Tech5_VHFwav_Samples of Warnings VHF Ch16 or the armchair radio-sailor

Tech5_VHFwav

Samples of Warnings VHF Ch16 or the armchair radio-sailor


Samples of Warnings/Notice to Mariners. North Atlantic Coast of Portugal. Voice VHF, after short call "all ships, all ships" in Ch16 directing to Ch11.

Sample1 VHF16_11.wav link:

https://drive.google.com/file/d/1zRUGJ4iH_NQ5HffqdpAaTsTdms1g_l1A/view?usp=sharing

Sample2 VHF16_11.wav link:

https://drive.google.com/open?id=1BE4UrNyV6KKRxaH3CuFiR_8TAGhikHeO

Lots of RFI noise, operator not a native English speaker. Hard to understand, right? A common experience while sailing well known by seafarers.

From an armchair radio-sailor and with all the technical jargon, trying to find a portable and reliable solution to a real cruisers problem: the very low quality of User Interfaces(UI)/Human Machine Interfaces (HMI) for voice and data of commercial systems installed in leisure vessels.  Poor quality of audio, data truncated and/or presented in very small displays, limited (if any) possibility of recording voice messages and re-listen it or to read later the data messages in a really readable display. A concern with all the radio sources and fixed systems in leisure boats: L/M/HF frequencies, usually SSB, VHF, UHF (SafetyNet-Inmarsat and other satellite services).

A recommended good practice in big vessels (sorry, do not have the authoritative source at hand) is to have reception-only systems with clear sound alarms to  alert the officer on watch that a new message was received and recorded. The new  message could then be read, in a big and good enough display. Not sure if such good practice for big vessels addresses also VHF/SSB/Satellite verbal warnings. But this is/would be certainly a must for all types of ships.  Particularly, for our leisure vessels with limited radio equipment and with no 24h designated officer on watch at all.

In short,

In the real world of leisure sailing

(1) voice warnings and notice to mariners (regardless of the media, VHF/SSB/Satellite) are very often poorly heard and understood by the cruiser crew

(2) text messages are usually presented in very small, near to unreadable displays (see VHF-DSC “displays” even in the recent models high-end certified models)

Therefore,  having a way to automatically record and listen/read, as many times as necessary, both audio and text messages with a independent setup of the fixed in-board equipment, with a good audio/image output (i.e. at least our own portable computer …) should be a must. These issues were the primary motivation for my interest in Software Defined Radio with mid-range equipment as the SDRPlay models.

Setup

See previous messages on general setup of antennas and SDR hardware

Sampled recorded from a flat, 4^th floor. In a very busy city area.

Antenna in the inside face of a large window facing NW with a field of view from 20 to 210 degrees (magnetic), thus,  in a anticlockwise direction,  from NNE to SSW.

About 10 Km/5,4 NM in a straight line from the nearest broadcasting VHF radio marine authority.

A very hard setup for receiving marine VHF but:

-       not as a far experience from those I and most seafarers have when navigating near to shore of large European urban areas

-       a good test-bed to stress the SDR setup, i.e., if it works here it should work while really sailing

-       meteo forecasts of winds up to 40 NM/h, rough seas with waves of 5-6 meters and peeks of 14-15 meters, so much safer and cosy to stay at home.