ROS and CHIP deemed illegal below 222 mHz for U.S. amateurs

Careful now, you might get everyone to write the FCC for permission to use CW... They might raise their hands for permission to go to the bathroom.

 

There is no specific authorization in Part 97 to use the bathroom. Is it also SS?

Personally, I think this all boils down to an error in translation by the author. Being bi-lingual, I can see where the author came up with his FHSS while not realizing the technical meaning of the phrase. Moral of this story is mean what you write down.

AG4CZ -John

 

I think I just left a spurious emission.

 

No, it's SR (Spread Rectum)

 

1. With all due respect (and tongue in cheek) the gent who asked the FCC for a ruling should be soundly thrashed about the head and shoulders with a rolled up newspaper!

2. "Never ask a question you don't want to know the answer to". Now we are jammed and can't use the mode on HF.

3. Nevertheless, I see that the matter is still open for interpretation, seeing as the FCC stated that they did NOT review the technical aspects of the mode, and left it up to the designers statement/judgement. Therefore, the FCC should be equally open to accept Other amateurs judgement who have equal or better education and experience to the designer that the mode is not spread spectrum.

4. As described so far, this mode is NOT SS. The description makes no mention of shifting the center frequency, retuning the radio etc. It uses no more bandwidth that the majority of ham modes in use today.

5. To the scopes men, the scopes!

 

Since I didn't see it posted previously, some links:

ROS site:
http://rosmodem.wordpress.com/

Southgate newsletter comment:
http://www.southgatearc.org/news/february2010/ros_proving_popular.htm

 

I am always intrigued by the minions of QRZ and the FCC. If you read the FCC "determination", it is clear to see that it is not a determination, but rather an affirmation of whatever the author says. If the person says a certain mode is SS, then it can't be used because the FCC assumes that the author knows what he is talking about.

So, the author just needs to reword his description, and it will become legal, at least as far as the FCC is concerned. If it is illegal, then the control op is responsible. I don't see where the FCC has determined that it is illegal, or that it is even SS.

The description doesn't seem to fit SS, regardless of what the author claims, or understands. Some "do gooder" ham has glommed onto a word or phrase and made an arbitrary determination based on bad info.

Joe

 

According to Agent 3820 (don't you just love anonymous government employee's), the station operator has to make the judgement of whether their station is compliant.

I hope he isn't too highly paid...

 

FCC Rules for Digital Data Emissions

Let's not rule out 97.309: RTTY and data emission code.

(4) An Amateur Station transmitting RTTY OR data emission using a digital code specified in this paragraph may use ANY TECHNIQUE WHOSE TECHNICAL CHARACTERISTICS HAVE BEEN DOCUMENTED PUBLICLY, such as CLOVER, G-TOR, or PacTOR, for the purpose of facilitating communications.
[Easy-Pal, CHIP64, PSK, MT63, etc...]

Spread Spectrum:

(c) Only the following types of SS emission transmissions are authorized (hybrid SS emissions transmissions involving both spreading techniques are prohibited):

(1) Frequency hopping where the carrier of the transmitted signal is modulated with un-ciphered information and CHANGES FREQUENCY at fixed intervals under the direction of a high speed code sequence.

(2) Direct sequence where the information is modulo-2 added to a high speed code sequence. The combined information and code are then used to modulate the RF carrier. The high speed code sequence dominates the modulation function, and is the direct cause of the WIDE SPREADING of the transmitted signal.

The Spread Spectrum mentioned in the FCC RULES Part 97 is clear, Frequency Hopping and Direct Sequencing for Wide Spreading.

Audio Spread Spectrum DOES NOT fit the bill as SS as defined in the FCC Rules; the mode specifics are documented publicly and decipherable by anyone and occupy the specified bandwidth for the Emission Type: SSB; without Frequency hopping and/or Wide Spreading.


Rich Davis W4NMH-Extra

ARRL Life Member
ARRL Volunteer Examiner
ARRL Instructor

 

Let's not rule out 97.309: RTTY and data emission code.

 

From what the author has written, it seems that 144 is the number of symbols in a frame (16 preamble symbols followed by 128 data symbols). That is not 144FSK. MFSK uses 1 of M orthogonal tones to encode a symbol. One symbol is sent during each signaling period.

One cannot encode 11 bits of data using 144FSK, as log2(144) ~= 7.17 bits (i.e., M should be a power of two). What one can do with 144 orthogonal tones is to use two frequency centers and send one 128FSK data symbol in parallel with one 16FSK control symbol each signaling period (i.e., 2^7 + 2^4 < 2^11, where the symbol "^" denotes raised to the power of). Why anyone would complicate things by using out-of-band control signaling is beyond me. Something is clearly getting lost in the translation between the author's native language and English, as I do not believe that he is using this approach.

 

For 1 baud, 2 or 3 kHz bandwidth is wide relative to narrow emissions that convey an order of magnitude more data using an order of mangitude less bandwidth. I think technically you have spread spectrum when the bandwidth used exceeds the minimum bandwidth needed to convey the same amount of intelligence by at least 10x.
A ROS transmission seems like a relatively wide code compared with it's bandwidth cousin, SSB voice, one of ham radio's more information-rich signals.

What puzzles me is how so many operators are willing to allow untested software control their radio stations. What's up with that?

 

Rich, you reference part 97.309 out of context, a common source of confusion regarding permitted codes versus permitted emissions.
Paragraph (4) is subordinate to subsection (a), which contains the caveat that the emission is subject to 97.305(c) and 97.307(f) before the subordinate allowances for the various codes can be considered.

You also reference some rules (c)(1)&(2), which are actually from a previously enforced version of 97.311 "SS", repealed/amended in 1999, and shouldn't be confused with 97.309 permitted codes. If I use audio frequency to modulate an AM carrier, I can affect a frequency hopping of the sideband, or as my friend put it the other day: digital radios are still analog radios.

The FCC was ordered to amend the rules in 1999 as follows:
§ 97.311 SS emission types.
(a) SS emission transmissions by an amateur station are authorized only for communications
between points within areas where the amateur service is regulated by the FCC and between an area
where the amateur service is regulated by the FCC and an amateur station in another country that permits
such communications. SS emission transmissions must not be used for the purpose of obscuring the
meaning of any communication.
(b) A station transmitting SS emissions must not cause harmful interference to stations
employing other authorized emissions, and must accept all interference caused by stations employing
other authorized emissions.
(c) When deemed necessary by a District Director to assure compliance with this Part, a station
licensee must:
(1) Cease SS emission transmissions;
(2) Restrict SS emission transmissions to the extent instructed; and
(3) Maintain a record, convertible to the original information (voice, text, image, etc.) of
all spread spectrum communications transmitted.
(d) The transmitter power must not exceed 100 W under any circumstances. If more than 1 W is
used, automatic transmitter control shall limit output power to that which is required for the
communication. This shall be determined by the use of the ratio, measured at the receiver, of the received
energy per user data bit (Eb) to the sum of the received power spectral densities of noise (N0) and cochannel
interference (I0). Average transmitter power over 1 W shall be automatically adjusted to maintain
an Eb/ (N0 + I0) ratio of no more than 23 dB at the intended receiver.

 

The FCC regulatory definition in Part 97.3 only says this:

Basically the only germane question is does the mode fit that description, or doesn't it, regardless of what the creator might have called it? The FCC response to the inquiry only states that they assumed it was SS based on the creator's description. They did not make an actual technical determination.

 

So you're saying that those people who developed SSB, RTTY, and PSK-31 (for example) should have never allowed the untested software to control their radio station?

Experimentation, not emergency management, is what Amateur Radio is all about. If you kill experimenters, you kill Ham radio.