Dual antennas or single?

Yep just turn off your head lights and look for a red car with a strange glow to the driver.

 

Actually, I wasa thinkin' that may be how the housefly finds all those illegals to report! If they glow,they gotta go! LOL

Wonder if he's from Arizona? hehe

 

So on duel set up's where is the splitter? i need to track down a high standing wave on my '01 INT. want to check all connections..

 

Other: (please explain)

dual top loaded antennas from 4' up to and including the maximum length that will still allow clearance of standard 13'6" or whatever the lowest clearance is that you have to navigate.

properly installed and matched, dual top loaded antennas will deliver more signal in and out to the front and rear of tractors whether they're pulling tanks, flatbeds, boxes or ramps and in addition, tractors that are equipped with dual stacks will perform the best as the stacks themselves become part of the antenna system, like it or not. on the flip side of that coin, if you're using dual antennas with a single stack the symmetry of the pattern will be distorted, as in "not uniform".

most of the problems encountered in attempting to get dual antenna systems to perform properly include:

wrong radio guide (RG) feedline
lengths that do not yield proper phasing
antennas in close proximity to stacks
insufficient height of electrical loading
antennas are unable to "see" each other
the antennas are not identical

combinations of two or more of these common mistakes can be so overwhelming that many immediately draw the conclusion that a single antenna is the way to go. being aware of these shortcomings, understanding and dealing with them in an orderly fashion by eliminating them one at a time can yield an antenna system unequalled in performance by the majority of installations on the road today.

in addition to all of the above there is also a lot of incorrect and erroneous information with regard to this topic all over the internet.
here's an example:

http://www.cartaste.com/transport-equipment/article-2-02141.html

here's one of the myths that i hear stated most often, the author of the article linked to above also repeats the same thing.

"Another problem with 2 antennas is you start out with 1/2 the power at each antenna."

and most people make this statement like it's a problem or a shortcoming of some sort. it's not. if the phasing harness is constructed of the proper radio guide (RG) type and the two lines are of the proper length then half the job is done, the job of seeing to it that the signals from the two antennas arrive in the proper "timing" so that the principle of constructive interference can be fully taken advantage of.

definition: constructive interference, the interference of two or more waves of equal frequency and phase, resulting in their mutual reinforcement and producing a single amplitude equal to the sum of the amplitudes of the individual waves.

so it matters not that the power is divided up between the antennas because under the above stated conditions they recombine in mutual reinforcement of one another and produce a single amplitude equal to the sum of the amplitudes of the individual signals or waves generated by the individual antennas.

the pattern produced under these conditions is at right angles to the plane of the antennas, which is to the front and rear of the tractor. signal transmission and reception is reduced in directions parallel to the plane of the array and enhanced at right angles to the plane of the array, providing the directional effect. contrary to popular opinion this effect is in full force at antenna spacings from one-eighth to one-quarter wavelength.

it's when the incorrect radio guide (RG) feedline is used and the lengths are not those that are required to establish the proper phasing creating the effect defined by the definition of the term above that dual antennas don't function in the manner in which they were designed.

 

" "Another problem with 2 antennas is you start out with 1/2 the power at each antenna."

TRUE you do get this however it is not all bad if you stack any antenna power is devided between them however you can get gain +3db if you can add them back together corectly.

And yes you can run as many antennas as you want gaining some amount of " DB" gain less losses each time you double the number of antennas ....

Here is a example of going too far ....

http://www.w5un.net/EME%20Array.JPG

 

I love the rotor system on the w5un array.

Leon
(kc0iv)

 

Yep nothing like your own train track .....

 

JOLSEN,

Hey what is your feed back about Werner? I am at AIT and have the option of Werner or Night Reefer and wanted to see if you could shed some feed back.

 

Yep at 28 Mhz very true .......

 

I have gone through the single antenna and the dual antenna deal on both the trucks I have run. both trucks had better radio reception and range using cophased (dual) over a single antenna.

I had a huge loss of to the opposite rear side of were the single antenna was located.