[Towertalk] 15M on C31XR

[mwdink@eskimo.com]

Hello All

Since the talk about antennas and towers seems
far and few between lately, I'm gonna throw
something out for reflection. I've tried 
asking this on the Force12 reflector a 
couple years ago before but didn't get 
much response. Since this antenna is even 
more wide spread now, Steve suggested I
try it over here.  (I also figure 
ALL of them are over here plus more.)

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~`

I have a C31XR. I'm quite happy with it but I 
get the "feeling" 15M isn't playing as well as it
could. Yes!, that's a really hard thing to quantify.

1) The antenna's SWR on 15M reaches it's minimum 
between 20.0MHz and  20.3MHz. I just use a tuner
to make the rig happy. I know that SWR is not the 
be all and end all but I know the expected minimum 
SWR for the antenna design is higher up the band.

2) After several years of competition, I just keep
getting the heck beat out of me on 15M. (I feel
competitive 10M and 20M.) When others in the area 
have high Q totals on 15, mine are always mediocre. 
I do accept the possibility that I may just be a lousy
contester too.

No, this is not a case of adjusting the infamous 
parallel wires, this antenna is feed with 3 separate
feedlines (though I am tempted to go to one feedline
just to see if things improve). I am well versed in 
all the ONE feedline techniques but it's not the
same beast.

Yes, I have made all the changes in the 
instruction book (moved driven element back, different 
hairpin coil, shortened and lengthned specified elements,
etc). I have rechecked the measurements until I am blue
in the face. I have made sure the tubing is going the
right direction (an easy mistake if not careful).

Last summer, I had it down and played with the driven element
length just to see if I could raise the frequency at
which the SWR bottom out. (I realize I may have messed up
my gain and f/b but it was an experiment). I got it
where I wanted it at ground level (about 20') but as 
soon as it went back up the tower - same result, back 
into lower 20MHz region.

So, I am looking for someone else with the same antenna,
feed with 3 feedlines, who may have experienced a similar
situation and solved it. It's not intolerable, the antenna
(at 100') works and it beats a C3S I have at 40' - it just
doesn't seem up to par with the other bands. 

I thought I would throw it out and see what floats up. 
Give us something to think about beside viruses and
insurance. :>) (NO criticism intended on ANYBODY)

73
dink, n7wa