Under dash antenna switch

[BertD]

Hello all.  I just picked up a 250SL years after having another 250.  The previous owner had an intermittent switch (up and down) installed to raise and lower the antenna (Hirschmann).  I would like to connect the antenna to the modern radio antenna line. 

On the current setup, there is a 12V line tied into the antenna switch from the 12V line going to the clock.  One line from the antenna goes to the up terminal, the other line from the antenna goes to the down terminal.

On the radio, there is a single line that when powered causes the antenna to raise.  When power is lost, the antenna comes down. 

I can't seem to wrap my mind around how I would wire this.  I would think I would need some intermediate relay telling the antenna which way to go?

Thanks in advance for any guidance.

Bert

[rwmastel]

BertD,

There are a couple original radio installation manuals here, do they help?
https://www.sl113.org/wiki/Electrical/RadioAndAntenna

[Pawel66]

Most of the antennas I came across have two "+" lines:
- one is the permanent power; you can connect it to the car either before or after ignition, but if you do it after ignition, antenna will not operate after ignition is off, so best it to connect it to permanent power (this is how it is originally)
- the other is a signal wire from a radio or from switch; when power appears on this wire, antenna goes up and stays, when power is cut off antenna goes down; the switch imitates the radio

The wires coming to your switch are, I think, not "up" and "down" wires, but they are "+" that is either sent to antenna by the switch (closed, up position in the switch, antenna goes up and stays up) or cut off (open, "down" position of the switch, antenna goes down).

It is shown here: https://www.sl113.org/wiki/Electrical/Antenna?action=download&upname=AUTA2040instruction.pdf

ws (weiss or white) with a switch pictogram is the signal wire. rt (rot or red) is the permanent power.

If you connect power wire to permanent power and signal wire to power after ignition, through switch to the antenna, antenna will behave in the following way:
- with switch on/closed/up it will extend when you turn ignition on and will go down when you turn ignition off
- when the car is running and you put switch into off/open/down position, antenna will go down; press it up, it will go up
- with switch off/open/down nothing will happen until you switch it on

All power connections need to be fused. In W113 you probably have the permanent power from harness, all is needed is to connect signal wire to switch and switch to power after ignition, e.g. to one of the fuses that are powered after ignition (then it is a fused connection if you do it on receiver side of the fuses).

[BertD]

Thanks for the reply.  I've looked through all the technical documents on the site, and I haven't been able to figure it out yet.

[BertD]

Most of the antennas I came across have two "+" lines:
- one is the permanent power; you can connect it to the car either before or after ignition, but if you do it after ignition, antenna will not operate after ignition is off, so best it to connect it to permanent power (this is how it is originally)
- the other is a signal wire from a radio or from switch; when power appears on this wire, antenna goes up and stays, when power is cut off antenna goes down; the switch imitates the radio

The wires coming to your switch are, I think, not "up" and "down" wires, but they are "+" that is either sent to antenna by the switch (closed, up position in the switch, antenna goes up and stays up) or cut off (open, "down" position of the switch, antenna goes down).

It is shown here: https://www.sl113.org/wiki/Electrical/Antenna?action=download&upname=AUTA2040instruction.pdf

ws (weiss or white) with a switch pictogram is the signal wire. rt (rot or red) is the permanent power.

If you connect power wire to permanent power and signal wire to power after ignition, through switch to the antenna, antenna will behave in the following way:
- with switch on/closed/up it will extend when you turn ignition on and will go down when you turn ignition off
- when the car is running and you put switch into off/open/down position, antenna will go down; press it up, it will go up
- with switch off/open/down nothing will happen until you switch it on

All power connections need to be fused. In W113 you probably have the permanent power from harness, all is needed is to connect signal wire to switch and switch to power after ignition, e.g. to one of the fuses that are powered after ignition (then it is a fused connection if you do it on receiver side of the fuses).

I am trying to think through this.  My thought is this intermittent switch is closing on the up and on the down just in different directions.  Its open when the switch is released and comes back to center.  The way you describe it makes much more sense. 

Another interesting thing about the setup on my car is that there doesn't seem to be any limit switch or timer.  If I hold the switch up, the motor only stops when I release the switch.  The same things happens bringing it down.  I would think there would need to be some limits set.

I'm going to video my situation, and maybe that will help describe it better.

Thanks for your willingness to help.

Bert

[Pawel66]

In the regular antenna type I described the limits are internal to the antenna.

You probably have a different type of antenna that needs to be wired differently... What type of antenna do you have?

[BertD]

In the regular antenna type I described the limits are internal to the antenna.

You probably have a different type of antenna that needs to be wired differently... What type of antenna do you have?

Its a Hirschmann, but I haven't been able to get a clear enough look to see the model#.  Doing that over the weekend.

Thanks,
Bert

[Pawel66]

Check out this thread: https://www.sl113.org/forums/index.php?topic=30566.0

Some antennas require separate relay that takes care of the movements and liniters.

May want to look also here: https://www.sl113.org/forums/index.php?topic=30723.0

[specracer]

My car when I got it also had a 3 position switch for the antenna (up, down, and off). 12v to one wire for up, then 12v to the other wire for down. Not easily compatible with the maintained 12v trigger output of the Becker radio.

I replaced the antenna with one set up to go up, with a maintained 12v trigger voltage, then it goes down when the control 12v goes away, when the radio turns off (obviously there is a 12v constant power source as well, to drive the motor). I found this antenna through this site.