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Introduction In my last post I looked at using the RTL-SDR for receiving Marine GMDSS/DSC signals on HF/VHF (Ref.1). Reception was done using Multipsk on Windows 10. In this post I examine using the RTL-SDR as a stand alone Marine VHF DSC receiver operating on the RaspberryPi4B. The RaspberryPi4B is configured for remote operation off… Continue reading RTL-SDR for Marine GMDSS/DSC on RaspberryPi4

Introduction Recently I received an interesting question from Scott in Vancouver about Marine Channel 70 and DSC Digital Selective Calling. DSC is a part of the GMDSS Global Maritime Distress and Safety System (Ref.1/2). It can be used by ships on the MF/HF bands or in the VHF band. The ship MMSI identifier can be… Continue reading RTL-SDR for Marine GMDSS/DSC on MULTIPSK

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

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