In this thread it would be great to hear about people’s homebrew antennas that were ambitious but that for whatever reason underwhelmed when it came to performance. Given that we learn from others via books and websites, there is nothing like failing a few times yourself to teach you some good lessons! But we rarely hear about other people’s failures. The point of this thread is to tell others about stuff that was built that sounded like it should work, but that didn’t live up to expectations. I will start off the thread with the story of my stealth 7 element Yagi for the 10m band – around 1977. This antenna had a boom length of something like 40 feet, 7 elements and was not rotatable - it was just wires stapled to the roof of my dad’s house! I started with just the driven element, which was a standard dipole fed by RG8. I cut it to the “correct” length for 28.2 MHz and found it was nowhere near resonant! Lesson 1: nearby conductors make a difference… The house has aluminum rain gutters and whilst there was virtually zero wiring in the attic there was enough interaction with conducting stuff that the resonant length had to be materially adjusted. I kept this percentage adjustment in mind, contacted a nearby ham buddy who was luckily directly in the (theoretical) beam path and got a signal report. I had worked out the beam direction to be Santa Barbara, CA - you can see I had high hopes! I didn’t have access to a great circle bearing calculator, so tediously worked out the math myself (and got it wrong numerous time initially). I then added a reflector that was several percent longer (guided by the 1976 ARRL Antenna Book for the section on shorter Yagis I expect) and got signal reports from my buddy, adjusting the director spacing for max gain. Then I added a director that was several percent shorter than the driven element, optimized it with my buddy (each time I had to go up a ladder onto the roof of the 2 story house to move the element). Note that I didn’t go back and check whether the spacing from driven to reflector was still optimal, but I was too impatient for that! And I was taking up a lot of my buddy's time... Finally it was done but annoyingly had quite a low 2:1 SWR bandwidth – less than 300kHz from memory, maybe due to using wire, and it never hit 1:1, which at the time I thought was a problem. I seem to remember the spacing of elements 4 and outward was wider than the first 3 elements and was about uniform-ish. The directors all had shortened by a bit – can’t remember how I worked that out - it may have been a guess. Just as I was finishing this project my friend and quasi-Elmer W9MZZ gave me an old 3 element 10m beam! I cleaned it all up and built a tower out of wood about 20-some feet tall that could tilt-over onto the house roof so I could make adjustments. I got an old TV rotator and used that to turn the beam – what a joy! Then came comparisons with the 7 element beam: in the direction with the most gain, which was slightly off bore (?!?) it was at best only about 1-2dB better than the 3 element beam! I had expected more like 4dB better for some reason. I also found that the F/B ratio was terrible, and that I could hear signals off the sides pretty well. When the 10-X contest came up, we were lucky with a few openings and I found that using the roof beam I could hold a frequency and run Californians for hours – using the 7 element beam! But it was later clear from QSL cards I got that the contacts were not concentrated in Santa Barbara - more like San Diego/LA. Knowing what I think to be true now, the roof beam never had a chance of performing like a true 7 element yagi. For one thing, all the elements were inverted vees, which are more or less omnidirectional when you have a 120 angle, which I think was ballpark the roof angle. I expect that an EZNEC analysis of such a thing would show that it performs nowhere near a real Yagi even in free space. So there’s my ambitious antenna that underwhelmed. Let’s hear about yours!