High SWR on A99 after Winter Wind Storm

[Brain the Dog]

Installed a new A99 with Ground Plane Kit in the summer. SWR has been perfect, transmission and receive has been phenomenal. Have a Poly Phaser in line, using 400 Max coax.

2 weeks ago, we had a big winter wind storm. The antenna actually shifted on the mast pipe (it was clamped directly to the pipe), and is now leaning something fierce.

Then, my SWR shot up something fierce. On my Galaxy Base CB, SWR meter almost goes to 3. On my Astatic SWR meter, it goes over 3. Prior to the wind storm, the SWR was near 1.

I have my antenna-guy coming tomorrow to readjust the clamps on the mast and straighten out the antenna. Hopefully that will fix it.

But I fear the problem might be worse... any ideas?

 

[Blackcat630]

I would ditch the 3 jumbo clamps you have rigged up. 2 u bolts properly spaced is all you need. Looks like 99 shifted and dropped putting the ground plane radials against all your clamps. Recheck swr with a trusted external meter (not one in radio)... go from there...Might even look at loosing the g plane altogether... it never made a bit a difference anytime I played around with the A99s....just my .02

 

[HomerBB]

Look for broken or shorted shield to center conductor in the coax, possibly at the antenna end of the coax. The first thing I look for when SWR goes up is either a broken or grounded coax lead wire either center wire, braid, or in both.

A worn or poorly constructed coax to PL259 connection can let moisture into the coax causing shorting, too.

Look for moisture that has gotten into the bottom section but could not drain out.

Look for broken/loose wire inside the center section of the antenna.

I've seen each of these four things cause high SWR in the A99 (and other antennas, too).

 

[Robb]

Unless you put goop tape around the antenna's coax connector; then there is a fair chance that water might have gotten into the coax.

 

[Brain the Dog]

We took the antenna down. Coax is fine. Connectors are all fine.

Readjusted antenna on mast pole.

SWR is very high.

Tried it on another CB Radio. SWR still very high.

Tried new coax. SWR still very high.

We think there is something wrong with the antenna itself….

SWR was perfect before the last wind storm. Now it’s terrible!

 

[w9cll]

Probably something broke inside the antenna. Look for anything obvious and be prepared to buy a new one.

 

[Brain the Dog]

Probably something broke inside the antenna. Look for anything obvious and be prepared to buy a new one.

Yea, that's what I think. I had an A99 on the house for 25 years; that's why I went with the A99 for my new antenna. But this one failed after only 7 months.

 

[HomerBB]

Try this.
Get 2 hose clamps of a size to fit around the metal knuckles on the top and bottom of the middle section. Use a piece of wire long enough to reach between those two points -6'. Use the two hose clamps to fasten the wire along side the middle section. If things get right the single wire running inside that section has broken. I have experienced that before.
If this is the case you can run the antenna that way, or use aluminum duct tape one the outside of that section to replace the wire.

My current homebrew half wave uses a wire supported by a crappie pole as the vertcal element.

 

[Brain the Dog]

Strange.... the antenna is working fine now. SWR back down to 1. Hmmm....

 

[HomerBB]

Water/moisture getting inside the bottom section. Use a UV resistant spar varnish around where the metal and fiberglass tubes join.

 

[357]

they dont build them like they used to

 

[357magnum]

I have an A-99 live about 700' above sea level on a hill NE Winds are awful I had my top section unscrew twice and found it on the ground lock washer and all ! I put Loctite on it this time hopefully it doesn't happen again ! But I thought I had it sealed because Ice/Rain raise havoc on my SWR .After a dry day it's fine and this always doesn't happen . Next time I take down I'll re-check everything . I'm not supposed to be on a roof because I have had seizures , but I do it anyway because I'm a one man band , not too many people interested in Cb in my area .

 

[Mudfoot]

I concur with moisture.