2014 Tech study guide: digital modes

Three questions in this section were updated. The answer to TD802 was changed from “Automatic Position Reporting System” to “Automatic Packet Reporting System.” T8D05 was changed from a kind of irrelevant question about Techs being able to use data in the 219 to 220 MHz range to one about an application of APRS. T8D11 was changed from a question about the parity bit to one about ARQ transmission….Dan

When hams talk about “digital modes,” we are talking about the ways in which we use a computer in conjunction with a radio to communicate with one another. They all involve sending digital data back and forth to one another. All of these choices are correct (examples of a digital communications method) (T8D01):

  • Packet
  • PSK31
  • MFSK

Packet radio was one of the first digital modes. It is called packet radio because the data to be sent from station to station is separated into a number of packets which are then sent separately by the transmitting station and received and re-assembled by the receiving station. All of these choices are correct when talking about what may be included in a packet transmission (T8D08):

  • A check sum which permits error detection
  • A header which contains the call sign of the station to which the information is being sent
  • Automatic repeat request in case of error

Some amateur radio digital communications systems use  protocols which ensure error-free communications. One such system is called an automatic repeat request, or ARQ, transmission system. An ARQ transmission system is a digital scheme whereby the receiving station detects errors and sends a request to the sending station to retransmit the information. (T8D11)

APRS is one service that uses packet radio. The term APRS means Automatic Packet Reporting System. (T8D02) A Global Positioning System receiver is normally used when sending automatic location reports via amateur radio. (T8D03) Providing real time tactical digital communications in conjunction with a map showing the locations of stations is an application of APRS (Automatic Packet Reporting System). (T8D05)

A popular digital mode on the HF bands is PSK. The abbreviation PSK means Phase Shift Keying. (T8D06) PSK31 is a low-rate data transmission mode. (T8D07)

Comments

  1. So is it:
    APRS means Automatic Position Reporting System. (T8D02)

    or:
    APRS (Automatic Packet Reporting System). (T8D05)

  2. Larry Koziel says:

    According to Bob Bruninga WB4APR, the father and namesake of APRS, the acronym stands for “Automatic Packet Reporting System.” See http://www.aprs.org/ or http://en.wikipedia.org/wiki/Automatic_Packet_Reporting_System.

    Reporting position was one of the first applications, but Bob constantly points out that it’s not restricted just to reporting position.

    Larry K8MU

  3. Dan KB6NU says:

    Great catch!

    In the 2010 question pool the answer to TD802 was “Automatic Position Reporting System.” In the new question pool, they changed it to “Automatic Packet Reporting System.” I’ve made the appropriate changes to the text above.

Speak Your Mind

*