M103C and Imax 2000

[CommsGuy]

I currently have an Imax 2000 up that I use for 10 and 11 meters that is working well. I also have a M103C on the way. I was pretty set on mounting the M103C vertically to use for local communications on 11 meters, but now am second guessing that. I guess I'm curious what kind of increase in local range I should expect with the M103C if I mount it vertically? If it will really help for local range I am not opposed to mounting it that way. I have also thought about mounting the M103C horizontally which is more the norm on 10 meters, then mounting the Imax above that. In that scenario I would also gain about 15 ft in height above where the Imax is currently located. Any thoughts?

 

[sp5it]

Directional antenna will outperform omni, especially deaf crap like Imax.
Mike

 

[Marconi]

CommsGuy welcome to the Forum and good luck. Be sure and keep us posted on your planned progress, OK?

I tend to agree with sp5it, the Imax is likely noisier than the horizontal M103C. But, from what I understand...there are ways to mitigate this noise using effective installation techniques.

If you want to set the beam vertical...then I would separate both antennas to 2 mounts separated close to a full wavelength and more.

Here are some links to WWDX searches on installing the Imax to help eliminate feed line noise. Just be careful, use common sense, and always test any recommendations you find interesting.

You will find me adding my 2 cents in these threads, but sometimes I might play devils advocate trying to get folks to tell us how they support their claims. I'm the curious type........

https://www.worldwidedx.com/search/81615637/?q=Imax+and+noise+on+the+feed+line.&o=date&c[node]=79

https://www.worldwidedx.com/search/81615662/?q=Imax+and+a+good+Common+Mode+choke&o=date&c[node]=79

https://www.worldwidedx.com/search/81615713/?q=Imax+with+a+capacitor+in+the+middle+section.&o=date

 

[Big Kahuna]

Vertically you’ll see gain over the imax but keep in mind you’ll need to point it in the right direction to whomever you’re talking to. Are the other local stations on beams or Omni antennas? Two beams pointing away from each other may do worse for local talking than two omnis for example.

Did you buy a rotor?

Also depends on what you consider local I have a buddy 35 miles south of me over some rough terrain, if we both go horizontal and point at each other we’ll have less noice and better chance then talking vertical.

 

[CommsGuy]

Vertically you’ll see gain over the imax but keep in mind you’ll need to point it in the right direction to whomever you’re talking to. Are the other local stations on beams or Omni antennas? Two beams pointing away from each other may do worse for local talking than two omnis for example.

Did you buy a rotor?

Also depends on what you consider local I have a buddy 35 miles south of me over some rough terrain, if we both go horizontal and point at each other we’ll have less noice and better chance then talking vertical.

I do have a tower and rotor up already. I guess I'm just curious if a 3 element beam is going to be a noticeable difference for me over the Imax if mounted vertically, or if getting the Imax up 15 feet higher would be just as good. The local stations are all mounted vertically. If there isn't going to be a big difference between the two I will just mount the beam horizontally and use it for dx.

 

[Big Kahuna]

I do have a tower and rotor up already. I guess I'm just curious if a 3 element beam is going to be a noticeable difference for me over the Imax if mounted vertically, or if getting the Imax up 15 feet higher would be just as good. The local stations are all mounted vertically. If there isn't going to be a big difference between the two I will just mount the beam horizontally and use it for dx.

If you can easily hear and talk to everyone locally on the omni now - putting it up 15 feet could make a difference.

I guess in my mind using a 3 element vertical for local talking with a rotor seems like overkill if you can already talk to everyone with the Omni. I'd much rather use it horizontal for DX.

 

[Marconi]

I'd much rather use it horizontal for DX.

BK makes really good sense.

 

[CommsGuy]

If you can easily hear and talk to everyone locally on the omni now - putting it up 15 feet could make a difference.

I guess in my mind using a 3 element vertical for local talking with a rotor seems like overkill if you can already talk to everyone with the Omni. I'd much rather use it horizontal for DX.

Well, that's the thing, I would like to get some more range locally. The Imax doesn't do bad, but I know there are some stations that are just a little too far out for the Imax that the M103C could help with.

Let me ask it this way. The base of my Imax is currently at about 25 feet on a roof tripod. I would mount the M103C on the tower which would put the boom at about 45-50 feet. Would I see a noticeable increase in range with the M103C mounted vertically at that height? Or should I just mount the M103C horizontal and put the Imax above that and continue to use the Imax for local stuff. I understand that if I mount the beam horizontal I will be for the most part limiting my local talk to other horizontal stations. I am a ham as well, so mounting horizontal is fine with me since I plan to use this on 10 meters as well.

 

[Big Kahuna]

So if you already have a tower why is the Imax 2000 not mounted on the very top? It would put the base at 45 ft vs 25ft? That might be enough to talk to those other local stations. Do you already have a multiband omni on top of the tower or something?

Before mounting the 103 vertically I'd try moving the Imax to the top of the tower as that's a lot less work. With the cycle on the upswing I'm looking forward to more DX so that's why I'd think horizontal is the way to go. But if your main goal is a stronger signal locally you could go vertical.

 

[CommsGuy]

So if you already have a tower why is the Imax 2000 not mounted on the very top? It would put the base at 45 ft vs 25ft? That might be enough to talk to those other local stations. Do you already have a multiband omni on top of the tower or something?

Before mounting the 103 vertically I'd try moving the Imax to the top of the tower as that's a lot less work. With the cycle on the upswing I'm looking forward to more DX so that's why I'd think horizontal is the way to go. But if your main goal is a stronger signal locally you could go vertical.

Yeah, currently I have a 2 meter vertical and 2 meter beam at the top of the tower. I will most likely be putting up another tower when it warms up some. I may swap the verticals around and see what happens.

 

[SIX-SHOOTER]

A Vertically mounted Beam will work far better than any omni directional ground plane. Also a vertical beam works great for local & DX but if you mount it horizontally you will kill your local & mobile station signals because of the approximately 20db of attenuation between the two polarities.

SIX-SHOOTER

 

[Big Kahuna]

Yeah if you're horizontal and someone is vertical locally the polarization really will be noticeable. My closest CB neighbor is 35 miles south and we did some tests and with me on a vertical and him on the horizontal he could barely hear me at the static level. He switched to the vertical and all of a sudden we're 2-3 S units. When we both pointed horizontal antennas at each other than it jumped up to 3-5 S units.

5 years ago I moved a couple of miles further North and slightly behind a small hill and closer to sea level and I haven't been able to talk to him from my base since so location makes a difference too

 

[CommsGuy]

Yeah, I know if I mount it horizontally it won't be good for local stuff because of the mismatched polarization. I just wasn't sure what kind of performance increase I would see over the Imax with only a 3 element beam.

 

[Marconi]

CommsGuy, this seems a hard decision to make, because you're not sure and that is understandable. The only way to be sure is to decided to do the hard work and setup your beam in the vertical with and without the Imax,

First, just to be sure you have good control over the beam.

Then add the Imax above the vertical beam.

Then, if the combination did not work as you wished or was not good performance wise, then set the beam to horizontal with the Imax above.

Then you could decide if you need another tower...which would be my best choice of all, because that it the way I preferred to do it on top of a 17' foot high roof deck on my house, even though the combination of horizontal beam and vertical GP seemed to work very good together.

Personally, I never gave a vertical beam a second thought.

This is not to say that I had no luck or bad luck with a vertical ground plane above my horizontal 4 element M104C home-brew. And, these setups of mine included an A99 and a Starduster on a 10' foot high mast where the GP radials almost touched some of the elements on the beam, due to they're being slanted down at a steep angle.

As you say the mix of horizontal and vertical is about as good as you're going to get with these antenna working close together, and that is due to the big difference in polarity, which almost makes these 2 antenna invisible to each other.

Good luck and keep us posted.