Introduction Communications for blue water sailors is extremely important. Reliable satellite communications for voice, email and GRIB weather files has become common place. This service is expensive, however, depending on usage. HF communications for voice & email is another alternative. This has the conventional drawbacks of propagation reliability, connectivity and bandwidth. There are several commercial… Continue reading HF Messaging with OFDM_a
RTL-SDR for HF WWV Propagation
Introduction Recently I was in Costa Rica (Ref.1) and I used WWV to set my watch for UTC time to accurately read my sextant. We tend to take time for granted now with the Internet & GPS, but time stations like WWV still provide an essential service. WWV (Ref.2) can also be used to study… Continue reading RTL-SDR for HF WWV Propagation
RTL-SDR for AIS & ADS-B on Local Map+
Introduction In previous posts I looked at receiving both AIS & ADS-B on SDRangel (Ref.1) as well as displaying them on OpenCPN using a combination of aisdeco2 & MULTIPSK (Ref.2). The immediate application for this is for an off shore oil/exploration rig, where knowledge of local ships is important (AIS), as well as incoming/outgoing helicopters… Continue reading RTL-SDR for AIS & ADS-B on Local Map+
RTL-SDR for UTC Time in the Tropical Rainforest
Introduction In order to take an accurate sextant sight, we need to have precise time, ideally within 1 second. The Earth revolves at 360deg/24hours = 15deg/1hour = 15min_arc/min_time = 1min_arc = 4secs_time. A shortwave receiver can be used to get this time using international time stations. WWV UTC Shortwave Time Station In Toronto, time stations… Continue reading RTL-SDR for UTC Time in the Tropical Rainforest
SDR for QO-100 Satellite Reception – Planning
Introduction Recently I read an interesting post on an sdr newsgroup discussing the Es’hail 2 satellite also known as QO-100 (Qatar Oscar 100). This is a geostationary satellite designed for DBS or direct broadcast television transmission to North Africa and the Middle East (Ref.1). The satellite has Ku (12-18GHz) and Ka (27-40GHz) band transponders for… Continue reading SDR for QO-100 Satellite Reception – Planning