Wifi Antenna Modification

[techno13th]

Hello,

is it possible for me to use uhf/vhf outdoor tv antenna for Wireless Wifi Router ??

I'm wondering if this thing can be done...

 

[ronsimpson]

TV antennas are usually 300 ohm and the WiFi antenna is 50 ohm.
TV antennas are broad band while you should use a narrow band antenna.
Other wise it will work.

 

[techno13th]

So, other than cracking into the firmware.. what is the best way to extend the range.. I know few ways such as cantenna, windsurf dish,etc..
Any ideas?

 

[crutschow]

A TV antenna wil work very poorly, if at all, since WiFi is 2.4GHZ and TV antennas only go to a maximum of 890MHz.

Changing the firmware will have no effect on range. If you Google "extending WiFi range" you will get many hits.

 

[ronsimpson]

There are many antenna designs out there.
http://www.freeantennas.com/projects/template/
I built something like the above only 2X the size. I used flat copper or sheet metal. I talk 5 miles to town every day. It will not work in the rain/fog. Snow is OK. That is because water resonates at 2.4ghz.
**broken link removed**

 

[Reloadron]

I have had pretty good results using the various cantenna designs that, as can be seen are numerous with a Google of Cantenna. However, to answer your question, no an antenna designed for UHF TV will not work.

Ron

 

[4pyros]

You need a yagi antenna. You can make it from parts of a UHF antenna.

Andy

 

[Sceadwian]

4pyros, Cantenna's will outperform Yagi's and have a simpler construction. Biquads are a good choice as well because they're flat.
https://www.engadget.com/2005/11/15/how-to-build-a-wifi-biquad-dish-antenna/
Note the clever use of a used satellite dish to further increase gain. The dish is not required you should get a good 9-12db of gain using just the straight biquad. Cantenna's will do the same but the dimensions of the can are actually quite important, and finding a can with the perfect diameter and proper length is not that easy.

Just a quick note, don't skimp out on the wire you use, the bandwidth of the element is affected by the thickness of the wire, so the thicker the better.

 

[xopenex]

beef up wifi

hi guys, new here

i am looking to beef up my wifi tx and rx, saw the recent action on this post, so thought i would chime in.

i just learned today that there are many things which run on 2.4ghz, telephones, wifi, remote control airplanes/helicopters, etc. is there a way to use components from other 2.4ghz devices to connect to my laptop wifi auxillary antenna connector?

i was also wondering what power (wattage) that a linksys operates on? the reason i ask this is because ive been trying to figure out a 1 watt amplifier for my wifi and it looks as if the best thing to do is mod a linksys firmware, which i have done in the past, but i would like to build something more portable.

ive seen the cantennas and others similar, but what i found that was more of what i want is the wave magnum wifi amplifier! (i would just rather build it, cheaper, plus i love a good project!)

thanks

 

[Sceadwian]

Amplifiers for that spectrum are illegal =) This is why it's the unlicensed band.

 

[xopenex]

so this is illegal? https://www.radiolabs.com/products/wireless/wave-magnum.php

 

[xopenex]

that biquad is awesome! does it have to point directly at the source? thanks

 

[alec_t]

If you have a social conscience, bear in mind that by boosting your own wi-fi signal you risk creating interference on neighbouring wi-fi networks.

Alec

 

[Sceadwian]

Yes, Biquads are HIGHLY directional, at 15degree's it's no better than a dipole, around 3db gain, at 90 degrees (directly facing it's target) the gain is almost 12db. ALL atenna designs have to sacrifice gain for directionality, they can not create power they simply focus it. Double Biquads are supposed to a few db better, but I think construction techniques are critical when you're talking about that much gain.

https://www.lecad.fs.uni-lj.si/~leon/other/wlan/biquad/index.html

 

[davenn]

so this is illegal? https://www.radiolabs.com/products/wireless/wave-magnum.php

You would need to check with the laws in your own country. For ISM bands the transmitter and EIRP power levels are governed reasonably tightly. They (ISM equip), in most cases, are supposed to be low power and short range devices.

You may find that that 1W amplifier is legal in the USA (where it is manufacturered) but not in some other country.
there are all sorts of weird and wonderful variations
1W TX may be allowed but a max of a 5dBi gain antenna etc

You really need to read up on the rules in your country for ISM band usage

else we are all just guessing

cheers
Dave

 

[ronsimpson]

2.4ghz is very much line of sight. The two antennas must see each other. There can not be one tree in the way.

 

[Sceadwian]

ronsimpson are you feeling okay? If 2.4ghz is line of site then how do I get wi-fi on my sun porch when the access point is in a sealed cabinet with 2 drywall partitions between it? You statement is both dead wrong, and misleading you should edit it to reflect that.

 

[Nigel Goodwin]

ronsimpson are you feeling okay? If 2.4ghz is line of site then how do I get wi-fi on my sun porch when the access point is in a sealed cabinet with 2 drywall partitions between it? You statement is both dead wrong, and misleading you should edit it to reflect that.

Life isn't as clear cut as that - he's perfectly correct when he says that 2.4GHZ is VERY much 'line of sight' - it will penetrate some obstacles though, as long as they aren't too 'solid' (but range will be severely crippled). His example of a tree would completely block 2.4GHz, it's very solid, and full of RF absorbing water.

Anything VHF and above is 'line of sight', and the higher you get, the worse it is.

 

[Reloadron]

Sceadwian, I think what ronsimpson was getting at is that a frequency of 2.4 GHz is considered LOS (Line Of Sight) for all intensive purposes. For example:

What Are Microwaves

Microwave frequencies range from 300 MHz to 30 GHz, corresponding to wavelengths of 1 meter to 1 cm. These frequencies are useful for terrestrial and satellite communication systems, both fixed and mobile. In the case of point-to-point radio links, antennas are placed on a tower or other tall structure at sufficient height to provide a direct, unobstructed line-of-sight (LOS) path between the transmitter and receiver sites.

The above quotation was taken from here.

The ARRL also has a take on it that goes like this:

Line-Of-Sight Propagation
Line-of-sight propagation occurs when signals travel in a straight-line form the transmitting antenna to the receiving antenna. These signals, also know as direct waves, are used mostly in very high frequency (VHF), ultra high frequency (UHF) and microwave ranges. The signals you receive from your local television stations and FM radio stations are examples of direct waves. Two-way radios, like police and fire departments and Amateur Radio operators use, is another good example of line-of-sight propagation. When transmitting on a local repeater frequency, direct waves generally travel in a straight line to the repeater. The repeater then retransmits the signal in a straight line.

The above quotation was taken from here.

While WiFi runs in a 2.4 GHz band, a frequency considered to be LOS that does not mean that minor obstructions like a drywall wall will totally block a signal when the distance between devices is 50 or 100 feet give or take. While obstacles will degrade the signal, at close distance they will not render it useless. My wireless router has no problem with a few walls made of drywall. The laptop works through the house and on my neighbors front porch across the street.

Just My Take and I now see others have posted.

Ron

 

[Sceadwian]

Line of site from antenna to antenna or from an optical perspective? Line of site to the folks that don't understand it is system specific. EVERYTHING that transmits and receives energy is line of site relative to the transmission method. Mind you that the bulk majority of people that visit this site will see 'line of site' and attribute human vision to it. The antenna's do not need to be in the visual spectrum able to see each other, just in the spectrum they're transmitting in.

ronsimpsons post is so undetailed that it will from the perspective of someone that doesn't know any better be interpreted as it's opposite meaning.

I would like to see direct proof that a single tree can block a wifi signal by itself otherwise environmentally unencumbered.