Recommend Ground Plane Kit For Imax 2000?

[Wire Weasel]

Looked a bit for other existing threads and didn't see one.

Anyone use an Imax without the GPKit and then add it later? Significant improvement?

TNX

 

[Robb]

Nah, I never got the GPK for my IMAX.
Seems to work extremely well with either DX or local - as is.
I don't know if spending an extra $50 will be worth the 2db gain.
If you use it, I'll consider your response if I am going to buy one.

BTW - Would the A99 GPK work on the IMAX? I know they attach differently; but can they be adapted? I have a friend of mine that has one - that wants to get rid of it...

 

[dudmuck]

Significant improvement?

Depends on what you're trying to improve. If your problem is TVI or the like, then the GPK is a big plus. Either that or an ugly balun coax choke.
The antenna needs some kind of counter-poise. It'll use whatever metal is connected to it, coax shield or mast.

Even if you dont put on the GPK, you should at least consider the ugly balun choke especially if you run Big Watts. Only to prevent RF on the outside of coax, which causes TVI.

 

[BOOTY MONSTER]

you could make one out of speaker wire and pvc pipe and attach it to the 2000s mounting plate . if going with store bought i like the looks of the 3 or 4 sloped starduster type . much better looking than the saw horse looking one made for the 2000 . but looks arnt everything . insulating the antenna from its mast and earth ground and using a coax choke seems to be the best way to install them .

http://www.worldwidedx.com/cb-anten...endfed-antennas-their-support-structures.html

 

[Wire Weasel]

Thanks everyone. This has led to some excellent info. Thanks to the Botty Meister for the great linky here on the site. WWDX comes through again.

I've sprung for the GPK and will isolate the antenna system from the metal mast.

Have recorded the normal signals from about 10 locals all around me. Will compare the results. Also will watch the TVI I'm getting from another current thread on other forum here. Antenna base will remain at same height as now.

 

[BOOTY MONSTER]

thanks for making note of how its doing for befor and after results . i look forward to them .

 

[Wire Weasel]

While I'm waiting for the new stick, I'm going to yank the existing vertical down tomorrow morning and isolate it from the mast.. Then put 'er back up and see if that cleans up my TVI

I'm actually gonna be pretty pissed if this works..ha ha. I've been putting up with alot of crap a long time just to see it all go away by something as simple as this. Dammit boy!

 

[Robb]

What kind of material are you going to use to isolate it from the mast?
A piece of rubber radiator hose?
Or - ???

 

[Wire Weasel]

I have tire inner tube rubber on hand. Will use several wraps. Off to do it now......

 

[HiDef]

I have tire inner tube rubber on hand. Will use several wraps. Off to do it now......

Black rubber is a very poor insulator for R.F.

 

[Wire Weasel]

Black rubber is a very poor insulator for R.F.

Parasitic effect is not what is being discussed here. This is direct coupling. I assure you that 4 wraps of this think sheet rubber is more than adequate separation. Parasitic isolation is only accomplished by using a non-conductive mast like plastic pipe.


Well the "mod" is done and there is no difference in my TVI. Have a dozen different torroid and ferrite chokes coming and I'll distribute those around on the TV & radio in the next attack :sad:

 

[HiDef]

Parasitic effect is not what is being discussed here. This is direct coupling. I assure you that 4 wraps of this think sheet rubber is more than adequate separation. Parasitic isolation is only accomplished by using a non-conductive mast like plastic pipe.


Well the "mod" is done and there is no difference in my TVI. Have a dozen different torroid and ferrite chokes coming and I'll distribute those around on the TV & radio in the next attack :sad:

If you are using rubber for an R.F. insulator you have achieved DC isolation but not R.F. isolation. Materials don't care about semantics.

What is parasitic isolation? The term doesn't appear in any of my reference books.

If you are talking about adding radials to a "Big Stick" design antenna the current will flow into the properly placed resonant radials without insulating anything. Doc correctly stated this before. Same principal as a fan dipole.

 

[Beetle]

There are a LOT of rubber sheet formulations that contain carbon black and are quite conductive. I'm not saying that was what you used for your insulating of the antenna, but from the time I saw rubber conducting electricity (about 60 amperes' worth over a three-foot length) on board a Navy ship many years ago, I have always double checked!

Same thing goes with just about any "flat black" paint.

 

[Wire Weasel]

The Imax w/ GPK is up and successful! The TVI is reduced but not eliminated. Signals both ways to all the locals is up 1.0 - 2.5 S units. Good investment for the gain received.

 

[BOOTY MONSTER]

good to hear you had positive results on both TX and RX .
can you tell any difference in your noise floor/static levels ?