Lifts the fog of war over an area.

Gives you information on enemy units in the area. The better your decryption technology is versus their encryption technology the more info you can see (such as exact numbers, division types and roughly what battalions make up their divisions).

Increases chance of detecting and intercepting enemy ships (like submarines).

Improves chance for airplanes on interception and patrol to catch enemy planes. Generally leads to them outnumbering the enemy as planes can scramble to the same place more effectively.

Welcome to another development diary on Hearts of Iron IV.Today we’ll talk about one of the most important gadgets of WW2, the radio. The radio was used for communication and for propaganda. It was used on the battlefield, and in people’s homes.In our game, we have a technology called “Radio” which simulates adopting the inventions of amateur radio operators and extending the use of FM radio to reduce radio interference and allow us to find new uses for radio technology. This later on leads to the construction of Radar Stations. Looking closely at this technology tells us it gives +10% chance to reinforce.The radio technology also is a prequisite to be able to build Signal Companies for your divisions. Each of those increases your divisions initiative by 5%, which besides making planning quicker, also increases your reinforce chance.Now, veterans of HoI3 asks, why is reinforce chance important enough to mention in a development diary.First of all, there is a maximum combat width in a battle, and if that is exceeded, all divisions fight worse, and divisions will not join battle at all if it has a risk of giving too much of a penalty to a battle. The rest of the divisions ordered to defend or attack is held in reserves,Sometimes though, divisions gets knocked out of combat, or a tactic opens up bigger width, which allows a division to attempt to reinforce.However, only 1 division is checked each hour, and without radio, you may end up with divisions taking days to join a battle, and the actual battle then being long decided.Signal Companies use trucks and support equipment, and is one of the costliest support companies by far.Radar stations on the other hand are buildings you build on the map. Radar stations generally work so that higher building levels give you more range and many overlapping stations give you better effects. Radar does several things:Next week, we’ll talk about factories again, and what has changed since last time.