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Author Topic: Wooden wall 5GHz  (Read 798 times)

Weaver

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Wooden wall 5GHz
« on: November 04, 2019, 11:49:52 AM »

I am getting problems with wireless LAN signal strength even though I am close to my WAP. Iím using 5GHz and WAP reports 0% signal strength when talking to my ipad; I am in my bed, as always, and the WAP is outside the bedroom, on the landing, about 7m away from my bed, with a wooden wall in the way of line of sight. There is a doorway between the landing and bedroom right next to the WAP but the WAP is off to one side so that there is no straight line of sight and the WAPís signal would have to be reflected off something or diffract around the edges of the doorway to get through the doorway to the receiving station. Not such a good chance of diffraction at a wavelength  of 0.06m for 5GHz - we need a longer wavelength. And nothing to reflect off, as far as I can see. So I think that the placement where the WAP is not visible through the doorway is a bad problem. It seems that 5GHz really doesnít like going straight through the wood? Is that the general experience?

If the WAP could be moved so that it shone through the doorway then that would help me in bed but then make a new problem elsewhere in the bedroom - for someone sitting in a large chair in the bedroom bay window to the east the signal would - I assume from the geometry - get rather worse. Iíll look into the feasibility of moving it but I donít think itís a solution. I would prefer to move it into the bedroom itself and then deploy another WAP outside on the landing I think - to replace the existing one.

What do you think?

The problem then is how to get stiff CAT-over-the-top ethernet cable into the bedroom through from the landing. Canít run it through the door unless we use a cable bridge and then presumably would not be able to shut the door, but I can at least look into it. Other option might be to drill a hole through the (wooden) wall and run straight into the bedroom. Could use POE if I can find my POE injectors - Janet has hopefully Ďfiledí them somewhere - but in any case mains for the WAP is available in the bedroom.

The ZyXEL WAPs are not mean for ceiling mount really and have long antennae that stick out, so would be unsightly in the ceiling and perhaps part your hair too when going past. Could place them in plenty of other places. The Cisco WAPs - which I have yet to evaluate - are ceiling mount friendly, if used with POE, obviously, so that going in over the doorway might be an option, but again a bit unsightly. Going through the wall by the side of the door looks like a bit of a nightmare because of the geometry on the outside, where there is a stairway in between the existing WAP and the bedroom wall.

One other thing that concerns me. Due to my use of very stiff thick ott ethernet cable, I have to be very careful not to damage the cable during installation or to bend it round too small a radius at any time. When it goes through a wall, how do I get a large enough radius of curvature ? In order that the cable not be coming out of the wall at right angles and then needing somehow to be bent through 90 degrees, whatís the best thing to do? Go in at a large angle on the whack, not at right angles to the wall? Would that be a solution?

Also, would going in over the ceiling in the roof space be feasible? Would be very neat with appropriate ceiling mount WAPs ? unless they are only meant for office ceilings, with tiles and a space above?
« Last Edit: November 04, 2019, 12:11:38 PM by Weaver »
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aesmith

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Re: Wooden wall 5GHz
« Reply #1 on: November 04, 2019, 02:04:03 PM »

Minimum bend radius is generally taken as four times the cable overall diameter as a rough rule of thumb.   If the installation is awkward I would consider using Cat 5e flying leads rather than fixed cabling and data outlets.  You can use a brush plate or similar to cover the exit point, and the hole in the wall only needs to be big enough to pass the connector through.  In terms of tidiness the slack stays in the roof space or wall cavity, and only enough cable drawn out to reach the end device.

Having said all that I can't help thinking there's something wrong with the wireless if you can't get cover 7m away.
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burakkucat

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Re: Wooden wall 5GHz
« Reply #2 on: November 04, 2019, 05:28:06 PM »

. . . I can't help thinking there's something wrong with the wireless if you can't get cover 7m away.

That was exactly my thought. A wooden wall should not be a significant impediment to the signal.
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aesmith

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Re: Wooden wall 5GHz
« Reply #3 on: November 04, 2019, 06:52:07 PM »

Just for reference I can get a reliable connection between device in the kitchen, and our Zyxel 8934 in the living room.  That's a distance of around 10m and passing through four lath and plaster walls, a stairwell and a storeroom full of "stuff".
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Weaver

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Re: Wooden wall 5GHz
« Reply #4 on: November 04, 2019, 10:25:54 PM »

I take your point about the signal strength. The reporting is very confusing as the WAPís stations report says 300Mbps tx; 60 Mbps rx; signal strength 0% for my iPad for example. So perhaps the antennae are loose or the WAP is getting past it. I can swap the WAP out and see if that makes a difference. Iíd much rather do nothing at all.

I have had one or two occasions when I have had complaints about signal strength or practical short-term connectivity problems. I have out these down to iPadOS 13 bugs though and every time I have had such a rare event, a reboot fixes it and a ping reveals there actually is connectivity still. Also speed tests give superb results although you would think that signal strength 0% might have a noticeable effect.

The WAP is eight years old so it is time to review it. I have a spare one already and there is now th chance of getting the Cisco WAPs going if I can ever get round to putting them in the post.
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sevenlayermuddle

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Re: Wooden wall 5GHz
« Reply #5 on: November 04, 2019, 10:53:22 PM »

@Weaver, do you need to use 5GHz?   In most circumstances where signal attenuation is Ďthe problemí, 2.4 GHz will fare better.
« Last Edit: November 04, 2019, 10:56:13 PM by sevenlayermuddle »
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aesmith

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Re: Wooden wall 5GHz
« Reply #6 on: November 05, 2019, 07:56:48 AM »

I don't know if there's an equivalent for Ipad, but I have a useful application on the Android tablet called "Wifi Analyser".   That shows all the SSIDs detected, and their various signal strengths, channels etc with signal strength's given in dBm.
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Weaver

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Re: Wooden wall 5GHz
« Reply #7 on: November 10, 2019, 05:29:10 AM »

@7lm Iíve been thinking about that. 2.4GHz is available downstairs where channel 1 is bonded to be double width 44MHz with channel 6, so only channel 11 is free, unless I can get channel 14 to work and use four-slot allocation rather than three slot. I am upstairs in my bedroom where the downstairs 2.4GHz WAP might well be audible, I havenít checked. I could reduce some of the 2.4GHz channels to be only 22 MHz wide so I could take a single or double width slot myself upstairs too. Itís all a bit complicated.

I chose to give myself a 5GHz 40MHz wide channel that no one else uses on radio 2 of the upstairs WAP. (Each WAP has 2 radios and each can be either 2.4GHz of 5GHz independently; theyíre not fixed to be in either one band or another.) In the case of the upstairs WAP I have both radios in 5GHz, one being my private, single-user BSS.

The questions I have:

1. Does this mean that I have some duff kit then, as the WAP ought to be able to cope with 5GHz through a simple wooden wall? I can swap out the WAP if I can get Janet to find the spare.

If 5GHz should be good enough then I donít need to be thinking about reallocating things in 2.4GHz, a precious resource that is set up just right now and whose allocation I donít really want to alter and mess up.

2. Does anyone here have 5GHz going through a wall?

3. If more modern kit that is 802.11ac wave 2 with beam forming might help a lot, thereís still the question of tx from the stations to the WAP through the wall. The Ciscoís might not be relevant as the iPad tx could still be the limiting factor.

4. Is it a bad thing to use up all of the 2.4GHz channels leaving absolutely no free space? Currently I have intentionally left 1 slot out of three free in 2.4GHz thinking that Bluetooth and such junk may then be intelligent enough to prefer that free channel rather than interfering with 802.11, either in a civilised or uncivilised way; I donít really understand the details if Bluetooth coexistence or lack of it.

5. I donít understand why the numbers Iím seeing from the WAP are what they are: why 300MHz d/s and 0% signal strength - shouldnít it be going to a slower speed mode if struggling that much? Or am I just not understanding ?

The ping time to the WAP itself is an amazing 8ms. Is that something to do with handling the crypto, because itís an ancient ten year old 400MHz MIPS64 (iirc) processor in the WAP? Canít imagine it is because itís only a ping, not much data to handle. Or more likely does such a ping time mean a load of L2 retxs because of continual errors?
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sevenlayermuddle

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Re: Wooden wall 5GHz
« Reply #8 on: November 10, 2019, 09:14:24 AM »

How are you measuring the ping times?

I have just installed a 'ping' App on my iPad, and it also reports pings around 8mS.   But when I sit at my iMac, unplug the lan cable and activate Wireless, I see pings around 2mS to the same AP/Router. 

I am therefor suspecting that, in my case, the surprisingly long 8mS pings are attributable to delays in the iOS application scheduling.  I am trying to figure out if I know (or should know) of any reasons why it would be hard, in an iOS App, to implement 'ping' with sub-microsecond resolution.  My hunch is that it would indeed be challenging, but it is either too early in the morning, or too late in my life, to formulate any specific theories.  I think some iOS devices these days have 120Hz refresh, which means the screen gets repainted ever 8mS, which might, just maybe, be relevant.
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d2d4j

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Re: Wooden wall 5GHz
« Reply #9 on: November 10, 2019, 09:34:33 AM »

Hi

@7lm - I just tried pinging one of our ac Wi-Fi and it shows as 3.2ms - see picture

This was completed from an iPhone 5 running very latest iOS (yes iPhone 5s still supports updates)

Interestingly another ping app showed 23ms so thinking it is down to how the app interacts

Many thanks

John

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Ronski

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Re: Wooden wall 5GHz
« Reply #10 on: November 10, 2019, 09:56:40 AM »

I have my main access point in the loft, the other one doesn't have 5Ghz enabled.

Sat in bed my Android Tablet reports a 5Ghz link speed of 32Mbps, my Huawei Mate 20 Pro reports 234Mbps, both describe the signal strength as fair.

If I draw a dead straight line from the AP to my devices position, the signal passes through 300mm of insulation, a12.5mm foil backed plasterboard ceiling, then a wall which has 20mm thick marble tiles on it, aqua panel wall board, sound insulation, studwork, plywood (19mm IIRC) then 12.5mm plaster board. Our bed is directly against that wall.

I tend to use the 2.4Ghz network as its perfectly adequate for what we use or wireless devices for.
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sevenlayermuddle

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Re: Wooden wall 5GHz
« Reply #11 on: November 10, 2019, 10:08:17 AM »

Iíve tried a couple of iOS ping Apps.   Running continuously, each shows the occasional ping of 2 or 3mS (and occasionally much longer too) but vast majority are around 8mS.  Proximity to AP makes no great difference, though Iíve not tried walking away out of range as it is raining,.

From command line on iMac to same AP/Router (billion 7800), itís consistently around 2mS over Wifi, less than 1mS wired.  The iMac results seem credible to me.
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aesmith

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Re: Wooden wall 5GHz
« Reply #12 on: November 10, 2019, 05:30:59 PM »

@7lm Iíve been thinking about that. 2.4GHz is available downstairs where channel 1 is bonded to be double width 44MHz with channel 6, so only channel 11 is free, unless I can get channel 14 to work and use four-slot allocation rather than three slot. I am upstairs in my bedroom where the downstairs 2.4GHz WAP might well be audible, I havenít checked. I could reduce some of the 2.4GHz channels to be only 22 MHz wide so I could take a single or double width slot myself upstairs too. Itís all a bit complicated.
I'm pretty sure we generally leave everything on auto and let the devices choose channels.  I can definitely remember one case with quite high AP density where manually setting channels backed us into a corner with poor coverage reported in various areas, resetting everything to auto sorted that out.  That was Cisco controller based APs so has the advantage that the controller sees everything.

At home I have our main AP/Router (Mikrotik),  a TP-Link power line adapter (2.4 only), and the Zyxel DSL router.  All on auto and apparently coexisting.   Current channels they've chosen are ..
2.4GHz - Mikrotik 7+11 40MHz,  TP-Link 6+10 40MHz,  Zyxel 8 22MHz
5GHz = Mikrotik36 80MHz, Zyxel 60 80Mz

Revisiting my test earlier I have to retract a little.  When testing between kitchen and living room (four walls, junk room, stairwell etc) I think my device was jumping only 2.4GHz.  Disabling 2.4 I can get a reliable signal on 5GHz in the bathroom (three wall, junk room) but not the kitchen.
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