2020 Extra Class study guide: E1D – Amateur space and Earth stations; telemetry and telecommand rules; identification of balloon transmissions; one-way communications

One of the cool things that amateur radio operators can do is to use satellites to communication with one anther. In the amateur satellite service, the satellites are called space stations and are remotely controlled by telecommands. Space stations can transmit on the 40m, 20m, 17m, 15m, 12m and 10m HF bands, the 2 meter VHF band, and the 70 cm and 13 cm UHF bands.

QUESTION: Which HF amateur bands have frequencies authorized for space stations? (E1D07)
ANSWER: Only the 40, 20, 17, 15, 12, and 10 meter bands

QUESTION: Which VHF amateur bands have frequencies authorized for space stations? (E1D08)
ANSWER: 2 meters

QUESTION: Which UHF amateur bands have frequencies authorized for space stations? (E1D09)
ANSWER: 70 cm and 13 cm

Space stations are controlled by telecommand stations, which are amateur stations that transmits communications to initiate, modify or terminate functions of a space station. Any amateur station designated by the space station licensee is eligible to be a telecommand station, assuming that the station’s control operator has the appropriate privileges. In order to prevent malicious telecommands being sent to a space station, space telecommand stations may transmits special codes intended to obscure the meaning of a message. The only time amateur radio operators are allowed to use this type of encryption is when sending telecommands to a space station or a radio-controlled mode.

QUESTION: What is a space telecommand station? (E1D03)
ANSWER: An amateur station that transmits communications to initiate, modify or terminate functions of a space station

QUESTION: Which amateur stations are eligible to be telecommand stations of space stations (subject to the privileges of the class of operator license held by the control operator of the station)? (E1D10)
ANSWER: Any amateur station so designated by the space station licensee

QUESTION: Which of the following may transmit special codes intended to obscure the meaning of messages? (E1D02)
ANSWER: Telecommand signals from a space telecommand station

To obtain information about the operation of a space station or a high-altitude balloon, the space station or balloon might send telemetry. Telemetry is the one-way transmission of measurements at a distance from the measuring instrument. For example, a space station might use telemetry to send information such as ambient temperature and battery status. In addition to the measurement information, the station sending telemetry must also identify with their call sign.

QUESTION: What is the definition of telemetry? (E1D01)
ANSWER: One-way transmission of measurements at a distance from the measuring instrument

QUESTION: Which of the following is required in the identification transmissions from a balloon-borne telemetry station? (E1D04)
ANSWER: Call sign

Telemetry is an example of a one-way communication, and one of very few cases in which amateur radio stations my transmit one-way communications. Space stations, beacon stations, and telecommand stations can all transmit one-way communications.

QUESTION: Which of the following amateur stations may transmit one-way communications? (E1D12)
ANSWER: A space station, beacon station, or telecommand station

Space stations operate at an altitude of 50 km or higher. Stations that operate below that altitude are called Earth stations. Any amateur station whose control operator has the appropriate privileges can operate as an Earth station,

QUESTION: Which amateur stations are eligible to operate as Earth stations? (E1D11)
ANSWER: Any amateur station, subject to the privileges of the class of operator license held by the control operator

Radio-controlled models

Amateur radio operators can use amateur radio frequencies to control model crafts. Instead of identify on the air, a photocopy of the station license, a label with the name, address, and telephone number of the station licensee, and a label with the name, address, and telephone number of the control operator must be posted at the telecommand station location. A transmitter sending telecommands is limited to only 1 watt of output power.

QUESTION: What must be posted at the station location of a station being operated by telecommand on or within 50 km of the earth’s surface? (E1D05)
ANSWER: All these choices are correct

• • A photocopy of the station license
  • A label with the name, address, and telephone number of the station licensee
  • A label with the name, address, and telephone number of the control operator

QUESTION: What is the maximum permitted transmitter output power when operating a model craft by telecommand? (E1D06)
ANSWER: 1 watt