00:06.04 | Mike25226 | hmmmm... Do you think researching/making an amplifier would be a better option since, like you said, PCB antennas are fairly standard |
00:07.11 | whitequark | no |
00:07.26 | whitequark | these are commodity hardware |
00:09.48 | Mike25226 | Not sure I'm following. If the design is fairly standard... how else can you improve such an antenna, if not with some sort of amplifier |
00:14.26 | whitequark | what exactly do you want to achieve |
00:14.52 | Mike25226 | better range |
00:15.31 | Mike25226 | as well as good signal level |
00:18.13 | whitequark | and you want an omnidirectional antenna with an amplifier? |
00:19.30 | Mike25226 | yeah |
00:19.48 | whitequark | pointless |
00:19.52 | whitequark | and illegal, too |
00:20.51 | whitequark | pointless because signal drops off as 1/r^2 (for a more powerful transmitter), in addition to receiver picking up garbage on the same channel from afar (for a more sensitive receiver) |
00:21.40 | whitequark | you could a) use a directional antenna b) set up a network out of several routers |
00:24.14 | Mike25226 | Inverse square law? |
00:24.30 | whitequark | yes |
00:26.20 | DocScrutinizer05 | generally an antenna with good gain would help. Hardly feasible as PCB antenna though |
00:27.12 | DocScrutinizer05 | decen ground plane antenna has quite a bit of gain from 2D (omni)directional |
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00:28.34 | DocScrutinizer05 | however will fail when you want to go vertical between AP and client |
00:29.39 | DocScrutinizer05 | I.E. a ground plane antenna in attic is rather contraproductive for clients inhouse "under" the antenna |
00:30.22 | DocScrutinizer05 | use MIMO |
00:31.01 | DocScrutinizer05 | it basically acts like an adaptive virtual directional antenna |
00:31.36 | Mike25226 | hmmm |
00:31.50 | Mike25226 | MIMO is a multiple antenna design right? |
00:31.56 | DocScrutinizer05 | yes |
00:32.29 | DocScrutinizer05 | http://en.wikipedia.org/wiki/Mimo |
00:33.37 | DocScrutinizer05 | also see http://en.wikipedia.org/wiki/Smart_Antennas |
00:37.18 | Mike25226 | Wouldn't a wireless card have to support it? I'm guessing it's not as simple as MAIN--= , AUX--= , = is 2 antennas |
00:37.38 | DocScrutinizer05 | yes, and many wireless cards _do_ support MIMO |
00:38.11 | whitequark | actually, you would frequently encounter cards with literally these ports |
00:38.13 | DocScrutinizer05 | and it is like they have 2 antenna connectors |
00:38.14 | whitequark | my latop has one |
00:39.44 | DocScrutinizer05 | recently I've seen APs with even 3 or 4 antennas |
00:39.54 | Mike25226 | http://sishardware.com/imgs/a/a/l/o/a/intel_7260ngw_m___2_ngff_wireless___ac_card_867mbps_802___11ac_bt4___0_1_lgw.jpg |
00:40.16 | DocScrutinizer05 | :nod: |
00:41.06 | DocScrutinizer05 | unclear if that's one antenna for 2.4 and one for 5, or MIMO-2 with 2 multiband antenna connectors |
00:41.51 | DocScrutinizer05 | often it's even configurable in vard's registers |
00:41.55 | DocScrutinizer05 | card's* |
00:42.08 | whitequark | I think 2.4 and 5 usually use the same antenna |
00:42.20 | Mike25226 | there is only one PCB antenna and both MAIN and AUX go to it |
00:42.21 | DocScrutinizer05 | usually, but not generally |
00:42.22 | whitequark | read some appnotes, they say it's good enough |
00:44.11 | DocScrutinizer05 | http://www.intel.com/content/dam/www/public/us/en/documents/product-briefs/dual-band-wireless-ac-7260-bluetooth-brief.pdf |
00:46.45 | DocScrutinizer05 | 2x2 |
00:47.12 | DocScrutinizer05 | suggests MIMO |
00:48.33 | DocScrutinizer05 | http://www.ebay.co.uk/itm/Genuine-Intel-Dual-Band-7260NGW-AN-WiFi-module-802-11abgn-2x2-MIMO-NGFF-M-2-/251849854651 >>Genuine Intel Dual Band 7260NGW AN WiFi module 802.11abgn 2x2 MIMO NGFF M.2<< |
00:49.00 | Mike25226 | interesting.... |
00:49.10 | Mike25226 | my laptop only uses 1 |
00:54.23 | Mike25226 | watching a disassembly video to verify |
00:55.09 | whitequark | crack it oopen |
00:58.49 | DocScrutinizer05 | wMIMO only makes sense with multiple physically distinct antennas. When your laptop only has one, it can't do MIMO |
00:59.00 | DocScrutinizer05 | -w |
00:59.55 | DocScrutinizer05 | conecting both antenna jacks of a mimo card to same antenna is contraproductive |
01:00.22 | Mike25226 | I've opened it before, and was 90% certain it only had one (twice actually). But I always feel the need to assure myself when i have the smallest bit of doubt. Guess you could say I lack confidence |
01:01.31 | Mike25226 | only has one |
01:01.45 | DocScrutinizer05 | which btw is the reason to call one "main" and one "aux". The "aux" is the one to leave unconnected when only one antenna is used |
01:02.36 | Mike25226 | Can a PCB antenna act as 2? |
01:02.46 | DocScrutinizer05 | the card will (either automatically or by config) shut down the "aux" antenna and use only one |
01:02.59 | Mike25226 | I imagine that would cause issues being that close |
01:03.02 | DocScrutinizer05 | no, no antenna can act "as 2" |
01:03.40 | Mike25226 | well, with a PCB... couldn't it be done? |
01:03.49 | DocScrutinizer05 | sorry? |
01:03.56 | Mike25226 | just tracing on back and front of PCB |
01:04.09 | DocScrutinizer05 | that's two antennas, not one |
01:04.55 | DocScrutinizer05 | however you must keep the antenna area clear of all conducting objects and traces, also of a second antenna |
01:05.28 | DocScrutinizer05 | IOW one antenna per dedicated area |
01:05.30 | Mike25226 | This image as an example: http://www.sequoia.co.uk/images/product/png/3364.png so the front could be lets say antenna 1, and back be antenna 2? |
01:06.05 | DocScrutinizer05 | this is one antenna in that picture |
01:06.30 | DocScrutinizer05 | the bottom side of the PCB MUST kept clear of *all* traces and conducting objects |
01:06.41 | Mike25226 | ahhh, gotcha |
01:07.20 | DocScrutinizer05 | of course you can have two of those on one PCB, with a small distance between them |
01:07.26 | Mike25226 | so that confirms that my laptop is only using one antenna, even though both main and aux connect to it |
01:07.45 | Mike25226 | you mean side by side? |
01:08.15 | DocScrutinizer05 | I guess that's pretty wrong a thing to do. Unless the data sheet of the card *explicitly* states to do so |
01:08.24 | DocScrutinizer05 | yes, side by side |
01:09.40 | DocScrutinizer05 | ideally in more than 1/2 the length of antenna as distance between them |
01:09.52 | Mike25226 | hmmm, guess I need to take a closer look. Since it would be pointless to have aux connected if it isn't the case (side by side). |
01:10.22 | DocScrutinizer05 | you MUST NOT split antenna cables |
01:10.28 | DocScrutinizer05 | like Y-cable |
01:10.40 | DocScrutinizer05 | this is generally absolutely forbidden |
01:11.06 | DocScrutinizer05 | so when your laptop has two antenna connectors, it quite likely has two antennas |
01:14.44 | DocScrutinizer05 | unless some jackass retrofitted the WLAN DIY without having faintest clue |
01:19.09 | kristianpaul | wpwrak: had you had tiem for trying docker? |
01:25.47 | Mike25226 | Made this picture with 3 figures. Figure 1 is how my laptop is setup http://oi61.tinypic.com/402uw.jpg |
01:26.15 | Mike25226 | Figure 2 is what I am thinking I can do. Figure 3..... I doubt |
01:30.34 | DocScrutinizer05 | figure1 is BS, done by somebody with no clue about RF basics. Figure2 is the standard setup. Fig3 is obscure, no idea what it means |
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01:32.19 | DocScrutinizer05 | adamnt rule of RF: one connector, one cable, one antenna |
01:32.45 | DocScrutinizer05 | you cannot do Y-cables |
01:33.39 | Mike25226 | hmmm... then lenovo really messed up.... which might explain why my signal isn't better |
01:33.49 | DocScrutinizer05 | you could add a band splitter to attach two antennas (one 2.4, one 5GHz) to one antenna input. Which would indeed look like fig3 then |
01:35.51 | DocScrutinizer05 | ech of the "small PCB" in fig3 would need to be a band splitter then, basically a special filter that routes 2.4GHz signals to and from one antenna and 5GHz signal to and from the other |
01:36.34 | DocScrutinizer05 | and of course this only makes sense when the antennas are actually made for only one band and can't handle the other |
01:36.36 | Mike25226 | would that be better? (I could be wrong, but it would then use a different antenna when probing/scanning for networks while connected to a network) |
01:37.10 | DocScrutinizer05 | no, that's not exactly how it works |
01:37.56 | Mike25226 | do cards only probe when requested to do so? |
01:38.03 | DocScrutinizer05 | the "advantage" is that the antennas get the signal they can handle. |
01:38.36 | DocScrutinizer05 | for the antenna it's irrelevant if the card is "probing" or talking or listening |
01:43.39 | Mike25226 | Is proximity of the 2.4GHz and 5GHz antennas important? Should they be some what distanced? |
01:55.59 | DocScrutinizer05 | do you even have 2.4 and 5GHz antennas? |
01:57.38 | DocScrutinizer05 | look, I'm not looking forward to discussing all possible permutations of configuring a multiband MIMO system, with all the gotchas this introduces |
01:58.48 | DocScrutinizer05 | when your PC has ony one antenna, connect it to "main" and leave "aux" open. When it actually has 2 antennas, you connect one to "main" and one to "aux" |
01:59.45 | DocScrutinizer05 | antenna *design* is an art rather than a science. Some even say it's voodoo |
01:59.55 | Mike25226 | I plan to purchase 2 new antennas |
02:00.01 | Mike25226 | or make them myself for fun |
02:00.18 | DocScrutinizer05 | and where do you plan to place those? |
02:00.45 | DocScrutinizer05 | mind you, they need to stay away a few cm from *all* conductive materials |
02:01.05 | DocScrutinizer05 | even isolated ones |
02:01.40 | whitequark | my laptop somehow fares fine despite a solid aluminium lid |
02:01.53 | whitequark | with the antennas at the very bottom of the screen |
02:02.27 | DocScrutinizer05 | well, when you *know* what you're doing, you can even integrate the antenna into the aluminium case |
02:03.01 | DocScrutinizer05 | but then user MUST NOT "hold it wrong" X-P |
02:04.20 | DocScrutinizer05 | the joy of doing RF tests in freefield, without anything resembling sth annoying like a user's hand ;-) |
02:05.00 | DocScrutinizer05 | "the device works perfectly, unless a planet is near" |
02:07.44 | DocScrutinizer05 | on a more honest less funny comment: you _can_ design antennas so they work near conducting surfaces. Actually a groundplane is exactly such a design. But you need to know your RF voodoo for that |
02:08.30 | Mike25226 | I plan to place the antennas flat down on both sides of the keyboard |
02:09.07 | DocScrutinizer05 | I guess that's about the worst place for antennas you could possibly find in a laptop |
02:09.39 | Mike25226 | that's where lenovo placed the one antenna lol |
02:09.48 | DocScrutinizer05 | assuming the kbd has an alu or steel base, and below the antennas would be main PCB, right? |
02:09.56 | Mike25226 | screen casing is metal |
02:10.04 | DocScrutinizer05 | see above |
02:10.16 | DocScrutinizer05 | on a more honest less funny comment: you _can_ design antennas so they work near conducting surfaces. Actually a groundplane is exactly such a design. But you need to know your RF voodoo for that |
02:11.23 | DocScrutinizer05 | sorry there's no simple answer to your problem |
02:12.55 | DocScrutinizer05 | odds are whatever you implement DIY in good failth will be inferior than what lenovo implemented |
02:14.40 | DocScrutinizer05 | so all I can recommend is: get the original service manual for your laptop and check what the manufacturer says how antenna is placed and built and how it shall get connected |
02:16.16 | DocScrutinizer05 | compare to what you got, and fix any weird "improvements" somebody might have applied (is this a laptop you bought used? was the WLAN card retrofitted by a cheap cheesy repair shop?) |
02:16.31 | Mike25226 | well, like I said, they use one antenna (or single small PCB). It is oriented horizontally (flat) to the right of the keyboard |
02:17.16 | Mike25226 | Whole body is aluminum except the surface with touchpad and keyboard |
02:17.39 | DocScrutinizer05 | that's all pretty fine but not sufficient info for me to recommend anything better than I already did |
02:19.02 | DocScrutinizer05 | "there's a small PCB and two cables come from that" is no info an EE can use to give any recommendations |
02:20.38 | DocScrutinizer05 | for all I know the "small PCB" might even have TWO antennas on it |
02:21.08 | DocScrutinizer05 | impossible to tell from the available info |
02:22.18 | DocScrutinizer05 | and "to the right of the keyboard" is not identical to what I understood when you said "flat down on both sides of the keyboard" |
02:23.27 | DocScrutinizer05 | I understood that as "under the kbd" not as "to the right/left of the kbd" |
02:23.59 | Mike25226 | Guess I'll just experiment and test. First like my figure 2 diagram, and then figure 3 after I do some research, using splitters like you said (for fig 3), |
02:24.19 | Mike25226 | it's to the right of the kbd |
02:24.28 | Mike25226 | not under the kbd |
02:25.09 | DocScrutinizer05 | figure3 would only make sense when you had dedicated singleband antennas. Why would you want to do that? it's an inferior solution to a multiband antenna |
02:25.11 | Mike25226 | Btw, thanks for your help. Really appreciate it, and I am learning some things I did not know before |
02:26.53 | DocScrutinizer05 | and excuse when I'm wrong here, but to me it seems you didn't understand what's a band splitter |
02:27.29 | DocScrutinizer05 | so your "small PCB" in fig3 is pretty unspecific |
02:27.31 | Mike25226 | Oh, I was under the impression it was advantageous to have them separated |
02:27.47 | DocScrutinizer05 | no it isn't |
02:28.21 | DocScrutinizer05 | sorry afk, busy |
02:28.33 | Mike25226 | k, thanks again for the help |
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03:11.39 | DocScrutinizer05 | he's gone, nevertheless prolly the term "band splitter" isn't exactly to the point, rather "frequency-separating filter" or "crossover" |
03:32.55 | DocScrutinizer05 | or diplexer |
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06:32.09 | wpwrak | kristianpaul: hmm no, didn't need to make any mini-VMs yet :) |
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07:22.17 | ahmed89_ | can you tell me whice psu is better ? this http://i.imgur.com/ntIyCsC.jpg or http://i.imgur.com/RSnEbXM.jpg |
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07:40.37 | ahmed89_ | m |
07:41.09 | ahmed89_ | can you tell me whice psu is better ? this http://i.imgur.com/ntIyCsC.jpg or http://i.imgur.com/RSnEbXM.jpg |
07:52.24 | eintopf | normally I would say that with the higher watt value |
07:52.35 | eintopf | but the terminator sounds cool enough |
07:53.09 | eintopf | (terminator) has no watt value printed, but it's high enough to burn cables ;) |
07:54.07 | eintopf | the other one has a FAN SENSCACONTROL :D |
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