To create a new radio beacon tower, place an iron block next to powered redstone.
The redstone current activates the antenna and it begins broadcasting signals within
a three-dimensional spherical range, available to be received by other fixed antennas
(simply click the iron block to show the received signals) or mobile radios
(compasses held in your hand automatically scan for signals periodically).
Extending Range: To transmit and receive further, place any number of iron bars on top of the iron block.
As you build up, the new antenna radius will be shown to you in the chat area. The
antenna tip can be destroyed to decrease the radius, or broken in the middle, and it
behaves as you would expect, broadcasting from the highest contiguous iron bar.
Setting Messages: Attach a sign to the side of your fixed antenna base, and the text of the sign will
automatically be included in the transmission.
Relay Antennas: Built using a gold block instead of an iron block, relays
retransmit messages from nearby antennas. To set a relay message, build a normal antenna
within range and set its message. All relays within range will be notified using a special signal.
Relays retain their message even if the original antenna is destroyed, so they can be used to add redundancy
or extra range.
Weather: Rain decreases the transmission and reception radius. Thundering slightly increases it,
but lightning has a chance to strike antennas, causing their destruction.
Mobile Radios
Fixed antennas can receive and transmit, but are limited by their lack of mobility.
Compasses serve as mobile radios, allowing for both receiving signals and navigating
to their origin.
To receive transmissions, hold a compass in your hand. It will continuously scan and
report any nearby signals, their range, and message (if any). Switching to another item
will turn off scanning.
To tune into a signal, left- or right-click the compass. The next scan will report
which signal you have locked onto, and the compass needle will point in its direction.
If it interferes with other plugins which use compasses, players can turn off their
radios using the /toggleradio command.