Installation of CB radio and antenna on X-Trail. Installing antennas on roof rails Self-installation of the antenna, difficulties and errors

Installing a CB radio on the roof rail Nissan X-Trail(Xtt, 2005 model year, right-hand drive, no sunroof, low roof rails (no headlights)).
(c) kaskas
The main purpose of buying a walkie-talkie is to listen to and request information from truckers and taxi drivers on the highway and around the city about traffic police ambushes.

There is quite a lot of information about CB communications on the Internet, I especially recommend reading two resources - the CB forum at http://lpd.radioscanner.ru/ (fairly adequate guys hang out); forum and articles on http://ci-bi.ru (the articles are practically interesting, but the local guys have delusions of grandeur).
In my opus I will try to note everything important points, so you don’t have to sift through a bunch of articles.

I bought an Intek M-495 Power radio and a Lemm AT-72 mount antenna.
Why them:
The Intek M-495 Power radio has an adequate user interface, a decent face, a power of 20 W from the factory (no need to solder anything), European and Russian grids (in Novosibirsk and the surrounding area everyone uses a European grid), made in Thailand (almost all others – China). In terms of money - in December 2008, 4,500 rubles.
Lemm AT-72 antenna (mounted-in, 160 cm) is the best thing in the store. I didn’t take a magnetic antenna, because the built-in one gives best quality. Gave 1200 rubles. If there was a possibility, I would take Lemm Turbo 2001 or Lemm AT 73.
(For Novosibirsk residents - the only company in the city that sells walkie-talkies at retail with a normal selection - Constanta-Svyaz).

The idea was this: put the antenna on an adapter mounted on the roof rail (no need to drill the roof), put the radio in the lower 1 DIN compartment on the beard. The antenna can also be installed in place of the standard radio antenna, without having to remove the roof trim and without having to drill a new hole under the roof rail for cable passage.
I placed the antenna on the left rail, as trees grow from the right side of the road :).

Required:
1. Walkie-talkie
2. Antenna
3. 1 piece of connector for the walkie-talkie cable (I don’t know the name, choose according to the location. And please note, there is a connector option not for the cable, but for the bayonet mount - we don’t need that).
4. 4 meters of copper wire with a cross section of 2 mm.
5. Corrugation for the wire in step 4, internal diameter 3 mm, 4 meters.
6. 1 fuse connector on the wires, 1 fuse in it for 10-15 A.
7. 2 washers with a place for soldering wires, hole diameter 6.2 mm.
8. 3 M6 nuts.
9. 2 nuts and 2 washers M8. The outer diameter of the washers is approximately 10-12 mm.
10. To connect the external speaker wire to the walkie-talkie, you need a 3.5 mm jack, mono (like headphones, only with 2 contacts).
11. Any insulated connector and a 2-pin plug to it - connect the speaker itself to the wire.
12. Wire for an external speaker – 4 meters of cheap speaker cable with a cross-section of about 0.5 mm.
13. Adapter for installing the antenna on the roof rail - must be ordered from a mechanic, see text below.
14. Speaker. I took 8 Ohm, 3 Watt, mount size 7*15 cm. If possible, take 4 Ohm, it will be louder.
15. Rubber cap for passing the antenna cable through metal.
16. Plastic ties 2*100 mm, 30 pcs.
17. 3 M6 bolts with a total length of 22 mm, for a 5 mm hex key,
18. L-shaped hex key 5 mm (you will have to carry it with you in the cabin).

From the tool:
1. Soldering iron, solder, etc.
2. Socket heads for 10, 13 and 17 (or 16 - I don’t remember). 10 requires a thin-walled head, otherwise the handles on the ceiling above the doors cannot be unscrewed.
3. Screwdrivers, including T20 sprocket.
4. Drill and 6 mm drill bit (for installing a rubber cap to pass the antenna cable through the metal).
5. M8 die (step 1.25).
6. A little Litol lubricant.
7. Sandpaper for removing paint.
8. Glue Moment (rubber).
9. Glue Moment (superglue in the form of a gel).
10. Coarse thread.
11. Cloth tape.

Preparation:
The antenna needs to be modified (especially the cable entry unit), as described in the article http://ci-bi.ru/forum/viewtopic.php?t=4. The antenna manufacturer assumed that the cable entry point into the antenna would be inside the cabin, but we have it outside, so the cable must be additionally protected from water. If the cable “sucks” water (due to surface tension, the braid draws it deep into the cable), then the characteristics of the cable will “float” after a few months. The quality of the antenna cable is very important, so when buying an antenna it is worth measuring its resistance with a Chinese :) tester - it should be equal to zero. My Chinese tester shows 0.3 Ohm when the probes are shorted; measuring the resistance of the central core and cable braid gave the same 0.3 Ohm. The length of the cable that came with the antenna (360 cm) was enough (in reality, 280 cm is enough). If the cable at the antenna turns out to be crappy, it doesn’t matter, buy a good Italian 50 Ohm cable RG-58C/U (about 40 rubles/m). The cable should not stick to the magnet; the central conductor should be stranded. The cable thickness is about 4 mm, no thicker is needed.

Then you need to make an adapter to install the antenna on the roof rail. There are no such adapters for sale, I ordered them from a locksmith friend (150 rubles). Material – best stainless steel 3 or 4 mm, or regular steel 4 mm. I made 4 mm stainless steel, I was greedy - and 3 mm stainless steel would have been enough.
See figure “adapter - drawing.jpg”. The adapter is flat, you don’t need to bend anything, so you can make it yourself.

Since we will be installing the walkie-talkie in the “beard” instead of the radio and the built-in speaker of the walkie-talkie will not be heard, we need to install an external speaker. There are few places to install it - or under the grilles of the front tweeters (high-frequency speakers; the Japanese rarely have the speakers themselves there) (fabric-covered inserts on the sides of the panel, from under them air blows onto the side windows in the area of ​​the mirrors). See Fig. “Tweeter grilles and instrument cluster cover - diagram.gif”.
Or under the ceiling trim, 10 cm back from the lamp for illuminating the map. See figure “ceiling - diagram.gif”. I don't have a sunroof, so there's plenty of space behind the map light under the headliner. The lampshade of this lamp is mounted on a spatial metal frame (welded to the roof), to which I glued the speaker. Before this, I tried to put the speaker in place of the tweeter, but I couldn’t hear it very well. The speaker on the ceiling is simply superb - you can hear it very well, and you can easily get to it by removing the lamp cover for illuminating the maps.

Antenna and speaker installation:
To install the antenna, you will have to remove the roof trim on one side. I installed the antenna on the left rail, so I removed the roof trim from the left.
So, see the figure “ceiling - diagram.gif”.
The sun visor holder is removed by inserting a wide flat-head screwdriver into the hole on the side of the windshield (press the latch with it) and turning the holder 90 degrees by hand. See pic “sun visor holder.gif”.
The map backlight (No. 7) is removed by sliding it to the right (or left, I don’t remember) and lowering it down - it is attached without bolts.
The cover of the mirror bolts is simply pulled down - there are clips there.
Handles above the doors - there are grooves on top to provide access to their bolts.
The middle and rear lamps each have a pair of screws under a transparent plastic cover.
4 clips type C103 - use a flat screwdriver to get under the clip and press the latch. There are a total of 4 clips on each clip, two on the left and two on the right along the machine. We'll have to tinker.

Before doing this, it is worth removing the side trim in advance - front, center and rear.
See figure “side trim.gif”.

The front pillar trim is held on by 2 clips and can be easily removed. Before this, you need to remove the cover of the tweeter compartment (see figure “Tweeter grilles and instrument cluster cover - diagram.gif”).

B-pillar trim - First you need to remove the seat belt mount. See figure “front seat belt.gif”. The main difficulty is to carefully remove the plastic cover of the belt bolt (Adjust cover). It must be pressed out from the sides with a thin screwdriver and picked up from above. Next, remove the belt bolt, unclip the clips of the upper part of the casing and several of the upper clips of the lower part of the casing. Thus, it is possible to carefully remove only top part trim without removing the lower one (to remove the lower one, you will have to remove the sill trim, etc.).

The trunk side window trim is the main hemorrhoid here :(.
We take everything out of the trunk (you can leave the spare tire). We snap up part 18 in the figure “side trim of the interior.gif” - it is on 6 clips. We unscrew two bolts (similar bolts are unscrewed as in the photo “Foto1.jpg”) and remove part 11. Then you need to remove the lower side trim of the trunk (part 10). To do this: remove the rear left seat, remove the plug and unscrew the side fastening of the back of this seat, remove 1 clip C101, and from the side of the 5th door we gradually unclip the entire lower side trim of the trunk. There is no need to remove it completely; you need to release the lower part of the upper side trim of the trunk (part 9). Part 9 has a vertical clip (not shown in the picture), so first unclip the bottom clips of part 9 and unscrew the bolt above the window, then pull it down.

So, the side trim on the left has been removed, the left part of the roof trim is lowered and lies on the headrest of the front seat.

Remove the front part of the left rail.
See figure "railing diagram.gif". Remove the plug (part No. 3) by hooking it into the groove on top with a screwdriver. Unscrew the nut from the front railing bolt. We slide a wide flat-head screwdriver wrapped in a thick cloth under the railing, and gently rock the railing and snap off the three front clips. After unscrewing 2 nuts 13 (M8), remove the bracket (part No. 5).
We remove the paint from the upper plane of the bracket with sandpaper - the contact with the antenna adapter should be perfect. We go through the threads of the bracket bolts with a die (M8, step 1.25) to remove the paint from them. We clean the places on the roof (from the interior side) where the bracket nuts are located with sandpaper to bare metal. We throw out the standard painted bracket nuts - the washer is pressed into them, and predict the electric. I don’t see any resistance in it. Instead, we take the stored M8 nuts and wide washers for them. It is very important not to mess around and ensure perfect contact - otherwise you will disassemble the roof again.
We put the bracket in place, generously lubricating the areas where the paint was removed with Lithol (it will protect against corrosion without interfering with electrical contact).

(A small digression - I removed the roof TWO times, because the first time I was too lazy to remove the bracket and clean the paint under it. Due to poor contact of the bracket (and antenna) with the body, the radio could not be used - there was a lot of interference in reception, the transmission did not work at all And, note, resistance to direct electric current (which the tester shows) and resistance to current with a frequency of 27 MHz are two BIG differences.)

Next, a couple of cm forward from the first bolt of the roof rail, drill a hole of about 5-6 mm to pass the antenna wire into the cabin. Select the diameter of the hole on site so that the rubber cap fits tightly into it to pass the antenna cable through the metal. Before installing the rubber cap, lubricate the hole with glue. Moment - it is important to ensure waterproofing. Wrap the antenna cable at the crossing point with fabric insulating tape and lubricate it with Moment glue.
We introduce the antenna cable (in slang - “feeder” :)) into the cabin. I connected the cable to the antenna from the back so that less water would get into the place where the cable enters the antenna.
While the roof is disassembled, this is a good time to reattach the external speaker. First, solder a 15 cm wire to the speaker and a connector to the wire - this may come in handy in the future if you need to remove the speaker. I glued the speaker to the spatial metal frame on which the front lamp is attached. I glued it with some kind of superglue (also under the Moment brand), which is in the form of a gel and hardens in 10 minutes. If the speaker has an open magnet, then you can simply magnetize it to the roof.
We fasten the antenna cable and speaker wire with zip ties to the bundle of wires running in those places, going down the left front pillar.
There is no need to cut the antenna cable, as later you may want to install an (illegal in Russia) amplifier. It is generally forbidden to cut the cable of magnetic antennas; the cable of a built-in antenna can be cut if the antenna is good and installed well.
For the result, see the photo “antenna - general view.jpg”, “antenna - adapter.jpg”.

The roof can then be assembled.

Making food for the radio
I read on the Internet that the radio must be powered by a separate wire from the battery (check out http://ci-bi.ru/forum/viewtopic.php?t=498). But who believes what is written on the Internet? :). It is reasonable to take the mass (working zero :)) for power supply with a short wire from the body; there is no point in pulling it from the battery - the cross-section of any wire you lay will obviously be smaller than the cross-section of the wire by which the battery is connected to the body. If the resistance in the negative wire is greater than the resistance of the antenna cable braid (which connects to ground at the antenna), then there will be unnecessary interference in reception.
The first time I was too lazy to pull the positive wire from the battery, I soldered it to the wire of the second power connector for the radio (square connector, three wires - zero; constant 12 V; ACC, that is, 12 V with the ignition switch on). The result is that when the radio was transmitting, the brightness of its screen dropped by half, and when it was receiving, there was a strong howl, proportional to the engine speed.
So, it is necessary to pull the positive wire from the battery.

For the power cable, its cross-section is important. I was unable to find a single stranded copper wire on sale, so I bought 4 m of acoustic cable with 2 mm wires and split it into two wires, fortunately it was easy to separate by hand.
It is vital for the fate of the car to avoid short circuit laid wire to ground. Therefore, we place a fuse in the wire at a distance of 10 cm from the battery. (see photo “power - connection to acc.jpg”) Next, the wire should be laid in a corrugation. I already had a corrugated cable from the alarm wires (cut lengthwise), and I stuffed the wire into it. See photo “food - corrugated.jpg”. We lay the corrugation with the wire along the engine shield, next to the thin metal pipes of the air conditioner. We run the corrugation into the passenger compartment through the hole in the driver's legs - you can crawl up to it from the passenger compartment without disassembling anything. See photo “food - entry to the salon.jpg”.
In the cabin, you need to remove the right grille of the tweeter, then the cover of the instrument cluster and then tighten the 4 screws securing the driver's glove compartment. See Fig. “Tweeter grilles and instrument cluster cover - diagram.gif”.
Under the driver's compartment there is a standard connection point for ground wires, and next to it there is an M6 bolt welded into the body. Let's take a lot from it.
When connecting directly to the battery, you must be careful not to leave the radio on overnight. To automate turning off the radio, you can run it plus power through a relay controlled by ACC power from the radio.
A batch of Intek M-495 radios had a fuse mistakenly placed in the negative wire. It needs to be removed from there - there is no point in it, and our positive wire is already protected by a fuse.

Installing a walkie-talkie
Intek M-495 has a length of 195 mm (from the front panel to the edge of the radiator fins), which is a little too much when installed in the lower 1 DIN socket - the radiator fins rest against the plastic air duct deep in the instrument panel, the antenna cable does not fit a centimeter.
To solve this issue, you can put the radio in the top 2 DIN socket, or it needs to be modified.
I took the second path.
The antenna socket in the radio was deepened into its body by 9-10 mm. See figure “walkie-talkie - antenna socket.jpg”. This required another nut (I bought a second radio socket and unscrewed the nut from it). I couldn’t unsolder the 1165Z transformer, so I unscrewed the radiator mount and bent it with pliers back wall radio body.
We mount the radio into the 1 DIN socket.
Abroad (including in online stores, for example http://www.thunderpole.co.uk/Intek-dash-mounting.htm) you can buy a plastic adapter for installing Intek M-495 in 1 DIN, but I was crushed by a toad pay 15 pounds for a piece of plastic and wait 3 weeks.
So I did the mounting myself. See photo “walkie-talkie - mount.jpg”.
I took a standard 1 DIN plug and cut it on the right to a width of 29 mm.
Since the walkie-talkie did not fit well in length, the standard fit (when the front panel of the walkie-talkie is flush with the rear plane of the car panel covering 1 DIN connector) had to be abandoned. The radio was moved forward into the cabin by 8 mm. It turned out like this: photo “walkie-talkie in the cabin.jpg”.
I made holes in place in the standard metal fasteners. For a standard fit, an M6 bolt is screwed through the standard second hole in the metal fastener into the standard hole on the radio. To move it 8 mm into the cabin, you need to step back 8 mm from this hole. When screwing bolts and screws into the radio for the first time, do it with the radio case open, since not all holes can be screwed into screws - elements on the board can be damaged.
WITH right side I need a gasket, which I made from a 0.5 mm piece of metal. Not very aesthetically pleasing, but no one will see :).
See photos “walkie-talkie - left fastener.jpg”, “walkie-talkie - right fastener.jpg”.
For the installation result, see the photo “walkie-talkie in the cabin - general view.jpg”.

Antenna setup
Since my radio can operate at frequencies from 26 to 30 MHz, it is unrealistic to obtain resonance in such a large range. The purpose of tuning an antenna is to shift its resonance frequency (in this area the minimum SWR) to a frequently used part of the range. I plan to make the minimum SWR at a frequency of 27135 KHz - this is the frequency at which truck drivers work.
Tuning the antenna is done by changing the length of its pin; There is a bolt at the base of the antenna that allows the pin to extend.
I haven’t tuned the antenna yet, because Constanta Communications sold me a defective SWR meter. As soon as I do it, I’ll write. In general, if the Constant-Communication office has an antenna analyzer (this device itself generates a frequency signal and measures the SWR; with an SWR meter, the signal is generated by a walkie-talkie), then I will set up an antenna with them. About self-configuration antennas are definitely worth reading http://ci-bi.ru/forum/viewtopic.php?t=6 Images

In Russia, car radios, unlike car radio receivers, operate in the permitted medium wave range (27135 kHz), which radio operators call “CB”. In radio engineering, antennas for receiving VHF FM radio waves are called quarter-wave vibrators, and receiving devices for medium-wave radio communications are half-wave vibrators. Theoretically, for reliable reception and transmission, the physical dimensions of a medium-wave whip antenna should be eleven meters.

In practice, CB antennas with a rod length of one and a half to two meters are sold and installed on cars. To make such an antenna yourself, you need to have solid radio engineering knowledge and practical work skills, which is why most owners of car radios prefer to install purchased receiving devices (magnetic or built-in). Internal antennas are not suitable for car radio operation.

The best place to install a medium-wave antenna is considered by radio engineers to be the roof of the car, as the highest place in the body. From the point of view of radio engineering, the antenna pin represents only half of the receiving device. The other half of the antenna is the car body, so direct contact of the antenna with the metal of the body is important for reliable grounding. Receivers installed on the wings, bumpers, and spoilers of the car work much worse. A striking example correct installation The receiving device for radio communication can be seen in the telescopic antennas of special vehicles and government vehicles, located in the center of the roof.

A durable magnetic antenna pin 1.8–2 meters long and additional devices (coils, magnetic base, springs, rotating devices) make the receiving device heavier. Antennas on a magnetic base can be knocked down by branches hanging over the road, low garage doors, damaged, or lost.

To install a mortise antenna, you need to cut separate holes in the roof of the body, which are difficult to seal after installing the receiving device. This method does not suit most car radio owners. An acceptable compromise between magnetic and mortise antennas was receiving devices mounted on external roof rails. Plastic or metal devices for attaching the trunk or special containers are installed in the technological holes of the body, which can be adapted for mounting the antenna and laying cables. At the same time, amateur tuning enthusiasts are faced with difficulties in correctly installing and configuring the receiving device.

Selecting a medium-wave antenna according to technical characteristics

Receiving devices for car radios are unified and do not depend on the design of the radio station, so they are selected according to length, rated power, cost, quality, materials for manufacturing the pin and fasteners. Finding a ready-made antenna with a length of more than two meters is problematic; in practice, a pin height of 3-4 meters (together with the car body) is sufficient.

When choosing an antenna, you need to pay attention to the low location of the matching coil, the materials of the emitter pin (stainless steel is preferred), and the use of chrome-plated copper or brass in the housings. The power characteristics are not important; a rated power of 1 kW is enough for a powerful walkie-talkie. Particular attention should be paid to the mechanisms for adjusting the position of the pin in the matching coil. Professionals prefer reliable screw adjustments that do not get knocked down by impacts or wind loads.

SUV owners prefer antennas with rotating or folding devices. Such devices allow you to fold the antenna along the roof rail when passing obstacles hanging over the road (when entering a garage, a car wash). In the operating position, special springs return the flexible antenna to the horizontal after passing through low interference. It is important that the pin is not too soft; its bending at high speeds affects the quality of radio signal reception and transmission. When choosing a medium-wave receiving device, professionals immediately discard antennas with silumin or plastic mounts.

A medium-wave antenna of the Sirio, Alan, MegaJet brands of good quality can be purchased for $30–70. If you have not yet purchased an antenna, the specialists of the acoustic workshop of the Auto Captain service will tell you about the advantages and disadvantages in a free consultation popular models, will help you choose a suitable receiving device.

Self-installation of the antenna, difficulties and errors

In the mechanical part, the main difficulty in installing the antenna on the roof rail is the manufacture of the mounting bracket. Mortise antennas are not supplied with mounting brackets (sometimes the kit does not include connecting connectors). The main quality of the bracket, which must be made independently, is the galvanic connection with the metal of the body; ready-made brackets with rubber or plastic gaskets do not work. Professionals consider stainless steel to be the preferred material for manufacturing; brackets made of black steel quickly rust.

Antenna location

When installing the antenna on the roof rail, you need to bring the receiving device as close as possible to the car radio. Therefore, the choice of left or right railing (front or rear technological holes) depends on the location of the radio station in the cabin. Professionals think optimal location radios under the lower left edge of the dashboard. With this arrangement, the front edge of the left rail is selected for installing the antenna.

Antenna installation

When installing the antenna on the left rail, you need to pass the cables under the ceiling trim, inside the left side pillar, and connect them to the radio through the technological hole made in the bottom wall of the “dashboard”. To do this, you need to remove the ceiling trim, disassemble the rack and dashboard, correctly lay and connect the cables.

Newbie mistakes

When installing an antenna on roof rails, “do-it-yourselfers” make a number of mistakes:

• fastening the receiving device directly to plastic rails, technological holes isolated from the body (professionals call this installation “installation without mass);
• choosing the wrong material for the bracket;
• connecting the antenna to ground with a separate cable (wrong, since the receiving device must have an underlying surface);
• installation of an antenna with an inclination (affects the range, quality of reception and transmission);
• choosing a place for the antenna next to metal structures on the roof (relevant for SUVs and trucks, creates significant interference);
• intersection of the fields of a medium-wave emitter and an FM antenna (both antennas work poorly);
• incorrect choice of cable sections, poorly insulated twists;
• rough disassembly of racks, “dashboards” (amateurs do not work with special tools, they break plastic clips and latches);
• improper installation, unreliable fastening of cables (cause interference, changes in SWR values).

Adjusting the SWR can be an overwhelming task for novice “tuners”. Without going into the theory of the standing wave ratio, it should be noted that for a CB car antenna this indicator is equivalent to the efficiency. The ideal SWR value is one. With values ​​from 1.1 to 1.4, the radio works fine. Indicators from 1.8 to 2.0 are considered poor. If the SWR is adjusted incorrectly, the input stage of the radio station may burn out. To measure the coefficient, an SWR meter is used; setting the correct value depends on the depth of lowering the emitter pin into the matching coil, the length and cross-section of the antenna feeders, and the location of the antenna.

Professional installation of a medium wave antenna by experienced radio technicians

When ordering antenna installation from the Auto Captain service, the specialists of our acoustic workshop will inspect your radio station and car, determine the optimal location for installing the receiving device in the technological holes of the roof rails.

After consulting with a specialist installer of additional equipment, you will be able to choose an antenna model, buy or order it in our car store. When installing a built-in medium-wave antenna on the roof rails, our acoustics:

• they will make original brackets from the required material or adjust the mounts you purchased;
• will develop and agree with you on an installation plan;
• they will carefully dismantle the ceiling trim, pillars, and dashboard trim;
• if necessary, they will move the car radio to a convenient place and make a casing for mounting in the cabin;
• they will cut technological openings for cables in the plastic “dashboard”;
• select the required cross-sections of the coaxial shielded cable and connecting connectors (if they are not available);
• correctly lay cables, solder and insulate connections;
• secure the electrical harnesses with special clips;
• isolate the external connectors of the medium-wave antenna;
• adjust the SWR readings, set up the radio station;
• They will assemble the disassembled elements of the interior and dashboard.

In addition to installing a CB antenna, our acoustic shop technicians can perform work of any complexity, including installing retractable automatic antennas or expensive TV receiving devices.

Typical user misconceptions and mistakes in installing radios and antennas on a car

The main principle of installing an antenna: when choosing the “best” antenna, do not place it in the “worst” conditions! If it is not possible to install it perfectly, take a shorter antenna, but install it correctly. The efficiency will be much better than installing a long antenna rolled into a ring due to lack of space!

The following misconceptions worsen the quality of communication to VARIING degrees.

Antenna setup

You need to understand that ANY car antenna, bought in a store is HALF of the antenna. The second half is your car. Therefore, the antenna is adjusted exclusively on the car, at its further location. By the way, many advanced buyers ask to configure the antenna when selling. However, this cannot be done without installing it on the car (at the place where it will be used in the future). If you transfer an antenna tuned for one vehicle to a vehicle of another model, the antenna becomes untuned. Tilt of a tuned antenna turns it into an untuned one. Removing and installing the tuned antenna in the same place does not change the quality of the tuning!

Many users, having removed the antenna for the radio, which was at an angle to the roof surface, put a communication antenna in the same position in the same place. This is a mistake, because Radio receiving antennas are specially designed for a specific installation configuration. And its parameters are selected to the desired size and inclination. Transceiver whip antennas (including 27 MHz) are initially designed for vertical installation! Deviation from this position must be very carefully corrected by setting, but it is not a fact that this can be overcome, because even with good SWR antenna will work upwards rather than horizontally and it may turn out that good connection will be with Kazakhstan due to reflection from the ionosphere, and not within a radius of 10 km along the route.

Installing an antenna without mass

One of the most common mistakes when installing antennas (any whip antennas, not just 27 MHz) is installing an antenna “without mass”. As a rule, a driver who installs an antenna himself uses everyday experience, and when installing, he only thinks about making the antenna stand higher and hold it tighter.

As a result, we see:

• antennas installed on structures that do not have contact with the car body;
• antennas embedded in plastic;
• deliberately isolated from the body.

For antennas installed without mass, the maximum of the radiation pattern (direction of radiation/reception) has a significant angle to the horizon. As a result - short range, large quantity interference from the vehicle network. Particularly inquisitive owners of walkie-talkies when studying possible reasons short-range, having learned that “mass” is needed, they begin to throw all sorts of “mass veins”, not knowing that they can significantly change the circular nature of the radiation pattern and coordination. Therefore, if you have doubts about the installation method, it is better to contact specialists.

There are no complaints about the installation method, because... in some cases there really is nowhere else to put the antenna. BUT: in in this case shows a MAN TGA car with no mass on the mirror arc! This is a rare case when it is possible and necessary to use a mass core (short and thick, from the base of the antenna to the bolt securing the mirror arc to the door). There is no massive vein laid here. Here's a little tidbit. If this was a Kamaz, then everything would be correct.

Iveco Stralis car. The antenna is mounted on the mirror mount (plastic). A massive core is thrown onto the bolt. It would be more correct to install the antenna in the standard place under the visor, which is located 20 cm from the mirror. When an antenna can be installed without a mass core, it must be installed without it. In this example, the vein is very thin and long.

Installing the antenna on the roof rail

Such solutions are one of the classic installation options with an absolute lack of understanding of how the antenna works. Many people think that it just needs to be screwed to something. As a rule, roof rails do not have ground contact (but there are exceptions). If the bracket has contact with the railing, but the railing does not have contact with the ground, then the working (underlying) surface of the antenna is only the railing.

This antenna is embedded in the crossbar for floodlights. In this case, the antenna is shorted to ground with a bolt and is not an antenna, but simply a part of the body. The result is an antenna with a non-circular directivity, with maximums to the right and left along the railing. It will not work well back and forth. The range in this case is 20-50 m. The lifespan of the transmitter of such a radio station, when other aggravating conditions are imposed, can be several seconds!

There is initially no mass in both cases. On the left is installation on plastic, in the photo on the right the antenna is installed on special insulating pads. However, a mass conductor (white cable) was inserted to contact the ground and this problem was eliminated.

U installation on spoilers and plastic surfaces

Special care is required, as spoilers often do not have contact with the metal body of the car. And installation even on metal parts does not guarantee that “mass” will be obtained. In the absence of a metal roof or other convenient metal substrate, the antennas are mounted on counterweights that simulate the “ground”. Such antennas work less efficiently than those installed on a metal surface, because... To function properly, the counterweights must be the same size as the 27 MHz base antennas (i.e., about 50 cm). Counterweights press the radiation pattern lobes toward the ground, increasing range. Some radio owners, who have studied the theory of radio communications in their spare time, install counterweights (smaller in size, i.e. of a different range) to prevent short-range antennas, including even magnetic ones and antennas embedded in a metal roof. This option of “improvement” has not been studied in detail, and how much (or whether) the change in the diagram has occurred cannot be visually tracked; theoretically, no one has done this, but we are sure that there will be no significant effect.

The car is a Freightliner (“American”). There have been cases of spontaneous loss of mass on this bolt.

IVECO car (Eurostar or Eurotek). Antenna tilt too high. At this point the mass can be obtained by stripping in in the right places. Initially it is not on the plastic.

If the roof were not metal, it would be possible to do this, although the effect would not be great, because... counterweights of a different range are demonstrated.

High power amplifiers and radios.

To obtain greater range, users try to increase the output power of the walkie-talkie for amplifiers intended for installation mainly at the output of the walkie-talkie up to 4 W. Supplying more power to the input of the amplifier may not lead to an increase, but rather to a decrease in the output power of the radio station-amplifier complex.

1. Using an amplifier with an untuned antenna results in the output power actually increasing, but it does not leave the antenna. We have repeatedly demonstrated to clients

the advantage of a 4 W station with a well-tuned antenna over a 90 W amplifier on an untuned antenna.

1. Using an amplifier for a long time on an untuned antenna leads to overheating of the station and, as a result, burnout of the output stage as a result of a sharp increase in the power returning from the antenna to the output of the radio station.
2. Most buyers don't bother learning how an amplifier works, because The most suitable amplifiers have a switch button for operating in amplitude or frequency transmission, and the user, having turned on the amplifier in FM mode, operates the walkie-talkie in AM modulation. Unmatched modes do not provide an increase in power and lead to severe signal distortion.
3. Amplifiers are effective in urban areas, where due to the reflection from metal products (garages, roofs, cars...) they can provide an increased range of up to 5-7 km. When working with base stations(for example, in St. Petersburg this is the paid service “Scream”) high power is very important and 10 W at a distance of 20 km is really not enough. But along the route, where there are not so many metal objects, but there is Russian terrain, your 50-100 W output power will not help you and you will be in the same ranges as a 4 W station (namely: 5- 10 km).
4. The cheap amplifiers sold are very unreliable:

• They quickly fail and repair them are expensive;
• Sellers do not provide guarantees on them!!!;
• If not coordinated with the radio station, they distort the sound and cause noise.

Antenna protection from precipitation

In this case, the antenna connector is covered with lithol (solid oil) (according to the owner) and wrapped with tape. Antennas with contact “through a bolt” are indeed very susceptible to oxidation when installed on a bracket. Do not smear with oil or easily soldered materials, because when heated, they can penetrate the connector and break contact. Litol is a good waterproofing agent. It is enough to pour litol or silicone sealant into the protective cap (fill it completely), and then put it on. But the tape is superfluous, because... On the contrary, in this “bag” water and condensation accumulate, and the appearance deteriorates.

The same applies to magnetic antennas stuffed into plastic bags. We do not recommend using methods that cause much more corrosion than you expected.

The second option came from Poland. We mostly saw such decorations on trucks. To improve ventilation, we would recommend making small vertical slits in the upper part.

Installing the antenna near metal structures.

Due to the lack of free surface, the antenna is often placed next to metal structures. This also applies to trunks and platforms of car transporters. Any whip antenna for both a walkie-talkie and a radio is affected by all surrounding objects. They greatly change the tuning and radiation pattern of the antenna, despite the apparent insignificance of the dimensions.

There is an antenna for the radio on the drain. The radio antenna is embedded in the roof. In this case, the fact that they touch each other (even in the absence of electrical contact) can greatly deteriorate the tuning of BOTH antennas.

Apparently, the antenna for the radio kept falling down, and the driver decided to fix it that way. The reception of the radio is unlikely to have become noticeably worse, because... within the city limits, the radio tape recorder picks up on a wire thrown out into the street, but the radio has lost up to 30-40 percent of its range.

Antenna for radio. Not only did the antenna initially serve as a holder for something, because... some kind of hooks are tied to it, and the excess cable is wrapped around a metal core (side view mirror post), and a cable connected to the body of the car is also attached to the antenna pin! It is not even possible to guess what idea the owner of the antenna was implementing and what kind of super connection he was counting on.

Fig. 1: The big mistake is that the pin should not touch anything metal. If there is an electrical contact, then this is a short circuit to ground, if not (Fig. 2), then this is a strong detuning of the SWR and a strong change in the radiation pattern (directional pattern).

Radio antenna. In the city, the signals are so strong that they can be picked up even without an antenna, so all errors will appear when the signal weakens and your radio will become useless at the border of the city, and not 100 km from it.

What is possible for receiving antennas is not possible for transmitting ones. A mismatch between the antenna during transmission can cause the radio to overheat.

Installing the antenna at a low angle to the surface.

The antennas in both cases run parallel to the frontal surface of the cabin at a distance of approximately 7 cm from the underlying surface. This leads to a deterioration in the SWR even for an initially tuned antenna to 3-5 and severe distortion of the radiation pattern. This is not acceptable for transmitting antennas!

Antennas curved in an arc. This example of installation was demonstrated in the movie "Jurassic Park", which is not correct.

Installing the antenna below the level of metal surfaces.

1. BELOW ROOF LEVEL:

Fear of damaging a long antenna leads to its installation on the side walls of the body, between the cab and the van, etc. This results in not only an unsymmetrical radiation pattern, but also an incredibly poor SWR. Even if you configure such an antenna, you cannot get a long range. This is an option that combines the two previous errors.

In both cases, the antenna is installed so that behind and significantly above it are located metal frame or a metal core of a plastic body. In addition, in the latter case, the railing was also installed! It is unlikely that there is a mass there. One can only sympathize with the quality of communication! For MAZ and KAMAZ vehicles, we strongly recommend embedding antennas into the roof.

2. BELOW TRUNK LEVEL:

The antenna of the radio needs “ground” for good communication, but in the city the signal is so strong that there will be reception on wires of any length.

Antenna 27 MHz. The absence of a “ground” and shielding by the trunk wall nullify the benefits of using a good long Alan 9 Plus antenna.

Changing the angle of the antenna while the car is moving.

Decorating a flexible antenna with various objects leads to an increase in windage and, as a result, inertia. The antenna sways more than without a load. Due to this oscillation, the SWR changes during movement. With some settings, SWR fluctuations occur from 1 to 10. In this case, the walkie-talkie is a candidate for combustion, not to mention the quality and range of communication.

The use of two antennas per radio.

Based on everyday practice, some believe that if one head is good and two are better, then two antennas (tracker) catch the signal better than one. However, the use of trackers is quite controversial, because The radiation pattern of the paired antennas does not have a circular radiation pattern. If everything is done correctly, then the tracker pattern looks like in Fig. The antennas are located on the sides of the car and are indicated by bold dots (top view). We see that the maxima of the pattern are directed forward and backward of the car, and the minima are directed along the axis connecting the two antennas. It turns out that we have a gain in amplification forward and backward, and to the sides - up to the absence of communication, i.e. A NARROW-directional antenna, not a circular one!

Because Our roads are by no means straight, so at the slightest turn in the road, communication can be lost. However, if you set exactly this task, i.e. increasing the range forward and backward along the vehicle, then this is true... ideally... provided that:

The distance between the antennas is 1/4 wavelength (2.75m),

The cable lengths to each antenna are exactly the same.

At the slightest violation of these main conditions, a reversal of the pattern in an UNKNOWN direction is observed. Setting up such a system is very difficult, because... is determined not only by the SWR parameter of EACH antenna, but also by the LENGTH of the cable from the adder to the walkie-talkie and much more, the study of which is absolutely not worth the result obtained.

Some users install symmetrical identical antennas, connecting one to the radio (tuning the antenna to this range). The effect for the radio is beyond anything expected. But this spectacle misleads everyone else.

Set it and forget it.

Most users do not realize that over time, the properties of the system, consisting of a walkie-talkie, antenna, connectors, cable, and mounting, change over time.

• The antenna pin becomes loose;
• The radio has a connector that connects it to the antenna;
• Contacts oxidize;
• The fasteners oxidize and mass is lost;
• The cable becomes pinched, wears out, becomes numb, and loses its seal due to temperature changes.

This happens even with embedded antennas, not to mention those installed on fasteners.

Therefore, it is advisable to carry out inspection and maintenance of the system when the season changes (i.e., 2 times a year): clean the connectors, fasteners, tighten the connectors, ring the cable, etc. If you don’t do this, then at some point the range and quality drop, and the radio burns out, although initially you set it up and did everything according to the rules.