Introduction The standard RTL-SDR receives from 25 – 1725MHz, which does not include the LF band from 30-300KHz, the MF band from 300KHz – 3MHz and the HF band from 3 – 30MHz. However with the use of an up-converter, these bands can be received (100KHz – 65MHz). Fig.1 shows the 1st version of the… Continue reading RTL-SDR for HF 0-30MHz
Celestial Navigation Basics – Aim Off
The sun is shining, it’s early morning and I’m on my deck, Colombian coffee in hand, reading a fantastic book “China Clipper: The Age of the Great Flying Boats” by Robert Gandt (Ref.1). It is the amazing story of the American airline Pan Am crossing the Pacific in 1935. In order to fly safely with… Continue reading Celestial Navigation Basics – Aim Off
RTL-SDR for Marine HF Weather Fax
Introduction Up to date weather information is critical for sailors and can make the difference between a safe or a hazardous passage. Marine HF Weather Fax has been working reliably for many years and is an independent source of valuable information. NOAA’s Marine Weather Fax page (Ref.1) has all the information you need to use… Continue reading RTL-SDR for Marine HF Weather Fax
Celestial Navigation Basics – Fix
In this post we will look at how to generate a fix from observations of two Celestial Bodies. In previous posts we looked at Hc (Ref.9), Ho (Ref.8), Ha (Ref.7) and Hs (Ref.6). Now we are in a position to use Ho & Hc from two measurements to get our fix. The Marcq St. Hilaire… Continue reading Celestial Navigation Basics – Fix
RTL-SDR for AIS
Introduction AIS Automatic Identification System for Ships is a traffic system that uses VHF transponders on vessels to periodically send out location information. It was developed by Swedish inventor Hakan Lans and is similar in concept to the ADS-B transponder system used on aircraft for position reporting. AIS uses two VHF marine channels 87B (161.975 MHz)… Continue reading RTL-SDR for AIS