Comment: Handheld Satellite Phone Solutions for Travellers

Just one comment: IMHO if relying on satphones to get help in an emergency, consider this point, if a satellite is hit by space junk and is put out of action, will the system still function? Or are you going to be left waiting for ages (if ever) for the satellite to be replaced? Therefore it seems to me that only low orbiting satellite systems are to be considered, Iridium and Globalstar. Iridium has 66 satellites in orbit, Globalstar about 45, but increase is planned. I think that it is prudent to carry an EPIRB as well.
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Reply By: Bruce M - Friday, Sep 27, 2013 at 17:44

Friday, Sep 27, 2013 at 17:44
Derek

In fact the only satellite ever hit by space junk was, if my memory serves me correctly, Iridium.

Iridium and Globalstar are in low orbits, through which many rockets pass as they head for higher orbits. So their exposure to the risk of collision with space junk is higher than for GEO satellites orbiting at around 36,000 km altitude.

The 66 Iridium satellites (and 48 Globalstar satellites) are not mutually redundant. Each is like a mobile phone tower in the sky. If one dies, for whatever reason, there is a gap in the network's coverage until it can be replaced. That's why these systems have in-orbit spares, which can be relatively quickly maneuvered into position to replace the defective satellite.

GEO satellites, on the other hand, are orbiting so high that a collision with space junk is less likely. I am not aware that there has ever been one. Larger operators (ie those with more than one satellite in service) will have additional satellites in service that can, in the event of a defective satellite, be moved to cover the gap. At the moment, Thuraya has just one satellite in operation. Inmarsat has many.

Bruce M

AnswerID: 518814

Follow Up By: olcoolone - Saturday, Sep 28, 2013 at 09:41

Saturday, Sep 28, 2013 at 09:41
Also GEO satellites are more stable, are higher quality and have a more commercial value then LEO satellites.

The voice and data quality of GEO based services are way better then the LEO based services.

We have a few satellite services using Optus GEO (Optus) satellites and a few using LEO (Iridium).
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Reply By: Member - Stephen L (Clare SA) - Friday, Sep 27, 2013 at 19:14

Friday, Sep 27, 2013 at 19:14
Hi Derek

I do not want to start a muck fight, but in the event of an emergency and satellites were taken out, all our Emergency beacons, just like our Sat phones will not work....they rely on satellites as well, and even our GPS systems would not work either, so no one will know exactly where they are.

It would then be back to old faithfull.........HF radio as your lifeline to the outside world.

Cheers


Stephen
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Follow Up By: Member - Derek O - Friday, Sep 27, 2013 at 19:45

Friday, Sep 27, 2013 at 19:45
Spot-on Stephen, that's why my old Codan stays firmly fixed in my camper. But not everyone is au fait with HF, you just need listen to some of the galahs on the major HF network, talking over each other, ignoring people trying to get in.

But the probability of a major satellite wipeout is very remote, unless it is an act of bastardry in terrorist or wartime operations.

So for the "newby outback traveller" I would suggest the Iridium or Globalstar systems where there are many satellites in orbit, all-be-it closer to earth and rockets. Space junk is not solely composed of man-made debris, there is quite a bit of natural junk too, mostly small, but still capable of crapping out a satellite. And I would also recommend the EPIRB as last resort.

Cheers
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Follow Up By: Member - Derek O - Friday, Sep 27, 2013 at 21:59

Friday, Sep 27, 2013 at 21:59
Hi Stephen, something I forgot; back in mid 1980s work was being done developing an HF location system. SKYLOC, by SA interests. I was doing a trip north, so offered my services as the "Needle-in-the-Haystack" transmitting on 3 frequencies at midday, 3 frequencies at 9 pm. Much as I tried, hiding in gorges etc, they always located me, no doubt helped by knowing where my last transmissions came from, but generally pretty impressive.

I never followed up on the final outcome, but if SKYLOC was made an ongoing commercial system, it would have been very reliable. Who knows, it may still be there.

Of course, that was nearly 30 years ago, and a lot of changes have been made in the HF arena since then; the OTC network disbanded, Telstra Radphone network closed (thanks to luddites like John Howard, Ziggy Switkowski and Coy.).

Just a bit of historuy, you may appreciate it.

Cheers.
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Follow Up By: Member - Stephen L (Clare SA) - Friday, Sep 27, 2013 at 23:13

Friday, Sep 27, 2013 at 23:13
Hi Derek

Thats very interesting, was it for the military?

I am now a big fan of sat phones, owning an Inmarsat. Have said that, there was an article a good number of years ago in the VKS Newsletter about an issue with the satellite systems going down before a weekend, and no one could use their sat phone until the issue was fixed a few days later, showing the importance and reliability of HF radio.

Like all things, we all rely on all satellite systems greatly and if someone did turn them all off, there would be many people in great trouble.


Just think, we could not even use OziExplorer......


Cheers


Stephen
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Follow Up By: Member - 38south - Saturday, Sep 28, 2013 at 19:02

Saturday, Sep 28, 2013 at 19:02
All communication modes have advantages and disadvantages.
If you use HF, it could be useful to have a spare aerial and a tool to fit it... or a bit of fencing wire.
The aerial can be lost/wiped out by a tree or some such.
Also HF relies on a large electrical supply, no battery no HF.
HF also relies on the vagaries of HF propagation and someone being there to receive. A colleague laments that trying to get information by HF radio about weather and when possible to leave Dalhousie Springs, found that there was no useful communication. (Not sure what network or frequency used).
A satellite (and mobile) phone can be charged from a palm-sized solar charger, should your vehicle loose all electrical power.
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Reply By: Member - Boobook - Saturday, Sep 28, 2013 at 06:23

Saturday, Sep 28, 2013 at 06:23
We should also be concerned that an Alien will come and take away the satellites, and therefore not rely on them.

Too risky.

Also don't watch TV, make a phone call, rely on weather forecasts, or look at google maps anymore.

You can never be too careful I suppose.
AnswerID: 518844

Follow Up By: olcoolone - Saturday, Sep 28, 2013 at 09:35

Saturday, Sep 28, 2013 at 09:35
I think I'll just stay home....... what happens if they get to the electricity and what about Foxtel!....... AND fuel?

Looks like the end is near for ExplorOz...... there will be 1000's who will have to attend EOA for counselling.
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Follow Up By: Member - Boobook - Saturday, Sep 28, 2013 at 10:24

Saturday, Sep 28, 2013 at 10:24
There is a chance that the space junk that hits the comms satellite will bounce off it, heading directly into your home.

You can't go out, you can't stay in.

I know the answer

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Follow Up By: Member - Michael A (ACT) - Saturday, Sep 28, 2013 at 17:31

Saturday, Sep 28, 2013 at 17:31
Yep and the little green men will come and place a transmitting bug in your skull and we will always be able to hear each other. then joy oh joy we will never be free arrrrrrgh

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Follow Up By: Member - Derek O - Saturday, Sep 28, 2013 at 20:15

Saturday, Sep 28, 2013 at 20:15
Hey guys, seems we have a couple of streams running here, and a bit of farcical humour thrown in as well.

If you want chit-chat, sure go for your satphone, but in an emergency you need as many strings to your bow as you can muster: hence a satphone that is connected to a myriad of satellites, not just one or three; an EPIRB, when all else fails, antennas broken, satphone battery flat and won't charge; and if you know how to use one properly, an HF radio and access to one of the HF networks.

In rainforest, in gorges, an HF radio will get out; satphones have problems in rainforest due to foliage impeding the signal., gorges limit satphone access to satellites, sometimes completely blocking the signal. I am not sure about the 400 meg EPIRB in rainforest, but gorges seem to offer few problems due to reflections off walls.

So basically it boils down to how much insurance you are prepared to buy; I carry HF plus EPIRB (and a UHF for nearby comms); I don't fancy the idea of perishing through lack of water in inland Australia because my communications "insurance" is inadequate.
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