MOBILE QUESTIONS

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Got a problem with your mobile installation? ICC’s resident phone doctor is on hand to answer your questions

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DO OR DIY?

I want to buy a hands-free car kit for my M-registered Nissan Micra Hollywood, but I can’t decide whether to do it myself, or pay to have one fitted. I’m quite handy with a screwdriver, just how difficult can it be? PS, the phone is a Nokia 2110.

Mick Tilling, Southend

There’s several DIY car kits for the 2110 on the market, that don’t even require basic screw-driving skills. Some of them are very good, but we’d normally recommend a full kit for anyone that uses their phone in the car a lot, and depends on a good quality of contact. Full kits are more likely to have provision for an outside antenna, they’re usually louder, with better acoustics -- i.e. a separate speaker that can be mounted where it will do most good -- and because they’re permanently installed, they’re less likely to get knocked about, pinched, or have to compete with other accessories for the cigar lighter socket.

Installation is within the scope of anyone who knows their way around a car electric’s, and it’s no more difficult than fitting a car stereo -- possibly even easier -- nevertheless,  we’d still suggest you leave it to the professionals. There are a number of safety considerations, components have to be mounted so they’re accessible, and sub-standard wiring can be very dangerous. A trained engineer will know the right type of antenna for your vehicle, and where to put it, plus you will have some comeback if a fault develops.  

AERIAL ANGST

Two years ago I had a hands-free kit installed for my Motorola Microtac II but just lately calls have cut out, for no apparent reason. I have also noticed that there’s no difference on the signal strength meter, when it’s in its cradle, or hand held. Is there a fault with the phone, or the car kit?

S. Deaking, Kings Lynn

Probably neither, taking into account the age of your installation the most likely culprits are the antenna, the lead or the connectors. You should check the cable for any obvious faults; look carefully where the wire enters or emerges through the bodywork, or disappears under trim and carpets. Make sure the outer insulator hasn’t been damaged, and the cable isn’t crushed or deformed.  Check the tightness of the connectors; give them a gentle tug, to make sure the terminations are still sound, if the wire comes away in you’re hand you’ve probably found the fault... Examine the antenna, mounting bracket and couplers. Remove the aerial and thoroughly clean the clamp or mount and the surrounding area; a film of conductive road grime could be weakening the signal. Assuming you’ve got a glass-mount antenna, make sure the couplers are precisely aligned; the adhesive can soften in really hot weather, or if they’re mounted over rear-screen heating elements, and allow one or both of them to shift slightly. If none of that makes a difference then you should think about having the system checked by an engineer.

A PIN IN THE BUM

I have a Motorola 7500 GSM phone which I use with an ORA car kit. They work well together, except for one thing. Whenever I insert or remove the phone, or stop the engine, the phone switches off and I have to re-enter my PIN code. This is a real pain when I’m out shopping, when I might have to switch the phone back on and enter the code half a dozen times or more. Is there any way I can program the phone so that it stays on when I take it in and out of the car?

Jilly Frewin, Salford

Very few mobile phones have so-called ‘hot-swap’ power facilities, needless to say the 7500 isn’t one of them. It’s the price you have to pay for security. The designers rightly assume that if your phone is stolen, the thief will want to use it to make calls. If the phone cuts out whenever it’s removed from a power source -- whether it’s the battery, or a car holder -- it will be effectively useless. The only way around it would be to disable the security features altogether, which obviously isn’t a very good idea!

DEAF MIKE

Where is the best place for the microphone in my Fiat Uno. I’ve tried it everywhere, on the sun visor, on the door pillar, over the door, I’ve even tried holding it, but whoever I’m talking to says they can hardly hear me. The shop who fitted the car kit have long since gone, so I can’t take it back to them.

A. S. Manning, Tunbridge

It’s quite possible there’s a fault with the microphone, or it may have something to do with the pre-amp circuitry or connections in the phone cradle. It would have been helpful to know the make and type of car kit you’re using but most models use fairly standard miniature electret mikes, usually connected to the main unit by a 3.5mm jack plug. If that’s the case you could try substituting your microphone, to see if that makes a difference. Maplin Electronics sell a range of specialist mikes, including a tie-clip, that should be similar to the one you’re using. It costs around £15, (order code LB69A). If that doesn’t help you’ll have to bite the bullet and have the installation seen to by an engineer.    

NOISE ANNOYS

Every so often, as I’m driving along, I get a really loud and annoying warbling sound, lasting just a couple of seconds, coming from the left hand speaker of my car stereo. This only happens when my mobile phone is switched on, which leads me to think it is the source. The phone is a Panasonic G500, it’s held in a spring cradle, and powered by a Vocall car adaptor cord.

Kenny Goodman, Winchester

You’re right, the ‘warbling’ sound is coming from your phone. You’re hearing a  brief burst of data, transmitted by the phone, which tells the network where it is, as you travel from one cell site to another. Normally you wouldn’t hear it, the signal is on a frequency way above what your car stereo can pick up and, it’s unusual to only hear it on one speaker, but that will have to remain a mystery. The root cause is ‘RF breakthrough’, which occurs when radio signals from a nearby transmitter are picked and demodulated up by audio or tuning circuits. It may be that your radio has ineffective screening, or the two devices are simply too close together. Signals can also get into the stereo down the power cables.

If it’s really driving you mad, then here’s several things worth trying. Move the phone and its power cable as far away from the stereo as practical. The stereo and the cigarette lighter socket may be sharing the same live feed or earth, if so separate them and find another power take-off for the stereo; also try re-routing power and speaker cables. Failing that, you’re just going to have to live with it, get a proper car kit, turn the volume down on your stereo, or drive more slowly...

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Ó R. Maybury 1997 2101