I did not follow the whole conversation. Anyway, spread spectrum has following benefits as far as I am known:
It allows more stations to use the spectrum. The trick is in spreading the signal by a sequence, which appears to be random. Many stations transmitting spread spectrum signals at various time and frequency offsets will all together resemble white noise. On the contrary, many conventional narrow band signals will approach white noise much slower. There is a classic article from Costas (of the PSK Costa's loop decoder algorithm) explaining why even DSB has theoretical benefits over SSB because it spreads the signal to higher bandwidth, which makes the total interference look more like white noise. The spreading in frequency makes the signal less sensitive to narrow band carriers, it makes it difficult to jam a signal by a single or couple of carriers. The other benefit is critical to military use. It is difficult to detect and if one does not know the spreading sequence, it is impossible to decode. Spread spectrum somehow contradicts the HAM radio philosophy. Spread spectrum to be useful mandates the software itself to identify and lock to the signal. It is impossible identify weak SS signal from white noise by ears. The operator will just enumerate the channels and the machine will do the rest. Higher amount of SS stations at the same frequency will increase background noise, so it will create an interference to let's say a CW operator. Therefore one would need to dedicate SS channels, otherwise there would be plenty of complaints from CW operators. I don't see a real benefit in running SS signal in just 2.5kHz SSB bandwidth. Olivia or MFSK will do better because they use the whole spectrum for itself, while SS on purpose leaves all the orthogonal spreading sequences to be used by other stations. For the same bandwidth, SS is designed to share frequency, classic multitone signals for best coding gain. That is a whole world of difference. SS would be very beneficial for beacon network, where all beacons share the same channel. This is what the GPS satellite network does indeed. SS may be used for single channel world wide chatting mode. One will be able to decode many signals at once with powerful computer. 73, Vojtech OK1IAK
