What is the correct frequency shift and...

Question 1 / 27070nI14oRMxzVreTnOy2Ces

Question 1 of 27070nI14oRMxzVreTnOy2Ces

What is the correct frequency shift and sub-carrier for MF-HF-DSC?

Question 1 of 27070

What is the correct frequency shift and sub-carrier for MF-HF-DSC?

🔍 Key Concepts

• Digital Selective Calling (DSC) modulation characteristics for MF/HF bands • The meaning of frequency shift in frequency-shift keying (FSK) for DSC • The definition of sub‑carrier frequency in MF/HF-DSC systems

💭 Think About

• Which ITU or GMDSS specification defines the exact MF/HF-DSC modem characteristics, including the frequency shift and sub-carrier? • Think about typical FSK frequency shifts used for narrowband maritime DSC – are they usually very large (hundreds of Hz) or more modest? • Compare the given sub‑carrier options (1500, 1700, 1900 Hz) with the commonly standardized DSC audio sub‑carrier used in MF/HF systems.

✅ Before You Answer

• Verify the standard DSC FSK shift used on MF/HF bands as specified by ITU-R or GMDSS documentation • Confirm the standard audio sub‑carrier frequency assigned to MF/HF-DSC (it is a single, well‑known value) • Eliminate options whose frequency shift looks atypically large for narrowband FSK DSC applications

Question 1 of 27070

What is the correct frequency shift and sub-carrier for MF-HF-DSC?

+/- 85 Hz and 1700 Hz

+/- 170 Hz and 1700 Hz

+/- 250 Hz and 1500 Hz

+/- 400 Hz and 1900 Hz