| Author |
Message |
    
Kid_vicious
Senior Member
Username: Kid_vicious
Post Number: 2443
Registered: 9-2004
| | Posted on Saturday, March 03, 2007 - 10:30 pm: | 
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bought an old CB projects book from 1968 and in it they describe how to make your mobile into a vertical beam antenna with four antennas placed front to back on the vehicle in specified lengths from eachother.
the book claims 15db forward gain, which seems a bit high, but who knows.
anyone ever seen or tried this?
if it works i may do it to my old pickup truck.
will post the details of it when i have more time.
matt |
Captian_radio
Intermediate Member
Username: Captian_radio
Post Number: 152
Registered: 9-2004
| | Posted on Sunday, March 04, 2007 - 8:37 am: |
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Kid , sounds like it might make a great phased array, would be nice to be able to switch the various antennas to make it very directional.In (therory) can't spell to early in the am, sounds like it might work ok.I would like to see more info or pics of this setup.
Bob CEF451 |
Tech237
Moderator
Username: Tech237
Post Number: 715
Registered: 4-2004
| | Posted on Sunday, March 04, 2007 - 9:13 am: |
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I have seen it done back in the 70s. Worked OK but can be a bit cumbersome trying to rotate the beam..If you have the antennas and time give it a go.
Simon
Tech237
KD7IEB
|
Dale
Advanced Member
Username: Dale
Post Number: 652
Registered: 12-2002
| | Posted on Sunday, March 04, 2007 - 10:02 am: |
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ive seen inm keydowns were people would have
a surban with 3 preator10k hard mounted inline.
one in center of roof one towards the front and the other towards the rear is this what ya mean? |
Wildrat
Senior Member
Username: Wildrat
Post Number: 1264
Registered: 12-2003
| | Posted on Sunday, March 04, 2007 - 7:13 pm: |
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Like Dale said, you see them at Key-downs in all varieties hooked to big ole DM's.
WILDRAT
MARK
27.285MHZ
CEF674
CVC029
|
Patzerozero
Senior Member
Username: Patzerozero
Post Number: 3531
Registered: 7-2004
| | Posted on Sunday, March 04, 2007 - 8:22 pm: |
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15db....NOT. very directional? definitely. depending on the vehicle's roof length, whether you use reflector, director or both, etc. build it just like a beam. tune a driven element, then decide what the other element(s) are, & space them appropriately, after shortening(or lengthening), etc. remember, you are using 1/4 wavelength for the driven element, not 1/2 wave, don't expect full-sized beam results-dramatic though they will be. sometimes a hassle, but it will work.  |
Kid_vicious
Senior Member
Username: Kid_vicious
Post Number: 2444
Registered: 9-2004
| | Posted on Sunday, March 04, 2007 - 11:17 pm: |
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im glad others are ready to think outside the box a bit with me.LOL
the picture of the vehicle in the book is a VW bug!
picture the car facing to the left so you are looking at the drivers side.
the antenna mounted to the rear bumper is a 102" whip with the center conductor grounded.
it is the reflector.
the second one is a base loaded CB whip like a wilson 1000, mounted up high near the rear door pillar.
it is connected via coax to the radio.
it is the driven element.
then there is a "shortened 10 meter whip" mounted in front of the drivers window. i take this to be another base loaded whip, but could be wrong.
this is also center pin grounded and is the first director.
then, another 102" whip is mounted on the front bumper, also center pin grounded and is the second director element.
all antennas must be in line with eachother with respect to the side of the car they are mounted on, and will be obviously highly directional to the front of the car.
dont have the spacings between elements from front to back, but i will bring the book tomorrow and post them.
when i get my f250 on the road again, i will really want to try this.
nice to have a vehicle you dont mind welding to and drilling holes in!
who else has seen this done?
matt |
Twixer
New member
Username: Twixer
Post Number: 2
Registered: 3-2007
| | Posted on Sunday, March 18, 2007 - 3:37 pm: |
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Hey Kid Vicous... Was that VW from Canada?..I used to talk to a guy over there and you would think he was on a base. He would point the Bug in your direction and really talk. |
Chrisbama351
Junior Member
Username: Chrisbama351
Post Number: 13
Registered: 2-2018
| | Posted on Sunday, November 27, 2022 - 5:00 am: |
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Kid Vicous that could be two driven antennas in the middle a director on the front and reflector on the rear? What is the book? Or Could you post pics or more details? I would like to see their design. Thanks, ala"Bama" 351 in Colorado |
