TX-300 300mW FM Transmitter

Here it is a brand new TX300 FM transmitter. The amplifier has exactly the same architecture as TX500 with the difference that TX300 has only one stage variable VHF amplifier. It is a cute schematic that was made for all of you who wanted something even simpler than TX500 and with not as many necessary parts. It is a perfect circuit for transmitting your music around the house and yard. Interesting feature is a gain control P1 that lets you adjust your desired output power and distance. If in case you want to replace Q2 with more powerful transmitter like 2n4427 or 2n3866 you will have to replace P1 with a resistor due to the higher necessary current. For much more info go to TX500's page.

Coils

TX300 uses exactly the same coils as TX500 with the difference that their names are different so here's the conversion:
L1 - same as L1 in TX500
L2 - same as L2 in - || -
L3 - same as L3 in - || -
L4 - same as L7 in - || -
L5 - same as L8 in - || -

Here's the whole section how to make these coils in step by step procedure (remember that the names are different).

Where to get the Parts

If you are building the above FM Transmitter and have trouble finding components such as variable coils, BC549 transistors or ferrite beads we are distributing these components in our Electronic Store.

Build your own LC Meter and start making your own coils and inductors. This LC Meter allows to measure incredibly small inductances making it perfect tool for making all types of RF coils. LC Meter can measure inductances starting from 10nH - 1000nH, 1uH - 1000uH, 1mH - 100mH and capacitances from 0.1pF up to 900nF. The circuit includes an auto ranging and "Zero Out" function to make sure the readings are as accurate as possible ... [more]