OK, "Albrecht's" is ambiguous because it could be an abbreviation of "Albrecht his" OR "Albrecht is". The context removes the ambiguity - "Albrecht is radar says..." is gibberish, so we know he meant "the radar of Albrecht says..."
Albrechts' is not ambiguous because it's a plural noun, and the plural form of the verb to be is 'are', and so you can't abbreviate "Albrechts are" to Albrechts'. Albrechts' radar is the radar belonging to Albrechts.
(the same construct is also used on singular nouns that end in 's', in which case I think the ambiguity may be possible again). Albrecht with his award may know more
But it is semantically wrong because the Albrecht in question is singular.