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Updated NOAA (markdown)

Brumi-2021
2025-05-11 15:33:40 +02:00
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NOAA.md

@@ -4,7 +4,10 @@ Currently, they are using those frequencies, (but in future it may change, bette
![image](https://github.com/user-attachments/assets/85e9e32f-7c69-44a6-aaeb-5695161beeca)
NOAA Polar Operational Environmental Satellites (POES) have an orbital period of approximately 102 minutes, approximately 520 miles (800 kms) above Earth, meaning they circle the Earth in about that time.The Earth's rotation allows the satellite to see a different view with each orbit, and each satellite provides two complete views of weather around the world each day. This allows them to complete about 14 orbits per day, passing over the same location twice daily, once during daylight and once at night.
NOAA Polar Operational Environmental Satellites (POES) have an orbital period of approximately 102 minutes, approximately 520 miles (800 kms) above Earth, meaning they circle the Earth in about that time.The Earth's rotation allows the satellite to see a different view with each orbit, and each satellite provides two complete views of weather around the world each day. This allows them to complete about 14 orbits per day, passing over the same location twice daily, once during daylight and once at night.Example of the 14 orbits , in 24h (Image from NOAA):
![image](https://github.com/user-attachments/assets/cf50aacf-6e41-414e-8a8b-8ed57ed9bf7d)
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.
@@ -18,8 +21,10 @@ It has a resolución of 4 Kms/pixel.
The maximum pass duration for NOAA satellites, when receiving signals from them using ground equipment, can be around 10 to 15 minutes. This duration refers to the time the satellite is visible and within signal range at a given location, from its initial rise above the horizon to its descent below the horizon on the other side. (If you have a pass just above of your (zenith = visual satellite max. elevation = 90º) , you can record the max. long pass, till around 1800 lines with max 15 min time aprox)
![image](https://github.com/user-attachments/assets/97116ed9-1b42-4773-96b1-9520216b60fc)
![image](https://github.com/user-attachments/assets/db5a686b-9e3f-4d90-8c93-f88acb7b5d13)
![image](https://github.com/user-attachments/assets/1ec86a40-ed3b-4170-84de-74767ebc552e)
![image](https://github.com/user-attachments/assets/97116ed9-1b42-4773-96b1-9520216b60fc)
![image](https://github.com/user-attachments/assets/bc7d2365-924f-49b3-a69c-73f8ab248697)
APT signal format : 120 lines / minute , sending two pictures at the same time (visible / infrared )