RTL-SDR Blog Wideband LNA
The Wideband LNA is based on the Qorvo SPF5189Z LNA chip (datasheet pdf) which has the following declared specs:
- Frequency range of 50 MHz to 4000 MHz
- Noise figure = 0.6dB @ 900 MHz
- OIP3 = 39.5 dBm @ 900 MHz
- P1 Saturation = 22.7 dBm @ 1960 MHz
- Gain = 18.7 dB @ 900 MHz
Compared to most of the other SPF5189Z LNAs found on eBay, our wideband LNA comes standard with a full conductive metal case, includes ESD protection on the antenna input, and is by default powered via 3 – 5V bias tee power. Our RTL-SDR Blog V3 dongles have a 4.5V bias tee built in, so they can be used to power this LNA. Direct power can be enabled simply by changing a jumper position, and removing the metal case.
This is a general purpose wideband LNA. It is useful for reducing the noise figure and thus increasing SNR, and for overcoming coax loss on all supported frequencies between 50 – 4000 MHz. However, because it is wideband you may need additional filtering if you have strong overloading signals in your area. If you’re mostly interested in improving ADS-B reception, then we instead recommend our Triple Filtered ADS-B LNA which is also available at our store. The specs of the SPF5189Z are similar to that of PGA-103+ or PSA4-5043+ based LNAs. In the image slider below we compare the gain with the LNA4ALL which is a PSA4-5043+ based LNA.