Imax 2000 Ground Plane Kit Worth it?

[Hurricane145]

Just wonder what the thoughts are on the ground plane kit for the Imax 2000 antenna. I am just wondering if it made all that much an improvement for you. Looks like the radials are 6ft fiberglass so are a bit shorter than expected so they are wound I suppose. I am used to the older CB antennas like a Super Magnum or the Hygain CLR-2 that had full length metal radials so I am a bit skeptical about any shortened radials. I suppose any radials are better than none but since the add on kit is a bit pricey I thought I'd ask about anyone's experiences with it.

 

[secret squirrel]

I can just say from observation that when I have seen IMAX or A-99 that are ran at CB shops, none of them ever had the ground plane kit attached. Also, IMAX have been replaced with Siros.

 

[sp5it]

End-fed Vertical and J-pole

Should help.
Mike

 

[Blackcat630]

Never tried the kit on the Imax but never saw any improvement on the Antron.. some swear they work.. ?

 

[The DB]

The short and quick answer is, some people notice a difference after installing said ground plane kit while others don't.

Now for a slightly longer explanation...

The ground plane kit, in and of itself, won't improve performance enough to be noticed. For that to happen you must have a problem that said kit will resolve, one example is common mode currents (which these antennas are known to have more often than others). The ground plane kit does a very good job at keeping said currents off of the outside of your coax and where you want them to be, on the antenna. That is why many antennas come with said ground plane built in to the design. When people have such problems the ground plane kit makes a world of difference when installed that they attribute to said kit.

Others, however, don't have a common mode currents problem, or any other problem that the ground plane kit will resolve. Perhaps they had an issue that they already fixed via other means (a GPK isn't the only way to fix said problems) or they didn't have a problem to begin with. They will call the product snake oil.

The product has its place, but if what your looking for is strictly better performance oriented and not resolving a problem that you might have, your looking in the wrong place...


The DB

 

[Hurricane145]

So it appears that the smart thing to do is just put it up the way it is and see how it goes before spending the extra money on it. I did have it on a 10ft pole in the backyard for a while and using it on 10 meters didn't have any problems with it.

 

[BC Coyote]

You can get rid of the common mode currents associated to an A-99 or Imax antenna by just hanging 4 108 inch wires down from the grounded base of the antenna. It creates a simple coaxial sleeve to null CMC's. No need to spend money on the so-called groundplane kit.

 

[FlatlandBusa]

I initially put up an IMAX 2000 without the ground plane kit and I was getting into the neighbors garage stereo. This is on a 10ft mast, (about 23 feet to the base of the antenna) on top of the garage with a good ground system under the entire area. After installing the ground plane kit, I am no longer heard on the neighbors stereo and the locals say I'm louder. This is a sample size of one and I put the ground plane kit on to try solving a problem and it did.

 

[unit_399]

I ran an original Antron 99 with a GPK when we lived in SoCal back in the 80s. 36' to the base of the antenna. When we moved to Georgia in '95, I put up the A99 w/o the GPK, but with a CMC coax choke. Added the GPK at a later date, but never heard any difference. I imagine the IMAX2000 would be the same.
I always heard that a vertical antenna should be mounted 1 full wavelength (11 meters/36') from the ground to the base of the antenna for best performance. When I put up my 60' tower last July, the mast between the top of the tower and the base of my antenna is 12' (72' total) or 2 full wavelengths. My antenna is a 4-element quad on the flat side. I don't know if this works for horizontal antennas, but worth a try. Anybody know ??

- 399

 

[FreshLogan]

If the MAX2000 ultimately follows the same current and voltage distribution and matching as a traditional 5/8 wave vertical the IMAX will lose its gain as it moves further from the earth below. It relies on a good ground reflection wave that is in phase with the main lobe at lower angles, from actual ground that is good like a beach for example with wet salt in it or an artificial ground.

I would use the ground plane kit for the MAX2000, it is like a "belt and braces" approach to a 5/8 wave install. Without ground planes it's a bit of an incomplete antenna and you would be better off using a 1/2 wave end fed like any 1/2 wave cb antenna.

I appreciate the MAX2000 is not quite a normal coil loaded 5/8 wave ground plane antenna though. As I gather I read on this very forum that it is a little more like a GainMaster. So I am not sure the ground planes are 100pct necessary but it will not harm your signal (maybe your wallet a bit) and quite possibly do it good.

Also depends if you have any CMC on your coax.

These days I just stay with 1/2 waves, specifically the good quality Sirio GPS 1/2 in my garden, they work well, less fussy and 99pct of the time do as well as 5/8 waves, especially those that are elevated up 20 feet or more.

 

[Dr_DX]

So it appears that the smart thing to do is just put it up the way it is and see how it goes before spending the extra money on it. I did have it on a 10ft pole in the backyard for a while and using it on 10 meters didn't have any problems with it.

If this is a "newer" Imax 2000, then it is made for 10 meters and won't tune properly for 11 meters with out the "optimizer" or a 12" extension.

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[davev8]

If the MAX2000 ultimately follows the same current and voltage distribution and matching as a traditional 5/8 wave vertical the IMAX will lose its gain as it moves further from the earth below. It relies on a good ground reflection wave that is in phase with the main lobe at lower angles, from actual ground that is good like a beach for example with wet salt in it or an artificial ground.

I would use the ground plane kit for the MAX2000, it is like a "belt and braces" approach to a 5/8 wave install. Without ground planes it's a bit of an incomplete antenna and you would be better off using a 1/2 wave end fed like any 1/2 wave cb antenna.

I appreciate the MAX2000 is not quite a normal coil loaded 5/8 wave ground plane antenna though. As I gather I read on this very forum that it is a little more like a GainMaster. So I am not sure the ground planes are 100pct necessary but it will not harm your signal (maybe your wallet a bit) and quite possibly do it good.

Also depends if you have any CMC on your coax.

These days I just stay with 1/2 waves, specifically the good quality Sirio GPS 1/2 in my garden, they work well, less fussy and 99pct of the time do as well as 5/8 waves, especially those that are elevated up 20 feet or more.

my 5/8 waves in the past have alway improved with height..modelling also shows a lower take off angle the higher you go ..the pattern only gets undesirable after 4 or 5 wavelengths high as the pattern becomes saw tooth with big nulls but the lowest lobe still keeps getting gain and lower down ..disclaimer i have not had a imax until now and its not up yet and my 5/8 wave always had fill sized radals

 

[FreshLogan]

That makes sense Dave as the artificial ground plane (attached radials) has gone upwards with the antenna.

 

[Hurricane145]

If this is a "newer" Imax 2000, then it is made for 10 meters and won't tune properly for 11 meters with out the "optimizer" or a 12" extension.

I have no idea really. Got it used a few years ago. Is there a way to tell which it is, by overall length maybe?

 

[Dr_DX]

Don't quote me but, I believe the original designed for CB Imaxx-2000's 3 sections were 8' long = 24' assembled. The new IMAX-2000 designed for 10 meters 3 sections are 7'8" long = 23' assembled.

Either way set it up, if it works on 11 meters - Great!. If it doesn't then, you know the problem.