To make a nice operating mobile phone jammer you will need some details to combine. Among them are:

Voltage Controlled Oscillator (VCO)

Tuning Circuit (to select desirable frequency to be jammed)

Noise Source (commonly built-in in Tuning Circuit)

RF Amplification Unit (so-called “gain stage”)

Transmitting Antenna

VCO is the most important among other parts. It is like a heart of your jammer. VCO produces RF signal which will interact with the blocked device. Firstly you must select frequencies which will be used in your signal blocking device. Here is the list of standards:

AMPS (800MHz)

PCS (800MHz, 1800MHz and 1900MHz)

GSM (850MHz and 1900MHz in America, 900MHz and 1800MHz in Europe)

GPS (1227MHz military and 1575MHz civil)

Wi-Fi/Bluetooth (2400MHz – 2500MHz)

RFID (also known as UHF/VHF, 14MHz – 400MHz, 800MHz and 2450MHz)

It is also important to think about its size because you might wish to create a desktop mobile phone jammer or a portable GPS mobile phone jammer.