Got a problem with your mobile installation?
ICCís resident phone doctor is on hand to answer your questions
DO OR DIY?
I want to buy a hands-free car kit for my
M-registered Nissan Micra Hollywood, but I canít decide whether to do it
myself, or pay to have one fitted. Iím quite handy with a screwdriver, just how
difficult can it be? PS, the phone is a Nokia 2110.
Mick Tilling, Southend
Thereís several DIY car kits for the 2110 on
the market, that donít even require basic screw-driving skills. Some of them
are very good, but weíd 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, theyíre usually louder,
with better acoustics -- i.e. a separate speaker that can be mounted where it
will do most good -- and because theyíre permanently installed, theyíre 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 electricís, and itís no more difficult than
fitting a car stereo -- possibly even easier -- nevertheless, weíd still suggest you leave it to the
professionals. There are a number of safety considerations, components have to
be mounted so theyíre 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
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 thereís no difference on the signal strength
meter, when itís 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 hasnít been damaged, and the cable isnít
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 youíre hand youíve 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 youíve got a glass-mount antenna,
make sure the couplers are precisely aligned; the adhesive can soften in really
hot weather, or if theyíre 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 Iím 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 Ďhot-swapí
power facilities, needless to say the 7500 isnít one of them. Itís 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 itís removed from a power source -- whether itís 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 isnít a very good
Where is the best place for the microphone in
my Fiat Uno. Iíve tried it everywhere, on the sun visor, on the door pillar,
over the door, Iíve even tried holding it, but whoever Iím talking to says they
can hardly hear me. The shop who fitted the car kit have long since gone, so I
canít take it back to them.
A. S. Manning, Tunbridge
Itís quite possible thereís 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 youíre using but most models use fairly standard miniature electret
mikes, usually connected to the main unit by a 3.5mm jack plug. If thatís 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 youíre using. It costs around £15, (order code
LB69A). If that doesnít help youíll have to bite the bullet and have the
installation seen to by an engineer.
Every so often, as Iím 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, itís held in a spring cradle, and powered by a Vocall
car adaptor cord.
Kenny Goodman, Winchester
Youíre right, the Ďwarblingí sound is coming
from your phone. Youíre 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 wouldnít hear it, the
signal is on a frequency way above what your car stereo can pick up and, itís
unusual to only hear it on one speaker, but that will have to remain a mystery.
The root cause is ĎRF breakthroughí, 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
If itís really driving you mad, then hereís
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, youíre just going to have to live with it, get a proper car kit, turn
the volume down on your stereo, or drive more slowly...
” R. Maybury 1997 2101