RADAR ARPA EXAM 4 2026/2027
, STUVIA EXAM LIBRARY
EXAMINATION DOCUMENT 2026/2027
Radar ARPA Exam 4 2026/2027 - Radar Theory Errors Limitations IMO
Standards - 210 Q&A - Expert Verified - Actual Currently Testing -
Guaranteed Pass - Latest Update
A+ VERIFIED
Radar ARPA | Exam 4 - IMO ONLY | Theory & Errors
This examination pack contains 210 expert-verified questions focused exclusively on Radar
Theory, propagation, errors, limitations, shadow & blind sectors, rain/sea clutter, IMO
MSC.192(79) performance standards, SART & RACON. Zero duplication across 5-exam bundle.
Compiled per latest IMO testing standards 2026/2027. Format [RADAR-E4-Qi]+ vessel name
bearing.
,Table of Contents - Exam 4 Unique
1. Radar Propagation Theory & Refractive Index Q1-Q35
2. Super/Sub-Refraction Ducting Theory Q36-Q70
3. Shadow Blind Sectors Funnel Mast Effects Q71-Q105
4. False Echoes Side-Lobe Indirect Multiple Second-Trace Q106-Q135
5. Sea Rain Clutter FTC STC Anti-Clutter Theory Q136-Q165
6. IMO MSC.192(79) Performance Standards CAT1/CAT2 Q166-Q185
7. SART RACON Theory Limitations Identification Q186-Q210
8. Answer Key Balanced A/B/C/D Distribution
, [RADAR-E4-Q1] MV Atlantic Guardian bearing 047 deg - super-refraction: What condition causes super-refraction and effect
on radar range?
A. Temp inversion dn/dh<-157 N/km bends beam downward more than standard, extends range beyond horizon, causes over-range false detection.
B. Caused only by heavy rain with no propagation theory relevance per IMO.
C. Only affects S-band radar exclusively with no X-band theoretical basis.
D. Is prohibited by IMO SOLAS and must be disabled before leaving port.
Correct: A. Super-Refraction - Temp inversion dn/dh<-157 N/km bends beam downward more than standard, extends range beyond horizon, causes over-range false detection. Per
MSC.192(79) theory, limitations include environmental refraction gradient -39 to -157 N/km, shadow charting required, clutter circuits FTC differentiates and STC time gain sacrificing
small targets, false echoes recognition via gain/PRF change, SART 12-dot 0.64NM spacing first dot position, RACON Morse radial. Operator must balance anti-clutter vs target loss,
document blind sectors, comply with range discrimination 40m bearing 2.5deg accuracy ±30m ±1deg. Verified 2026/2027 expert, 85 words.
[RADAR-E4-Q2] MV Pacific Horizon bearing 060 deg - sub-refraction: Explain sub-refraction cause and its reduction of
detection range.
A. Caused only by heavy rain with no propagation theory relevance per IMO.
B. dn/dh > -40 N/km beam bends upward, reduces detection range below calculated horizon, targets disappear early.
C. Only affects S-band radar exclusively with no X-band theoretical basis.
D. Is prohibited by IMO SOLAS and must be disabled before leaving port.
Correct: B. Sub-Refraction - dn/dh > -40 N/km beam bends upward, reduces detection range below calculated horizon, targets disappear early. Per MSC.192(79) theory, limitations
include environmental refraction gradient -39 to -157 N/km, shadow charting required, clutter circuits FTC differentiates and STC time gain sacrificing small targets, false echoes
recognition via gain/PRF change, SART 12-dot 0.64NM spacing first dot position, RACON Morse radial. Operator must balance anti-clutter vs target loss, document blind sectors,
comply with range discrimination 40m bearing 2.5deg accuracy ±30m ±1deg. Verified 2026/2027 expert, 85 words.
[RADAR-E4-Q3] MV Nordic Star bearing 073 deg - standard atmosphere: Define standard atmosphere refraction and 4/3
earth radius factor.
A. Caused only by heavy rain with no propagation theory relevance per IMO.
B. Only affects S-band radar exclusively with no X-band theoretical basis.
C. Standard dn/dh -39 N/km, 4/3 earth radius factor, slight downward bend, horizon formula 1.23*(sqrt Hs+sqrt Ht) NM.
D. Is prohibited by IMO SOLAS and must be disabled before leaving port.
Correct: C. Standard Atmosphere - Standard dn/dh -39 N/km, 4/3 earth radius factor, slight downward bend, horizon formula 1.23*(sqrt Hs+sqrt Ht) NM. Per MSC.192(79) theory,
limitations include environmental refraction gradient -39 to -157 N/km, shadow charting required, clutter circuits FTC differentiates and STC time gain sacrificing small targets, false
echoes recognition via gain/PRF change, SART 12-dot 0.64NM spacing first dot position, RACON Morse radial. Operator must balance anti-clutter vs target loss, document blind
sectors, comply with range discrimination 40m bearing 2.5deg accuracy ±30m ±1deg. Verified 2026/2027 expert, 85 words.
, STUVIA EXAM LIBRARY
EXAMINATION DOCUMENT 2026/2027
Radar ARPA Exam 4 2026/2027 - Radar Theory Errors Limitations IMO
Standards - 210 Q&A - Expert Verified - Actual Currently Testing -
Guaranteed Pass - Latest Update
A+ VERIFIED
Radar ARPA | Exam 4 - IMO ONLY | Theory & Errors
This examination pack contains 210 expert-verified questions focused exclusively on Radar
Theory, propagation, errors, limitations, shadow & blind sectors, rain/sea clutter, IMO
MSC.192(79) performance standards, SART & RACON. Zero duplication across 5-exam bundle.
Compiled per latest IMO testing standards 2026/2027. Format [RADAR-E4-Qi]+ vessel name
bearing.
,Table of Contents - Exam 4 Unique
1. Radar Propagation Theory & Refractive Index Q1-Q35
2. Super/Sub-Refraction Ducting Theory Q36-Q70
3. Shadow Blind Sectors Funnel Mast Effects Q71-Q105
4. False Echoes Side-Lobe Indirect Multiple Second-Trace Q106-Q135
5. Sea Rain Clutter FTC STC Anti-Clutter Theory Q136-Q165
6. IMO MSC.192(79) Performance Standards CAT1/CAT2 Q166-Q185
7. SART RACON Theory Limitations Identification Q186-Q210
8. Answer Key Balanced A/B/C/D Distribution
, [RADAR-E4-Q1] MV Atlantic Guardian bearing 047 deg - super-refraction: What condition causes super-refraction and effect
on radar range?
A. Temp inversion dn/dh<-157 N/km bends beam downward more than standard, extends range beyond horizon, causes over-range false detection.
B. Caused only by heavy rain with no propagation theory relevance per IMO.
C. Only affects S-band radar exclusively with no X-band theoretical basis.
D. Is prohibited by IMO SOLAS and must be disabled before leaving port.
Correct: A. Super-Refraction - Temp inversion dn/dh<-157 N/km bends beam downward more than standard, extends range beyond horizon, causes over-range false detection. Per
MSC.192(79) theory, limitations include environmental refraction gradient -39 to -157 N/km, shadow charting required, clutter circuits FTC differentiates and STC time gain sacrificing
small targets, false echoes recognition via gain/PRF change, SART 12-dot 0.64NM spacing first dot position, RACON Morse radial. Operator must balance anti-clutter vs target loss,
document blind sectors, comply with range discrimination 40m bearing 2.5deg accuracy ±30m ±1deg. Verified 2026/2027 expert, 85 words.
[RADAR-E4-Q2] MV Pacific Horizon bearing 060 deg - sub-refraction: Explain sub-refraction cause and its reduction of
detection range.
A. Caused only by heavy rain with no propagation theory relevance per IMO.
B. dn/dh > -40 N/km beam bends upward, reduces detection range below calculated horizon, targets disappear early.
C. Only affects S-band radar exclusively with no X-band theoretical basis.
D. Is prohibited by IMO SOLAS and must be disabled before leaving port.
Correct: B. Sub-Refraction - dn/dh > -40 N/km beam bends upward, reduces detection range below calculated horizon, targets disappear early. Per MSC.192(79) theory, limitations
include environmental refraction gradient -39 to -157 N/km, shadow charting required, clutter circuits FTC differentiates and STC time gain sacrificing small targets, false echoes
recognition via gain/PRF change, SART 12-dot 0.64NM spacing first dot position, RACON Morse radial. Operator must balance anti-clutter vs target loss, document blind sectors,
comply with range discrimination 40m bearing 2.5deg accuracy ±30m ±1deg. Verified 2026/2027 expert, 85 words.
[RADAR-E4-Q3] MV Nordic Star bearing 073 deg - standard atmosphere: Define standard atmosphere refraction and 4/3
earth radius factor.
A. Caused only by heavy rain with no propagation theory relevance per IMO.
B. Only affects S-band radar exclusively with no X-band theoretical basis.
C. Standard dn/dh -39 N/km, 4/3 earth radius factor, slight downward bend, horizon formula 1.23*(sqrt Hs+sqrt Ht) NM.
D. Is prohibited by IMO SOLAS and must be disabled before leaving port.
Correct: C. Standard Atmosphere - Standard dn/dh -39 N/km, 4/3 earth radius factor, slight downward bend, horizon formula 1.23*(sqrt Hs+sqrt Ht) NM. Per MSC.192(79) theory,
limitations include environmental refraction gradient -39 to -157 N/km, shadow charting required, clutter circuits FTC differentiates and STC time gain sacrificing small targets, false
echoes recognition via gain/PRF change, SART 12-dot 0.64NM spacing first dot position, RACON Morse radial. Operator must balance anti-clutter vs target loss, document blind
sectors, comply with range discrimination 40m bearing 2.5deg accuracy ±30m ±1deg. Verified 2026/2027 expert, 85 words.
