Your Thoughts on an Imax 2000 + ground plane kit.

[CDX-007]

...the other reason there are so many out there:
So many people are giving them away!

Wow, free antennas ! I'll definitely take one !!!

I doubt you really want one.

I'm sure you'ld prefer an antenna.

When I traded out the Hy-Gain Penetrator for an A99, on receive it was like I rolled my RF gain back half way.

 

[Unit 194]

I doubt you really want one.

I'm sure you'ld prefer an antenna.

When I traded out the Hy-Gain Penetrator for an A99, on receive it was like I rolled my RF gain back half way.

I have owned a few A99's over the years and in my application the antennas performed well. In fact, in my opinion the A99's had better ears (RX) then my Imax 2000.

 

[lords]

strange as the Imax200 is a .64 so thats gain over the 5/8's
what you should do is just get it as a ground plain keep the signal from scattering up into the sky anyways opinions are like a$$holes we all have them...if i was to go back to fiberglass it would be the Imax2000 with the GPK

 

[Unit 194]

strange as the Imax200 is a .64 so thats gain over the 5/8's
what you should do is just get it as a ground plain keep the signal from scattering up into the sky anyways opinions are like a$$holes we all have them...if i was to go back to fiberglass it would be the Imax2000 with the GPK

The Imax 2000 is a .64 wave but the A99 is actually a half wave over a quarter wave.
I currently own the Imax 2000 with the GPK.

 

[Master Chief]

strange as the Imax 2000 is a .64 so thats gain over the 5/8's

Something to think about......

1: A .64 wave antenna is the longest element that exhibits a good gain pattern. Anything larger than a .64 wave has reduced pattern efficiency. In other words, that big gain pattern goes all to hell and you get many wave forms taking off in all directions, rather than a major lobe out towards the horizon.

2: A .64 wave is the relationship between the frequency, and the electrical length of the antenna.

3: The lower the frequency, the longer the antenna.

If you accept these facts, then this is also true......

A: If you have a .64 wave on channel 1, this same antenna will be too long on channel 40 and therefore MORE than a .64 wave. (see #1 above) This is bad.

B: If you have a .64 wave on channel 40, this same antenna will be LESS than a .64 wave on channel one (too short).

C: A 5/8 wave is a .625 wave which is only .015 wave shorter than a .64 wave. Could you even measure the gain between a .64 and a .625 antenna?

D: You would be hard pressed to tell the difference between a .625 antenna ( 5/8 ) and a .64 wave antenna.

I've said this over and over and over! A 5/8 is a 5/8 is a 5/8! The magic is in the matching network. Some matching networks have less loss than other matching networks! Why does everyone refuse to think about the matching network and insist that their 5/8 works as well as another 5/8. If both had the same matching network losses, than this would be true.

The problem with the iMAX 2000 is the lossy matching network. The most efficient matching network currently on the market is the I-10K, which is why people see an increase in transmit and receive signals.

Everything works. Some things work BETTER. The iMAX 2000 has the same type lossy matching network as the A-99, but should perform better because of the longer element.

Lastly, stick with a 5/8 wave antenna and don't get sucked in to the .64 wave issues (unless you are building a SINGLE FREQUENCY antenna, like the broadcast people do).

 

[CDX-007]

I doubt you really want one.

I'm sure you'ld prefer an antenna.

When I traded out the Hy-Gain Penetrator for an A99, on receive it was like I rolled my RF gain back half way.

I have owned a few A99's over the years and in my application the antennas performed well. In fact, in my opinion the A99's had better ears (RX) then my Imax 2000.

Oi-vay

strange as the Imax 2000 is a .64 so thats gain over the 5/8's

Something to think about......

1: A .64 wave antenna is the longest element that exhibits a good gain pattern. Anything larger than a .64 wave has reduced pattern efficiency. In other words, that big gain pattern goes all to hell and you get many wave forms taking off in all directions, rather than a major lobe out towards the horizon.

2: A .64 wave is the relationship between the frequency, and the electrical length of the antenna.

3: The lower the frequency, the longer the antenna.

If you accept these facts, then this is also true......

A: If you have a .64 wave on channel 1, this same antenna will be too long on channel 40 and therefore MORE than a .64 wave. (see #1 above) This is bad.

B: If you have a .64 wave on channel 40, this same antenna will be LESS than a .64 wave on channel one (too short).

C: A 5/8 wave is a .625 wave which is only .015 wave shorter than a .64 wave. Could you even measure the gain between a .64 and a .625 antenna?

D: You would be hard pressed to tell the difference between a .625 antenna ( 5/8 ) and a .64 wave antenna.

I've said this over and over and over! A 5/8 is a 5/8 is a 5/8! The magic is in the matching network. Some matching networks have less loss than other matching networks! Why does everyone refuse to think about the matching network and insist that their 5/8 works as well as another 5/8. If both had the same matching network losses, than this would be true.

The problem with the iMAX 2000 is the lossy matching network. The most efficient matching network currently on the market is the I-10K, which is why people see an increase in transmit and receive signals.

Everything works. Some things work BETTER. The iMAX 2000 has the same type lossy matching network as the A-99, but should perform better because of the longer element.

Lastly, stick with a 5/8 wave antenna and don't get sucked in to the .64 wave issues (unless you are building a SINGLE FREQUENCY antenna, like the broadcast people do).

There's about 2.4% difference in length from a .625 (5/8 ) to a .64.

There's about 1.8% difference from 26.965 (ch.1) to 27.405 (ch.40).

I believe it's more of an issue of the Take-Off-Angle of the antenna design. The .64 will hug the Earth a bit longer/ further which could be a bad thing if one lives in a canyon, a good thing for those in the flatlands.

For 'Canyonites' buy a Starduster!

strange as the Imax200 is a .64 so thats gain over the 5/8's
what you should do is just get it as a ground plain keep the signal from scattering up into the sky anyways opinions are like a$$holes we all have them...if i was to go back to fiberglass it would be the Imax2000 with the GPK

The Imax 2000 is a .64 wave but the A99 is actually a half wave over a quarter wave.
I currently own the Imax 2000 with the GPK.

I wonder what possible gain you might see if you used four 8' 8" guy wires, each to an insulator, as radials instead?


73

 

[automan4025]

Good,bad or what.............

I have the Imax 2000 and it works great. I just took the ground plane kit off and it works the same as it did before. Great antenna for the price.

 

[CDX-007]

Good,bad or what.............

I have the Imax 2000 and it works great. I just took the ground plane kit off and it works the same as it did before. Great antenna for the price.

Why not try the guy wire radial mod with some long distance ground wave contacts to see if you notice any improvement?

8' 8" from the top of the aluminum mount to an insulator.

Could also help prevent RFI in the house / neighborhood.

 

[hotrod]

well after owning both the a-99 and imax .gotta say the imax had a 2s unit on locals.i spent all day one year doing many
unscintist tests.on a stock grantxl with these antenna and lmr400 coax hooked to each one at a time.so everything
was the same expect the antenna.all the locals i know personally and i had them call me back with the results
only 1 saw very little change.however he was also the closest
to me.which would explain that.on recieve end both were equally noisy and i saw a 1-2 s unit increase with the imax
none of these tests were done with the gpk for either.
the a99 is a good antenna for starters or if ya wanna something more affordable without losing alot of performance
imho i dont see were adding a gpk would make a difference
in either.definately not 40bucks worth :roll:

 

[CDX-007]

well after owning both the a-99 and imax .gotta say the imax had a 2s unit on locals.i spent all day one year doing many
unscintist tests.on a stock grantxl with these antenna and lmr400 coax hooked to each one at a time.so everything
was the same expect the antenna.all the locals i know personally and i had them call me back with the results
only 1 saw very little change.however he was also the closest
to me.which would explain that.on recieve end both were equally noisy and i saw a 1-2 s unit increase with the imax
none of these tests were done with the gpk for either.
the a99 is a good antenna for starters or if ya wanna something more affordable without losing alot of performance
imho i dont see were adding a gpk would make a difference
in either.definately not 40bucks worth :roll:

Same here, except even Stu (Novakor) saw 2 S-units difference and our antennas were only 165 paces apart.

 

[mrbooker]

Ground plane kit raised swr

I put up my Imax2000 and ran it for about 3 months without my GP kit. SWR was 1:1 After installing my GP kit , swr went to 1:5. Tuned and re tuned imax but never got swr back down under 1:5. Un installed GP kit and swr went back down to 1:1. ... anyone have a solution?????