On 7/13/22 5:24 AM, Dan Kemppainen via time-nuts wrote:
Erik,
Just a thought. The 7805 in your schematic appears to be a big part of
the signal chain. I've run into issues with 78xx series regulators
being noisy. Spent a few weeks chasing down noise issues in some
equipment and the 78xx
On 7/12/22 3:51 PM, ed breya via time-nuts wrote:
I forgot to mention that you should also consider possible effects
from the RF present, on the LNA. This can be more significant than
SMPS frequencies getting where they don't belong, especially since the
RF is intentionally right at the
On 7/12/22 8:53 AM, Erik Kaashoek via time-nuts wrote:
I'm struggling with the noise floor.
First tests where done with a 5nV/sqrt(Hz) opamp. Noise floor with
shorted mixer output at 10kHz was -140dBc/Hz. Then I tried with
1nV/sqrt(Hz) opamp, but that made no difference, noise floor at 10kHz
On 7/10/22 4:19 PM, skipp Isaham via time-nuts wrote:
Hello to the Group,
I'd like to get some opinions and war stories regarding GPS reliability at
high RF level and elevation locations.
Background: Three different hill-top GPS receivers, all different types, using
different antennas mounted
On 7/10/22 9:07 AM, Bob kb8tq via time-nuts wrote:
Hi
Yes it is a pain to implement dual supplies. I ponder that issue every time
I build one of these setups. I’ve built a lot of them …. If you are going to
do a single supply, setting up a “virtual ground” is probably the best way
to go. Do it
On 7/7/22 8:55 AM, Bob kb8tq via time-nuts wrote:
Hi
Yes, you do need to know the system gain. Since we are talking about
gain at audio, measuring the gain directly is not a crazy thing to do. One
of the things that makes audio spectrum analyzers a nice tool for this that
they eliminate the
On 6/20/22 2:39 AM, Magnus Danielson via time-nuts wrote:
So, a counter is really like an ADC for phase, with wide bandwidth
input and a sub-sampling mechanism (trigger/time-base). Through
processing frequency estimates can be provided. Aliasing occurrs in
the sub-sampling. Modern counters
On 6/12/22 6:30 PM, Bob kb8tq via time-nuts wrote:
Hi
Tear into some of your SC cut based OCXO’s. Take a look at the crystal package.
For
bonus points, open up the crystal package. If you have the gear to test it,
take a look
at what the gas *is* inside the package. ( Good luck with that :)
On 6/10/22 1:57 PM, Dr. David Kirkby wrote:
On Fri, 10 Jun 2022 at 17:39, Lux, Jim via time-nuts
wrote:
On the subject of rapid warm up. I suppose if you had a need, one
could
dump as much power as you need into the heater. Turn on oscillator,
lights in room dim for a few
On 6/10/22 12:13 PM, Richard (Rick) Karlquist wrote:
I think there is a severe misunderstanding of this issue.
First of all, "rapid warmup" is a red herring. The real
issue is "rapid frequency stabilization".
Indeed. But to a certain extent, that's why oscillators don't have 5
second warm up
On 6/9/22 8:53 PM, Bob kb8tq via time-nuts wrote:
Hi
There happen to be *some* AT cut based OCXO’s that beat the typical
SC cut on warmup … just saying …. :)
Bob
On the subject of rapid warm up. I suppose if you had a need, one could
dump as much power as you need into the heater. Turn on
On 5/31/22 3:23 AM, Carsten Andrich via time-nuts wrote:
On 31.05.22 01:10, glen english LIST via time-nuts wrote:
Be aware not to confuse the antenna ground plane (the patch will
always have its own plane because the top metalization must be fed
against a plane or counterpoise - and a
On 5/26/22 8:18 AM, Bob kb8tq via time-nuts wrote:
Hi
The real answer to the problem is to dig into the bowels of 1940’s electronic
craft.
There are various methods for setting up an L/C filter. You short this / open
that sweep
to find a dip or a peak. You move it to the “right” place. Just
On 5/26/22 8:24 AM, Richard (Rick) Karlquist wrote:
The tweezers are really good *only* for single components - even if they
come with test leads, that's for measuring something like a motor start
capacitor.
I tried using tweezers (cheap ones to be sure) to measure a moderately
complex
On 5/25/22 3:16 PM, ed breya via time-nuts wrote:
Thanks Mike, for info on LCR alternatives. It's good to know of others
out there, if needed. I have an HP4276A and HP4271A. The 4276A is the
main workhorse for all part checking, since it has a wide range of
LCZ, although limited frequency
On 5/16/22 8:11 AM, g...@hoffmann-hochfrequenz.de wrote:
Am 2022-05-16 15:16, schrieb Robert LaJeunesse:
FYI there are some rather flat video filter ICs that have been made in
the past. The 6th order HMC1023LP5E is tunable, at its 28MHz setting
its flat then down 0.1dB in the teens, down 0.35dB
On 5/12/22 2:48 PM, Gary Woods wrote:
On Thu, 12 May 2022 12:01:48 -0600, you wrote:
I've found that corridor discussions have included redefinition of
SI-second, quantum computers, optical clocks, security on PTP clocks,
time-scale algorithms, uncertainty of different measures. Oh, and I just
On 5/11/22 11:50 PM, Matthias Welwarsky wrote:
Dear list members,
My DIY GPSDO has a rather well defined dependence to the environmental
temperature, which correlates almost linearly with a frequency shift of the
OCXO. However, at times I see the error against the GNSS reference increasing
with
https://www.ion.org/publications/abstract.cfm?articleID=13963
Also here: https://ntrs.nasa.gov/citations/20060030427
Download it from JPL here:
https://trs.jpl.nasa.gov/handle/2014/11024
time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe send an email to
On 5/3/22 1:57 AM, Matthias Welwarsky wrote:
Magnus, Jim - thanks a lot. Your post encouraged me to look especially into
flicker noise an how to generate it in the time domain. I now use randn() and
a low-pass filter. Also, I think I understood now how to create phase vs
frequency noise.
On 5/2/22 7:03 PM, Magnus Danielson via time-nuts wrote:
Hi Jim,
Thanks for the corrections. Was way to tired to get the uniform and
normal distributions right.
rand() is then by classical UNIX tradition is generated as a unsigned
integer divided by the suitable (32th) power of two, so the
On 5/2/22 6:09 PM, Magnus Danielson via time-nuts wrote:
Matthias,
On 2022-05-02 17:12, Matthias Welwarsky wrote:
Dear all,
I'm trying to come up with a reasonably simple model for an OCXO that
I can
parametrize to experiment with a GPSDO simulator. For now I have the
following
matlab
On 4/26/22 1:31 PM, ASSI wrote:
On Montag, 25. April 2022 18:27:01 CEST André Balsa wrote:
A PDF of Shera's article can be found here (many thanks to whomever is
hosting this file):
https://www.qsl.net/n9zia/wireless/QST_GPS.pdf
To me, there is no doubt Shera's original design inspired all
On 4/19/22 2:53 AM, Markus Kleinhenz via time-nuts wrote:
Hello Carsten,
thats quite the set of requirements you got there.
I believe you will have a hard time finding a COTS solution that fits
most of your requirements.
You will likely have to split your signal chain into multiple devices:
On 4/14/22 3:00 PM, ed breya wrote:
It depends on context and your definition of low noise. I was
picturing ones commensurate with the 1/f discussion, trying to get
down toward DC. Many are spec'd for so many nV or uV p-p over 0.1 to
10 Hz. The OP-07 is a good example of this class.
A lot of
On 4/14/22 9:54 AM, ed breya wrote:
The low noise opamps are indeed designed for the feature, and they
tell you about it, and how and why. The trade-offs are usually input
bias current being quite high (due to bigger or paralleled transistors
running at fairly high currents), and only good for
On 4/10/22 2:50 AM, Leon Pavlovic wrote:
What would be a (very) good lab setup for the 1/f noise evaluation? I'm
talking about BJTs and JFETs.
What instrumentation and power supply are needed? How not to measure in a
wrong way - like 1/f noise in the instrumentation or the power supply
On 4/9/22 10:03 AM, use...@teply.info wrote:
On 09.04.22 15:31, Richard (Rick) Karlquist wrote:
I am seeing a lot of unsupported "theories" about what should be done
to make devices with low 1/f noise. It might be instructive for
everyone
to read Marv Keshner's PhD dissertation (Stanford)
On 4/9/22 6:31 AM, Richard (Rick) Karlquist wrote:
I am seeing a lot of unsupported "theories" about what should be done
to make devices with low 1/f noise. It might be instructive for everyone
to read Marv Keshner's PhD dissertation (Stanford) discussing 1/f noise.
On 4/7/22 3:09 PM, Joseph Gwinn wrote:
This BTULN OCXO looks very good. While they do mention that it
contains its own regulator, no numbers are given, so it's hard to
know what to make of that claim.
I wouldn't assume battery power - but this is where a phone call helps -
they'll be
On 4/3/22 5:09 PM, Bob kb8tq wrote:
Hi
Does the Abricon have an EFC input? If so, rigging up a PLL to lock
122.88 to 10 MHz is probably the best option.
Bob
And what about moving off the board - so you don't have to chase the
temperature swings.
On Apr 3, 2022, at 7:57 PM, Jeff
On 4/2/22 4:47 PM, Joseph Gwinn wrote:
On Sat, 02 Apr 2022 03:27:06 -0400, time-nuts-requ...@lists.febo.com
wrote:
time-nuts Digest, Vol 216, Issue 3
11. Re: Low Phase Noise70 10 MHz bench signal source sought
(Richard (Rick) Karlquist)
Date: Fri, 1 Apr 2022 19:12:07 -0700
From:
On 4/2/22 9:42 AM, Tom Van Baak wrote:
Yes, I believe hp did what you propose in their Santa Clara cesium
test lab. It was an ensemble of selected 10811 oscillators tightly
phase locked to improve short-term stability and phase noise. Rick
might know the details.
During a tour I saw the
On 4/2/22 9:42 AM, Tom Van Baak wrote:
Yes, I believe hp did what you propose in their Santa Clara cesium
test lab. It was an ensemble of selected 10811 oscillators tightly
phase locked to improve short-term stability and phase noise. Rick
might know the details.
During a tour I saw the
On 4/2/22 3:31 AM, Leon Pavlovic wrote:
Hello to all,
as Gerhard already mentioned, the 1/f data of transistors is really a
kind-of black magic stuff and almost never present in the datasheets.
Not only that, but it potentially changes from lot to lot.
Lately, I've been seeing papers using
On 4/1/22 2:12 PM, Joseph Gwinn wrote:
I'm looking for suggestions for AC-powered 10 MHz sinewave laboratory
signal sources with very low phase noise, having a noise floor below
-170 dBc/Hz. Rubidium is desired, but not essential. Reliability
and durability in lab use is essential.
Which
As I re-read Fleming's "You Only Live Twice" last night, which features
a geyser that is "regulated" by a valve of some sort I was intrigued by
this idea:
Can one discipline a geyser to an external source?
a) I assume there's some data somewhere on eruption timing - sure, Old
Faithful is
On 3/31/22 2:40 PM, Bob kb8tq wrote:
Hi
The gotcha of looking at one GPSDO against another is that
the GPS side of things is “common mode” to all of the devices.
Bob
We all know that GPS is "truth" and has no errors, common or otherwise
...
But seriously, three cornered hats work best
On 3/25/22 12:55 PM, Greg Troxel wrote:
paul swed writes:
I thought there was a thread on this a long time ago. Don't seem to find
it. But was Lady Heather usable with the truetime dcxl gps receiver. When I
probe the dc-xl port it doesn't seem like it has atypical nema stream that
would be
On 3/25/22 10:45 AM, jeanmichel.fri...@femto-st.fr wrote:
Thank you all for the very fruitful exchanges and providing the references
I was looking for (by private email).
FYI I indeed tried the brute force search as documented at
https://github.com/oscimp/gr-satre/tree/main/reverse_code
but
On 3/25/22 5:55 AM, jeanmichel.fri...@femto-st.fr wrote:
Dear community,
I am trying to find historical documents describing the pseudo random sequences
used
in the SATRE Two-Way Satellite Time and Frequency Transfer (TWSTFT) modem.
K. Imamura & F. Takahashi (Two Way Time Transfer Via a
On 3/25/22 7:45 AM, Azelio Boriani wrote:
From the paper "PRESENT STATE OF LONG DISTANCE TIME TRANSFER VIA
SATELLITES WITH APPLICATION OF THE MITREX - MODEM", Hartl specifies
that "The PN-code is a truncated maximum length sequence of period
10.000, instead of the 16.383 chips". In the Xilinx
On 3/22/22 5:43 PM, Bill Beam wrote:
You gotta start the clock some time.
0UTC Jan 6, 1980 is when the GPS clock was started.
Do a search on "0UTC Jan 6, 1980" and you will get lots of answers.
regards
Bill NL7F
Oh lots of "GPS zero = 6 Jan 1980 at 0 UTC" answers, but none that had
Hal's
On 3/22/22 5:30 PM, Hal Murray wrote:
j...@luxfamily.com said:
I've been hunting around for the origin of GPS zero - Why is it 0UTC Jan 6,
1980? Is it a subtle joke about "Twelfth Night"? Does it have some useful
properties that "end of year" does not?
GPS weeks start on Sunday. That was
I've been hunting around for the origin of GPS zero - Why is it 0UTC Jan
6, 1980? Is it a subtle joke about "Twelfth Night"? Does it have some
useful properties that "end of year" does not?
___
time-nuts mailing list -- time-nuts@lists.febo.com --
On 3/6/22 1:36 PM, Krishna Makhija wrote:
Hello Tom,
Yes, the GPSDOs are working well. However, when I use each as a reference
to a separate radio, I find there is a slow phase change over time between
said radios. I imagine this is expected since there will always be some
error between two
On 3/6/22 10:48 AM, Bob kb8tq wrote:
Hi
How close are you trying to get?
How far apart are the GPSDO’s?
A “run of the mill” number would be out around 100 ns. A “pretty good”
number is in the 20 ns range. A “crazy good” number would be 2 ns. To
do better than this, you likely would need to go
On 3/2/22 6:00 AM, paul swed wrote:
As Ed stated Switchers feeding switchers can be problematic. What I found I
had to do was put a relay in series with a slight time delay. This allows
the primary switcher to come up and then gets slammed into the secondary
SPS. Could be a fet/transistor
On 3/1/22 12:54 AM, John Moran, Scawby Design wrote:
David - thanks for the reply, but these seem designed for SDR and I wanted
1pps. Nice and cheap though.
Paul - thanks too; it seems that you are saying that the performance of all
GPSDOs are the same, but that wasn't the impression I had
work, but I suspect it would - they're not doing any
exotic protocols - it's just serial data.
And I've never depended on the timing of the messages - so the USB
timing isn't important.
A lot was left unsaid in that simple statement below...
Larry
On 2/24/2022 8:53 PM, Lux, Jim wrote:
On 2
On 2/24/22 7:25 PM, ed breya wrote:
Paul and Hal, I think there may be some confusion here. I modified the
Z3801A to RS-232 way back when I first got it. My recent post was just
discussing some of what's in this demo/testing unit thing. It's just a
translator for TTL/RS-232 for when the GPS RX
On 2/11/22 9:51 AM, Attila Kinali wrote:
Moin,
You might know that I am hosting a copy of the old PTTI papers from
1969 to 2012 on http://time.kinali.ch/ptti/
And thanks to Demetrios Matsakis the set is now complete with all papers from
those years.
There is one catch, though, PTTI 2005 was
On 2/7/22 4:57 PM, Erik E. Fair wrote:
I wonder if the Tonga volcano explosion had measurable effect on the
Earth's rotation, and what that means for UTC leap seconds (or not)
from the IERRS.
Erik
The folks at JPL usually put out a press release if there is an effect,
but it takes a
On 2/7/22 12:46 PM, Kevin Rowett wrote:
Interesting data…
Can someone put the disturbance in perspective? How much would this affect
navigation, or timing, and how large (or small) is this disturbance in
magnitude as compared to other events (CMEs?).
looks like a small single digit
On 2/7/22 6:05 AM, Attila Kinali wrote:
On Mon, 7 Feb 2022 09:51:27 +1100
glen english LIST wrote:
If you are interested in harmonics of the reference frequency at the
input to the phase detector, this will be entirely defined by the
fourier series of the source. Get yourself a 2nd year EE
On 2/5/22 7:00 PM, Martin Flynn wrote:
Since my homemade version did not turn out as well as I had hoped, I
was planning to have my local fab shop laser cut a rack panel for our
"new" LUCENT-SYMMETRICOM Z3810AS (KS24361)
You might also check out frontpanelexpress.com - they do nice engraved
On 1/25/22 9:29 AM, Bob kb8tq wrote:
Hi
It’s not clear that the regs in Australia would care about
doing this in an area not covered by this or that time signal.
I don’t know *what* they do or don’t say. My only concern
is that we all stay out of jail :)
Bob
For test purposes, an improvised
On 1/25/22 7:52 AM, Bob kb8tq wrote:
Hi
I would check the local rules and regs before you put money
into one of these gizmos. At least by the rules over here, this
sort of thing might get you in trouble.
Setting a watch 30 cm away would require *very* low power
At 20m, you'd probably be
On 1/25/22 2:29 AM, Anthony Dunne wrote:
G'day time nut friends
I wonder if one of you could point me in the right direction on how to
purchase (if one exists) a Time Signal Transmitter for use at the
local level (range 20m) for synchronising watches and radio clocks
using the various
On 1/22/22 3:30 PM, ed breya wrote:
I'd vote for going with a transformer too, but not just any old
transformer - I'll explain later.
You can indeed connect directly to line with an AC divider, and
measure the signal. In fact, you can even build a very broad band
probing system that can go
On 1/22/22 9:48 AM, Patrick Barthelow wrote:
Looking to increase accuracy of a microwave transceiver pair designed to
measure very long distances (*up to even 100km, Line of sight)
They send a microwave carrier, modulated by HF radio modulation sine waves.
To an identical Transceiver at the far
On 1/22/22 8:21 AM, Bob kb8tq wrote:
Hi
None of these transformers are designed for audio use. The same is true
of the various inductors and capacitors mounted up on power poles to try
to phase correct the distribution process. Pretty much all of them are “out
in the wild” and thus exposed to
On 1/22/22 2:09 AM, Wilko Bulte wrote:
Given that it sounds that these capacitors are mains connected I would recommend using Y
rated capacitors for safety reasons. That should prevent them from going short circuit, Y
caps being designed to "fail open".
Or did I misunderstand the proposed
rrier current
means you need to pass higher frequencies)
Sent: Friday, January 21, 2022 at 8:48 PM
From: "Lux, Jim"
To: time-nuts@lists.febo.com
Subject: [time-nuts] Re: Another reason to monitor line frequency :) - My AC
measurement project & question
On 1/21/22 4:43 PM, willl
On 1/21/22 4:43 PM, willl will wrote:
Hi everyone,
I have an recently finished project that also measuring AC waveform, full
description here:
https://github.com/will127534/RaspberryPiAtomicNixieClock/wiki
Basically using an AC transformer and Ti's ADC8681 @ 50Khz sampling rate.
This year I'm
On 1/19/22 3:50 PM, Hal Murray wrote:
anders.e.e.wal...@gmail.com said:
AFAIK we only have 10 minute data...
What is the wavelength (in seconds) of an eruption? What's the Nyquist
sampling rate?
From the shock wave? I'm not sure wavelength is the appropriate
measure - a shock wave starts
no ball of
fire time-nuts wise)
On Jan 15, 2022, at 10:01 AM, Lux, Jim wrote:
On 1/14/22 3:40 PM, Bob kb8tq wrote:
Hi
The design traces back to the Efratom “EMXO” from the 1980’s.
Vectron bought the rights to that design and produced examples
of it for about a decade or so.
Bob
I flew
On 1/10/22 9:56 AM, Bob kb8tq wrote:
Hi
An equally important part of this:
What are you driving with this OCXO and what is it’s measured noise floor
at 1 Hz (or 10 Hz or what ever ….). In some cases a “crazy” OCXO is actually
quieter than the device it is driving. That means that the last 5 or
On 1/10/22 7:12 AM, Bernd Neubig wrote:
We are receiving such inquiries from "Audio nuts" rather frequently, but
also from professional high-end audios-studio equipment makers. There
argument is often, that the spatial transparency of the sound, i.e. how
exactly you can locate the sound source
On 1/10/22 12:26 AM, Norman Reitz via time-nuts wrote:
Hi, everyone,
I am looking for suppliers of high-quality OCXO in 10 Mhz (sine / square) and
25 Mhz sine wave output. I can only find changes below my quality requirements
for phase noise at Mouser or Digikey. E.g. a 10Mhz should be better
On 1/2/22 12:39 PM, Peter Vince wrote:
I used to work in broadcast television, and find that most people would
notice a couple of "frames" (80ms here in the UK) - we, trained and looking
for it, would notice one frame (40ms). But it is more disturbing if the
sound is early, as that is so
On 1/2/22 9:57 AM, Hal Murray wrote:
j...@luxfamily.com said:
So the *sound* of the clap has to propagate to the sound recording equipment
(some ten miliseconds away if the mic is on a fishpole or boom).
How far off does the audio have to be before it doesn't look/sound right? How
accurately
On 1/1/22 8:48 PM, Tom Van Baak wrote:
Hal Murray wrote:
> where do you get the time?
The new years celebrations last night remind me of another source of
time: time balls.
Although a bit of nostalgia these days or even a joke, time balls were
clever, precise, and a critical part of naval
On 12/27/21 12:18 PM, Brent wrote:
My understanding (and I could be wrong) is that one could derive 'stellar'
time from a start sight/fix on polaris or another well tracked celestial
object. I was once told that early editions of Bowditch provided the
process (for the moon I was told) although
On 12/15/21 7:53 AM, Magnus Danielson via time-nuts wrote:
Hi,
Expect network routes to be more dispersed these days, as it is needed.
While the wedge plot is a classic for NTP, it may be interesting to
plot forward and backward path histograms independently.
Cheers,
Magnus
I assume
On 12/15/21 7:53 AM, Magnus Danielson via time-nuts wrote:
Hi,
Expect network routes to be more dispersed these days, as it is needed.
While the wedge plot is a classic for NTP, it may be interesting to
plot forward and backward path histograms independently.
Cheers,
Magnus
I assume
On 12/10/21 12:31 PM, Brooke Clarke via time-nuts wrote:
Hi Hal:
There has been some recent research into illusions related to sight
and sound.
https://en.wikipedia.org/wiki/McGurk_effect - related to speech
and search "audio optical illusion"
I like a crisp "tick" for clock human
On 12/10/21 12:09 PM, Hal Murray wrote:
Does anybody have numbers for how long it takes for a visual signal to get
into your brain?
I think it's around 250 ms for a human to push a button when a light goes on.
Less if the penalty for false pushes is low. I don't have a handy URL to back
that
On 12/8/21 2:15 PM, Bill Dailey wrote:
You can also set them up so they don’t write to the SD once everything is set.
SD’s will last forever like this. Basically read only and RAM disk.
yes indeed - these days, with lots o'RAM on a rPi, you should boot off
the SD (or eMMC) and run out of
On 12/6/21 11:34 AM, John Miller via time-nuts wrote:
This is something I have explored from time to time in order to find
a good local display option for Pis running as GIS-disciplined NTP
servers. I've done a lot of exploring and fiddling around with different
options but have yet to find a
On 12/4/21 10:31 AM, Jeff Blaine wrote:
I'm wondering what the modern version of a fixed-frequency oscillator
module is.
I had used the Silicon Labs (now Skyworks) Si570 in the past which has
a great close-in noise footprint - but that requires I2C and some
glue. The Seiko
On 11/29/21 1:57 AM, Hal Murray wrote:
j...@luxfamily.com said:
And a lot ofsources may have a low flat spot in the curve, but it
eventually trends up. Except for primary standards like Cs beam.
What's magic about "primary standard" or "Cs beam" that keeps the ADEV from
trending up?
Their
t also has plots comparing clock stability vs. size and vs. power.
Highly recommended reading.
There is also a power point version with similar content as the paper:
https://www.gps.gov/cgsic/meetings/2019/scherer.pdf
/tvb
On 11/28/2021 2:05 PM, Lux, Jim wrote:
Speaking of which, does anyone h
On 11/28/21 9:37 AM, Bernd Neubig wrote:
-Jim wrote-
I wouldn't actually think there's a Cs on ISS. What purpose would it serve? We as
time-nuts think "of course you'd have a precise source of time", but really,
there's not much need for timing on ISS on a scale smaller than
On 11/28/21 2:11 AM, Andy Talbot wrote:
I would imagine there are already several caesium clocks on board the ISS,
anyway.
Don't forget there is a velocity component in relativistic time shift, as
well as gravitational, so using a moving platform like an aircraft or the
ISS complicated things a
On 11/27/21 11:08 PM, Tom Van Baak wrote:
Hi Thomas,
Good to hear the experiment was contagious for you. If you have
additional questions let me know.
Your suggestion about Mount Evans and Pikes Peak are excellent. You
will enjoy this 2017 paper:
"An Undergraduate Test of Gravitational
On 11/27/21 3:20 PM, Magnus Danielson via time-nuts wrote:
Hi,
There is an overemphasis on the atom being used, and especially on
cesium as that is what is used for SI definition. However, actual
implementation means actual physical devices, and the physical devices
have a physics package,
On 11/27/21 12:37 PM, Thomas Valerio wrote:
I think that Tom's GREAT adventure is kind of what sealed the deal making
me a time-nut or at least a time-nuts lurker, a lot of this stuff is still
little over my head, but I keep reading.
If anyone is inclined and has the clocks and the kids ( I
On 11/27/21 7:33 AM, Andy Talbot wrote:
Just been reading your adventures with 3 Cs clocks, a mountain and 3 kids,
but I can't make the estimate of time dilation work out.
You measured ~ 23ns and say it agrees with calculation
The equation quoted in a related reference, for "low elevations" is
On 11/22/21 7:51 PM, Bill Notfaded wrote:
There's no substitute for a few good rubidiums. OCXO and Rb are
different. It's really hard to beat a really good GNSS diciplined Rb!
Extremely good holdover. We're timenuts after all right? Where's the fun
if you don't try them all? There isn't any
On 11/22/21 10:25 AM, Andy Talbot wrote:
But you don't need a DDS route to get 1 PPS from any frequency that is an
exact multiple of 1Hz.
I clock a PIC with 10MHz from a master reference. An interrupt is
generated at an exact submultiple of this, and additional code outputs a
pulse every 25
On 11/22/21 10:19 AM, Gerhard Hoffmann wrote:
Am 22.11.21 um 18:31 schrieb Erik Kaashoek:
Some time ago I needed a output at 10,00.001Hz so I tried to do
that with a SI5351.
Using pure integer math (as the PLL and divider register are
integers) i search for a combination of 3
On 11/22/21 8:52 AM, Jeremy Elson wrote:
I did not see any such setting in the Rigol, but I'll check again. in April
I did write to Rigol to report the problem and had the following (abridged)
conversation with support:
Me:
"I recently tried to use your DG1022Z signal generator to generate one
On 11/11/21 4:00 PM, djl wrote:
I've used, wait for it, beeswax as a potting compound. Gouda cheese
comes coated with it (some has paraffin, get the best,) in a lovely
red. I also found out some years ago that Catholic churches use pure
beeswax for large (not votive) candles and may give you
On 11/10/21 2:40 PM, Richard (Rick) Karlquist wrote:
I am looking for help choosing a potting compound that
has the following properties:
1. Good for 5,000VAC @ 1 MHz
2. Low RF losses.
3. Low permittivity is preferred
4. Low tempco of permittivity is a want.
5. Something I can implement in
On 11/10/21 5:31 PM, Gerhard Hoffmann wrote:
A customer of mine uses Solitane, another one Mupsil.
I just wrote down the names in case I might need it.
Probably more for coating boards in space apps, no idea
if it fits.
Am 10.11.21 um 23:40 schrieb Richard (Rick) Karlquist:
I am looking for
On 11/10/21 4:37 PM, Brooke Clarke via time-nuts wrote:
Hi Jim:
Be careful with RTVs. Some out gas acid that attacks metal, even gold
plated metal. Guess how I know that.
Oh yes.. one definitely needs to read the data sheets.. RTV12 is 2
part. Most 2 part RTVs don't use acid. And the
On 11/10/21 2:40 PM, Richard (Rick) Karlquist wrote:
I am looking for help choosing a potting compound that
has the following properties:
1. Good for 5,000VAC @ 1 MHz
2. Low RF losses.
3. Low permittivity is preferred
4. Low tempco of permittivity is a want.
5. Something I can implement in
On 11/10/21 7:29 AM, Bob kb8tq wrote:
Hi
Your GPS antenna does not have a clue where signals are coming from. The only
way things get plotted is based on the almanac data. If it sees sat Id 21, it
looks in
the almanac for id 21. If the almanac says it’s over India, that’s where it
goes on the
On 11/5/21 11:32 AM, Andy Talbot wrote:
Use FTDI USB serial ports - you can't go wrong with them.
https://ftdichip.com/
I have, at the last count, used something like 200 of their FT232 device in
one form or another on the shack PC. I know that, because device manager
has registered up to
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