IMO, ROS is not *true* SS in the legal sense. Other posts I've read cite an FCC reference that SS involves spreading the signal EVENLY over the bandwidth. ROS is using 16 DISCRETE tones to modulate, with a lot more empty space than actual signal. I'm curious how much of spread spectrum's jam resistance is created by ROS.
I plan to try ROS as soon as a new version is released which will allow me to utilize a non-default sound card. I've run the currently available version, but the sound came out over my PC speakers rather than going into my interface, so I never transmitted anything. FCC rules, IMHO, include several gray areas. For example, is it permissable to send a PGP-signed message over the airwaves? The message itself is plain text, but it includes a cryptographic SIGNATURE for authentication purposes. According to the spirit of the law, that should be a Good Thing <tm> since it actually discourages the sending of false signals. Technically, though, there are a few bytes of "code and cypher" attached. We won't even discuss steganography, where a secret message is embedded in a harmless-appearing file, such as a .JPG file. Perhaps we need a ROS specific group to discuss this mode? -- Dave - AF6AS ----- Original Message ----- From: "vinceinwaukesha" <vi...@mulhollon.com> To: <digitalradio@yahoogroups.com> Sent: Friday, February 19, 2010 2:51 PM Subject: [digitalradio] Re: ROS, legal in USA? > --- In digitalradio@yahoogroups.com, Dave Ackrill <dave.g0...@...> wrote: >> >> Does anyone have a definition of real spread spectrum? As I hate to >> think what will happen when/if people with even less knowledge than I >> have of what 'real' spread spectrum is get the idea that RIO is >> something that it is actually not and start their inevitable campaign of >> 'It's illegal, it's immoral and it makes you fat', to use the words of >> the song... >> >> Dave (G0DJA) >> > > Well, as a G0 its perfectly acceptable that you don't know. The K's N's > W's and A's have no such excuse. > > Lets check out 47CFR2.201 and see what type of signal ROS is. > > The first letter is modulation. Clearly its F Frequency modulated. I > read the ROS PDF and its basically a 16FSK that has its carrier frequency > modulated/wiggled in a peculiar pattern. > > The number is "nature of signal(s) modulating the main carrier". Clearly > its 2, "A single channel containing quantized or digital information with > the use of a modulating sub-carrier, excluding time-division multiplex". > That sub-carrier is the 16FSK, which thankfully (?) isn't TDM data. > > The second letter is "type of information to be transmitted". Well, > obviously that is D for data. We're not sending "E" voice or "A" > telegraph or whatever here. > > So, the overall "FCC Emission designator" would pretty obviously be "F2D". > > Where can we run F2D? First, hit FCC 97.305(c) "authorized emission > types" table. The FCC says SS only on 222 and up. I have no idea what > inspires people to publically claim you can only run SS on 432 and up, as > 97.305(c) explicitly permits it on 222 and up. For another example, on > 30M we can do RTTY or DATA. > > How does "DATA" or "RTTY" or "SS" or "PULSE" relate to emissions > designators? The FCC helpfully defines that in 97.3(c) > > To qualify as SS all it needs per 97.3(c)(8) is "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." > > F2D doesn't seem to match the def of "SS". > > To qualify as DATA all it needs per 97.3(c)(2) is "Telemetry, telecommand > and computer communications emissions having (i) designators with A, C, D, > F, G, H, J or R as the first symbol, 1 as the second symbol, and D as the > third symbol; (ii) emission J2D; and (iii) emissions A1C, F1C, F2C, J2C, > and J3C having an occupied bandwidth of 500 Hz or less when transmitted on > an amateur service frequency below 30 MHz. Only a digital code of a type > specifically authorized in this part may be transmitted." > > F2D doesn't seem to match the def of "DATA". > > Looks like USA folks can't transmit ROS at all, on any band. Ooops. > > Will people fooling around with ROS get dragged to court? Probably not. > See 97.305(b) "A station may transmit a test emission on any frequency > authorized to the control operator for brief periods for experimental > purposes, except that ... (essentially no SS or pulse where not otherwise > permitted)". So, fooling around for testing and experimentation of a new > mode is well within the law by this exception. Running a contest, a > regular schedule, a formal net, DXing, QSL card collecting, county > hunting, or extensive ragchewing would be strictly verboten under > 97.305(b). The key is doing it in a documented manner as an experiment, > like as a research experiment or an article for QEX. Realize that big > brother can deprive you of your life and liberty at any time for any > reason, its not as if a rule prevents that, it just claims Big Bro won't > do it, and politicians never lie... > > In summary, the problem seems to be FM modulating the carrier of the > 16FSK. > > 73 de Vince N9NFB
