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T1D03

COMMISSION'S RULES · Authorized and prohibited transmissions; Sale of equipment

T1D03§ 97.211(b), 97.215(b), 97.113(a)(4)T1D →

When is it permissible to transmit messages encoded to obscure their meaning?

  1. AOnly when using a remote station during a contest
  2. BOnly when transmitting certain approved digital codes
  3. COnly when transmitting control commands to space stations or model craft
  4. DNever
Why Section 97.113(a)(4) bans transmissions with codes or ciphers intended to obscure their meaning, because amateur communications must be open to monitoring. Two narrow exceptions exist: 97.211(b) permits obscured telecommand signals sent to control a space station, and 97.215(b) permits them for radio control of model craft. In both cases the encoding protects the craft from hijacking, not the content of a conversation.
Watch out The choice that says never is close to the general rule but misses the two telecommand exceptions the pool question is specifically testing; digital modes like RTTY, PSK31 or FT8 are fine because their codes are published, not secret.
Obscured codes are only for commanding things you control: satellites and model craft.
HamSandwich explanation, first draft. The question and answers are the NCVEC text.
47 CFR 97.211(b) Space telecommand station.

(a) Any amateur station designated by the licensee of a space station is eligible to transmit as a telecommand station for that space station, subject to the privileges of the class of operator license held by the control operator.

(b) A telecommand station may transmit special codes intended to obscure the meaning of telecommand messages to the station in space operation.

(c) The following frequency bands and segments are authorized to telecommand stations:

(1) The 17 m, 15 m, 12 m and 10 m bands, 6 mm, 4 mm, 2 mm and 1 mm bands; and

(2) The 7.0-7.1 MHz, 14.00-14.25 MHz, 144-146 MHz, 435-438 MHz, 1260-1270 MHz and 2400-2450 MHz, 5.65-5.67 GHz, 10.45-10.50 GHz and 24.00-24.05 GHz segments.

(d) A telecommand station may transmit one-way communications.

eCFR text as of 1 Sep 2026 · read on ecfr.gov
47 CFR 97.215(b) Telecommand of model craft.

An amateur station transmitting signals to control a model craft may be operated as follows:

(a) The station identification procedure is not required for transmissions directed only to the model craft, provided that a label indicating the station call sign and the station licensee's name and address is affixed to the station transmitter.

(b) The control signals are not considered codes or ciphers intended to obscure the meaning of the communication.

(c) The transmitter power must not exceed 1 W.

eCFR text as of 1 Sep 2026 · read on ecfr.gov
47 CFR 97.113(a)(4) Prohibited transmissions.

(a) No amateur station shall transmit:

(1) Communications specifically prohibited elsewhere in this part;

(2) Communications for hire or for material compensation, direct or indirect, paid or promised, except as otherwise provided in these rules;

(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.

(4) Music using a phone emission except as specifically provided elsewhere in this section; communications intended to facilitate a criminal act; messages encoded for the purpose of obscuring their meaning, except as otherwise provided herein; obscene or indecent words or language; or false or deceptive messages, signals or identification.

(5) Communications, on a regular basis, which could reasonably be furnished alternatively through other radio services.

(b) An amateur station shall not engage in any form of broadcasting, nor may an amateur station transmit one-way communications except as specifically provided in these rules; nor shall an amateur station engage in any activity related to program production or news gathering for broadcasting purposes, except that communications directly related to the immediate safety of human life or the protection of property may be provided by amateur stations to broadcasters for dissemination to the public where no other means of communication is reasonably available before or at the time of the event.

(c) No station shall retransmit programs or signals emanating from any type of radio station other than an amateur station, except propagation and weather forecast information intended for use by the general public and originated from United States Government stations, and communications, including incidental music, originating on United States Government frequencies between a manned spacecraft and its associated Earth stations. Prior approval for manned spacecraft communications retransmissions must be obtained from the National Aeronautics and Space Administration. Such retransmissions must be for the exclusive use of amateur radio operators. Propagation, weather forecasts, and manned spacecraft communications retransmissions may not be conducted on a regular basis, but only occasionally, as an incident of normal amateur radio communications.

(d) No amateur station, except an auxiliary, repeater, or space station, may automatically retransmit the radio signals of other amateur station.

eCFR text as of 1 Sep 2026 · read on ecfr.gov
← T1D02 All of T1D T1D04 →

The rest of T1D

  1. T1D01 With which countries are FCC-licensed amateur radio stations prohibited from exchanging communications?
  2. T1D02 Under which of the following circumstances are one-way transmissions by an amateur station prohibited?
  3. T1D03 When is it permissible to transmit messages encoded to obscure their meaning?
  4. T1D04 Under what conditions is an amateur station authorized to transmit music using a phone emission?
  5. T1D05 When may amateur radio operators use their stations to notify other amateurs of the availability of equipment…
  6. T1D06 What, if any, are the restrictions concerning transmission of language that may be considered indecent or obs…
  7. T1D07 Which of the following is an example of an auxiliary station?
  8. T1D08 In which of the following circumstances may the control operator of an amateur station receive compensation f…
  9. T1D09 When may amateur stations transmit information in support of broadcasting, program production, or news gather…
  10. T1D10 How does the FCC define broadcasting for the Amateur Radio Service?
  11. T1D11 When may an amateur station transmit without identifying on the air?
  12. T1D12 Which of the following is required when making on-the-air test transmissions?
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