FM Transmitter Lovers

5Watt FM Transmitter (MRF237)

By SZ123 • 2009-07-21 • Category: FM Transmitter DiyRSS 2.0 Trackback

CAUTION! This transmitter is illegal in the Netherlands and in many other countries. The creator of this site is not responsible for the consequences of using this channel. He is also not liable for fines or seizure of equipment.
The construction of this station is very simple and very suitable for beginners in the HF technique. When the building on the 'air' coils are not able to "see". This can be done by the circuit in an enclosure can be mounted or schotjes between the oscillator and amplifier stages to place. These can be printed and cans. In order to make the circuit insensitive to vibration, it is wise to rinse with candle wax to pouring.
Do you actually have very high power of 5W is too high to start with than you can the last amplifier stage road leave. Close in this case the antenna to the spot where the base of T3 is.
If the circuit is built on a board here are some tips:
Use a board with a solid copper plane and milling or cutting pieces of copper from here so that square (or rectangular) areas emerged from the large copper plane used? Soleerd.
Cut the wires as short as possible and mount the component as close as possible in print.
Do not use a switching power supply, power supplies in these coils are the HF broadcast signal capture. This is completely wrong.
Rule by adjusting the circuit first coarse frequency with C16. After fine tuning is possible with R3.

Details of the coils:
L1, L2, L9, L10, L11 = coil windings of 6 by 6 hole ferrite bead.
L5, L6, L7 = 5 coil windings, pop. 6mm diameter, 1mm wire: L6 a winding mass from a branch.
L3, L4 = 4 coil windings, pop. 5mm diameter, 1mm thread.
L8 = 1 coil winding, pop. 5mm diameter, 1mm thread.
If you have the circuit with a PLL may also want to send. Remove R3 and R8 then. Connect the output of the PLL filter and between R7, C7, C8 to a resistance of 390k.
Again CAUTION! for the Ministry V & W division telekom (RDR). You are solely responsible for the consequences of using this channel. The creator of this site is not responsible for any damage or whatever.
This transmitter is designed on the basis of many FM transmitter diagrams on the internet can be found.

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One Response »

  1. hi, thanks for the schematics of the 5 watt fm trnasmitter. could be more help if you could give the values of the parts. tnx


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