Disconnect antenna amp better reception than when connected? Huh?

[rpm215]

2005 4Runner SE / Non JBL

I recently installed a Sony XAV-AV100 with a PAC Audio RP4.2-TY11 adapter, both from Crutchfield.

Since installing, AM reception has been non-existent, and FM reception has been spotty. Reception for both was fine on the low-end JVC unit I replaced.

I've been around the track on this a few times. Before today, I made sure the lead coming out of the head unit to power the antenna amp was connected to the harness correctly. There appears to be voltage on on these wires at the point they connect to the vehicle's harness. I also have a Y adapter cable for the diversity antenna. Still, reception issues persist.

Today I took one more stab at this, taking it all apart and testing power, ground, etc. Then I disconnected what I have been thinking all along is the harness for the antenna amp

AM reception is better. Not fantastic, but better...maybe normal (?). I reconnected, and reception dropped again. Disconnected...better reception.

I don't know what to make of this. Is this indeed the wire to the antenna amp? Why would I have better reception if I'm ostensibly no longer powering it...unless my powering it was causing interference of some sort, and disconnecting it is now giving me un-amplified reception.

Any thoughts? I was stumped before, now I'm more stumped.

 

[rpm215]

Figure this out....some power, but not enough power to antenna amp

I hooked up my old JVC radio and observed 11.5v going to the antenna amp

The new Sony had 11.5v coming out of it to power remote devices, but at the lead to the antenna it was only 9.5v. That's on the other side of the PAC Audio unit from the radio...so maybe the PAC Audio was stepping it down some how (?)

I looked on the net to see if there's any information about this, and it appears there's a way to configure the unit via PC, but I was unable to get that configuration application working. So I don't know if there'a a setting for this on the PAC Audio unit

In the end, I just bypassed the PAC Audio unit, connecting the antenna amp lead to the remote lead coming out the radio to get the full power. Problem solved.

 

[riceandpho]

wire up the antenna wire directly to the acc wire, so it can get the full 12v. you can just splice it in if your good with electrical.

 

[RTCt4r]

I messed with that connector last evening since I had read your post and was in there anyway. I had the opposite results. With it unplugged - zero AM. No question a better signal with it connected on both AM & FM.

I know that doesn't remotely answer your question tho.

 

[rpm215]

I messed with that connector last evening since I had read your post and was in there anyway. I had the opposite results. With it unplugged - zero AM. No question a better signal with it connected on both AM & FM.

I drove around a bit after my first post, and the AM reception dropped off to near 0 once I left my driveway. So I must have been getting a lucky signal bounce getting reception with that lead disconnected. That's what got me back in there the next day.

 

[simple]

wire up the antenna wire directly to the acc wire, so it can get the full 12v. you can just splice it in if your good with electrical.

The acc wire? I tried that, but when I connected it, the radio turned on despite the car not being on. I’ve been meaning to ask you again for ideas. I know the antenna is getting power because when I disconnect the power and wire, the reception noticeable drops. But even connected, my radio reception is hot garbage over 89.whatever

 

[riceandpho]

The acc wire? I tried that, but when I connected it, the radio turned on despite the car not being on. I’ve been meaning to ask you again for ideas. I know the antenna is getting power because when I disconnect the power and wire, the reception noticeable drops. But even connected, my radio reception is hot garbage over 89.whatever

4runner need to have a good 12volt source to power the antenna , even tho you use the motorola Y adapter and the gm fm adapter to the standard fm plug.


for me, i traced to that plug, then stripped a little of the insulation off the wire and tap the wire directly to a good 12v that is only on during accessory. but since i have mulitple amps, i use a relay in my remote line. it just a better way to give a good switched 12 volts.
radio signals have become a little spotty lately since last year, even when im in another car with hd radio, i just think its a little too much interference with wifi and other things.