Introduction In previous posts I examined the possible use of OFDM for HF messaging (Ref.1/2/3) and for voice (Ref.4). I introduced several channel models using Scicos: an 8 channel discrete model and a 64 channel model using IFFT/FFT. In this post I will focus on using FEC Forward Error Correction to improve the transmission performance.… Continue reading FEC Forward Error Correction on GNU Radio
HF Messaging with OFDM_c
Introduction In previous posts I examined the possible use of OFDM for HF messaging (Ref.1/2) and for voice (Ref.3). I introduced several channel models using Scicos: an 8 channel discrete model and a 64 channel model using IFFT/FFT. In the last post I concentrated on the IFFT transmitter. In this post I will focus on… Continue reading HF Messaging with OFDM_c
HF Messaging with OFDM_b
Introduction In previous posts I examined the possible use of OFDM for HF messaging (Ref.1) and for voice (Ref.2). I introduced several channel models using Scicos. In this post I will expand my Scicos 8 channel model to a 64 channel model generated by IDFT. OFDM IFFT/FFT 64Ch Model In order to obtain the benefits… Continue reading HF Messaging with OFDM_b
Lunar Distance – DST to EST
Introduction Saturday November 5th was an ideal evening to measure a Lunar from my balcony. It was unseasonably warm at 20degC and I had just removed all the gear, as my balcony is going to be rebuilt for the third time in five years, so I might as well enjoy the last few jack hammer… Continue reading Lunar Distance – DST to EST
RTL-SDR for VHF Marine Scanner on SDR#
Introduction Recently I was approached for advice on frequency scanning. My first thought was a traditional approach of starting at the base frequency, stepping by the channel spacing and doing a power evaluation. If greater than a threshold, then hold and attempt a decode. Before building a prototype in GNU Radio, I thought I would… Continue reading RTL-SDR for VHF Marine Scanner on SDR#