SB radios (CB, "CB") are those that work in civil band frequencies, namely 27 MHz. Registration is not required to use this device. The frequency is divided into a so-called channel grid. In the early days of radio communication, there were only 40 channels. But after this amount was not enough, they began to break up and designate with alphabetic characters. In this way, correct setting walkie-talkie requires the correct installation of channels.
Radio communications are actively used by taxi drivers and truckers as more reliable than mobile communications. There is no need to pay the operator for a call, to depend on its coverage network. But as a minus, you can call a limited range, as well as the possibility of interference and congestion of the channel.
But if you choose and configure the antenna for the walkie-talkie correctly, you can achieve high-quality stable communication over a wide distance. Of course, the range also depends on the equipment itself. Somewhere it is 5–7 kilometers, but there are models with more than 20 km. But the importance of a good antenna is often underestimated. But in many ways it is she who determines the range of signal reception. Do not rush to buy a very expensive radio, it may be that such a price is due to the presence of a large number of functions that are not always needed. And when you connect a good antenna to fairly budget equipment, you will achieve the same result.
Antennas for car radio can be divided by type of installation:
- on mortise;
- magnetic.
The mortise antenna is mounted in the body. Moreover, when installed on a hood or fender, it loses its effectiveness by 30-40%. You need to install as far as possible from vertical metal parts that are parallel to the base of the antenna.
Magnetic antennas do not require tie-in, and are usually used on cars. On large trucks, they may fall off due to vibration. Such an antenna for a walkie-talkie can be easily installed and removed, transferred to another car.
And also antennas for car radios differ in size:
- Long with a pin of about 2 meters, create the highest quality and stable connection.
- Medium ones from 90 to 170 cm, have a lower gain and work at a shorter distance. But they are more convenient because they do not touch such upper obstacles as bridges, tree branches, power lines.
- Short 65–70 cm, comfortable and not so noticeable, but providing a short reception range.
The most effective are long mortise. But even a good antenna needs proper installation and tuning.
Installation
An important factor in a good signal is the correct installation of the antenna:
- Attach to the top of the body on a stable base.
- Installation on bumpers, doors, mirrors reduces efficiency.
- Install vertically unless otherwise stated in the instructions. If you need to install at an angle, you must first mount and then adjust. It is in this order, and not adjust, and then tilt.
- The surface area on which the installation is made should be as large and flat as possible.
- Try not to put on the hood and trunk.
- The antenna itself and the connecting cable must be located as far as possible from sources of interference, such as the ignition system.
Setting
Before using the antenna for a walkie-talkie, it must be configured. If this is not done, you will not receive the declared reception quality indicators. Setting instructions:
- The adjustment must be made under the same conditions as the operation of the vehicle. That is, among other cars, and not in the garage.
- Mount the antenna securely to the vehicle. You don't have to hold it in your hands.
- You will need a device called an SWR meter. Connect the cable with one end to the antenna, and the other end to the SWR meter in the ANT connector. Next, connect the device to the station (Trans connector and antenna connector of the station).
- Set the FWD / REF switch on the SWR meter to FWD, and SWR / PWR to SWR (some models may not have this switch).
- Press the gear and adjust the dial to the end of the scale.
- Set FWD/REF to REF. Record the instrument readings. The ideal value is one.
- Next, measure the SWR sequentially from the highest frequency to the lowest.
- If the minimum SWR values are at a frequency below the operating frequency, then it is necessary to shorten the antenna. Otherwise, increase.
The following options are possible:
- SWR in at least one of the grids is below 2. This means that the antenna is working and installed correctly.
- SWR is 2.5 everywhere - Perhaps, somewhere there is a deterioration in contact with the body. And check the integrity of the connecting cable.
- An SWR above 5 means the antenna is not working.
Antennas for walkie-talkies are classified as follows:
- Spiral broadband - small length, low efficiency.
- Dipole artificially extended - medium efficiency, but works in good quality in a narrow frequency range.
- Dipole single-range - the most effective of the presented, but have a long length and work only in one range.
For your radio model, you can choose the appropriate antenna for changing. You can set up and check their indicators in the same way. But in case walkie-talkies the characteristics as a whole are important for high-quality communication at remote distances.
These are the principles for choosing, installing and configuring antennas for a walkie-talkie. You can choose the appropriate types based on the purpose of use and on which vehicle the installation will be carried out. If you know more good antenna models or the secrets of their installation and configuration, be sure to share your opinion in the comments.
Setting up radios. Alfa-Radio performs the following types of work:
2.
We make adjustments in Moscow and the Moscow region car radios SI BI 27 MHz for the frequencies of truckers, SWR antennas for cars and trucks, tuning the base antennas SI BI 27 MHz, VHF, DTSV.
Alfa-Radio provides services for tuning the SWR (standing wave ratio) of the antenna. The cost of tuning the antenna depends on the availability of the installed radio station for connecting the device, the location of the antenna, the type and length of the car antenna pin. Simple antenna tuning - tuning an antenna on a magnetic base or a mortise antenna (an antenna embedded in the middle of the roof of a car) within the standard travel for setting up a pin on a car is from 300 rubles. up to 500 rubles The cost of more complex SWR tuning with the need to shorten the pin or replace it with a longer one, tune antennas on trucks, tune base antennas ranges from 500 rubles to 1500 rubles.
Check Antenna SWR we recommend that it be carried out as planned - once a year or if the quality of the radio has changed. It is important to remember that when working on an untuned antenna, the radio's output power transistor may overheat and eventually fail. You can learn more about the service in the section - setting up car antennas.
3. Setting the channels of base radios (radio stations) and signal repeaters.
4. Setting up basic antennas of different types.
Car antennas of the CB range after purchase require a mandatory SETUP!!! These actions guarantee you a high quality of communication and save your radio from failure (in 90% of cases, with an untuned antenna, the output stage transistor burns out). This article lists 9 points that you NEED to know before buying and operating a CB antenna and walkie-talkie.
1. The antenna must be tuned. Any antenna installed on a car requires SWR adjustment, and even if the antenna is on a magnetic base, it will require SWR adjustment every time it is installed in a different place from the original one. An installed antenna without adjustment and tuning will not work fully, and after a while (or maybe immediately after turning on the radio for transmission) it will fail due to severe corrosion and wetting of the cable.
2. The length of the antenna determines the quality of work, of course it all depends on the setting. You can fully tune the antenna only with the help of an SWR meter (which should be calibrated to a load equivalent of 50 ohms before tuning) or an ANTENNA ANALYZER!
3. Antennas on a magnetic base lose to mortise antennas installed permanently due to the lack of electrical mass (-). Each type of antenna has its own key features- magnetic antennas require finer tuning, due to the lower possible power supplied, they do not combine well with amplifiers and because of the magnet they rub the body paint. It is also worth remembering that at high speeds (more than 120 km / h) such antennas fly off and can return back - right into the glass and knock out or split it. The antenna cable is also an element of coordination, you should not try to change its length, it is desirable to lay it straight, without unnecessary turns and twists, as this affects the antenna tuning. Mortise antennas mounted on a bracket or directly into the body are not completely removed - it is only possible to disconnect the pin with the coil, and the base with the supply cable will remain in place, such antennas have more stable operating parameters and their frequency range is usually wider. The efficiency of the mortise antenna is HIGHER, and the reception interference is LESS!
4. The antenna is tuned to resonance with the car body, so any interference with the "radio-antenna" system requires subsequent tuning of the antenna. Therefore, the adjustment is made only after you have installed all the elements in their places and have wired the cable.
5. Protection against corrosion and damage. We live in climatic conditions different from European ones - lower temperatures, different humidity indicators, etc. In this regard, the antennas are recommended to be slightly modified, which in fact is an adjustment to our more severe climatic conditions. Experts recommend treating the joints of dissimilar metals with lithol and strengthening the place where the cable is inserted into the body as efficiently as possible. Never smear the inductor with fuel oil, etc. The coil must always remain dry and clean!!! Otherwise, the capacitive characteristics of your antenna may change, and this may lead to tuning problems. Moreover, many fuel and lubricant lubricants contain graphite. Graphite is one of the best conductors electric current.. It is best to contact specialists for revision!
6. The optimal location for the antenna is the top of the body, the center of the roof. Antennas installed in the center of the roof of the car makes the radiation pattern closer to circular (in this case, the antenna begins to receive and transmit equally well in all directions). It is not recommended to use the hood, trunk and bumper for antenna installation. With this installation, the antenna loses efficiency by about 2 times, and sometimes it simply does not tune.
7. If the Magnet is big. It often happens that it is simply not corny to install a mortise antenna, this is especially true if the car is not personal or is under warranty and it is forbidden to install additional equipment. In such situations, it is recommended to give preference to the maximum diameter of the magnet.
8. Antenna cable must be solid without twists and its length must be varied multiples. For the main types of antennas, multiple cable lengths are allowed: 3.40-4.00 meters, and the next allowable length is 7.30-7.90 meters. A cable that is mechanically damaged or made up of several pieces will have large electrical losses in the high-frequency signal and will lead to an increase in airborne noise and loss of transmission power.
Setting up antennas and walkie-talkies
The online store site is a walkie-talkie, antennas and other goods for radio amateurs and professionals at a bargain price. In our assortment there are always antennas, power supplies, accessories for radio stations, voltage converters, and, of course, it is from us that you can buy cheap radios and carry out their professional tuning.
If you have any questions regarding the selection of the desired model of a walkie-talkie, antenna, or any other product, please contact us by phone or by e-mail. If you are still looking for where to set up a walkie-talkie inexpensively, we guarantee the lowest prices.
The online store of radios, antennas and accessories Radioroom.com presents models of all world famous brands: Yaesu, radios and antennas Midland, Kenwood, Motorola, Megajet, President, Vector and many other goods you can buy cheaply.
The article is written for beginners, those who are going to set up the antenna for the first time to work on the channel (frequency) they need. Those who have already repeatedly tuned antennas are unlikely to find something useful for themselves in the article.
The article describes the main points of tuning simple single-band antennas - car mortise, on a magnetic base, basic 1/4 GP, 1/2 (half-wave), 5/8 (five-eighths).
What you need to tune the antenna
SWR meterA device that shows the ratio of the direct (coming from the radio station to the antenna) and the reverse (reflecting from the antenna) waves in the cable.
Indirectly, this device shows that the output impedance of the radio station is equal to the cable impedance, and it is equal to the antenna impedance. You can read about what wave resistance is and how it differs from that shown by a conventional tester in the article:.
An SWR meter (SWR meter) can be purchased (the issue price is about 1000 rubles) or you can temporarily ask someone you know who has one.
radio station
The SWR meter does not work without a radio.
The more "grids" there are in the radio station, the wider the frequency range the radio station can be tuned, the easier it will be to tune the antenna to the desired frequency (channel).
With a radio station with 40 channels at 27 MHz, it is possible to tune the antenna, but it is very difficult, with a radio station that has 400 or 600 channels, this is much easier to do.
Roulette or ruler
It will be required to measure the antenna web and determine how many centimeters to shorten or lengthen.
In principle, you can do without a tape measure or ruler and perform the adjustment simply step by step, slightly shortening or lengthening the antenna web.
Fundamentals of Antenna Tuning
The antenna must be adjusted in the place where it will then stand.That is, the antenna must be tuned in the conditions in which it will continue to be used, especially if at a distance closer than 2-3 wavelengths (wavelength = 300 / frequency in MHz (for 27 MHz, the wavelength is about 11 meters)) there are some conductive objects parallel to the antenna web.
If this is a basic antenna, then you already need to prepare a mast for it, which allows you to remove and install the antenna, raise and lower it all for setup and maintenance.
If this is a car antenna, then the car should be parked so that there is exactly the situation nearby that will be when driving it at the time the radio station is operating, that is, other cars were standing at a distance of about 5-10 meters, but on the other hand, it should not be nearby be the walls of reinforced concrete houses, garages; you cannot stand inside an iron garage or hangar. At the time of measurement, when setting up, the car doors and trunk should be closed. You should not stand next to the car yourself, the human body absorbs radio waves and thereby introduces losses, affects the operation of the antenna.
There should be no moving conductive objects at a distance of 2-3 wavelengths from the antenna.
All instrument connections must be reliable.
You should not keep everything "on weight", pressing with your hands to the contacts somehow stripped pieces of cable that are about to fall out of the connectors or are closed.
Reliable connections are needed so that the readings of the device do not change as they please, do not float and are repeatable. If the readings are not repeatable, then these are no longer instrument readings, but the weather on Mars at the time of eating Snickers, and it is impossible to focus on such readings.
How to use a SWR meter
We connect the cable to the antenna, the other end of the cable to the SWR meter, to the "ANT" connector, the connector of the SWR meter "TRANS" is connected to the antenna connector of the radio station.We turn on the radio station and set the frequency at which we will measure the SWR.
If there is a SWR / PWR switch, we translate it into the SWR position.
SWR meter switch "FWD/REF" to FWD.
We press the transmission on the radio station and set the arrow sticking out of the SWR meter with the regulator to the end of the scale. Let's release the transmission.
Set the "FWD/REF" switch to the REF position.
We press the gear and count the SWR reading on the indicator. On most SWR meters, the less the arrow deviates, the less SWR, if it does not deviate at all, then SWR \u003d 1 or the device is dead. If at all frequencies, in the REF position, the arrow does not deviate, then either you have a good equivalent load connected instead of the antenna, or the device has died, but let's not talk about sad things.
Antenna tuning - step by step
We connect everything to measure the SWR, as mentioned above, the antenna to the working position.- We set the radio station to the highest frequency that the radio station is capable of delivering, for example, grid G channel 40 (more precisely, see the instructions for the radio station).
- We measure the SWR, moving down the frequencies in about 20 channels (200 kHz), remember at what frequency (channel, grid) there was a minimum of SWR and which SWR was at a minimum.
Now there are several options:
The SWR is large everywhere, the device "scales".
Either you use the wrong SWR meter or you have a break in the cable or antenna.
SWR smoothly, as the frequency decreases, but we did not reach the minimum.
Your antenna is too long. Need to be shortened. In shortening, it is worth remembering the golden rule: "measure seven times, cut once." It is impossible to stick a shortened one back in most cases, so we shorten it a little, for CB antennas in the 27 MHz band it is a little about 1 centimeter, for LPD or PMR antennas in the 433-446 MHz band it is a little 2 millimeters.
The SWR increases as the frequency decreases.
Your antenna is too short. The antenna needs to be extended. How exactly - better by 20 percent, and then shorten.
The SWR decreased as the frequency decreased, at a certain frequency it became minimal, and then, as the frequency decreased further, it began to increase again.
This is the most common case.
This behavior means that everything is fine, the antenna is operating in the desired range, it remains only to adjust it to the desired frequency (channel).
If you have this case, then it is advisable to find exactly on which channel the minimum SWR is.
If the frequency at which the minimum SWR was lower than what you need, then the antenna should be slightly shortened, literally 5 millimeters each, if we are talking about the 27 MHz range, after each shortening, look where the minimum SWR is now, and shorten it until the minimum The SWR will not be at the desired frequency.
If the frequency at which the minimum SWR was higher than you need, then the antenna needs to be lengthened.
What to do if the minimum SWR is at the desired frequency, but this minimum value is still large
This suggests that the antenna does not work quite the way the manufacturer intended or the antenna is rubbish, but you don’t need to immediately talk about sad things.If this is a car mortise antenna, then maybe it "does not have enough mass", that is, contact with the mass is poor.
If this is a car antenna on a magnet, then it may also "not have enough mass", for example, the paint layer is too thick.
Or your car antenna stands where it should not be placed - next to the elements of the metal roof rack, next to the additional light that you hung on the trunk, you generally magnetized it to the hood or trunk, bumper or wheel disk.
Maybe you fixed the mortise antenna on the aluminum skids of the trunk that you have on the roof, but the trunk turned out to be not aluminum but plastic or does not have reliable contact with the mass of the car, or is not long and wide enough to act as a mass for the antenna.
If the antenna is on a magnetic base, try to look for another place where to "slap" it, try from the corner of the roof, in the center of the roof, from another angle.
RF currents do not flow exactly like DC, where the tester shows excellent contact, for radio frequency this can be a bottleneck.
If the antenna is mortise, see if you cleaned the paint well from the place where the antenna ground contact is attached.
If you mounted the mortise antenna on the trunk or some kind of fixture on the drain, try to improve contact with the ground. There were times when the author of the article took 2 pieces of wire 0.5 mm thick without insulation, wound it on a bracket on which a mortise antenna was fixed hanging on a drain or trunk, threw them into different corners of the car roof along the drains and the SWR decreased from 3 to 1, then there the antenna began to work perfectly (naturally, the signal on the air also improved).
Throwing extra wires, tearing paint and then pouring sealant or looking for other ways to improve the mass or installation point - it's up to you, it's your antenna and your car.
If you don’t have a car, but a basic version of the antenna, then the treatment here is actually exactly the same, namely: maybe you need more “mass”, or maybe you need to climb into the design of the antenna with a soldering iron.
To begin with, we make sure that there is enough mass - the pipe is the base, it is also the main counterweight, the mass for antennas of the type 5/8 (five-eighths) and 1/2 (half a wave) must be at least 1/4 of the wavelength, that is, for 27 MHz it is about 2 meters 75 centimeters. More is better; less - you have to lengthen the wire thrown over the roof.
Although sometimes it happens that everything is done well, but the antenna does not tune, as it happened with a friend of the author of the article, 1/2 did not want to tune. It seems to be in the frequency, but the SWR is not 1 or even 1.2 or 1.5 - it turned out that someone "climbed into the antenna" before it and cut off the coil coil installed inside the antenna.
It is also very likely that your base antenna is interfering with the nearby stretched optics of your provider or the collective antenna mast.
How much to cut and what is the ruler for?
Antenna dimensions depend linearly on frequency.
If the antenna is full-size, then how much it needs to be shortened or lengthened in order to get to the desired frequency directly depends on the ratio of the current frequency where it resonates and the desired frequency where you would like the antenna to resonate.
Let me explain with an example:
we have a quarter, let it be 267 centimeters long, it resonates (SWR is minimal) turned out to be at a frequency of 27.0 MHz (channel 4 of sect C), we want the antenna to work at 27.275 MHz.
We consider K differences in frequencies:
27.0 / 27.275 = 0.9899175068744271
We multiply by this K the current length of the antenna:
267 * 0.9899175068744271 = 264.3
and we get the length that the antenna must have in order to earn on 27.275.
Calculate how much to cut:
267 - 264 = 3 cm.
However!
It is not necessary to cut exactly 3 cm at once. Do not forget, the antenna is not only a pin, it is also counterweights. Everything affects.
So you can determine the order of the first cut - either 3 cm, or 5 mm.
Next, we proceed step by step.
For the above example, you can cut off 1.5 cm, again find the resonance, and based on the result, move on.
Last but not least, this should have been written first:
Basic rules for installing antennas
The antenna must be placed no closer than one wavelength to other conductive objects, especially those that will be parallel to the antenna.
The higher the antenna is installed, the better.
It is clear that for car antennas at 27 MHz these rules are simply impossible to comply with, therefore car antennas compromise, so do not demand miracles from them.
If, nevertheless, you have no time, there is no desire to deal with the intricacies of measuring SWR, look for an SWR meter, adjust the antenna yourself and you are in Novosibirsk, you can refer, for example, here: