In this video, I demonstrate how much better your signal is with Alientech vs. Occursync 2.0. The difference is pretty dramatic.
You can get the alientech at covertdrones.com. I had a great experience with him doing my installation for me. Keep in mind this is amplified not passive like 4hawks. He has them for all drones so not limited to Autel as shown in this video but can personally attest to how well it does work on the Evo II Pro 6k. This demonstrates why you might need one even at short ranges. In my case, the houses are all block wall with rebar for the hurricane standards here in FL thus tons of interference.
If you have the Smartcontroller, you can get it for that which is a great option so you have extended range for all your drones.