Folks with newer head units such as the Bolero and Columbus that have the diversity function requiring 2 antennae, on a MkII Octavia for example, where's the second aerial?

Ta

Edit due to confusion! They both run through the roof mounted antenna I think?

Is there an existing connection to this if you have a Stream HU fitted? Does the roof aerial have any function?

+1

Second aerial is not really needed on the Columbus - just remember to plug the single aerial into the socket nearest the GPS plug to get a better signal and TMC. It will fit without adapters (at least mine does), but it will generate an error code ('Open circuit fault') when scanned with VCDS.

I'm told, but have not tried it, that one of these off eBay will overcome that issue if you are worried about it.

If you do have two aerials, then you will need one of these in order to be able to plug them both in.

It's for my RCD Karl but I expect the same principle applies, which is to only plug into one of the inputs (one does AM/FM and one just FM, right?).

I've seen the Diversity adaptors, but had also been told (whether this is right or not, I do not know) that the system is likely to have a paddy as it reads the same signal twice and not two different signals from the two antennae.

I don't have two aerials at present as the Stream does not require them, but wondered if the second aerial is present as part of the loom or the fitment of glass or if these are added specific to the car build.

KL's post (#2) suggests that both aerials are in the rear screen, which on a MkII would presumably void the requirement for a roof aerial.

The RCD510DAB I am attempting to fit has a connection for Diversity as well as DAB and I am just trying to settle on the right aftermarket aerial.

It's for my RCD Karl but I expect the same principle applies, which is to only plug into one of the inputs (one does AM/FM and one just FM, right?).

The one nearest the outer edge of the unit (on Columbus) does AM/FM the other one does FM & TMC. It also has (in my case) slightly better FM reception.

I've seen the Diversity adaptors, but had also been told (whether this is right or not, I do not know) that the system is likely to have a paddy as it reads the same signal twice and not two different signals from the two antennae.

I've been told they work, but I've also heard the same. As I only have one aerial and have managed to bypass any adapters, I'm quite happy at the mo.

I don't have two aerials at present as the Stream does not require them, but wondered if the second aerial is present as part of the loom or the fitment of glass or if these are added specific to the car build.

KL's post (#2) suggests that both aerials are in the rear screen, which on a MkII would presumably void the requirement for a roof aerial.

My pre-FL '07 Octavia only has a roof mounted 'whip' aerial - no rear window aerials and no second aerial so doubt yours will have wiring for one fitted as standard. I believe, by will stand corrected if anyone knows better, that the rear window aerials were only FL Octavias factory fitted with Columbus (navigation) units as the roof 'aerial' was used for the GPS unit and the GSM (mobile phone) aerial.