Recently, while browsing Chinese shopping websites, I came across an interesting 1090MHz active antenna. The seller provided the following specifications:
Operating Frequency Bandwidth: 1090MHz ± 15MHz
Output Impedance: 50Ω
Gain: 23.15dBi
Noise Figure: NF < 0.75
Bias Voltage: 5V
Length: 180mm
Diameter: 25mm
Weight: 78g
Upon inquiring further, I learned from the seller that the antenna is not made from printed PCB elements and they sent me internal pictures of the antenna.
I am not an antenna expert, so I am curious about the authenticity of these specifications. When compared to typical passive antennas, does this active antenna offer any advantages? I would appreciate your insights.