This thing might work or might Not.
There is No mention or dealing correctly with the real variables that counts in Antenna.
One or two additional Bars means nothing if the Signal to Noise Ratio (SNR), and Standing Wave Ratio (SWR) are larger too.
In principle you can try the same thing for another frequency by adjusting the size.
I.e. since the variable that was used in the video is wave length for Antenna size, 5GHz is twice of 2.4GHz make every thing half the size (larger frequency is smaller wave length).
However without real measure of SNR and SWR, it might be useless.
http://www.ezlan.net/wbars.html
