Radio/RF/Wireless

Here we can deal with some RF circuits.You should remind that this circuit will not work if you haven't given much attention
1.It should be clear soldering
2.Values of the components should be accurate

We can start from a simple circuit..

1) FM BUGGER

This circuit can be used for transmitting voice through FM band width.It can be received through an common FM Receiver

 

The circuit only consist a few components.Build the circuit on a common PCB or

design a PCB as given below.Apply 3V to the transmitter .Try to tune a point on FM receiver of no sound .Touch on the mic .You can here the sound on receiver.You can use a telescopic antenna for the receiver.It will give you enough transmitting range

You can use any PNP transistor as your availability

Table 1. Tested transistors

			Type		C2	C3
c	e	b	BF606	best	33 pF	47 pF
c	b	e	BF324	best	33 pF	47 pF
e	b	c	2N3906	good	27 pF	33 pF
e	c	b	2SA854	good	22 pF	27 pF
c	b	e	BC307, BC558	poor low power

Components

R1	4,7 k Ohm
R2	330 Ohm
C1	1,5 nF, ceramic.
C2	33 pF, ceramic.
C3	47 pF, ceramic.
T1	BF324
Mic	Condenser Mic
L	6 turns on 5 mm diameter. 11,5 cm length wire 0.8 mm diam.

   PCB