What do LF, HF and UHF stand for?
Just like the radio we listen to, radio frequency tags and readers need to be modulated to the same frequency to work. LF, HF, UHF correspond to radio frequencies of different frequencies. LF stands for low frequency radio frequency at around 125KHz; HF stands for high frequency radio frequency at around 13.54 MHz; UHF stands for ultra high frequency radio frequency in the range of 850 to 910 MHz.
What is the effective range for the reader to receive radio waves?
The receiving range of the reader is affected by many factors, such as radio frequency, tag size and shape, reader energy, interference from metal objects, and other RF devices. In general, the receiving distance for low-frequency passive tags is within one foot, the receiving distance for high-frequency passive tags is about three feet, and the receiving distance for UHF tags is ten to twenty feet. For semi-active and active tags that use batteries, the reader can receive signals three hundred feet or more. For low-frequency and high-frequency RF, if the tag and reader antenna are the same size, the receiving distance can be calculated by multiplying the diameter of the antenna by 1.4. This rule applies to diameters up to thirty centimeters.