7047.45 (centre) has been used for FSK300 IL2P packet for some time now, but suffers from bad general QRM / other digital mode traffic.

There is a carve-out in the UK 40m band plan for unattended digital modes at 7050 to 7053. ETCC have been perfectly willing to grant FACs within that carve-out for UK packet radio stations.

There is a known long-standing source of QRM at 7055 LSB (3kHz), rendering the top 1kHz of the carve-out compromised.

Known UK users have now migrated to that carve-out, as follows:

NinoTNC tone frequency is 1500Hz for BPSK, 1700Hz for FSK.

“Centre” means the spot frequency on which the mode's RF energy, whatever the mode, should be centred. As a convenience, I have included the dial frequency (the frequency you set your radio's VFO to) required for the NinoTNC (different per mode).

All dial frequencies are USB.

NinoTNC does not support ARDOP.

Graphical representation:

The end result should be three separate data channels, co-existing harmoniously within a single ~1.8kHz audio passband, with less QRM from other band users / intruders.

With 500Hz occupied bandwidth, there is 150Hz guard between slots.

With 600Hz occupied bandwidth, there is 50Hz guard between slots.

We will be close together, but not overlapping. It is important to be accurate with frequency selection.

Precise occupied bandwidth is dependent on both the mode and the particular modem implementation.

QPSK2400 (~2.4kHz occupied bandwidth for 2400bps) has proven too difficult for the SNRs we can practically achieve on 40m HF NVIS.

BPSK300 should provide around 7dB more sensitivity than FSK300, all else being equal.

IL2P+CRC is favoured over IL2P since the data corruption rate with straight IL2P was unacceptably high in practice on HF.