Amateur Extra E2D: VHF digital modes and APRS
These are the 11 official questions in group E2D of the 2024–2028 Amateur Extra question pool, with the correct answer marked and a plain-English explanation of why it's right. The real exam asks one question from this group.
- E2D01Question 1
Which of the following digital modes is designed for meteor scatter communications?
- AWSPR
- BMSK144 Correct
- CHellschreiber
- DAPRS
Why: MSK144 is designed for meteor scatter.
- E2D02Question 2
What information replaces signal-to-noise ratio when using the FT8 or FT4 modes in a VHF contest?
- ARST report
- BState abbreviation
- CSerial number
- DGrid square Correct
Why: In VHF contests, FT8 and FT4 send grid squares instead of signal-to-noise reports.
- E2D03Question 3
Which of the following digital modes is designed for EME communications?
- AMSK144
- BPACTOR III
- CWSPR
- DQ65 Correct
Why: Q65 is designed for EME.
- E2D04Question 4
What technology is used for real-time tracking of balloons carrying amateur radio transmitters?
- AFT8
- BBandwidth compressed LORAN
- CAPRS Correct
- DPACTOR III
Why: APRS tracks balloons in real time.
- E2D05Question 5
What is the characteristic of the JT65 mode?
- AUses only a 65 Hz bandwidth
- BDecodes signals with a very low signal-to-noise ratio Correct
- CSymbol rate is 65 baud
- DPermits fast-scan TV transmissions over narrow bandwidth
Why: JT65 decodes signals at very low signal-to-noise ratios.
- E2D06Question 6
Which of the following is a method for establishing EME contacts?
- ATime-synchronous transmissions alternating between stations Correct
- BStoring and forwarding digital messages
- CJudging optimum transmission times by monitoring beacons reflected from the moon
- DHigh-speed CW identification to avoid fading
Why: EME stations alternate time-synchronized transmissions.
- E2D07Question 7
What digital protocol is used by APRS?
- APACTOR
- BQAM
- CAX.25 Correct
- DAMTOR
Why: APRS uses the AX.25 packet protocol.
- E2D08Question 8
What type of packet frame is used to transmit APRS beacon data?
- AAcknowledgement
- BBurst
- CUnnumbered Information Correct
- DConnect
Why: APRS beacons are Unnumbered Information frames.
- E2D09Question 9
What type of modulation is used by JT65?
- AMultitone AFSK Correct
- BPSK
- CRTTY
- DQAM
Why: JT65 uses multitone AFSK.
- E2D10Question 10
What does the packet path WIDE3-1 designate?
- AThree stations are allowed on frequency, one transmitting at a time
- BThree subcarriers are permitted, subcarrier one is being used
- CThree digipeater hops are requested with one remaining Correct
- DThree internet gateway stations may receive one transmission
Why: WIDE3-1 requests three digipeater hops, with one remaining.
- E2D11Question 11
How do APRS stations relay data?
- ABy packet ACK/NAK relay
- BBy C4FM repeaters
- CBy DMR repeaters
- DBy packet digipeaters Correct
Why: APRS data is relayed by packet digipeaters.