Radars — CONVOY 1943

Read the cards

Ranges are shown in kilometres for readability; the simulation stores metres. “Reliability” and error values are simulation parameters. A radar can paint a return only when the contact, range, sweep, and profile rules all allow it.

Navigation means piloting aid here: a surface PPI gives the operator bearing and range to echoes so they can avoid hazards, hold station, or steer in darkness. It does not draw a route, steer the ship, or provide an autopilot.

Implemented · manual only

TYPE 271

Britain · profile year 1941 · surface search

Domain / face	Surface · A-scope
Coverage / sweep	360° · 6 s
Persistence	3 sweeps
Minimum / nominal	1.90 km / 20.00 km
Class limits	Battleship 20.00 · destroyer 15.00 · surfaced sub 9.20 · periscope 2.80 km
Accuracy / reliability	±2° bearing · ±5% range · 100%
Range scales	4.572 / 13.716 km (B1; B5 compatibility)
Identification	Mark III IFF to 20.00 km · no beacon mode

Can

Show surface, surfaced-submarine, and periscope-class echoes on an A-scope.
Provide live echo range and ship-relative or north-referenced bearing.
Use the generated manual antenna controls and radar IFF challenge.

Cannot

Detect air-domain contacts or present a circular PPI.
Rotate automatically; this profile requires manual rotation.

Vehicle sign: radar_type_271

Implemented · combined air / surface

TYPE 277

Britain · profile year 1943 · air / surface search

Domain / face	Combined · circular PPI / strobe
Coverage / sweep	360° · 6 s
Persistence	3 sweeps
Minimum / nominal	0.30 km / 73.00 km
Class limits	Battleship, destroyer, surfaced sub, periscope: 73.00 km each
Accuracy / reliability	±1° bearing · ±2.5% range · 89.5%
Range scales	18.20 / 36.50 / 73.00 km
Identification	Mark III IFF to 73.00 km · no beacon mode

Can

Paint both air and surface returns on a north-up or heading-up PPI.
Use the B7/N18/N19 target strobe for domain, range, and bearing.
Show 200 m-quantized aircraft altitude when the return is inside the ~40.2 km height-finding envelope.
Rotate automatically, with optional manual sweep controls.

Cannot

Guarantee all-altitude air warning or replace a fire-control solution.
Turn the PPI's gameplay domain label into automatic historical classification.

Vehicle sign: radar_type_277

Implemented · surface search

AN/APS-3

United States · profile year 1943 · maritime search

Domain / face	Surface · circular PPI
Coverage / sweep	360° · 6 s
Persistence	3 sweeps
Minimum / nominal	0.30 km / 74.00 km
Class limits	Battleship, destroyer, surfaced sub, periscope: 74.00 km each
Accuracy / reliability	±1° bearing · ±2.5% range · 89.5%
Range scales	18.50 / 37.00 / 74.00 km
Identification	Mark III IFF to 74.00 km · UPN-4 beacon homing to 111.00 km

Can

Search the surface through a full 360° PPI sweep.
Detect surface and submerged/periscope-class contacts according to the listed profile limits.
Use optional manual sweep, Mark III IFF challenge, and Radar Beacon Mode for coded UPN-4 replies.

Cannot

Detect air-domain contacts or supply the Type 277 height workflow.
Navigate or steer the aircraft automatically; the PPI is an operator aid.

Vehicle sign: radar_an_aps_3

Implemented · automatic rotation only

SO-1

United States · profile year 1942 · surface search / navigation

Domain / face	Surface · circular PPI
Coverage / sweep	360° · 5 s
Persistence	3 sweeps
Minimum / nominal	0.40 km / 37.04 km
Class limits	Battleship 37.04 · destroyer 28.00 · surfaced sub 9.26 · periscope 0 km
Accuracy / reliability	±2° bearing · ±2.5% range · 86%
Range scales	7.408 / 37.040 km
Identification	Mark III IFF to 37.00 km · no beacon mode

Can

Give a full-circle surface picture for piloting, station keeping, and dark-weather navigation.
Show destroyer/general-surface and surfaced-submarine returns within their profile limits.
Use automatic rotation, range selection, cursor readout, and Mark III IFF challenge.

Cannot

Detect air-domain contacts or periscope-class returns (profile limit is 0 km).
Use manual antenna slew; B2/B3/B4 are ignored.

Vehicle sign: radar_so_1

Implemented · automatic rotation only

SO-4

United States · profile year 1944 · surface search / navigation

Domain / face	Surface · circular PPI
Coverage / sweep	360° · 12 s (5 rpm)
Persistence	3 sweeps
Minimum / nominal	0.183 km / 37.04 km
Class limits	Battleship 37.04 · destroyer 29.632 · surfaced sub 12.964 · periscope 0 km
Accuracy / reliability	±1° bearing · ±1% range · 90%
Range scales	7.408 / 37.040 km
Identification	Mark III IFF to 37.00 km · no beacon mode

Can

Give a full-circle surface picture for piloting, station keeping, and dark-weather navigation.
Use the tighter X-band profile limits for surface, destroyer/general, and surfaced-submarine returns.
Use automatic rotation, range selection, cursor readout, and Mark III IFF challenge.

Cannot

Detect air-domain contacts or periscope-class returns (profile limit is 0 km).
Use manual antenna slew; B2/B3/B4 are ignored. The slower 12-second sweep can delay small-contact updates.

Vehicle sign: radar_so_4

Verified against the generated radar catalog, addon profile table, and per-radar used_on.txt guides on 12 August 2026. Source values are converted from metres to kilometres here. “Can / cannot” describes this implementation; it is not a historical fit guarantee.