dslreports logo
site
 
    All Forums Hot Topics Gallery
spc

spacer




how-to block ads


Search Topic:
uniqs
6549
share rss forum feed


seagreen
Premium,Mod
join:2001-05-14
out there

Forum FAQ - pending feedback...

For this item: »Wireless ISP FAQ »How is antenna gain (dBi) measured and used?

said by feedback :
please provide with the formula to calculate the gain of the antenna in dBi .....
Anybody have this formula so it can be added to the FAQ?

LLigetfa

join:2006-05-15
Fort Frances, ON
kudos:1
IMHO there is no simple formula that an end user could use. That is in the domain of antenna design modelling software. For more info see:
»www.si-list.net/swindex.html

P.S. The topic is too detailed to fit within the limited scope of a FAQ.
--
Strange as it seems, no amount of learning can cure stupidity, and formal education positively fortifies it. -- Stephen Vizinczey


John Galt
Forward, March
Premium
join:2004-09-30
Happy Camp
kudos:8
reply to seagreen
Make reference to this document:

»arxiv.org/PS_cache/physics/pdf/0 ··· 23v1.pdf
--
A is A

lutful
... of ideas
Premium
join:2005-06-16
Ottawa, ON
kudos:2

1 edit
The classic W1GHZ antenna design handbook ( »www.qsl.net/n1bwt/contents.htm ) provides gain theory and calculation for many antenna types used by WISPs.


seagreen
Premium,Mod
join:2001-05-14
out there
reply to John Galt
said by John Galt:

Make reference to this document:
Yikes - I haven't seen stuff like that since calculus in college. *shudders*

I'll probably just link the responses in this thread to that FAQ item.


Killer Max

@rr.com
reply to seagreen
said by seagreen:

please provide with the formula to calculate the gain of the antenna in dBi ...
Not sure that is even a valid question. The gain of an antenna is a factor of it's physical construction, and not something that would be deduced by a mathematical formula. The amount of gain and the shape of the envelope are factors of reflective surface area and it's relative angles, active element characteristics, apex distances and etc. There are certainly formulas used at the manufacturing level as guides for a new design, but the actual gain of an antenna is authoratively determined by radiation pattern measurements in a laboratory environment. If the question was actually "What is the formula to determine the difference between DBi and DBd", the answer is add 2.2 to the DBi value.


seagreen
Premium,Mod
join:2001-05-14
out there

1 edit
That wasn't my question but rather feedback left in the FAQ....

I kinda figured it wasn't going to have a simple answer and since I don't what the intent was of the person who asked I thought I'd throw it out to you guys to talk over.