The BeHear NOW and BeHear ACCESS headsets are Bluetooth Class II devices, while the HearLink PLUS is a Bluetooth Class I device. As a result, you many wonder what kind of transmission range you can expect with this product combination. Here is a detailed explanation:
- A Bluetooth link between two devices is always bi-directional. The actual range depends on radio performance of the transmitter and the receiver on the both sides.
- The difference between Class I and Class II Bluetooth devices in radio transmitting power is 16dB (Class I – 20dBm, Class II – 4dBm). Consequently, the power transmitted by a Class I device is ~40 times greater than that of a Class II device (10^(16/10)). The distance is a function of the square root of the power, meaning that the distance can be increased by ~6 times (SQR(40)) from 10m for Class II to 60m for Class I.
- In addition, a Class I device has improved receiver sensitivity (by ~4dB), which leads to an increased distance of ~1.5 times. Consequently, typical distance for Class I is 100m vs. 10m for Class II.
- When a Class I device is connected to a Class II headset the expected distance is as follows:
a. From a Class I transmitter to a Class II receiver – up to 60m (see paragraph #2)
b. From a Class II transmitter to Class I receiver – up to 15m (see paragraph #3)
c. For a bi-directional it is ~15m, based on the shortest range of #a and #b.
- HearLink PLUS as a Class I device provides additional improvements because of its dual-antenna design. The major effect is for the receiving part, since transmitting power is limited according to the standard. For communication with a Class II receiver, like our BeHear headsets, the distance is increased significantly because of this improvement. According to experimental data the operational distance for the HearLink PLUS and a BeHear NOW or BeHear ACCESS: up to ~60m (~200ft).