Technical Adding an aerial, Sei only has blanking plate

[YoungButVintage]

I'm on a mission to add a radio to my Seicento Young 1999. I'm not sure about the aerial. This car never had one, just a blanking plate. Removing a plastic bolt reveals a female thread. Is it possible to add an aerial by screwing into this thread, or will I have to remove the whole blanking plate and bolt a new aerial on from underneath? Will any aerial do, or must it be a dedicated one of some sort?

 

[the green vanper]

If you can see the copper or brass thread, there should be a coaxial cable connected with the other end somewhere behind the dash.

Best antennaes are a fraction of the FM wave, which is around 3m (12 ft). 1/4 of the FM wave would be 77 cm. They were standard on the Cinquecento and 126p as far as I remember. The seicento had already a shorter antennae:

In ePER:

If I understand it correctly, there should be the cable number 3 installed, as it is not marked as an option.

The 11 - 12 - 13 are for the E833 option, which is the mobile phone predisposition.

Can you post a photo of what you have on the roof?

 

[YoungButVintage]

Thanks for the reply. Yep, I believe the feed from inside end of roof plug to radio area is there, as there's a wire with an aerial plug behind the space for the radio.
This is what's at the roof, with the small plastic plug unscrewed from the centre. It looks like there's a female metal thread to me. I can't think why they would have a plastic plug to unscrew from the top unless it's for attaching an aerial. But the aerials I've seen look like they have baseplates that don't have space underneath to go over my plug. Maybe I'm wrong. It's about an inch across.

 

[the green vanper]

Looking at it and at ePER I'd say it's the part marked 10 on the above diagram. It looks like that:

That's a diagram showing the parts:

This looks like the original base:

https://allegro.pl/oferta/podstawa-anteny-gniazdo-antenowe-fiat-ducato-doblo-fiorino-oryginal-15040026263

However I think it has to be dismantled, there is a rubber seal on the bottom. Taking it off should reveal the inside and give you an idea of how it should be installed.

The aftermarket products can have the same thread but different way of installation.

I'd contact the seller and ask for details.

 

[the green vanper]

I've just found more photos of the support:

The part marked with the arrow looks same as the one on the original base I've linked to earlier:

I assume the support needs to be unscrewed and the base need to be screwed in the same place. But as stated before, perhaps the original base has the same support inside.

I'd personally go for the original one

+ the antennae itself:

https://allegro.pl/oferta/antena-samochodowa-radia-fiat-ducato-fiorino-doblo-i-seicento-brava-marea-16724637975

 

[YoungButVintage]

Interesting. Your diagram sposób montażu seems to show a baseplate fitting over my plug and screwing in from above. Which may be hard to get hold of. I'll see if I can find it.
PS thanks for Allegro links. I'm in Poland, and enjoying the parts availability!

 

[YoungButVintage]

Actually, the allegro listing for the grzybek, blanking plate, says it's to allow connection for f an aerial, which supports my above theory...

 

[the green vanper]

Thought about it, too. But the diagram doesn't have to be from the original element.

However the original base does not seem to have a cover for the this screw. That's why I suggested contacting the base seller to have more details.