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reynico / raspberry-noaa

Fully automated ISS SSTV, NOAA and Meteor satellite image downloader using Raspberry PI
https://github.com/reynico/raspberry-noaa
GNU General Public License v3.0
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Bad image quality / Enable AGC #28

Closed Crosswalkersam closed 4 years ago

Crosswalkersam commented 4 years ago

Hi, I am using the Raspberry Pi 4 2Gb with a Nooelec neSDR SMARTEE and a Nooelec NOAA Sawbird filter. I am struggeling to get a good image. With the Pi 2B+ and the "normal" neSDR SMART the images were great. I guess it has to do something with the gain. I tried everything from 10dBm to 50dBm in the receive.sh file. Do you know why that is? Maybe Automatic gain control would help, but how do I enable it?

NOAA1820200726-121056-ZA

Many thanks, Sam

reynico commented 4 years ago

Hi Sam, just remove the -g param from rtl_fm, that enables the AGC. I'm using a FM trap filter and a RTL-SDR v3 receiver, been trying for a while with different amplifiers but had no luck at all, best images were captured just with the receiver and the filter.

Crosswalkersam commented 4 years ago

Thanks! With AGC enabled and without LNA it works fine. But I have no idea why it refuses to work with the LNA. I tried different gain settings,supplied the LNA with USB or Bias-T but none of that did the trick. Even different antenna types(I tried QFH,DCA and Yagi).