this is like magic roundabout,
in their own words from the avanti astrobeam article eddie showed me, the avanti engineers said they did not understand how the astroplane worked even though they made it,
if they don't understand the astroplane they don't understand the sigma4 either,
w8ji makes sense with his isolation ideas to me but i also have broadcast fellows telling me he's wrong to claim that a 4 radial groundplane needs to be isolated,
we have people claiming that a 1/2wave endfed does not need radials,
my own experience with the 1/2wave a99 following w8ji's ideas,
we found that isolating the mast, adding 1/4wave wire radials and choking the feedpoint cured terrible biting rfi/tvi in the shack AND improved signal strength,
removing the radials but leaving the mast and choke causes the rfi to return,
im open minded to the idea that the manufacturers don't know what they are talking about with regards to how to install their product,
none of the antenna manufacturers tell you to isolate the antenna, in fact when i brought up w8ji's isolation ideas jay and others claimed the 4 radials decouple the mast/feedline and needs no isolation,
we even have claims that the mast radiation is beneficial to the vector4000 ( i don't buy that ),
when the 5/8wave is isolated and choked and still loses to the vector is that just the 9+feet of height advantage of the current maxima ?
who do you ask when the smartest antenna guys you know of don't agree.
