Introduction In previous posts I have tested the various HF & VHF antennas that I have using the versatile NanoVNA (Ref.4/5/6). In the last post I decided to try pushing the NanoVNA beyond it’s spec of 1.5GHz to test my Inmarsat Patch antenna (Ref.1). In this post I will test the L band microwave dish… Continue reading L Band Dish Antenna Testing with NanoVNA
Si5351 Clock Generator Programming
Introduction Six years ago I designed a zero IF direct conversion receiver to be used with my HF Radio Ebook (Ref.1). For flexibility, I used an IQ VFO. At the time, the best choice for my VFO was the Si514. In order to get coswct & sinwct waveforms, I had to run the VFO at… Continue reading Si5351 Clock Generator Programming
Inmarsat Patch Antenna Testing with NanoVNA
Introduction In previous posts I looked at receiving Inmarsat satellite signals (Ref.1/2). I used an L band dish and patch antenna. I was wondering what the overall SWR of these antennas looked like, so I decided to test them with the NanoVNA. The NanoVNA that I purchased was spec’d to 1.5GHz, but I guessed that… Continue reading Inmarsat Patch Antenna Testing with NanoVNA
FEC Forward Error Correction on GNU Radio
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