Re: [amsat-bb] antenna system gain

[Scott Townley <nx7u@xxxxxxxxxxxxxx>]

Roughly 4*pi*area/wavelength^2 minus 3dB (for illumination/feed
efficiency) minus 3dB again (for linear-circular mismatch).
So area=43x58cm=.2494m^2
4*pi*area/wavelength^2=23dBi-3=20dBiL-3=17dBiC

This is also about what you'd get with a linearly polarized 60cm dish
(area=.2827m^2).  Actually the dish is 0.5dB higher.

I don't know if dBiL is a standard usage but I've seen it/used it to
emphasize the use of a linear source in a (possibly) circular
environment.

Estes Wayne-W10191 wrote:
> 
> To use Gene Marcus' S2 downlink spreadsheet effectively, I need to know the actual gain of my antenna system.
> 
> I have a 43x58cm barbeque grill linear-polarized dish with a dipole/reflector feed.  What is the gain of the antenna system, taking into account the efficiency of the feed?
> 
> Is there an online source that gives information like this without requiring extensive calculations?
> 
> Thanks in advance...
> 
> Wayne Estes W9AE
> Mundelein, IL, USA
> 
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