10 October 2018

NILE/Link-22 waveform #2 (S4539 Annex D)

STANAG-4539 HF Fixed Frequency TDMA transmission, used by NILE/Link-22, spotted on 7606.0 KHz/usb and followed from 0905z up to 0950z (October, 9). Modem for HFFF TDMA operations are described in Annex D of STANAG-4539.
The 270 symbols of the Media Code Frame in this samples are arranged according to the QPSK Traffic Waveform #2 (WF2) consisting of 8 sections with 18 symbols data blocks and 15/16 symbols mini-probes.

Other NILE/Link-22 waveforms, all characterized by having the same 112.5ms ACF value, are discussed here.

Fig. 1
Fig. 2

As in the table below, there are six sections consisting of 18+16=34 dibit symbols (ie 68 bits) and two sections consisting of 18+15=33 dibit symbols (ie 66 bits). Using the time shift cursor of the tool in Fig. 2 you may get the same order of the sections which is shown in the table.


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