Introduction The GPS Global Positioning System is ubiquitous these days and can be even found equipped on all new smart phones. GPS information can easily be displayed on OpenCPN charts. GPS Global Positioning System The GPS system started as Navstar in the 1970s and became fully operational with at least 24 satellites continually orbiting the… Continue reading GPS on OpenCPN
Author: Jeremy Clark
RTL-SDR for VHF Air & Marine Bands
Introduction The RTL-SDR receiver is a simple but very useful device. It can receive signals from 25MHz to about 1700MHz. It can be used to scan the aircraft VHF AM voice band from 118 to 137MHz and then the Marine VHF FM band from 156 to 164MHz. VHF Air AM Voice Frequency Band The VHF… Continue reading RTL-SDR for VHF Air & Marine Bands
Splat! – Marine VHF Propagation
Introduction In a previous post, I discussed how to use the Friis equation to determine the free space loss and receive level between a transmitter and receiver (Ref.1). Let’s consider an example that I saw in a recent sailing forum. The discussion was around the range of a typical marine VHF transmitter using a quality… Continue reading Splat! – Marine VHF Propagation
RTL-SDR for EPIRB
Introduction EPIRB or Emergency Position Indicating Radio Beacon Station is an emergency transmitting device that blue water sailors or explorers can use in case of distress. They have proven their worth over the years and are absolutely essential for anyone wanting to wander off the grid (Ref.1). At least 2000 people have been saved every… Continue reading RTL-SDR for EPIRB
HF SSB vs. Digital Voice
Introduction In a recent YouTube video I saw a demonstration of a commercial HF radio communicating over a distance of 90Km using NVIS and digital voice. Using SSB the received signal was barely above noise level, and hardly decipherable. However, when the digital voice modem was switched on, the signal was very clear. I decided… Continue reading HF SSB vs. Digital Voice