Rik,
Did you see the recent post by K3DCW?
The closest you get to a true definition in Part 97 is in section 97.3
Definitions, Para C, line 8:
/(8) SS/. Spread-spectrum emissions using bandwidth-expansion
modulation emissions having designators with A, C, D, F, G, H, J
or R as the first symbol; X as the second symbol; X as the third
symbol.
ROS uses SSB so the first designator is J (this meets the definition)
and it uses bandwidth-expansion. (this meets that definition as well)
Thus, taking this definition literally, it is indeed Spread Spectrum
and is thus illegal below 222MHz....at least that the conservative
interpretation that I'll stick with until we get a ruling otherwise.
====================
Dave
K3DCW
Obviously, with such a new mode, there has been no ITU description of
ROS. If it used bandwidth expansion (i.e. frequency hopping), it is
obviously to be classified as spread spectrum. Whether or not modes like
MT63 and Olivia are essentially the same is debatable. The problem seems
to be the direct reference to bandwidth expansion (but within the width
of a phone signal), which, until ruled otherwise (and I hope it will be)
is spread spectrum according to the current FCC rules, and is currently
legal only above 222 Mhz.
73 - Skip KH6TY
Rik van Riel wrote:
On 02/21/2010 02:17 PM, w2xj wrote:
> I have spent the last hour looking through part 97. I find nothing that
> would prohibit ROS in the HF bands subject to adhering to those segments
> where the bandwidth is allowed. In fact the rules would appear to
> support such operation:
Lets look at it in another way. Part 97.3 is quite specific
about what modes are considered spread spectrum:
(8) SS. Spread-spectrum emissions using bandwidth-expansion
modulation emissions having designators with A, C, D, F,
G, H, J or R as the first symbol; X as the second symbol;
X as the third symbol.
ROS has no ITU designator marking it as spread spectrum.
Furthermore, from part 97.307 places this limitation on any
data mode transmitted in the HF bands:
(2) No non-phone emission shall exceed the bandwidth of a
communications quality phone emission of the same
modulation type. The total bandwidth of an independent
sideband emission (having B as the first symbol), or a
multiplexed image and phone emission, shall not exceed
that of a communications quality A3E emission.
ROS follows this rule.
In short, ROS has not been ruled to be a spread spectrum mode
by the FCC or the ITU, and fits within the bandwidth of a phone
communications signal on HF.
It also follows the common sense rule of not causing any harm
on the HF bands. It really is not much different from the
other data modulations out there. JT65, Throb and RTTY also
have empty space between carrier positions.
I would certainly try out ROS, if it weren't for the fact that
I don't have a Windows PC and ROS does not seem to run anywhere
else...
--
All rights reversed.
