I did some highly scientific testing tonight...
Tests
10ft apart
No aerials on either - IS 77 IM 70
1 stubby aerial horizontal – IS 88 IM 57
2 stubby aerials horizontal – IS 69 IM 41
2 stubby aerials 1 hoz 1 vert – IS 65 IM 35
2 stubby aerials vertical – IS 52 IM 23
1 stubby, 1 long both vertical – IS 46 IM 23
2 stubby vertical + adptr - IS 75 IM 47
I couldn't get two long aerials to work... not sure why, but does this mean that 2 right angle adapters (in my last example) would be pretty poor? Seems to be worse that 2 stubby aerials horizontally.