Hello,
My recently replaced Ford 6006 unit had pretty good AM reception though sometimes would generate a ssh ssh ssh type of interferance (usually on 5Live 909 MW) which strangely could be reduced or cured temporarily by using another electrical device, the best bet was a quick tweak on one of the electric seat adjusters, not enough to move the seat even though clearly enough to generate some load.
The newly fitted Pioneer MP3 unit exhibits simlar charateristics on occasions though more a warbling than the previous ssh ssh though it is also reduced by a tweak on the elec seat as before.
This perhaps indicates a slight supression problem, any ideas?
Thanks.
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I had something similar in an old Seat Ibiza Cupra, tried putting a supressor on the alternator which helped a little bit but the only way to cure it was to take the positve supply straight from the battery terminal. I.e fit yourself a new cable and crimp it to the battery +ve terminal. Then take a ground point from somewhere as clean as possible, in my Seat there was a shiny screw attached straight to the Chassis by the door pillar.
Suppression is really awkward to route out, it could be anything resonating at that particular frequency. It's down to the manufacturer to ensure the supplys are clean, obviously Ford didn't bother!!
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"I.e fit yourself a new cable and crimp it to the battery +ve terminal. Then take a ground point from somewhere as clean as possible, in my Seat there was a shiny screw attached straight to the Chassis by the door pillar."
But put an in-line fuse in the circuit.
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Yeah good point Geoff!!!!!
Thinking back the Pioneer Head Unit I fitted actually had an in-line fuse on the +ve cable so I was lucky.
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>>fit yourself a new cable and crimp it to the battery +ve terminal>>
Thanks though I need it switched with the ignition?
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>>fit yourself a new cable and crimp it to the battery +ve terminal>>
> Thanks though I need it switched with the ignition?
Use a relay. your current power feed to the radio powers the relay which switches the live feed from the battery.
I would use twin core twisted power cable onto negative and postive of battery (inline fuse on both neg and pos)
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TourVanMan TM < Ex RF >
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Yes, leave that feed alone, just take the main supply feed from the battery. As soon as the Ignition feed is high it's irrelevant if this has noise on it or not!
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If the interference is coming from the alternator or HT (does it do it with the engine off?) it will change in pitch as the engine speed increases. You can reduce the interference by sticking a nice fat electrolytic across the +ve supply and ground as near to the unit as possible.
If the interference is not engine related or only heard on AM, then it's most likely your aerial or cable that is not up to the job. Signal boosters can sometimes help but the best option is usually to replace the aerial and cable for something better.
Kevin...
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I improved my AM reception by removing the aerial and cleaning the male/female threads on it.
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I think jc2's suggestion is a good one - quick, cheap, and simple. AM is much more susceptible to noise, and so, anything you can do to increase signal and reduce noise is a good thing.
As the main cause of the noise is the alternator, and changing the alternator electrical loading changes the noise, I would put an oscilloscope across the battery, and see what the alternator waveform looks like under different load conditions. If you see spurious spikes rather than a nice ripple, the alternator may need some work - although you may also need to check out the regulator - is this within the ECU on your car?
I would hesitate before hacking the wiring around - I suspect that this is akin to treating the symptom rather than the disease.
Number_Cruncher
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A lot of people put Studlock,threadlock or similar on their aerial;don't if you want any AM reception-it virtually destroys the signal-your wife won't be able to get the Archers.
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NEVER put fuses in the negative wire, (unless you have a +ve earth car) they serve no safety function and increase the resistance, which is the source of a lot of radio problems.
IF you put an electrolytic capacitor in the car, it needs to be rated at at least 25 volts, and if you wire it up the wrong way it will explode in your face.
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>IF you put an electrolytic capacitor in the car, it needs to be rated at at least 25 volts, and if you wire it up
>the wrong way it will explode in your face.
Good warning but a bit dramatic.
The bigger smoothing capacitors are usually rated at a minimum of 63v these days and have either a vent hole or deliberately weakened top cap (cross cuts) to prevent anything more explosive than a pffutt when they fail.
I seriously doubt that the interference is being injected through the power supply though. Much more likely to be the aerial or cable.
Kevin...
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> NEVER put fuses in the negative wire
if you are wiring a negative wire back to the battery (and you should if you want pure clean power) ALWAYS put a fuse int he negative wire. If you dont and the engine to earth strap gets a bit iffy you could have 300 amps coursing through your stereo. It wont like it
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TourVanMan TM < Ex RF >
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Two points which might help.
1- I used Studlock on an arial before a trip to France and found that I could not get LW reception in areas I previously could - No Test Match !
2 - I put capacitors around the eletrical system in the way you did on 70's cars on a modern car to improve things with DISASTROUS results on all manner of sensors and functions - needed a visit to a dealer and some downloads to put things right - red faces all round!
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Thanks for all of the replies:
>>It's down to the manufacturer to ensure the supplys are clean, obviously Ford didn't bother!!>>
>>If the interference is coming from the alternator or HT (does it do it with the engine off?) it will change in pitch as the engine speed increases.>>
It is not HT because it is a diesel and is not engine speed dependant.
The problem is only apparent when the signal is weak, when the car is moving the interferance is a kind of warble (previously a ssh ssh with the old unit), yes it does it when the engine is off (if the signal is weak) though it is more of a constant level of interferance when the car is not moving, sometimes the reception can be great though going through a village between buildings causes the interferance.
>>As the main cause of the noise is the alternator, and changing the alternator electrical loading changes the noise,>>
Interesting this because, yes, it does change the noise though more specifically it reduces the noise and has a longer term effect even though the loading is instantaneous.
I remember i had a company Vectra that needed a new aerial amp (IIRC it was in the roof below the base of the aerial), I am wondering if this car also has a similar amp which assists in the event of a weak signal, perhaps this amp is failing though changing the electrical load has a benficial effect, need to think more about it to work out how this might be the case.
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I assume the aerial amp is fed by voltage up the lead? (there will be a dongle in the aerial feed or plufg to do this? If so this needs to go back to the battery as well (again fed through a relay)
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TourVanMan TM < Ex RF >
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