Need advice putting up Antron A99

[NeoHam]

I've been reading posts about this unit. I got a used A99 and have some questions.
A) It will be used on 10 meters so are there some tips (measurements) on how to start trimming it?
B) The two fiberglass sections have a metal joint in between them which has a rusty washer between them. The guy said he couldn't get them apart as is visible by the pipe wrench marks. Should I fight it to get it apart if the SWR seems ok?
C) It looks like lots of posts talk about isolating it from the mount but don't describe how. The outer 259 connector is connected to the mount so if it is isolated from the mount how will it be grounded?
D) Did I hear of some way to replace the top whip that will make it a 5/8 wave? Is that better?

 

[hookedon6]

I wouldn't try to take it apart,.... if it ain't broke,........... don't fix it.


just cut 8 inches off the tip ,it will resonate abt 28.400,....

ADD: oh jeez,............. i thought it was an IMAX ,... duh

 

[W5LZ]

Not in any particular order...

No, you can't make the 'A99' into a 5/8 wave antenna just by changing it's length. The 'rings', the impedance matching device is made for a 1/2 wave antenna, so, if you want to change it into a 5/8 wave antenna you'd have to rebuild that impedance matching circuit. It's only going to work as a 1/2 wave as it is, so don't bother.

My first suggestion would be to follow the instructions the factory gives you for doing an installation. If the manual isn't furnished (probably not) then download it from the internet. Then, it that doesn't suit you for whatever reason you can start modifying it.
The smartest way to re-tune the thing for 10 meters is by centering those rings, shorten the antenna a bit and then checking for SWR. Shorten it a bit more then recheck the SWR. That will give you an indication of how much the thing is 'moving' for the amount of 'length' you've cut off. That should give you an indication of about how much more you need to shorten the thing. Taking small 'bites' off of the antenna is a very good idea till you have some idea of 'where' it's tuned to start with. It's much easier to cut off than to add length back, right?
Once you get the length adjusted for the lowest SWR, then you can use the tuning 'rings' for fine adjustment. Typically, the SWR isn't going to be all that low, and expecting it to be 'perfect' is a bit unreasonable. THAT's when you start using the tuning 'rings' to get it under about 1.5:1. If you can get it that low, quit, that's not bad at all.
Sound like a lot of tuning? Yep, it can be, but then maybe not. That's how any/all antennas are tuned so it's about as 'normal' as it get's.
Have fun.
- 'Doc

Do that insulating from the mast by using PVC pipe, or whatever you happen to have that will be strong enough and provide electrical insulation. 'U'-bolting the thing to a PVC pipe slipped over the mast ought'a work fine. Then fix that PVC pipe so it doesn't slip down the mast.

 

[mr_fx]

Do that insulating from the mast by using PVC pipe, or whatever you happen to have that will be strong enough and provide electrical insulation. 'U'-bolting the thing to a PVC pipe slipped over the mast ought'a work fine. Then fix that PVC pipe so it doesn't slip down the mast.

I used a 3 ft wooden poll on mine