Thanks for the clarification, Rein.
That agrees with what Steinar sees, and with the Wikipedia discussion,
which says in part, "Most pseudorandom generator algorithms produce
sequences which are uniformly distributed
</wiki/Uniform_distribution_%28discrete%29> by any of several tests. It
is an open question, and one central to the theory and practice of
cryptography </wiki/Cryptography>, whether there is any way to
distinguish the output of a high-quality PRNG from a truly random
sequence without knowing the algorithm(s) used and the state with which
it was initialized."
The differentiating factor in FHSS is apparently whether or not the data
is superimposed on the carriers, or if the carrier frequencies are
determined by the data. I cannot see that happing in ROS, and I can in
all the FSK modes, but maybe I just do not know how to find it for sure.
I guess the FCC engineers will probably figure out if ROS is actually
spread spectrum as originally claimed, or FSK with FEC as now claimed.
It is just hard to imagine that someone as intelligent and capable as
Jose could make such a huge mistake after writing seven pages of text
and diagrams describing the mode the first time! No wonder the FCC
believed him! Will they now believe him, or will they believe that the
so-called "technical description" now on the ROS website is just an
attempt to get ROS considered legal on HF? Probably they will believe
only their own tests now, so we will have to wait for those.
The FCC does not care about the "mode", or what it is called, but only
what is transmitted on the air.
73 - Skip KH6TY
pa0r wrote:
SS uses pseudorandom codes to wag the carrier(s).
EVERY pseudorandom code is repetitive, the length may vary.
73,
Rein PA0R
--- In digitalradio@yahoogroups.com
<mailto:digitalradio%40yahoogroups.com>, KH6TY <kh...@...> wrote:
>
> That's a good analysis, Steinar. Is it possible to see if the pattern
> changes when sending data? That is all the FCC is concerned about. The
> pattern has to change when sending data and not just remain the same to
> exclude it from being FHSS.
>
> 73 - Skip KH6TY
>
>
>
>
> Steinar Aanesland wrote:
> >
> > [Attachment(s) <#TopText> from Steinar Aanesland included below]
> >
> > Hi Skip
> >
> > I have been monitoring a ROS idling over time using DL4YHF's Spectrum
> > Lab. Here is the results.You can clearly see a pattern
> >
> > 73 de LA5VNA Steinar
> >
> > On 26.02.2010 12:29, KH6TY wrote:
> > > Alan,
> > >
> > > Of course, the FCC rules on SS are outdated and ROS should be
allowed
> > > due to its narrow spreading range, but the road to success is not to
> > > just rename a spread spectrum modem to something else and try to
fool
> > > the FCC. This is a sure way to lose the battle. The genie is already
> > > out of the bottle!
> > >
> > > Instead, just petition the FCC for a waiver, or amendment, to the
> > > regulations that are a problem, to allow FHSS as long as the
spreading
> > > does not exceed 3000 Hz and the signal is capable of being monitored
> > > by third parties. Do this, and there is not a problem anymore.
But, do
> > > not try to disguise the fact that FHSS is being used by calling it
> > > something else, as that undermines the credibilty of the author
of the
> > > mode and will make the FCC even more determined not to it on HF/VHF.
> > >
> > > It looks to me that the tone frequencies are clearly being generated
> > > independently from the data and then the data applied to the
randomly
> > > generated frequency. There is NO pattern to ROS like there is to FSK
> > > modes, even to 32 tone FSK (Olivia 32-1000) or to 64 tone FSK
> > > (MT63-2000). This is a signature of FHSS.
> > >
> > > âEURoe/If/ it walks /like a duck/, quacks /like a duck/, /looks
like a
> > > duck/, it must be a /duck/âEUR?.
> > >
> > > It looks like ROS really is FHSS when you look at it on a spectrum
> > > analyzer, and the spectrum analyzer does not lie.
> > >
> > > 73 - Skip KH6TY
> > >
> > >
> > >
> >
> >
>
