powered antenna : draining battery - ideas?

Bukowski · 04-06-2017, 06:08 AM

On a separate thread, I've been investigating a battery drain problem. I think it is due to the powered antenna.

Just to be clear - because this is a serious problem for Googling this - this is NOT an "aerial", a "power antenna" that moves up and down, or anything like that. It is the antenna that originally was embedded in the windshield. A user - I'll try to find the post - wrote up a nice how-to to run some plain or insulated wire around the edge of the windshield to get some AM/FM reception. I contributed to this discussion.

back to the battery drain : I am wondering what to do here? Is the powered antenna - even if brand new - going to drain the battery? Is there a relay (I found none)? Are there good after-market powered antennas? When the powered antenna is detached, the AM/FM is practically non-existent. I suppose I could unplug it every time I turn the car off, but that's a nusiance. I assume the radio unit itself is OK.

Is there a test on the powered antenna itself which will reveal a specific reason it might drain the battery?

thomasryan · 04-06-2017, 06:16 AM

the antenna amplifier is powered from the stock radio plug that should only be powered with the radio on.

is your radio stock? you could use the amp trigger if you have an aftermarket radio.

Bukowski · 04-06-2017, 06:59 AM

Not stock - 90's era Alpine.

What's /where's this amp trigger?

v2rocket_aka944 · 04-06-2017, 07:27 AM

I have a cheap Sony head unit and a simple wire run around the perimeter of my windshield as antenna.
I do not use/have installed the antenna booster and have no problem with radio reception.
My wire is just spliced onto a normal antenna plug (with a ground to the chassis behind the dash) into the back of the radio.

thomasryan · 04-06-2017, 07:27 AM

It is the blue wire on this alpine cda-9811 I have sitting here. Check the sticker on your unit.

Bukowski · 04-06-2017, 11:28 AM

Quote:

Originally Posted by thomasryan

It is the blue wire on this alpine cda-9811 I have sitting here.

While I'm looking into this - can you tell me - what's the idea here, to attach the blue wire to ... to what?

thomasryan · 04-06-2017, 03:15 PM

I was assuming that you have the in glass antenna. Connect the blue amplifier trigger of your alpine head unit to the power amplifier for the antenna amp up behind the glove box.

Bukowski · 04-06-2017, 05:14 PM

Quote:

Originally Posted by thomasryan

I was assuming that you have the in glass antenna. Connect the blue amplifier trigger of your alpine head unit to the power amplifier for the antenna amp up behind the glove box.

Thanks

Pretty sure I did this though - huge difference in AM/FM reception.

However, I think there's another wire that isn't connected to anything... I need to dig deeper...

Bukowski · 02:46 AM

specific antenna links - thank you 777 for getting me on this track!

windshield without antenna? No problem

radio antenna

... in the first link, scroll all the way down - there's a home-made jumper I created in between the blue lead from the Alpine and the black female plug from the antenna amplifier (getting with the proper terms here finally). and I quote :

"the detached wire goes to one of those stiff black wrapped bundles and curls around somewhere, maybe the remaining Blaupunkt wire harness"

... and this quote-of-a-quote of the other link (the classic 924/944/968 Stereo FAQ):

"Note that the preamp must be connected to a switched source to avoid running the battery down. Again, this is the 'power antenna' lead in the radio's wiring harness."

... you see what kind of brain I have. anywho - I think this makes it 99% certain - battery drain due to antenna amplifier.... buuut I still don't see - the blue wire is connected to the female black wire - that's how its supposed to be... to be switched... I'll double check the Alpine - perhaps the Alpine is NOT switched?...

Bukowski · 03-17-2018, 06:00 AM

supplementary info:

during the period of this problem, there was a loose alternator belt. In addition, a voltage drop test showed that the battery cable was having problems, or the engine grounding stud. See this post for more detail:

Electrical / starting problem

in short, I think this problem would go away - but still drain the battery - now that the alternator belt and battery cable are good.