[TowerTalk] 6 meter antenna comparisons

[Jim Brown]

On 4/13/2013 4:19 PM, Steve K7AWB wrote:
>
> Anyone have any opinions on which one to use? 

Hi Steve,

Some thoughts. First, the table is the result of a MODEL, not a 
measurement.  Second, gain is given as a single number, without 
reference to bandwidth nor beamwidth.

Third, it's long been well known that given equally good (well 
optimized) design, the primary influence on gain is the boom length. You 
can tweak element lengths and spacing to trade a bit of gain for a bit 
of F/B, beamwidth, or bandwidth, but I'd bet that most designers are 
trying for close to the same set of compromises. In the table, you could 
draw a pretty straight line on a scatter graph of gain vs boom length, 
with no data point more than about 0.5dB off the line. I would tend to 
view a table like this as "truth test" -- if the advertised gain doesn't 
correlate pretty closely with boom length, someone's probably lying. :)

There is, of course, the issue of build quality, ruggedness, efficiency 
of the matching system, support by the manufacturer, etc.

73, Jim K9YC