DIY telescopic antenna repair. Antenna repair

Usually, DIY antenna repair is more about tuning. Radio amateurs are aware of the parameters that need to be adjusted. This is especially true for home-made devices for receiving a signal. For example, the ideal SWR is equal to one, in the descriptions of the self-assembly of the antenna you will see either an a priori calculation of this parameter, or instructions on how to adjust the dimensions and circuit using the SWR meter. This approach will allow the signal loss to be reduced to the first amplifier stage, therefore, the sensitivity of the receiving device (the range of the transmitter) increases. In practice, this means improving the quality and distance of confident capture of stations and walkie-talkies. This is important for the terrestrial antenna.

Soldering

Soldering is an optional step today. Shrink wrap will help to restore the integrity of the telescopic antenna (without the possibility of folding). Take the trouble to ensure reliable contact at the fracture site. To solder steel, buy a special acid for surface cleaning.

Tuning antennas

The phrases repairing a collective antenna or repairing antennas with your own hands sound funny. These are passive devices that do not require professional maintenance. If a child breaks, repair the telescopic antenna, tin the ends, solder. Detailed instructions are not required, any man (boy) can repair the antenna on his own.

Regardless of the incoming signal, the wave is characterized by frequency and polarization. Two aspects determine the design of the antenna. The power of the incoming signal also makes adjustments. Depending on the data, the question of the required gain is decided, whether to obtain due to directional properties or an amplifier stage.

Let's make a reservation that the sensitivity of the receiving device is the minimum signal level caught by the equipment. Of course, the lower the field strength at which a broadcast is heard with confidence, the better. The sensitivity depends on the signal loss to the first amplifier. After that, the attenuation is not so critical. For this reason, the feeder between the antenna and the receiver is tried to be made as short as possible. For the sounded purposes, the VSWR is minimized. In this case, the power goes into the feeder. The concept of matching is known, the term is closely related to the mentioned parameter. Ideally, the characteristic impedance of the devices in the circuit is the same. The antenna is manufactured in 75 Ohm, the cable is 75 Ohm and the receiver is 75 Ohm. If a link is out of line, matching devices are used. Quarter-wave transformers, U-loops, line segments.

How to increase the signal level. Take the trouble to aim the antenna correctly. The dish should face the satellite. It's harder on earth. There is a concept - a re-reflected signal. It is not a fact that the direction to the station will give a maximum of confident reception. The main power can come from an arbitrary azimuth and elevation angle, it is worth tormenting in search of the right solution. Outsiders to the radio are surprised why the receiver picks up better in the corner of the room than at the window, in reality it is simple - in the area of the window sill there are no trajectories of a favorable alignment of the superposition of fields. In simple terms, this means that the waves fold in incredible ways, giving an amazing picture.

For a beginner, this is not clear, let us explain: if at a given point in space two strong signals add up in antiphase, you get zero. A pair of weak beams can have a much better effect if the wave is coherent. If a person could see radio waves, the room would be dotted with gaps and bright places, like a playing wave of the sea reflected on a rock. The picture will not be permanent at all. Any cloud, rain, wind will affect the result. For this reason, it is far from always enough to aim and tune the antenna once for constant reliable reception.

Features of setting up satellite dishes

It's easier with satellites. Tricolor TV antennas aim once and for all. The bracket is equipped with several sets of bolts for the indicated purposes. It is enough to tighten it properly to ensure the right direction for years. Note that the broadcasting satellites are geostationary. From the surface of the Earth, they seem to be motionless. This is possible when the spacecraft makes exactly one orbit in 24 hours. You will get the indicated alignment by moving the satellites above the equator at an altitude of 20,000 km. The exact numbers are not very important, the main thing is to understand that the broadcasting devices hang over the equator at the same height, there is no identical azimuth for two different satellites.

A galaxy of spacecraft writes an arc in the sky with a long-calculated shape. Therefore, it becomes possible to catch a lot of programs on the plate. To achieve the goal, an arc is set with hung radiators. As a result of the laws of reflection, each converter receives one satellite. It is important to properly maintain the polarization (horizontal or vertical, in Russia there is also a circular one).

Many have understood where the conversation is going. There is a depolarizing plate inside the converter. Take the trouble to put it a little differently in order to change the parameter in the required direction. To receive the right polarization, the slope is 45 degrees to the side with respect to the vertical axis of symmetry of the irradiator, in the case of the left polarization, the offset is in the opposite direction. The question arises, why fence a vegetable garden. There are several answers here. Some experts believe that in the Russian Federation circular polarization is accepted as a tribute to the technologies of the USSR. In the past, it was customary to build non-geostationary spy satellites. Then, with linear polarization, reception on the ground is difficult, the plane sometimes tilts at an unpredictable angle. The application of the circular solved the indicated difficulties - all that remained was to aim the saucer at the trajectory of the spacecraft.

The plane of inclination of linear polarization is influenced by at least two additional factors:

The position of the satellite in the sky. It has already been said that the spacecraft are scattered in an arc. The satellites on the horizon are slightly tilted. It is necessary to more accurately aim the feed relative to the plate and tilt it as needed.
The Faraday effect is known: an electromagnetic wave rotates in a constant field of the Earth. This leads to a tilt of the plane of polarization, it is difficult to calculate the choice in advance. We'll have to experimentally turn the converter while tuning the satellite dish.

Trays vary in diameter. The focal length is related to the aperture angle of the feed, otherwise the reception becomes uncertain or is eliminated. A large opening combined with a small plate looks silly. In theory, the feeds should be placed in the focal plane. Here rays that come in parallel from a certain direction intersect. To achieve the result, special guides are sold where the converters are strung.

When repairing the Tricolor antenna and tuning, it is useful to use special devices. For example, Satellite Finder. The device turns on between the receiver and the antenna, beeps more piercingly as the signal level rises, when the master rotates the cymbal to the sides. First, the correct position of the antenna is achieved, then it is the turn to adjust the position of the feeds. This is where the knowledge outlined in the article will come in handy. Experimentally find the correct slope. The work is easier to do together, focusing on the satellite search program built into the receiver. The process is tedious and long, but rewarding.

Let's add about the ranges. C usually uses linear polarization, while Ku uses linear polarization. We have already talked about the Faraday effect, it is less pronounced at high frequencies. Ku broadcasts are predominantly linear. The depolarizer converts circular polarization to linear, but does roughly the same with linear polarization. For the correct setting, it is important to know:

The depolarizing plate is made of dielectric material.
Thickness, length, shape affect the reception quality.

The depolarizer contains steel pins that are visible when looking into the feed. There are two causative agents - vertical and horizontal.
In order for the converter to simultaneously receive the C and Ku bands, you need to buy a combined model. It will not be possible to receive reception on a simple irradiator.

Combined antenna converters will begin to lose part of the signal, the same is observed if two are placed side by side, one per band. There is no ideal solution, it is possible to fight:

A combined antenna feed without a plate is taken.
A tee is cut into the feeder, feeding separately two receivers (one per band) and two TVs.
According to the testimony of the equipment, the position of the antenna is located, where the signal is maximum.
The selection of the material, size and position of the depolarizing plate begins. It is not a fact that the factory one will be the best option, do not forget to tilt the irradiator, as described above.

As a result, there is a chance to find a position in which both ranges appear best. This means that the repair of the TV antenna ended with a positive result.

Car antennas have long been considered an everyday accessory, but this technique often breaks down, often it is simply stolen. Factory models are quite expensive, and it is often difficult to find a suitable one. However, you can make auto antennas for the radio with your own hands. The process is simple, but it requires some professional skills.

The range of devices in stores is very large. By purpose, this technique is divided into the following types:

Active antennas for the car radio, when the signal is received together with the built-in amplifier. They are considered to be very powerful. Great for long distance signal pickup.
Passive models. They work without amplifiers. They are considered simpler, it is much easier to make them yourself. Such devices are just recommended to be installed if car radios are used only in the vicinity of the city.

Antennas are also classified according to the method of installation. Distinguish between internal and external antennas:

Internal. They are installed in car interiors. This installation method is suitable for active models.
External. They are located outside the car bodies. This installation is more suitable for passive devices. At the same time, the low power of the equipment is somehow compensated.

To make an antenna for a car radio with your own hands, you need to take into account the principles of the signal catcher, determine the length of the device, its location, the degree of complexity of the entire structure.

Conventional antennas for automobiles are quarter-wave vibrators that are grounded to car bodies. Such devices can only be mounted vertically, and reach 2.5 m in length. For antennas of standard car radios, these parameters are considered redundant.

That is why, to replace obsolete oversized devices, they use independently made external antennas for car radios. To hear stable radio signals in the popular range, it is enough to use pin devices with a length of 10 to 20 cm.

In addition to significant cost savings, there are a number of other advantages to using this technique. The following advantages are distinguished:

The self-made design can be tailored to completely different car models.
There will be no problem with the installation height for receiving radio signals.
Installing a homemade device is much easier than factory counterparts.
It is possible to improve the quality of signal reception with proper installation, as opposed to using commercial antennas.

It is worth noting that you can start designing yourself if you have the skills to work with electrical engineering, otherwise it is better to use the services of professionals or use store counterparts.

You can make with your own hands both inactive and active (with an amplifier) devices. The production technology consists of several stages:

preparation of the necessary tools;
direct assembly;
attachments to the machine body;
connections.

Assembling different types of antennas for a radio tape recorder with your own hands differs significantly even in the selection of the necessary tools.

Passive antennas without an amplifier are considered to be quite simple in design. To create such a device, you will need:

copper wire (diameter from 1.5-2 mm);
high quality nut;
good file;
screwdriver;
thermal glue (can be replaced with a heat shrink tube);
screw (diameter M5);
lock-nut.

The assembly is carried out in stages. For this:

To give an aesthetic appearance to the installation, a film is glued onto it, treated with a primer, and painted. The passive device is ready.

Creating an active fixture view

A feature of this technique is the presence of equipment that enhances the reception of signals. When creating internal active installations, frame structures are used. This requires the following tools:

copper wire, always with insulation (diameter - 2 mm);
home amplifier (a television device will do);
high quality soldering iron;
a connector that is suitable for a radio;
good wire cutters;
glue.

An amplifier enclosure designed for a conventional home antenna is often used as the basic basis for a device. A wire is soldered to it, which, in turn, will be connected to the radio tape recorder. This is necessary in order for the amplifier to receive and transmit signals.

An antenna plug is connected to the socket, a connector is mounted on the other end of the wire. The power cable for the amplifier in car radios is considered a control cable, it is colored blue.

An active type receiver is mounted on the roof of the car so that signals are well received. For this, two holes are drilled in the body - mounting and auxiliary. The antenna wire is laid along the perimeter of the driver's door, fixing it with glue. After installation on the roof of the car, fix the (side) cable in the rack, carefully connect it to the car radio.

Features of installation and connection

Traditionally, active types of antennas for radio tape recorders are installed on the windshields in the upper right corners or behind the rear-view mirrors. Passive installations for receiving signals are placed on car bodies, usually mounted on roofs.

Any antenna is mounted only on a clean surface. For installation, use glue or masking tape, bolts, nuts, locknuts for grounding, a drill suitable for the size of the diameter of the antenna wire. The mounting place must be degreased with a special cleaner.

Fix the devices with glue or masking tape. After installation, wires are laid from the antenna to the radio tape recorder. This is done either around the perimeter of car doors or windows, or directly around the cabin through special holes.

An ordinary car antenna has three wires:

Most often, the second wire is combined with the third, connecting the power supply, activating the contact function, the antenna begins to receive a signal.

It is important to choose the right location for the antenna. The car body can be both a kind of indicator of improved signal reception quality and a hindrance. The best place to mount is in the center of the roof.

There should be no foreign objects made of metal near the trap. Combined antennas for receiving various communication signals are best purchased ready-made.

The installation must be protected as much as possible from the effects of the external environment so that oxidation of the contacts does not occur, the parts of the entire structure do not corrode.

An antenna made with your own hands is an effective way to save money, improve the quality of signal reception, and the possibility of technical improvement of the radio in your own car.

I already wrote about the repair of antennas once, it was about the restoration of the antenna tip. But there are worse cases when this tip has nothing to cling to, that is, there are no whole antenna links. In fact, they may say that here's another problem, why repair the antenna, when you can buy a new one and replace the defective one.
Well, firstly, try to find these antennas first, for some reason I don't see them on sale at all.
Secondly, if you find it, then the fastest way it will be a Chinese remake with thin-walled tubes, breaking which a couple of trifles, pushed and pushed in incorrectly, and it broke.
Thirdly, even if you buy an antenna, it will be fastest with short links, but many old radios were equipped with antennas with very long links. Of course, you can move the short links apart, but if you think so, then you can allow the installation of half of the television horns or even screw the wire altogether. But I prefer to have an antenna as close to my own as possible.
Well, I got caught for repairs Sanyo, he originally had a long three-link antenna, the third, thinnest link was broken off under the very spine, and the spine itself was hidden in the depths of the middle link.

In general, the third link should have been extended to such a distance, and the second should protrude in the folded state just a couple of millimeters from the thickest link. But in this case, the antenna will not reach the stop and therefore will dangle.

When I change a broken antenna to a working one, I don't throw away the old one. Sometimes she may be needed as a donor.

I have selected a tube of a suitable diameter, which will serve as the third link in the repaired antenna. However, in spite of the fact that the tube fits perfectly into the antenna from the outside, it cannot be installed in the antenna so that it does not jump out later when unfolding, so you cannot do without completely disassembling the antenna.
To do this, you first need to separate the shank. The best option for this is to cut the pipe along the ring farthest from the shank. You will not be able to flare, do not waste your time.

Unfortunately, the thickest link after that will be 5-6 mm shorter, you will have to put up with this sacrifice. A piece of tube will remain on the shank, which will have to be removed.

The easiest way to clean the shank is with a pair of wire cutters, holding it by the flat part with pliers.

Sometimes the flat part of the shank is bent. It should be straightened with caution, because you can break it off at once. It's such a brittle metal. If the bend is not very strong, then it is better not to touch it.

Use a thin screwdriver or thin knitting needle to push the thinner tube out of the thicker tube, be careful not to lose the brass spacers to prevent the antenna links from popping out. They will still be useful to you during assembly.

Be sure to push out the remnants of the broken one from the last whole link, firstly, this piece will interfere with installing a new link, and secondly, you will need its brass gaskets if you do not have extra ones in stock.

The assembly of the antenna takes place in reverse order, starting from the thinnest link. Install brass gaskets so that their protrusions fit into the holes on the sides of the tube.

In general, the task is not difficult, especially for a three-link antenna. There are short ladders, with those more trouble.

Now you need to insert the shank and secure it. You can roll the shank in the tube, but at home, the roll can be a little aesthetically pleasing. What will you seal it with, except with wire cutters? In addition, the antenna can also dangle on the shank if you have not rolled it up enough.
Some people, I've been told, stick it on. For me, this is wrong, glue is a dielectric and it is not a fact that somewhere you will necessarily have a touch through the metal, an example of cold rations, when the wire is surrounded on all sides by solder and nevertheless there is no contact between them, more than often found.
I prefer to solder the shank. To do this, I clean a few points on it, and slightly service it.

Using a flux, I serve the inside of the antenna tube.

Then I warm up the shank with a pallet and insert it into the inside of the tube. The connection is more than reliable.

When I change a broken antenna to a working one, I don't throw away the old one. Sometimes she may be needed as a donor.

Unfortunately, the thickest link after that will be 5-6 mm shorter, you will have to put up with this sacrifice. A piece of tube will remain on the shank, which will have to be removed.

The easiest way to clean the shank is with a pair of wire cutters, holding it by the flat part with pliers.

The assembly of the antenna takes place in reverse order, starting from the thinnest link. Install brass gaskets so that their protrusions fit into the holes on the sides of the tube.

In general, the task is not difficult, especially for a three-link antenna. There are short ladders, with those more trouble.

Using a flux, I serve the inside of the antenna tube.

Then I warm up the shank with a pallet and insert it into the inside of the tube. The connection is more than reliable.

Building a simple FM radio antenna with your own hands is a great way to enhance the quality of the received radio signal. First, let's figure out how to replace the standard antenna with a dipole one.

Most modern radios are equipped with sockets for connecting conventional antennas - both built-in and external telescopic. You can make a high-quality radio antenna without resorting to great costs, just a single visit to an ordinary hardware store is enough, and, of course, you need to know what you can make a radio antenna from.

Materials for work

Ceramic insulators and elements for their connection. They are necessary in order to prevent the antenna cable from closing to adjacent surfaces. These devices can be purchased at any radio market or found in some abandoned building.
Thin steel wire for connecting insulators.
Roller blocks required to secure the external radio antenna in a taut position.
Antenna plug.
Two-position switch, designed to protect against thunderstorms.
A coil of copper wire with a diameter of 1.5 to 2 millimeters. You can, of course, use steel wire, but copper is much more malleable and more convenient.

Antenna type

Now let's decide on the type of radio antenna to be assembled. There are three main types of antennas for an FM receiver, suitable for DIY assembly, the diagrams of each of them are shown below:

Linear antenna
Traveling surface wave antenna
Aperture antenna, that is, a swing antenna.

Instructions on how to make an antenna

Installation of any horizontal type antenna begins with the choice of a support, to which we will subsequently attach the insulators. The first support should be on the roof of the house, and for the second, you can choose a tree with the appropriate height. We attach the insulators to the posts using steel cables.

The outer part of the antenna should not be pulled too tight, as when the air temperature drops, the wire shrinks and can break.

Roller blocks are used to reduce vibration. To use them, you need to fix a small weight on the opposite end of the wire by connecting it to the antenna.

The receiving element of the future antenna should be a single piece of a single material. If a whole piece of wire is not available, then you can combine several elements from a single material by stripping and soldering with tin solder.

The mount for the vertical antenna receiving element is a stand that excludes the change in the position of the wire during strong winds.

If there is very little space for placing the antenna, then the design can be modified: we cut the wire into several pieces and connect the end of each of them with molten tin to the cable. The soldering point must be reliably insulated. Below is a photo of a homemade antenna suitable for FM radio.

The best replacement for the trap would be a homemade indoor antenna. In this case, the insulators are mounted inside the room, while, as close as possible to the ceiling (this is recommended to improve signal reception), and the wire is pulled horizontally or rolled in the form of a spiral.

Manufacturing of a resonant frame antenna

Such antennas are often used by mechanics to receive shortwave signals. For directional signal reception, the antenna is simply turned in the desired direction. Such designs allow receiving radio signals much clearer thanks to the magnetic elements.

So how do you make a similar fm radio antenna at home? First you need to find an aluminum hoop with a diameter of 77 centimeters and a cross section of 17 millimeters, which can be obtained from any sporting goods store.

If you still can't find the hoop, you can use plumbing pipes made of plastic and metal, or a copper tube with a diameter of 1.6 cm.

The assembly sequence of such a design is extremely simple:

We solder the central core, the winding and a piece of coaxial cable to the contacts of the variable capacitor.
The other end of the cable, the central core and the winding are soldered to the aluminum hoop. You can also use a car clamp, which must first be cleaned at the pairing point.
The dimensions of the structural elements are calculated so that the length of the frame, in this case the hoop, is five times the length of the tie loop.
Remove the insulation layer from one end of the cable and from the central core by about one centimeter.
We remove the insulation in the middle of the cable, having previously canceled from it 5 millimeters in each direction. Then we remove the cable sheath, since the above actions will lead to its rupture.
We adjust the range of our radio receiver so that the structure has a resonance of 5-22 MHz. With a different value of the capacitance of the capacitor, the parameters of the receiving-transmitting device can be changed.
The frame parameters can be changed depending on the desired receive range. So, for the reception of low frequencies, the diameter of the hoop is chosen within one - one and a half meters, and for the reception of high frequencies - 70 centimeters.

These simple rules will allow you to build a device that can work in different bands.

conclusions

We have presented to your attention the simplest and most popular ideas and drawings of antennas for fm radio, suitable for hand-made assembly. Most of these structures are extremely simple in both installation and operation, and will allow you to easily solve many everyday tasks.