[Elecraft] dBi dBd correction

[Joe Subich, W4TV]

> If my recollection is correct, 0 dBd is 2.15 dB greater than 
> 0 dBi in the dipole's favored directions (perpendicular to the 
> radiator).

Only in free space ... when a horizontal dipole is placed 
above ground all of the radiated power is concentrated in 
one hemisphere.  Since both the E and H fields are confined 
to the single hemisphere, the resulting "gain" is 6 dB more 
than the free space gain or 8.17 dBi (1.25 + 6.02).  

73, 

   ... Joe, W4TV 
 


> -----Original Message-----
> From: elecraft-bounces at mailman.qth.net 
> [mailto:elecraft-bounces at mailman.qth.net] On Behalf Of Ron 
> D'Eau Claire
> Sent: Wednesday, May 06, 2009 5:32 PM
> To: don at w3fpr.com
> Cc: elecraft at mailman.qth.net
> Subject: [Elecraft] dBi dBd correction
> 
> 
> Yeah, I misread the rule. I thought the rule was saying a 
> dipole was 0 dbi, not 0 dBd! Didn't make sense to me.
> 
> Gus, KB0YH also caught my mistake.  
> 
> Tnx for un-kinking my brain Guys!
> 
> 73,
> 
> Ron 
> 
> -----Original Message-----
> 
> Ron,
> 
> The FCC regulations for 60 meter power is referenced to the 
> maximum lobe 
> of a dipole.  Sooo --
> That should be "0 dBd" (gain/loss relative to a dipole) 
> rather than "0 
> dBi" (gain relative to an isotropic radiator).
> If my recollection is correct, 0 dBd is 2.15 dB greater than 0 dBi in 
> the dipole's favored directions (perpendicular to the 
> radiator). For those not familiar with an isotropic radiator, 
> it is a point 
> construct in free-space that radiates equally in all directions.
> 
> 73,
> Don W3FPR
> 
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