Weather fax software for tablets?

[oldvarnish]

Just another thought - assuming you are out of range of coastal forecasts, there is far more to be learned from a fax chart (providing you have spent a little time learning to interpret them) than there is from isolated GRIB files. Would Frank agree?

 

[franksingleton]

OK. Thank you, Buck and Varnish. Mental aberration on my part. My iPad has only an output. However, a little research has come up with http://speechrecsolutions.com/iPad_audio.html. That might work, I suppose.

Re

Just another thought - assuming you are out of range of coastal forecasts, there is far more to be learned from a fax chart (providing you have spent a little time learning to interpret them) than there is from isolated GRIB files. Would Frank agree?

Anyone going to sea should have, at least, a nodding acquaintance with synoptic charts, essentially a form of meteorological shorthand. Some knowledge of what fronts are end the relationship between isobars and winds is basic fundamental meteorology.

However, GRIB files will give a better idea of wind force and direction. They will also show areas of rain and give some idea of intensity. The CAPE parameter is a useful indication of lightning risk. The input from GRIBs would help anybody to interpret synoptic charts. Perhaps the most valuable aspect of synoptic charts from the UK and some other Met services is that they contain some human input and interpretation of computer output.

 

[GHA]

Just another thought - assuming you are out of range of coastal forecasts, there is far more to be learned from a fax chart (providing you have spent a little time learning to interpret them) than there is from isolated GRIB files. Would Frank agree?

I would agree with that, "learn" as in learn how to interpret a synoptic chart all on your own. Being on th budget side of things, offshore gribs have always been on the small side and you really don't get a feel for the bigger picture, with synoptic you can watch a low developing off Greenland and follow it down over few days, gribs are great to have access to but I offshore with a choice of just one I'd go for synoptic every time. Also gribs seem to fall apart a bit in very light airs and don't show the position of the item.

On a similar note, back when Herb was about it never made sense to me to hand over the weather routing of your boat to a stranger (though highly recomended). Always seemed like throwing away a perfect opportunity to stand on your own feet doing real world forecasting, rather than be told turn right a bit.

 

[franksingleton]

I would agree with that, ........................

On a similar note, back when Herb was about it never made sense to me to hand over the weather routing of your boat to a stranger (though highly recomended). Always seemed like throwing away a perfect opportunity to stand on your own feet doing real world forecasting, rather than be told turn right a bit.

To put my views into perspective, my longest passage has been three days/ But I spent 10 years of my career producing forecast charts in the early days of computer weather models. I know several blue water sailors one being a close personal friend..

I always took the same view about Herb. He was only as good as the synoptic charts produced by people like me. That was confirmed by my blue water friends. They did not use him.

If you have HF/SSB and a modem, then you can get both charts and GRIBs, The best of both worlds. Without a modem, then you are back to what many sailors had pre-2000. For long distance sailing there is nothing greatly wrong with that.

Your first consideration is to leave harbour with a sufficient window of around three days to get away from land. After that, you take what comes. RTW racers apart, most yachts are too slow to be weather routed. Storms are too big and forecasts long enough ahead are simply not good enough and never will be.

The priority is to have enough warning of bad weather in order to prepare vessel and crew. Synoptic charts are good enough for that purpose. GRIbs provide a good add-on.

However, most sailors are coastal hopers with relatively few passages over 24-48 hours and rarely over 5 days. They will not be equipped to blue water standards. Prime considerations will be to know when it will be safe to make the next passage and when the must make a passage in order to avoid being in the wrong place at the wrong time.

Such decisions can clearly be made using synoptic charts which should, in any case, always be heeded. However, interpretation of charts is not easy. GRIBs certainly give me more confidence when making decisions on how long to stay somewhere and when it is necessary to move on.

Using GRIBs with care, you can often be thinking 5 or 6 days ahead. See http://weather.mailasail.com/w/uploads/Franks-Weather/bookcover.pdf and http://www.bloomsbury.com/uk/search?q=reeds+weather+handbook&Gid=1. Publication fate is 2 Jan 2014.

 

[GHA]

If you have HF/SSB and a modem, then you can get both charts and GRIBs, The best of both worlds.

This I have now hopefully the ham set will help pull in wfax images better than a little ssb reciever, not that it was a problem across the Atlantic. Gribs coming in then via expensive satphone.

A question about gribs - do they contain gust data? Thinking about this today, with a synoptic when you see a front coming through you know the wind will get up a bit then veer but also will be much more gusty, this doesn't seem to show up on the gribs.


And a question for the android geeks - how do you get bluetooth audio in? I've a bluetooth audio transmitter but the tablet won't pair with it, doesn't like the ad2b format or something - any ideas?

 

[ShinyShoe]

And a question for the android geeks - how do you get bluetooth audio in? I've a bluetooth audio transmitter but the tablet won't pair with it, doesn't like the ad2b format or something - any ideas?

Bluetooth... evil...
What is your tablet? Version of android and make of tablet?
What is the transmitter?
What pairing process are you currently following?

To pair my android 4.1.2 phone to a headset which I guess should be a simillar process for yourself I do the following:

On Android go to settings -> Bluetooth [enable] -> Scan

I'm then presented with a list of devices as follows:
My device
Paired devices
Unpaired devices

My preference is to do this with the device I want to pair to switched off. Then to switch the device on in pairing mode (for a headset you hold the button in for 5 seconds usually and then it flashes). Immediately hit scan again - new device should appear.

I then tap the new device
It will ask to confirm passkey. Depending on the devices the next steps will vary. Default pass key is usually 0000 but will vary and some devices will not ask for a pass key but if they both had screens may do something different.

Pairing may not be enough. You may then need to click the settings on the pairing to do something... e.g. enable sound through it.

 

[GHA]

To pair my android 4.1.2 phone to a headset which I guess should be a simillar process for yourself I do the following:

It's a Sony experia, getting sound *out* is easy, right now enjoying gotan project on jango over the boat speakers wirelessly.

It's getting audio *in* to the tablet via bluetooth that's causing the problem. No line in either so the only way to recieve wfaxes is via the inbuilt mic through the radio speaker.

 

[franksingleton]

This I have now hopefully the ham set will help pull in wfax images better than a little ssb reciever, not that it was a problem across the Atlantic. Gribs coming in then via expensive satphone.

A question about gribs - do they contain gust data? Thinking about this today, with a synoptic when you see a front coming through you know the wind will get up a bit then veer but also will be much more gusty, this doesn't seem to show up on the gribs.
...........

I do not know how being a HAM helps with Wefax – but please tell me. I have always understood that HF marine or HAM with a modem could only be used for emails – ie for GRIB files and text retrieval – to query@saildocs.com.

I do not know if Saildocs provides gust forecasts. I do know that the data are there. If you can use zyGrib, there is an option to select gusts.

When using GRIBs always remember that the GFS tends to underestimate the strongest winds. . This is because they use grid of about 27 km and, in any case, only provide data on a 50 km grid.

 

[ShinyShoe]

Receiving signals will have little to do with if the set is a receiver or a transceiver. A 'proper' HAM set may well be tweaked a bit better internally to optimise the signals. The biggest advantage is likely to be that a ham set has a bigger external aerial. If you could attach the same aerial to a small transistor type set you may well get a similar benefit. So having HAM means you *might* improve the quality of the fax reception.

HAM however lets you send a message to someone else... which they can then respond to (or an automated service can) Thats what I understand happens with the grib files. Don't know if any service just sends grib files on a broadcasting schedule like weather faxes are so you don't need to ask for them?

@GHA - what bluetooth sound system are you using?

 

[GHA]

I do not know how being a HAM helps with Wefax – but please tell me. I have always understood that HF marine or HAM with a modem could only be used for emails – ie for GRIB files and text retrieval – to query@saildocs.com.

I do not know if Saildocs provides gust forecasts. I do know that the data are there. If you can use zyGrib, there is an option to select gusts.

The ham radio helps recieving wfax just by being a better radio with better filters, though surprisingly little in it compared to a degen 1103, for the money that really is a great little box. I think the ham RMS winlink system uses saildocs.

Ta for the gust info, looks like you're right, saildocs files don't have the gust info but zygote do. Haven't played with the latest Opencpn grib plug in but it looks quite advanced now..

http://opencpn.org/ocpn/grib_weather_plugin

 

[GHA]

So having HAM means you *might* improve the quality of the fax reception.

It does, I've tried it. on a ic7000 anyway even using the same backstay antenna, the selectivity is better and the digital filters help clean up any noise. But not a massive amount but might mean making a very weak signal readable offshore.

Don't know if any service just sends grib files on a broadcasting schedule like weather faxes are so you don't need to ask for them?

No go there, gribs need to be exact, recieve only means no error checking so you need a transceiver to get them via HF.

@GHA - what bluetooth sound system are you using?

JUSTOP btr006 going from tablet to a class d cheap but excellent amp for music and videos etc on the tablet, works great, getting audio back into the tablet doesn't seem possible via bluetooth yet, all the transmitters I've seen use the A2DP profile which android doesn't seem to be able to recieve.

 

[franksingleton]

Thank you about HAM and wefax. New to me, but I am not an HF/SSB user.

I know of no broadcast GRIB service. In principle it would be possible but I cannot imagine one being provided with the current 1950s technology of RTTY/SITOR. Such a service would really require high speed satellite communication systems.

As far as I understand it, Winlink users send an email requesting text off a web page. This is a text retrieval system similar to that provided by Saildocs. Winlink has a standard list of web pages – a rather out of date one is at http://weather.mailasail.com/Franks-Weather/Winlink-Catalog-Links.

Anyone can get texts off web pages using the Saildocs text retrieval service; it is not restricted to HF/SSB radio users. Winlink users can also request GRIB files by email in the same way that anyone with email access can do. There is a fair amount of commonality between the Saildocs and HAM Winlink systems; not surprisingly there is some commonality between Winlink and Saildocs developers.

 

[GHA]

This might be of interest to some...
Wfax users guide to abbreviations and much more.
http://www.opc.ncep.noaa.gov/UGbegin.shtml


And Frank, mid Atlantic alone it was a comfort to see someone's name on the incoming fax, nice to know somebody who knew what they were talking about had a hand in what you based your weather guesses on, we're you ever involved with that? Did "singleton" ever appear in the "forecaster" box?

 

[franksingleton]

This might be of interest to some...
Wfax users guide to abbreviations and much more.
http://www.opc.ncep.noaa.gov/UGbegin.shtml


Your point about knowing that a human being had a hand in a forecast is a good one. That is why I always stress the value of human input into GMDSS services. But, no my name never appeared. The UK did not then and still does not put the name of the forecaster on its output.