EK
Erik Kaashoek
Fri, Apr 11, 2025 10:46 AM
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.
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.
DW
Dana Whitlow
Fri, Apr 11, 2025 12:29 PM
There are the HAMSCI measurements of path delay variations due to solar
eclipses
amd various other causes.
Dana
On Fri, Apr 11, 2025 at 6:57 AM Erik Kaashoek via time-nuts <
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
There are the HAMSCI measurements of path delay variations due to solar
eclipses
amd various other causes.
Dana
On Fri, Apr 11, 2025 at 6:57 AM Erik Kaashoek via time-nuts <
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
>
BC
Bob Camp
Fri, Apr 11, 2025 1:23 PM
Hi
I’d say that the most common things that pop up here on a regular basis are:
-
I have a stand alone frequency source (XO,TCXO,OCXO,Rb,Cesium,Maser ….) that I bought from (fill in the blank) and I want to see if it works properly.
-
I’ve decided to set up a time server (NTP or something else) and I want to check it out.
-
I’ve bought a GPSDO and want to check it out.
-
I have a mechanical clock (yes the do exist) and want to see how it does
-
I’m monitoring the phase of the local power grid.
-
I’ve decided to design and/or build from scratch items 1, 2, 3 or 4
No, that’s not an exhaustive list. I think it’s enough for right now.
What you need is going to depend a lot on which of those rabbit holes you head down. Inevitably the first step is a “reference source” that is better than (or at least as good as) your “target”. Even there the “better than” depends on what characteristic of the target you are looking at. Then the measurement approach comes in.
Many many many rabbit holes to wander down. Each one of them is a bit unique.
Bob
On Apr 11, 2025, at 6:46 AM, Erik Kaashoek via time-nuts 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
Hi
I’d say that the most common things that pop up here on a regular basis are:
1) I have a stand alone frequency source (XO,TCXO,OCXO,Rb,Cesium,Maser ….) that I bought from (fill in the blank) and I want to see if it works properly.
2) I’ve decided to set up a time server (NTP or something else) and I want to check it out.
3) I’ve bought a GPSDO and want to check it out.
4) I have a mechanical clock (yes the do exist) and want to see how it does
5) I’m monitoring the phase of the local power grid.
6) I’ve decided to design and/or build from scratch items 1, 2, 3 or 4
No, that’s not an exhaustive list. I think it’s enough for right now.
What you need is going to depend a *lot* on which of those rabbit holes you head down. Inevitably the first step is a “reference source” that is better than (or at least as good as) your “target”. Even there the “better than” depends on what characteristic of the target you are looking at. Then the measurement approach comes in.
Many many many rabbit holes to wander down. Each one of them is a bit unique.
Bob
> On Apr 11, 2025, at 6:46 AM, Erik Kaashoek via time-nuts <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
J
john@miles.io
Fri, Apr 11, 2025 5:06 PM
You build good sources so that you have something to measure.
You build good instruments so that you can measure good sources.
You do these things not because they are easy, but because you thought they would be easy. This is the Tao of Time and Frequency. 😊
-- john
-----Original Message-----
From: Erik Kaashoek via time-nuts time-nuts@lists.febo.com
Sent: Friday, April 11, 2025 3:46 AM
To: time nuts time-nuts@lists.febo.com
Cc: Erik Kaashoek erik@kaashoek.com
Subject: [time-nuts] As there a hobby application of precise time or frequency measurement except for being a time nut?
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
You build good sources so that you have something to measure.
You build good instruments so that you can measure good sources.
You do these things not because they are easy, but because you thought they would be easy. This is the Tao of Time and Frequency. 😊
-- john
-----Original Message-----
From: Erik Kaashoek via time-nuts <time-nuts@lists.febo.com>
Sent: Friday, April 11, 2025 3:46 AM
To: time nuts <time-nuts@lists.febo.com>
Cc: Erik Kaashoek <erik@kaashoek.com>
Subject: [time-nuts] As there a hobby application of precise time or frequency measurement except for being a time nut?
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
JL
Jim Lux
Fri, Apr 11, 2025 5:26 PM
A lot depends on what you consider "precise" of course...
Radio astronomy - more and more people (yeah, probably < 1/2 dozen, but..) are setting up interferometers and precise time knowledge is important.
Radio amateurs on microwave frequencies with narrow band signals need good frequency control (1ppm at 10 GHz is wildly insufficient - you'd like to be within 10 Hz - 1E-9)
There seems to be a bunch of people doing direction finding with a distributed system (perhaps collaborative drone flight) - it's unclear what their requirements are.
There is a hobby radar community with bistatic radars - both at low frequencies (chirp sounders) and at microwave frequencies. The performance of the radar depends on both long term stability (for SAR) and closein (phase noise).
I know a guy with a LTE base station he built in his house - granted he's not putting up multiples, so he doesn't need precise timing (yet).
I suspect none of these are hundreds or thousands of people, but they all have some need to understand time and frequency to a "more than you get with a TinySA or oscilloscope" kind of performance.
On Fri, 11 Apr 2025 12:46:12 +0200, Erik Kaashoek via time-nuts 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
A lot depends on what you consider "precise" of course...
Radio astronomy - more and more people (yeah, probably < 1/2 dozen, but..) are setting up interferometers and precise time knowledge is important.
Radio amateurs on microwave frequencies with narrow band signals need good frequency control (1ppm at 10 GHz is wildly insufficient - you'd like to be within 10 Hz - 1E-9)
There seems to be a bunch of people doing direction finding with a distributed system (perhaps collaborative drone flight) - it's unclear what their requirements are.
There is a hobby radar community with bistatic radars - both at low frequencies (chirp sounders) and at microwave frequencies. The performance of the radar depends on both long term stability (for SAR) and closein (phase noise).
I know a guy with a LTE base station he built in his house - granted he's not putting up multiples, so he doesn't need precise timing (yet).
I suspect none of these are hundreds or thousands of people, but they all have some need to understand time and frequency to a "more than you get with a TinySA or oscilloscope" kind of performance.
On Fri, 11 Apr 2025 12:46:12 +0200, Erik Kaashoek via time-nuts <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
MA
Martin A Flynn
Sat, Apr 12, 2025 12:42 AM
A lot depends on what you consider "precise" of course...
Radio astronomy - more and more people (yeah, probably < 1/2 dozen, but..) are setting up interferometers and precise time knowledge is important.
Radio amateurs on microwave frequencies with narrow band signals need good frequency control (1ppm at 10 GHz is wildly insufficient - you'd like to be within 10 Hz - 1E-9)
There seems to be a bunch of people doing direction finding with a distributed system (perhaps collaborative drone flight) - it's unclear what their requirements are.
There is a hobby radar community with bistatic radars - both at low frequencies (chirp sounders) and at microwave frequencies. The performance of the radar depends on both long term stability (for SAR) and closein (phase noise).
I know a guy with a LTE base station he built in his house - granted he's not putting up multiples, so he doesn't need precise timing (yet).
I suspect none of these are hundreds or thousands of people, but they all have some need to understand time and frequency to a "more than you get with a TinySA or oscilloscope" kind of performance.
On Fri, 11 Apr 2025 12:46:12 +0200, Erik Kaashoek via time-nuts 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
Radio astronomy - Check...
Radio amateurs - check...
https://isec.space/wp-content/uploads/2025/02/IMG_0179.jpeg
https://isec.space/wp-content/uploads/2025/04/tlm_18_lens_flare-1024x724-1.jpg
And looking for a decent cesium clock...
Martin
On 4/11/2025 1:26 PM, Jim Lux via time-nuts wrote:
> A lot depends on what you consider "precise" of course...
>
> Radio astronomy - more and more people (yeah, probably < 1/2 dozen, but..) are setting up interferometers and precise time knowledge is important.
>
> Radio amateurs on microwave frequencies with narrow band signals need good frequency control (1ppm at 10 GHz is wildly insufficient - you'd like to be within 10 Hz - 1E-9)
>
> There seems to be a bunch of people doing direction finding with a distributed system (perhaps collaborative drone flight) - it's unclear what their requirements are.
>
> There is a hobby radar community with bistatic radars - both at low frequencies (chirp sounders) and at microwave frequencies. The performance of the radar depends on both long term stability (for SAR) and closein (phase noise).
>
> I know a guy with a LTE base station he built in his house - granted he's not putting up multiples, so he doesn't need precise timing (yet).
>
> I suspect none of these are hundreds or thousands of people, but they all have some need to understand time and frequency to a "more than you get with a TinySA or oscilloscope" kind of performance.
>
>
>
> On Fri, 11 Apr 2025 12:46:12 +0200, Erik Kaashoek via time-nuts <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
JG
Jeff Geerling
Sat, Apr 12, 2025 1:16 AM
Speaking for myself, as a noob to this list, I've seen all these time-related things and never understood how they work.
Especially in media (AES67, SMPTE 2110, genlock, etc) and science, it seems like aspects of time are only growing more important year over year.
If we don't know the fundamentals, how can we advance?
It's also a lot cheaper than cars, guns, etc. (at least that's what I tell myself as I look at masers and old HP gear on eBay...)
-Jeff Geerling
On Apr 11, 2025, at 6:20 PM, Jim Lux via time-nuts time-nuts@lists.febo.com wrote:
A lot depends on what you consider "precise" of course...
Radio astronomy - more and more people (yeah, probably < 1/2 dozen, but..) are setting up interferometers and precise time knowledge is important.
Radio amateurs on microwave frequencies with narrow band signals need good frequency control (1ppm at 10 GHz is wildly insufficient - you'd like to be within 10 Hz - 1E-9)
There seems to be a bunch of people doing direction finding with a distributed system (perhaps collaborative drone flight) - it's unclear what their requirements are.
There is a hobby radar community with bistatic radars - both at low frequencies (chirp sounders) and at microwave frequencies. The performance of the radar depends on both long term stability (for SAR) and closein (phase noise).
I know a guy with a LTE base station he built in his house - granted he's not putting up multiples, so he doesn't need precise timing (yet).
I suspect none of these are hundreds or thousands of people, but they all have some need to understand time and frequency to a "more than you get with a TinySA or oscilloscope" kind of performance.
On Fri, 11 Apr 2025 12:46:12 +0200, Erik Kaashoek via time-nuts 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
Speaking for myself, as a noob to this list, I've seen all these time-related things and never understood how they work.
Especially in media (AES67, SMPTE 2110, genlock, etc) and science, it seems like aspects of time are only growing more important year over year.
If we don't know the fundamentals, how can we advance?
It's also a lot cheaper than cars, guns, etc. (at least that's what I tell myself as I look at masers and old HP gear on eBay...)
-Jeff Geerling
> On Apr 11, 2025, at 6:20 PM, Jim Lux via time-nuts <time-nuts@lists.febo.com> wrote:
>
>
>
>
>
>
> A lot depends on what you consider "precise" of course...
>
> Radio astronomy - more and more people (yeah, probably < 1/2 dozen, but..) are setting up interferometers and precise time knowledge is important.
>
> Radio amateurs on microwave frequencies with narrow band signals need good frequency control (1ppm at 10 GHz is wildly insufficient - you'd like to be within 10 Hz - 1E-9)
>
> There seems to be a bunch of people doing direction finding with a distributed system (perhaps collaborative drone flight) - it's unclear what their requirements are.
>
> There is a hobby radar community with bistatic radars - both at low frequencies (chirp sounders) and at microwave frequencies. The performance of the radar depends on both long term stability (for SAR) and closein (phase noise).
>
> I know a guy with a LTE base station he built in his house - granted he's not putting up multiples, so he doesn't need precise timing (yet).
>
> I suspect none of these are hundreds or thousands of people, but they all have some need to understand time and frequency to a "more than you get with a TinySA or oscilloscope" kind of performance.
>
>
>
> On Fri, 11 Apr 2025 12:46:12 +0200, Erik Kaashoek via time-nuts <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
EM
Ed Marciniak
Sat, Apr 12, 2025 2:05 AM
In order to perform close in phase noise measurements that may take 20+ minutes. I need excellent frequency stability, and in particular, must not have phase jumps.
For amateur radio microwave operation, I also need precise frequency references.
From: Jim Lux via time-nuts time-nuts@lists.febo.com
Sent: Friday, April 11, 2025 12:26:40 PM
To: time-nuts@lists.febo.com time-nuts@lists.febo.com
Cc: Jim Lux jim@luxfamily.com
Subject: [time-nuts] Re: As there a hobby application of precise time or frequency measurement except for being a time nut?
A lot depends on what you consider "precise" of course...
Radio astronomy - more and more people (yeah, probably < 1/2 dozen, but..) are setting up interferometers and precise time knowledge is important.
Radio amateurs on microwave frequencies with narrow band signals need good frequency control (1ppm at 10 GHz is wildly insufficient - you'd like to be within 10 Hz - 1E-9)
There seems to be a bunch of people doing direction finding with a distributed system (perhaps collaborative drone flight) - it's unclear what their requirements are.
There is a hobby radar community with bistatic radars - both at low frequencies (chirp sounders) and at microwave frequencies. The performance of the radar depends on both long term stability (for SAR) and closein (phase noise).
I know a guy with a LTE base station he built in his house - granted he's not putting up multiples, so he doesn't need precise timing (yet).
I suspect none of these are hundreds or thousands of people, but they all have some need to understand time and frequency to a "more than you get with a TinySA or oscilloscope" kind of performance.
On Fri, 11 Apr 2025 12:46:12 +0200, Erik Kaashoek via time-nuts 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
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In order to perform close in phase noise measurements that may take 20+ minutes. I need excellent frequency stability, and in particular, must not have phase jumps.
For amateur radio microwave operation, I also need precise frequency references.
________________________________
From: Jim Lux via time-nuts <time-nuts@lists.febo.com>
Sent: Friday, April 11, 2025 12:26:40 PM
To: time-nuts@lists.febo.com <time-nuts@lists.febo.com>
Cc: Jim Lux <jim@luxfamily.com>
Subject: [time-nuts] Re: As there a hobby application of precise time or frequency measurement except for being a time nut?
A lot depends on what you consider "precise" of course...
Radio astronomy - more and more people (yeah, probably < 1/2 dozen, but..) are setting up interferometers and precise time knowledge is important.
Radio amateurs on microwave frequencies with narrow band signals need good frequency control (1ppm at 10 GHz is wildly insufficient - you'd like to be within 10 Hz - 1E-9)
There seems to be a bunch of people doing direction finding with a distributed system (perhaps collaborative drone flight) - it's unclear what their requirements are.
There is a hobby radar community with bistatic radars - both at low frequencies (chirp sounders) and at microwave frequencies. The performance of the radar depends on both long term stability (for SAR) and closein (phase noise).
I know a guy with a LTE base station he built in his house - granted he's not putting up multiples, so he doesn't need precise timing (yet).
I suspect none of these are hundreds or thousands of people, but they all have some need to understand time and frequency to a "more than you get with a TinySA or oscilloscope" kind of performance.
On Fri, 11 Apr 2025 12:46:12 +0200, Erik Kaashoek via time-nuts <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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M
Mike
Sat, Apr 12, 2025 12:24 PM
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.
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.
> _______________________________________________
JT
Joe Theobald
Sat, Apr 12, 2025 4:15 PM
My first exposure to precision timekeeping was by an amateur astronomer who was observing occultations of stars and required a precision clock. This was back in the mid-70’s. He built a WWV receiver and worked with NIST to get estimates of propagation delays to get his best time estimate.
Joe Theobald
jltheobald@cox.net
On Apr 12, 2025, at 5:24 AM, Mike via time-nuts time-nuts@lists.febo.com wrote:
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.
My first exposure to precision timekeeping was by an amateur astronomer who was observing occultations of stars and required a precision clock. This was back in the mid-70’s. He built a WWV receiver and worked with NIST to get estimates of propagation delays to get his best time estimate.
Joe Theobald
jltheobald@cox.net
> On Apr 12, 2025, at 5:24 AM, Mike via time-nuts <time-nuts@lists.febo.com> wrote:
>
> 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.
>> _______________________________________________
> _______________________________________________
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