Technical Projects









The hardware for the RF jammer consists of an voltage controlled oscillator (VCO) block, a DC-DC converter for biasing the VCO, a phase-locked loop (PLL) for feedback control of the VCO and a microcontroller that digitally controls the PLL to vary the output frquency. There is also an optional output RF gain stage. A PCB must be made but all parts can be easily purchased from digikey or another electronics component supplier.
Total power requirements should be about 100mA from a 3.7V (LiIon) battery during operation, with that draw only occuring once a second for 1/10th of a second in a 'scattered burst' mode.

For the first hardware revision I have used a pre-manufactured VCO from Mini-Circuits at a cost of $22/each. For the next revisions I intend to use one of my own design that can be easily biased by changing a capacitor, to cover the frequency ranges desired (ie PCS, GSM900, 802.11, etc). The VCO will be a slight modification of a low-cost wideband CATV design from Alpha/Skyworks semiconductors.  
DC-DC converter

This component has not been specified, but will probably be a low-power boost/step-up that converts 6VDC to 30VDC at a mA output. (The TK11818 looks like a good bet, but hasnt been found yet)  

The current choice of PLL is the LM2324 or LM2353 family of frequency-synths, digitally controllable. The outlay for PLL/uC simplifies design and reduces a dependance on expensive SMT trim-pots.  

The microcontroller will probably be an 8-pin flash-reprogrammable PIC mcu running at low power and freq.