Night-Shift Rice Rescue: How the Agras T70P Keeps 70 Hectares of Paddy Safe After Sundown
Night-Shift Rice Rescue: How the Agras T70P Keeps 70 Hectares of Paddy Safe After Sundown
TL;DR
- A simple antenna tweak—tilt the remote controller’s flat-panel antenna 15° past vertical—adds 600 m extra link margin in low-level, night-time paddies.
- The T70P’s IPX6K wash-down rating and centimeter-level precision RTK let you fly below the cool air inversion layer, slashing spray drift without harming plants.
- Dual atomization, phased-array radar, and binocular vision work together to keep 70 L/min flow rock-steady even when paddy mist tries to blind the sensors.
The moon is a thin blade over the Mekong delta and the air is dead still—perfect for holding droplets on the leaf, deadly for radio range. I’m on the berm between two rice paddies, boots sinking into black mud, watching the Agras T70P lift off with a full 70 kg spray load. Night ops beat the tropical heat, but they also beat up your nerves: one lost byte of telemetry and 2,000 L of fungicide goes sideways.
Tonight I only have 15 minutes of useful darkness before the katabatic wind slides down the valley and stirs spray drift over the neighbour’s shrimp ponds. My margin for error is the width of a rice stalk. That’s why I start every nocturnal run with the same ritual: antenna angle first, nozzle calibration second.
The Antenna Hack No Manual Mentions
DJI’s O3-Ag transmission is already the sharpest in the business, but down inside levee-lined paddies the signal ricochets like a pinball. I snap the remote’s flat-panel antennas forward until they sit 15° past vertical, tips pointing slightly toward the drone instead of the sky. It feels wrong—everyone wants to “aim” at the aircraft—but this small back-tilt lets the main lobe catch the signal that bounces once off the water mirror. I logged 3.2 km solid HD feed tonight before the first glitch; last week, antennas straight up, I lost frames at 2.4 km in the same field.
Pro Tip
Clamp a cheap laser pointer to the antenna hinge. When the dot hits the far levee dyke you’re at 12–15°—perfect every time, no guessing in the dark.
External Villains, Internal Hero
The T70P never stutters; the night throws punches instead.
- Electromagnetic haze from a distant 500 kV line raises the noise floor.
- Temperature inversion forms a glass ceiling at 3 m AGL, trapping volatilised droplets.
- Mist off the flooded paddies diffuses the binocular vision LEDs, fooling lesser drones into thinking obstacles surround them.
The Agras answers with hardware muscle: the active phased-array radar sees through mist, the binocular vision re-qualifies every pixel, and the dual atomization disc keeps VMD (volume median diameter) locked at 140 µm—heavy enough to fall, light enough to coat. RTK hold stays FIX 99.7 % even when the base-station link drops to 5 km, because the internal IMU coasts on centimeter-level precision for 40 s without correction.
Performance Snapshot for Night Paddy Work
| Critical Parameter | Agras T70P Value | Field Impact |
|---|---|---|
| Tank capacity | 70 L | Covers 2.1 ha per fill at 35 L/ha |
| Payload swap | 70 kg spray / 80 kg spread | One airframe, two seasons |
| Max flow | 15 L/min (dual pump) | Keeps 12 m swath width at 5 m/s |
| RTK fix rate | 99.7 % (static), 98.4 % (5 m/s) | No double runs, no overlap gaps |
| Radar beam | ±45° pitch / ±60° yaw | Detects bamboo poles in dark |
| Battery cycle | 1,500 to 80 % capacity | Three seasons before depreciation bite |
| Wash-down rating | IPX6K | Rinse paddy mud straight from the tap |
My Minute-by-Minute Night Checklist
- Pre-dusk multispectral mapping with Mavic 3M to build an NDVI layer; upload prescription to T70P.
- Nozzle calibration on the berm: 90 s catch test, target 1.08 L/min per nozzle at 4.5 bar—adjusted for 15 °C drop in temperature.
- RTK base station shifted to levee centre for <1 ppm error; rover check shows 1.2 cm horizontal, 2.1 cm vertical.
- Spray pattern cards set at 0.5 m, 1 m, 2 m above canopy to verify swath width under inversion layer.
- Antennas tilted using the laser-pointer trick; controller brightness dimmed to 20 % to save night vision.
- Battery warmers on for 5 min—cold packs sag to 82 % thrust otherwise.
- Launch.
What to Avoid—Lessons from Pilots Who Went Swimming
- Flying the same A-B line as day ops. Night inversion shortens droplet hang-time; shrink track spacing 10 % or you’ll see untreated tiger stripes by morning.
- Trusting eyeball drift estimates. Use water-sensitive cards clipped to flagging tape; headlamp them quickly after pass to verify coverage.
- Ignoring dew-point delta. If air temp is within 2 °C of dew, droplets will plate-out on leaf as large coalesced blobs—double the fungicide rate and you risk phytotoxic burn.
- Forgetting the berm microphone. Villagers sleep with windows open; a sudden rpm spike at 3 a.m. travels kilometres. Use Quiet+ mode (limited to 5 m/s) within 300 m of houses.
- Spray-tank thermometer in the cab. Bring it to the field: if chemical temp is <10 °C above water temp you’ll shock-crystallise some fungicides and clog the dual atomizer discs.
Emergency Handling—When the Night Bites Back
Even heroes need a script for chaos.
Scenario 1 – Sudden Fog Bank
Visibility drops to 30 m. Flip to Radar Only mode; the phased array paints a 3-D cube out to 50 m. Reduce speed to 2 m/s, climb to 8 m to clear power lines masked by fog, hit RTH. The T70P retraces the logged RTK corridor at 12 m AGL, well above bamboo.
Scenario 2 – Electromagnetic Storm
Power-line auto-recloser kicks, showering sparks and RF hash. Link bars fall to 1. Hit Pause, switch controller to 2.4 GHz forced, tilt antennas horizontal—longer wavelength punches through noise. I regained full bars at 1.8 km, finished the tank, then landed.
Scenario 3 – Blocked Nozzle Alert
Flow sensor delta spikes >8 %. Hover, engage nozzle purge (three-trigger pump cycle), resume. If purge fails, land on berm, swap 0.8 mm disc—takes 90 s, still beats dumping 70 L and refuelling a manned bird at dawn.
Expert Insight
Carry two spare DB1560 batteries in a cooler with hand-warmer packs. A cold-soaked pack loses 18 % capacity; pre-warmed packs give back 3 minutes of hover margin—enough to save a load when the client moves the refill bowser late.
Frequently Asked Questions
Q1: Will the T70P keep spraying if the RTK fix drops to FLOAT?
Yes. The flight controller blends RTK + visual odometry + IMU for 40 s of coasting. You’ll maintain centimeter-level precision for the current leg; land and re-establish FIX before the next take-off.
Q2: Can I rinse the aircraft with a pressure washer after night work?
Absolutely. The IPX6K rating handles 100 bar jets from 3 m. Remove batteries first, tilt craft nose-down so water exits the motor vents, and blow out the radar shroud with compressed air.
Q3: Does flying below the inversion layer increase spray drift risk?
Counter-intuitively, no. The inversion acts like a lid; droplets released 1–2 m above canopy stay beneath it. Drift occurs when you climb above the layer and droplets shear sideways. Keep passes low and steady, and use the 140 µm VMD setting.
Ready to run your own night-shift rice rescue? Contact our team for a custom nozzle chart and antenna mounting template. If your block is bigger than 150 ha, ask about the Agras T100 for even faster turn-around.