Technical Aerial

[karm777]

Hi all, can anyone tell me if Evo has an amplified aerial, if so how can I switch this when installing an aftermarket head unit.
Also is there anywhere I can get a wiring diagram for Punto Evo showing stereo connections.

 

[Mkala]

Hello,

Punto have amplified aerial.
Since Evo, it seems to be switched on/off via CAN bus, the headunit have to do this.

About all people that installed an after market unit have reception issues, so don't know how you could control antenna amplifier.

You can find wiring informations on the forum, a lot of picture of original unit with sticker on it, indicating connections.
If you find a solution keep us informed

 

[karm777]

Thanks for reply. Does anyone know where amp is situated, behind unit or in headlining etc...

 

[Mkala]

You welcome

Not sure, but it should be in the base of antenna, inside the car, between the sheet metal of roof and headliner.

Edit : according this item amplifier is integrated into original head unit :
http://www.ebay.ch/itm/CT27AA14-Fia...2?pt=UK_In_Car_Technology&hash=item43c1777010

But no experience with this, I keep original radio.

 

[karm777]

Again thanks for response. I have fitted one of these boosters and it does improve reception a bit , but not as good as original radio.
I shall keep trying .

 

[Mkala]

Okay, two possibilities : replacement amplifier does not perform very well or if it is behind the original amplifier which is not powered... this not solve the problem, clean signal can't com from antenna.

Do you have blue and me ?
I found this for the Grande Punto (don't have documentation for Evo), but it should be the same except Evo amplifier is activated via CAN bus :

Aerial The monofunction (radio only) aerial support, located on the roof of the vehicle at the rear is the "separate supply" type because it has two connecting bridges (coaxial radio signal transmission cable and power supply line).
The monofunction aerial stem is 36 cm long.
The support is marked by a coloured seal to which the stem of the aerial is tightened with a flag of the same colour to prevent different types from being fitted.
The coaxial cable has an extension included in the vehicle rear and dashboard wiring which reaches the radio itself.
In the case of the Bluetooth hands-free option, the aerial is the Phantom Power type.
It has only one connecting bridge for the radio aerial (a coaxial cable for the power supply and transmission of the radio signal).

 

[karm777]

I have blue and me. It seems that when original unit is powered on there is 12v being sent to the centre of the coax. I assumed this was to power the aerial amp so on my replacement head unit I introduced 12v to the centre, but all I got was interference with the signal.

 

[Mkala]

Ok... strange, I understood thing like you, but it seem it does not work like this.

Can you measure voltage DC on coax on your original unit ?

 

[karm777]

I think it strange too. Voltage was just over the 12v mark.

 

[Mkala]

Really, it looks it's the car battery voltage.

On the original unit, you did the measure :
- between the center coax and coax shield, how many volts ?
- between the center coax and radio case, how many volts ?

If you measure resistance between coax shield and radio case, it's short or open ?
Just to know if supply to antenna provided is isolated or not.

The other possibility is the new radio unit don't like at all power goes in on antenna side (be careful, don't break anything).