VOACAP (Voice of America Coverage Analysis Program) is free professional high-frequency (HF) propagation prediction software from NTIA/ITS, originally developed for Voice of America (VOA). In this video we will study the propagation between the time signal station CHU located in Ottawa Canada with a receiver located at VE3PKC in Toronto Canada. The actual received signal… Continue reading VOACAP – CHU to VE3PKC
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
Dirac Delta Function – δ(t)
Introduction The unit impulse or Dirac Delta function δ(t) is an essential building block of modern telecommunications, similar in importance to the FFT that was examined in the previous post. The function came about as a result of research done by the British Physicist Paul Dirac on the modelling of a point charge (Ref.1). It… Continue reading Dirac Delta Function – δ(t)
FFT – A Telecommunications Revolution
The FFT or Fast Fourier Transform was described by Cooley & Tukey in their 1965 paper “An Algorithm For The Machine Calculation of Complex Fourier Series” (Ref.1). The method has earlier roots in the works of Carl Gauss and others (Ref.2). The purpose of the FFT is to reduce the calculation complexity of the DFT… Continue reading FFT – A Telecommunications Revolution
GNU Radio ATSC_8VSB Transmitter Simulation
In the previous post, I discussed using Splat! to predict the receive level of an RF signal. In particular I considered CBLFT UHF CH25 as received from the CN Tower as shown above in Figure 1. In order to study ATSC_8VSB which is the DTV standard used in North America, GNU Radio can be used… Continue reading GNU Radio ATSC_8VSB Transmitter Simulation