Indoor Window Antenna – Part 2: Measured Results 📡
ADS-B (Automatic Dependent Surveillance–Broadcast)
ADS-B operates in the 1090 MHz band, which belongs to the UHF spectrum. The wavelength at this frequency is approximately 275 mm (10.83 inches).
Because the frequency is relatively high and the wavelength is short, the signal tends to propagate in a straight line.
In this respect it behaves somewhat like light: it does not easily bend around obstacles. Therefore reception becomes difficult in areas shadowed by objects such as buildings or mountains.
Aircraft transmit their transponder signals using this frequency, and ground antennas can receive these signals to track aircraft positions.
Because of these characteristics, terrain such as mountains may strongly influence reception patterns.
Half-wave dipole antenna
A half-wave dipole antenna is one of the most fundamental antenna designs. It consists of a conductor with a total length of approximately half a wavelength.
This antenna typically provides a gain of about 2.15 dBi and has a figure-eight radiation pattern.
The input impedance is around 73 ohms, making it highly efficient and easy to match with many radio systems.
Because of its simplicity and efficiency, the half-wave dipole is widely used in radio and wireless communication.
V-shaped dipole Antenna Specs
Length half-wavelength 10.8 inch(275mm)
Orientation 210°SW
Why chosen (ADS-B 1090MHz) Telescopic antenna
Measured Results
Statistics (early configuration)
Aircraft seen: 557
Max range: 66 nm
Gain: 38–40 dB
Antenna height: FL+70 inch (1788 mm)🐈️