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Updated NOAA (markdown)

Brumi-2021
2025-05-11 23:55:24 +02:00
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NOAA.md

@@ -41,7 +41,7 @@ APT signal format : 120 lines / minute , sending two pictures at the same time
# Usage
Hackrf, like the rest of SDR receivers, have not enough sensitivity to receive directly those NOAA APT maps with the stock rod antenna. To receive those signals , the best would be to use an omnidirectional QFH 137 Mhz antenna band ,or a proper 137 Mhz dipole (but you will need to manually point the antenna to the satellite ) + bandpass amplifier (specially useful if you have noisy strong adjacent channels, it will help to improve the reception).
Hackrf, like the rest of SDR receivers, have not enough sensitivity to receive directly those NOAA APT maps with the stock rod antenna. To receive those signals , the best would be to use an omnidirectional QFH 137 Mhz antenna band ,or a proper 137 Mhz dipole + bandpass amplifier (if you have noisy strong adjacent channels, it will help to improve the reception).
The most simple antenna you can use is a [V-dipole antenna](https://lna4all.blogspot.com/2017/02/diy-137-mhz-wx-sat-v-dipole-antenna.html), consists of two wires or rods of 52cm, spread apart by 120 degrees. Instead of using a protactor you can use trigonometry, the distance between the tips of each rod should be around 90cm.