A99 VS. I MAX CHOICE AT IMPROPER HIGHT

[Stellasstillarat]

My a99 is currently on three 5' masts. it's on a tripod in my back yard on my lawn.

I could add one more 5" mast which will put the a99 about 20' from ground to feed point..

Do you think adding another 5' masts will improve performance?

I own a brand new unused I max 2000.

My plain was to remove the a99 and replace it with the I max.

If I do this I cannot add a fourth 5' mast.

So would you yourself use an a99 on four 5' masts or an I max 2000 on three 5" masts?


I know these heights fall way short of where these antennas should be mounted as hight goes but, it is what it is and is better than nothing.

I can't mount an antenna on my roof or anyehere on my home.
A telescoping mast is also out of the question.

If you were in my position would you go for the a99 on four 5' masts?

Or the I max 2000 on three 5' masts?

My hope to improve my recive. My a99 on the three 5' masts gets out well but I use and need an external preamp.
If I could gain an s unit or two on my front end would be great.
If I gained a DB on the output it would be sn added plus.
Thank. P.s. current swr is excellent. No swr problem from day one.

 

[wavrider]

Either would work.
I2K on 3 masts or A99 on four masts
performance on TX and RX about the same.

I won't go into the Current maximum of the TR signal on the two antennas 1/2 wl and .64 wl but either way will work.

With that said try the I2K on the 3 masts, then try the A99 on four masts, then scratch your head and wonder why you see no difference in performance.

 

[Robb]

I'd pick a 5/8 wave antenna (Imax 2000 or equivalent) over a 1/2 wave (A99) antenna - any day.

WIll ther be much difference? The 5/8 wave antenna has more gain (about +2db more) than an A99. The Imax has a lower angle of radiation too - which is ultimately better because you focus more of the radiated energy at a angle closer to the horizon.

Height difference is almost negligable between the two . . .

 

[Stellasstillarat]

Thanks Rob. I will go with the imax . Your explanation of the differance between the 2000 and the a99 was easy for a know nothing like myself to understand. I will post some pictures the a99 before I change it out and some with the I max in it's place. Should get it done on Sunday. I have taken notes on my locals meter readings and most of them know my received readings. I will report any changes. I'm not exspecting much better performance as to keep my expectations low. And if there happens to be a positive change, excellent!. My fingers are crossed. Thanks again.

I'd pick a 5/8 wave antenna (Imax 2000 or equivalent) over a 1/2 wave (A99) antenna - any day.

WIll ther be much difference? The 5/8 wave antenna has more gain (about +2db more) than an A99. The Imax has a lower angle of radiation too - which is ultimately better because you focus more of the radiated energy at a angle closer to the horizon.

Height difference is almost negligable betwen the two . . .

 

[fourstringburn]

I'd pick a 5/8 wave antenna (Imax 2000 or equivalent) over a 1/2 wave (A99) antenna - any day.

WIll ther be much difference? The 5/8 wave antenna has more gain (about +2db more)

Explain to us how a single vertical antenna has 2 db gain over anything.

 

[fourstringburn]

Since either antenna isn't a wavelength high off the ground, the marginal difference on paper won't make any difference to the receiver on the other end.

I used the Imax at one time because it was a simple antenna to get 10 thru 15 meters quite effectively.

A lot of us have antennas in less than ideal heights along with other compromises, but don't be too discouraged with your setup.

Make the best of what you have and what you can work with and get on the air!

 

[Rick330man]

I have both antennas. The answer depends on what you want to use the antenna for. My anecdotal experience is that the A99 is amazing for skip but the IMAX is better for local communications.

My .02 based on my experience with both.

Good luck.

 

[sdmahr]

I have both antennas. The answer depends on what you want to use the antenna for. My anecdotal experience is that the A99 is amazing for skip but the IMAX is better for local communications.

My .02 based on my experience with both.

Good luck.

Agreed. Been my experience with both as well.

 

[fourstringburn]

I'd pick a 5/8 wave antenna (Imax 2000 or equivalent) over a 1/2 wave (A99) antenna - any day.

WIll ther be much difference? The 5/8 wave antenna has more gain (about +2db more) than an A99.

Still waiting for this guy to explain his statement about how a single vertical can have any db gain over another single vertical antenna...I'm sure he has me on ignore but what a shame when someone can man up for themselves.

 

[Captain Kilowatt]

Still waiting for this guy to explain his statement about how a single vertical can have any db gain over another single vertical antenna...I'm sure he has me on ignore but what a shame when someone can man up for themselves.

He is probably just parroting the manufacturer's specs which we all know are true and accurate.

 

[Robb]

Yep . . .

 

[fourstringburn]

Typical of someone like that to do just that!

 

[Road Squawker]

... about how a single vertical can have any db gain over another single vertical antenna....

actually, it can have more (or less) depending on the installed radial system.

 

[fourstringburn]

actually, it can have more (or less) depending on the installed radial system.

That's not the argument, the radials creates an image plane and balances out the antenna.

If both antennas had the same ground plane, the fact that a single vertical antenna has no db gain over another except in Robbs' mind since he read it off the manufactures spec's which is usually advertised as DBi gain not DBd gain. I bet he doesn't know the difference.

If someone like Robb is going to make an erroneous statement, then prepare to have it challenged. At least Robb should try to vindicate himself by explaining his opinion like it was fact.

 

[vkrules]

Putting the extra 5 ft section on will make a difference to the A99.
At optimal height the 5/8th would be the better antenna , but your not going to see much difference on a guesS meter. Now at the low heights discussed, 1/2 wave at 20ft or 5/8 at 15,with pretty much the same overall height It's to close to call and will probably have more to do with objects in the antennas near field and the terrain.
My anecdotal evidence is the complete reverse to the previous two
with the imax outperforming the a99 on dx everytime , be it not by much.
How about giving it a try and report back?, would be curious to see what you get. P.S make sure you get rid of cmc before, it will skew the results .