Q1: Can LoRa modules reliably reach 4 km with 20 drones?

Yes, LoRa modules on 868/915 MHz can reach 4 km in ideal line-of-sight conditions. However, real-world range depends on antenna placement, height, and interference. For 20 drones, proper airtime scheduling is needed to avoid collisions.

رادیوهای مقرون به صرفه غیر 2.4 گیگاهرتز برای ازدحام هواپیماهای بدون سرنشین

Q: Q2: Why avoid 2.4 GHz for this swarm?

2.4 GHz is crowded and more susceptible to interference from Wi-Fi, Bluetooth, and other devices. Lower frequencies like 433 MHz, 868/915 MHz, or 1.2 GHz provide better propagation and reliability, especially for long-range telemetry and control.

Q: Q3: Can this setup stay under $100 per drone?

Yes, hobbyist-grade LoRa, ExpressLRS, or 433/900 MHz telemetry radios can often be sourced under $100 per unit. Costs may rise if you need higher transmit power, professional-grade modems, or specialized antennas for guaranteed range.

فهرست مطالب

Choosing Cost‑Effective Non‑2.4 GHz Radios for a 20‑Drone Master‑Slave Swarm

اخیراً, we received an inquiry from a UAV operator looking to implement a master–slave drone swarm with very specific requirements:

“Do you have any communication systems that should not work on 2.4 GHz for swarm 20 هواپیمای بدون سرنشین?
We are using master–slave configuration looking for a 4 km LOS and 1.5 km AGL height.
Looking for a cost-effective solution, video transmission is not required.
Is there any solution under 100 USD or below per unit? These are for target drones; they will be destroyed.
وجود دارد 19 slave drones which will be in a pattern and placed 5 meters apart.
The master drone will be 20 meters apart. Must be gas, non‑2.4 GHz.”

Let’s break down the requirements and explore practical, low-cost communication solutions for this scenario.

Key Requirements

Master–Slave Swarm: 1 master + 19 slave drones.
Drone spacing: Slaves ~5 m apart; master ~20 m apart.
Communication range: قابل اعتماد 4 کیلومتر (line-of-sight) links.
Altitude: تا 1.5 km AGL.
Data type: Telemetry/control only — no video.
Frequency constraints: Must avoid 2.4 گیگاهرتز.
Budget: Ideally ≤ $100 per unit, since drones are expendable.

Technical Considerations

Frequency Band Trade-offs

Lower frequencies such as 433 مگاهرتز, 868/915 مگاهرتز, یا 1.2 گیگاهرتز propagate farther and are more reliable than 2.4 گیگاهرتز, making them ideal for long-range telemetry. These bands are commonly used in hobbyist and industrial UAV telemetry systems.

دامنه در مقابل. Antenna and Power

آ 4 km LOS link is achievable with moderate transmit power, good antennas, and clear LOS. Antenna height, به دست آوردن, and polarization are crucial for maintaining reliable connections.

Network Topology

In a star topology با 19 slaves, collision management is important. Using LoRa, ExpressLRS, or similar radios, you need to consider protocol design to avoid packet collisions and latency issues.

Regulatory Considerations

Frequency bands and transmit power are regulated by country. Always check local rules (FCC, این, و غیره.) before deployment. This is particularly important for low-cost long-range radios.

Cost and Performance Trade-offs

While hobbyist modules can achieve 4 km LOS under ideal conditions for <$100, professional long-range telemetry radios often exceed $100. Testing is essential to validate performance in real operational conditions.

Practical Options

لفظی / SX127x Modules (868/915 مگاهرتز)
- جوانب مثبت: Very low cost ($30–$60 per unit), long-range in LOS, robust interference immunity.
- منفی: Low data rates, potential duty cycle restrictions, longer latency.
900 MHz Telemetry Radios / ExpressLRS Modules
- جوانب مثبت: تأخیر کم, widely used in UAV control, robust link, can support multiple nodes.
- منفی: Modules with guaranteed long-range may exceed $100; cheaper modules require careful setup and tuning.
433 مگاهرتز / 1.2 GHz Modules
- جوانب مثبت: Excellent propagation, ideal for low-cost expendable drones.
- منفی: Large antennas may be required, regulatory limits vary by region.

Recommendations

Prototype First: Test a small swarm (1 master + 3–5 slaves) to verify range, تاخیر, and collision management.
Choose the right protocol: Ensure the radio supports multiple slaves or implement a simple polling schedule.
Optimize antennas: Proper placement, به دست آوردن, and polarization often have a bigger impact than transmit power.
Stay legal: Follow local frequency and power regulations.

پرسش و پاسخ

Q1: Can LoRa modules reliably reach 4 km with 20 هواپیمای بدون سرنشین?

آره, LoRa modules on 868/915 MHz can reach 4 km in ideal line-of-sight conditions. هر چند, real-world range depends on antenna placement, قد, and interference. For 20 هواپیمای بدون سرنشین, proper airtime scheduling is needed to avoid collisions.

Q2: Why avoid 2.4 GHz for this swarm?

2.4 GHz is crowded and more susceptible to interference from Wi-Fi, بلوتوث, and other devices. Lower frequencies like 433 MHz, 868/915 MHz, or 1.2 GHz provide better propagation and reliability, especially for long-range telemetry and control.

Q3: Can this setup stay under $100 per drone?

آره, hobbyist-grade LoRa, ExpressLRS, or 433/900 MHz telemetry radios can often be sourced under $100 per unit. Costs may rise if you need higher transmit power, professional-grade modems, or specialized antennas for guaranteed range.

نتیجه گیری

For a cost-effective, non-2.4 GHz master-slave swarm, the most practical solutions are:

LoRa/SX127x modules (868/915 مگاهرتز) for low-rate telemetry.
900 MHz telemetry radios / ExpressLRS for low-latency control.

Both approaches can fit a <$100 budget per drone in open-field LOS. Real-world performance depends on antennas, protocol design, and regulatory limits. آ prototype test is essential before scaling to 20 هواپیمای بدون سرنشین.