Peeps,

Please forgive my crude drawing (below), but pix didn't give the detail.

The aftermarket antenna on my 79 has three wires entering it: yellow, white and brown. I need to know which wire does what.

I took out the antenna (an Audiovox) and opened it up to see what specifically the wires connect to. There is a plastic block with a circular copper disk in its center that rotates. There is a small cut-out in the copper at the edge of the disc. At the top of the block there are four spades. Three of the spades extend through the block and make contact with the copper disk. The fourth does not. There is a small capacitor (??) connecting two of the spades (#'s 1 and 3).

Of the spades that extend through the block,the ones on the outside (#'s 1 and 3) are shorter and mesh with the cut-out in the face of the copper disk. I'm guessing that once the antenna gets a trigger this disc will rotate and provide power to the motor until one of these spades encounters the cut-out and the circuit is broken. The center spade is longer and will always be able to contact copper on the face of the disc. It connects to the red wire of the drive motor.

The wires entering the antenna connect as follows:

Brown wire connect to the short spade on the left rear (#1)
White wire connects to the short spade on the right rear (#3)
Yellow wire connects to the spade on the right front (#4) taht does not extend through the block.

Another white wire also connects at spade 4 with the yellow wire. It connects to the antenna drive motor.

A red wire comes from the drive motor and connects to long spade #2, center rear.

The top drawing shows the block from the front; the detail at the bottom is how the wires connect if looking at the block from the top:



Here's a live shot:



I do not have the original relay and it is my understanding that aftermarket antennas using modern head units (ie Kenwood Excelon) don't need it. Therefore, what do I connect these wires to? One should be constant power, one ground and one the blue trigger from the HU. Thoughts?

Thanks to all,
Steve

 

Anyone?

 

Here's what I do the motor has red and White. I would hook it up to a three postion switch and use the switch to raise and lower the antenna. This way you can lower it in an strong area like downtown to weaken the signal so the FM sounds fine.

 

I really have no idea what the colors mean without a stock wiring digram and being able to test everything myself, but I can tell you that you won't need a relay like the factory used. The new head unit sends a signal to the antenna and amp both, to turn them on. The blue wire is the power antenna wire, and the blue with white is the amp wire. The antenna 'should' have 12V at all times and a constant ground and all it requires to extend is a 12V signal via either the relay or the remote wire. So long as it has that signal it extends and if the signal is cut, like if you turn off the head unit, the antenna retracts. You just need to find out which wire on your harness to the antenna has constant power, or at least on with the IGN, and then the ground. The last wire 'should' be the trigger wire that connects to the remote wire from the head unit.

You can test this by running a 12V wire from the battery and touching it to the suspect terminal while the IGN system is energized, and see if the antenna extends.

 

Best educated guess then...I'm thinking the yellow wire is the trigger and the brown white wires are interchangeable as the ground or constant hot. they are connected by virtue of the "cap" or whatever the gizmo is that is attached to the pair at the top of the block. The current gets broken when the wheel spins to the opening.

If I connect the brown to the pos and the white to the neg on my battery I should expect nothing to happen. If I then tap the yellow to the pos I would expect extension or retraction. Is this a safe way to test this?

Thanks to all, S

 

Probably not, because if it's wrong it could smoke the antenna. Problem is I can't think of a different way to 'test' without knowing more specifics about the antenna.

 

You could get it to work, but you would need a 4 pole (3 used) double throw relay.
You can test it by hooking up 12V between #2 and #4 wires to see which combination makes the antenna go up and which makes it store. Be careful not to let the center disk rotate past either cutout while testing, it won't stop on it's own. once you know which combination makes the antenna raise +/- and which makes it lower, and which way the disk rotates when the mast is raising and which way it goes when lowering, i can draw you a schem, if you would like.

 

yes please...that would be great!

Bottom line, if I can't get it to work I'll just raise it manually or replace it with a new aftermarket unit that has instructions on how to install.

 

Before I can draw one I'll need some information. Which polarity of 12V accross #2 and #4 causes the anrenna to rais and when it is raising which way the wheel spins, CCW or CW. that should be about it, like i said above, when testing with power from 2 to 4, don't let the wheel spin past either cut outs on #1 or #3, it won't stop by itself. C.

 

Here's a thread that will help. Take a careful look at the pic of the wiring diagram. Just this past weekend I installed a new one in my 79.

http://forums.corvetteforum.com/show...=power+antenna

 

Ok, here is your Scematic. It requires 2 double pole, double throw, 12V relays (2 relays with 2 switches each in them) that's all that's required.
On the two contacts marked Down and Up, one of them will go 1, the other to 3 .
If when the antenna is retracting, (Down), the disk is rotating the hole towards lead 1, then you hook up the 'Down' relay point to lead 1 and the other to 3
If when retracting (Down) the disk is rotating the hole towards lead 3, then you hook the 'Down' contact to lead 3 and the 'Up' to 1.
Or you can just buy a new Antenna that works on the single Blue wire which is what I'd recomend ,, but this will work. C.

(the 'Up & 'down' refered to are for the leads on the bottom of the drawing, NOT the referance up & down on the first upper set of contacts)

(this is ofcours assuming that the antenna retracts when lead 2 is at 12V and 4 is Grounded, if it works oppositly, Use the second Schematic)

 

Many thanks RM373! Let me ponder it all and get the relay(s) I need to get it going.

Enjoy, Steve

 

You know I almost went the route of an after market electric antenna, that didn't need any relays at all. Simple signal wire to extend and that was it.

Then, I took some advice I gave to a guy a few years ago at the audio shop...a windshield antenna.

It's fast and easy to install...wires hide behind the A-pillar trim, and it plugs right in and only needs a 12V source which can piggy back off of the 12V to the head unit.

I love mine, and I have it up in the top right corner of the inside of the windshield on the passenger side. It's hard to see unless you're looking for it, and it works great with all of the local radio stations.

The hole in back will have to be glassed or plugged, but to me it was a small price to pay.

http://www.crutchfield.com/App/Produ...na&i=12044UA20