1.5 Volt Tracking Transmitter

The current draw for this tracker is 3.7mA, so the 1.5V button cell will last a while.this version was tuned to 87.6MHz and worked as expected on only 1.5 volts. When your circuit is working you should see the LED flash quite fast.
part list :
C1 = 100uF (Electrolytic capacitor)
C2 = 0.01uF (Disc capacitor)
C3 = 4 to 40 (pF trimmer capacitor)
C4 = 4.7 pF (Disc capacitor)
L1 = 0.1 uH
IC1 = LM3909 LED flasher
LED1 = red LED
Q1 = 2N3904 silicon transistor
R1 = 10K
Antenna = 10 to 20 inches of hookup wire

Source : http://www.uoguelph.ca/~antoon/circ/tx15trak.htm