[amsat-bb] Re: Arecibo on 432 MHz Moon Bounce (some calculations)

[i8cvs]

----- Original Message ----- 
From: "Edward Cole" <kl7uw at acsalaska.net>
To: <w3hf at arrl.net>; <amsat-bb at amsat.org>
Sent: Thursday, April 22, 2010 5:46 PM
Subject: [amsat-bb] Re: Arecibo on 432 MHz Moon Bounce (some calculations)

Hi Ed, KL7UW

You writes:

> In fact the first gain number published over a month ago was 58 
> dBi.  Then I suppose a bunch of hams complained that they didn't 
> understand isotropic gain so the Arecibo folks kindly converted the 
> number to 60 dBd.  (i.e. unity isotropic gain, dBi=0, is what a true 
> omni-directional antenna produces in free space)
>  
> 73, Ed - KL7UW, WD2XSH/45


Ed , you have reversed dBi with dBd 

58 dBi cannot be converted to 60 dBd because the gain of a dipole 
over the isotropic antenna is 2.14 dB then 60 dBd is corresponding to
60 + 2.14 = 62.14 dBi 

By the way 58 dBd is corresponding to 60.14 dBi rounded to 60 dBi 
wich is the official gain given for Arecibo at 432 MHz

73" de

i8CVS Domenico