Hmm... I thought I had local time turned off, but it would explain it, so I'll check again, ta.
Edit: It seems the hardware clock cannot be set to the adjusted system time (like it should), so appears to be an MX linux problem... but will be rebuilding from latest linux source after new year anyway, so hopefully should resolve the issue.
DCF77 Time Signal Generator with ESP32 (classic)
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Re: DCF77 Time Signal Generator with ESP32 (classic)
I thought it was the other way round. The hardware clock is set manually (and repeated after a few weeks/months) to the best possible time via the BIOS settings. LINUX uses this BIOS clock at startup to set the Unix time and adjusts its software time if an NTP server can be used.[Local Link Removed for Guests] wrote: [Local Link Removed for Guests]Mon Nov 11, 2024 4:37 pm Hmm... I thought I had local time turned off, but it would explain it, so I'll check again, ta.
Edit: It seems the hardware clock cannot be set to the adjusted system time (like it should), so appears to be an MX linux problem... but will be rebuilding from latest linux source after new year anyway, so hopefully should resolve the issue.
Could it help in your isolated network to use a second network card and synchronise via NTP?
EDIT: I asked perplexity.ai …
Question: How does local time setting work on Linux systems?
Answer:
On Linux systems, time management is governed by two main clocks: the Hardware Clock (RTC) and the System Clock. The Hardware Clock operates independently of the operating system, while the System Clock is part of the Linux kernel and runs continuously as long as the system is active.
Time Setting
1. Hardware Clock: This can be set to either local time or UTC. UTC is preferred because it does not require adjustments for daylight saving time.
2. System Clock: This is usually synchronized with the Hardware Clock. Commands like `hwclock --systohc` set the Hardware Clock to the current system time.
Changing Time Zone
• Use `timedatectl` to check and change the time zone. Example: `timedatectl set-timezone Europe/Berlin`.
• Alternatively, a symbolic link from `/usr/share/zoneinfo/<timezone>` to `/etc/localtime` can be created to manually set the time zone.
Synchronization
For precise time setting, `ntpdate` can be used to regularly synchronize the system time with a time server.
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Re: DCF77 Time Signal Generator with ESP32 (classic)
Thanks Peter. that explanation helped me sort out the problem.
It was actually a 3 step sequence that was needed... update system clock from ntc, update hardware clock from system time, apply time changes. Now I can remove the 8 minute offset from the Annex Time Server.
It was actually a 3 step sequence that was needed... update system clock from ntc, update hardware clock from system time, apply time changes. Now I can remove the 8 minute offset from the Annex Time Server.
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Re: DCF77 Time Signal Generator with ESP32 (classic)
I have made a few small changes that make it very easy to connect the DCF77 time signal generator to almost any type of DCF77 radio-controlled clock.
If space in the clock is limited, you could think about using an M5 ATOM lite in its cute case and pin25 as output.
A more elaborated description can be found at https://peterneufeld.wordpress.com/2024 ... generator/
EDIT: One of my test scenarios with a separate magnetic loop resonant circuit
If space in the clock is limited, you could think about using an M5 ATOM lite in its cute case and pin25 as output.
A more elaborated description can be found at https://peterneufeld.wordpress.com/2024 ... generator/
EDIT: One of my test scenarios with a separate magnetic loop resonant circuit
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Re: DCF77 Time Signal Generator with ESP32 (classic)
That last picture looks with the loop looks like it could suit my needs Peter, did you buy the loop antenna or make it yourself ?
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Re: DCF77 Time Signal Generator with ESP32 (classic)
DIY, Robin ![Local Link Removed for Guests] wrote: [Local Link Removed for Guests]Sat Nov 16, 2024 5:49 pm That last picture looks with the loop looks like it could suit my needs Peter, did you buy the loop antenna or make it yourself ?
This is an embroidery hoop which I cruelly kidnapped from my wife , with 6 turns of flat computer cable and 300nF in parallel. My NanoVNA says that it resonates at 75kHz.
This was a good way to test with different clocks.
If you manage to twist a few turns around the original ferrite rod - this is the most reliable wireless way.
EDIT: The frame has a diameter of 21cm, 6 turns, 300nF; connected via 100Ohm between pin25 and GND. When I saw the frequency response of a 2€ LM386 amplifier board today, I had a terrible idea, but only for a very short fleeting moment

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Re: DCF77 Time Signal Generator with ESP32 (classic)
Well, the fact that I had to ask proves that you made a good job of it.
Rather than convince my wife to take up embroidery, I've had a better idea... build the loop aerial actually inside the housing of my round wall-hanging clock. The small radio clock module in the middle is not accessible, but if surrounded by the loop aerial it should receive a good non-contact signal - and doesn't even need to look good, I could simply hot glue the wire loop inside the case.
Rather than convince my wife to take up embroidery, I've had a better idea... build the loop aerial actually inside the housing of my round wall-hanging clock. The small radio clock module in the middle is not accessible, but if surrounded by the loop aerial it should receive a good non-contact signal - and doesn't even need to look good, I could simply hot glue the wire loop inside the case.
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Re: DCF77 Time Signal Generator with ESP32 (classic)
Perhaps you have an old ferrite rod from an AM radio lying around? Take it with the original winding and position it as close as possible PARALLEL to the clock's rod antenna. That should do the job perfectly
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Re: DCF77 Time Signal Generator with ESP32 (classic)
Go on, you know you want to. I won't tell anyone. I'll be keeping an eye on my clocks though[Local Link Removed for Guests] wrote: [Local Link Removed for Guests]Sat Nov 16, 2024 6:02 pm .... When I saw the frequency response of a 2€ LM386 amplifier board today, I had a terrible idea, but only for a very short fleeting moment....
