NF1J NF1J Ham Radio November Foxtrot One Juliet

SDR / Receive Projects

Build a receive lab for shortwave, satellites, ADS-B, and local signals.

RTL-SDR starter station, upconverter notes, broadcast filters, NOAA satellite antennas, ADS-B antennas, receive long wires, and active loops.

View SDR projectsOpen SDR helper
RX Receive onlyNOAA 137 MHzADS-B 1090 MHz
Receive Lab Rule

Filters and antennas matter.

An inexpensive SDR can perform very well when strong local signals are filtered and the antenna is matched to the band.

  • Use a good USB cable and keep noise away.
  • Add filters if FM broadcast or AM broadcast overload appears.
  • Use receive-only protection when sharing station antennas.

SDR Helper

Quarter-wave receive element calculator

Quick dimensions for receive antennas such as NOAA V-dipoles and ADS-B ground planes.

DIY Project Library

Receive and SDR builds

Most of these are receive-only projects. Do not transmit into SDR inputs without proper protection and switching.

RTL-SDRRECEIVE PROJECT

Starter

RTL-SDR starter station

A clean starter layout for USB SDR, coax, adapters, filters, and basic receive antennas.

Build focusSDR dongle, USB extension, adapters, small antenna, optional filters
  1. Place the SDR away from computer noise with a USB extension.
  2. Start with a known local FM/weather signal.
  3. Add filters only after identifying overload.

Receive-only note: protect SDR inputs from transmitters, static, and strong local signals.

HF UPCONVERTERRECEIVE PROJECT

HF receive

SDR upconverter explanation

A simple concept guide for moving HF signals into the tuning range of VHF-only SDR receivers.

Build focusUpconverter module, HF antenna, USB power, coax jumpers
  1. Feed the HF antenna into the upconverter.
  2. Set SDR software frequency offset correctly.
  3. Use bandpass filtering for noisy locations.

Receive-only note: protect SDR inputs from transmitters, static, and strong local signals.

FM TRAPRECEIVE PROJECT

Overload fix

Broadcast FM trap

A filter project to reduce strong 88-108 MHz signals that overload wideband SDRs.

Build focusFM notch filter or LC filter module, shielded box
  1. Install between antenna and SDR.
  2. Compare waterfall before and after.
  3. Bypass when listening to FM broadcast.

Receive-only note: protect SDR inputs from transmitters, static, and strong local signals.

AM FILTERRECEIVE PROJECT

HF cleanup

AM broadcast band filter

A high-pass or notch filter to reduce strong local AM broadcast stations on HF receive.

Build focusFilter module, shielded enclosure, coax connectors
  1. Place close to the SDR input.
  2. Ground the enclosure if needed.
  3. Check that desired HF bands remain strong.

Receive-only note: protect SDR inputs from transmitters, static, and strong local signals.

NOAA V-DIPOLERECEIVE PROJECT

Satellites

NOAA weather satellite receive antenna

A simple V-dipole or turnstile-style receive antenna for 137 MHz weather satellite images.

Build focusTwo elements, mast, coax, angle bracket
  1. Cut quarter-wave elements for 137 MHz.
  2. Set the V shape and point broadside to satellite passes.
  3. Use SDR software to decode APT images.

Receive-only note: protect SDR inputs from transmitters, static, and strong local signals.

ADS-B GPRECEIVE PROJECT

Aircraft RX

ADS-B 1090 MHz antenna

A small ground-plane antenna for aircraft ADS-B reception.

Build focus1090 MHz vertical element, radials, SMA/N connector
  1. Cut the vertical and radials near quarter-wave.
  2. Mount high with clear sky view.
  3. Use low-loss coax if the run is long.

Receive-only note: protect SDR inputs from transmitters, static, and strong local signals.

RX LONG WIRERECEIVE PROJECT

Shortwave

Receive-only long wire

A simple receive antenna for shortwave listening with static bleed and isolation notes.

Build focusInsulated wire, 9:1 receive UNUN optional, ground, coax
  1. Run wire away from house noise.
  2. Add a receive-only matching transformer if needed.
  3. Disconnect during storms.

Receive-only note: protect SDR inputs from transmitters, static, and strong local signals.

ACTIVE LOOPRECEIVE PROJECT

Low noise

Active receive loop

A compact receive loop concept for noisy lots and directional nulling.

Build focusLoop wire/tubing, active amplifier module, bias tee
  1. Build the loop mechanically stable.
  2. Power the active amp through a bias tee if supported.
  3. Rotate to null local noise.

Receive-only note: protect SDR inputs from transmitters, static, and strong local signals.