Spread spectrum (SS) uses a wide bandwidth which would cause too much crowding on the relatively narrow bands below UHF.
See FCC rules: §97.305 Authorized emission types.
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Older equipment that was produced prior to new regulations and can be used in a legal manner are allowed to be sold by hams. This is how working but older equipment is effectively grandfathered in to current use. Of course good amateur radio practices should be always followed. The below 144 MHz prohibition was a result of unlawful citizen band overpowering.
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Silly memory trick: Canadians are known for saying, “Eh?” So think of the question as, “Line, eh?” 🙂
Private land mobile radio services, 47 C.F.R. § 90.7 (2010):
Line A. An imaginary line within the U.S., approximately paralleling the U.S.-Canadian border, north of which Commission coordination with the Canadian authorities in the assignment of frequencies is generally required. It begins at Aberdeen, Washington, running by great circle arc to the intersection of 48° N., 120° W., then along parallel 48° N., to the intersection of 95° W., thence by great circle arc through the southernmost point of Duluth, Minnesota, thence by great circle arc to 45° N., 85° W., thence southward along meridian 85° W. to its intersection with parallel 41° N., to its intersection with meridian 82° W., thence by great circle arc through the southernmost point of Bangor, Maine, thence by great circle arc through the southernmost of Searsport, Maine, at which point it terminates.
Private land mobile radio services, 47 C.F.R. § 97.3 (2010):
- Line A. Begins at Aberdeen, WA, running by great circle arc to the intersection of 48° N, 120° W, thence along parallel 48° N, to the intersection of 95° W, thence by great circle arc through the southernmost point of Duluth, MN, thence by great circle arc to 45° N, 85° W, thence southward along meridian 85° W, to its intersection with parallel 41° N, thence along parallel 41° N, to its intersection with meridian 82° W, thence by great circle arc through the southernmost point of Bangor, ME, thence by great circle arc through the southernmost point of Searsport, ME, at which point it terminates.
page 244, 589
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Line A roughly parallels the border between the Lower 48 States and Canada, about one degree south of the border. Line B is the Canadian counterpart, running about one degree north of the border.
Check out the following for more information: Private land mobile radio services, 47 C.F.R. § 97.303 (2010):
(m) In the 70 cm band:
(1) No amateur station shall transmit from north of Line A in the 420-430 MHz segment. See §97.3(a) for the definition of Line A.
pages 244 and 609
Memory aid: "Stay away from 420 when you're up high." (I know, groan, but you don't forget it.)
Another memory aid: Only those below the line can use the lower end of the 70cm band
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§97.113 Prohibited transmissions.
(a) No amateur station shall transmit:
(3) Communications in which the station licensee or control operator has a pecuniary interest, including communications on behalf of an employer, with the following exceptions:
(i) A station licensee or station control operator may participate on behalf of an employer in an emergency preparedness or disaster readiness test or drill, limited to the duration and scope of such test or drill, and operational testing immediately prior to such test or drill. Tests or drills that are not government-sponsored are limited to a total time of one hour per week; except that no more than twice in any calendar year, they may be conducted for a period not to exceed 72 hours.
(ii) An amateur operator may notify other amateur operators of the availability for sale or trade of apparatus normally used in an amateur station, provided that such activity is not conducted on a regular basis.
(iii) A control operator may accept compensation as an incident of a teaching position during periods of time when an amateur station is used by that teacher as a part of classroom instruction at an educational institution.
(iv) The control operator of a club station may accept compensation for the periods of time when the station is transmitting telegraphy practice or information bulletins, provided that the station transmits such telegraphy practice and bulletins for at least 40 hours per week; schedules operations on at least six amateur service MF and HF bands using reasonable measures to maximize coverage; where the schedule of normal operating times and frequencies is published at least 30 days in advance of the actual transmissions; and where the control operator does not accept any direct or indirect compensation for any other service as a control operator.
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The answer is:
Communications transmitted for hire or material compensation, except as otherwise provided in the rules
All the other listed types of communications are permitted.
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Spread spectrum is authorized, but with explicit limitations similar to regulations covering the rest of the amateur service.
It cannot cause harmful interference to other stations. It can slightly raise noise floor as long as it doesn't disrupt communications.
The FCC's authorization of spread spectrum for amateurs only applies in areas where the FCC has jurisdiction. If you are using reciprocal operating rights in another country, the other country must have permitted spread spectrum and you must comply with that country's rules.
Spread spectrum often uses pseudo-random sequences to define channel hopping or to blend with the modulating signal to spread the sequence out. This spreading cannot be used to obscure signals or as a code to prevent the meaning from being evident (generally, amateurs will use a published pseudo-random sequence to comply).
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03/04/2011 -- In a Report and Order adopted February 22 and released March 4, 2011, the Federal Communications Commission has eliminated the requirement that amateur stations transmitting Spread Spectrum use Automatic Power Control (APC) to reduce transmitter power. At the same time, the Commission has reduced the maximum power of a Spread Spectrum emission from 100 to 10 W PEP.
The R&O explains the Commission’s actions this way: “We believe that these rules changes will (1) encourage individuals who can contribute to the advancement of the radio art to more fully utilize SS technologies in experimentation, and (2) balance the interests of all users in mixed-mode and mixed-service frequency bands until sharing protocols are sufficiently developed to avoid interference.”
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5 watts to produce full legal output is not correct. The FCC actually maintains a limit of 15dB gain on HF amplifiers as a way of regulating the misuse of Amateur amplifiers which are repurposed for CB. So 5W could only legally be amplified to around ~150W.
External switching really has nothing to do with the question or with amplifier standards.
A gain of 0 is no amplification at all and the question is about amplifiers.
"Satisfying the FCCs spurious emission standards" is correct because the FCC is always concerned with keeping the bands clean and high power amps always create a certain amount of noise (spurious emissions). That is why the FCC publishes spurious emission standards.
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All amateurs, except Novices, may put auxiliary stations on the air [97.201(a)].
Note: Since the FCC no longer issues licenses for Novice and Advanced, you might be tempted to select "Any licensed amateur operator" However, there are still individuals who hold Novice and Advanced licenses (the FCC has not forced them to upgrade.), And those who have Novice licenses are not allowed to handle auxiliary stations.
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