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#86071 - 08/04/2002 17:43 Antenna retract problem
wfaulk
carpal tunnel

Registered: 25/12/2000
Posts: 16706
Loc: Raleigh, NC US
I just got my antenna signal wired properly (lazy) and I have a problem where the antenna does not retract when the radio is shut off. The FAQ says:
    Hugo discovered that some power antenna relays have a current draw problem and the voltage on the power antenna wire doesn't fall enough to make the antenna go down. If this is happening to you, try attaching a 1k resistor between the power antenna wire and ground and see if it solves the problem.
but that's not clear to me. I'm sure that it's enough information on its own, but I'm not entirely sure what to do with that information. Does it mean that I should attach a resistor to join the wire coming out of my tuner harness to the wire going to the antenna (I think not) or between where those two wires join and a ground, or does this all need to be done back at the antenna or what? (And I assume that should be a 1kOhm resistor.)
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Bitt Faulk

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#86072 - 09/04/2002 01:26 Re: Antenna retract problem [Re: wfaulk]
mtempsch
pooh-bah

Registered: 02/06/2000
Posts: 1996
Loc: Gothenburg, Sweden
The problem, as it's been reported, is that the "control input" of the antenna
(I assume you have a separate +12V feed and ground (or grounded to chassis) to
it?) is very high impedance. As the empeg essentially disconnects its end of the
wire on "turn-off", the "charge" on the control input doesn't "bleed away" to ground.
The resistor offers a path to "bleed out" through (aka pull-down)

You can apply the 1kOhm resistor just about anywhere as long as the resistor
goes between the signal line and ground, for instance at the plug that connects to
the tuner module. It could also be applied internally, inside the module.

IMO, since this fix is more or less antenna specific, I'd look at placing the resistor by the antenna.

HTH,

/Michael

Edit: A little ascii art to assist


Tuner -blue------------------*---------------------------*-----------Antenna-- +12V
module | |
|_resistor_______*____Ground



The blue cable comes out of the tuner module plug, is crimped or soldered to the wire that controls
the antenna. The resistor goes between this line (anywhere, but I'd do it by the antenna,
if at all accessible) and ground (anywhere).
* denotes connections.


Edited by mtempsch (09/04/2002 01:35)
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/Michael

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#86073 - 09/04/2002 10:41 Re: Antenna retract problem [Re: mtempsch]
tfabris
carpal tunnel

Registered: 20/12/1999
Posts: 31600
Loc: Seattle, WA
Your illustration shows an extra line between ground and antenna. Sure you wanted it to look that way?
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Tony Fabris

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#86074 - 09/04/2002 13:56 Re: Antenna retract problem [Re: tfabris]
mtempsch
pooh-bah

Registered: 02/06/2000
Posts: 1996
Loc: Gothenburg, Sweden
Yes, in case it isn't grounded by the antenna/motor housing directly (ie you have 3 wires to the antenna/motor assembly; +12, Ground and remote control). Consider it optional.

/Michael
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/Michael

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#86075 - 09/04/2002 14:07 Re: Antenna retract problem [Re: tfabris]
wfaulk
carpal tunnel

Registered: 25/12/2000
Posts: 16706
Loc: Raleigh, NC US
I believe so. I got a resistor wired up and it works now. Basically, there needs to be a resistor wired in parallel with the antenna in reference to the signal (not power) and ground. I decided to do it on the dashboard side because I already had the dash pulled apart. But it shouldn't really make any difference. Here's what I did (ignoring the power to the antenna):
Tuner--(blue)---+---------(antenna)

| |
| |
resistor (ant. ground)-\
| \
| > (ostensibly, these are connected somewhere)
| /
empeg--(black)--+--------(dash ground)-/
Which should sum up to:
Tuner--(blue)---+-----------+

| |
resistor antenna
| |
empeg--(black)--+-----+-----+
|
(ground)
The FAQ could be a little clearer on this.
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Bitt Faulk

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#86076 - 09/04/2002 14:48 Re: Antenna retract problem [Re: wfaulk]
tfabris
carpal tunnel

Registered: 20/12/1999
Posts: 31600
Loc: Seattle, WA
I don't see how "1k resistor between the power antenna wire and ground" could be any less clear.

Tell me how that could be interpreted to mean anything other than the thing illustrated above.
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Tony Fabris

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#86077 - 09/04/2002 14:58 Re: Antenna retract problem [Re: tfabris]
wfaulk
carpal tunnel

Registered: 25/12/2000
Posts: 16706
Loc: Raleigh, NC US
I don't really know. I guess the fact that I'm not that comfortable with this sort of stuff just makes me nervous. Maybe a diagram?
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Bitt Faulk

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#86078 - 09/04/2002 15:42 Re: Antenna retract problem [Re: wfaulk]
tfabris
carpal tunnel

Registered: 20/12/1999
Posts: 31600
Loc: Seattle, WA
Sigh. OK...
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Tony Fabris

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#86079 - 09/04/2002 18:37 Re: Antenna retract problem [Re: tfabris]
wfaulk
carpal tunnel

Registered: 25/12/2000
Posts: 16706
Loc: Raleigh, NC US
Ooh! Now I remember why I was uncertain.

I didn't know if the wire leading to the antenna was a signal or ground wire (though I assumed it was a signal, if it were a ground wire, the description could be interpreted to mean placing the resistor inline), and I didn't know if the rest of the connections were to remain the same, only adding the resistor, or if I was supposed to rewire it so that the antenna wire was connected to the ground by way of the resistor, dropping some other connections.

I know those sound like asinine possibilities, and my assumption was what ended up being correct, but I don't know much about power electronics, and we are talking about connecting power and ground together (I know -- with a big ass resistor in between) on an out-of-warranty machine I have very little way of replacing.

The diagram certainly makes it clear.
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Bitt Faulk

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