Re: Spread Spectrum


 

On 1/28/2014 3:02 PM, John Stephensen wrote:


The publicly documented technical characteristics apply to RTTY and
data emissions but not to spread spectrum emissions. The developer of
ROS published a technical description for a spread spectrum emission
with a spreading factor of about 8. The FCC reviewed that document and
concluded that the emission was not allowed in the U.S. below 222 MHz.
Significant over simplification of what actually occurred.

Not going to re-debate this. Just that the NTIA / IEEE / industry
definitions of SS would exclude pretty much any Audio SSB based technique.

You may not like CHIP/ROS/whatever, but that does not mean they are
spread spectrum, nor make it a clear issue with the FCC.

Remember, the FCC informally commented on ROS "if the author says it's
spread spectrum, then it's not allowed". That is far from an engineering
review, etc. Not defending ROS, it was handled very badly in many ways.

And the FCC in past comments has indicated it does not find the US
amateur "angels on a pinhead" debates productive use of their time. Had
some very direct inputs about how we need to quit the infighting and
start working together. (Gee, same general issue triggered that
comment... data on HF)

So if you want to comment against use of modes, do so. But let's not try
to overinterpret the regs. The 222 mhz restriction was put in place
regarding traditional 70's tech (100 khz+) DSSS with spreading factors
of 15-25. That rule was made long before anyone envisioned the DSP
techniques that would allow some of the audio level SSB bandwidth
techniques we now use.

To an RF engineer the idea of audio based SSB being DSSS is laughable at
best.

Just makes me sad that US Hams fight so hard to limit our capabilities
and hinder new development.

Have fun,

Alan
km4ba

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