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Overview
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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. |
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VCO
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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. |
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DC-DC converter
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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) |
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PLL
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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. |
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Microcontroller
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The microcontroller will probably
be an 8-pin flash-reprogrammable PIC mcu running at low power and freq. |
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