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Technology Stocks : Winstar Comm. (WCII) -- Ignore unavailable to you. Want to Upgrade?

To: SteveG who wrote (3095)	12/10/1997 5:33:00 PM
From: David Krafcsik	Read Replies (1) \| Respond to of 12468

<..I have read where the effect of rain is countered by kicking up the transmission wattage or something...> << I THINK (but am not sure) that attenuation of many types can be addressed by increasing the bandwidth (range of frequencies) transmitted through. David? Steve >> I suppose it depends on what kind of modulation scheme they are using. It sounds like phase modulation, and I think they are limited to a set bandwidth by the FCC allocations, so they can't really change that. They could always increase the transmission power to ensure they had an adequate SNR (signal to noise ratio) for all possible weather conditions. The key point is that at 38 GHz the variability in signal attenuation due to water in the atmosphere is much less than at say 28 GHz. Hence you wouldn't have to pump as much power through (means smaller power transmitters) and you probably wouldn't need as much dynamic range in your receiver. Increasing the bandwidth to handle different types of interference sounds like a spread spectrum kind of approach. Is that what you were talking about? I don't think they can use spread spectrum because of the way these frequency bands are allocated.