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Microcap & Penny Stocks : Globalstar Telecommunications Limited GSAT -- Ignore unavailable to you. Want to Upgrade?

To: Clarksterh who wrote (4380)	5/1/1999 12:01:00 AM
From: Maurice Winn	Read Replies (1) \| Respond to of 29986

* This post is corrected in the next post - Link Margin Jargin * I'll leave it here in case anyone else who doesn't understand link margins gets silly ideas like this. Iridium has better connection than Globalstar! [I recall this earlier in the thread now] -------------------------------------- Clark, just a guess, but Globalstar connection should be much more robust than Iridium's. The handset will blast signal out through the concrete tile roof of a house like tissue paper. It has got to travel a long way with heaps of signal reduction with the square of the distance tiring the signal out every doubling of distance travelled. Over 1,414, at least, but usually more like 1,800 km, there are a LOT of doublings. So a handset in a building will blast much better through a wall or non-metallic roof than a terrestrial handset will do, because the proportion of the signal needed to get through the material will be relatively small. For the satellite signal coming back, I'm not so sure that the Globalstar handset will be as well off and you suggest not. The satellite signal down is weak and needs an open air handset but wouldn't the same argument apply as for the handset? Standing outside in the rain will mean there is a metre of pure water to be transmitted through whereas if they stand inside, there is no rain on their head and the extra 5 cm of building material [non-metallic] won't matter much compared with the path length and rain drop attenuation. Then there is the multipath advantage. Once the next lot of satellites is up, this advantage will compound because there will be satellite peering in all over the place. It'll be like having the Paparazzi after an image of Princess Di in the shower - it will be hard for her to keep them out of sight [and Globalstar satellites can see through walls]. Maurice PS: Thanks for Thatbitextra Andmoreagain. Just how many leaves does it take to equal 1800 km and a bunch of dirty, wet atmosphere? How about in autumn when the leaves are off? What about sending a signal through a window [not double glazed]? Trust you? But you said not to? Which of you do I trust?

To: Clarksterh who wrote (4380)	5/1/1999 12:13:00 AM
From: ElTombo	Read Replies (2) \| Respond to of 29986

I've been reading a lot of posts lately about how globalstar phones won't work well inside a building, or in a metropolitan area with tall buildings. I would think that a globalstar phone would always work at least as well as any regular cell phone since you could always use the dual mode on the phone, and connect through the terrestrial cellular network. Correct me if I'm wrong here. ElTombo

To: Clarksterh who wrote (4380)	5/1/1999 12:48:00 PM
From: CommSatMan	Respond to of 29986

Clark - You are absolutely correct. I previously talked about the differences between terrestrial cellular and space-based cellular, specifically pointing out that power control is one area of concern. G* says they have accounted for the problem and have a solution. I am skeptical, because it directly impacts capacity, but I am willing to give them the benefit of the doubt. In a transponded satellite, signals that are 6 to 10 dB lower, typically get suppressed further. It's called small signal suppression and results in too low of signal to maintain reliable communications. Power control is one area that is critical to preclude this and the millisecond delays in adjusting because of the system characteristics is an important factor to consider. The other area has to do with raising the noise floor. You have a similar problem with small signal suppression and really becomes one of the limiting factors for the number of simultaneous users you can support in a single band. The use of CDMA in space reminds me of another technical dilemma. In the late 70s, Bragg Cell receivers were going to replace Compressive Receivers for all wideband communication applications. However, there was a simple law of physics that could not be overcome that really limited the utility of the Bragg Cell receiver. One could get extremely wide bandwidth coverage instantaneously, but with a limited dynamic range or one could get less bandwidth coverage and have a large dynamic range. Physics would not allow both, so the Bragg Cell for all the hype became a more limited receiver. Space based power control for CDMA is a little like this in that you can do lots of things except change the speed of light and therefore how long you have to react to fast fading conditions. I have no doubt CDMA will work in space, however, IMO the same levels of capacity realized on the ground will not be seen because of the physical factors involved. I do not think this renders G* as a non-profitable entity, but I do think that the COGS (related to capacity) is higher than anticipated, so the profits won't be as much. It's just hard to quantify until the system is operational and the actual loading impact can be measured. CSM