Link Budget

[yukondan]

Just a quick reminder here. When I do a link budget ...let's say I have 30dBm from my transmitter , do I add my antenna gain in dBd or dBi , I understand what both are refering to (gain over a dipole gain over isotropic) I just can't remember which to use in a link budget ! for the record I am going to say dBi!!

 

[robertjo24]

FYI…
When I do path calculations, my software lists the antenna’s data in both dBd and dBi, but uses the dBd for its calculations. I believe this is fairly standard across the board.
I think most use the actual loss rather than the theoretical loss for calculations and expression.
Just my $0.02 worth.

 

[yukondan]

what is acceptable in terms of return loss?? 10 dB 5 dB ?? just looking for a benchmark for testing antenna/cables thanks

 

[Higgler]

You are right, it's dBi because you want effective radiated power or Power X gain (dBi).

Once you do your perfect calculations, wind movement, birds, VSWR's, rain, etc. sure can make your received power drop.

kch

 

[johnwiss]

I think dBi should be about 2.5 dB less than dBd--is that what the specs show??