[TowerTalk] A3 antenna problem

[Dale Martin]

A few weeks ago, on returning home from a 2-week drive to 
Spokane, WA, and back, I found some equipment in the 
house was apparently affected by a lightning strike either 
directly on the house or nearby.  Among the immediately 
noticed affected hardware were the remote coax switch 
control box (the switch turned out to be fine; the controller 
had its power transformer expanded in size by about 30 
percent--replaced it and the fuse and it works fine), and 
my Omni VI.  

I put my MFJ-259 on the antennas and they seemed okay.  
The Omni VI came back from Ten-Tec yesterday.  On 
putting it on the air, it seemed back to it's super self.  
However.....

The upper A3 at 70' on the tower seems to hear okay 
(sigs are down by about 2 s-units when compared to 
the lower A3 at 40').  But, on rotating it, there is no 
evidence of directivity.  I was hearing ZP5KO nicely on 
20m last night.  I rotated the beam from SE to NW then 
to W and S and there should have been some change 
in his signal strength; there wasn't.  10, 15, and 20m 
SWR is up to about 1.8 to 1 on the three bands.  It's 
kind of like I am listening to/operating into a dummy 
load up there.  

I hope to be able to go up there, weather permitting either 
tomorrow or Monday and check out the antenna.  
Preliminary to that, can anyone offer anything I might 
consider as the likely problem?  Blown trap(s)? 
Blown/affected balun (I used the 9 turn coax cable coil 
type--in fact, I built a new one last night in anticipation 
that it might be the problem; if not, I'll use it elsewhere)?

Has anyone experienced anything similar with their 
antennas? What was the solution? 

My plan is to simply check out the cable run back to a 
dummy load on the ground with the 259, then check out 
the balun and antenna with the 259.  If the cable run 
checks okay, then the problem will be with the antenna.  

Since I am only getting higher than normal SWR, but still 
nominal (i.e., below 2:1), and directivity seems screwed up, 
my thoughts are that the reflector or director element(s) 
may be affected.  

I'd appreciate any thoughts on this. 

Thanks in advance.

73, 
 
Dale Martin, KG5U
kg5u@hal-pc.org
http://www.hal-pc.org/~kg5u


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