Making a modern power antenna work in an S30

[Jehannum]

I adapted a Metra PW-22 today to work on my 240Z with the antenna switch.

Turns out, all I had to do was to put a diode between the red and blue wires, and then hook them up to the switch's outputs.

For lowering the antenna, the diode allows you to power the mast motor without energizing the magnet (and switching the relay).

For raising the antenna, the diode allows you to power the mast motor and energize the magnet (thus switching the relay).

The PW-22 can be had for $65 at Autozone, about $100 cheaper than the MSA replacement.

[280~Master]

There should be a blue wire from any new stereo to the hot wire on the antenna and to an amp for those hard of hearing. then a ground wire.

Why did you use a diode??

[Jehannum]

There should be a blue wire from any new stereo to the hot wire on the antenna and to an amp for those hard of hearing. then a ground wire.

Why did you use a diode??

Because I'm keeping the original AM radio, and the raise/lower switch.

The diode is just a one-way gate, so that I can feed both the switching mechanism in the relay and the motor in the antenna mast with the "up" lead, and just the motor in the antenna mast with the "down" lead from the switch.

Edited March 15, 2009 by Jehannum

[280~Master]

I understand the Stock AM radio with a diode,

but now that paul harvey is gone who do you listen to?

[Jehannum]

I usually stick with "Real Oldies 1600" when I'm tired of right-wing hate speech.

I really just don't see the need to put a fancy stereo in, and I was getting a little irritated with my old broken antenna. It was OEM, but the motor was toast, and the mast was stuck halfway down. Made it a little hard to put my car cover on, or get it washed.

[280~Master]

I hate all those left and right wing sided speechers. Unless it about me or the Z to heck with it.

[240 in OZ]

Any chance of posting a pic and details of the diode used?

Thanks

[Jehannum]

:classic:I've already buttoned up the car, so pictures are unlikely until next weekend (when I tear it all apart again to sand and paint the area around the antenna hole).

The diode was the same one I used in my 280ZX alternator conversion - You should be able to pick one or several up from somewhere like digikey using the part number 1N5402.

The idea is to put the diode between the two lines stock in the car (blue/red stripe for up, blue/white stripe for down) with the diode's anode towards the "up" lead. Then connect the "antenna signal" lead on the antenna to the "up" lead, and the "constant power" lead on the antenna to the "down" lead.

Doing so will allow you to do the whole shebang with the switch - raise and lower in increments of your desire, in the order that you desire (though the antenna retains the intelligence to stop lowering at the bottom, and stop raising at the top).

The diagram I've attached should help somewhat (though I'm somewhat rusty on my electrical diagramming skills):

Edited March 16, 2009 by Jehannum

[Jehannum]

The net result of that is 1) when you press "up", both the red and blue wires to the antenna receive around 12V, and 2) when you press "down", only the red wire receives 12V.

That works, because the antenna has a DPDT relay on it. When both the trigger and the source receive voltage, the relay switches, and the leads feeding the motor in the mast get "reversed". When just the source receives voltage, the leads feeding the motor don't get reversed. There's a little gear driven thing inside the mast that controls the logic for how long to allow the mast to run up and down.

Edited March 16, 2009 by Jehannum

[TomoHawk]

I can see that this kind of wiring works, but you can only have it fully up or down. What if you just want to have the antenna only 1/2 way up, when you drive in the city?

thxZ

[Arne]

I can see that this kind of wiring works, but you can only have it fully up or down. What if you just want to have the antenna only 1/2 way up, when you drive in the city?

thxZ

I don't think that's possible with this type of antenna.

[TomoHawk]

It is, but you'll need to use some non-factory parts, like for the up/down switch.