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From: rcarpen@lan2wan.com
Subject: Wideband SS EME
Date: Sun, 01 Dec 1996 08:45:32 -0800
More quoted from the KA9Q/W3IWI paper.

"A ... fundamental problem [with higher power and higher data rates] is the inherent EME delay spread of several milliseconds. If the symbol interval is shortened to where the delay spread becomes an appreciable fraction [of the symbol duration], intersymbol interference appears. The best way around this is to frequency hop ... from symbol to symbol to allow time for the limb reflections to die out on a given frequency before it is used again -- and this means still more total bandwidth.."

"So it seems pretty clear that the potential of a conventional (large) EME station can be fully realized only with a true spread spectrum signal."

"On the other hand, scaling this technique to even smaller stations runs into more fundamental problems." [Discussion of the much lower data rates allowable and long times required.] "And it would certainly tax the patience of most operators since our scheme necessarily gives no real feedback to the operator until after an entire transmission has been transmitted and received."


>From this I conclude that it is only the BIG GUNS who will have enough 'smoke' to use wide SS for EME.

73 de Bob w3otc ------ Submissions: vhf@w6yx.stanford.edu Subscription/removal requests: vhf-request@w6yx.stanford.edu Human list administrator: vhf-approval@w6yx.stanford.edu