<span class="highlight">Thuraya</span> sat phone coverage ?
Submitted: Thursday, Oct 23, 2008 at 12:29
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Member - Footloose
With the launch of their new satellite,
Thuraya claim to have coverage of all of Australia. (We've heard that before, haven't we?)
Unless I'm missing something, those little aerials don't appear too promising in the bush, especially with any canopy around. Yes I understand that they are new technology but...
Do we have any actual reports of the performance of these units in the bush yet ? Anyone used one on a trip?
Reply By: Wayne (NSW) - Thursday, Oct 23, 2008 at 14:41
Thursday, Oct 23, 2008 at 14:41
Footy,
I can't report on the
Thuraya Sat Phone, but I have noticed a very big difference with the sat phone that I use.
Before the external aerial getting a signal was hard and also hard to keep. After the car kit was installed and the external aerial connected the reception is a lot better and holding the connection has also improved.
I have always believed that for a short distance a short aerial will do but if you want to send or receive a signal from a long distance that bigger the better.
There is properly a lot of teco stuff that will prove me wrong in that theory, but I have yet to see a small HF aerial or a small UHF aerial that will go the distance and that also should apply to a sat phone.
Wayne
AnswerID:
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Follow Up By: Nomadic Navara - Thursday, Oct 23, 2008 at 16:42
Thursday, Oct 23, 2008 at 16:42
Big antennas produce bigger signals by narrowing the beam width. For CB antennas this narrowing of the beam is in the vertical direction, not the horizontal direction. If you use that style of antenna you will not get much signal up to the satellite. If you use an antenna that produces a narrow beam upwards then you have to steer it to keep the signal on the satellite..
PeterD
FollowupID:
599219
Follow Up By: Mike Harding - Thursday, Oct 23, 2008 at 17:52
Thursday, Oct 23, 2008 at 17:52
Wayne: antenna theory is amongst the more complicated area of electronics and I regret to tell you that your theory is wrong :(
In addition to the theoretical complexities of antennas the real world comes into play (especially with the high frequencies 200MHz+) and things such as local ground conductivity, mounting location etc. play a major part in the efficiency of the antenna. Modern computing capacity has provided a far greater ability to preform antenna analysis but we're a long way from perfection in this field.
Expert advice is useful but often the best thing is to try it and see if it works :)
Mike Harding
PS. PeterD; any chance of a response to the Amateur Radio/Type Approved thing...?
FollowupID:
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Follow Up By: Member - Footloose - Thursday, Oct 23, 2008 at 20:47
Thursday, Oct 23, 2008 at 20:47
Wayne, the hand-held Motorola's also come with an external magnetic mount aerial that tends to improve things.
I agree that a car kit will lift the usefulness of sat phones, but I'm not convinced that the service that you use is all that great to start with.
The main thing is that you're happy with it, and that's all that counts :)
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Reply By: Member - John R (QLD) - Thursday, Oct 23, 2008 at 18:32
Thursday, Oct 23, 2008 at 18:32
Hi Footy
As the geostationary satellite sits 36000 km above the equator, it can "see" all of Australia OK, though it must be pretty close to the horizon from southern Oz. Presumably most times you will just be able to move a bit to one side, if the canopy blocks access from your current position. There were some comments on usability back in post
61912
The antenna on the phones is a different matter. The frequencies are around 1.6 GHz, so maybe someone on the
forum can comment whether the size matters so much at those frequencies?
Cheers,
John
AnswerID:
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Follow Up By: Member - Footloose - Thursday, Oct 23, 2008 at 19:05
Thursday, Oct 23, 2008 at 19:05
Hi
John and thanks for you reply. I've re read that thread and got one or two things out of it.
1) They work in at least two
places
2) The handsets seem a bit "fragile" for bush use ?
3) At least someone's bought some.
A great pity that there wasn't more info in another follow up.
The aerial question wasn't as silly as it probably looked. At those frequencies bigger isn't always better, as a lot of gain can be packed into the aerial. But unless they have some form of pull out aerial, getting reliable comms with the head and ear in the way, might not be so easy.
It's not quite the same with a terrestrial service, where you can just move a bit.
I stand to be corrected on that one, it's nearly 40 years since I trained on microwave stuff :))
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Follow Up By: Member - John R (QLD) - Thursday, Oct 23, 2008 at 20:35
Thursday, Oct 23, 2008 at 20:35
Hi Footy, yep agree with most of that - will be better when more people have tried them all over Oz. If they do work OK though I'm interested, since they'd go much better (encased) in a backpack!
The phones do have a pull-out antenna for satellite use (rather than the rotating type on Motorolas)
Cheers,
John
FollowupID:
599289
Follow Up By: Member - John R (QLD) - Thursday, Oct 23, 2008 at 20:42
Thursday, Oct 23, 2008 at 20:42
Also this from the SO-2510 manual:
While idle with SAT or communicating with a good quality signal, the antenna need not be pulled out. However, the antenna should be pulled out to receive SAT calls or to start SAT.
While watching the indicator for SAT signal strength, move around to achieve the best connection quality for the mobile phone. SAT communication requires clear space without obstructions. Avoid obstructions such as buildings, trees or mountains. Also, it is important to direct the antenna of the mobile phone towards satellites.
FollowupID:
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Follow Up By: Member - Footloose - Thursday, Oct 23, 2008 at 20:51
Thursday, Oct 23, 2008 at 20:51
Hmm...I have to admit that I tend to stand still when using my phones, but perhaps thats because I already know the optimal spots to do so.
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Follow Up By: Member - John (Vic) - Saturday, Oct 25, 2008 at 01:58
Saturday, Oct 25, 2008 at 01:58
John R was that 36,000 km above the equator??
Whats the power output on the handset to transmit a signal that far??
And what sort of voice/signal delay would one experience when the words have to travel up and back that sort of distance me wonders??
Iridium Sat's are only 700 km above us.
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Follow Up By: Member - John R (QLD) - Saturday, Oct 25, 2008 at 19:56
Saturday, Oct 25, 2008 at 19:56
Hi
John, yes 36,000 km above ground, so the signal goes about 75,000 km up and back to the ground station. As the speed of light is 300,000 km/sec, then there would be about a 1/4 sec delay (plus the time to get the signal from the ground station to the phone you are calling). Don't forget though that the Iridium network passes your call from one satellite to another until it gets to one in contact with the ground station, so there can be a significant delay there as
well.
The power output is given as max 2 W in satellite mode, which is apparently similar to the max that GSM phones can put out. (this from a FAQ page
here).
Cheers,
John
FollowupID:
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Follow Up By: Member - John (Vic) - Saturday, Oct 25, 2008 at 20:48
Saturday, Oct 25, 2008 at 20:48
Thanks
John good info.
You got to admit thats an impressive combination of technology and electronic engineering to achieve those sort of distances with such low power output and such a small antenna
Not an ideal comparison but the old
UHF radio in the 4wd has only 5 watts of output and struggles to get 50 km's in ideal conditions.
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Reply By: RustyHelen - Thursday, Oct 23, 2008 at 21:09
Thursday, Oct 23, 2008 at 21:09
Hi all
Not any sort of authority on this matter but doing some research for our Club which has a sat phone for Member use and we are looking to replace as it is Globalstar.
Spoke with a seller in Vic just today and they mentioned this phone. The comment was much cheaper, yes offers Australia wide coverage but no good for anyone who might want intenational coverage and, the killer for me, you have to be facing north west (I guess that is where the satellite is??) with a view and not moving, not even walking or rocking, stand very still.
Maybe not the reliability you might need in a stress situation.
Rusty
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Follow Up By: Member - Footloose - Thursday, Oct 23, 2008 at 21:14
Thursday, Oct 23, 2008 at 21:14
Thanks Rusty. Interesting info if they're correct.
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Follow Up By: Member - Dunworkin (WA) - Thursday, Oct 23, 2008 at 23:36
Thursday, Oct 23, 2008 at 23:36
Thanks for that info RustyHelen, I have done a fair bit of research on these phones as
well and hadn't heard about that yet, very interesting. The phones are so new that it is going to be a while before a lot of real out in the field info comes in.
The info that has come in so far from a couple of Forumites hasn't been all that bad up to this point, still watching this space.
Cheers
D
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Follow Up By: Member - John R (QLD) - Friday, Oct 24, 2008 at 23:13
Friday, Oct 24, 2008 at 23:13
Hmmm ... If you were facing NW, then the antenna (as most people hold phones) would be pointing away from the satellite, exactly opposite the advice in the manual! No wonder you wouldn't want to move around at all. :-)
Do Optus maybe limit use to Australia only? The phone itself will work in over 100 countries (but definitely not US, or anywhere in the Americas).
Perhaps talk to some other sellers, Rusty.
Cheers,
John
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