[TowerTalk] Dipole gain?

[Stan Stockton]

If every antenna were compared to every other antenna in terms of free space gain and all in the same unit of measure (say dBI) and if the numbers for gain F/B, F/R, etc were shown as average across the band then there are no additional questions to ask to determine which antenna is better or best.  

it can be confusing and misleading for someone who looks at a manufacturer's published specs when the gain shown is peak gain at some unspecified frequency in the band over ground of unknown quality and at some height that might be different than another manufacturer's specified height and unit of measure.  

Specify a "peak" front-to-back number on one antenna where at some very small frequency range there is a computer modeled back null of 35 dB and it makes it very difficult or confusing for many to compare to what may very well be a much, much better antenna pattern specified with an average, across the band front-to-rear of less than 20 dB.

If the gain and pattern numbers are all average numbers across the band and compared in free space, the task of comparing is easier.

73...Stan, K5GO

Sent from my iPad

> On Dec 11, 2014, at 3:05 AM, Steve Hunt <steve at karinya.net> wrote:
> 
> The problem with using dBd is that a Yagi's advantage over a half-wave dipole (at the same height) can vary with height! So a dBd figure is only valid at one particular height, over one particular set of ground conditions.
> 
> Steve G3TXQ
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>> On 11/12/2014 03:32, Jim Thomson wrote:
>> Just rate the yagi, or any other ant in DBD. 
> 
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