What Must todo

This FM wireless microphone is easy to build and has a useful range of transmission (over 300 meters outdoors). Despite its small number of components and an operating voltage of 3V to easily penetrate over three floors of an apartment building. You can tune anywhere on the FM band (87-108MHz) and its transmissions can be picked up at any point of view of the FM receiver.

The coil (L1) should be approximately 3 mm in diameter, 5 turns 0.61 mm copper wire. You can vary the Tx frequency by simply adjusting the distance between the coils. The antenna should be a half wavelength or quarter-time (100 MHz, 150 cm or 75 cm).

Parts list:

• T1,T2,T3: 2N2222 transistor
• R1: 10k 5%
• R2: 33k lin.
• R3: 12k 5%
• R4: 5.6k 5%
• R5: 2.2k 5%
• R6,R8: 47k 5%
• R7: 470 ohms 5%
• R9: 180 ohms 5%
• C1,C2: 47nF
• C3: 1nF
• C4: 33pF
• C5: 5.6pF
• C6: 8.2pF
• C7: 10nf
• L1: 3mm in diameter with 5 turns 0.61 mm copper wire
• K1: SPDT toggle switch
• Other parts: 2 AA battery holder, Electret microphone, antenna wire

This post is for an antenna loading coil telex broadcast on freq. let us buy Simply put wrote specifically for the antenna loading coil at the store component telex, because loading the settings is still for freq 2 meter, we must slightly modify it. The trick is easy, just replace the existing loops. original about 5 convolution convolution continues we replace 10 with 1 to 1.5 mm diameter wire. for more details see the pictures. may be useful ..