Weather for Lowbandwidth/Satphone Users?

demonboy

demonboy

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Joined
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Indonesia
www.youtube.com
WAIT!!!

Before you shout "try searching the forum" and "this has been covered so many times already" let me assure you I have done a search and it seems the search facility does not accept booleans so I'm getting a whole load of rubbish when I search for this topic.

I would like to save a few tabs as my homepages on my browser which load up low bandwidth weather pages for my specific area (Red Sea to start with). In particular I'm interested in 5 day forecasts and synoptic charts for large areas.

I'd also like to hear other tips and tricks for weather forecasting via satphone. Yes, I know it's been discussed many times before but we're leaving in 10 days so I'd like to get this licked.

Any help/pointers/links to previous threads appreciated.
 
Yeah, I have that saved as one of my homepages already. I'm not that impressed with it as it is a whole bunch of image files that have to be viewed individually. The Red Sea, for example, is a whopping 600kb. I could create an Action in Photoshop to animate them but I don't envisage downloading these files every few days, it's just too much for the old satphone credit :(
 
Have you had a look at Ocens.com? I used their stuff a few years back over Globalstar and it was very quick and easy and, given the call charges saved, not massively expensive either.

http://www.ocens.com/wxnet.htm

Mailasail also have some weather info, but not as comprehensive as Ocens.

Both of the above have good email compression stuff too.
 
another way of getting GRIB files in data form is by using "zygrib" (just google for their site)

I have never checked directly zygrib grib file size against the equivalent Ugrib (www.grib.us) file size, but many people say it is definitely smaller

maybe worth having a look ?
 
I tried Zygrib but found the software quite clunky. However I have heard of problems downloading a grib via satphone on gribus so maybe I need to look in to downloading via Zygrib to view in gribus. Thanks, roberto.

Anyone have any experience of comparing these two on a satphone? :confused:
 
I found I could download gribus over iridum no problem - then it all changed, what I don't know as it wasn't at my end, but know I can't get gribus via iridium.

Mailasail use the Meteo France forecast its fast and pretty acurate - down load the area map first though while you still have good comms.

What about weatherfax? some good stuff out there for free and you only need a MF/HF receiver, which I think you'd have heading off to Cochin?
 
Roberto said:
another way of getting GRIB files in data form is by using "zygrib" (just google for their site)

I have never checked directly zygrib grib file size against the equivalent Ugrib (www.grib.us) file size, but many people say it is definitely smaller

maybe worth having a look ?
Click to expand...

I just checked, and the zyGrib files are only about 50KB for the the entire UK and Ireland (6 hour x 5 day forecast). I've got zyGrib running under Vista on my desktop and Xandros on my laptop.
 
Jamie - welcome back to UK

Have you considered using the NOAA satellites? The transmissions are freely available anywhere on earth on the VHF (Airband), 137MHz-138MHz. It is a wideband signal and communications receivers (Narrow-band FM) are not really suitable for the task but a VHF Band II broadcast receiver can be converted very easily, up from 100MHz to 137MHz (use an old car radio?) or you could purchase a kit or ready make receiver for a few pounds.

The received audio can then be fed into a laptop and decoded with freely available software downloaded from amateur circles on the internet.

General Google search:

http://www.google.co.uk/search?hl=e...1&ved=0CAkQBSgA&q=137+MHz+weather+fax&spell=1

Specialist Receivers:

http://www.digitalham.co.uk/equipment/R2ZX_weather_satellite_receiver.php

http://www.hamtronics.com/r139.htm

http://hans.mayer.tv/html/noaa137mhz.html


Specialist antennas are not really required as the signal from an overhead pass from a NOAA can be received very easily on a hand-held scanner with telescopic whip, you might even be able to receive it on a piece of wet string! :D

Of course, you can build your own circular polarised (CP) helix if you like? It is a warbling-chirping signal, monotonously repetitive, which increases in signal strength and then diminishes over time as the satellite passes overhead.

As a founding member of the Remote Imaging Group (RIG) can I steer you towards this web-site:

http://www.rig.org.uk/

Read the page called "Reception" and look at the images which are available from the Polar APT on 137MHz from NOAA. :)

Give VERY serious consideration to this mode as you will not need any form of internet access to receive these signals and they are freely available to you, on passage, in the middle of the Red Sea, Indian Ocean, Atlantic or Pacific or Southern Ocean; rain, fine, s**t or shine!

73 de G6UXD/MM (late of Ofcom and previously, many many years with the Radiocommunications Agency and the RIS) :eek:
 
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demonboy... I've set up an ftp script that I use with an Iridium sat phone. Gets GRIBs and also tif images from noaa. It is massively more efficient than using a browser.

The stuff is on my boat pc which is er.. on my boat. I'm in the UK for a few days but will send you the stuff when I get back to Grenada end of next week.

btw... HF receivers are cheap - it's transmitting that needs expensive kit. You can easily get one for £100 that'll do the job as long as there isn't too much interference from other electrics on the boat.
 
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Lenseman - sounds v.interesting. Is the stuff you mention similar to this http://www.xaxero.com/index1.html or this http://www.geo-web.org.uk/hard.html ?

I did have a browse around at this type of equipment some time ago and but didn't persue it further as a) it seemed to be several hundred £ worth of kit so may as well use sathpone and Ocens and b) it seemed to require a lot of power as a PC would need to be on all the time to record passes.

Despite all that, fascinating stuff I thought.
 
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David, thank you very much for the comprehensive response. Unfortunately I am now back in Marmaris. I say unfortunately purely from a purchasing point of view but I will take a look through your links later on today. BTW, when we last spoke we discussed my VHF installation. I went ahead and bought a new Shakespeare antenna and wired 213 down the backstay (down the mast was impossible). It's fair to say I now have the most powerful VHF transmission in the Marmaris Bay area, with fellow yotties claiming they could hear us over 30 miles away, behind two (very large) mountains! :cool:

Jeannius - if you could supply me with that, that would be genius. Thank you :)
 
The simpliest and best way is to get the gribs over sat phone is from Saildocs into a program called viewfax. We have been doing this several years all over the world via iridium. The gribs from Saildocs are free, and they offer pretty much all the models available (including for instance the gulf stream current gribs) and all the layers (rain and waves and 500mb), and complete worldwide coverage. Viewfax is also free and excellent, developped with dirst input from Stan Honey (winning navigator in last volvo race)

So, (1) download viewfax - go to http://www.siriuscyber.net/wxfax/ - I would recommend the beta version as it has a neat way to get big weather files if you are connected to wifi, but it does not have a full help file like the 'rpoduction' version.
and (2) go to http://www.saildocs.com/ to get instructions on downloading gribs.

You can then get your gribs in two ways: (1) you send an e-mail grib request (a one line e-mail in a specific format described on their website) and you get a grib by e-mail back in about 30 seconds, or (2) if you are connected to wifi, with the viewfax beta version you can get the gribs directly (in the file menu click on the 'get data' function).
 
estarzinger said:
The simpliest and best way is to get the gribs over sat phone is from Saildocs into a program called viewfax. We have been doing this several years all over the world via iridium. The gribs from Saildocs are free, and they offer pretty much all the models available (including for instance the gulf stream current gribs) and all the layers (rain and waves and 500mb), and complete worldwide coverage. Viewfax is also free and excellent, developped with dirst input from Stan Honey (winning navigator in last volvo race)

So, (1) download viewfax - go to http://www.siriuscyber.net/wxfax/ - I would recommend the beta version as it has a neat way to get big weather files if you are connected to wifi, but it does not have a full help file like the 'rpoduction' version.
and (2) go to http://www.saildocs.com/ to get instructions on downloading gribs.

You can then get your gribs in two ways: (1) you send an e-mail grib request (a one line e-mail in a specific format described on their website) and you get a grib by e-mail back in about 30 seconds, or (2) if you are connected to wifi, with the viewfax beta version you can get the gribs directly (in the file menu click on the 'get data' function).
Click to expand...


fwiw I second viewfax, it's the only grib viewer (so far, apparently this function is under development at zygrib) that allows retrieving 500hPa heights and temps too, and it also has an impressive collection of official text bulletins, metarea, coastal, etc, fax images..
Never used with Iridium though.
 
estarzinger said:
The simpliest and best way is to get the gribs over sat phone is from Saildocs into a program called viewfax...
Click to expand...

Yep, I'd identified this one as a good possibility (see my post, above). I was playing with it last night and it's pretty easy to set up and I was just using GribUS or Maxsea to view the files. I will dload viewfax to play with.

One thing I'm struggling to get my head around is whether the services from one very high profile satphone coms company are any better than the service you suggest, estarzinger. I've just been directed to an alternative service: G-comm. Does anyone have any experience with them?

Essentially I just want fast weather information and the ability to update my blog, which I do using Blogdesk (brilliant bit of kit with superfast connectivity). I don't really care about email per say as those who want to get in touch with me can do so by texting me on the satphone and any update to my blog automatically emails my friends.

So email is only used to send a request for weather information; I am therefore relying on gmail to send my request and my own mail server to receive the email. Is the time spent connecting to these services really that much longer than connecting to a dedicated compressed mail service? I've been told these specialist compressed email services are 20 times faster. Maybe there are other free email servers I could consider?
 
Not too sure how it compares to what is available today over Iridium, but when I used the Ocens stuff with Globalstar fours years ago, during a one minute connection I could send/receive about 20 mails and get the latest grib. For full set of synoptic charts and sat imagery, IIRC, the call time was under two minutes.
 
demonboy said:
So email is only used to send a request for weather information; I am therefore relying on gmail to send my request and my own mail server to receive the email. Is the time spent connecting to these services really that much longer than connecting to a dedicated compressed mail service? I've been told these specialist compressed email services are 20 times faster.
Click to expand...

The two big iridium compression services are Global Marine Net and UUPlus, and third option is Airmail/sailmail which is optimized for SSB but also works well for sat phones. They all work about the same and cost about the same. Sailmail/airmail might be a little easier if you are really only going to use it for weather because they have the viewfax module built right into the e-mail client.

These serviced do two things: (1) the compress the body text of the message. If you are really only getting gribs, those are already as compressed as can be in their native format, so there is no extra compression gain. BUT (2) they also strip off a ton of header information that comes along with normal e-mails. For a normal plain text e-mail, we pretty much never see 20x compression but 5-10x is not unusual. For a grib request e-mail (which is only a short sting of text in the body), in normal plain text format the grib request e-mail is 5kb, after stripping off the header it is 3kb, a 40% gain. The return e-mail with the actual grib data is usually about 10kb for us compressed/header stripped and 13kb in 'normal e-mail' (so a 23% gain).

One other advantage of these compression services is they are very very good at keeping spam off their servers, so you don't end up paying to receive spam.

There is a simple breakeven calaculation to be done to decide if it is worthwhile to pay for these services. With the sort of grib only e-mails you are thinking of very roughly if you do more than 60 minutes a month it is a clear win - which would mean getting serious weather every day. If you use it for more normal e-mails, where there is more compression, the breakeven is much lower, more like 15 minutes/month.
 
OK, so the next question is what companies out there offer these services? Based on Nigel's reply I checked out Ocens and I noticed they too do email compression, so does this mean I am not restricted to the one very high profile satphone coms company to which I referred earlier?

I avoided a rant in my previous thread but I am getting utterly fed up with the way one particular company is treating me (like a five year old) and would prefer to take my business elsewhere. I have an unused SIM card supplied by one company. Can I activate and pay for my minutes with another company?
 
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