If using 14.073, be sure to avoid interference with the JT65 or FT8 area. A reminder, QRP is a power reference, not a mode. We do not wish to cause interference to each other. PSK31 ops are on 14.070 and the QRP club uses 14.060 as their calling frequency. The lower frequency is the same as that of the sync tone used in long messages, and the frequency separation is 110250/4096 = 26.92 Hz multiplied by n for JT65A, with n = 2, 3, 4 used to convey the messages RO, RRR, and 73. Note 1: For 20 meter ops, the FHC calling frequency is 14.063 and UP to 14.069. Shorthand messages for RO, RRR, and 73 dispense with the sync vector entirely and use time intervals of 16384/11025 = 1.486 s for pairs of alternating tones. It is conveyed by reversing sync and data positions in the transmitted sequence. Modulation is 65-FSK at 11025/4096 = 2.692 baud.įrequency spacing between tones is equal to the keying rate for JT65A, and 2 and 4 times larger for JT65B and JT65C.įor EME QSOs the signal report OOO is sometimes used instead of numerical signal reports. ![]() The synchronizing tone is normally sent in each interval having a “1” in the sequence. A Reed Solomon (63,12) error-control code converts 72-bit user messages into sequences of 63 six-bit information-carrying symbols. The author labled this mode as a 65-FSK modulation so this is why it is under FSKĪ detailed description of the JT65 protocol was published in QEX for September-October, 2005.
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