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Updated NOAA (markdown)

Brumi-2021
2025-05-11 15:57:02 +02:00
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NOAA.md

@@ -10,7 +10,7 @@ NOAA Polar Operational Environmental Satellites (POES) have an orbital period of
The [APT signal](https://www.sigidwiki.com/wiki/Automatic_Picture_Transmission_%28APT%29#Frequencies) is modulated in a AM subarrier of 2400 Hz , and then all this audio map information is broadcasted in FM in the 137 MHz band .The satellite is broadcasting it with a radiated power of 5W aprox. at 800 kms, so we may need QFH 137 Mhz antenna band or proper dipole + bandpass amplifier.
The [APT signal](https://www.sigidwiki.com/wiki/Automatic_Picture_Transmission_%28APT%29#Frequencies) is a 256-level amplitude-modulated 2400 Hz subcarrier, which is then frequency modulated onto the 137 MHz-band RF carrier. The satellite is broadcasting it with an effective radiated power of approximately 5 watts (37 dBm) at 800 kms from the ground earth . These signals are frequency modulated (FM) and carry low-resolution weather imagery. To receive those signals , we may need omnidirectional QFH 137 Mhz antenna band or proper dipole + bandpass amplifier.
The analogue APT weather map transmission was invented in the 60's
![image](https://github.com/user-attachments/assets/433e3db3-e541-42e4-bd0f-57ed64aed841)