[TowerTalk] Dipole gain?

[Steve Hunt]

Stan,

I agree with what you say, but I'm challenging your idea of quoting an 
average. Let's say the F/R at 175 of the frequencies is 10db, and for 
the other 175 frequencies it is 20dB - what are you going to quote for 
the average F/R?

Steve G3TXQ



On 11/12/2014 11:35, Stan Stockton wrote:
> I'm talking about 350 numbers averaged, for example covering the 20 meter band - not averaging two numbers like 10 and 20 dB and I'm suggesting that because an antenna can have in excess of 60 dB of front to back at a few frequencies that the F/R number is more important.  Unless you are a direction finding person or trying to null some particular source of QRM, front to rear is a better number to look at.   The thing to avoid is for one manufacturer to claim 35 dB of F/B when in reality that occurs at 14.287 and there is no place in the band where Front to Rear is even 20 dB while another antenna is overlooked because it is shown to have 18-20 dB of F/R across the band.
>
> Stan
>
> Sent from my iPad
>
>> On Dec 11, 2014, at 4:52 AM, Steve Hunt<steve at karinya.net>  wrote:
>>
>> 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.
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