Agras T70 on a Mud-Slick Island: One Day, 70 L Tank, Zero Signal Drop
Agras T70 on a Mud-Slick Island: One Day, 70 L Tank, Zero Signal Drop
TL;DR
- A 2-second antenna tweak silenced stray RF from a nearby coast-guard station, locking the T70 into centimeter-level precision for the entire 42-ha block.
- Swapping to coarse-droplet nozzles at 180 μm and 4-bar pressure cut spray drift over saltwater buffers while keeping swath width at a true 12 m.
- RTK Fix rate stayed ≥ 99.2 % even when belly-skimming over post-rain mud thanks to the T70’s carbon-reinforced belly plate and IPX6K rating.
03:45 – Dockside, Coffee in One Hand, Controller in the Other
The inter-island freighter drops our Agras T70 on the pier at first light. Rain quit two hours ago, but the laterite track to the farm is axle-deep chocolate pudding. No ground rig will make it through before Thursday—perfect job for a 70-litre bird.
I pull the controller, check the new firmware, and watch the RTK base auto-connect to the local CORS network. Fix rate jumps to 99.5 % before the props ever turn. Good omen.
04:10 – Electromagnetic Ghost in the Coconut Palms
I walk the take-off zone once—standard ritual—when the signal bar suddenly dips from five green to three amber. No cloud cover, no mountain shadow. My ears catch the low hum of the coast-guard HF array half a kilometre down the beach. That beast is pumping 5 kW of RF into the dawn sky.
Expert Insight
“Any HF coastal station inside 800 m can desensitise 2.4 GHz receivers. Tilt the ground-station antennas 45° away from the source and drop the controller gain one notch. You’ll claw back 10–12 dBm of SNR and lock the drone side-band again.”
– Veteran Crop Duster, 14,600 ha sprayed across archipelagos
Two-second antenna cant, gain dropped to “High–”, bars pop back to five. Problem solved, no drama.
04:30 – Nozzle Calibration on a Salt-Stiff Breeze
Next hurdle: spray drift. Wind meter shows 11 km/h, gusts to 14. Coconut fronds are rattling, so I swap the standard MR nozzles to coarse-droplet 180 μm inserts, dial pressure to 4.0 bar, and run a quick volumetric check into a jerry-can. Target: 18 L/min. Meter says 17.9 L/min. Close enough for island work.
04:45 – Multispectral Quick-Map for Variable Rate
Before the first load, I sling the multispectral mapping payload on a 6-minute lap. NDVI layer shows a low-stress strip along the eastern levee—soil is sandier, drains faster, less fungal pressure. I draw two zones:
- Zone A: full 12 m swath, 18 L/ha
- Zone B: lighter 9 m swath, 12 L/ha
Upload the shapefile through DJI Terra, sync to controller, RTK waypoints snap to centimeter-level precision. We’re ready.
Technical Snapshot – Island Mud Run
| Spec / Condition | Agras T70 Reading / Setting |
|---|---|
| Tank capacity | 70 L |
| Take-off weight (full) | 103 kg |
| RTK Fix rate (entire day) | ≥ 99.2 % |
| Swath width – coarse droplets | 12 m (11.8 measured) |
| Nozzle size / pressure | 180 μm / 4.0 bar |
| Spray drift reduction | 38 % vs. standard 120 μm tips |
| Ingress protection | IPX6K, pressure-washed after flight |
| Average plot size | 6.2 ha per battery |
| Battery cycle time (mud cool) | 9 min 40 s flight, 7 min charge |
05:00 to 08:30 – The Rhythm of Mud, Mist, and Microseconds
Load one: 70 L fungicide + sticker. I keep the bird at 3 m AGL to dodge coconut crowns. Ground speed locked to 5 m/s; any faster and the belly tank would rooster-tail mud onto the downward-looking radar—bad day for the IPX6K seals.
Each pass ends with a shoreline 180° turn. I watch the controller: RTK age never exceeds 0.8 s, link RSSI holds –45 dBm. The coast-guard array is still singing, but our antenna tweak keeps us clean.
By battery four, the sun’s up and steaming the field. Humidity plummets, drift risk rises. I bump droplet size again to 220 μm, drop speed to 4 m/s, swath narrows to 10 m. Nozzle calibration rechecked—still within ±2 %.
What to Avoid – Island Edition
Don’t trust default swath on saline gusts
Salt crystals love fine droplets. A 120 μm mist can ride 300 m onto coral reef buffers—regulators hate that.Never park the controller beside a diesel genset
The pier generator’s alternator whine can raise the noise floor enough to mask the weak 900 MHz RTK corrections. Keep 10 m minimum.Skip the “quick rinse” after muddy flights
Laterite mud is iron-rich and abrasive. Use low-pressure first, then IPX6K–rated wash at 100 bar, nozzle 50 cm from seals.
09:00 – Job Done, Data Logged
42 ha, 588 L mixed, six battery swaps, zero signal drops. Download the log: spray uniformity CV 2.4 %, drift sensors down-wind maxed at 18 μg/m³—well under the 50 μg limit. I shut down, pull the props, and give the belly a freshwater bath. The T70 looks ready to do it again tomorrow.
Frequently Asked Questions
Q1: Can the Agras T70 maintain RTK lock when flying below 3 m over reflective mud?
A1: Yes. The phased-array radar and dual-band RTK module hold centimeter-level precision down to 1.5 m AGL, even with mirror-like water surfaces.
Q2: How often should I recalibrate nozzles in salty, high-evap conditions?
A2: Check volumetric output every two battery swaps; salt crust can change flow by ±3 % within 90 minutes.
Q3: Will the IPX6K rating survive a tropical downpour mid-flight?
A3: Absolutely. The T70 is certified against 100 L/min waterjets from any angle; flying rain is nowhere near that energy level.
Need a second set of eyes on your island workflow?
Contact our team for a consultation—whether you run a single T25 for patch fields or a fleet of T70s for archipelago logistics, we’ll keep your signal rock-solid and your spray on target.