RTL-SDR for Marine Weather on HF SITOR

Introduction In previous posts, I looked at receiving weather information over NOAA (Ref.1), GOES (Ref.2) and HF WEFAX (Ref.3). Various weather agencies also transmit marine weather information over HF SITOR (Simplex Teletype over Radio). SITOR is an RTTY teletype system with advanced features of error detection, redundancy and re-transmission not included in the regular Baudot… Continue reading RTL-SDR for Marine Weather on HF SITOR

GOES16 Weather Satellite – Signal Capture with Dish Balcony Mount

Introduction Last year I managed to receive GOES16 images using a temporary pole mounted dish (Ref.1/6). This was in early September. Shortly after this our balconies were closed off for repairs and only recently opened. I decided to make a more permanent dish mount so that I could receive images for several hours without having… Continue reading GOES16 Weather Satellite – Signal Capture with Dish Balcony Mount

AM Modulation on GNU Radio

Introduction In AM modulation, the amplitude of the carrier wave is varied in accordance with the modulation wave. This can be described by the modulation equation: AM = Ac*[1+m*cos(wm*t)]*cos(wc*t)]Modulation Waveform = Am*cos(wm*t)Carrier Wave = Ac*cos(wc*t)m = modulation index = Am/Ac <=1 When m = 1 (100%), the amplitude of the mod waveform is equal to… Continue reading AM Modulation on GNU Radio

RTL-SDR for HF Beacons Propagation Prediction

Introduction In a previous post, I looked at how the RTL-SDR can be used to receive HF stations in the NCDX/IARU HF Beacon network (Ref.1). These stations transmit on a schedule and can be used for HF propagation analysis. Various programs can also be used for HF propagation prediction (Ref.2), such as VOACAP (Ref.3) and… Continue reading RTL-SDR for HF Beacons Propagation Prediction