DIY miniature antenna booster

When using a good antenna amplifier for the UHF range, programs can be received from television stations which, without a preamplifier, only deliver a very noisy "snow field". The antenna amplifier described here is very simple. It can because of its small dimensions directly in the junction box of Antenna to be accommodated. The small coupling capacitance in the input protects the transistor from overvoltages that may occur during a thunderstorm. The built-in resonant circuit in the collector branch can be tuned to any frequency between 470 and 790 MHz.

Because of the extremely low retroactive effect  of this transistor is the amplifier stronger very stable, even with poor matching of the input and output. The bandwidth of the circuit is about 15 to 40 MHz.

reference : Elektor Electronics

How to create a simple circuit that makes an LED blinking continuously ?

How to create a simple circuit that makes an LED blinking continuously ?  - The special thing about this circuit is that both transistors are either conducting or both are blocking. As long as the lamps are not lit, only small currents flow, that benefits the battery. A further advantage of this circuit is that only a single capacitor determines the flashing frequency.the benefits of this circuit can be used for tower lights or tower antennas.

Reference : Elektor Electronics

How do I make a mini walkie-talkie?

How do I make a mini walkie-talkie? - The walkie-talkie, a portable two-way radio, consists of three blocks, namely receiver, transmitter and modulator (amplifier). The former is a super regenerative  receiver (Figure 1). Using this circuit, gains of more than 10000 times can be achieved. The output voltage is over 20 mV. In the receiving state, the signal from  the receiver is fed to the AF amplifier.
The DC-coupled amplifier (Figure 2) has an amplification factor of 500 . When using a 150 L> speaker in the final stage, you get about 70 mW output power, which is also suitable for playing a walkie-talkie enough. During transmission, the loudspeaker is at the input of the amplifier, so it works as a microphone. Because of the high amplification of the circuit, which 
now works as a modulator, a sufficient degree of modulation is obtained when speaking from a normal distance to the microphone (loudspeaker). The output signal is  now sent to the transmitter.
The transmitter (Figure 3) is a quartz-controlled oscillator with an oscillating frequency of 27.125 MHz. The quartz ensures an extremely constant frequency. 
The LF signal is superimposed on the HF carrier frequency via the collector.
If there are no obstacles to the If the carrier frequency is between the interlocutors, you get a range of about 1 kilometre. In residential areas, this is a few hundred meters.
During assembly, the receiver and amplifier can be placed in one housing. It is important to ensure that there is a short distance between the two; shielding 
by means of a copper plate is to be provided.
An antenna with a length of 70 cm should be used for a compact design and good matching. We expressly point out that for the operation of the transmitter, 
no matter how small, a permit must be obtained from the Government Authority.

Reference : https://archive.org/details/elektor197101v005/mode/2up?view=theater