Uputronics filtered preamp for improved 868MHz Reception for FLARM/LoRa/ISM!

This unit is a small filter and preamp designed to go between a software-defined radio receiver and an antenna. Using a SAW bandpass filter and a low noise amplifier (LNA), it stops out-of-band intermodulation while providing additional gain for increased sensitivity. The LNA is before the SAW filter. This particular model is tuned for use with 868MHz frequencies.

This is a cost-effective SAW-based unit which gives excellent performance gains, compatible with most USB SDR Dongles such as the RTL USB, Airspy, Fun Cube etc.

You can power them from either bias tee (this item is 100% compatible with the Airspy bias-tee) or a simple USB-C cable (not included).

Bias-tee voltage input is 5V. Note: Unlike previous models, component supply issues mean bias-tee input voltage is 5V max.

The LNA used is a MiniCircuits PSA4-5043+ which provides at least 16dB of gain @ 868MHz. To stop out-of-band intermodulation an 868MHz SAW bandpass filter, which has a 15MHz bandwidth, is also present. The insertion loss of this filter is approximately 2.3dB, which does increase the overall noise figure of the unit to 0.75dB.

High-quality SMA female connectors are fitted for antenna input and radio output, a RED power indicator is provided.

Important Notes

• This unit does not have a transmit bypass and is for reception work only – use this unit instead
• Transmitting via this unit won’t work and may damage it.
• NOT SUITABLE FOR HELIUM CRYPTOMINING (No TX Bypass) – use this unit instead

Resources

• Datasheet
• 3D-printable mounts (Thingiverse)
  • With lugs
  • Without lugs
• CE Certificate of Conformity
• UKCA Certificate of Conformity