[TowerTalk] Dipole gain

[Jim Thomson]

I agree that Free Space figures are probably the least ambiguous; but 
I'm not convinced that "averages" are very helpful!

What do we mean by "average"? What's the average of two F/B ratios, one 
of 10dB and one of 20dB?

[The average of 10dBW and 20dBW is 17.4dBW]

A "not worse than" figure across the bandwidth may be more meaningful.

Steve G3TXQ


On 11/12/2014 10:30, Stan Stockton wrote:
> 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. ##  Ok, so dbd is meaningless.   If dbi is used, then a graph of freq vs gain,and also freq vs FB,  freq vs FR, freq vs swr, etc is the only thing that would makeany sense.  Then the end user could tell at a glance what freq the peak gain is on,and how much it drops off on either side of the peak. You could easily have a yagi thathas lower peak gain, but holds a pattern better  across the entire band.  At least hecould compare 2 different yagis.  Comparing a yagi to a dipole is a moot point anyway,since most dipoles are not up at 100 feet, and none of em rotate.  If any of you have hada chance to use a rotary dipole at a decent height, its an eye opener. 15+ DB  FS is typical.Fixed dipoles vs a rotary yagi is another eye opener...when the yagi is pointed towards thenulls of the dipole. Then the differences are astounding. Jim  VE7RF