[NLRS] Stacking distances for loopers

[Dr. Gerald N. Johnson]

On Thu, 2007-05-24 at 21:49 -0400, Glen Overby wrote:
> 
> 
> When preping for the recent SBMS 2ghz+ contest, I got looking at the stacking
> distance specs for Directive's loop yagis.  I've been ignoring these specs and
> put the antennas directly on my roof rack (about 4" from the metal roof).
> It's easy, but lately I've been wondering how bad that has hurt me?
> Directive's page on stacking dis-simmar antennas talks about how much you can
> squish antennas together, but not about possibly cutting off the bottom
> portion of an antenna's aperture.
> 
> Here's the list of stacking distances:
> 
>                         Band    #       Boom    Beam    Stacking Distance
>                                 Ele     Length  Width   E(Horiz)H (Vert)
> Directive 3318LYRM      902     18      72"     30      24      21 1/2  
> Directive 2324LYRM      1296    24      72"     27      21 3/4  19 1/4  
> Directive 1345LY        2304    45      81"     16      15      13      
> Directive 945LY         3456    45      60"     16      9.8     9
> 
> Directive's advice on stacking antennas says to use half of the stacking
> distance for an antenna when calculating stacking distance between
> dis-similar antennas.
> 
> So, my car roof is definitely in the aperture of all of these, but how much
> does that matter?
> 
> Glen, kc0iyt.
> 
You have to trade off losses from being too close to the roof and losses
of antennas from trying to trim low hanging trees. Seems to me the
losses of complete antennas from hitting trees hurts more than being
close to the roof.

73, Jerry, K0CQ