3 ms·

If you're into receiving low frequency time signals, you can receive them directly with nothing more than a piece of wire connected to the mic input of a modern

by zh3 2y ago

If you're into receiving low frequency time signals, you can receive them directly with nothing more than a piece of wire connected to the mic input of a modern sound card (via a capacitor). Sample at 192kHz and downsample in software (simplest: mix with a similiar frequency sine and listen to the result, say 59kHz for WWVB or MSF).

elzbardico 2y ago
The 2024 version of the crystal radio. :-D
accra4rx 2y ago
are there any good circuits for radio transmitter (circuit for low freq esp 60KHz)
- zh3 2y ago
  It's super-easy for very short range, super-difficult for long range. Reason is the wavelength is so long (speed of length/60KHz = 5Kms) that you need a massive aerial for lange range, however for short range you can feed the MW or LW coil of an AM radio to spoof a time signal (ideally make it resonant by adding the right amount of capacitance, look up "tank circuit"). Watch out if you add amplification though, due to the lnog wavelength and the high inductances involved (if you get that far) it is possible to end up with dangerous voltages at the aerial feed. A sound card with a true 192Khz sample rate should be enough to fool a radio clock next to the transmitter coil - though be aware a lot of sound cards may not actually output the 60kHz carrier frequency required.
  - accra4rx 2y ago
    Thank you sir, I am going to get a sound card with 192Khz and try that out
aidenn0 2y ago
Really just a piece of wire? I would have thought that there would be too much noise to pick up WWVB without a somewhat more selective antenna (loopstick maybe?)
- zh3 2y ago
  Yes, depends of course on distance, aerial layout and on the decoding technique. Anything over a few hundred miles needs amplification/attention to aerial resonance etc, simply mixing (multiplying) the received signal wth a sine wave close to the same frequency results in a quite audible signal (strength varies throughout the day though). Used to be easy to pick up Loran signals in the same way (esp. with untuned aerials) but they're all turned off now.
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by zh3 2y ago

elzbardico 2y ago

The 2024 version of the crystal radio. :-D

accra4rx 2y ago

are there any good circuits for radio transmitter (circuit for low freq esp 60KHz)

zh3 2y ago
It's super-easy for very short range, super-difficult for long range. Reason is the wavelength is so long (speed of length/60KHz = 5Kms) that you need a massive aerial for lange range, however for short range you can feed the MW or LW coil of an AM radio to spoof a time signal (ideally make it resonant by adding the right amount of capacitance, look up "tank circuit"). Watch out if you add amplification though, due to the lnog wavelength and the high inductances involved (if you get that far) it is possible to end up with dangerous voltages at the aerial feed. A sound card with a true 192Khz sample rate should be enough to fool a radio clock next to the transmitter coil - though be aware a lot of sound cards may not actually output the 60kHz carrier frequency required.
- accra4rx 2y ago
  Thank you sir, I am going to get a sound card with 192Khz and try that out

aidenn0 2y ago

Really just a piece of wire? I would have thought that there would be too much noise to pick up WWVB without a somewhat more selective antenna (loopstick maybe?)

zh3 2y ago
Yes, depends of course on distance, aerial layout and on the decoding technique. Anything over a few hundred miles needs amplification/attention to aerial resonance etc, simply mixing (multiplying) the received signal wth a sine wave close to the same frequency results in a quite audible signal (strength varies throughout the day though). Used to be easy to pick up Loran signals in the same way (esp. with untuned aerials) but they're all turned off now.

deleted 2y ago

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