Esteja você ouvindo um grande jogo, uma notícia de última hora ou sua música favorita, você não quer que o rádio do seu carro perca o sinal.
Felizmente, o problema com rádios perdendo sinal geralmente não é sério, e existem muitas maneiras simples de corrigi-lo.
Como regra geral, quando o rádio do seu carro perde o sinal, pode ser devido a um problema de interferência de rádio no amplificador ou no receptor. Outro problema mais comum é a estação de rádio estar fora de alcance ou uma conexão de antena ruim no carro. Depois de saber onde está o seu problema, você pode escolher as soluções apropriadas. Se você deseja um guia sobre os problemas que podem fazer com que o rádio do seu carro perca o sinal, bem como maneiras de resolver seu problema, continue lendo.
Problemas da unidade principal
Antes de prosseguir, verifique a recepção do seu sintonizador no mostrador nas bandas AM e FM. Determine se o problema está limitado a apenas uma ou duas estações ou se todas as estações desaparecem regularmente.
Se você ainda estiver captando outras estações, o problema pode estar na intensidade do sinal da sua estação favorita. Quando você está à margem do alcance de uma estação de rádio, o sinal tende a aumentar e diminuir. Você pode perder o sinal completamente, ou pode ser quebrado ou distorcido.
Alterar seletor local/distante (LX/DX)
O termo “DX” vem dos primórdios da telegrafia sem fio. “DX” era uma abreviação de código Morse para uma transmissão distante. A configuração DX em seu sintonizador FM aumenta o ganho de sinal entre o sintonizador e a antena.
Seu sintonizador está configurado para LX? Tente mudar para DX. A configuração LX (Local) filtra os sinais mais fracos e bloqueia apenas um sinal mais forte. Alternar para a configuração DX pode permitir que você bloqueie o sinal de uma estação mais distante ou de baixa potência.
O seu sintonizador já está configurado para DX? Às vezes, seu rádio pode ter uma coisa boa demais. Ele pode receber tanto um sinal local próximo quanto um sinal mais distante em uma banda adjacente. Ou um sinal local poderoso pode dominar o sintonizador, levando a distorções e cortes. Mude de DX para LX e veja se sua estação fica mais clara.
Altere suas configurações, reinicie seu receptor e tente mais uma vez sintonizar sua estação. Essa redefinição pode resolver seu problema. Ou pode ser que sua estação favorita simplesmente não tenha potência para produzir um sinal poderoso o suficiente para o seu sintonizador.
Obtenha um reforço de sinal de rádio de carro
Se sua recepção geral for boa e você tiver problemas apenas com algumas estações distantes, um amplificador de sinal pode resolver seu problema. Nesses casos, pode ser útil instalar
amplificadores de antena que aumentará o sinal que entra pela sua antena.
Seja um sinal AM ou FM, o sintonizador da sua unidade principal funciona da mesma maneira. Ele capta ou sintoniza o sinal e o aumenta antes de enviá-lo ao amplificador. O amplificador aumenta ainda mais até que seja forte o suficiente para mover seus alto-falantes.
Mas se esse sinal for muito fraco, o sintonizador terá problemas para sintonizar. O sinal de rádio e, com efeito, sua música entrará e sairá. Um amplificador de antena fica entre a antena e o sintonizador e amplifica o sinal em cerca de 15dB.
Em geral, a potência de um sinal dobra a cada 3 decibéis adicionais. Um aumento de 15 dB significa que o sinal que entra no sintonizador é 32 vezes mais forte do que sem o amplificador de sinal no circuito. Este aumento de potência pode significar a diferença entre um sinal distorcido e desvanecido e uma recepção clara.
Se você mora em uma área rural plana, um amplificador de antena pode distorcer seu sinal. Também não funcionará em “zonas mortas” causadas por colinas ou prédios altos ao redor. Eles podem amplificar um sinal fraco, mas não podem fazer nada se não receberem nenhum sinal.
Os amplificadores de antena amplificam o ruído do sinal ao lado do sinal. Therefore, if interference caused by competing radio waves or generated within your car is the problem, an antenna booster will only magnify the interference and distortion.
Lower Your Class D Amplifier’s Gain
Did you begin having trouble with radio reception after installing a new amplifier in your car? Today, many car amplifiers and the most active subwoofers boost signals using
Class D tecnologia.
But those switching transistors can also generate a great deal of electromagnetic interference (EMI). Many modern cars use the rear window’s defroster grid as a radio antenna. A trunk-mounted Class D amplifier may send that EMI into your antenna and wreak havoc on your reception.
If you have a Class D amplifier in your car’s trunk, disconnect it, then try your radio again. If the interference and signal loss vanishes, the problem likely lies in your amplifier. Reconnect the subwoofer and turn down your amplifier’s gain. This way, you can bring the EMI down to a point where it no longer interferes with your reception.
Replace Your Class D Amplifier
Another option would be to replace your amplifier with a newer model. Early Class D amps were notorious for EMI interference. As Class D technology matured, manufacturers have found ways to minimize this issue.
Unfortunately, many Class D designers today focus on creating the cheapest amplifier they can. They will choose higher wattage over better filtering and shielding. Plus, DIY subwoofer designers often prefer more powerful Class D amplifiers to higher quality builds. As a result, powered subwoofers are a frequent cause of EMI-related radio interference.
An excellent example of modern technology is the
Rockford Fosgate R500XID Monoblock which will provide 500 watts of power to your 2-ohm subwoofer. Though it is a Class D amplifier, the R500XID produces significantly less EMI than cheaper but more powerful Class D amps.
You may fret about replacing a 2000 watt amp with a mere 500 watts. But even if your cheap, radio-interfering amp really
could produce 2000 watts, it would provide only 6 dB more volume than a 500-watt peak. For radio listeners, clean power is just as crucial as high power.
Check Your Antenna-Head Unit Connections
Removing your head unit also requires, in many cases removing dashboard trim. Depending on your car, this may be a simple job or an exercise in frustration. The
Amorka 112 Piece Trim Removal Kit will give you the tools you need to get the job done.
Before you start, disconnect the negative (-) or black terminal from your battery. Move the cable to one side, making sure it is well away from the battery terminal. Do not allow the negative and positive wires to touch.
Disconnecting your battery ensures no sudden surges of unexpected current will damage your head unit while you are working with it.
Consult your owner’s manual for instructions on how to remove your dashboard trim panel and head unit.
Car Manuals Online has guides available for most makes and models. Follow the manufacturer’s instructions, using the proper nylon trim removal tools.
If you run into resistance, don’t try to move the panel by brute force. You will only end up damaging the clip, the panel, or both. Feel around for screws and bolts and loosen them. Be sure to put them in a safe place to reattach the panel when you finish.
You will probably need to remove some screws to release your head unit. You may also need to loosen clamps with a key or pull it out with a U-shaped wire tool. (Copies of these come with the Amorka Kit).
Most car manufacturers and aftermarket head units connect their antennas with a
Motorola plug . Some however, like GM, Nissan, and VW, require an adapter. Crutchfield’s
Vehicle Selector provides advice on your car’s specifications and the tools you will need.
Check the antenna connection by tugging firmly on the pin. It should be firmly in place. If the connector is loose or not in the proper outlet, press it firmly into the correct one. A loose antenna connection can cause your radio signal to cut out on bumpy roads.
If you have a whip antenna or a “shark fin,” check its connection with a “jiggle test.” Gently jiggle the base of your antenna while music is playing. If reception pops in and when you move it, the antenna is not firmly connected to the car body.
If your antenna was jarred loose, tightening the connection should solve your reception issues. But if the bolt has become corroded by weather, you will need to replace or upgrade your antenna, which we will discuss later on.
Replace Your Head Unit
If your tuner is failing, you will probably need a new head unit. Once car stereo systems were modular, adding a CD player or switching out your AM/FM radio meant installing a new component. (It was so easy to remove car stereos that many drivers placed NO RADIO signs on their windows to discourage thieves.)
Today’s head units have become an all-in-one system that controls your parking cameras, GPS navigation, and many other functions. Swapping out your stock head unit for an aftermarket model may interfere with systems you rely on for your daily driving.
Earlier cars had either a “DIN” or “Double-DIN”-sized hole in the dash. (DIN stands for
Deutsches Institut für Normung , the
German Institute for Standardization .) A single- or double-DIN component would fit in any automobile with a suitably sized opening.
Today’s automobiles place their head units in closely fitted panels that blend seamlessly with the dashboard. They use larger buttons or screens to make their head unit easier to use and to stand out from competitors.
Installing your new head unit may require machined panels that fit your dashboard. You must carefully check to see if all systems are working, not just your car audio. This will require a good bit of skill and a lot of troubleshooting.
Unless you have experience with electronics and car stereo installation, it is probably best to leave this job to professionals.
You should also search for videos of technicians installing head units in your automobile’s make and model. If you want to try installing a head unit on your own, this short video will give you a good basic idea of what is involved:
Antenna Issues
If your head unit checks out, the problem may lie with your antenna. Antennas are necessary for every radio transmission. A radio station transmits its signal through a large antenna, and another antenna picks up that signal.
Because the receiving antenna captures the radio waves along its entire length, the signal becomes concentrated the way a magnifying glass brings scattered sunlight to a point. The tuner and amplifier further boost this radio transmission and send it to your speakers.
Fix Your Rear Defroster
Your front defogger blows hot air provided by your car’s heating system over the windshield’s interior, but there are no convenient air ducts to warm your car’s rear window. Instead, the rear defogger relies on a heating grid.
The rear defroster sends an electrical current through the metal and resin grid attached to your back window. This generates resistance in the metal, which becomes hot. (The same principle is used in electric space heaters, stoves, toasters, and many other appliances.)
This heat evaporates fog and condensation on the glass. It also melts snow and ice and prevents them from sticking to the rear windshield, but the rear defroster grid works double duty in many modern vehicles. It clears your glass and serves as your radio antenna.
Thin grids are fragile. In time, the connections break down. Your defroster grid can also be damaged by a tint job. If your tinter used a metallic tint instead of the more expensive ceramic tint, it could make your rear window grid useless as an antenna.
If one or more of your defogger strips fail, this will also interfere with your reception. Replacing the defogger usually involves replacing the entire rear window, which can be expensive. Repair kits like the
Visbella DIY Rear Window Defogger Repair Kit may help you fix your window heater and radio reception for a lot less.
When you are defogging your window, the electrical current that warms the heating grid interferes with your radio reception, which is unavoidable. If you want to listen to your radio on foggy morning commutes, you will need a better antenna.
Upgrade Your Car Antenna
If your car uses your defogger as an antenna, upgrading to a mounted antenna will improve your reception. First, decide where you want your new antenna.
Roof
Roof magnets are attached with a magnet or a mounting bracket.
- Long roof magnets are prone to damage from low-hanging branches and are a tempting target for vandals.
- Shark fin roof antennas have become much more popular because they avoid these issues.
Rear Bumper
Rear bumper mounts of whip antennas (the traditional long antenna) are popular and very effective at catching signals. They require running the antenna cable through the entire cabin.
Windshield
This is the most common and easiest installation. Follow these guidelines:
- Be sure you are not applying the antenna in a place that impedes your vision while driving.
- Make sure the adhesive is firmly affixed so it does not shake off during a bumpy ride.
- Keep the windshield antenna away from the car’s metal body and not attach it to tinted windows.
If you already have an antenna on your car, it probably uses a universal mount. Simply unscrew it and replace it with your new antenna. If you are installing a new antenna, be sure to read the instructions first.
This video teaches you how to install a shark fin antenna on your car’s roof:
If you want to replace a broken antenna with a new one, check out this video to learn how:
Stream Radio Through Your Phone
Sometimes radio signals drop for reasons beyond your control. Hills and high buildings may block out a signal entirely, and ionospheric bounce may make some faraway signals audible only at night or cause interference affecting nearby stations. You may also just be out of range.
All is not lost, though. If you have a cell phone signal, you may be able to listen to your favorite radio station via streaming. Many radio stations also make their broadcasts available on the web. Find your station and stream the audio to your head unit.
If you are having difficulties getting radio signals, there’s a good chance you are also having problems with your cell phone reception. This
Pulse/ Larsen LTE Multiband WiFi Active GPS Sharkfin Antenna will improve your GPS and cell phone connections.
Considerações finais
Troubleshooting your car’s audio system can take some time and frustration, and repairing damaged parts may require technical skills, but these nine fixes will help you enjoy better radio reception.
When your favorite program comes in loud and clear, you’ll be glad you did!
Sources
- Crutchfield:How to choose a replacement FM antenna for your car
- Lifewire:How Car Antenna Boosters Work
- Popular Mechanics:How to Repair Your Defroster Grids
- Pulse Electronics:Top Seven Benefits of a Shark Fin Antenna
- SONY:How to Troubleshoot Poor or No AM or FM Reception on the Car Stereo
- WikiHow:Install a Car Radio Head Unit
