All three are valid ways to read a target's range. Range rings give a quick estimate, the cursor reads out range to wherever you place it, and the VRM gives you a settable circle for precise measurement.

The X-mile rating is the radar's maximum settable range — a hardware capability, not the current setting.

EBL = Electronic Bearing Line, a rotatable line from the centre used to read bearings. STC and FTC are clutter controls; VRM measures range.

VRM = Variable Range Marker, an adjustable circle used to read ranges precisely.

Traditional Head-Up has no heading input — the boat's bow points straight up, the heading line is fixed at 000° Relative, and EBL readings are Relative bearings (off the bow). To get a True or Magnetic bearing you must add the actual heading and convert.

In Burch's terminology, a portable range scale is literally a hand-drawn ruler-like strip that matches the range-ring spacing — used to measure distances anywhere on the screen, not just from centre.

A track-ball cursor combines bearing + range read-outs on the position you point at — exactly what EBL and VRM do separately.

Magnetic bearing = Magnetic heading + Relative bearing (mod 360). 040° + 097° = 137°M. Variation isn't needed because you stay in magnetic throughout.

225° + 314° = 539°, − 360° = 179° M.

340° + 241° = 581°, − 360° = 221° M.

Run the Plymouth Sound, UK scenario in Radar Trainer 3 to verify.

Run the Plymouth Sound, UK scenario in Radar Trainer 3 to verify.

Run the Plymouth Sound, UK scenario in Radar Trainer 3 to verify.

Run the Plymouth Sound, UK scenario in Radar Trainer 3 to verify.

Compute from the two-end measurements (or read directly using a portable range scale across both ends).

Run the Plymouth Sound, UK scenario in Radar Trainer 3 to verify.

Run the Plymouth Sound, UK scenario in Radar Trainer 3 to verify.

Run the Plymouth Sound, UK scenario in Radar Trainer 3 to verify.

Run the Plymouth Sound, UK scenario in Radar Trainer 3 to verify.

A small low target like a single light is below the radar's minimum detectable signal threshold at longer ranges; closing the range raises the return above noise and makes it visible. This is a common practical limitation — small targets need close range to be detectable.

Open the AS-1 PDF to confirm. The bearing read-out (BRG / TRG) on the screen capture is the answer; the lat/lon-style reading (47° 35.2') is a position, not a bearing.

Standard watch-handover etiquette: before touching anyone else's radar settings, confirm with the person on nav that it's OK. Their gain/range/clutter setup may have been tuned for tracking a specific target.

Recreational and most coastal-cruising marine radars are X-band (~9.4 GHz, 3 cm wavelength) — smaller antennas, finer angular resolution, good for navigation. S-band is mostly on commercial/offshore vessels for long-range and rain penetration.

At 1–2 m from a typical marine radar antenna you are still in the near field, where the inverse-square law (1/r²) does not apply — power density is roughly constant. You only get the 1/r² fall-off once you're in the far field, which for a typical radome is ~10× the antenna dimension out.

Higher transmit power is a property of the larger radar units that open arrays come with, not a property of the antenna geometry per se. Beamwidth and rotation speed don't change radiated power — only the transmitter does.

Marine radar exposure is governed by recommendations (ANSI / IEEE / FCC / IEC / ICNIRP) rather than enforceable US federal regulations specific to recreational marine units, and the recommended numerical thresholds vary across agencies.

Standard Starpath response window is 48 hr. If it's been longer, contact helpdesk@starpath.com or call 206-783-1414.