car stereo radio problem

[123hotchef]

I guess length of cable and some crocodile clips might hold for the drive.

 

[ajlelectronics]

That's the thing it works fine at home it's only on the drives it is in and out.

The nature of FM means that you can't tell much, due to the limiter. Tune around for a very hissy station which is below the limiter for stationary testing purposes. One of the Classic FM might do, unless you can find a distant and weak regional station perhaps?

You are listening for the amount of hiss during your testing, changing. It is know as "quieting". Once you reach full quieting, you will hear no further improvement, regardless of increasing signal levels.

Another option is to go and park in a "black hole" to do your testing.

 

[123hotchef]

The nature of FM means that you can't tell much, due to the limiter. Tune around for a very hissy station which is below the limiter for stationary testing purposes. One of the Classic FM might do, unless you can find a distant and weak regional station perhaps?

You are listening for the amount of hiss during your testing, changing. It is know as "quieting". Once you reach full quieting, you will hear no further improvement, regardless of increasing signal levels.

Another option is to go and park in a "black hole" to do your testing.

ok, I drive my other vechile the sme route to work and i do not loose the stations I listen too at all.

 

[skotl]

ok, I drive my other vechile the sme route to work and i do not loose the stations I listen too at all.

Gentle nudge to my post about a CB antenna not being ideal for picking up FM radio...

 

[Kayos]

Gentle nudge to my post about a CB antenna not being ideal for picking up FM radio...

To be fair, broadcast fm is so strong you could pick it up with wet string

I use filters to block it on some of my sdr setups

 

[123hotchef]

Gentle nudge to my post about a CB antenna not being ideal for picking up FM radio...

why though I though CB transmitted on FM

 

[Kayos]

why though I though CB transmitted on FM

FM (mostly) but that doesn't affect the antenna size

27mhz is much longer than a 88-107(ish) mhz broadcast fm but as above, broadcast fm is massively strong and very wide bandwidth

Connect the cb antenna directly to the radio and see what happens, if you get a decent signal then it would suggest the splitter (duplexer/diplexer really) is at fault

 

[123hotchef]

being as I had the same problem with the factory antenna cable and the new stereo I am using now I dont think it is the cable or the splitter but I will try nethertheless

 

[ajlelectronics]

why though I though CB transmitted on FM

FM is Frequency Modulation. It how the information is impressed onto the RF carrier (by varying the frequency either side of nominal in time with the audio). FM can be used on any frequency, but sadly it has become a hijacked word to replace VHF Band II broadcasts. The important thing, at least in transmit is the resonance of the aerial. That is a function of frequency, it doesn't care what the modulation method is.

This is why "digital aerials" are nonsense. The aerial receives RF, it neither knows nor cares how the information is being encoded, so there can be no such thing as a "digital" aerial anymore than there can be an "FM" aerial.

 

[mike 109444]

Worth checking the spliter for a "fine tune" trimmer. Used to dial in the CB twig to the car radio.

 

[voipio]

It would be worth using a portable radio to listen to FM broadcast stations near/in the car, to see if something in the car itself is generating interference.

 

[dobbslc]

I had trouble with my Surf when the old aerial got snapped and I tried to replace it with a cheap Halfords one, it just didnt work!
I splashed out on a brand new genuine Toyota electric aerial in the end and it's now not to bad. I seem to remember reading something about some head units requiring a boosted signal and some not, its worth checking yours. I think my head unit can be set to either.
If the wing is rusty where the aerial mounts it will cause trouble.

 

[ajlelectronics]

It would be worth using a portable radio to listen to FM broadcast stations near/in the car, to see if something in the car itself is generating interference.

This actually has merit. It could be that something in the car is generating hash. Dashcams are well known for it. As previously advised, find a WEAK signal, below the limiter. Try the radio with a separate feed from the battery with the ignition off. Then turn on to ACC then IGN to see if the station gets worse or disappears.

 

[123hotchef]

I will have a play this week, I already ran a new negative cable to the head unit to rule that out

 

[Edward Teach]

I have always done the same with my car radio's,
Taken them out, and thrown them in the bin.

 

[123hotchef]

so update I sat in the carpark at work this morning and had a fiddle.
no not like that!
the signal does get a bit better with the engine turned off not perfect like in my other Mitsi L200 but listenable.

 

[Domdom]

Having been into the car audio scene for several decades my suggestions for testing this are simple. Back to basics.

Grab a decent FM aerial, maybe something which has a base which you mount to the wing and then a fibreglass whip which you screw on. Connect to the radio and see what happens. You should see a massive improvement, which would indicate something in the aerial connection you have is the cause. Seeing that aerial splitter I would bet this will solve the problem.

the signal does get a bit better with the engine turned off not perfect like in my other Mitsi L200 but listenable.

This. If you still have issues, then check power and ground to the radio itself, take a feed on some good thick wire straight from the battery (+ve and -ve) so you bypass any line-fitted gubbins in the supply. This can cause no end of irritations if you're not careful. Go direct to the battery, not just a convenient live nearby. You want to be away from any other bits being closer to the battery. A temporary lash up is fine as long as both ends are terminated properly. It will tell you what you need to know before you rip out the interior to run cables.
Both these things should improve matters no end. Other things you can do are to shield the head unit by using the self-adhesive copper tape on all the case joints. Solder a wire on and ground it as well.

Items to consider in RF stuff. Power interference is a real thing. A decent capacitor can help filter out noise from other electronics such as charging systems and the electronic controls for other circuits. Ground isn't necessarily ground depending where it comes from. It can have a resistance in the path back to the real ground (battery negative) if it's going through spot welded body joints etc. This is why many cars have ground straps all over the place to try and keep modern electronics all at the same PD with regard to battery ground.

I know your pain, it can be a real nuisance tracing such vague things. I have an old Nakamichi TD1200 radio/cassette which has a US spec tuner in it (much less sensitive than EU and slightly different channel spacing). Super sensitive tuner which gives concert hall levels of performance, but interference is a huge issue. It takes time to get through it all but the end result is worth the effort.

 

[123hotchef]

I shall try the cable straight to the battery and see what we get.

 

[ajlelectronics]

Back to basics.

Absolutely.

 

[slim_boy_fat]

There's 'new' and 'new to me', which category does your radio fall into?