Homemade antenna for wearable radio stations. Experiments with LPD radio

So, as usually happens, someone from our club bought a new radio station and a rapid mass transition from the tired CB (CB) range to the more progressive UHF and VHF bands, I set a new task - to build a good dual-band antenna using improvised means. However, the result was much better than expected.

While all my colleagues at the club ST26, began to massively purchase the branded dual-band antenna "" (its parameters are with my homemade one, I’ll compare right here) , at a cost of 60 pounds sterling, out of greed I counted the double-dipole antenna, after which I climbed into the wilds of the Internet, where comrades vied with each other in praise Simple 2 m/70 cm Vertical Dipole Antenna" antenna suggested by Zed. It was its parameters that corresponded well to the calculations and dimensions that I made on my own. Having decided that two elders cannot make a mistake independently of each other, I went to the nearest hardware store (B&Q), looking for something that can be used to make two J-dipoles.


Despite the fact that I was initially looking for steel rods, I happened to stumble upon a department where, among various decorative profiles and pins for every taste, color and material, I saw a brass tube with a diameter of 5 mm. Home from the store, I brought two meter-long brass tubes and a three-meter photoroplast pipe for making a horizontal rod.


To make the “antenna of my dreams” I needed:

• Two brass tubes, 1 meter long (diameter 5mm)
• A piece of thick foil fiberglass (approximately 25x70mm)
• Soldering iron, some solder and flux
• File
• Ruler
• Marker
• Silicone glue (polymer plumbing or hot - it doesn’t matter)
• A piece of plumbing plastic pipe (for a horizontal rod, approximately 80 cm)
• Fasteners (for attaching vertical and horizontal rods)

Well, we can start! So, first, let's look at the central part of our superantenna. We mark it so that between the two dipoles there is a distance not covered with foil equal to 44 mm. Next, mark the “ears” (don’t remove the foil from them!) to which the tubes will be soldered. In my case, the thickness of the tubes was 5 mm, and the “net” distance between parallel tubes of the same dipole should be 10 mm. Therefore, I took into account the thickness of the tubes, the distance between them on the bend and left 2 mm on each side for solder.

Next, we bend the tubes. The most nervous and careful operation, since brass tubes are very fragile and they had to be bent very carefully the first time. To do this, start from the short side and measure 159 mm from the edge + add the radius of the tube. Using a marker, draw a mark strip along which we will bend. Next, measure 10 mm and again add the radius of the tube. Now, I recommend that you look for pliers in your household; almost always, the width of their jaws is exactly 10 mm, which greatly simplifies the bending procedure using the “pliers” method.

If you don't have it at hand the right tool, then you still have to find something solid that can be inserted onto the bend, between the parallel parts of the dipole and press the bends until you achieve the “ideal 10 mm”. I got it all right the first time, because... I bent the jaws of the pliers. Next, measure 473 mm from the bend and cut off the excess part of the tube. If you did everything right, you will get a “bracket” like this. Similarly, bend the second dipole, you need TWO of them.

Now, get everything ready for assembly! Carefully irradiate the foil pad on the central part of the antenna. File the lower part of the tube, the one that will be adjacent to the foil area, and also tin it. That's it... now your task is to solder the antenna elements accurately and evenly. I used the edge of the mounting table, to which exactly along the edge I pressed the dipole tubes with a clamp. Make sure that the bend of the tubes does not climb onto the “44 mm” platform and does not move too far from its line. The more accurately you solder, the better the antenna parameters will be.

If you did everything correctly, then you will get a design like this, 99 cm long (illustration below). The next step is to solder the cable and choose how to attach your dream antenna to the mast. It all depends only on your imagination and capabilities.

Anyway, this is how I did it! Of course, you cannot screw anything metal into the area between two dipoles. To do this, I glued a plastic corner on the back side with epoxy, along which I routed the cable. I used the same plastic part as a bracket connecting the antenna chassis to the plastic pipe of the horizontal rod. You can, of course, drill a central platform made of fiberglass and thread a long one into the hole. fluoroplastic The bolt is what will hold everything together.

ATTENTION!- immediately make a mark of the dipole to which you soldered the central core, this dipole should be on top of you, and the one to which it is soldered braid - to the ground! Otherwise, no one will hear you... In the photo below, the central core is soldered to the right dipole, and the ground to the left.

Next, we simply fill the entire pad and the soldering points and cable outlets with silicone. In my case, I generously smeared everything with ordinary plumbing sealant, but you can also use hot silicone glue, the main thing is that the soldering points, the cable outlet and the area between the dipoles itself are reliably protected from water and sun. All is ready!

Now ATTENTION!- attach everything to a vertical rod and do not forget that your antenna must be at least 70 cm from other antennas and rods, i.e. The length of the vertical rod must be at least 70 cm.

Well, that seems to be all... I’ll say right away that at the time of installation I didn’t have an SWR meter at hand and I decided to check everything in situ. Surprisingly, they heard me even when I was being carried on the other side of the city, from which I concluded that the job was well done.

Well, now, let's see what SWR parameters this antenna showed in the LPD / PMR band grid.

Notice how the SWR changes depending on the transmitter output power (well, obviously, the more dope, the more it “comes back”, reducing the SWR). Anyway, this antenna performed remarkably well in the PMR range and in the first 20 channels of the LPD range. Overall, SWR does not exceed 1.6 which is quite acceptable.

Also, let's see how the antenna behaves in the range of 142-157 MHz (in different countries, the permitted ranges and special frequencies are different, so I had to test them to the fullest). As we can see, in the UHF range 144-147 MHz, the SWR of this antenna is very good and does not exceed 1.15!

Well, that seems to be all... Leave reviews, ask questions.

In most cases, when it comes to antennas, people think of large “dishes” that are installed outside a window or on the roof of a house. However, it is worth understanding that this is far from the case. The fact is that the size of the antenna depends on what frequency and wavelength it will catch. Naturally, if you want to catch a satellite signal in order to broadcast several dozen television channels, then you will need a large antenna. But you don’t always need such a signal. That is why it is worth considering such a thing as a 433 MHz antenna. This device is very different from the antennas you are used to seeing on windows and roofs. It is very small and, as can be seen from the name, does not receive the longest signal waves. Why might such waves be useful? Most people don't pay much attention to them, but if you like to fill your home with various remote-controlled items, then you'll definitely need more than one 433 MHz antenna. If you learn to use their properties, you will be able to create things in your apartment such as a radio socket or even a pet feeder with remote control. Interested? Then read the article below and you will find out what this antenna is, how to use it, where to buy it, and most importantly, how to make it with my own hands, if you don't want to spend money on a purchase.

What kind of antenna is this?

So, first of all, you need to understand what a 433 MHz antenna is. As you can already understand, this is a device that allows you to tune a certain device to a specific frequency in order to then interact with it. By installing the antenna in a specific device, you can then send it a signal to certain frequency to activate and control this device. This is very useful feature in any home, as you can significantly simplify many processes. However, not everyone can do something similar - you need to be well versed in this area in order to tune the devices to the desired frequency. But if you set a goal for yourself, you can definitely achieve it. You just have to try hard, and you should start by studying this particular antenna, since it is one of the most important elements. You should definitely know that the 433 MHz antenna comes in three types: whip, helical and etched. printed circuit board. How are they different? Which one is better to choose? This is exactly what will be discussed next. It's up to you to learn what each of these antennas are and figure out which one is best for your specific purpose.

Whip antennas

How can you get a 433 MHz antenna at your disposal? It’s quite easy to make it yourself, but you can also buy a ready-made one, which will cost you a little more, but will save you a little time. In any case, you first need to decide which type you want to get. And the first type we will talk about is a whip antenna. Its main advantage is that it has the best specifications compared to other types. That is why people almost always make a choice in its favor. Moreover, it is much easier to do it yourself. So overall, this is the best 433 MHz antenna, whether you make it yourself or buy it in a store. However, you shouldn’t think that she’s perfect. If this were the case, then there would simply be no need for other types. That is why it is necessary to separately consider the disadvantages that this type of antenna has so that you are aware of all the features before making a purchasing decision.

Disadvantages of whip antennas

The first disadvantage that 433 MHz whip directional antennas have is their susceptibility to environmental influences. The problem is the very strong reflection and interference that occurs if you try to use the antenna indoors. Thus, it is more suitable for portable devices rather than home appliances, since in homes, due to the small amount of space, obstacles such as furniture and walls, the signal may be distorted, lost and not reach the target device. So first of all, you should think about the purpose for which you are going to use the antenna, and then decide whether to buy it. However, this is not the only drawback of whip antennas, which initially might seem ideal. It turns out that the pin in this antenna must be almost (or completely) parallel to the ground plane on which the structure itself is located. As you can easily understand, in small household appliances this is very difficult to implement. Therefore, you may have already figured out that 433 MHz whip directional antennas are best suited for various portable devices of more or less large size or those on which the antenna can be installed externally. It is not recommended to use such antennas at home. But what should replace them then? As far as you remember, there are two more types of such antennas, so it’s time to pay attention to them.

Helix antennas

The easiest thing you will get is a homemade whip antenna at 433 MHz, however, as you may have noticed above, it is not ideal. Therefore, it is worth paying attention to other types, for example, a helical antenna. How is it different from a pin one? Firstly, it also has good technical characteristics, so in this regard you can use both the first and second types with complete peace of mind. What about interference? It turns out that they are also present in a spiral antenna in enclosed spaces, and sometimes they are even stronger than in whip antennas. Therefore, it remains to look at the last parameter - compactness. As you remember, whip antennas, due to their design, must either be placed on the device body or inside it, but at the same time there must be quite a lot inside the device free space, which is difficult to achieve when it comes to small appliances home use. And in this parameter, the helical antenna bypasses the whip antenna, because it is extremely compact and will allow you to make almost every device in your home radio-controlled. Naturally, a DIY 433MHz directional antenna made this way will take you much longer, but if you are looking to buy an antenna, then you should definitely look at the helix versions as they can come in handy and help you out a lot.

Antenna on board

If you need a high-quality compact collinear antenna at 433 MHz, then you should definitely pay attention to this type, that is, antennas that are embedded in the board. It means that this type It is impossible (or very difficult) to do it yourself, so they will be considered exclusively as purchased. What are their advantages over the two types described above? First of all, they have good characteristics. Of course, not as impressive as the previous two options, but good enough for everyday use. Their main advantage is their compactness - such antennas can be placed in absolutely any device. But, as mentioned above, their main drawback is that a do-it-yourself dual-band 144-433 MHz antenna on a board is something fantastic. That is why this option will not be considered further for the reason that the rest of the article will be devoted to creating an antenna with your own hands. How difficult is it to do? What will you need for this? You will learn about all this further.

Necessary calculations

But if you decide to make an antenna with your own hands, then you will need a lot of theoretical knowledge on this topic. The fact is that any deviation in the manufacturing process will not allow you to tune the antenna to receive a specific frequency. Therefore, everything must be done very accurately, so it is always recommended to start with calculations. Making them isn't that difficult because all you need to calculate is the wavelength. Perhaps you are good at physics, so it will be much easier for you, since you will understand what we are talking about. But even if physics isn't your strong suit, you don't necessarily need to understand what every variable means to make the necessary calculations. So, how is the length of a 433 MHz antenna calculated? The most basic equation you need to know is the one that will allow you to calculate the required antenna length. To do this you need first since the length of the antenna is one fourth of the wavelength. Those people who understand physics can themselves calculate the required wavelength for a specific frequency: in this case it is 433 MHz. What needs to be done? You need to take the speed of light, which is constant, and then divide it by the frequency you need. The result is that the wavelength for this frequency is about 69 centimeters, but with such detailed settings it is better to use more precise values, so it is worth keeping at least two decimal places, that is, the final result is 69.14 centimeters. Now you need to divide the resulting value by four, and you get a quarter of the wavelength, that is, 17.3 centimeters. This is the length your 433 MHz J antenna should be, or whatever style you want to use. Remember that regardless of the type, the length of the antenna must remain the same.

Use of the received data

Now you need to put the data you have gained into practice. Antenna 144-433 MHz can be made different ways, however, the practical application of theoretical information should always be the same. What is it about? First, you should always use a wire that is a few centimeters longer than the desired antenna length. Why? The fact is that in theory everything turns out quite accurately, but in practice everything will not always work as you plan. Therefore, you should always have some reserve in case something goes wrong or the signal is not picked up at the frequency you wanted. You can always easily bite the wire in a specific place once you determine the required length. Secondly, you should always remember that the length is measured from the place where the wire comes out of the base. Thus, the resulting 17 centimeters should be measured from the base of your antenna. Most often you will have to use slightly longer wire as you will need to solder your antenna. A 433 MHz whip antenna will work better the more pins you use, so you'll want to make sure each one is the same length.

Preparation of materials

So, the theory is over, it's time to get down to practice. And for this you will need to take everything you need to create your own antenna. First of all, these are the wire or rods that will make up the main receiving part of your antenna. Secondly, you will need a base for your antenna. It is advisable that it has several holes that you can use to attach pins. If these holes are missing, you will have to either drill holes or solder directly to straight metal, which is not very convenient and will not allow you to correctly calculate the length in advance. Therefore, use a base with pre-drilled holes. Naturally, you will need other things, such as a soldering iron, but everyone knows about this, so there is no point in listing all such items.

Execution of work

First of all, you need to prepare material for further work. To do this, you need to clean all the pins, tin them and treat them with flux. After this, you need to cut the pins to the required length, but do not forget to leave a little length so that you can then adjust the finished result. Then you need to start soldering - each of the pins needs to be soldered on the back of the antenna, and then take another one that will be attached to the antenna. Its length no longer plays a role, since it will serve as a holder and will not be responsible for receiving the signal. It also needs to be soldered, after which you can already admire the result of your work.

Final steps

Well, your antenna is now ready to use. All you have to do is take the final steps. Trim the excess length of the pins so that the signal is received perfectly. If you have heat shrink, use it. And remember - this is just one example of a homemade antenna. You can also make a helix antenna, but your design of a whip antenna may look completely different. However, calculations to obtain the length of the antenna are relevant in any case, and the steps to create an antenna with your own hands will also differ only in details.

Several collinear antennas are described below, all of them are designed to be made of aluminum wire with a cross-section of 6 mm square (recloser wire from which the PVC insulation has been removed). Aluminum wire was chosen because aluminum, unlike copper, is more resistant to corrosion and has slightly lower electrical conductivity, i.e. An antenna made of aluminum works no worse than one made of copper, but does not rot under our acid and alkaline rains.

All antennas are made according to the “J elbow and phase-shifting loops” scheme and are bent from a single piece of wire. By default, the antennas are calculated for PMR 446 MHz, but can be easily converted to LPD 433 - 434 MHz.
The width of the short-circuited line forming the J elbow for all antennas is 20mm, the length is also the same 1/4 wavelength or 168mm, only the feeder connection points are slightly different.

Collinear antenna 2 x 5/8 plus 1/2 L

Collinear antenna 3 to 5/8 plus 1/2 L

Collinear antenna 4 to 5/8 L

Collinear antenna 4 x 1/2 L

The antennas are adjusted by selecting the location where the feeder is connected to the J elbow and by slightly trimming the last, topmost element, since only this element is subject to the shortening factor.

The antennas together with the J elbow, as mentioned above, are bent from a single piece of wire; the “counterweight” going down from the J elbow is then mounted using the twisting method.
When assembling the antenna, all distances are measured from the center of the wire, and not from the boundaries, the measurement accuracy should be no worse than 1 mm.
Please note that the measurement error in the elements of the main antenna fabric is cumulative, that is, if when bending the first knee, counting from the bottom of the J knee, we made an error by +2 mm, then we can correct this by making the length of the phase-shifting loop that follows it less by 2 mm. If the error there is +2mm, then the total error will be +4mm, if we make an error by another 1mm in the next leg, then the total error will already be +5mm, which will inevitably lead to a drop in the antenna gain as a whole at the design frequency.

So that those who want to repeat the antennas can imagine how to bend the antenna, here is a photo of a ready-made antenna 4 x 1/2 L on PMR:

When connecting an antenna, it is desirable that the feeder be diverted at least 1/2L at an angle of 90 degrees to the antenna surface.

The collinear antennas themselves, made of wire with a cross-section of 6 mm square, do not have structural strength and are not able to support themselves, so they are secured to a plastic fishing rod with polyethylene ties. As tests have shown, the plastic of Chinese fishing rods is radio transparent and does not affect the parameters of the antennas.

Phase-shifting loops can be made in another way - in the form of 1 turn, with such a diameter that its circumference corresponds to the length of the phase-shifting loop.

If it is necessary to recalculate one of the presented antennas at 433 MHz, then all its elements are lengthened in proportion to the change in frequency, that is, the length of each element, including the lengths of the J elbow and phase-shifting loops, must be multiplied by 446/433 or 1.030023094688222.

Two cars is a company, and three is already a convoy. And the more participants, the more difficult it is to coordinate. The issue of prompt and reliable communication is acute. It would seem that the simplest and most obvious option is cellular communication. But it has several serious disadvantages: dependence on the availability of a cell tower, the need to wait for a connection to be established, and operator services are not free.

We quickly and decisively get rid of the operator cellular communications, we move from digital to analog, go into the legally permitted frequency range - and we get a civil band radio station (CB, LPD or PMR). We are no longer dependent on the infrastructure of the intermediary operator, we can quickly communicate with each other by pressing one button, we only pay for batteries or battery charging. But here, alas, there are some shortcomings.

There is such a thing as stable communication range. It consists of the transmitter power, selectivity and sensitivity of the receiver, the efficiency of the transmitting and receiving antenna, the level of electromagnetic interference, obstacles between the receiver and transmitter, and so on. That is, for maximum quality communication, we need to take a powerful transmitter and a high-quality receiver, install an antenna with high gain, find a frequency free from interference and try to remove all obstacles. This is how we smoothly and unobtrusively came to a set of equipment for a basic amateur radio station, with which you can communicate over tens, hundreds, or even thousands of kilometers)

Our task is more modest: as a rule, when moving in a convoy, a particularly large communication range is not required; a few kilometers should be enough (provided that the crews are disciplined and do not tend to stretch out and get confused about who is going where). The “entry threshold” is also important - it is obvious that the CB (27 MHz) band is optimal for land mobile radio communications, but in order to communicate in this range you will have to install a rather long antenna on your car, which not everyone is ready to do - there are a lot of problems. On the LPD and PMR bands, the antenna length requirements are much lower. Therefore, the most logical option seems to be the purchase of portable transceivers in the LPD/PMR range (433 / 446 MHz), that is, exactly what most people mean when they hear the word “walkie-talkie”.

Models included in the LPD/PMR ranges are sold great amount, as a rule, most of them come in a set of “two radios”. The legislation provides for a limitation of the maximum transmitter power for LPD (433MHz) - 0.01 W, for PMR (446 MHz) - 0.5 W. The use of external and directional antennas is prohibited. In fact, you can easily purchase an LPD walkie-talkie with a power of, for example, 4 watts - and where is the radio frequency center looking?))

Since we are not paid money for reviews, the radios were collected as best we could - from Kadabra.

The following company was selected:

Midland GXT-1050

Voxtel MR-190

Motorola T5622

*apparently a subtle hint that the radio can be “opened” to greater power

Cobra MT600-2

Baofeng UV-5R

This walkie talkie covers a much larger range than conventional LPD/PMR. It is possible to work on reception and transmission from 400 to 480 Mhz. Also, there is a second band (the so-called “two”) 136-174Mhz, which allows this transceiver to be regarded as an amateur radio device.
It was possible to test it with a standard and an extended antenna, so the tables will periodically contain either one or both options.

Separately, out of the calculation (because the connection with her is such that it’s easier to shout at each other through the window) C.B.-portable

Midland Alan 42

We immediately decided that we would conduct tests exclusively while inside the car, that is, we deliberately complicated the conditions. Everything had to be as close to reality as possible, because you wouldn’t constantly stop on the side of the road and climb a hill to transmit some information to a distant subscriber.

Two types of terrain were chosen for testing: a city with dense buildings and a suburban highway. In this case, two series of tests were carried out in each location: in the presence of line of sight and in the presence of obstacles between two subscribers. For the test, we took two first-generation Kia Sportage cars, on which sets of car CB radio communications were installed - through it we maintained constant communication between the crews.

The tests themselves looked like this: both cars stop at the same point (A), one car remains in place, the second moves away to a given distance (measured GPS navigator in a straight line) and stops. We turn on the first set of radios, the first machine calls the second, then vice versa, we write the rating on a subjective ten-point scale, turn off the radios, take the next set, and so on until we check everything. After this, the first car continues to stand in the same place, and the second one moves on, and everything starts all over again.

And so, the first location is “city”:

The long and straight Bogatyrsky Avenue came in very handy. The connection was measured in a straight line along it. The results were recorded from the subscriber's point of view in that particular vehicle. That is, there were situations when the subscriber in car No. 1 did not receive the subscriber from car No. 2 at all, while at the same time the connection in the opposite direction was quite good. This may be explained by the presence of electronic interference at different points in the location, which blocked reception but did not interfere with transmission. These are the results:

City, line of sight

City, with obstacles (houses, urban areas) Either we were unlucky that day, or it’s always like this, but the LPD range turned out to be completely polluted - there was some kind of interference everywhere, builders, security guards, on almost every channel there was either something making noise or someone talking. The PMR range, despite its only 8 channels, was clean - a minimum of interference and extraneous conversations. CB was very surprised - after 2 km it became extremely difficult to communicate. However, this is natural for the city, because... at 27 MHz, every urban technogen interferes greatly with interference, which at 433-446 MHz remains unnoticed.

1. Baofeng took the lead by a wide margin - this is not surprising, with 4 watts of power and an effective antenna it is difficult to compete with it. At one point, the standard antenna began to receive reception even better than the elongated one - the possibly more efficient antenna, thanks to its sensitivity, was able to “catch” some kind of interference that the short one “did not hear.”
2. In second place in terms of range was the Midland GXT-1050.
3. Unexpectedly, Voxtel MR-190 took third place.
4. Cobra MT600-2 - one of the radios in this set turned out to be defective and refused to transmit normally; the connection had to be assessed in one-way mode.
5. Motorola T5622 is an amazing walkie talkie. It would seem that this was a fairly powerful signal, which confidently opened the noise reduction up to 2 km in a straight line. But the modulation is so disgusting that it is completely impossible to make out the words. The feeling that a person is talking with his mouth taped. Therefore, there are two scores in the cell - voice intelligibility scores and Roger Beep intelligibility scores (the end of transmission signal sent by the radio automatically when the button is released). Honorable last place.

Midland Alan 42, which was not participating in the competition, dropped out of the fight already at 500m. The fact is that even at such a ridiculous distance he had to get out of the car onto the street - when transmitting from the passenger compartment, he could not even open the noise suppressor for the other subscriber. He performed 1 point on the pass, after which it became clear that there was no point in wasting time on further testing it. The axiom was again confirmed that it makes sense to work in the CB band only if you have a fairly serious set of equipment. There is no place for laptops here.

We move to the second location - “country route”

Route in a straight line According to the arrangement of seats, the picture turned out to be the same as in the city - Baofeng, Midland GXT, Voxtel, Cobra, Motorola. In the test with unevenness at the 2000m point, Baofeng unexpectedly gave way to Midland - most likely we came across some kind of interference at this frequency, perhaps we should have tried other channels, and the picture would have changed.

The “straight line” test had to be stopped at 2000m due to the fact that the flat asphalt straight ended there, and then there were turns. Therefore, it was not possible to establish the maximum communication range in a straight line outside the city. But the purpose of our research was not so much to identify the most “long-range” walkie-talkie, but to determine at what distance, in general, you can communicate comfortably when traveling in cars. By the way, CB outside the city worked quite well at all the above distances.

The conclusion is this: when using the usual popular PMR/LPD, sold in kits, when driving both in the city and outside the city - you should not be separated further than ~1.5 km - any uneven terrain, turn or other obstacle, and the communication range immediately drops very much. And the optimistic range figures stated in the brochures should be safely divided by 2.

Many thanks to my Kadabra teammates: @Turbocat, @BeeRMaN, @Michspar and @Cooleroff for providing the radios. And also special thanks to @Michspar and @Cooleroff for their help in conducting the tests.

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 doesn’t 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 you 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.

1. For more efficient work And correct settings This device should also be installed on a supporting body.
2. 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.
3. 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.
4. 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.

1. Take a simple antenna-whip from a radio. All it needs is a foundation.
2. Buy metal knitting needles with a diameter of 3-4 mm.
3. 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.
4. Next, you should solder the ends of the coil to the brass bushings. This will ensure good contact and will create additional structural strength.
5. 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.
6. Next, the SWR meter is adjusted and the spokes and coil are adjusted.
7. Then the antenna for car radios is directly installed.
8. Open the ceiling.
9. Unscrew the standard antenna, unscrew 2 screws, remove the active amplifier board and carefully unsolder it.
10. Solder a 50 ohm coaxial cable into place. It is important to maintain the order of the veins, mass to mass.
11. All connections should be sealed.
12. Route the coaxial wire under the trim and rug and lead it to the radio.
13. 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 nearby vehicles 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 is 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.