[VHFcontesting] Mounting omni loops to tower legs

[David A. Pruett]

Todd,

I have had a pair of 6M KB6KQ loops mounted on my tower for over two years 
and they seem to work fine.  These are mounted directly to the Rohn 45G 
tower leg and separated 20' apart vertically.  I can't comment about SWR 
shift because I've never used the antennas in any other location.

 From here near Detroit, the least-used direction is due north so I mounted 
the loops to the southern-facing tower leg.  No directional effects have 
been noted.

It's often surprising how well these loops work.  Mine are mounted at 50' 
and 70' and these compare surprisingly close to our 7L yagi at 
95'.  Usually, when the band is not open in a specific direction we CQ on 
the loops with good success.  This seems to work better in the June contest 
than during the January or September contests.

73,

Dave/K8CC

At 05:24 PM 3/31/04 -0600, Todd and Sandy Sprinkmann wrote:
>   On Friday, I'm going to be mounting the Par OmniLoops I have on the 
> side of my house to a better location on the side of a 100' tower.  They 
> are a 2-stack of 6m loops and a 2-stack of 2m loops.
>
>   The tower guy has concerns about how having them mounted to a tower 
> might compromise their pattern or change tuning drastically.  I called 
> Dale at Par and he said that while I might notice the resonant freq. 
> change a little, he emphasized I could mount the loops directly to the 
> tower leg.
>
>   I'm asking anyone here who has experience with this matter to share 
> their experience.
>
>   The section of tower that we would be mounting to is perfectly 
> vertical, so the loops would be directly above each other, per the 
> instructions from Par.  I plan on keeping the current spacing of roughly 
> 13' for the 6m loops and roughly 4 1/2' on the 2m loops.  I assume 
> (always a little dangerous, hi) that if I simply put the 2m loops 
> proportionately inside the 6m loops (the way I've seen rovers do it) that 
> will be fine.
>
>   Just concerned about whether the loops should be offset from the tower 
> a certain distance.  And whether if I go ahead and mount them directly to 
> the tower leg, will performance change appreciably.
>
>   Looking forward to replies as the tower guy has some time on Friday,
>   73,
>   Todd  KC9BQA  EN63ao
>
>   PS:  For those of you who have helped me with various questions over 
> the past year or so, thanks much.  The beams at 100-115' for 50, 144, 222 
> and 432 are up and ready for some spring and summer propagation.
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