What is the assigned bandwidth and channel...

🔍 Key Concepts

• SITOR (NBDP) emission designator J2B and what each part of that designator means • Typical frequency shift and channel spacing used for narrow-band direct-printing telegraphy in MF/HF maritime radio • Distinction between signal bandwidth (occupied bandwidth) and channel spacing in ITU allocations

💭 Think About

• First, recall the standard frequency-shift keying (FSK) values used for NBDP/SITOR in the MF/HF maritime bands. Which value in the choices looks like a common FSK shift? • Next, think about how much spectrum a narrow-band telex signal actually needs. Which options are clearly too wide for a narrow-band telegraphy mode? • Compare the smaller numeric pair in each answer: which pair looks like a realistic shift + channel spacing used to pack many telex channels into a small band?

✅ Before You Answer

• Confirm the typical FSK shift value used for maritime NBDP (SITOR) in ITU-R recommendations. • Check that the channel spacing is significantly larger than the shift to allow for guard band between channels. • Eliminate options whose bandwidth values are more appropriate for SSB voice (around 2.4–3 kHz) rather than narrow-band telegraphy.

What is the assigned bandwidth and channel spacing for J2B SITOR (NBDP) transmissions?

3.1 kHz and 4.0 kHz

2.8 kHz and 3.0 kHz

170 Hz and 300 Hz

300 Hz and 500 Hz

🔍 Key Concepts

💭 Think About

✅ Before You Answer