All, Received several emails from fellow hams asking if I would run PAX and HF Packet through the HF path simulator. Finished testing today and the results show that PAX is clearly the better mode (see below).
It had a 3db SNR advantage while testing for sensitivity (no ionospheric distortion) and did much better when subjected to ionospheric path simulations. The simulations seem to indicate that the HF Packet mode is susceptible to the kind of small-scale instability that's always present on signals refracting from the ionosphere. This would explain the modes poor performance in practice when conditions are relatively quiet. Tony, K2MO _____________________________________________________________ PAX: Sensitivity threshold for 100% decode: -2db (no ionospheric distortion) Ionospheric Simulations: High-Latitude Moderate.........Complete decdoe @ +2db SNR. Partial decode 0db SNR High-Latitude Disturbed........NO DECODE REGARDLESS OF SNR Mid-latitude Disturbed.........Complete decode @ +1db SNR. Partial Decode @ -2db SNR Low-Latitude Disturbed.........NO DECODE REGARDLESS OF SNR HFPAcket (300baud) Sensitivity threshold for 100% decode: +1db SNR (no ionospheric distortion) Ionospheric Simulations. NO DECODE REGARDLESS OF SNR* * Susceptible to slight multi-path timing delays (< 1msec) and Doppler Spread (< 1Hz)
