Re: Spread Spectrum


On 1/26/2014 1:06 PM, John Stephensen wrote:

The FCC regulations list what is allowed and everything not listed is
banned. The table in the authorized emission types section (97.305)
only references spread spectrum for frequencies above 222 MHz.

May want to go back and read the archives. You answer is overly
simplistic, and not really even accurate.

The issue is not the regs, it's the fact that interpretation of what
is/is not SS varies widely by hams. The regs do not address that, nor
will the FCC. While there is an attempt to call any chip modem,
randomizer, or audio level DSSS techniques to be SS, that is not backed
up by the engineering definitions in the NTIA, IEEE, industry
terminology, etc, primarily based on the spreading ratio.

The reality is that the FCC ham regs address 70's tech DSSS with
extremely high spreading ratios that make them extremely wide band
(100khz or more). Theses technologies have to be handled at IF level,
and are completely different than the AFSK'ish modes currently being
debated. Those do meet the NTIA definitions, and are rightly banned
below 220 Mhz.

As an RF engineer, it's pretty laughable to try to compare the two. No
real SS can be done with a SSB ham rig!!! And I've provided multiple
sources for definitions to back that logic up.

So we are circular for about the 10th time. The crummy yahoo search
interface will help.. just look for km4ba and ntia.

Have fun,


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