so ive been running an inverted V for 40m for a couple years now, apex at about 35 feet with the ends dropping down to maybe 8 feet off the ground on each side. works ok but i keep reading that a flat top dipole at the same apex height would outperform it, especially at lower takeoff angles for dx. my problem is i only have the one tall support (a pine tree roughly in the middle of the yard) so a flat top would mean the ends are also at 35 feet which means i need two more supports at the far ends of the lot.

anyone actually done a side by side comparison or modeled both configs? i ran it through mmana-gal once and the flat top showed better gain at low angles but honestly i wasnt sure i set up the inverted V geometry right in the model. the ground constants i used were probably wrong too.

also my lot is kind of irregular shaped so one end of the dipole would be closer to the house foundation than id like. not sure how much that matters at 40m wavelengths. anyway curious what people have actually experienced not just what the modeling says

the modeling is roughly right in my experience. flat top at the same apex height does give you a cleaner pattern and a bit more oomph toward the horizon compared to the inverted V, but honestly at 35 feet on 40m youre not exactly working miracles either way. the inverted V compresses the pattern more toward straight up which isnt terrible for domestic stuff and regional contacts but yeah if you want to work europe from the states on 40 the flat top will help.

the foundation thing on 40m is probably not a huge deal if youre talking a few feet of separation. id worry more about it on 80 or if you were building something with a very low impedance feedpoint. the ground losses on 40 at those frequencies tend to average out over a bigger area anyway. if you can get even a temporary second support — even a painters pole zip tied to a fence post or something — it might be worth trying the flat top just to hear the difference yourself. thats really the only way youre gonna know for your specific location.

i went through this exact thing last summer. ended up just putting up a cheap 20 foot fiberglass push up pole from dxengineering at one end and that gave me enough height to run a flat top at about 28 feet across the whole span. not quite 35 feet but close enough. difference on 40m was noticeable on dx, i was actually getting into JA on gray line which the inverted V only did occasionally. the other end of my dipole is close to my shed and i havent noticed any issues tbh