Antenna selector circuit using PIN diodes

This antenna selector circuit diagram is designed using common electronic components and is very useful when are used many external antennas .
This antenna selector circuit diagram uses PIN diodes which eliminate disadvantages of mechanical switches (especially at high frequency current) PIN diodes can be used which are ideal for this purpose.
Resistance diodes such changes linearly in a wide range of current values. This feature is ideal for a number of applications: by changing the current-biased, the PIN diode can be used for mitigation, equalization or amplitude modulation of high frequency signals.
Capacitors C1 ... C4 and C9 are used for preventing the entry and exit DC circuit. L1 shock ... L5 prevent leakage to the table, the bar food, the HF signal. Resistances R2 ... R5 ensure that their unused diode anodes to be connected to ground, so that it is impossible to mix different antenna signals.
L1 shock ... L5 can be wound on a ferrite core, using enamelled copper wire of 0.3 mm diameter, two turns will be enough entries for the VHF UHF and 5 (1 uH is required for UHF and VHF about 5 uH). The circuit was designed for antennas with input impedance of 50 ... 75 ohms.