Extending WiFi antennas from your router

[barnabas1969]

My wireless router is in a closet. It has two antennas. I'm interested in extending the antennas and mounting them on the ceiling of my house so that the antennas are not in a closet, which reduces the signal strength from them.

I've found some 6 meter extension cables (and RP-SMA to RP-TNC adapters) that will work with my router/antennas. This length will give me some flexibility in antenna placement, and will allow me to run the cable through the attic. The cables have a panel-mount connector at the antenna end.

I plan to experiment by hanging the antennas temporarily in various locations around the house to determine the best placement before mounting them permanently.

Does anyone here have experience using such a long cable (6M) with 802.11g?

Thanks in advance for your input.

[barnabas1969]

I'll add that I understand that the longer cables will attenuate (reduce) the signal. However, since I've never done this with 802.11g, I don't know how much attenuation to expect with 6m cables. Obviously, putting the antennas in line-of-sight from my devices will be better than connecting the antennas directly to the modem in the closet, but I'd like to know how much the 6m cables will affect the transmit/receive signal strength for 802.11g.

Thanks.

[olyteddy]

Lots of coax loss charts out there on the web. You need to know the type of Coax, Length (6 meters) and Frequency (2410 MHz) and look it up.

[barnabas1969]

Well, I got my cables and adapters. I've temporarily hung my antennas from various locations around the house to determine the best placement. The router has two antennas, and I've extended both of them. It is running DD-WRT, and the antennas are set to "auto", which to the best of my knowledge means that it will use antenna diversity to automatically select the best antenna.

I tried placing both antennas in the same places (side by side, like they are when attached to the back of the router), and I've also tried separating them by placing them as far apart as possible (12 meters). I get better overall coverage by placing the antennas at opposite ends of the house.

I'm wondering how quickly a router can switch between antennas. Let's say that two people are using two different wireless devices at opposite ends of the house. Can the router switch rapidly between the two antennas to provide reliable service to both users?

[barnabas1969]

I can get speeds (from speedtest.net) over WiFi of about 15Mbps down and 2.something up (I get 27down and 2.something up with a wired connection).

I tried a test with two laptops at opposite ends of the house, and the antennas as far apart as possible so that each laptop gets the best signal from separate antennas. My house is built like a bomb shelter (even the INTERIOR walls are concrete with wire lath!), with windows that have some type of metal in the glass to keep radiant heat from the sun to a minimum. As you can imagine, this is not the best scenario for wireless signals.

I called my wife on her cell phone so that we could both start the test at the same time. I got 8.something and she got 7.something down, and we each got 1.something up. So, that adds up to the 15.something that I get download over WiFi, and it maxes out the upload speed from my ISP.

I'm very impressed. I never imagined that the router would be able to handle two devices on separate antennas at the same time with such performance.

Now, just to be clear... if I put both antennas in the kitchen, I get almost no signal in the master bedroom (which is where my laptop was)... so I know that my laptop was connecting to the antenna that I placed at the end of the hallway. She was sitting in the living room, and based on the signal strength on her laptop, she was connecting to the antenna in the kitchen. Both worked equally well.

I think I know where I'm going to mount my antennas now. I'll be working from home tomorrow, so I'll leave the antennas in their present locations so that I can test their stability during an 8-hour workday using VPN over wireless. If all goes well tomorrow, I'll be permanently mounting my antennas next weekend. Right now, I'm using the antennas that came with the WRT-54GL router. I've ordered a pair of omni-directional antennas with higher gain (5.5dBi vs 2.0 dBi), and they should be here by the weekend too.

Right now, even with the lower-gain antennas, I get coverage in all areas of my house, and even out into the back yard all the way to the far end of the pool deck. The signal is very weak out there at the edge of the pool deck, so that's why I've ordered higher gain antennas.

[barnabas1969]

I got the higher gain antennas today. My laptop reports 40% signal strength all the way to my back fence now. At that distance (approx 12-13 meters from the back of the house), I get a pretty consistent 5Mbps download speed on the laptop when I'm standing out by the fence.

My phone doesn't get as good of a signal though. It gets 1-2 Mbps download speed by the fence. I assume that's because the antenna in the phone isn't as good as the one in the laptop. It's still pretty respectable considering that I got NO signal on my phone ANYWHERE in my back yard before I made these changes. I couldn't even stand right by my back door and get signal with my phone before!

I'd like to improve it even more. I did more reading on cables and their attenuation at 2.4GHz. The cheapie cables I bought for $5 each (6 meter cables) are RG174. It turns out that RG58/U cables attenuate the signal about 1/2 as much as RG174 (each 3dB of attenuation cuts the signal 1/2). I found RG58/U cables for about $15 each. I ordered them today. I should have them by next weekend... and that's perfect because my son will be here by then (he can crawl through the attic!).

[holidayboy]

Nice topic, I need to experiment with my cheap ass 'N' router, see if I can get some back garden WiFi going on next summer.

[barnabas1969]

Nice topic, I need to experiment with my cheap butt 'N' router, see if I can get some back garden WiFi going on next summer.

Thanks. I was hoping that it would help someone. I've learned a lot. For instance, the higher the gain of an antenna... the more directional the antenna is. So, an omni-directional antenna with a higher gain will have higher gain in the plane that is perpendicular to the antenna (a vertically oriented antenna has a horizontal plane)... but that means that it directs less energy parallel to the antenna. I've read that you can stand directly under a 15dBi omni-directional antenna, and you will receive a very weak signal from it. But... if you stand beside it... you will get a strong signal.

Also, I never realized how much a coax cable will attenuate a signal. For instance, a 100ft RG174 cable will attenuate a 900MHz signal 20.2dB, while a 100ft RG58/U cable will attenuate the same signal, at the same length, by only 12.8dB. That's a difference of 7.4dB. Since the signal doubles (or halves) every 3dB, that means that a 100ft RG58/U cable will deliver a 900MHz signal that is more than four times as strong as the same length RG174 cable! The difference gets even greater as frequency increases.

So... since I'm using cables that are about 1/4 the length from the specs, and running at 2.4GHz (as opposed to 900MHz in the specs), I expect to achieve approximately a 50-100% increase in signal strength by using the RG58/U cable instead of RG174.

It will be interesting to see what happens!

My wife and kids think I'm nuts, by the way. I have antennas hanging from the ceiling, suspended by string that is stapled to the ceiling right now. The cables are taped to the walls to prevent anyone from tripping on them.

[staknhalo]

My wife and kids think I'm nuts

I have antennas hanging from the ceiling, suspended by string that is stapled to the ceiling

cables are taped to the walls

[barnabas1969]

And?

[staknhalo]

I picture you're house looking like jumanji but with technology

[barnabas1969]

No, it's not that bad. I have one cable coming from the wiring closet in the hallway that is taped to the wall above the bathroom door, and it goes to the middle of the kitchen ceiling, where the antenna is supported by a string that is stapled to the ceiling (because scotch tape wouldn't hold). There's another cable going the other direction down the hall with an antenna hanging from the ceiling at the end of the hall.

I didn't want to run wires through the attic and mount anything permanently until I found the best locations for the antennas, and the best antennas and cables to use.

I'm pretty happy with the way I have it setup right now, but I'm waiting to get lower-loss cables before I put it in the attic.

Most people would probably not need to go to such lengths... but my house is uniquely constructed:

The exterior walls are more than 12" thick. If you were to cut through from the outside, you would encounter vinyl siding, foam insulation, 8" thick concrete block, stuff that looks like thin drywall (1' x 8' x 3/8", hung horizontally), and on that drywall is spread stuff that looks like stucco (about 1" thick)... with wire lath embedded in it, and then another 1/4" of plaster on top of that.

Then, my windows are all designed to block radiant heat from the sun... and the metal in the glass also blocks some of the RF signal.

My interior walls are all made from the same strange layering of thin drywall, stucco, wire lath, and plaster.

As you can imagine, I have trouble with RF signals inside my house... and even worse problems getting those signals out of my house. I thought about putting a wireless AP outside... but then I started thinking about positioning my antennas in a place where they will cover both inside and outside. My plan is to put the antenna in the kitchen right in front of the kitchen window so that it gives the best coverage outside.

So far, it works pretty well.

[staknhalo]

No, I understand how frustrating something like this can be. I've been following/lurking this thread for a while; seeing if I could pick up any tips should I need them in the future. Luckily my N WiFi network is acceptable (for now). I was mainly just having some fun with you there is all Hope it works well for a LONG time.

[barnabas1969]

I can give you one tip. On a PC with a wireless network card, open a command window and run the following command:

netsh wlan show networks mode=bssid

It will show you all the wireless networks in range, their signal strength, and channel number. It can help you select the channel that will give you the best results. Something I learned recently... in the USA, there are only three channels that don't overlap others. Those are channels 1, 6, and 11. To get the absolute best reception, you and your neighbors should select one of those three, and try to make sure that your closest neighbors are never on the same channel as you. Of course, that assumes that your neighbors are willing to coordinate this with you.

[staknhalo]

I can give you one tip. On a PC with a wireless network card, open a command window and run the following command:

netsh wlan show networks mode=bssid

It will show you all the wireless networks in range, their signal strength, and channel number. It can help you select the channel that will give you the best results. Something I learned recently... in the USA, there are only three channels that don't overlap others. Those are channels 1, 6, and 11. To get the absolute best reception, you and your neighbors should select one of those three, and try to make sure that your closest neighbors are never on the same channel as you. Of course, that assumes that your neighbors are willing to coordinate this with you.

Yeah, I've already done that. You would be horrified if you saw a network map of my area. As for coordinating with my neighbors, no one talks to anyone here aside from the occasional head nod. I blame the HOA for killing all our souls lol.

Good tip though for others who might not know that.

[barnabas1969]

When I stand out in my yard, I pickup 19 wireless networks. It's pretty amazing.

[milli260876]

Wouldn't this http://www.engadget.com/2012/12/05/d-li ... -extender/
Work ???
And be considerably less faffing about??

[barnabas1969]

Wouldn't this http://www.engadget.com/2012/12/05/d-li ... -extender/
Work ???
And be considerably less faffing about??

No. Wireless range extenders always decrease your wireless throughput by at least half. Plus, given the construction of my house, that little device (with no external antennas) has absolutely no hope of ever extending the signal outside the walls of my house (which was the main purpose of me doing this).

[milli260876]

Having read your previous are you a naughty boy like the guy on goodfellas and living in a nuclear bunker?? Lol...
(I doth jest)
I know little about wireless range extenders tbh just saw it on Engadget and remembered your post, I have no doubt however that you're right!
Good luck with the antenna re-placement!!!

[barnabas1969]

Having read your previous are you a naughty boy like the guy on goodfellas and living in a nuclear bunker?? Lol...
(I doth jest)
I know little about wireless range extenders tbh just saw it on Engadget and remembered your post, I have no doubt however that you're right!
Good luck with the antenna re-placement!!!

OK, you found me out. I'm going to have to kill you now. Either that, or I'll have to relocate and change my identity again... and bullets are much cheaper.

Just to explain about range extenders, they halve your throughput because 802.11 is half-duplex. Your wireless device (computer, phone, iPod, whatever) sends data to the range extender, then the extender sends it to the wireless access point (AP), which is usually built into your router. Then, the AP sends an acknowledgement back to the range extender, and the range extender forwards that to your device. All this relaying and waiting slows down your overall connection.