I want to increase the PWR of my USB Wi-Fi adapters to get better result with weak APs.

I am using 3 different Wi-Fi adapters:

G-Sky GS-27 USB with Realtek 8187L chipset.

ALFA AWUS051NH with Ralink RT2870/3070 chipset.

Powerlink Premiertek PL-18N with Ralink RT2870/3070 chipset.

The G-Sky GS-27 USB with Realtek 8187L chipset shows 20dBm tx-power. I have increased the tx-power from 20 to 30dBm.

There are still APs that show PWR 68-75 and I want to increase the range, so the PWR is in 40 to 50 range.

I am considering to buy a panel directional antenna like these below:




Is it worth it to invest for this kind of antenna to increase the PWR and range or what is the best way to go?

Thank you for any advice.