Posts Tagged ‘diy’

Curtain Quad Panel Wifi Antenna 18dbi

Thursday, September 27th, 2007

Are You remember this one :


This looks very crazy, oddly promising 18 dbi gain.

BUT now there are more info about this, as promised by admin of the GUW forum.

Here is all info in spanish :

The author of this one is Ross Anderson and the original idea for this antenna is from 1984 year 🙂 the good thing is that all the information about this one is here.


There is interesting version of this antenna build by the author. On his site he describes the how to build this panel antenna from zing fence. The original 2400mhz version is here :

The idea and the info :

Here some pictures from the em simulation from GUW site :

18dbi wifi panel antenna

So as I see this, I can accept that this antenna works. On the site is said that this antenna outperform many commercial ones.

The diagram of this antenna and look from in front :

18dbi wifi panel antenna cheap homemade diy diapositiva5.jpg

More pictures of this antenna build and tested for 1296Mhz and 2400mhz :


Interesting about this is the using of speaker wire for matching transformer :

“… Solder a 1+ inch piece of speaker wire to the N connector. One wire goes to the center pin; the other wire to the outside part of the connector. I drilled a small hole in the connector flange for the wire to be inserted into and soldered in place. Leave about 3/4 inch of insulation on the speaker wire (as measured where the two wires are together). This is the transformer, transforming the antenna impedance to about 50 ohms.”

There is also PDF tutorial on the GUW site : guw panel 18dbi.pdf

So this is promising design which I should test soon too. Will be interesting to find out will this design works if it is printed on PCB?

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 : and

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.

Slot Length
2.15 l
Slot Width
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


Here is some pictures from


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.

DIY Hi-Gain Antenna on Cheap ;)

Friday, August 31st, 2007

Very Cheap Dipole feeders – they are easy to be build and you do not need a lot or expensive materials. Everything here can be made from wire or scrap /I watch too much scarpwars on Discovery channel 🙂 /

I found some very interesting looking feeders for dishes – VERY cheap to make, first is made only from feeder line 🙂 or simple coax.


A simple dipole feed. Good solution to illuminate parabolic constructions (solid, grid etc.) Heliax holds the dipole, as well as feeds the N-type female connector to the back. Tests shown 4 dBi (against Lucent 24 dBi parabolic grid). “

Second is Russian of course

Name of the file is interesting too D_Linc3_008.jpg


Interesting materials – onli several pieces of pcb board are used – very good.

From the same forum are these too –

d1.jpg d2.jpgdipole_construction.gif

Last pic is from

And for the end howto make wire reflector or DIY Parabolic Grid Reflector

diy reflector

Info is from this :

19dbi gird blueprint :

19dbi gird blueprint

For me is easy to buy small offset dish – 80cm is around 10 to 15 Euros here.