Hi
I made a set of these myself. I didnt have any equipment to tune or verify them, I also did paint them with PlastiDip.
Apparently PlastiDip aswell as many other paints will affect the tune quite a bit.
I put them on anyway and didnt find any diffrence from the stock antennas. I have 4 of them, both on the controller and the Solo.
I have no clue about how off i am in frequency and impedans, maybe with some tuning they can get better.
The other day I did order a small Vector Network Analyzer, the "MiniVNA Tiny". I hopefully get it some time next week.
I am really hoping that it will help me making these better.
When one googles this type of antenna, you hardly find any in the 2.4GHz range. They are mostly way bigger, aslo, they differ quite alot
from Andrew McNiels design in the linked video. While on his version, all the leads are connected to the inner line at the top of the antenna.
But every other version of it which i can find, has two circuits. Sorry, I have a hard time trying to explain, but english isn't my first language...
Just google QHF-antenna, and you see the diffrence from the one in the video.