Seeking ideas for use of satellite phone

[SALT108]

Further to my post at http://www.cruisersforum.com/forums/...ia-115866.html

I am a programmer. I don't boat, but my friend has a yacht.

I mentioned a cheap ($US600 or so) satellite modem, which which means communication anywhere at sea, even out of radio range, and he seemed interested.

It is cheap because it is "low data rate". That means no phone calls, but it is perfect for Machine To Machine communication. Approximately 1kB every second or two, but so long as we are in no hurry that an add up over a few minutes - just nothing real-time.

I can think of:

• Weather forecasts
• SMS
• Email (might have to be text only, no images)
• Possibly fax, if not in a hurry
• Distress beacon
• Regular auto-post of location to FaceBook/Twitter

Can you make more suggestions or what I might offer him?

Thanks for any help

[Littlechay]

Again, these are on the market already.. Just enter your questions as terms in google

[SALT108]

Oh, I "sea". Not being ocean going, I was not aware.

I will obviously google, but am unsure what I should be googling for. Is there any other nice stuff which I should be aware of?

I would like to program something to help my friend, but, as you said, no need to reinvent the life belt.

I guess I will see if all of these have a free edition, if not, I can code one. If so, maybe I can "value add" by packaging them all into one app.

Just from curiosity, is there anything that is missing? If you had a satellite modem on board, is there any feature which you would like that is not currently available (free or cheap)?

Thanks again. I'm off to Google now

[rebel heart]

Check out uunet. The handshake and connection is really expensive, so you want to get as much as you can on every hookup. Compressed email, compressed weather charts, news as text files, etc.

[Auspicious]

Originally Posted by SALT108

I can think of:

• Weather forecasts
• SMS
• Email (might have to be text only, no images)
• Possibly fax, if not in a hurry
• Distress beacon
• Regular auto-post of location to FaceBook/Twitter

Weather forecasts: Google for rfax.pdf, then Frank Singleton (the mailasail site), and HF voice at the USCG Navcen site. Those will all lead you on to other resources.


Location: Learn about Winlink location services, YOTREPS, AIS (Shiptrak and Marinetraffic), APRS, and Spot.

[Littlechay]

For free weather display look for ZyGrib, free and open source charting look at OpenCPN which also displays weather (sort of).

Instead of a satellite modem you can also get all this information using a HF Pactor modem. Have a look at the Sailmail site as a starting point (the Airmail programme also has a built in Fax and Grib viewer; simple but good.)

Good luck

[SALT108]

Originally Posted by rebel heart

Check out uunet. The handshake and connection is really expensive, so you want to get as much as you can on every hookup. Compressed email, compressed weather charts, news as text files, etc.

Thanks. Of course, I was unaware of this.

It sounds like something which I want to emulate, or better, as cheaply as possible, for my friend - and why not for public domain?

[SALT108]

Originally Posted by Littlechay

For free weather display look for ZyGrib, free and open source charting look at OpenCPN which also displays weather (sort of).

Instead of a satellite modem you can also get all this information using a HF Pactor modem. Have a look at the Sailmail site as a starting point (the Airmail programme also has a built in Fax and Grib viewer; simple but good.)

Good luck

"HF Pactor modem" - really? Even beyond the horizon? Or dozens/hundred of miles out? I really am a dunderhead ;-) I know little of hardware and less of boating. I just know how to program & that sat modems are the only option in remote land areas.

Are you thinning of receive only, or also transmit?

Thanks very much for your input.

[Littlechay]

I have a used a HF modem for weather and email from Antarctica to the tropics. Sure you have to set up the radio ( you can also use that keeping in touch on the cruisers nets by voice - for free ) and learn the basics on using it but the Airmail software (for example) includes a propagation prediction module.

BTW the only satellite system that covers all of the ocean is Iridium.

[SALT108]

But you are receiving only? Not transmitting, I imagine. [Ooops, I just read that you have email, so presume that you also transmit?]

And Inmarsat has coverage as good as, if not better than, Iridium

https://www.google.com.sg/search?q=i...erage&tbm=isch

[SALT108]

" a propagation prediction module" ... hmm, sounds like a "distributed network". A DTN (delay/disruption tolerant network) https://en.wikipedia.org/wiki/Delay-tolerant_networking

If it is not, that's also something which I (have worked on and) could make freely available.

[rebel heart]

Originally Posted by SALT108

Thanks. Of course, I was unaware of this.

It sounds like something which I want to emulate, or better, as cheaply as possible, for my friend - and why not for public domain?

You can, it's just a lot of grunt work. Some of those applications (like uunet) have been around for a long time so they've matured and there are a ton of features in them that represent many thousands of development hours.

It's also not trivial stuff. Some parts are simple, but handling the chunking and compression would be a pain. There's the server code, client install, and then the hosting cost of the mail/application server you'd need to maintain.

I've been writing software for over a decade and when I started using uunet for a little bit I just couldn't see the value in reproducing it, especially when I realized there was ongoing hosting costs.

[Littlechay]

both transmitting and receiving ... if propagation works one way it generally works in the other

Generally I do a morning and evening email send/receive (depending on propagation). First Tx/Rx includes a request for the GRIB that I want. Second Tx/Rx, about 10 minutes later, downloads it.

I use HF as a preference (free airtime) but if propagation just won't play I use exactly the same setup on Iridium.

Nothing can be better than Iridium as it has global coverage. INMARSAT does not cover high latitudes, physically impossible. And their services for small terminals is not that great in deep ocean areas. Same for Globalstar etc..

With INMARSAT as you get towards higher latitudes your antenna needs to get bigger. I have used INMARSAT to 70 South on Fleet 77 but i have heard that iSatPhone won't go that far south.

Iridium just works the same wherever you are.

[Littlechay]

Originally Posted by SALT108

" a propagation prediction module" ... hmm, sounds like a "distributed network". A DTN (delay/disruption tolerant network) https://en.wikipedia.org/wiki/Delay-tolerant_networking

If it is not, that's also something which I (have worked on and) could make freely available.

Google "VOCAP"
Many programmes have an interface to VOCAP built in.. Airmail for example

[nohal]

Originally Posted by SALT108

And Inmarsat has coverage as good as, if not better than, Iridium

https://www.google.com.sg/search?q=i...erage&tbm=isch

Tell this to the people in polar regions... Inmarsat has a couple of geostationary sats, Iridium has a lot of sats on polar orbits. That says it all. But unless you need it in extreme latitudes, Inmarsat serves at least as well

Pavel