WIFI repeater / bridge - Page 1
Forum section: electronics / general

author: soldar
author_rank: Super Contributor
timestamp: October 06, 2019, 07:06:03 pm
content: In my second home I connect to my neighbor's WIFI (with his permission, obviously). His house is four up the street from mine, on the same side of the street. Up until now it has been more or less working. If they are using the WIFI a lot themselves then my signal is not strong enough and they get all the bandwidth. So it works well for everybody. He never has the problem of me slowing them down.But my connection has been getting worse over the months and now there are times of day when I can hardly connect at all. Even at hours when there should be little or no traffic my connection is not reliable any more. I guess it might be from a couple new WIFIs that have popped up.He has placed his AP near the front of the house and I have also placed my client near the front but I suspect the signal is bouncing off from across the street because to go direct it would have to go through three masonry houses.I have given some thought to how to improve the connection. Any kind of cables are out for several reasons, the main one being his wife would not allow it.So I have thought of a WIFI repeater (bridge, whatever) across the street where it has a good view of both houses.Now, I have done this kind of thing in the past. I would take a WIFI client (e.g. WET54G) connect it via Ethernet to a WIFI access point (any old router would do) and I had a repeater.BUT the only way I can put this repeater across the street is to park my car there and put it in the car. I guess I could try the "client + AP" approach but I would prefer to find a simpler one single device solution. Part of that is that it will run off the car battery and I want to make it as simple as possible. Ideally just one device that I can unplug when I'm driving. (I would have to think about consumption because I sometimes do not move the car in over a week.)So, I have started looking into WIFI repeater/bridges or whatever they call them. Ideally I would like to use hardware that I have if at all possible. Also, my experience with WIFI antennas is that internal antennas are not worth a crap and only external antennas half work.I have read some types of receivers halve the WIFI bandwidth because of the half duplex nature of WIFI. This is fine as I do not think it would be a problem.The problem is that I start looking into WDS, MESH, repeater, etc and I get confused and lost.It seems they all work differently. Some will just repeat packets to and fro so you are really connecting through the repeater to the "original" AP. Dunno. I guess I could do that but it is not what I am used to doing so I think I would like to avoid this. I think I would like to have the same configuration as I am familiar with two separate devices: as a client log into the base AP and separately open a different WIFI AP with different SSID and password. It can be on the same subnet as the primary AP or it can be on a different subnet.I would log into the AP side and from there configure the client side to connect into the "primary" AP. That's the idea. Now comes the question of how to best implement it.I have a 3Com Office connect WL-542 ADSL router that I use as switch and WIFI AP. It has a configuration page that says it can be configured as WDS and allows scanning for networks but I have no idea how this works. The more I read the more confused I am. It does not look like it does what I want but I am not clear what it does do so I wonder if maybe it would do it.The Wikipedia page on WDS is confusing to me.https://en.wikipedia.org/wiki/Wireless_distribution_systemI have a TP-Link WR841N(TPD) Ver 9.0 router on which I installed Open-WRTand it seems Open-WRT has this capability but I would have to install some additional firmware and it seems the hardware was already limited so probably no more storage.Reading this pagehttps://openwrt.org/docs/guide-user/network/wifi/relay_configurationit seems it is a packet repeater so I would be on the same LAN which I could do but would prefer to avoid if possible.Another Open-WRT page:https://openwrt.org/docs/guide-user/network/wifi/mesh/startI have some devices with internal antennas which I seem to remember can be configured as repeater or bridge. I guess I could give them a try but, as I say, my experience with internal antennas is not good.Another aspect is power supply. Ideally one single device at 12 Volts to be plugged into the lighter. Right now I have at hand a WEP54G and a router/AP both at 5 Volts. I could mount them both on a board and find a step-down adapter. Not greatly difficult to get started but before I do anything I'd like to hear ideas and understand the issue better.

author: Whales
author_rank: Super Contributor
timestamp: October 06, 2019, 11:51:12 pm
content: Yes wifi can be 'repeated' in a lot of different ways. Some of them are actually really proprietary too.QuoteYou would want them on different subnets, to make the NAT simpler. You will have to use a NAT unless both ends support one of the proprietary wireless bridging protocols; or if you go for one of the more complex setups ("4-something"? I think the off-the-shelf-all-in-one repeaters might do this).I didn't go into a great amount of detail about in mylong-range wifiarticle, but this was my setup:Device 1 (running openwrt):Connected to a distant wireless access point, normal client-style connection.Mounted up a stick on the side of the house (with a directional antenna too)Setup to NAT between wifi (WAN) and ethernet (LAN)Running a dhcp server on the LAN side (dnsmasq)Device 1 and 2 were connected by a long ethernet cable.Device 2 (crappy off-the-shelf wifi router that I found in a bin and doesn't support openwrt):Mounted inside the houseActing as a wifi AP for us to useDHCP server disabled (only some let you do this, I telnetted in and manually killed the process)

author: Whales
author_rank: Super Contributor
timestamp: October 06, 2019, 11:53:14 pm
content: Oh and everything with the word "mesh" in the wireless world: assume it's heavily experimental. Pretty much only "client" and "station" modes of operation are reliable across most (not all!) devices.The most standardised mesh-ish thing is "ad-hoc" mode. Everything other than ad-hoc is not part of the standards as far as I am aware.

author: soldar
author_rank: Super Contributor
timestamp: October 07, 2019, 10:59:22 am
content: Quote from: Whales on October 06, 2019, 11:51:12 pmThanks. That setup is pretty much what I have now and what I have done quite a few times in the past. The only difference is that I use a normal USB or Ethernet WIFI client rather than a home-made antenna. I might experiment with helical antennas but in an urban setting the problem is not weak signals but a lot of interference from other WIFI.I have done some tests and reception from across the street is great. I can use my iPad without problem and the iPad, with its internal antenna, does need a good quality signal. I have no doubt that a relay/repeater would work perfectly. The question is the physical build. I guess I could start with assembling on a board a client, AP, power supplies, etc. It would be bulky and inconvenient but would give me a good start. The main hurdle right now is that the devices I would be using none are 12 V so I would have to provide step-down regulators.I could use a larger board and separate client and AP so they interfere as little as possible with each other. Maybe provide some shields or reflectors as shown in the drawing.Then later maybe try to use a single device.

author: OwO
author_rank: Super Contributor
timestamp: October 07, 2019, 12:08:33 pm
content: Use a SBC with two usb wifi cards. Set up hostapd on one of them and client on the other. Then use iptables to do NAT.

author: Whales
author_rank: Super Contributor
timestamp: October 08, 2019, 10:14:25 am
content: Quote from: soldar on October 07, 2019, 10:59:22 amRaised noise floor or lowered intended signal, both have a similar impact and similar solutions (to a certain degree -- all equipment has limits and interference isn't time-constant). A directional antenna will allow you to reject a lot of the interference.General disclaimer: make sure directional antennas are legal and ethical in your situation. Many countries require you lower power if you use them and using them wrong can cause issues for other people. If you're not comfortable with all of this then don't worry, stick to what you're doing.QuoteIt's always worth cracking them open to have a look. Many wireless routers have switchmodes on the input, it may be easy to check the ratings of the parts.Small stepdown modules are cheap (a few $ each) from the unusual greymarket culprits. I fuse mineQuoteAlways start with bulky and inconvenient. It's far more inconvenient to change a small design that has taken many hours to make but does not work.Also: if you worry what it looks like, then you're going to get an inferior solutionPlastic food container weatherproofing or none at all.QuoteYes. Also this lets you tinker more easily -- it took me quite a few changes of device (at both ends of my setup) until I settled with my final choices.QuoteWhat drawing?

author: soldar
author_rank: Super Contributor
timestamp: October 08, 2019, 10:11:03 pm
content: Whales, thank you so much for your detailed posts. I have also been reading with great interest your page about helix antennas and others of your website.Quote from: Whales on October 08, 2019, 10:14:25 amYes, I understand these issues. In the past I have also had good luck using reflectors behind the antennas as depicted in the diagram attached.Quote from: Whales on October 08, 2019, 10:14:25 amThis is Spain we're talking about. Laws and regulations here have no relevance except, maybe, as obscure curiosities. They are certainly not observed. I doubt anyone would know or care if a helicoid antenna is legal. this is total chaos here.Regarding the voltage of the PSUs, it is not worth looking into. Too much trouble.I spent quite a few hours with my first tests. I took a board and used bungee cord to secure WIFI client, Router, power supplies and a 12 V to 220 V ac converter. Quite a sight. I did some experiments but it was frustrating because of many little problems popping up. I did not achieve anything conclusive.The next day I thought I would re-examine the situation and experimented with placing the WIFi client in my front yard. While not perfect the results for now are good enough that I will probably go that way as it simplifies things a lot. The thing is that the adapter will be open in the weather so it will be Tupperware timeWith my projects I generally I end up with pretty satisfying results but they are the product of lots of time dedicated to experimenting and thinking. I think this is going to be one such case. The final solution will not look like anything special but will be the result of many hours of polishing.Quote from: Whales on October 08, 2019, 10:14:25 amSorry, my connection was so bad I gave up trying to upload it. I am uploading it now even though for now it is not what I am working on.For now, since the WIFI client is in my yard, I will be using Ethernet, at least while I experiment. I also have a mains power cable and I might later look into delivering power over the ethernet cable. That will be a second phase.

author: Whales
author_rank: Super Contributor
timestamp: October 09, 2019, 06:38:09 am
content: Quote from: soldar on October 08, 2019, 10:11:03 pmN.B. unless this is a really good quality unit, with proper filters, then it will probably kill the reception of any devices it is connected to. Many inverters skip the "necessary" filter stages because they cost money and most customers don't understand what happens when they are gone.Reflectors: parabolic reflectors can be useful, there is a whole subculture of using them with USB wifi dongles. It will be harder to use them for a whole router, unless you modify the antenna to be on the end of a lead. Keywords are "parabolic cookware wifi", here'sa site I used to look at.Interference and law: regardless of the local law, it's still a good idea to make sure you're not causing trouble for other people. Especially the neighbour lending you internet.Otherwise: good luck, hope you manage to get a reliable link

author: ogden
author_rank: Super Contributor
timestamp: October 09, 2019, 07:28:19 am
content: WIFI 2.4G is overcrowded. It is OK *only* for local wireless where WiFi of the neighbors does not matter due to strong signal. Trying to use 2.4G for outdoor point-point connections is pointless waste of time and resources, especially sharing same AP for local and far, weak signal clients . For point-point connections better use 5G frequencies and purpose-built hardware, something like this:https://mikrotik.com/product/RBSXTsq5nD. Ubiquiti is another brand of possible choice.

author: Jeroen3
author_rank: Super Contributor
timestamp: October 09, 2019, 07:34:14 am
content: The important bit is to not use the same channel as the uplink. Dual radio is required.This is easy in any relaxed dual band radio, you set wlan1 to station-bridge* mode and wlan2 to ap mode, bridge them and you're done!*station-pseudobridge for mikrotiks.

author: soldar
author_rank: Super Contributor
timestamp: October 09, 2019, 09:04:11 am
content: I think the degradation of the earlier connection might be a result of two or three new WIFIs appearing. I find it interesting that one of them is a device installed in the electric distribution transformer located across the street from me. It measures and computes power distribution and my take is that they are investigating electric power theft. If the total power indicated by that device as being delivered to the sector is more than what is being measured by home meters in that sector then power is "leaking". I don't know why it would need WIFi unless it is for someone to stop by periodically and collect data.http://circutor.com/enPart of the problem might be the AP jumping channels trying to find the one with least clutter. Every time the AP jumps to a new channel all connections have to be re-established. I think there might be several WIFIs jumping around the channels trying to find the best spot. I may try to find the best compromise and fix it to one channel.Quote from: Whales on October 09, 2019, 06:38:09 amDefinitely not "good quality". Just a very small and cheap unit. I did not think of this. Yeah, better stay away from this.Quote from: Whales on October 09, 2019, 06:38:09 amI have used them with good results. USB WIFI dongles with long antennas have worked best for me BUT you need a computer pretty close which prevents installing them at the end of the yard, way from the house. Ethernet WIFI clients are just OK, I have several Linksys WET54g, and they work OK but not as good as USB. As you say, making reflectors is also more complicated.For now I have placed an Ethernet WIFI client at the end of the yard and it is working reasonably well but it cannot stay like that. I will have to weatherproof it, as well as the cables, etc. I will probably look at using the ethernet cable for power supply.