I'd never heard of "Nectar". That's a new one on me. If they discarded it, it wouldn't necessarily be because it could be confused with "Echo". The whole idea was that it shouldn't sound close to ANY other English word, so that someone not familiar with the phonetic alphabet would still recognise it. Nectar would sound fairly close, especially in crackly static conditions to Hector, Lecture, Sector, Rector (well. you never know who might be on the other end) or Vector.