This is exactly what the title of the question from reader Alexei sounded like. Although that certainly doesn't sound like a question. But still.
I continue to publish the questions that readers asked me. For new dear readers who came to my channel for the first time, I inform you that this is already 19 such publication.
Consider in this part 19 a question from Alexey:
May I ask you a simple amplifier circuit for a 5-12 volt digital set-top box. I have a passive decimeter indoor antenna, but there are always some interruptions. So usually the signal level is 86, and the quality is 100, but then it starts to "jump". If you really need an amplifier for TV quality more or less, please tell me. Simple, not complicated, with one or two transistors! Thank you in advance!
Although I do not consider myself a professional radio amateurs, at the same time it is sometimes my hobby, especially when it is connected with antennas. Therefore, I gave Alexey the following answer within the limits of my knowledge and qualifications:
Here is an example of the simplest "antenna signal" amplifier circuit, but I would not bet on such devices:
- VT1 - KT315;
- C1 = 1000 pF, C2 = 33 pF, C3 = 15 pF;
- R1 = 51 ohms, R2 = 10 k ohms, R3 = 15 k ohms, R4 = 1 k ohms.
The inductor L or the choke is wound on a ferrite ring with a permeability of 600 N. For the meter range, 300 turns of PEV wire with a cross section of 0.1 mm are needed.
At first, note that the simpler the amplifier circuit is, the less interference and noise it eliminates, all additional electrical circuits are not introduced for fun. Therefore, your desire to create something easy and affordable may not solve the problem at all, since the amplifier will be too weak.
Secondly, any amplifier will require additional tuning and, quite possibly, a selection of components for the circuit, which automatically necessitates the appropriate skills.
Thirdly, a ready-made amplifier for an antenna is an affordable device that is more profitable to buy than trying to make it yourself.
Also, do not forget that there are a number of factors that the antenna signal amplifier cannot eliminate. Whatever complexity and cost of the device you have collected, the result of your efforts can be reduced to zero.
These factors include:
- The appearance of a physical obstacle for the signal within the boundaries of continuous urban development, trees, etc .;
- In case of precipitation or other weather events;
- Switching on devices with powerful electromagnetic radiation that affect the signal;
- Attenuation of the signal due to the inclusion of a large number of receivers in one place;
- A change in the signal repeater circuit with natural removal of its source.
- Antenna and TV equipment mismatch.
P.S. Dear Readers! If you have your own version of the answer to this question, please write it in the comments. It will also be interesting for me to read it and, if necessary, discuss it.
P.S. Link to some past parts - Part 18, Part 17, Part 16, Part 15, Part 14.