My wifi antennas

[marsbar 10]

I have made 2 antennas. 

They seem to perform ezactly the same, I got same signal strength on both.

I thought the patch,antenba would perform better but no luck.

On the patch antenna, should the plates be grounded via the 6mm center bolt?

I also made a parabolic dish, but I am not sure if the feeder horn is optimal. I started with 31mm lengt for antenna inside can, but signal got better cutting it 1mm and inserting two washers at bottom.

The USB adapter is  Deal Extreme ALFA adapter, 3070 chip but probably fake. 

I have used a 6m cat. 5 cable for USB.

Any thoughts on improvement? Dish is oval, not sure if I,got the focus point correctly.

But I get 100% 500m away signal...

 

 

 

 

 

Edited May 13, 2020 by marsbar
Images

[Admin 2545]

,,,hi bro..!!!

,,, how did you connect the antenna to the usb adapter (what type it is ... ???))...!!!!

[marsbar 10]

Here is my parabolic antenna. The focus was calculated using the with of the antenna. Length of coax center was 31mm, but cutting it to 30mm gave better signal. Then I added two washers.

Inside the water proof box there is a fake ALFA USB WiFi adapter from DealExtreme.com.

I get 100% signal from an AP 500m away. From 2km I get 75%. Unfortunately there are 40 APs and some are very strong sending out noise on the same channels... 

Any tips to improve the system? Will original ALFA adapter help?

[marsbar 10]

Unfortunately no open APs... but you know what I am thinking of. Reaver did not work... and I painted it military green for comuflage. But grey would have worked better I assume...

Edited May 13, 2020 by marsbar

[marsbar 10]

Some more info on my setup:

Cat. 5 cable length is 6m. + and - is transffered via 6 wires, USB communication on pair blue and white.

Two capacitors approx. 10uF is connected in both ends of + and - to avoid noise from power supply into communication pair.

A 1m coax is soldered directly to the tin can, center of wire is 30mm. It's 0,5mm thick.

Question: What is the best length of antenna element? I see some places Ø should be 3mm and length 31mm.

I am considering using the patch antenna instead of the cantenna for feeder. Would this improve signal?

The coax from the USB adapter to cantenna is 1m long. I need this cable because of water tight box. Antenna is placed outdoor...

Cables enters the box in the bottom to aboid water ingress. Coax cable is professional type, double outer braid.

 

Spoiler

 

 

[Admin 2545]

.... this is how a USB connector of ALFA  modem is connected to a CAT5 cable...

[marsbar 10]

I simply used an usb cable I cut, I kept the lead as short as possible. At first I used 10m. Then I,sometimes got some trouble connecting. I then reduced it to 6m. I believe 5m is the maximum length of an usb cable. 

[Admin 2545]

,,, show me what your real installation looks like...!!!

[marsbar 10]

I will post some connection pictures when I get back next week!

[marsbar 10]

Here is some more info about my setup.

When making a long range Wi-Fi connection, it's advisable to place the antenna and Wi-Fi USB adapter in a waterproof box outdoor.

However, the USB cable cannot be more than 5 m due to signal loss and voltage drop. Previously I used cat. 5 as a USB cable, but 5m is not long. It worked sometimes with 10m and 6m, but sometimes the computer would not recognice the item when you plugged it in.

So what I did was I bought two adapters from e-bay, and used some recycled cat. 5 cable. There are 8 wires in a Cat. 5 cable, 4 pairs.

One pair is used for the signal, and 2 pairs are used for plus, and 1 pair for -. Thus, voltage drop is kept as low as possible.

I have tested it with 20m cat 5 cable, voltage drop was under 0.2V so no problem. I soldered in two missing electrolytic capacitors, 10uF 16V across + and -.

The ad says maximum of 45m (150ft), but I had only use for 20m. Besides voltage drop on 45m is a bit high for the USB modem.

Tip1:

To get the cable with connector in a gland, you can cut the gland in one side. (Note glands should at all times be in bottom of a box to avoid water ingress!)

Tip2:

Peel of the outher sheath of the cable in a length of 20cm. Then you can insert the cable in a window and close it.

 

Cat. 5 cable is 0.25mm2 thick, so 20m gives a voltage dop of:

[ 0,0175 * 20 * 2 ] /0.25*3= 0,93 Ohm (2*20 because of + and - wire that are both 20m long, and 3 wires are used in paralell)

U=I*R=0,25*0,93=0,23V

USB output is normally 5.25V to compensate for volage drop in cable, so this should be ok for an ALFA adapter drawing 250mA 5V.

 

 

Edited May 31, 2020 by marsbar

[Admin 2545]

,,,, and what you want for me...???

[marsbar 10]

I am looking for ways to improve my setup.

Is there any difference in the fake ALFA and the real deal? I have to admit, I have the fake one from DX.com... (Shame on me?)

Any suggestions or is my connection lost in Noise? I get like 40 strong AP's. I get 1Mbit up and 1Mbit down.

Still, better than no internet

Edited May 31, 2020 by marsbar

[marsbar 10]

Inside my water proof box

A small hole is drilled in the bottom in case of water, its 1mm so difficult to see.

 

[clanon 246]

IMHO Hacking cards and BROWSING-DOWNLOADING cards...should't be the same...

(AR9271 , RTL8187 and RT3070) for the former and some new MIMO for the later...(No need for ALPHAS...)

 

[marsbar 10]

Any recommendations on daily use surfing cards?

[clanon 246]

All of 'em use 5ghz at the same time...dual band...you'll need to modify your antenna

https://miloserdov.org/?p=2196

https://www.wifi-antennas.com/topic/52-dual-band-cantenna/#comment-98

Edited June 4, 2020 by clanon

[marsbar 10]

The cantenna was pretty useless as feeder horn, I tried this and speed doubled and signal increased by 25%... will do a permanent change as the rain stops...

[clanon 246]

this one you could try...

i'll check the simulations...later on ...

fid24ghz.pdf

[Admin 2545]

 Clanon, no longer shows to the kid, nonsense with  biquad antenna,,,,!!!

[clanon 246]

Dragoslav Dobričić 

 is a respetable designer , engineer with several years of experience and BUILDS...check it out (before simulators) AMOS antennas vg

 

https://www.qsl.net/yu1aw/

 

 

Edited June 5, 2020 by clanon

[Admin 2545]

I did that many years ago.,,,!!!

Batwing antenna,it"s the best...

[marsbar 10]

Okay, bought a smaller waterproof box and made an LNB like setup. This eliminated my 1m antenna cable. Connection speed increased from 5mb to a whopping 121.5mbit.

Signal strengt did not improve though, 1m cable is not much loss using a high quality cable. But distortion and noise got better as a long antenna cable picks up all kinds of noise.

The problem now is the connected computer is too slow, having only a slow USB port... 

Okay, this is it, no more time to fiddle with this antenna. On to next project! ?

[marsbar 10]

Okay, bought a smaller waterproof box and made an LNB like setup. This eliminated my 1m antenna cable. Connection speed increased from 5mb to a whopping 121.5mbit.

Signal strengt did not improve though, 1m cable is not much loss using a high quality cable. But distortion and noise got better as a long antenna cable picks up all kinds of noise.

The problem now is the connected computer is too slow, having only a slow USB port... 

Okay, this is it, no more time to fiddle with this antenna. On to next project! ?

[marsbar 10]

8 hours ago, clanon said:

this one you could try...

i'll check the simulations...later on ...

fid24ghz.pdf

Actually, this bi quad antenna gave exactly same result as the patch antenna I am using now as a feed.

I am going to make more of the patch antenna, because its very solid and super easy to make! All you need is a long M6 bolt, washers, nuts.... some shhet metal that can be soldered. Tip: Look for old flat TVs in order to find sheet metal you can use. 

[Admin 2545]

,,, it might be better that way ...