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Re: [TowerTalk] Dipole gain?

Subject: Re: [TowerTalk] Dipole gain?
From: Steve Hunt <steve@karinya.net>
Date: Thu, 11 Dec 2014 14:03:24 +0000
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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@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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