 3 miles away)
and listen to the
signal there.There was frequently substantial random fading of the
signal, suggesting that I
was hearing the vecto
Hi
Well, having actually run FMT virtually “in the back yard” of the transmitting
station …. it’s surprising
what 70 miles will do. In this case, back yard really does mean on the
premises. There is a lot that
gets into even fairly sort distance propagation.
Bob
> On May 11, 2018, at 1:52 P
By the way, if you would like some data captured during the last run, let me
know. I have an excel sheet of the peak data from spectrum lab centered on
1850hz as I use the 3586B receiver.
Regards,
Jerry
Jerry Hancock
je...@hanler.com
(415) 215-3779
> On May 11, 2018, at 10:52 AM, Jerry Hanc
I've had one of the cheap TruePosition GPSDOs running here for the past week,
this is the earlier version with the Bliley oscillator, and as Mark reported
have been seeing what I consider to be excessive holdover reports from Lady
Heather.
At 55 degrees north the number of Sats visible can be a
If you were in Connie’s back yard or had a very stable ground wave, then yes,
you could automate the testing.
There are a number of challenges with this method as looking at the data with a
simple graph will tell. You might have large fluctuations on the high
frequency side only, for instance,
On Fri, May 11, 2018 at 12:57 PM, Adrian Godwin wrote:
> Next thursday :
>
> https://www.eventbrite.co.uk/e/national-physical-laboratory-open-house-2018-prepare-to-be-amazed-tickets-42330306085
If any other Time Nuts are going, it might be amusing to meet up.
Cheers
_
Hi Mark:
I've found there are two main reasons older equipment stops working.
1. A metal to metal joint that's supposed to be conductive is not. See Hints &
Tips: What Goes Wrong:
http://www.prc68.com/I/HaT.shtml#Wgw
The fix is simply to disassemble, cycle all joints a few times and reassemble.
Check TWO things.
1.) Has the RS-232 level converter (1488/1489, MAX232, etc.) failed?
2.) What MODE is your Z3816A, SCPI? The GPSCon software places Z3816A into
SCPI.
This is discussed in K8CU’s notes, below:
K8CU Notes - HP Z3816A GPS Frequency Standard Receiver
https://www.realhamradio.co
Hi Dana,
On 05/10/2018 06:17 PM, Dana Whitlow wrote:
> I'm a bit fuzzy, then, on the definition of ADEV. I was under the
> impression that one measured a series of
> "phase samples" at the desired spacing, then took the RMS value of that
> series, not just a single sample,
> as the ADEV value.
Y
Oleg,
On 05/10/2018 10:46 AM, Oleg Skydan wrote:
> Hi
>
> Now I have some questions. As you know I am experimenting with the
> counter that uses LR calculations to improve its resolution. The LR data
> for each measurement is collected during the gate time only, also
> measurements are continuous
Antenna is good... it is feeding an HP amplified splitter which goes to 7 other
receivers.
And yes, it died in the middle of a run.
I have another Z12 coming from Ebay...
--
> Rats. Is the antenna known to be good? Is the Z12 providing bias on the
antenna cable? Did the Z12
Hi
If you do the weighted average as indicated in the paper *and* compare it to a
“single sample” computation,
the results are different for that time interval. To me that’s a problem. To
the authors, the fact that the rest of
the curve is the same is proof that it works. I certainly agree that
How about measuring variations in propagation delay for WWV on various
frequencies, or WWVB,
using GPS ticks as a reference.
DanaK8YUM
On Fri, May 11, 2018 at 9:41 AM, Van Horn, David <
david.vanh...@backcountryaccess.com> wrote:
>
> Measuring the speed of light (Fizeau or Michelson method?
Hi
--
From: "Bob kb8tq"
The most accurate answer is always “that depends”. The simple answer is
no.
I have spent the yesterday evening and quite a bit of the night :) reading
many interesting papers and several related discussions in the time-n
Measuring the speed of light (Fizeau or Michelson method? Other ways)
I saw a great demo of this at the Exploratorium in SF. They had a long spool
of fiber optic, a disc with holes, and a light source. When static, if the
light shines through the hole in the disc into the fiber, then you can
On 11/05/2018 07:23, jimlux wrote:
On 5/10/18 9:55 PM, Hal Murray wrote:
A few months ago, I was a judge for the county level middle school
science
fair. (I'm not very good at what they wanted, but that's a different
problem.)
What sort of interesting time related experiments can a middle s
Hi
NTP time offsets through various phases of the distribution process …..
Bob
> On May 11, 2018, at 12:55 AM, Hal Murray wrote:
>
>
> A few months ago, I was a judge for the county level middle school science
> fair. (I'm not very good at what they wanted, but that's a different
> problem
Hi how about frequency difference /temperature of a oved'ed Xtal oscillator
-Original Message-
From: time-nuts [mailto:time-nuts-boun...@febo.com] On Behalf Of Bill
Hawkins
Sent: 11 May 2018 06:40
To: 'Discussion of precise time and frequency measurement'
Subject: Re: [time-nuts] Anybody
I am getting some very peculiar behavior with the serial interface on
my GPS rcvr (Z3816A).
I have tried several computers and several different GPS utilities
(GPS-DOS2, Sat Stat, GpsCon, etc.).
To date, the only thing that works is Sat Stat on a windows 2000 computer.
I am using a Null modem and
Next thursday :
https://www.eventbrite.co.uk/e/national-physical-laboratory-open-house-2018-prepare-to-be-amazed-tickets-42330306085
___
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On 5/10/18 9:55 PM, Hal Murray wrote:
A few months ago, I was a judge for the county level middle school science
fair. (I'm not very good at what they wanted, but that's a different
problem.)
What sort of interesting time related experiments can a middle school geek do?
Borrowing serious gear
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