ThomasShawn

997 TT with Bose. Crutchfield has their version of nav-tv unit for half the price. Works incredibly well but I noticed I have no or minimal FM radio reception since installing aftermarket head unit. I found somewhere a post about needing to wire 12v power to the wire for the antenna amplifier to get the best reception. I called Metra(Axxess) the makers of the harness I used and they said to run a jumper to the white wire in the harness that was the amplified antenna. However, if it’s the same wire I’m thinking of, that wire, I thought was 12v power, because that’s what I tied into to wire the tranzit blue I had in previously.

see 4th pic in this post.Tranzit blue install

so what wire is the amplified antenna ? Currently I wired the blue “antenna” wire directly to 12v and that significantly improved my reception but it’s not as good as with old PCM. The reality is I’m probably NEVER going to listen to the radio but I do want to have it hooked up correctly.

thanks

if you have FM bad reception after replacing the PCM. see my post below. I found the solution.

ThomasShawn

Petza914

I can't help with your question or how you'd look up the spec for the FM Sensitivity rating of the PCM radio, but it's possible the new head unit doesn't have as good an FM sensitivity and the reception may not be as good as with the PCM even if hooked up correctly.

ThomasShawn

See the attached image. This wire is the wire that powers the antenna amplifier.
when the original PCM is installed accessory power comes out of the PCM and powers this wire. (that's why it works as a source for power for the Tranzit Blue). But once the PCM is out there is no power to that wire. So I confirmed with key/radio on there was no current in this wire. then tuned to a station I knew worked but I wasn't receiving, I touched this wire with 12v from the accessory power off the radio and immediately I had crystal clear radio. removed-static. replaced-radio.

So, I ran a short jumper from accessory power that powers the radio to this wire. ( I didn't remove it from the harness, I just spliced into it.) now I have radio reception as good, or better than with PCM.

Hope this helps someone ele with poor radio reception or static after putting in an aftermarket radio.

Shawn

flvraptor

Recently had a shop install an aftermarket radio with CarPlay. I didn't notice the problem until I was halfway home when I tried to switch to radio. I called the shop and they said they might have to install a booster or another antenna. Before I went back to the shop which was over an hour away, I did some searching and found this thread. Spliced a switched power wire to the white wire in your picture and everything is good.

Thanks,
Pedro

shyamvenky

Does this mean that all PCM 2.1's have amplified antennas? Most of the HUR kits use/suggest a standard metra euro antenna adapter that doesn't have the power wire (at least that's what I used).
Maybe I should open up the dash and fix this.. but I'm too lazy now, and don't listen to radio that much.
But this is definitely good info to know. Thanks Shawn

oronymo

I had the shop install my Alpine HU using th Bose nav tv MOsT adapter. I know there was a radio antenna adapter but don’t think any power was hooked up. I had some but very poor radio reception. I took it back in for that (plus and adjustment to backup camera) and the guy said it’s bdcause the window antenna is really weak and he actually just spliced in a strip of wire into the antenna plug - effectively makingbthe wire the antenna. Funny thing is it kind of worked. Although reception is still worse than if was with pcm.

I bet this power wire tap in is ghe trick. Funny that none of these adapters have this.

Getting the unit out and back in again is tricky.. debating whether it’s worth it but now I know how!

ThomasShawn

yes i think it's more than just a a "wire" being used as an antenna it's actually powered antenna for better reception and for me adding that power wire made all the difference. great reception now on radio

Dripola

Thanks for this, was wondering what the fix was. One day I’ll go back in and fix the radio.

oronymo

It looks like my Alpine actually has a “power antenna” wire (blue). So I should be able to use that without splicing into the 12v line, right? Or is this only for those motorized antennas (Eg will this wire send actual constant power or is it just a “trigger” to activate a motorized antenna?)

And this would go to the vehicle plug white wire? Does anyone have a picture of this connector?

vern1

Yes this is what i was referring to in the other thread. The blue wire from the HU taps in to the white wire in the cars power harness as shown above - its as simple as that. You can hear the antenna deploy when its tapped in or at least i could

oronymo

hear it “deploy” ?

lou-in-nj

The "Power Ant." lead should be constantly powered anytime the radio is on. On my 2006 997 I used the PCM adapter from Spiral Audio, and I didn't have any extra wiring to do or issues with reception. Furthermore, I think the reception is at least as good as the original radio.

vern1

Yes, when i tapped in to the accessory power wire (white) i heard a mechanical sound like the antenna was deploying, kind of like the old power antennas that used to deploy out of bumpers. Maybe it was something else but i dont recall hearing that sound before i tapped in to that wire.

vern1

Yes but many dont have the adapter you used and that was really hos question as to how to get it properly set up. As with mine, i had to tap the wires together. Its not constantly powered until you do this