DocScrutinizer05 changed the topic of #qi-hardware to: Copyleft hardware - http://qi-hardware.com | hardware hackers join here to discuss Ben NanoNote, atben / atusb 802.15.4 wireless, and other community driven hw projects | public logging at http://en.qi-hardware.com/irclogs and http://irclog.whitequark.org/qi-hardware
<Mike25226> hmmmm... Do you think researching/making an amplifier would be a better option since, like you said, PCB antennas are fairly standard
<whitequark> no
<whitequark> these are commodity hardware
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<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
<whitequark> what exactly do you want to achieve
<Mike25226> better range
<Mike25226> as well as good signal level
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<whitequark> and you want an omnidirectional antenna with an amplifier?
<Mike25226> yeah
<whitequark> pointless
<whitequark> and illegal, too
<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)
<whitequark> you could a) use a directional antenna b) set up a network out of several routers
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<Mike25226> Inverse square law?
<whitequark> yes
<DocScrutinizer05> generally an antenna with good gain would help. Hardly feasible as PCB antenna though
<DocScrutinizer05> decen ground plane antenna has quite a bit of gain from 2D (omni)directional
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<DocScrutinizer05> however will fail when you want to go vertical between AP and client
<DocScrutinizer05> I.E. a ground plane antenna in attic is rather contraproductive for clients inhouse "under" the antenna
<DocScrutinizer05> use MIMO
<DocScrutinizer05> it basically acts like an adaptive virtual directional antenna
<Mike25226> hmmm
<Mike25226> MIMO is a multiple antenna design right?
<DocScrutinizer05> yes
<Mike25226> Wouldn't a wireless card have to support it? I'm guessing it's not as simple as MAIN--= , AUX--= , = is 2 antennas
<DocScrutinizer05> yes, and many wireless cards _do_ support MIMO
<whitequark> actually, you would frequently encounter cards with literally these ports
<DocScrutinizer05> and it is like they have 2 antenna connectors
<whitequark> my latop has one
<DocScrutinizer05> recently I've seen APs with even 3 or 4 antennas
<DocScrutinizer05> :nod:
<DocScrutinizer05> unclear if that's one antenna for 2.4 and one for 5, or MIMO-2 with 2 multiband antenna connectors
<DocScrutinizer05> often it's even configurable in vard's registers
<DocScrutinizer05> card's*
<whitequark> I think 2.4 and 5 usually use the same antenna
<Mike25226> there is only one PCB antenna and both MAIN and AUX go to it
<DocScrutinizer05> usually, but not generally
<whitequark> read some appnotes, they say it's good enough
<DocScrutinizer05> 2x2
<DocScrutinizer05> suggests MIMO
<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<<
<Mike25226> interesting....
<Mike25226> my laptop only uses 1
<Mike25226> watching a disassembly video to verify
<whitequark> crack it oopen
<DocScrutinizer05> wMIMO only makes sense with multiple physically distinct antennas. When your laptop only has one, it can't do MIMO
<DocScrutinizer05> -w
<DocScrutinizer05> conecting both antenna jacks of a mimo card to same antenna is contraproductive
<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
<Mike25226> only has one
<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
<Mike25226> Can a PCB antenna act as 2?
<DocScrutinizer05> the card will (either automatically or by config) shut down the "aux" antenna and use only one
<Mike25226> I imagine that would cause issues being that close
<DocScrutinizer05> no, no antenna can act "as 2"
<Mike25226> well, with a PCB... couldn't it be done?
<DocScrutinizer05> sorry?
<Mike25226> just tracing on back and front of PCB
<DocScrutinizer05> that's two antennas, not one
<DocScrutinizer05> however you must keep the antenna area clear of all conducting objects and traces, also of a second antenna
<DocScrutinizer05> IOW one antenna per dedicated area
<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?
<DocScrutinizer05> this is one antenna in that picture
<DocScrutinizer05> the bottom side of the PCB MUST kept clear of *all* traces and conducting objects
<Mike25226> ahhh, gotcha
<DocScrutinizer05> of course you can have two of those on one PCB, with a small distance between them
<Mike25226> so that confirms that my laptop is only using one antenna, even though both main and aux connect to it
<Mike25226> you mean side by side?
<DocScrutinizer05> I guess that's pretty wrong a thing to do. Unless the data sheet of the card *explicitly* states to do so
<DocScrutinizer05> yes, side by side
<DocScrutinizer05> ideally in more than 1/2 the length of antenna as distance between them
<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).
<DocScrutinizer05> you MUST NOT split antenna cables
<DocScrutinizer05> like Y-cable
<DocScrutinizer05> this is generally absolutely forbidden
<DocScrutinizer05> so when your laptop has two antenna connectors, it quite likely has two antennas
<DocScrutinizer05> unless some jackass retrofitted the WLAN DIY without having faintest clue
<kristianpaul> wpwrak: had you had tiem for trying docker?
<Mike25226> Made this picture with 3 figures. Figure 1 is how my laptop is setup http://oi61.tinypic.com/402uw.jpg
<Mike25226> Figure 2 is what I am thinking I can do. Figure 3..... I doubt
<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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<DocScrutinizer05> adamnt rule of RF: one connector, one cable, one antenna
<DocScrutinizer05> you cannot do Y-cables
<Mike25226> hmmm... then lenovo really messed up.... which might explain why my signal isn't better
<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
<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
<DocScrutinizer05> and of course this only makes sense when the antennas are actually made for only one band and can't handle the other
<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)
<DocScrutinizer05> no, that's not exactly how it works
<Mike25226> do cards only probe when requested to do so?
<DocScrutinizer05> the "advantage" is that the antennas get the signal they can handle.
<DocScrutinizer05> for the antenna it's irrelevant if the card is "probing" or talking or listening
<Mike25226> Is proximity of the 2.4GHz and 5GHz antennas important? Should they be some what distanced?
<DocScrutinizer05> do you even have 2.4 and 5GHz antennas?
<DocScrutinizer05> look, I'm not looking forward to discussing all possible permutations of configuring a multiband MIMO system, with all the gotchas this introduces
<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"
<DocScrutinizer05> antenna *design* is an art rather than a science. Some even say it's voodoo
<Mike25226> I plan to purchase 2 new antennas
<Mike25226> or make them myself for fun
<DocScrutinizer05> and where do you plan to place those?
<DocScrutinizer05> mind you, they need to stay away a few cm from *all* conductive materials
<DocScrutinizer05> even isolated ones
<whitequark> my laptop somehow fares fine despite a solid aluminium lid
<whitequark> with the antennas at the very bottom of the screen
<DocScrutinizer05> well, when you *know* what you're doing, you can even integrate the antenna into the aluminium case
<DocScrutinizer05> but then user MUST NOT "hold it wrong" X-P
<DocScrutinizer05> the joy of doing RF tests in freefield, without anything resembling sth annoying like a user's hand ;-)
<DocScrutinizer05> "the device works perfectly, unless a planet is near"
<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
<Mike25226> I plan to place the antennas flat down on both sides of the keyboard
<DocScrutinizer05> I guess that's about the worst place for antennas you could possibly find in a laptop
<Mike25226> that's where lenovo placed the one antenna lol
<DocScrutinizer05> assuming the kbd has an alu or steel base, and below the antennas would be main PCB, right?
<Mike25226> screen casing is metal
<DocScrutinizer05> see above
<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
<DocScrutinizer05> sorry there's no simple answer to your problem
<DocScrutinizer05> odds are whatever you implement DIY in good failth will be inferior than what lenovo implemented
<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
<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?)
<Mike25226> well, like I said, they use one antenna (or single small PCB). It is oriented horizontally (flat) to the right of the keyboard
<Mike25226> Whole body is aluminum except the surface with touchpad and keyboard
<DocScrutinizer05> that's all pretty fine but not sufficient info for me to recommend anything better than I already did
<DocScrutinizer05> "there's a small PCB and two cables come from that" is no info an EE can use to give any recommendations
<DocScrutinizer05> for all I know the "small PCB" might even have TWO antennas on it
<DocScrutinizer05> impossible to tell from the available info
<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"
<DocScrutinizer05> I understood that as "under the kbd" not as "to the right/left of the kbd"
<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),
<Mike25226> it's to the right of the kbd
<Mike25226> not under the kbd
<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
<Mike25226> Btw, thanks for your help. Really appreciate it, and I am learning some things I did not know before
<DocScrutinizer05> and excuse when I'm wrong here, but to me it seems you didn't understand what's a band splitter
<DocScrutinizer05> so your "small PCB" in fig3 is pretty unspecific
<Mike25226> Oh, I was under the impression it was advantageous to have them separated
<DocScrutinizer05> no it isn't
<DocScrutinizer05> sorry afk, busy
<Mike25226> k, thanks again for the help
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<DocScrutinizer05> he's gone, nevertheless prolly the term "band splitter" isn't exactly to the point, rather "frequency-separating filter" or "crossover"
<DocScrutinizer05> or diplexer
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<wpwrak> kristianpaul: hmm no, didn't need to make any mini-VMs yet :)
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<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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<ahmed89_> m
<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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<eintopf> normally I would say that with the higher watt value
<eintopf> but the terminator sounds cool enough
<eintopf> (terminator) has no watt value printed, but it's high enough to burn cables ;)
<eintopf> the other one has a FAN SENSCACONTROL :D
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