# L36 Pre-flight **Block 4: Aircraft Survivability and Mission Planning — Lesson 36: SEAD, Maneuvers, and Standoff Jamming** *Work this before L36. Pre-flights are never collected — in class, anyone may be cold-called to present any question at the board, and that recitation is the participation grade.* --- ## Assumed pre-class reading - L17's jam-to-signal ratio, $J/S = 4\pi P_jG_jR^2 B_r/(P_tG_t\sigma B_j)$, the burn-through range, and the self-protect versus stand-off distinction; L5's Doppler shift $f_d = 2v_r/\lambda$ and the MTI notch; L6's sidelobes. - The Jupyter Book Reading page for L36 — SEAD suppression versus destruction and the suppression window, the beam/notch maneuver, the standoff $J/S$ with its two ranges ($R_t$, $R_j$) and two gains ($G_r$, $G_r'$), standoff burn-through, the jammed contour and its strobe, and the scalings $R_{bt} \propto R_j^{1/2}$ and $R_{bt} \propto (G_r'/G_r)^{-1/4}$. --- ## Quiz questions (5 items, ~5 minutes) **Q1.** (Multiple choice) A standoff jammer (SOJ) orbits 140 km due west of a SAM acquisition radar that has a 4° beam and −30 dB sidelobes. Four strike packages are each 35 km from the radar. Which package gets the **shortest** burn-through range — the one the SOJ protects best? - [ ] (a) The package 35 km due east of the radar, on the far side from the SOJ - [ ] (b) The package 35 km due north of the radar, square to the SOJ's line - [ ] (c) The package 35 km due west of the radar, between the radar and the SOJ - [ ] (d) The package 35 km southwest of the radar, 45° off the SOJ's line --- **Q2.** (Multiple choice) One radar, one SOJ. A package off the jammer's azimuth is burned through at 32 km, where the jamming enters through the radar's −24 dB sidelobes. The package turns onto the jammer's azimuth, with the SOJ, the radar and the target unchanged. Its new burn-through range is: - [ ] (a) 2.0 km - [ ] (b) 8.0 km - [ ] (c) 32.0 km - [ ] (d) 127.4 km --- **Q3.** (Multiple choice) An SOJ 100 km from a radar holds a package's sidelobe burn-through range to 20 km. A newly located SAM forces the SOJ to back off to 225 km to stay outside that SAM's MEZ plus the keep-out margin; the radar, the package's azimuth and everything else are unchanged. The new sidelobe burn-through range is: - [ ] (a) 13.3 km - [ ] (b) 24.5 km - [ ] (c) 45.0 km - [ ] (d) 30.0 km --- **Q4.** (Multiple choice) An X-band tracking radar ($\lambda = 3$ cm) uses MTI that rejects every return with $|f_d| < 2$ kHz. An aircraft at 250 m/s wants its echo inside that notch. It must fly: - [ ] (a) Within 6.9° of the beam, perpendicular to the line of sight - [ ] (b) Within 13.9° of the beam, perpendicular to the line of sight - [ ] (c) Within 6.9° of nose-on, flying straight at the radar - [ ] (d) Within 83.1° of the beam, perpendicular to the line of sight --- **Q5.** (Short answer) (i) Distinguish SEAD **suppression** from **destruction**, and give one lethal and one non-lethal means. (ii) A package's time inside one SAM's lethal zone runs from 0410 to 0418; the suppression of that SAM runs from 0400 to 0415. What happens to the package, and name two ways the planner could fix it.