[TowerTalk] 160m Inverted L

Rob Atkinson, K5UJ k5uj at hotmail.com
Mon Jul 23 13:14:05 EDT 2007


I read a broadcasting industry study last year (I'm sorry but I stink at 
remembering sources so I can't cite it unfortunately other than to say I 
think it was in IEEE transactions on broadcasting) that compared field 
strengths for different length medium wave vertical radiators with different 
ground systems in terms of no. of radials and lengths.  There were 
combinations evaluated using:  45, 90, 120 and 180 degree verticals, and 45, 
90 and 180 degree length radials in numbers of 60, 120 and 240.   The 
conclusion I came away with from looking at the measurments was that while 
height of the vertical is definitely a factor, the ground system was the one 
single thing that made the biggest difference in field strength.    The f.s. 
of a 45 degree vertical was not much less than a 90 degree all other things 
being equal.   but a 90 degree stick with double the no. of radials had a 
substantially stronger field.   In other words, it is nice if you can go up 
more than 50 or 60 feet but if you can't, then put down at least 60 radials 
(90 if you want to feel good) and don't worry about the lack of 20 feet of 
vertical height.

73,

rob / k5uj

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