Car Radio Reception

It seems your antenna is not correctly connected to your radio, or has some problem regarding signal isolation/noise. You may think its strange, but a friend of mine had ECU interference due to a radio installation (in that case, it was the radio itself with bad quality components...). Double check antenna cable. Have replaced ignitor plug cables recently? Are them from the noise supression type? This used to ake difference too in older models.

Nah radio is good quality or so I believe. I haven't done any work to the motor at all, bar normal lube which I do myself. Is it worth replace the whole antenna and cable?

"...Is it worth replace the whole antenna and cable?"

Yes but that should be the last resort. First, check for any loose connection at the antenna pole receptacle through the feed cable and the connector to the radio. This is best checked via a continuity test with a multimeter. Also ensure that the chasis' of the radio and the car are having good contact.

Cheers,

ethobil

Compare the two antennae between the old car and the new car. What are the size and shape differences, if any?

There is often a tuning screw adjustment for the medium wave (AM) antenna. Find your manual and locate then try adjusting the antenna matching before spending bags of money buying stuff you possibly don't need. Have FUN! TT3

EXACTLY Right, this is almost certainly the resolution.

If you think M.H. is right then give him a Good Answer!

I won't argue with either of you as it HAS been quite a long time since I installed a new radio in a car. Time waits for no man and I certainly have not been active in this particular market for a good while.

Have FUN!
TT3

Doesn't the AM band use an internal antenna of the radio? I think the external antenna is only used for the FM band.

If you are gettng engine noise in your radio, I would suggest supplying a frame ground to your radio (versus the one you have chosen) and then possibly looking into a noise filter from alternator noise. Depending on the vehicle, you should not receive alternator noise unless you have a problm with the alternator.

car radios never use an internal antenna. They are caged beasts, Faraday style.

The antenna tuning is important, the signal strength can vary ten fold with the tuning sluf. Use google, see if you can find the book on that radio, or ask an installer....unless they are looking for fees for knowledge?. This alsosounds like you have an antenna short. That will cost you all or part of the signal.

try an ohmeter

Sometimes the rear window demister element doubles as an LF and MF radio antenna.

Where the heck is the MF antenna?

(Why do people insist in tempting me like that?)

Bob, the Medium Frequency antenna is the one that sticks up off the windshield pillar, the fender or the roof. It is also usually combined with the FM antenna.

Now, go back to sleep and leave us alone!

TT3

Oh Medium Frequency antenna I thought you meant something else.

I like your 3 stooges" go back to sleep" reply; but, stay out of the business of Liberalism: don't tell me how to respond! Being from Texas, I wouldn't have expected this! Are you a transplant?

Questions:

What are the year and model differences in cars?

Where are the antennas mounted in both cars and what types are they?

What radio type are you using...analog or digital?

Who built it?

Which of the radio bands are you complaining about mainly?

Analysis based on your input: Bad antenna and possible bad grounding in external type antenna...not windshield.

Rules to remember:

FM travels in a straight line...thus signal subject to breakage receptions.

AM bounces off the Ionosphere...subject to antenna not being blocked by tunnels.

AM subject to electrical impulses interference.

AM antenna should be extended all the way up (54" is the Scientific rule)

FM on averages should be short..hence...BUY a semi-automatic antenna controlled.

Or if you can HAND-adjust a manual type...tough in ominous weather however.

BOOSTERS are fake per se...they just amplify the noise inherent in receptions.

An antenna cable should be of good design with materials and correct ohm.( i like 80)

Antennas need GREAT grounding....no corrosion or rust also.

Glass antennas are normally amplified... and subject to break.

Selectivity and sensitivity numbers are also important...but that's another discussion.

When you have NO AM reception with a MANUAL or ELECTRIC antenna...8 out of 10 its a defective antenna mast.

2 out of ten is bad grounding or bad cable.

You DID plug it in yes?

so...other than that...move to flat country land for best receptions.

What are the year and model differences in cars? Old = 1990 Diahatsu Charade

New = 1999 Ford Festiva

Where are the antennas mounted in both cars and what types are they? Both mounted in RH front door column coming out through the roof.

What radio type are you using...analog or digital? Not sure, analog I think. Australia has only just gone digital in the last month.

Who built it? JVC

Which of the radio bands are you complaining about mainly? AM. FM is OK.

Check to see if all ground straps on the car are in good shape, this could induce noise into AM band. There should be several bare braided ground straps on any vehicle. Also as a test, get a standard car antenna and just plug it into the radio and hold it outside of the car to see if anything changes. You also could be getting "ripple" off the alternator, which is coming in on the 12 volt power line...try a power line filter.

Most AM radios have an antenna tuner capacitor. The OEM radios normally have them near the antenna jack. Once cassette players came around, some had the tuner capacitor inside the cassette door off to the side. Some had tuners under the knobs.

You need to find out from the mfr where the antenna tuner capacitor is.

Since the reception is worse only on AM, and not dead, then it points to antenna tuning which is not as critical on FM because of the frequencies involved.

As you can tell from the many varied answers you got, any one or more of which may be the correct approach, this can be caused by many many problems. Take it to a sound shop which specializes in autos and let them have at it. But, beware some of these shops are nothing more than stereo installers who will just try to get you to replace the radio with a 1000 watt boom box. If that is what they advise, thank them and leave for a different shop.

I was a car stereo installer for 10 years , you probably have a bad antenna in the new car. The pillar mount antennas go bad quite often . They are inexpensive and easy to replace . Check for corrosion at the radios cable connector make sure its clean. There have been no ant. adjustment pots on radios for many years as they are all electronic now.

I assume you wired the unit correctly , double check the power wires and ground it properly.

Happy trails.

Lots of good replies (a couple of really duff ones too!!).

By now you should have realized that, providing you did not damage the radio when you took it out and then built it in the new car, that its the antenna in the new car that is causing all your problems, including the interference as well (its going into maximum amplification of the input signal and catching your ignition/computer as well).

If you have a rear window heater as the antenna, you may need a special booster to get a reasonable signal.

I would fit a proper retracting aerial and use the coax cable to the rear window to save running a new one (after checking that its OK)....or run a new coax yourself. You may need to add a control wire to raise and lower the antenna when needed....