As there a hobby application of precise time or frequency measurement except for being a time nut?
Our group (K6MTU) run one of the world wide HF DX propagation beacons, which are
all synced in assigned time slots around the planet. GPS derived. But we
are talking slots in seconds, not nS sync. Credit goes to Kevin Rowett K6TD for building
this. https://www.ncdxf.org/beacon/ I know the ARRL runs a precise
freq test on an assigned schedule too, down to some fractional Hz, which is useful for things like
FT8/JT64 et al (look up Joe Taylor).
and this lash up, we sync/split time slots within each machine, but again, mS
for DMR. https://dmr.wa6ycz.org/ you can get an idea of our sensor networks too.
We sync seismometers against USGS for example. There is a massive sync’d
seismology net here in Calif https://www.cisn.org/ we are trying to join that.
The ham/hobby seismology guys are https://www.seismicnet.com/ all time syncd
tightly.
As hams, we also run a NASA Deep Sky Meteor camera system for meteor
tracking. https://meteorshowers.seti.org/ all NTP syncd.
FYI interesting work going on with
LeoLabs phased array radars, sync’d globally as to
space junk tracking. Alaska vs New Zealand vs Eu and soon mobile. Started
in SRI’s parking lot. Interesting how a ham / research project turned
in to a multi $100M company. All based on precise timing and ranging.
. https://leolabs.space/
Another interesting one is Wayne Rosing’s Las Cumbres Observatory which
runs a global Time Domain Astronomy system, many hams. It is
officially “amateur”, but NSF is now sponsoring some research on event
timing and synchronicity.
https://lco.global/
rgds to all.
g
I have been tinkering around with a wwvb receiver on a teensydino. I feel like it is something that would help me better understand signal processing.
My goal is to better the first lock acquisition of a cheap atomic clock
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On Apr 11, 2025, at 06:56, Erik Kaashoek via time-nuts <time-nuts@lists.febo.commailto:time-nuts@lists.febo.com> wrote:
Maybe the subject line is a bit clickbait but this is a serious question.
Hobby VNA are used to measure impedance for antenna, amplifiers,
filters, PCB's and cables. Many applications for a VNA outside the
professional world.
Hobby spectrum analyzers are user for hunting RFI, measuring harmonics
of active devices, assessing what part of the spectrum is still
available for wireless devices, etc... Again many applications.
But for time and frequency measurement the situation seems to be
different. What are hobby applications for accurate assessment of
stability, time or frequency?
For radio amateurs that operate in the GHz bands the accurate assessment
of the frequencies of their generators is such an application but what
other applications do exist and what are their requirements regarding
accuracy?
I'm purposely excluding the applications where the accuracy is the goal
instead of some usage for accuracy.
Any input is welcome.
Erik.
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for fun and verification of the common source I built a a phase
comparation circuit for a GPS derived 60kHz and the WWVb, you could see
how the propagation time is changing while the sun is moving
73 KO6exs
Alex
On 4/13/2025 12:38 PM, chris elfpen.com via time-nuts wrote:
I have been tinkering around with a wwvb receiver on a teensydino. I feel like it is something that would help me better understand signal processing.
My goal is to better the first lock acquisition of a cheap atomic clock
Get BlueMail for Androidhttps://bluemail.me
On Apr 11, 2025, at 06:56, Erik Kaashoek via time-nuts <time-nuts@lists.febo.commailto:time-nuts@lists.febo.com> wrote:
Maybe the subject line is a bit clickbait but this is a serious question.
Hobby VNA are used to measure impedance for antenna, amplifiers,
filters, PCB's and cables. Many applications for a VNA outside the
professional world.
Hobby spectrum analyzers are user for hunting RFI, measuring harmonics
of active devices, assessing what part of the spectrum is still
available for wireless devices, etc... Again many applications.
But for time and frequency measurement the situation seems to be
different. What are hobby applications for accurate assessment of
stability, time or frequency?
For radio amateurs that operate in the GHz bands the accurate assessment
of the frequencies of their generators is such an application but what
other applications do exist and what are their requirements regarding
accuracy?
I'm purposely excluding the applications where the accuracy is the goal
instead of some usage for accuracy.
Any input is welcome.
Erik.
time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe send an email to time-nuts-leave@lists.febo.com
time-nuts mailing list -- time-nuts@lists.febo.com
To unsubscribe send an email to time-nuts-leave@lists.febo.com
Hey Mike,
I was using WXTOIMG software but on the 136.5MHz frequencies to capture images from these polar orbiters. I used a home built Quadrifilar Helix antenna (QFH) and an ICOM PCR-1000 @50KHz bandwidth to receive the signals. I think the last image I captured was 15 years ago. With GOES, I think the polar orbiters are going obsolete and not being replaced.
Bob
-----Original Message-----
From: Mike via time-nuts time-nuts@lists.febo.com
Sent: Saturday, April 12, 2025 8:25 AM
To: time-nuts@lists.febo.com
Cc: Mike mpb45@clanbaker.org
Subject: [time-nuts] Re: A hobby application of precise time or frequency
Importance: High
Hello, Time-nutters-
A hobby of mine is downloading imagery from the several NOAA polar-orbit environmental satellites.
These satellites are in a relatively low orbital altitude of just a few hundred miles. Their downlink frequency is just under 2 Ghz. Their orbital period is just under 95 minutes. I track these birds with an elevation over azimuth 2 meter parabolic dish antenna which at that frequency has a half-power beamwidth of just under 2 degrees. Tracking them requires a relatively accurate time clock. A time error of just a couple of seconds will result in loss of signal. If you are interested I can send a photo of my home-brewed tracking mount.
Mike Baker Micanopy, Florida (just a few miles south of Gainesville, Florida.
On 4/11/2025 6:46 AM, Erik Kaashoek via time-nuts wrote:
Maybe the subject line is a bit clickbait but this is a serious question.
Hobby VNA are used to measure impedance for antenna, amplifiers,
filters, PCB's and cables. Many applications for a VNA outside the
professional world.
Hobby spectrum analyzers are user for hunting RFI, measuring harmonics
of active devices, assessing what part of the spectrum is still
available for wireless devices, etc... Again many applications.
But for time and frequency measurement the situation seems to be
different. What are hobby applications for accurate assessment of
stability, time or frequency?
For radio amateurs that operate in the GHz bands the accurate
assessment of the frequencies of their generators is such an
application but what other applications do exist and what are their
requirements regarding accuracy?
I'm purposely excluding the applications where the accuracy is the
goal instead of some usage for accuracy.
Any input is welcome.
Erik.
time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe send an email to time-nuts-leave@lists.febo.com
On 15/04/2025 00:10, rbenward--- via time-nuts wrote:
Hey Mike,
I was using WXTOIMG software but on the 136.5MHz frequencies to capture images from these polar orbiters. I used a home built Quadrifilar Helix antenna (QFH) and an ICOM PCR-1000 @50KHz bandwidth to receive the signals. I think the last image I captured was 15 years ago. With GOES, I think the polar orbiters are going obsolete and not being replaced.
Bob
Actually the next generation of polar orbiters are due to be launched starting
this year. More information:
https://www.eumetsat.int/metop-sg
The newest 137 MHz orbiters are using digital image transmission to obtain about
ten times the ground resolution and more channels.
https://usradioguy.com/meteor-satellite/
Cheers,
David
SatSignal Software - Quality software for you
Web: https://www.satsignal.eu
Email: davidtaylor@writeme.com
BlueSky: @gm8arv.bsky.social, Twitter: @gm8arv
I was using WXTOIMG software but on the 136.5MHz frequencies to capture images from these polar
orbiters. I used a home built Quadrifilar Helix antenna (QFH) and an ICOM PCR-1000 @50KHz bandwidth
to receive the signals. I think the last image I captured was 15 years ago. With GOES, I think the
polar orbiters are going obsolete and not being replaced.
Bob
Actually the next generation of polar orbiters are due to be launched starting this year. More
information:
GOES (or any geostationary satellite) can only image with reasonable resolution up to /-60 degree
latitude, whereas polar regions are fundamental information for modelling weather patterns.
The newer digital polar weather satellite decoding is a bit more involved than the POES analog signals
http://jmfriedt.free.fr/glmf_meteor_eng.pdf but do provide opportunities for spaceborne LEO time
transfer opportunities.
Best, Jean-Michel
OK, I feel better. My images are no worse than yours. I always wondered
how people get those clear top to bottom images. Apparently, it's not so
easy.
Bob
-----Original Message-----
From: David Taylor via time-nuts time-nuts@lists.febo.com
Sent: Tuesday, April 15, 2025 2:33 AM
To: time-nuts@lists.febo.com
Cc: David Taylor david-taylor@blueyonder.co.uk
Subject: [time-nuts] Re: A hobby application of precise time or frequency
Importance: High
On 15/04/2025 00:10, rbenward--- via time-nuts wrote:
Hey Mike,
I was using WXTOIMG software but on the 136.5MHz frequencies to capture
images from these polar orbiters. I used a home built Quadrifilar Helix
antenna (QFH) and an ICOM PCR-1000 @50KHz bandwidth to receive the signals.
I think the last image I captured was 15 years ago. With GOES, I think the
polar orbiters are going obsolete and not being replaced.
Bob
Actually the next generation of polar orbiters are due to be launched
starting this year. More information:
https://www.eumetsat.int/metop-sg
The newest 137 MHz orbiters are using digital image transmission to obtain
about ten times the ground resolution and more channels.
https://usradioguy.com/meteor-satellite/
Cheers,
David
SatSignal Software - Quality software for you
Web: https://www.satsignal.eu
Email: davidtaylor@writeme.com
BlueSky: @gm8arv.bsky.social, Twitter: @gm8arv
time-nuts mailing list -- time-nuts@lists.febo.com To unsubscribe send an
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