Globe Wireless HF Network

Globe Wireless HF Network
Frequencies	3 MHz,30 MHz
Frequency Range	3 MHz - 30 MHz
Mode	USB
Modulation	PSK,FSK,OFDM
ACF	—
Emission Designator	—
Bandwidth	400 Hz,750 Hz,2 kHz
Location	Worldwide
Short Description	Globe Wireless' Maritime Digital Radio was a system of 24 stations around the globe offering data services to large cargo vessels. Since 2014, GW has discontinued their HF network.
I/Q Raw Recording	—
Audio Sample

Globe Wireless's HFHigh Frequency (3-30 MHz) Network was a system of 24 stations around the globe offering data services to large cargo vessels. Since 2014, GW has discontinued their HFHigh Frequency (3-30 MHz) network, and the company has been purchased by Inmarsat, which is focusing primarily on satellite networks. Globe Wireless was a provider of HFHigh Frequency (3-30 MHz) and satellite email and data services to the shipping industry.

The remnants of the Globe Wireless network is scattered all over the world. Parts of the HFHigh Frequency (3-30 MHz) network are now used by Swisscom, including its own Bern Radio in Switzerland. [1] [2] Swisscom solely uses PACTOR III with huffman compression for data transfer. [3]

Modes[edit]

There are a number of modes that were used with Globe Wireless, including their own proprietary ODFM DQPSKDifferential Quadrature Phase-Shift Keying modes used for data transmission.

GW-FSKFrequency-Shift Keying:
- GW-FSKFrequency-Shift Keying is Globe Wireless's "Idle Channel" or "Free Signal" marker. It is continuously broadcasted from shore stations out to sea, and ships use them to know which channel has the best signal quality if they want to establish a connection. Has a bandwidth of 400Hz and operates as Simplex ARQAutomatic Repeat reQuestAutomatic Repeat Query.
GW-PSKPhase-Shift Keying:
- GW-PSKPhase-Shift Keying is also used in place of FSKFrequency-Shift Keying depending on the propagation situation. Also operated with 400Hz bandwidth and Simplex ARQAutomatic Repeat reQuestAutomatic Repeat Query.
GW-OFDMOrthogonal Frequency-Division Multiplexing (Orthogonal Frequency-Division Multiplexing):
- GW-OFDMOrthogonal Frequency-Division Multiplexing is the main data mode for Globe Wireless. GW-OFDMOrthogonal Frequency-Division Multiplexing uses DQPSKDifferential Quadrature Phase-Shift Keying with OFDMOrthogonal Frequency-Division Multiplexing modulation and features adaptive speed with modes from 12 to 32 sub-carriers with 62.5Hz sub-carrier spacing. They are chosen dynamically based on the noise level and propagation ability. The bandwidth range for OFDMOrthogonal Frequency-Division Multiplexing is from 700-2700 HzHertz (Hz), unit of frequency, defined as one cycle per second (1 Hz)..
GW-CLOVER-400 with SITOR:
- Before GW-OFDMOrthogonal Frequency-Division Multiplexing and the FSKFrequency-Shift Keying/PSKPhase-Shift Keying modes, Globe Wireless used SITOR as the "Idle Channel", as SITOR was more ubiquitous at the time among the maritime industry. To transmit data, Globe Wireless partnered with HAL Communications to develop a special proprietary mode, CLOVER-400, that could be used for shore to ship communications. It was a special variant of CLOVER that only occupied 400Hz of bandwidth, which met FCC requirements (FCC Part 80.211 (f) Limits). The shore stations would transmit first in SITOR. If they were able to identify a ship that was CLOVER-400 compatible, they would switch to CLOVER to transmit the data.