|Frequencies||1525 MHz,1559 MHz|
|Frequency Range||1525 MHz - 1559 MHz|
|Short Description||Inmarsat D+ (and it's predecessor, Inmarsat D) was Inmarsat's satellite paging system. The main use of the technology was in tracking trucks and buoys and SCADA applications.|
|I/Q Raw Recording||Download file|
Inmarsat D+ (and it's predecessor, Inmarsat D) was Inmarsat's satellite paging system. The main purpose was for tracking trucks and buoys and SCADA applications. The original Inmarsat-D terminals were one-way (to mobile) pagers. The newer Inmarsat-D+ terminals were the equivalent of a two-way pager. This signal is the downlink from satellite to mobile station. The infrastructure is now rendered obsolete by the newer IsatData Pro service.
The downlink comprises a 32 MFSKMultiple Frequency Shift-Keying signal at symbol rates of 4 sym/s or 8 sym/s for data rates of 20 bpsBits per second (bps) and 40 bpsBits per second (bps) respectively. Reed-Solomon (31,15) FECForward Error Correction is used on downlink.
The 4 sym/s signal has shift of 20 HzHertz (Hz), unit of frequency, defined as one cycle per second (1 Hz). for each tone. The bandwidth of the signal is ~640 HzHertz (Hz), unit of frequency, defined as one cycle per second (1 Hz)., but the channel allocated to the downlink is 2.5 kHzKiloHertz (kHz) 10^3 Hz wide to account for doppler shifting interference. There is a frequency shift of 20 HzHertz (Hz), unit of frequency, defined as one cycle per second (1 Hz). for each tone.
Inmarsat Downlink @ 4 sym/s:
(Sample contributed by RAPIDBIT)
(Sample contributed by UHF-SATCOM)
IQQuadrature signals form the basis of complex RF signal modulation and demodulation, both in hardware and in software, as well as in complex signal analysis. Sample contributed by RAPIDBIT
- Rx (Downlink): 1525.0 to 1559.0 MHzMegaHertz (MHz) 10^6 Hz
- Tx (Uplink): 1626.5 to 1660.5 MHzMegaHertz (MHz) 10^6 Hz
- UHF Satcom Inmarsat D
- DMR200 Specs (Inmarsat D+ compatible)
- Inmarsat-D identified, Reddit
- FCC Public Notice
- LXE Inc. FCC Form 312 – Notification of Minor Modification