Introduction In a recent post I was considering a hypothetical 2m amateur radio repeater and studying its VHF coverage with a Yagi antenna (Ref.1). In the process I read an article describing the difference in results of using the Longley-Rice & ITWOM propagation models (Ref2). The researchers used the Radio Mobile program developed by Roger… Continue reading VHF Marine Propagation with Radio Mobile
Category: Navigation
Navigation: Celestial, Sextant, Equipment
Splat! – Antenna Patterns
Introduction Splat! (Ref.1) is a very versatile propagation prediction program that I discussed in several previous posts. In my first post, I looked at installation on Windows and Linux, how to obtain the digital elevation data files, create .qth & .lrp files, and run a simple point to point analysis (Ref.2). In the second and… Continue reading Splat! – Antenna Patterns
Marine GMDSS/NAVTEX MF Decoder
Introduction In previous posts I looked at various aspects of decoding BFSK GMDSS/DSC using GNURadio, SDRangel, Multipsk and Scicos. In the last post I used a BPF Non-Coherent GNURadio FSK decoder to decode random data (Ref.1). In this post I will use the same decoder to examine a short GMDSS/NAVTEX BFSK message (Ref.2). BFSK BPF… Continue reading Marine GMDSS/NAVTEX MF Decoder
OpenPlotter3 – AIS & GPS on RPi3B
Introduction Recently I revisited OpenPlotter after a two year interval to see what had changed in the latest version 3 (Ref.1/3). I tested the Starter and Headless images and setup AIS & GPS on RPi4/OpenCPN. In 2021 I had looked at various aspects of version 2 (Ref.4/5). In this post I will look at OpenPlotter3… Continue reading OpenPlotter3 – AIS & GPS on RPi3B
CelNav Victoria Day Lunar Distance
Introduction I just finished a very interesting book about Capt. Cook’s third and final voyage – “The Wide Wide Sea” by Hampton Sides (Ref.1). So I thought it would only be appropriate on Victoria Day to take a lunar measurement as Capt. Cook might have taken. Apparently he also took a K1 chronometer made by… Continue reading CelNav Victoria Day Lunar Distance