If a sailor is going the manage marine risks then understanding the weather is an important consideration. Modern satellite imagery and computers have enabled meteorologists to be quite accurate with weather forecasts up to 5 days in advance. This means for short voyages a sailor could obtain an accurate understanding of the likely weather conditions during the cruise. If the vessel is going to be out of range of line of sight (eg, mobile phone, VHF radio) weather information there appears to be two main options.
The first is to obtain weather updates via a satellite receiver and the second by HF radio. The latter is the cheaper option as the broadcast data is free whilst the former requires an ongoing subscription.
One of the main means of receiving weather forecasts by HF radio is to use the WeatherFax service. The origins of Weatherfax are based on RadioFax which was invented in the 1920’s. Essentially it is a facsimile image broadcast on a High Frequency wavelength. Almost everyone has seen a fascimile image which has been scanned by one machine and sent over the telephone line to another which prints it out.
The Weatherfax system has the meteorologists scan their weather image and then broadcast it over HF radio. The receiving radio sends the analogue data to a computer where it can be displayed as an image on a computer screen.
To receiver Weatherfax data a vessel requires a suitable HF radio, asound card to convert the received audio data to digital and a computer to process the digital data into a weather map. That all sounds easy but it somewhat more difficult than receiving the data by satellite. Nevertheless, if you already have a suitable radio it’s the cheaper option.
In 1989 I was heading to Iran and during an overnight stop in Singapore I purchased a Sony SSB HF Radio. It wasn’t cheap however I had already realised I’d need some means of keeping myself independently informed about world events during the following 12 months.
I’d sit down at night and string out the radio aerial before listening to various national radio services such as the BBC, VOA (Voice of America), the Russian overseas service, the Australian Broadcasting Service and on one night I actually received the New Zealand Broadcasting Service. The latter was quite a surprise as the transmitter wasn’t very powerful and the antenna was directed towards the South Pacific. Yes… I don’t like to throw things away which might be useful one day. I still have the radio!
The radio has an audio output jack which could be connected to a USB sound card that was plugged into a computer. Power is 6V DC either via AA batteries or 240V. It wouldn’t be very hard to convert the radio to operate off a boat 12V system through a cheap 12V – 6V converter. This eliminates the requirements for batteries or 240V. A quick internet search suggests a USB sound card can be purchased for $2-3. I could assemble a Weatherfax system for about $10.
The last question is whether the eldest grandson needs or wants such a system?
2 comments :
We used a similar radio to receive WeatherFax on our yacht over 20 years ago. I am not sure Australia is broadcasting weather faxes any more, there have been a couple of surveys and threats to stop the service. Last trip to SE Asia 2015-16 we used the Predictwind service, there is free and paid, which we received over HF, but most people use a sat phone to receive the forecasts. The HF conditions have been so poor the last few years, we had some difficulty receiving them, and only used the HF when there was no mobile phone service to receive Predictwind from the landbased internet.
Hi Catherine,
The BOM still broadcasts WeatherFax. I'm, aware of Predictwind but wasn't aware you could receive it using HF. My understanding was you required satellite comms. Whether I proceed with this sub-project will depend on our grandson's cruising plans. If he is staying to coastal cruising then I don't see the need!
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