>I have often wondered, if the LP design for Military/Embassies, was
>selected for broadband capabilities, which might be needed if secure HF
>comms used/needed spread spectrum modulation, back in the "olden days" of
>comms over HF.
Using skywave propagation the optimum frequency for transmission from point
A to point B can vary 5 to 1 considering time of day, season, and solar
activity year. The rotatable LPA solves a lot of antenna problems. As to
spread spectrum, the skywave path is not very broadband. The 'Woodpecker'
used a four frequency sequence, frequency hopped every second or more but at
any time the frequencies selected were within a 2 MHz bandwidth. And the
useful coherent bandwidth may be only 100 KHz at best.
>Someone once told me, that, long before Spread Spectrum became familiar
in the ham radio vernacular, that the term "Spread Spectrum" was itself
classified, could not even be said openly, among the military/spook crowd.
I don't remember the words 'Spread Spectrum' being classified. Classified
words generally were not truly descriptive.
73, Jim w3cp
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