Electric aerial

Post Thu Jan 24, 2013 5:45 pm

Hi All,
I have fitted an original electric aerial as well as BMW Bavaria Business RDS radio to my beloved 318.

When I turn on the car and then the radio the aerial goes up and that's fine, when I furn off the radio the aerial goes down
and that's fine again.

But when I turn the car off but not the radio the aerial doesn't go down. Is this normal?

thanks for any input.
Cheers, Peter.

Post Thu Jan 24, 2013 6:08 pm

Mine does that too, not sure if it's normal though...one annoying thing I have is that even when I'm just listening to a CD the aerial remained up...not sure if it's my wiring, or the head unit.

Post Thu Jan 24, 2013 6:25 pm

Does the aerial go up when you start the car but the radio is off?

Post Thu Jan 24, 2013 6:36 pm

IIRC the power feed for the aerial comes from the head unit - Radio on regardless of whether the engine is running or whether you're listening to the radio or tape/cd the aerial will be up as its receiving a 12v feed from the head unit as soon as you switch it on.

Post Thu Jan 24, 2013 7:37 pm

B7 wrote:Does the aerial go up when you start the car but the radio is off?

No.
The aerial only goes up when the radio is switched on.

Post Thu Jan 24, 2013 8:05 pm

bmw335icoupe wrote:
B7 wrote:Does the aerial go up when you start the car but the radio is off?
No.
The aerial only goes up when the radio is switched on.

See my post

The when you switch the head unit on that sends a 12v feed to the aerial which sends it up - and vice versa when you switch it off.

Post Thu Jan 24, 2013 8:33 pm

There are two live feeds to the aerial, one is permanent from the battery and the other is switched from the radio.

They are the wrong way round.

Post Thu Jan 24, 2013 8:35 pm

in other words, all is fine....

Post Thu Jan 24, 2013 10:19 pm

I have my aerial disconnected and permanently down. The radio sucks and makes you feel schitzo with all those voices constantly talking garbage... argh.!

Post Thu Jan 24, 2013 10:35 pm

bss325i wrote:There are two live feeds to the aerial, one is permanent from the battery and the other is switched from the radio.

They are the wrong way round.

That could also explain why the battery goes flat after 5 days.
Am I correct?

Post Thu Jan 24, 2013 10:47 pm

bmw335icoupe wrote:
bss325i wrote:There are two live feeds to the aerial, one is permanent from the battery and the other is switched from the radio.

They are the wrong way round.
That could also explain why the battery goes flat after 5 days.
Am I correct?

Possibly.

Connect a meter set to amps between the negative cable and negative battery terminal and see how many amps current drain you have.

If its over 50mA (0.05amps) then you have an excessive drain. Disconnect the aerial and see if the drain drops.

Post Thu Jan 24, 2013 11:07 pm

capri_rob wrote:IIRC the power feed for the aerial comes from the head unit - Radio on regardless of whether the engine is running or whether you're listening to the radio or tape/cd the aerial will be up as its receiving a 12v feed from the head unit as soon as you switch it on.

The only car I've had with a working electric aerial only put the aerial up when the radio was on, was down when using any other input on all the headunits I used in the car.

Post Fri Jan 25, 2013 6:47 am

Kedge wrote:
capri_rob wrote:IIRC the power feed for the aerial comes from the head unit - Radio on regardless of whether the engine is running or whether you're listening to the radio or tape/cd the aerial will be up as its receiving a 12v feed from the head unit as soon as you switch it on.
The only car I've had with a working electric aerial only put the aerial up when the radio was on, was down when using any other input on all the headunits I used in the car.

The headunits I've had have all been more basic than that - just one feed switched from the HU that became live as soon as you turned the HU on.

Wasn't aware until Baz's post that there was a second live feed