SSB transmitter 3.5 MHz on four transistors.Power amplifier on IRF510

This is a simple radio transmitter with single-sideband modulation on short waves, in this case on 80 meters or on a frequency of 3.5 MHz. With its help, you can transmit sound over a distance of thousands of kilometers, as well as hear yourself on the WEB SDR receiver and check your signal. I received my signal on the WEB SDR receiver at a distance of 2500 kilometers. My antenna is a Fuchs antenna in the form of a wire about 40 meters long, dropped from a height of 10 floors. Such a long-range signal is explained by the high efficiency of this single-sideband modulation: compared to AM, the range gain is 4 or more times

The transmitter uses a phase suppression method for the carrier and one sideband. All this is implemented by a mixer assembled on four BAT85 Schottky diodes and two phase-shifting circuits. I chose the diodes only because of their close voltage drop. Coils L1L2 and L5L6 are wound on red ferrite rings of the T50-2, bought on Ali. Coil L1 contains 50 turns, and L2 - 20 turns of wire with a diameter of approximately

0.14 mm. Both coils are wound on one ring. Coil L5 contains 20 turns, and L6 - ten turns of wire with a diameter of 0.14 mm and are also wound on a ring. They should be wound like this: take three short wires and wind 10 turns with three wires. Then connect two windings of 10 turns together, this will be the tap in the middle of winding L5, and leave L6 with 10 turns. For the low-frequency modulator, I used a step-down transformer from a tape recorder. Winding 1 has a resistance of 14 ohms, winding 2 - 1800 ohms. You can also use a transformer with other winding resistances

The phase shift of 90 degrees in the high-frequency part is carried out by resistor

R4 and capacitor C5. Connect the oscilloscope to the terminal of winding L2 and

adjust the amplitude of this shift by selecting the resistance of resistor R4.

The phase shift of 90 degrees in the low-frequency part is carried out by resistor

R7 and capacitor C10. Also, select this shift with resistor R7 by applying

a 1000 Hz signal to the gate of transistor VT2 IRF630. That's all the main

setting. Set the best modulator operation with resistors R5 R6.

In the output stage, I did not use a P-filter, although of course it is necessary

to reduce harmonics. With resistor R15, you set the quiescent current

of the power amplifier transistor if510 and it also sets the

maximum current during transmission. With this resistor, you also regulate

the output power of the transmitter, and it is, as I was told, about

13 W. The current consumed by the transmitter with a power supply of 13 Volts is approximately

1.6 Amperes

The neon lamp glows when transmitting in time with the sound. I touch the lamp

to the antenna-wire after the matching device of my Fuchs antenna. How

to make it I will tell about it later, although I have already made a video about it

Here I am receiving my signal on a WEB SDR receiver at a distance of 2500 kilometers and I hear myself clearly