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||Extra Info:||
==============

(A) FAKE high gain antenna:

Credit to another forumer shows us FAKE 12dbi antenna he bought which perform worsen than a good 5dbi... :evil: 
(you can see the core only half distance length, upper part are all empty, and rough design just put in a metal stick...)

Image

any good 5dbi such as from level-1 (picture below) surely can outperform the fake 12dbi above...
Image

Finally come see a true 12dbi - Fiberglass omni antenna, not rubber skin material anymore!
Image



(B) Sub-standard quality antenna:

Credit to a foreign forumer who show the world the so-called 13dbi rubber duck omni antenna he bought from CN.

This is Likuda brand antenna from China, claim 13/16dbi !? With beautiful outer skin design, (the shape look familiar to you? :twisted: ) but look inside u know the truth...
Image





B] CONCLUSION:
*******************
By now you should have understood that:

• The antenna's CORE (STRUCTURAL DESIGN + CORE MATERIAL + CORE HEIGHT) produce the real effectiveness DBI. Not determined by outer length. So don't judge by looking at ads/verbal promise or antenna outer length/skin picture.
• Fake antenna made of fake core, Sub-standard class antenna made of substandard core! So beware of such beautiful antenna, or claming super high gain omni antenna, from unknown source, no marking, in bulk stock, etc...u don't know what is covered inside....

• So how to choose wifi omni antenna? :hmm: 
1) 1st consideration: Outer Length. Although been mentioned not being decisive point, but in general rule and common sense, every dbi level got it default length. 9dbi ~39cm ; 12dbi ~1.2 meter ...u can easily screening out fake antenna straight away by yourselve. For e.g. 38cm 12dbi ?!, 37cm 13dbi huh ?!, u believe???
2) 2nd consideration: The Core. This is decisive point. Ask for demo unit to view the core.
3) 3rd consideration: Brand, dbi marking, retail packing and pricing common sense. 1x dbi for RM30? u should understand.



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||Q&A section:||
=================

Q1) Why should not use over 9dbi omni antenna at home / small area?
Reason No.1: Because wifi modem/router for home users mostly does not come with higher wireless transmission power (dbm/mW) to utilise too powerful high gain omni antenna. It simply can't support to that level.

Reason No.2: Although omni antenna is 360 degree coverage HORIZONTALLY, but VERTICALLY THEY ARE NOT 360 DEGREE, AND WOULD GRADUALLY REDUCED WHEN GOING HIGHER DBI LEVEL. see pic below (released by iSigal).
Image

You can see vertical coverage drop from 40degree (5dbi) to 25 degree (9dbi), if go beyond 10dbi, it would be EVEN LOWER, just like TP-Link 12dbi only got 6 degree, so it only suitable for outdoor or if your house is as big as palace...otherwise sure be a disaster. 


Q2) Why should avoid using antenna cradle / antenna base?
Because the cradle/base use coaxial cable to connect antenna with device. And the coaxial cable cause signal loss (dbi loss), longer cable more signal loss. 9dbi - xdbi loss in cable = no more high gain antenna already, worthless!!!
Image


Q3) Why rp-sma splitter is uselesss?
WiFi is a wireless engineering, not a creativitiy toy. When the device's original circuit designed in 1T1R (1 transmission & 1 receiving with 1 antenna), no matter how many splitter u use it still run in 1T1R mode! It won't be 2T2R (if add 1 splitter to use 2 antenna), 4T4R (if add 3 splitters to use 4 antenna)... what a joke!
Image


Q4) antenna connector(RP-SMA) how look like, compatible with my devices?
from the pic below, on the right is the antenna RP-SMA connector, as long as your devices connector like the one on the left, sure fit. (generally speaking nowadays most brand do use common SMA connector already, except Linksys)
Image

edit @ 18 Jul 2011 19:21:29 by Prokek

edit @ 18 Jul 2011 19:26:19 by Prokek

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#1 By Negize on 2011-07-19 15:23