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E1D02

COMMISSION RULES · Amateur Space and Earth stations; telemetry and telecommand rules; identification of balloon transmissions; one-way communications

E1D02§ 97.211(b)E1D →

Which of the following may transmit encrypted messages?

  1. ATelecommand signals to terrestrial repeaters
  2. BTelecommand signals from a space telecommand station
  3. CAuxiliary relay links carrying repeater audio
  4. DMesh network backbone nodes
Why Section 97.113(a)(4) bans messages encoded to obscure their meaning, but Part 97 carves out a specific exception in 97.211(b): a space telecommand station may transmit special codes intended to obscure the meaning of telecommand messages to a space station. The reason is security - without it, anyone could seize control of a satellite and command it off, reorient it, or dump its memory. The same logic gives radio control of model craft a similar narrow exception.
Watch out Telecommand of terrestrial repeaters travels over auxiliary or control links that enjoy no encryption exception, so those control tones and any mesh or relay traffic must remain in the clear.
Encryption is legal only where you cannot reach the hardware: satellites (and model craft). Everything on the ground stays in the clear.
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
← E1D01 All of E1D E1D03 →

The rest of E1D

  1. E1D01 What is the definition of telemetry?
  2. E1D02 Which of the following may transmit encrypted messages?
  3. E1D03 What is a space telecommand station?
  4. E1D04 Which of the following is required in the identification transmissions from a balloon-borne telemetry station?
  5. E1D05 What must be posted at the location of a station being operated by telecommand on or within 50 kilometers of …
  6. E1D06 What is the maximum permitted transmitter output power when operating a model craft by telecommand?
  7. E1D07 Which of the following HF amateur bands include allocations for space stations?
  8. E1D08 Which VHF amateur bands have frequencies authorized for space stations?
  9. E1D09 Which UHF amateur bands have frequencies authorized for space stations?
  10. E1D10 Which amateur stations are eligible to be telecommand stations of space stations, subject to the privileges o…
  11. E1D11 Which amateur stations are eligible to operate as Earth stations?
  12. E1D12 Which of the following amateur stations may transmit one-way communications?
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