View Full Version : wireless signal vs concrete floor

04-11-2011, 08:04 AM
Hi I have a networking question

I m looking at getting a NETGEAR DGND3700 WIRELESS-N DUAL BAND N600 GIGABIT ADSL2+ MODEM 4-PORT ROUTER for the upstairs part of my house but was also wanting to know if the wireless signal was able to go through a reinforced concrete floor to my basement where my wifes new office is going to be set up?

I was thinking of using NetGear powerline but emailed there support team and they told me that it wouldnt work due to the phase line splits into multiple power circuits at the distribution board.

Other thoughts were buying a Range Extender

So I thought I would come here to get some advice, any help would be very appreciated

04-11-2011, 08:17 AM
Is there a phone in her office ... wired or wireless ??

04-11-2011, 08:24 AM
You're probably going to largely be out of luck.

I'd try the Ethernet over Power adapters personally, unless you're *certain* that your home is wired up on different circuits?

04-11-2011, 09:34 AM
Any chance of running a cable down an outside wall? (Hard to get them in and out of the house, I know).

04-11-2011, 10:01 PM
If it was me I'd drill a hole through the concrete floor,tread a length of suitable cable and fit a RJ-45 wall plate socket at each end. If your wifes new office is being set up by professional trades people the cost will be relatively small and tax deductable and the connection will be more reliable and less prone to interferance from other wireless signals.

06-11-2011, 09:14 AM
I'm running wireless N network via a Netgear DGN2200 - I have good signal even after it passes through a concrete wall (breeze blocks). The router is right up against the wall AND next to a large aquarium (which are known to absorb signals).

I would say it it would work - depending on how much metal is in the floor (pipes, cable,fire proof foil, joist struts etc). However like others said your best bet would still be to run a hard line down through the floor.

What I used to test my network range was my cell phone - I walked around in and outside looking for dead spots in signal strength.

06-11-2011, 10:13 AM
Thanks for all the helpful advice, Disco_Dan cheers that really helps alot i might get a AP to act as a repeater and place it by the stairs leading down to the basement hopefully it can boost the signal to make it even stronger

07-11-2011, 08:43 PM
Other thoughts were buying a Range Extender

I wouldn't suggest buying anything until you do a site test. Can you borrow a WAP - even an older 802.11g would do as you know 802.11n will be better. Test the coverage with a laptop or use your SmartPhone if you have one (e.g. WiFi Analyzer on Android). Everything may work fine - you don't know until you try.

Alex B
07-11-2011, 08:57 PM

We have a few of these at work in a semi high rise, (floors are thick steel/concrete mesh) and we see wifi the next story down just fine.

Billy T
07-11-2011, 09:20 PM
Unless still green or full of wire mesh, concrete is not a particularly effective barrier to normal RF signals, however GHz-frequency signals do suffer greater losses. In many cases this can be overcome to a worthwhile extent by adding to the effective radiating efficiency of the antenna.

All it takes to do this is several metres of 13 x 0.12mm PVC insulated tinned hookup wire ($5.90 for a 13 metre roll at Jaycar, choose your colour). Wind about 15-20 turns around the antenna of your router and lay the rest of the wire antenna along the floor by the wall. If you have carpet you can tuck it out of sight. In most cases it will make patchy signals much stronger. If it runs in more than one axis, that is all to the good.

I mentioned a while back that a similar arrangement increased the range of a small FM Band transmitter from 10 or so metres to a few hundred metres, with pockets of reception nearly a Km away. Analog signals are much harder to extend than digital because there is no error correction and dropouts or phasing conflicts sound awful. Passive range extenders for similar GHz frequencies and functions are sold on TM and can extend a 50 metre range to several Km so the theory and principles are good.

It should work in most situations, but if not in your case, you are only a few bucks down and had the fun of trying. You don't want to boost your signal too much though, you never know who might be listening.


Billy 8-{)

08-11-2011, 01:01 PM
The Wireless Basics page on the Gowifi link above is a great read. (thanks AlexB)


Didnt realise even plasterboard has a 3db attenuation. Thats fairly significant.

Ive found a few sites just dont have reliable wifi, no matter what I'd try (within reason)
I havnt had much luck with repeaters, active (powered) boosters etc.
Other sites just work perfectly, where you think it wouldnt , eg up 3 floors or with access point in a foil insulated garage

Just a matter of trying it out & seeing if it actually works.

10-11-2011, 08:08 PM
Thanks for all your help and advice guys i went with a EnGenius ECB9500 802.11b/g/n Wireless Multifunction Access Point placed it up high by the stairs and it worked a treat

so again cheers guys and thanks

10-11-2011, 09:25 PM
Good result. My son did a similar placement at the head of the stairs and it made a difference.