Basic Antenna Question

• Aug 20, 2007

• #2

logbook

Electrical

Sep 8, 2003

764

GB

http://en.wikipedia.org/wiki/Antenna_gain

This should answer your question.

 

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• Aug 20, 2007

• #3

logbook

Electrical

Sep 8, 2003

764

GB

Additionally, you should understand that a higher gain antenna (larger dBi figure) means the antenna is more directional. If that is what you want it is better.

If you want to receive from all directions you want a lower gain antenna!

 

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• Aug 20, 2007

• #4

Higgler

Electrical

Dec 10, 2003

997

US

Antennas are like those small flashlights with the zoom capability. High gain is small bright spot, low gain is wide spot. They use the same battery so only the focusing is changing.

from one point to another high gain is good, more signal gets to the other end. Cell phones have low gain and transmit everywhere because you don't know where the cell towers are located.

Lots of good reading material out there. Just Google antennas.

kch

 

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• Aug 22, 2007

• #5

DaveAA1A

Electrical

Aug 17, 2007

5

US

cam,

DBi alludes to a radiator which illuminates equally in all directions. Equal apeture...
The 'i' stands for Isotropic, the closest demonstration being a lightbulb but even the base keeps it from being a perfect ISOTROPIC radiator...
A simple dipole has some gain over a isotropic because it is somewhat directional...
The isotropic number is higher than a dipole so 'looks' like a better antenna...
It's all relative to whichever system you keep your numbers in...

73s from DaveAA1A

 

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