On Sep 23, 4:16 pm, Jim-NN7K . wrote:
Realistically, it
probably makes little difference, overall, but was a sales pitch,
started by AEA, on its Isopole antenna.

I saw a large difference when I tested mine. Using stable local
signals to test, I often saw 3-4 S units worth of difference on
the old IC-22u I was using at that time.
But the difference will vary to each installation, length of coax,
etc... It's even possible for the common mode currents to add
in phase and cause an increased gain, but that is very rare.
The decoupling kit makes the antenna work the same no
matter the length of coax, etc..
Well worth the trouble I think.
BTW, I've compared the decoupled cushcraft to the isopole.
The decoupled cushcraft was close, much closer than the
non decoupled version, but the isopole was still the best
by a slight margin. The isopole was probably the best dual
5/8 antenna ever made as far as decoupling the line.
But for the money and slimmer looks, the 2B cushcraft is
pretty good. I used one for a long time.
MK