>>You can probably get away without the
>>3rd, if there's any directionality to the signal at all...it's only if
>>it's omni-directional that you'd need them all.

>That's what I thought at first too. I think it depends on whether
>you're triangulating based on distance or direction.

Hence my comment about not needing the third, if you get any directionality from the observations :)

The impression I got, from the story is that Len only sensed distance, not direction (and for that matter, not a very precise distance...oh heck, lemme go find the quote...)

Then, just as he was about to give up and let the pattern
collapse, he saw it - a faint red pinpoint, impossibly far away.  He
abandoned the rest of the search and threw all his will at improving
his view of that one light.  The distance was astonishing; if this was
who he was seeking, she must be in another galaxy!

Hmm, well that does seem to indicate directionality, actually... but useful enough for triangulation, I suspect...if they could get enough other data points. Ah, well; I suspect The Authors will find some way to render all this speculation moot :)