[TowerTalk] Spread Spectrum

[JAMES HEADRICK]

>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