DIY: Internal home made car antenna

Discussion in 'DIY Guides' started by CharlieVoodoo, Jan 9, 2011.

  1. CharlieVoodoo

    CharlieVoodoo New Member

    Joined:
    Apr 16, 2010
    Messages:
    23
    Location:
    Montijo, Portugal
    This is how I installed an internal car antenna in my EK4 connected to the rear window defogger

    [​IMG]

    PARTS NEEDED:

    » 4meters (aprox.) 50Ω Coaxial cable
    » 1 Female terminal
    » 1 Fork terminal
    » 1 Male antenna plug
    » 1 Capacitor

    [​IMG]

    [​IMG]

    [​IMG]

    [​IMG]

    [​IMG]

    *The fork terminal that will be attached to a chassis screw (ground=negative) has to be open because it has to be spiked to the external layer of the coaxial cable later.

    Example:
    [​IMG]

    Defogger connection scheme:

    [​IMG]

    Explanation:

    A) Weld the internal layer of the coaxial cable to one end of the capacitor.

    B) Spike and weld the other end of the capacitor to the female terminal. This terminal will be connected to the positive pole in the rear window defogger. (in my car that is left hand drive, the positive pole of the rear window defogger is in the drivers side)

    C) Strip ONLY the outside rubber of the coaxial cable so that only the outer conductive layer is visible to spike the fork terminal that will be connected to a chassis screw.
    Before stripping the rubber, measure the distance needed to get to the chassis screw that you choose to hold this terminal

    *In the other end of the coaxial cable, install the male antenna plug that I don't think that will be needed to explain how to do.



    PROCEDURE IN MY CAR:

    In this first step after finding out that this was the positive pole, was used an antenna frequency analyzer/tuner just to make sure that there will be a good signal capture.
    (Don't really need to have or use this device, is guaranteed that this kind of antenna is aproved and works fine)

    [​IMG]

    [​IMG]

    [​IMG]

    This is the coaxial cable that was used.

    [​IMG]

    The capacitor was used to eliminate the return of electrical charge to the radio when the defogger is turned on. (821k/3kV Capacitor)
    [​IMG]

    This is the coaxial cable ready to install in the car with the antenna plug in one end and the capacitor and female terminal in the other end to connect to the rear window defogger.

    [​IMG]

    This step is when the outside rubber of the cable was stripped to spike the fork terminal and hold it in a chassis screw behind the rear seats.

    [​IMG]

    [​IMG]

    This is the final result. Very discrete and fully functional!
    [​IMG]

    I'm sorry if there are some writing errors... I'm portuguese. :p
     
  2. BabyTypeR

    BabyTypeR Normz Photography

    Joined:
    Oct 5, 2007
    Messages:
    75
    Location:
    New York
    Nice write up dude!! and very creative!
     
  3. robbieD

    robbieD Daily Driven EK9 Donator

    Joined:
    Sep 19, 2010
    Messages:
    1,079
    Location:
    Hampshire, UK
    Excellent write up!

    What is the reception like? Any good?
     
  4. jordan101

    jordan101 New Member

    Joined:
    Feb 25, 2010
    Messages:
    6,046
    Media:
    15
    Albums:
    3
    Location:
    GLASGOW
    thats pretty clever :) as said whats the reception like?does it come and go?
     
  5. CharlieVoodoo

    CharlieVoodoo New Member

    Joined:
    Apr 16, 2010
    Messages:
    23
    Location:
    Montijo, Portugal
    The FM reception is great!!! Even when the deffoger is turned on, there are no problems.
    It was used my brother-in-law's frequency analyser as you see in the pictures to make sure of that. One of his hobbies is amateur radio (I don't know if you say it like this) so he really understands all of that stuff.

    Only the AM reception gets a little bit of noise when the defogger is on. I don't have problems with that because here in Portugal nobody listens to AM broadcasting. Maybe in other areas this won't be a problem...

    I hear in some internet forums that the internal antennas that some people put in the windscreens are not very good in reception... personally I never used one so I don't know for sure.
     
  6. cormy

    cormy B18c ek9.... Donator

    Joined:
    Mar 27, 2007
    Messages:
    675
    Location:
    Dublin
    Good idea. What's the capacitor used in Farads?
     
  7. robbieD

    robbieD Daily Driven EK9 Donator

    Joined:
    Sep 19, 2010
    Messages:
    1,079
    Location:
    Hampshire, UK
    Your english is very good, so don't worry about that. :nice:

    Glad the reception is good.

    I was thinking about removing the arial and thought I would have to pay for an internal one but not anymore!

    Did you run the Coaxial cable along the floor or along the roof?

    Thanks again for the write up :))
     
  8. mawticulous

    mawticulous Narf!

    Joined:
    Jan 10, 2011
    Messages:
    122
    Media:
    7
    Albums:
    2
    Location:
    So Cal
    that is a great idea, is there any way to repair the defogger. mine never worked and after i peeled all the tint off the back window i came to find out all the stuff going across the copper lines was missing.
     
  9. s-tuned

    s-tuned custom roll cages

    Joined:
    Jan 3, 2011
    Messages:
    122
    Location:
    LOS ANGELES CA
    this is a great idea good write up
     
  10. xristos

    xristos New Member

    Joined:
    Mar 13, 2010
    Messages:
    233
    Location:
    greece
    Great idea and excellent write up!
    Congrats mate!
     
  11. CharlieVoodoo

    CharlieVoodoo New Member

    Joined:
    Apr 16, 2010
    Messages:
    23
    Location:
    Montijo, Portugal
    Cormy, I don't know the value of the capacitor in farads... I don't have great knowlege about that particular matter to be honest.

    If it helps, a friend of mine in another internet forum asked if he could use for example a 270pF/2000v capacitor instead a high voltage one because he couldn't find one like the one I used.
    I asked this to my brother-in-law because he's the real electronic's brain guy and he said that a capacitor like this also does the job.
    Hope this information is helpful to you.

    robbieD, I ran the cable along the floor.

    mawticulous, sorry but I don't know how to help you with your problem.
     
  12. CharlieVoodoo

    CharlieVoodoo New Member

    Joined:
    Apr 16, 2010
    Messages:
    23
    Location:
    Montijo, Portugal
    I've got some news about the capacitors that can be used. After asking my brother-in-law, he told me that the ideal capacitors that can be used are between approximately 470 and 1000pF.
     
  13. lonemeno

    lonemeno New Member

    Joined:
    Sep 3, 2013
    Messages:
    5
    not to jack or any thing this is done on a 4 door to do it on a hatchback/coupe i made a Y harness that plugs in to the defroster male end of the harness before the tail lights on the left hand side of the car on the driver side (LHD) and grounded it to the brace then took a Honda accord antenna wire and hooked it up in the above post thanks for the info now i can delete the antenna
     
  14. evalex

    evalex New Member

    Joined:
    Jun 17, 2014
    Messages:
    11
    Awesome idea, can't believe noone has ever thought of this before! Will definitely be doing this! :thanks:
     
  15. ALEX-CY

    ALEX-CY Member

    Joined:
    Mar 17, 2009
    Messages:
    481
    very clever
    :thanks:
     

Share This Page