Spurious is defined as "Not being what it purports to be; false or fake."

Spurious emissions are "false" emissions that accompany legitimate emissions. Usually they are caused by a poorly calibrated or faulty transmitter. On a spectrum analyzer they would show up as being spikes of RF energy sometimes adjacent to the real signal and sometimes at random intervals usually close by.

These emissions are "spurious" or "false" because they are not necessary to receive the information and they are outside the normal bandwidth needed for the signal.

Tip: The correct answer is the only one that contains the word "emission" from the question.

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Environmental or historical significance may limit land use in some cases and this includes where someone can install an antenna so the FCC regulates the physical location where the antenna can be built.

Don't let the word horticultural trip you up!

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§ 97.13 Restrictions on station location.

(b) A station within 1600 m (1 mile) of an FCC monitoring facility must protect that facility from harmful interference. Failure to do so could result in imposition of operating restrictions upon the amateur station by a District Director pursuant to § 97.121 of this part. Geographical coordinates of the facilities that require protection are listed in § 0.121(c) of this chapter.

TEST TIP: These monitoring stations tend to be little shacks with antenna arrays out in an empty field set away from likely sources of interference (see https://goo.gl/maps/msXm2pqVgJSAPeCj6).

With that visual in mind, you can think to yourself "there should be no interference within a COUNTRY MILE (1 mile) of the FCC shack."

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You only need to work with the FCC. Go to their website www.fcc.gov and search for "Environmental Assessment" and the forms will be listed.

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Title 47 CFR Part 97 § 97.3(a)(33)

(33) National Radio Quiet Zone. The area in Maryland, Virginia and West Virginia Bounded by 39°15′ N on the north, 78°30′ W on the east, 37°30′ N on the south and 80°30′ W on the west.

Reference:

https://www.ecfr.gov/current/title-47/chapter-I/subchapter-D/part-97#p-97.3(a)(33)

From Wikipedia:

The National Radio Quiet Zone (NRQZ) is a large area of land in the United States designated as a radio quiet zone, in which radio transmissions are restricted by law to facilitate scientific research and the gathering of military intelligence. About half of the zone is located in the Blue Ridge Mountains of west-central Virginia while the other half is in the Allegheny Mountains of east-central West Virginia; a small part of the zone is in the southernmost tip of the Maryland panhandle.

http://en.wikipedia.org/wiki/United_States_National_Radio_Quiet_Zone

TEST TIP: "OBSERVE the Quiet Zone at all hours."

Memory trick: both the question and answer contain National Radio

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This is an overlapping jurisdiction question. The FAA regulates Airspace that might endanger aircraft so their regulations need to be consulted and it will then need to registered with the FCC as required by part 17.

Hint: The question deals with Aviation and Amateur Radio. The correct answer references both the FAA and FCC.

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Any modulation index greater than 1.0 will result in bandwidths that are wider than necessary for good amateur practices.

§ 97.307 Emission standards. (a) No amateur station transmission shall occupy more bandwidth than necessary for the information rate and emission type being transmitted, in accordance with good amateur practice. (b) Emissions resulting from modulation must be confined to the band or segment available to the control operator. Emissions outside the necessary bandwidth must not cause splatter or keyclick interference to operations on adjacent frequencies.

The definition of modulation index differs between AM and FM.

The AM Modulation Index is (\(m = \frac{M}{A}\)), where M = the peak CHANGE in modulated carrier AMPLITUDE from its UNMODULATED value, and A = the unmodulated carrier amplitude. A modulation index of 1 is when the envelope cycles between TWICE the steady state value (increases by 1X) and ZERO (decreases by 1X) .

With FM, the FM carrier FREQUENCY is modulated by some frequency spectrum, typically speech. The FM modulation index is (\(m = \frac{Fd}{A}\)), where Fd is the maximum deviation from the carrier frequency, and A is the highest audio frequency.

If the maximum deviation Fd of a signal, set by FCC standards at down 26 dB, is, say, 3 kHz on either side of the center freq (146.52 MHz, for example), and the modulating frequency A is speech low-pass filtered to 3 kHz, then the modulation index is (\(\frac{3000}{3000} = 1\)), right at the limit. If the transmitted signal had side bands that used, say, 5 kHz on either side of the carrier frequency, for the same 3 kHz audio stream, the MI would be (\(\frac{5000}{3000} = 1.67\)).

ARRL 2021 Handbook, Sect 11.3 Angle Modulation

SILLY HINT: 29 MHz is the 10 Metre band, answer is 1.0 (10)

For further reading: Wikipedia on modulation indexes

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The FCC may impose limited quiet periods on the amateur station on those frequencies involved. Conversely, the amateur station must be operating properly without violating any rules especially regarding spurious emissions.

Hint: Long question, long answer.

Silly hint: Correct answer does not include the phrase "must cease".

Hint: The question and answer both include the word “interference”

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You must first register with the local civil defense organization and then at that point you can register your amateur radio station with RACES. Each operator must follow the operator privileges granted by the license.

§ 97.407 Radio amateur civil emergency service.

(a) No station may transmit in RACES unless it is an FCC-licensed primary, club, or military recreation station and it is certified by a civil defense organization as registered with that organization, or it is an FCC-licensed RACES station. No person may be the control operator of a RACES station, or may be the control operator of an amateur station transmitting in RACES unless that person holds a FCC issued amateur operator license and is certified by a civil defense organization as enrolled in that organization.

Hint: Civil defense

Silly Hint: You have to be Responsible for RACES

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The frequencies that may be used are determined by the control operator's license. Normally RACES stations will communicate with other RACES stations but other stations may be authorized by a responsible civil defense authority.

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§ 97.307 Emission standards.

For transmitters installed after January 1, 2003, the mean power of any spurious emission from a station transmitter or external RF power amplifier transmitting on a frequency below 30 MHz must be at least 43 dB below the mean power of the fundamental emission.

Memory tips:

• The “f” in fundamental and “e” in emission, together… forty-three (43).
• The lowest number in the list
• date of 1/1/2003 think 1+1+2=4, 3 or 43
• "86'd" is a slang term meaning "to get rid of." The correct answer (43 dB) is half way to 86. FCC doesn't expect us to completely eliminate spurious emissions, so just think of the expectation as being "half way to 86'd".

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