Alright, so I have seen quite a few people asking how to lockette beacons, so I decided to post a tutorial.
This works with a beacon by itself or with a pyramid. Look in the screenshots for a visual representation.

Materials needed- a fence gate, a diamond pickaxe, a sign, and the beacon

Step One- Place the fence gate

Step Two- Place the beacon on top of the fence gate by shift- right-clicking the top

Step Three- Place the sign on the beacon, and type this-

[Private]
(username)

Step Four- Remove the fence gate

Congratulations, your beacon is now safe from griefers!

Post any questions or comments below!

 

Since a door/gate allows for a top or bottom block to protect it, I would like to test this with a door or gate on top of an anvil on Hellblock since the signs wont protect them. The gate would need to be on top since anvils fall.

 

Why is a diamond pickaxe required?

But good tutorial thanks for the info!

 

Well, assuming you have already placed the beacon, and you need a diamond pickaxe to break a beacon.

 

I use a similar method using a trapdoor. I might throw a quick video together and post it to go with this.

 

The fence gate method is easier, in my opinion.