[TowerTalk] Fwd: Dbi vs DBd

[Jim Lux]

-----Original Message-----
>From: Bill Aycock <billaycock at centurytel.net>
>Sent: Nov 3, 2009 7:23 PM
>To: AD5VJ  Bob <rtnmi at sbcglobal.net>, "\"'Tower Talk'\"" <towertalk at contesting.com>
>Subject: Re: [TowerTalk] Fwd:  Dbi vs DBd
>
>Bob-- In the design process, it does not matter, so long as the designer 
>understands and uses a consistent set of methods and units. Only the 
>designer must be satisfied.
>>
>----- Original Message ----- 
>From: "AD5VJ Bob" <rtnmi at sbcglobal.net>
>To: "'Roger (K8RI)'" <K8RI-on-TowerTalk at tm.net>; "'Tower Talk'" 
><towertalk at contesting.com>
>Sent: Tuesday, November 03, 2009 8:44 PM
>Subject: Re: [TowerTalk] Fwd: Dbi vs DBd
>
>
>> What about antenna design applications, do they give you a choice or one 
>> or the other as a standard?


I would venture that the only substantial users of dBd are hams and possibly marketeers. The pro modeling tools (NEC and it's ilk, the FDTD programs, etc.) all use dBi.

The problem comes with defining the "d" in the "relative to a dipole".. do you mean relative to the gain in the same direction, or relative to 2.15dBi, the peak dipole gain? At least the isotropic antenna (while impossible to actually realize) has a uniform definition.