Thanks to all the many respondents to my question! The good news is, that
following the general concensus that the coax length does not matter I
pursued the shorter length again today, resited the wire antenna (G30JV
80plus2) to another location, and the analyer I have now indicates a
distinct improvement. What was throwing me was some stuff I read somewhere
about using odd halfwave length multiples for coax runs - but perhaps this
was another myth!

Thanks Guys

Keven