In message , Peter
writes
Hi all

I have just modelled both the Slim Jim antenna and J Pole antenna using
MMANA-GAL at the same frequency (145MHz) all other parameter equal and was
some what surprised that they appear exhibit the same gain and radiation
pattern. Based on an article I read in a English magazine many years ago I
have always believed the Slim Jim had a slight edge over the J Pole.
Wonder if others had a similar view and if my modelling is correct are there
any advantages with the Slim Jim design?

Some websites indicate that the only significant difference is that the
Slim Jim has a somewhat wider bandwidth. Unfortunately, I can't
instantly find a good reference. Here's one, but not too good.
--
Ian