Posts Tagged ‘polarization’

Multipolarized wifi Antenna

Wednesday, October 10th, 2007

All my links for antennas whit multi polarization

List of all products of wifi-plus : www.wifi-plus.com/antennas
Lets begin whit this page here : http://www.dslreports.com/forum/remark,13636968
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You can find comparison of 5dbi multi polarized to 7dbi rubber duck : www.zero13wireless.net
Tested model is : MP 5 OMNI 5dBi CHP

Dimensions of the 17dbi model :
antena_multipolarizada_17dbi.jpg
http://www.zero13wireless.net/foro/showpost.php?p=5579&postcount=2

Here a tread whit all the dimensions and tests, also home build versions of 17dbi antenna :
http://www.zero13wireless.net/foro/showthread.php?t=881

Here You can find a test between 12dbi MP and 14 Yagi in the forest :
http://www.zero13wireless.net/foro/showthread.php?t=1750

MP 12dbi The same as 17dbi version only shorter :
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http://www.zero13wireless.net/foro/attachment.php?attachmentid=1115&d=1185362179

Pictures of 12dbi version
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Pictures of Bullet Omni 3dbi (2.4/5.X GHz) and Omni 5dbi (2.4/5.X GHz)
http://www.zero13wireless.net

In the net there was also some pdf pathent files one is here : click

Alford Slot – Horizontal Omnidirectional Antenna

Thursday, September 13th, 2007


Alford Slot – Horizontal Omnidirectional Antenna working on HAM band – somewhere around 2.3ghz or 13cm.

Whit several words what is Alford Slot : this is circular pipe whit ONE LONG slot on it, feed by coax line coming from inside the tube.

Here is some photos :

Alford SlotAlford Slot

note pics are for lower frequency – typically for 1200Mhz, second shows that for low band this antenna can be made even from wire

The tutorial how to make this antenna is on this site : http://www.g8ajn.tv/23cms.htm and http://www.k5rmg.org/Alford-slot.html

Interesting about this antenna :

Omnidirectional paten

Horizontal polarization

Physically its circular – for me its important omni antenna to be circular – do not ask 🙂

Interesting feeding point of slot.

The design of this antenna is based on several tables or ready pre-calculated values.

Freq.
(MHz)
Slot Length
2.15 l
(inches)
Active
Circum.
0.40l
(inches)
Slot Width
0.016l
(inches)
Final
ant.
dia.
(inches)
902.1 28.25 5.20 0.190 ~1.72
1296 20.125 3.910 0.170 ~1.3
2304 10.688 2.120 0.090 ~0.7

active-circumference.gif

Here is some pictures from www.g8ajn.tv

cameradownload-071.jpgcameradownload-072.jpg

cutting the slot and ready feed points

Here is the interesting part – building of the feeding point I was really surprised :

cameradownload-073.jpg cameradownload-074.jpgcameradownload-075.jpgcameradownload-078.jpgcableties.jpg

Only this is for separate post ! 🙂 This showing how to make impedance matching directly whit coax ! So on this on the last picture coax line is impedance matched.

cameradownload-082.jpg cameradownload-080.jpgcameradownload-079.jpg

Next is connecting coax to the slot, second picture is fine tunning, and the third is preparing for mounting. Tunning is made by extension of the slot.

Go on the sites shown up and read the instructions for building this ones You may find thing that I missed.