A short write up of recon related aspects in Squad Battles:
To determine base LOS, use the S hotkey.
If within the base LOS of any enemy unit, a unit is revealed to the opponent at the start of the next turn/phase
if any of the following applies:
- the unit is in open terrain
- the unit is an infantry unit in terrain with a height of 1m but not in ground mode
- the unit is a vehicle unit
In addition, if within base LOS of an enemy unit, any unit is revealed IMMEDIATELY
in these circumstances:
- the unit fires
- the unit moves INTO a hex that is within base LOS of the enemy [a yet unrevealed unit stays revealed if it moves from a hex (in which it was concealed) within the enemy’s LOS into a hex not within the enemy’s LOS]
- the unit does something suspicious in its current hex (rally, load/unload, use detection object)
- the unit is revealed by a special detection item (see manual, p. 49-50)
Once revealed, units stay revealed unless the enemy’s base LOS to the unit is cut. So, for example, you cannot crawl into an ambush position that is already within sight of the opponent.
INFO ON REVEALED UNITS
The information you get on a revealed enemy unit depends on whether the enemy unit is currently positioned in terrain that offers concealment (terrain height 2+m) or not (0-1m terrain height).
terrain height 0-1m
Exact number of men
all weapon types available in the unit (but not their actual number)
unit status (disrupted, pinned, demoralized)
you get accurate information on any casualties you inflict
dropped weapons are visible
terrain height 2m+
approximate number of men (X, 1X, 2X, etc.)
Unless the unit has previously been spotted, only those weapons who have actually fired are visible for the opponent. (Note that when a unit moves into a concealed hex within LOS of the enemy, then all weapons are revealed.)
unit status (disrupted, pinned, demoralized)
you don’t see any casualties you might be inflicting on the opponent (no casualty marker pops up when you fire on a unit in 2+m terrain)
dropped weapons are not visible
NOTE: Unfortunately, river beds and gullies do not count as 2m+ height terrain for concealment purposes.
REVEALING DEFENSIVE WORKS
Unless they’re within a 2m height terrain hex, defensive works are spotted at the start of the next turn/phase
if they're within base LOS of the enemy.
Additionally, defensive works are immediately
revealed if any unit in them is revealed.
The number of tracers that a unit fires indicates the relative effectiveness of the unit’s fire (4 tracers = 100%, 1 tracer = 25%).
RECON BY FIRE
Note that you can fire at any hex within a unit’s LOS (or even not in LOS, if you have indirect fire weapons). There is no need to have spotted an opponent. However, any fire against yet unspotted units is only half as effective (*0.5)
LIGHTS/ILLUMINATION AND SPECIAL DETECTION DEVICES
More systeamtical attempt to describe illumination devices:
- Illumination rounds/flares (7 hexes, illuminated): When you fire an illumination round at a hex, that hex and a radius of 1 hex around it (total 7 hexes) will be illuminated for one full turn (Note you can see which hexes are illuminated: view/shade/illuminated hexes). Any units whose LOS to the illuminated hexes is otherwise not blocked (by terrain) will get a normal LOS on the illuminated hexes. As you would expect, illumination is one-sided. Units in the dark can see the illuminated hexes, but not vice versa: units in the light cannot see into the dark. NOTE: Units in the dark that fire on you are not revealed. You will be able to see their tracers though (so you can tell their exact hex).
- IR searchlights (10 hexes, IR-illuminated): You can fire IR searchlights at any hex within the range of the searchlight and within your theoretical LOS (not blocked by terrain, only by the lack of daylight). Note that the shot is treated as an indirect fire shot, so it scatters (up to 1 hex + 1 hex per 10 hexes distance) It's not entirely clear to me what happens then: The shot seems to affect a total of 10 hexes 1) I suppose that spotting checks are conducted against all the affected hexes (manual p.49). Any enemies you may spot will vanish after that turn (you need to spot them again next turn). 2) Any of your units that have some IR capability may target any of the IR-affected hexes (usually, you're not allowed to fire beyond max. visibility), however, any fire into hexes that are exclusively IR-illuminated may scatter up to 1 hex. NOTE: IR searchlights are also used in opportunity fire (against targets within theoretical LOS). So, when you see your IR-searchlight opportunity-fire, you know that there's something out there in the bush! NOTE: Your opponent can always see the impact animation of the IR searchlight, so he also knows against which hexes you're trying to spot. The unit that fires the IR searchlight, however, stays concealed.
- Ordinary searchlights (10 hexes, illuminated): They work similarly to IR searchlights: you can fire them at any hex within your theoretical LOS and within range of the searchlights, the shot is treated like an indirect weapon, i.e. it may scatter, and it will affect an area of 10 hexes. Also, an illumination marker is placed for each shot. The affected area is illuminated for 1 full turn (see above illumination rounds/flares). Note that the fire animation as well as the illumination markers are visible to the enemy.
- NV sights (7 hexes, spotting check): wip
illuminates target area (varibale size, weapon dependent --> check the "Exp radius" of the ammunition) for 1 full turn, shot scatters (it is typically fired by mortars...), firing unit is not revealed, concealed units in target area stay concealed, animation visible for the opponent, consumes illumination allowance
illuminates target area (10 hexes) for 1 full turn, shot scatters (up to 1hex+1hex per 10 hexes distance), firing unit is revealed, concealed units in target area stay concealed, animation is visible for the opponent, consumes illumination allowance
IR-affects target area (10 hexes) for 1 full (?) turn, CHANCE to spot unconcealed enemy units in target area, shot scatters (as above), firing unit is not revealed, concealed units in target area stay concealed, animation visible for the opponent, may opportunity-fire; any unit with some IR capablity (or NV sights, it seems...) may fire at any IR-affected hex, but the shots will be indirect (scatter), does NOT consume illumination allowance
affects a target area (7 hexes), shot scatters (as above), firing unit is not revealed, concealed units in target area may be spotted (?, I suppose that this is why the weapon is marked with #), animation is visible for the opponent, does NOT consume illumination allowance; [who can fire on the spotted units?]