SatNOGS is focused on TX operations for Low Earth Orbit (LEO) satellites. Most satellites in those orbits transmit signals in relatively low power (compared to GSO satellites). 100mW to 2W is a typical range for LEO. Given that power output and our RX assembly (yagi + dvb dongle for reception) a Low Noise Amplifier can really improve our RX capabilities.
We decided that LNA would be an integral part of our RX assembly early on, but we could not easily find something that would meet our requirements (bands, noise figure, cost, size etc). After browsing and researching a lot of different options out there, we stumbled upon LNA4ALL.
LNA4ALL [1] is a great project by 9A4QV. The amplifier is built around Mini-Circuits PSA4-5043+ E-PHEMT Ultra Low noise MMIC amplifier operating from 50 MHz to 4 GHz. Small SOT-343 package combine low noise and high IP3 performance with internal match to 50 ohms. With 20 Euros as a pricetag, this was the LNA we were looking for.
We are using our 5V output from the regulator we have inside SatNOGS as VCC for the LNA (required a tiny bit of modification) and the LNA is connected in line between our RX dongle and the antenna (using SMA connectors)
Initial tests are showing great improvement in our reception (tested against a variety of bands, encoding and satellites) making this LNA an irreplaceable part of our project.
Proper shielding and housing should be in place, so we designed [2] and 3d printed quickly a housing for this LNA. Some grounded aluminum tape makes up for a shield.
More tests will follow, and we are designing new antennas and evaluating their matching.
[1] http://lna4all.blogspot.com/
[2] https://github.com/satnogs/satnogs-hardware/tree/master/Lna
