How does this spawner farm work?
I've seen a few different mob spawner farm designs around. Lots of people seem to like this one:

The idea, as far as I understand, is that mobs spawn in the air and fall down through the water suspended by signs. They then get sucked into the "funnel", pushed over to the water ladder (which they climb by swimming up), then dropped to near-death.
I've seen farms like this in operation in SMP, so I understand the basic principle. However, I attempted to build one from this schematic, and it doesn't seem to be working. It seems that the mobs are able to float / swim up on the water blocks below the spawner (above the signs), meaning they never actually fall to the bottom to get sucked up the latter.
As so many people seem to like this design, I'm willing to bet that I made a mistake. However, looking at the schematic, I see two different places -- the aforementioned water and the water block at the beginning of the "funnel" -- where mobs could get stuck. How is this farm supposed to work, then?
Best Answer
I have used a similar design many times. My designs did not use the top layer of signs and water in the spawning area. Just 2 source blocks in the spawning area, along with a single source block on the bottom to push the mobs to the elevator sufficed. (Roughly in release 1.7.4 was the last time I used/built one of these).
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How do you use a farm spawner?
The spawner spawns mobs in a 9\xd73\xd79 volume (see \xa7 Mechanics) around it when the player is within 16 blocks. Suitable spawning locations for the block's mob type are provided in or around the spawning volume. The spawner attempts to spawn four mobs around it, then waits from 10 to 39.95 seconds before spawning more.How does a spawner work?
Spawners can be picked up with silk touch, but they can only be reactivated on top off a full tier beacon piramid.Can Silk Touch 1 pick up spawners?
Silk Touch II will allow you pick up monster spawners, the dragon egg, and silverfish stone without spawning a silverfish. The silverfish stone will drop as itself and not the variant of stone it's disguised as.Minecraft Mob Spawner Explained [Tutorial]
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Answer 2
Here I have some modifications hat might work:
Raise the sighns and the waterblocks all by one in the spawning room (except those on the ground).
Delete the water and the sign under the spawning room because it is useless.
at the beginning of the elevator change it to this patren:
B ^ B
B W B
B S B B B B B B
B W S (mobs come through here)
B H F F F F F F
B B B B B B B B
B = block, S = sign, W = water source, H = half slap, ^ continue the elevator here.
- Instead of the block you have placed in your room, place a half slap
Answer 3
Possible modification: create the recommended 2x2 column and place the signs so that they are properly spaced. Also, make the design as friendly as possible to the clumsy mobs. Few designs are foolproof (mob-proof).
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Images: Quang Nguyen Vinh, Quang Nguyen Vinh, Quang Nguyen Vinh, Quang Nguyen Vinh
