2.3 Given a scenario, select and configure wireless devices and technologies
Frequency Options
📘CompTIA Network+ (N10-009)
Frequency Options: 2.4 GHz
In wireless networking, devices communicate using radio frequencies. The two most common frequency bands are:
- 2.4 GHz (Gigahertz)
- 5 GHz
Here, we focus on 2.4 GHz.
1. What is 2.4 GHz?
- 2.4 GHz is a radio frequency band used by Wi-Fi networks, Bluetooth devices, and some IoT devices.
- It is lower in frequency than 5 GHz, which gives it better coverage but slower speeds.
Key point for the exam:
2.4 GHz = longer range, slower speeds; 5 GHz = shorter range, faster speeds.
2. Channels in 2.4 GHz
- The 2.4 GHz band has 14 channels, but not all are used worldwide.
- Each channel is 20 MHz wide and channels overlap.
Important channels to know for the exam (non-overlapping):
- Channel 1
- Channel 6
- Channel 11
These channels do not overlap, so using them reduces interference.
3. Advantages of 2.4 GHz
- Longer Range:
- Lower frequencies penetrate walls, floors, and obstacles better.
- Good for devices in larger spaces or areas with many walls.
- Compatibility:
- Most devices support 2.4 GHz Wi-Fi.
- Older devices may only work on 2.4 GHz.
- Lower Power Usage:
- Devices using 2.4 GHz usually consume less power, helpful for IoT sensors or battery-powered devices.
4. Disadvantages of 2.4 GHz
- Slower Speeds:
- Maximum speed is lower than 5 GHz networks.
- Not ideal for high-bandwidth applications like video streaming or large file transfers.
- More Interference:
- Many devices use 2.4 GHz, such as:
- Bluetooth devices
- Microwave ovens
- Wireless phones
- This can cause network performance issues.
- Many devices use 2.4 GHz, such as:
- Limited Channels:
- Only 3 non-overlapping channels (1, 6, 11) → more interference in dense areas.
5. When to use 2.4 GHz in an IT environment
- Coverage is more important than speed:
- Office floors with thick walls
- Warehouses
- Outdoor Wi-Fi hotspots
- Connecting older devices:
- Some printers, scanners, and IoT devices only support 2.4 GHz.
- IoT and low-bandwidth devices:
- Sensors, cameras, and smart devices.
6. Exam Tips
When a CompTIA exam question mentions 2.4 GHz, remember:
| Feature | 2.4 GHz |
|---|---|
| Range | Longer, better through walls |
| Speed | Slower than 5 GHz |
| Interference | High (more devices on same band) |
| Channels | 14 total, 1, 6, 11 non-overlapping |
| Device compatibility | Most devices, including older devices |
| Best use case | Large coverage areas, low-speed devices |
Example exam scenario question:
You need Wi-Fi coverage throughout a large office with many walls and older devices. Which frequency band should you choose?
Answer: 2.4 GHz
7. Summary
- 2.4 GHz = long range, slower speeds, more interference.
- Best for large spaces, older devices, or low-bandwidth devices.
- Use channels 1, 6, 11 to minimize interference.
- Remember the trade-off: range vs. speed.
