Pourquoi l'autoradio perd-il le signal ? Avec 9 corrections simples

Que vous écoutiez un grand match, une actualité ou votre chanson préférée, vous ne voulez pas que votre autoradio perde le signal.

Heureusement, le problème de perte de signal des radios n'est généralement pas grave et il existe de nombreuses façons simples de le résoudre.

En règle générale, lorsque votre autoradio perd le signal, cela peut être dû à un problème d'interférence radio dans l'amplificateur ou le récepteur. Un autre problème le plus courant est la station de radio hors de portée ou une mauvaise connexion d'antenne dans la voiture.

Une fois que vous savez où se situe votre problème, vous pouvez choisir les solutions appropriées. Si vous voulez un guide des problèmes qui peuvent faire perdre le signal à votre autoradio, ainsi que des moyens de résoudre votre problème, continuez à lire.

Problèmes d'unité principale

Avant d'aller plus loin, vérifiez la réception de votre tuner sur le cadran sur les bandes AM et FM. Déterminez si le problème se limite à une ou deux stations ou si toutes les stations disparaissent régulièrement.

Si vous continuez à capter d'autres stations, le problème peut provenir de la force du signal de votre station préférée. Lorsque vous êtes en marge de la portée d'une station de radio, le signal a tendance à s'estomper. Vous risquez de perdre complètement le signal, ou il peut être interrompu ou déformé.

Modifier le sélecteur Local/Distant (LX/DX)

Le terme « DX » vient des débuts de la télégraphie sans fil. "DX" était un raccourci du code Morse pour une transmission distante. Le réglage DX de votre tuner FM augmente le gain du signal entre votre tuner et l'antenne.

Votre tuner est-il réglé sur LX ? Essayez de le changer en DX. Le réglage LX (Local) filtre les signaux les plus faibles et ne se verrouille que sur un signal plus fort. Basculer vers le paramètre DX peut vous permettre de verrouiller le signal d'une station plus éloignée ou de faible puissance.

Votre tuner est-il déjà réglé sur DX ? Parfois, votre radio peut avoir trop de bonnes choses. Il peut recevoir à la fois un signal local proche et un signal plus éloigné dans une bande adjacente. Ou un signal local puissant peut dominer le tuner, entraînant une distorsion et des coupures. Passez de DX à LX et voyez si votre station devient plus claire.

Modifiez vos paramètres, réinitialisez votre récepteur et réessayez de syntoniser votre station. Cette réinitialisation peut résoudre votre problème. Ou, il se peut que votre station préférée n'ait tout simplement pas la puissance nécessaire pour produire un signal suffisamment puissant pour votre tuner.

Obtenez un amplificateur de signal d'autoradio

Si votre réception globale est bonne et que vous n'avez des problèmes qu'avec quelques stations distantes, un amplificateur de signal peut résoudre votre problème. Dans de tels cas, il peut être utile d'installer des amplificateurs d'antenne cela augmentera le signal entrant par votre antenne.

Qu'il s'agisse d'un signal AM ou FM, le tuner de votre unité principale fonctionne de la même manière. Il capte ou syntonise le signal, puis l'amplifie avant de l'envoyer à l'amplificateur. L'amplificateur l'amplifie davantage jusqu'à ce qu'il soit suffisamment puissant pour déplacer vos enceintes.

But if that signal is too weak, the tuner will have trouble tuning in. The radio signal and, in effect, your music will drop in and out. An antenna booster sits between the antenna and tuner and amplifies the signal by around 15dB.

In general, the power of a signal doubles with every additional 3 decibels. A 15 dB boost means the signal going into the tuner is 32 times stronger than without the signal booster in the circuit. This power boost can mean the difference between a distorted, fading signal and clear reception.

If you live in a flat rural area, an antenna booster may distort your signal. It also will not work in “dead zones” caused by surrounding hills or tall buildings. They can amplify a weak signal but can do nothing if they receive no signal at all.

Antenna boosters amplify signal noise alongside the signal. 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 technology.

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.

Réflexions finales

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