Showing posts with label transmitter. Show all posts
Showing posts with label transmitter. Show all posts
Saturday, October 18, 2014
FM transmitter schematic
fm transmitter schematic, PC board pattern, and parts placement for a low powered FM transmitter. The range of the transmitter when running at 9V is about 300 feet. Running it from 12V increases the range to about 400 feet. This transmitter should not be used as a room or telephone bug. parts
Notes
L1 and L2 are 5 turns of 28 AWG enamel coated magnet wire wound with a inside diameter of about 4mm. The inside of a ballpoint pen works well (the plastic tube that holds the ink). Remove the form after winding then install the coil on the circuit board, being careful not to bend it.
C5 is used for tuning. This transmitter operates on the normal broadcast frequencies (88-108MHz).
Q1 and Q2 can also be 2N3904 or something similar.
You can use 1/4 W resistors mounted vertically instead of 1/8 W resistors.
You may want to bypass the battery with a .01uf capacitor.
An antenna may not be required for operation.
Thursday, August 28, 2014
Small Circuit Multiband Radio Transmitter CW
This is a Small Circuit Multiband Radio -Transmitter CW for who wants to learn more about radiofrequency, mainly operating principle from radios transceivers multiband, That schema consists of a frequency oscillator RF, which is the main component us transmitters and radio receivers.
He oscillates for high frequency, he is called variable frequency oscillator or VFO, their frequency may vary of 5.2 MHz to 15 MHz, depending the coil chosen and signal can be received in the band shortwave by any receiver radio.In S1 is used a switch type bell, but can-if use a handler CW, these used by radio amateurs. How antenna should-if use a the type dipole from 1/4 wave.
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