453 Fortwo Roof Aerial

A common complaint on the 453 fortwo is that the radio reception is shit. However, it’s ok on the 453 forfour.

Why the difference? Well, it’s not something that fortwo owners really notice until you point it out.

Tell them to point at their aerial. They’ll turn around and if they owned a previous fortwo, they’ll immediately look in front of the nearside wing mirror before realising it’s missing. They’ll then look on the roof, notice that it’s not there either and just assume it’s some clever windscreen mounted antenna.

Well, it’s not. Smart/Renault (probably just Renault) decided that, because the panels were plastic, it would be ok to put the antenna underneath the nearside front arch panel. The issue being that, as it’s so low and backed by the steel cage of the car, actually accessing an FM signal is tricky. Unless you have a very strong signal in your area, the reception usually sucks.

The reason that the forfour reception is OK is because it has a proper roof aerial, like a real car.

Fitting A Roof Aerial To The Fortwo

This is a really scary project since screwing this up means you’d need a replacement roof. You’ll need to mark a dot.

Make sure it’s in the centre or it’ll look terrible.

Measure from both sides and double check before getting your drill out.

Because of the roof liner and interior structure, you are limited to how far back you can put the hole.

I went with 19.5cm from the back edge of the roof. This just clears everything on mine. Double check on yours.

This is the aerial I used. It’s just an FM/DAB aerial that I bought from eBay. To be honest, I wouldn’t recommend it. There is a better option which I’ll mention later on.

Work out what part will go into a hole…

…and measure it so you know what drill to use.

On the inside rear of the roof liner are 2 indents with…

…2 push in clips.

Pull these out so you can pull the roof liner down enough to work between the roof and the headliner.

Since you won’t have a drill big enough, I recommend getting a stepped drill bit.

No going back now! Notice that this is the opaque roof and the whole thing is about 7mm thick. However, if you have the clear roof, it’ll be thinner. The thickness of the roof caused issues that I had to bodge around.

Post the wires through.

Thread the wires through the seal and nut.

This is where the roof thickness caused issues for me since the aerial base was obviously designed for a metal roof.

Generally, normal car roofs are 1mm to 2mm thick. So there wasn’t enough thread on the aerial base for the nut, toothed washer and seal to catch on to. I had a little panic but eventually deconstructed the nut to make it flatter.

Pull the wires through.

To be double sure, I squirted a bit of black silicone sealant under the aerial base in the hope that it’d help create a seal.

In an attempt to stop the nut undoing, I placed some threadlock onto the thread before tightening it up.

I used a 21mm rings spanner but your nut may be a different size.

The rubber boot seal can be pulled off and the wires can then be offered down the side and into the boot.

The next day, I was glad to find out that it was nice and secure.

Issues And Further Ideas

As I said before, this aerial was for FM and DAB and had a separate lead for both. The issue is that it also had a power cable that requires a switched live. I’m assuming it’s an active/amplified antenna. It’s only the next day it occured to me that there was no earth cable. Then I realised that on a normal car, the roof is metal and earthed. The smart’s composite roof is not metal or earthed. Bollocks!

So, if you want to use an active aerial, a large square of sticky backed copper stuck under the roof could be connected to a wire and that wire then earthed. Giving the aerial  an earthed surface. If you can find a ring terminal big enough to go around the thread, that would also be a good option.

Forfour Roof Aerial

That’s when I thought I’d pick up a 453 forfour roof aerial. There are 2 options. FM only or FM and DAB. You can tell the difference by how many cables it has. These are not active so don’t need earthing. FM only has 1 cable with a cream coloured Fakra B connector. Aerials with DAB as well also have a nut brown Fakra F connector.

The issue still remains that the forfour roof is 3mm thick plastic so it’s still not designed for the thick opaque fortwo roof. I would recommend searching for an antenna designed for a thicker roof.