[TowerTalk] SteppIR SWR question

[K7LXC at aol.com]

In a message dated 4/29/2011 10:59:29 P.M. Pacific Daylight Time,  
towertalk-request at contesting.com writes:

>  My 4L SteppIR with the 30/40 M trombone is on sawhorses in  the front 
yard. It was 
down to replace the driven element motor. The  climber and crane are 
scheduled to put 
itback on the tower tomorrow  morning.

>  After I replaced the motor, I ran an SWR check from  7.005 to 29.5. The 
SWR ot the 
lower end was 7.2, lowering as the frequency  went up, til at 29.5 it was 
1.0. 
Considering the proximity to ground, I  can accept that range.

>  Today ( 10 days later) I checked  again, and the SWR range had gone up 
to 8.2 to 2.2. 
Nothing has changed,  except we had rain last night, so the ground is a tad 
 damper.

>  How concerned should I be, and what would you check?  I really don't 
want to get it in 
the air and have a  problem.


        What you're looking for is  that it looks like an antenna - that 
is, that there is a nice dip somewhere.  Typically ground capacitance will 
lower the resonant frequency but if it's got a  nice dip, that's okay. 
 
        I didn't follow what 29.5  referred to. If the motors work normally 
and you've got a dip (try other  frequencies also), I'd go for it. 
 
Cheers,
Steve     K7LXC
TOWER TECH -
Professional tower services for hams
Author of the world's first tower installation book (available at  
www.championradio.com)