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What if question for you antenna gurus.

Dutchman11

Member
Sep 9, 2013
25
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I have a an Imax 2000 up now and have acquired another and was thinking could I hook them up in series like a pair of firestick antennas. Is it possible to do this with the Imax 2000 and would there be any benefit. Sure would be cool.(y)
 

You can co-phase them but it requires a phasing harness of a specific length and OTTOMH using 75 Ohm coax up to the T piece. It will give you gain but it'll be directional.

If you feel really ambitious you can get four of them and create a four square array and use a switch box to enable you to use them like a beam. Distances, the ground radials, coax lengths etc are critical though.

It is however just easier to buy a beam.
 
The first question is what is your goals for using two antennas instead of one? If just because you can is the answer I think you would be setting yourself up for disappointment.

CB, Ham, it doesn't matter as the principles that make antennas work applies to both, as well as every other radio service in existance. Just remember, the power gets divided between the antennas so unless they are set up in such a way that there is a benefit in one or two directions at the expense of the others, the extra hassle essentially amounts to a loss in performance.

The so called "co-phasing" (I hate that term) is an option, but other phasing methods (such as an end fire array) can also give good gain with much narrower spacing between the antennas (or less overall space).


The DB
 
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This will be used for cb and not ham, if that makes a difference.


Makes no difference whatsoever. I am amazed at how many people think that antenna principles are different between CB and ham radio.

On second though since CB amps are vastly more efficient than ham amps I can see why some folks think that antennas are different. :whistle:
 
The reason for the two antennas is I have 2 of the same the second is I am on a fixed income and can't afford a set of beams and rotor and box as much as I would like to have them the other thing is getting them up I have had 2 heart surgeries and 5 heart attacks so me putting them up is just about out of the question but the Imax with a little help can go up. I am just getting back into radios and do not know allot about antenna design so I am just learning. Please put up with the learning curve. Thanks
 
There would be a benefit of you want/need to talk with some directionality. For me I might do what you are doing because I live outside of town. If I set them up properly, a little directionality would be good to hit all the locals in town.
 
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This will be used for cb and not ham, if that makes a difference.

No it doesn't. Radio is radio no matter what the application. What works for amateur radio works for CB and vice versa. The only differences are with what is legal to do in your country.
 
The reason for the two antennas is I have 2 of the same the second is I am on a fixed income and can't afford a set of beams and rotor and box as much as I would like to have them the other thing is getting them up I have had 2 heart surgeries and 5 heart attacks so me putting them up is just about out of the question but the Imax with a little help can go up. I am just getting back into radios and do not know allot about antenna design so I am just learning. Please put up with the learning curve. Thanks

A Moxon beam is something that can be built for a lot less than the cost of an Imax antenna and a Moxon kit bought for about the same price. If you can nail bits of wood in a letter H and string wire round the outside of it you can build a Moxon.

Put it up on even a 20ft pole with a cheap TV rotator and it'll leave the Imax in the dust for DX work.

KD6WD'S Moxon Antenna Project
 
hmmm

Phased array using the christman method of forced current phasing.

Couple of relays and switches and have a bi directional end fire array or co phased.

Made one for 40 meters worked great for DX.
 
36 feet being a full wavelength is a bit to far apart if you are looking for maximum gain in two directions, but will still work fine. The wider lobes in such a setup are actually inline with the antennas, and not broadside to them. If you are looking for peak gain broadside to the antennas 5/8 wavelength apart should be your goal. This will net nearly twice the total gain as the antennas being a full wavelength apart at the cost of the width of the patterns.


The DB
 
The only benefit to using a 'phased array' (more than one antenna) is that the radiation pattern becomes directional. Depending on how that 'phasing/timing' is done, that radiation pattern can be switched 90 degrees. That's -bi-directional' not just in one direction, should'a said that to start with. That's the 'simple' way of doing it, there's also a more complicated way of doing that phasing where the radiation pattern is in a single rather than a bi-directional thingy. There's also a method of 'steering' that directional pattern, but that really get's complicated.
The 'simpler' way of doing that phasing is by using the feed lines to both antennas. It means doubling the amount of feed line, usually, and then switching between two lengths going to one of those antennas. (That's documented in more than one place, so just 'google' it.) There are requirements in antenna spacing too. Just depends on how much effort you wanna go to.
Have fun.
- 'Doc

That directional pattern never get's really 'sharp', it's more a flood-light thingy than a 'spot-light' thingy.
 

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