Instructions
The radio signal amplifier changes the hardware characteristics only when the device is in transmit mode. The amplifier will not affect the quality of signal reception from other respondents. Some manufacturers build in circuits that amplify the received signal, but along with the amplification of the useful signal, in this case there is also an amplification of interference.
When connecting the amplifier, insert it into the gap in the antenna cable, namely between the radio station and the external antenna. Connect the amplifier with thick wires to the power source. If the amplifier is installed in a car station, connect the wire to the “positive” terminal of the battery, protecting it with a fuse near the terminal. Select the “negative” wire of the same cross-section and minimum length.
A large cross-section of wires is required to ensure a possible voltage drop in the power wires, because the amplifier consumes a very large current when transmitting. A short negative wire limits the effect of resonance in power circuits. This wire must be securely fastened, since its break can sometimes lead to equipment failure.
Configure the antenna connected to the amplifier well and keep it in order. Pressing the switch button on the intercom while the antenna is disconnected or the cable is damaged may damage the amplifier.
Sources:
- Why do we need radio communications and radio stations?
- radio station power
To tune a radio station, you usually need to have a radio receiver, know its frequency, and turn the tuning knob for a few seconds. However, with the advent of the Internet, tuning a radio station has taken on a slightly different look.
Instructions
Open your browser and go to the site you are interested in. The vast majority of radio stations have their own websites on the network. On the main page of the site, click on the link “Live broadcast” or “Listen to broadcast”. When you click on the link, a new browser window will open in the form of a media player, in which you can adjust the volume, change the bitrate of the stream, or pause it. When tuning a radio station using this method, disable the pop-up blocker in , as it may prevent the media player window from opening.
Some radio stations broadcast primarily in , operating in such a way that they can be listened to using regular media players, provided there is a stable connection. To set up radio stations, find the link to the broadcast and open it using your media player. Please note that the link to the broadcast has the extension .m3u or .pls, like standard playlists. As a rule, the website of radio stations contains several links to broadcasts, which differ in the format or bitrate of their broadcast. Make a choice of format and bitrate based on the speed of your Internet connection, place the link to the broadcast on the clipboard (copy it), open the media player, click on the "Open URL" button, paste the link and click "Open". If desired, the link can be saved in the playlist list and opened at any time.
You can also set up a radio station on the Internet using special services designed for listening to radio stations live, as well as their archives. The most popular project of this kind is moskva.fm, where you can listen to any radio station broadcasting in Moscow. To configure the desired radio station, select it from the "Radio Stations" drop-down list on the main page and click on the "Listen to radio online" link.
Video on the topic
Walkie-talkies are popular among truckers and security guards, since people in these professions need to constantly maintain contact with each other. The use of mobile communications in such cases is not advisable due to the high cost of a minute of conversation. Using modern walkie-talkies, you can talk to each other without interruption for an unlimited amount of time.
Instructions
Most walkie-talkies from the world's leading manufacturers have a range of about a kilometer, which allows security guards to communicate with each other when protecting an object. Sooner or later, every person who uses a walkie-talkie has a desire to increase its range. There are several ways to realize this desire. For example, if you want to increase the range of the walkie-talkie, replace the conventional helical antenna with a special four-wave rod, which can be bought in almost every market.
You can also use a long piece of coaxial cable as an antenna, which can significantly amplify the signal. Then adjust the frequency of the walkie-talkie so that it sends the signal as far as possible.
The range of the antenna also depends on the power of the output path. Choose the optimal frequencies for signal transmission, keeping in mind that closer to the edges of the operating range, many of the characteristics of a long-distance radio, such as sensitivity and power, deteriorate significantly. That is why, as standard, the antenna is tuned to the middle of the frequency range. That is, if your walkie-talkie transmits a signal in the range from 136-174 MHz, then it will show the greatest range at a frequency of 155 MHz.
Use only well-charged batteries as power output varies depending on power supply. Therefore, if you are going to use the radio for a long time, always carry a spare battery with you. Also, if you need to increase the signal transmission range of your midland radio for a communication session, if possible, use elevated terrain.
A well-functioning walkie-talkie will allow you to keep in touch with your work colleague and, in the event of an unforeseen situation, quickly come to his aid. At the moment, the most popular manufacturers of walkie-talkies are Midland and Motorola. Each of these companies provides a wide range of various digital and electronic products from conventional walkie-talkies to multi-functional radio stations.
To obtain permission to use a radio station operating in the so-called civil band, no special license is required. Therefore, these types of devices can be improved if necessary, increasing the quality of communication and expanding the number of functions. If you want to increase the power of your radio, you will need a signal booster.
Avoid making antennas for radios for cars with your own hands for the simple reason that the equipment is difficult to set up later. Standard devices at the base contain a nut-like unit that allows the driver to adjust the device to the wave being used. For manual models the situation is different. An antenna for a walkie-talkie can be made with your own hands, but problems will arise for large enterprises purchasing frequencies. The state committee monitors the goods sold so that consumers avoid mutual interference. Railways do not intersect with shipyards. Sometimes industrialists need communication, everyone will start improving the equipment, we will find a situation: subscribers will hear each other. Working at different companies. Ask SCRF: they will give recommendations; perhaps it will be enough to demonstrate the modification in action to specialists to assess the impact on neighboring communication domains.
Communications and radio antennas
They have repeatedly said: in everyday life, linear and circular polarization are more often used, the latter mainly on satellites. Walkie-talkies are no exception. Horizontal polarization was taken away by television, leaving vertical polarization to radio broadcasting... walkie-talkies. Logical. When we hold the radio, the antenna is positioned vertically. The signal reflected by the terrain is visible, rotated at a fixed angle. Thanks to the effect, the dull military man demonstrates a “violation” of the laws of physics... Ideal reception is carried out by a vertically standing antenna. If you don't believe me, do the opposite!
Those who read reviews about homemade antennas will be amazed, but not surprised. Again, single-ended quarter-wave vibrators made from a piece of standard coaxial cable. Polarization, frequencies, why something has to change. They once said: you can install a television antenna made of cable vertically, pick up a radio, if you find one on the right wavelength...
Original radio antenna. Inside the knob there is a copper spiral, the tip of which is attached in the area of the top. With some walkie-talkies you can simply get to the curls, with others the problem is unsolvable. Why spiral?
According to the course of electrodynamics of radio wave propagation, the antenna radiates in the direction of the axis, the wave will be polarized in a circle, according to the direction of the curl. Only if the coil length is close to the wavelength. The context under consideration assumes a figure of half a meter or more, forget about proximity.
The MMANA program gives an idea of the radiation pattern. Well-wishers kindly put the radio antenna there (145 MHz), avoiding changing the parameters, looked at the field (opening the application):
- In vertical polarization, an even circle emerged in azimuth. It is clear that the human body will distort the diagram! Indeed, the spiral emits vertical polarization almost exactly. The level is - 3 dBi.
- The horizontal polarization shape resembles a figure eight, the level is much lower. If you hold the radio with a spiral antenna horizontally, the reception will deteriorate and will not reach zero.
At the angle of elevation with horizontal polarization a semicircle is formed, with vertical polarization a dip is formed along the axis. No useful upward signal is emitted. Let the man with the walkie-talkie climb the tree. And both hold the devices vertically, the reception will be due only to the horizontal component, as well as the reflected signal. These are the antennas that walkie-talkies use... It is not surprising that amateurs are tempted to change the design. Therefore, spirals are used.
In reality - and on the MMA file - the antenna consists of a spiral, the cap plays a significant role. The idea is clear. In real conditions, communication must be carried out in all directions; a quarter-wave vibrator is unable to meet the specified requirements. Why a quarter? The half-wave vibrator is longer. Dimensions matter. The spirals began to twist not from a full life. It's just that a long antenna for a walkie-talkie is too much of a luxury. It will pierce your pocket, you will be tortured to hold it with your hand, and windy weather will make you vomit. You have to make sacrifices. Let us recall that in terms of vertical polarization, the radiation pattern demonstrates the similarity of a torus, typically. The horizontal one adds something like a dumbbell (rough approximation), forming the missing corners and areas of space. The radiation pattern for reception and transmission is the same.
We will design walkie-talkies by removing unusual reception properties in all directions. The energy will rush towards the torus. The broadcast range will increase. If we re-equip both radios, we will get an additional gain at the cost of losing the final reception (transmission) from above and below. We remind you that the radiation patterns for reception and transmission are the same (identical).
Let's increase the range of the radio station by modifying the antenna
The conclusion is obvious: we want to increase the range - we saw the radiation pattern of the factory antenna - we need to direct the power to vertical polarization, to the torus. How to do it is clear, but one question looms on the horizon - the wave impedance of the radio antenna. Do you know the meaning? They talked about how to try it on! If the length of the feed line is a multiple of half the wavelength, the antenna impedance is transmitted to the output without change. We use the effect for measurement.
Various devices are used (RF generator). For those thinking about taking one, let’s say: the TV’s local oscillator is capable of producing a similar frequency, but setting it up is another matter. Let's talk separately. You will need a high-frequency voltmeter; a conventional one is unsuitable for measurement purposes. The device is measured by the voltage of the RF generator in a suspended state, the scale is calibrated to show 100%. Assemble a circuit connected in series:
- antennas;
- variable resistor.
Connect the generator to the circuit and measure the voltage of the resistor. Turn the adjustment until the arrow starts to show 50%. The resistance of the variable resistor becomes equal to the characteristic impedance of the antenna. It is necessary to take a non-inductive reactance (which does not have its own inductance). A homemade radio antenna should, if possible, replicate the electrical parameters of the factory one. The characteristic impedance is taken to be close to the original one. The measurement process is clear to readers.
The designer's choice is small: two global families. Cables with characteristic impedance 50, 75 Ohm. The first is used by communications, the second by television. The antenna of a portable radio is made from the one that is closer in nominal value to the measured value. The quarter-wave vibrator (without a spiral) has a resistance of 35 Ohms. It is difficult to predict the parameters of a purchased antenna. It is easier for practitioners to make two antennas for a walkie-talkie using different types of cable. Then test each one on the ground, assessing the nature of the changes.
Making a radio antenna
Let us briefly recall the process of making an antenna for a walkie-talkie. We considered digital television, WiFi, 3G. The audience of the VashTekhnik portal knows how to make an antenna for a walkie-talkie. Feel free to copy the methods. First you need to know the frequency. More precisely - better. The radios have several channels, the frequencies are registered in the passport. Select a channel by specifying the antenna dimensions.
Let the frequency be 435 MHz. We find the wavelength using the school formula, dividing the speed of light by the indicated value: 299792458 / 435000000 = 689 mm. To make a quarter-wave vibrator, you need to divide the number by another 4, we get - 172.25. The length of the antenna for the walkie-talkie will be 17 cm. Try to keep the millimeters more accurately. The screen does not need to be cleaned. It will be a receiving surface, the band will increase. If your hands are itchy, peel off the braid and leave the dielectric around the main core.
The old antenna is soldered off, a clamp is ready for the new one. All that remains is to fix it in place, enjoy the connection. The antenna for the walkie-talkie is made by hand. By the way, if you don’t want to remove the screen, solder it together with the core in one bundle when mounting it on the chip. If you consider expanding the range unnecessary, it’s better to remove the screen. The first and second options have advantages; the solid cable is stronger. It's better to leave it as is. The radio antenna will last longer. Make sure to glue on a nice cap-tip so that the copper stops oxidizing. We say goodbye until next time.
Copy factory designs. Enterprise radios break down. The adapters remain, the devices are thrown away. An invaluable chance for a radio amateur to prove himself. The antenna is covered with rubber, which can be easily peeled off. Or use an accessory from a broken product. The process of copying is not directly prohibited, except for products protected by patents. The case concerns the industrial production of products for the purpose of marketing, obtaining a fixed profit by performing the specified actions.
You can install a walkie-talkie in your car for various reasons. This could be a future car trip with friends on vacation, or even a passion for eavesdropping on other people's conversations in a car. But basically such a device is installed either by taxi drivers or truckers. Whatever the reason, a walkie-talkie antenna must be installed for the unit to operate properly.
This installation may seem simple only at first glance. In fact, there are several nuances that need to be taken into account when choosing, manufacturing and installing an antenna.
Types of external transceiver devices
There are two types of antennas for radios in a car:
- mortise:
- with magnetic base.
They are not fundamentally different. The main difference is that a built-in antenna for a walkie-talkie is stationary, while one with a magnetic base is removable; it can be removed or moved to another location.
Built-in antennas
From the name it is clear that they are attached in one place. Therefore, before installing this device, you need to carefully think about where to install it so that it does not interfere and the reception is good. You should also take into account the fact: the antenna for the radio in the car must be attached to the supporting body. If we neglect this postulate and install it, for example, on the hood or wing, that is, on a false mass, the efficiency of the device is lost by 30-40%. Some car enthusiasts are trying to improve this system and try to connect the mass with additional wires to the body. But still the desired effect cannot be achieved in this way. Although sometimes it works, it is extremely rare. As a rule, such an antenna for a walkie-talkie still works quite well for reception, but transmission using such a device is very bad.
Height will be an important factor when installing. The higher the device is installed, the more efficient its operation will be. For example, if you install an antenna in a car bumper, the transmission and reception range is reduced by half.
It is optimal to install the antenna in the middle of the roof. Some craftsmen convince that it can be installed with equal success on a bracket in the corner of the roof. But there are some points that need to be taken into account for expedient installation. If installing a radio is needed only for driving around the city, then the mounting option on a bracket is completely suitable. This will not affect the operation of the device due to the fact that a directional effect will not be created in the city due to additional reflections. If this device is installed for long trips along the highway, then installing an antenna for car radios in the corner of the roof will be impractical.
Installation of a mortise antenna
When installing the antenna in the roof, it is necessary to reinforce the joint with an additional metal plate. This is necessary primarily for greater connection strength.
The canvas itself and the extension coil should be as far as possible from all vertical metal planes that are located parallel to the base of the antenna. The minimum distance between them should be 50 cm. If this factor is neglected, the device will not work properly due to the high reactivity of the space. This nuance should be taken into account when installing antennas for car radios, including trucks.
Antennas with magnetic base
An antenna with a magnetic base, or, as it is popularly called, “magnetic”, can be used on any car. But there are several points that should be observed when installing it.
- For more efficient operation and correct settings, this device should also be installed on a supporting body.
- Under no circumstances should you change the length of the cable from the antenna. This will make it impossible to configure or will degrade the performance of the device.
- It is not recommended to roll the cable into a coil; this can also adversely affect the operation of the device. If the cable is longer than necessary, then you just need to carefully lay it around the cabin.
- The position of the antenna on the roof can be arbitrary. This type is not too demanding on location. But if there is a need to dismantle the device, then the next time you have to use it again, you should try to put the antenna in the same place.
DIY radio antenna
The simplest solution to this type of car upgrade is to buy an antenna. But it can also be made independently. To do this, you can follow the step-by-step instructions.
- Take a simple antenna-whip from a radio. All it needs is a foundation.
- Buy metal knitting needles with a diameter of 3-4 mm.
- Make an extension coil. It should be on a 10 mm mandrel. For it to work properly, you need to wind 44 turns of PEV 0.41 wire.
- Next, you should solder the ends of the coil to the brass bushings. This will ensure good contact and create additional structural strength.
- After this, you need to connect the spokes to the bushings at each end. It is important that both knitting needles are the same length.
- Next, the SWR meter is adjusted and the spokes and coil are adjusted.
- Then the antenna for car radios is directly installed.
- Open the ceiling.
- Unscrew the standard antenna, unscrew 2 screws, remove the active amplifier board and carefully unsolder it.
- Solder a 50 ohm coaxial cable into place. It is important to maintain the order of the veins, mass to mass.
- All connections should be sealed.
- Route the coaxial wire under the trim and rug and lead it to the radio.
- Attach the antenna in place.
If all steps of the algorithm were completed correctly, then the antenna for the walkie-talkie is made with your own hands. You can proceed to the next stage - configuration. But, according to experts, this is a rather complex and delicate process. This is due to many aspects: you need to be able to solder carefully, winding the coil is also not easy to do correctly. As a conclusion: a homemade device can only be made by a sufficiently trained amateur. Otherwise, you won’t get a good antenna for a walkie-talkie this way.
Antenna setup
If the antenna is installed correctly and correctly, then it only needs minor adjustments. But many car enthusiasts approach this process skeptically, thinking that this element of the communication system is not particularly important for the operation of the entire device. And they are deeply mistaken. Not only the reception signal, but also the operation of the device itself depends on how correctly the antenna for the radio is installed and the device is configured. Moreover, if you configure the radio incorrectly, you can damage not only the transistors of the output stage, but also ruin the device itself.
Step-by-step setup instructions
The radio antenna should be configured according to the following algorithm:
- For correct settings, you must have a device such as an SWR meter.
- The setup process must be done away from structures made of metal, concrete or wood. It is advisable that trees be placed no closer than 15-20 m.
- It is highly advisable to stop the car on a clean, level and dry surface.
- Antenna tuning may also be affected by other vehicles in the vicinity with radio antennas. Next, you need to install the SWR meter according to the instructions, that is, between the radio itself and the antenna. In this case, you cannot use an amplifier.
- Measurements with the device must be made on several different channels and at different points. It is advisable to carry out this procedure in different grids. This will allow you to see the real picture of the settings.
- The next step is very important: you should find the minimum SWR indicator, ideally the indicator should be equal to 1, it is advisable to write down where it is located. If it is located at a frequency below the specified one, this means that the antenna needs to be shortened. Accordingly, if it is higher, you need to lengthen it.
- The next step will be to shorten or lengthen the antenna, depending on the SWR readings of the device. Lengthening or shortening is the process of adding or, conversely, unwinding turns from the matching coil, and not shortening the antenna with wire cutters.
- After this, you again need to look at the SWR meter. Repeat the procedure until the desired result is achieved. Sometimes in some models it is not possible to achieve the ideal indicator, but this is not a big deal. If the indicator deviates, for example to 1.5, the losses will be equal to 5%. The walkie-talkie will work quite normally even with an indicator of 3. If an amplifier is built into the system, you need to take into account that the minimum indicator should not exceed 2.
If all steps of the algorithm are completed correctly, the antenna for the radio in the car will serve perfectly.
Walkie-talkies are widely used in different areas of life. So, they can serve as a baby monitor in cases where there is not enough money for a special device for communicating with a child.
You can use a walkie-talkie for security guards or tourism enthusiasts to communicate with companions, but it is not at all necessary to set aside a tidy sum to purchase this equipment, because you can create a walkie-talkie with your own hands at home. Apart from getting the final product, it is a very interesting and fun activity.
So, what do you need to make a walkie-talkie?
To create a walkie-talkie you will need the following items:
- 4 MP-42 transistors and 3 P416B transistors;
- Resistors. You will need a lot of them: two pieces each. 3K, 160K, 4.7K, one each – 22K, 36K, 100K, 120K, 270K, and six pcs. 6.8 K;
- Capacitors: two 10 MK 10 V, 3300, 1000, 100, 6, 5-20, 22, 10 and one 5 MK 10 V – 4; 0, 0, 47 MK.
- Telescopic antenna;
- Microphones and speakers;
- PCB boards - 2 pcs.
- Soldering iron;
- Socket;
- Wire cutters.
Almost all of the above is included in the special kit for radio amateurs JC986A. The further algorithm will be based on this set.
It is worth considering that creating your own walkie-talkie requires skills in working with a soldering iron and knowledge of how to determine the values of the elements.
Algorithm for creating a 50 MHz walkie-talkie
If you purchased a ready-made kit for creating a walkie-talkie with your own hands, you will need the following diagram. The names of the elements must be indicated on your board and diagram attached to the device for making a simple walkie-talkie.
First, start installing resistors and forming the electrodes of this element. Using a soldering iron, the resistor must be soldered to the board, and the protruding electrodes must be cut off with wire cutters. Carefully and carefully install all components, relying on the drawn outline on the board.
Start soldering the extension coil L 1, and then the capacitors. The next step is to solder the electrolytic capacitors. Since they have a certain polarity, it is necessary to properly fit the negative electrode into the board.
Using a soldering iron, attach the contour coil T 1 and the housing of the switching element S 1. Proceed to soldering the transistors, relying on the contour drawn on the board. You need to solder the cut parts of the electrodes remaining from step 1 to the board. Do this so that jumpers J 1 are formed.
Now you can check the quality of the work performed. If necessary, wipe the board with an alcohol solution, and later install the on/off button. Attach the finished board to the case using self-tapping screws.
Now you can install one of the main elements of the walkie-talkie - the antenna. On top of it there should be a small plastic cap, on the other side you need to solder a conductor that will connect the antenna to the board. Using the remaining pieces from the conductors, attach the S 2 switch to the board and check its functionality.
Place the terminals in the battery compartment. Now you need to solder the conductors responsible for the speaker and power supply system. If you have no doubt that you did everything correctly, connect a battery to the mechanism and check it. The finished device should make a hissing sound.
Assemble the second radio in the same way as the first. To ensure that the devices operate with the same cleanliness, remove one board from the fastener. We hope that these detailed instructions for creating a walkie-talkie with your own hands helped you understand the creation of this mechanism.
Debugging a homemade walkie-talkie
Even if you carefully followed the specified algorithm, the equipment may not work properly. In order to adjust the operation of the mechanism, use a variable resistor and wait for the maximum volume of the hiss of the radio.
Using a tuning core, change the inductance level until the signal is correct. After this, do not forget to return the original resistor and adjust its resistance.
If your voice emitted by the second walkie-talkie is severely distorted, select other resistors and start creating a wave meter, the diagram of which you can find on the Internet along with photos of homemade walkie-talkies. By the way, you need to check the quality of communication at a distance of 5, then 10 and 20 meters; it is better to do this in an open space.
We have described a step-by-step algorithm on how to make a walkie-talkie with your own hands. It should help you create your own mechanism to ensure communication with family or friends during a hike, tourism, fishing or contact with a child.
Remember to take precautions when operating this equipment to avoid the risk of injury such as burns or electric shock.
Photos of walkie-talkies with your own hands
