Jeremy Clark – Page 9 – Telecommunications, Navigation & Electronics

NanoVNA for 433MHz/70cm LNA Testing

Introduction In the previous post I tested a 433MHz LNA with a PlutoSDR as a signal generator and determined it had a wideband response over 100MHz – 800MHz with a gain of approx. 23dB. In this post I will do the same measurement but this time with a NanoVNA. I am always looking for an… Continue reading NanoVNA for 433MHz/70cm LNA Testing

PlutoSDR for 433MHz/70cm LNA Testing on GNURadio

Introduction I want to do some experiments in the amateur radio 433MHz/70cm band. So I was looking for an LNA/BPF as I used in previous experiments. I found two units on line, one in a metal case and one on an open PCB. The PCB unit arrived first, so I tested it using white noise.… Continue reading PlutoSDR for 433MHz/70cm LNA Testing on GNURadio

Si5351 Clock Generator Spectrum on GNURadio

Introduction In previous posts I looked at programming the Si5351A clock generator for IQ quadrature and for simple single frequency output using Arduino (Ref.1/4). When used with amateur radio receivers and transmitters, we have to keep in mind that we are not dealing with a sinusoidal source but a square wave. From Fourier theory, a… Continue reading Si5351 Clock Generator Spectrum on GNURadio

OpenPlotter4 on RPi4 – AIS/GNSS/Sensors

Introduction In previous posts I looked at OpenPlotter2, then recently OpenPlotter3 (Ref.1/6). I looked at various aspects including GPS, AIS, WeFax, Navtex and Sensors. In this post I will look at OpenPlotter4 on RPi4 with AIS, GNSS and Sensors. Installation Figure 2 shows the OPV4 starter image which I downloaded from Ref.7. Then I used… Continue reading OpenPlotter4 on RPi4 – AIS/GNSS/Sensors

Magnetic Anomaly Detection

Introduction In a previous post I reviewed magnetic navigation and my personal experience using various compasses and magnetometers (Ref.1). In this post I will examine a different magnetometer the Melexis MLX90393. Recent aerial activity of anomalous vehicles suggests that having a method to measure magnetic fields is important. These craft cause all electrical activity to… Continue reading Magnetic Anomaly Detection