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Ask Slashdot: DIY 4G Antenna Design For the Holidays? 135

eldavojohn writes "This holiday season I will return to the land of my childhood. It is flat and desolate with the nearest major city being a three hour car drive away. Although being able to hear the blood pulse through your ears and enjoying the full milky way is nice, I have finally convinced my parents to get "the internet." It's basically a Verizon Jetpack that receives 4G connected to a router. My mom says it works great but she has complained of it cutting in and out. I know where the tower is, this land is so flat and so devoid of light pollution that the tower and all windmills are supernovas on the horizon at night. Usually I use my rooted Galaxy Nexus to read Slashdot, reply to work e-mails, etc. I would like to build an antenna for her 4G device so they can finally enjoy information the way I have. I have access to tons of scrap copper, wood, steel, etc and could probably hit a scrap yard if something else were needed. As a kid, I would build various quad antennas in an attempt to get better radio and TV reception (is the new digital television antenna design any different?) but I have no experience with building 4G antennas. I assume the sizes and lengths would be much different? After shopping around any 4G antenna costs way too much money. So, Slashdot, do you have any resources, suggestions, books, ideas or otherwise about building something to connect to a Jetpack antenna port? I've got a Masters of Science but it's in Computer Science so if you do explain complicated circuits it helps to explain it like I'm five. I've used baluns before in antenna design but after pulling up unidirectional and reflector antenna designs, I realize I might be in a little over my head. Is there an industry standard book on building antennas for any spectrum?"
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Ask Slashdot: DIY 4G Antenna Design For the Holidays?

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  • 30$? (Score:4, Insightful)

    by tanveer1979 ( 530624 ) on Friday November 30, 2012 @09:08AM (#42140579) Homepage Journal

    Something like this costs 30$
    http://www.wpsantennas.com/700MHZ-LTE-4G-Antennas.aspx [wpsantennas.com]

    Ebay has things for 20-25$
    Did you look at these options before deciding to building your own?

    • Re: (Score:1, Insightful)

      by Anonymous Coward

      WTF? Seriously, what happened to /. being a place for nerds?

      • Re:30$? (Score:4, Insightful)

        by putty_thing ( 637042 ) on Friday November 30, 2012 @09:16AM (#42140609) Homepage
        Exactly, Pringles cost way less than $30
        • Re: (Score:3, Informative)

          by putty_thing ( 637042 )
          I was joking originally but just Googled [google.co.uk] it, a lot of the used 4G frequency range is pretty close to the 2.4Ghz that has been used for wifi cantennas, looks like you can build something pretty easily.
          • Re:30$? (Score:4, Interesting)

            by Z00L00K ( 682162 ) on Friday November 30, 2012 @10:18AM (#42140981) Homepage

            I would say that an antenna like a cantenna [napoliwireless.net] would be the thing to look at.

            Here's an instruction video [in.com] too.

            The main thing with a cantenna is to have a 1/4 wavelength distance between the antenna in the can and the back wall and the antenna in the can shall be a 1/4 wavelength. pin.

            Here's also a good site with another cantenna calculator [changpuak.ch].

            And when you make your cantenna you should allow for fine tuning of the position and length of the antenna pin inside the can.

        • A Chock Full O' Nuts can may be a better choice, and if there isn't one already available, well, then that geek cred is shot, as well as all the fantasies I have about living in the desolate flat nowhere. But such is the stuff of reality. Go buy them some coffee. Better cantenna.

          • by adolf ( 21054 )

            Chock Full O' Nuts didn't work as well as Bush's Baked Beans, in my early wardriving experience. YMMV (slow-clap pun intended).

        • Exactly, all the 4G phones are in the 1.8GHz to 2.5GHz range so just find out the center frequency for your phone. Then use the 300/f to get the wavelength in meters - as long as frequency is spec'd in MHz.

          Then build your Pringles Yagi. In my case 1.8GHZ yields a 17cm full wavelength driven element. That's 6.6 inches. You can do half wavelength and even quarter wavelength too.
      • Re:30$? (Score:4, Insightful)

        by Kokuyo ( 549451 ) on Friday November 30, 2012 @09:17AM (#42140623) Journal

        Nerds build stuff nobody else thought of or with material nobody ever expected to work that way.


        Nerds like to build things in unusual ways for the enjoyment of succeeding at it.

        What nerds don't do is spending hours building stuff they need that they could have shipped to them for little money and is plug and play. At least the intelligent nerds don't do that.

        Now if these products do not satisfy, that is a completely different matter.

        • by Anonymous Coward

          "Nerds like to build things in unusual ways for the enjoyment of succeeding at it."

          Which is exactly what this story is about...I detect some contradiction in your post.

          • by Carik ( 205890 )

            From the story:

            I would like to build an antenna for her 4G device so they can finally enjoy information the way I have. ... After shopping around any 4G antenna costs way too much money.

            So no, this article isn't about building for enjoyment, it's about finding an affordable way to get online. Now, perhaps $30 + shipping is within the OP's "way too much" range, but perhaps he just didn't see that item.

      • Could buy one (two would be better to allow for disassembly), use it as a reference and a benchmark for his own creation. Then return them (if not destroyed in the process).

    • by eldavojohn ( 898314 ) * <eldavojohnNO@SPAMgmail.com> on Friday November 30, 2012 @09:20AM (#42140633) Journal

      Something like this costs 30$ http://www.wpsantennas.com/700MHZ-LTE-4G-Antennas.aspx [wpsantennas.com]

      Ebay has things for 20-25$ Did you look at these options before deciding to building your own?

      If you're telling me that works and that's the best I can do, then okay, you've got it figured out and I just don't understand antennas at all.

      Like I said, I googled and looked for costs. The models that I see on your link that are $30 are 7.72” in length and look like the same things that come with any wireless router. I assume the Verizon Jetpack already has an antenna of this quality. What I was hoping for by asking Slashdot was that someone would belittle me and tell me how to build something more like this [wpsantennas.com] but without the $120 price tag since it's probably just a bunch of metal configured a certain way connected to a balun connected to the device. I know where the cell tower is from my parent's house, I just don't know how to construct something that will function better than the little device they have.

      Also, I was kind of hoping that there were really cool designs people knew of that consisted more than just "a big stick of metal you point at the tower." However, like I admitted in the submission, I don't know jack shit about antennas.

      • by Fishead ( 658061 ) on Friday November 30, 2012 @09:35AM (#42140705)

        Myself, I'm a newb radio technician, so I know where you're coming from.

        What you want is a "Yagi" antenna. Very directional and therefore, longer range.

        Search for "Cantenna"

        Also try: http://www.skyscan.ca/Antennas.htm [skyscan.ca]

        I had previously found a website that had a good modeling program to show you the lobe of radiated power, but don't have time this morning to find it again.

        I'm also not sure what frequency you want to build it for. Some sites say 700mhz, some 1800mhz.

        Hopefully someone with more radio know-how can add to the discussion. If you're near south-east BC, bring it by and we'll test the antenna on my (absurdly expensive) service monitor. I'm wanting to build a long range wifi net connecting to several buddies in town, so I'll be watching and hoping for some insightful help on this thread.

      • something more like this but without the $120 price tag

        It seems to me that if it works, it would be $120 well spent. It would improve your parents' internet connection, which is your main goal, right? It would also require a minimal time investment on your behalf, which should also be a goal for you as you did not mention making frequent visits there. Third, if something goes wrong you have a manufacturer and a vendor to talk to - rather than having to rebuild the damned thing on your own.

        One way to look at this is that if you visit once per year (you do see your parents once a year, right?) this will cost you only $10 per month. That is nothing. Besides, if you're three hours from the closest town, what are the chances you'll be able to get anything useful for building / repairing an antenna when you're out there? You seem to be about to start yourself on a project with very low probability of success for no apparent reason.

        Buy the antenna and then spend your time building them a home file server to back up their important documents instead. Much better use of time and more tangible results.

        • by pfignaux ( 39568 )
          I agree with this plan. While DIY antennas are fun to build, and I'm sure you're probably looking for something to do while at the homestead, dropping $120 on a decent antenna would be the proper thing to do for your folks.
        • by Zalbik ( 308903 ) on Friday November 30, 2012 @11:51AM (#42142085)

          I disagree. For $120 you are basically getting exactly what the OP described in one of his responses: a bunch of metal configured in a certain way.

          Antennas are one of the easiest "geek projects" to do, and if the OP has access to the materials described, it should be a fairly simple (2-4 hours) project...

          Actually, just googled "DIY LTE Antenna" and came across this [dslreports.com] . Apparently 4 hours to build, and cost all of $10.

          Sure from a pure time/money perspective, you are only saving $27/hr, but IMHO it's time well spent.

          • I only semi agree with that. Making antennas out of a bunch of wire is quite easy. However if you're after good performance then you typically want to buy something manufactured. The tolerances on antenna design to get nice high gain lobes require some very damn precise metal work, not to mention potential impedance matching though the use of expensive measurement tools and or very precisely terminated connectors on carefully measured tails (again impedance issue).

            DIY antennas typically have a very high VSS

            • by adolf ( 21054 )

              DIY antennas typically have a very high VSSR and while they are great when you need a little bit of gain, if you're aiming for something directional with lots of gain, the use of a bit of wire and a screw driver may cost you 3-10dB over many properly made products.

              If the existing antenna is almost adequate, then perfection is not all that important. Any meaningful amount of gain, combined with improved placement, is entirely likely to be sufficient to make a marginal connection reliable.

              Indeed, depending o

              • *: "Very well" meaning that I went from receiving one ATSC station some of the time, to four stations all of the time. Perfect? No. But it was better than the bunny ears and tunable UHF loops I also had laying around by a practical factor of 4, at least**.

                **: Put that in your SWR meter and smoke it.

                Puhleese I live in a country where it was standard practice to throw a bicycle wheel on the end of the antenna to pick up a few new stations that didn't quite fit in the normal tuned range of the UHF antennas of the time.

                I fully agree with you. If you're after a marginal improvement then whack some crap together and try point it in the right direction. But don't confuse anything you'll make at home with a $120 antenna from the store.

        • by toygeek ( 473120 )

          I completely agree. Antenna engineering is not a trivial matter and if the proper R&D has gone into that $120 unit and it actually works, then its worth double that.

          Anything you homebrew will end up being a copy of it, and probably not as good unless you've built a yagi before and know exactly what you're doing.

      • You should also have a look at this guy: wa5jvb [wa5vjb.com] who makes and sells PCB antennas. They are very cheap indeed. Whether you want a Yagi or a log-periodic depends on the frequency/frequencies you want to receive.
      • If you look closely, the lengths of the antennas themselves are the same on the one you linked to the one that the GP linked. That's because the frequency an antenna is tuned to receive depends on the length of the antenna itself. A simple dipole made out of a coathanger would work fine, as long as they're the right length and put in the right place.

        Now, putting a simple antenna like the one described in probably won't actually improve things, because her cellular modem is probably located in a dead spot, w

      • by Wovel ( 964431 )

        You don't want the $30 omni antenna. The directionals on there are more like $80.

        A well built cantenna will cost less and work better.

        • by Wovel ( 964431 )

          Someone below points out the Verizon frequencies are around 700mhz. You will want a Yagi and not a cantenna. Should be easy to do. Yagi calculators are all over the Internet.

      • I'm not sure if this antenna does what you need, but http://www.l-com.com/item.aspx?id=41160 [l-com.com] , 800 MHz - 2.5 GHz 11dBi Log Periodic Broadband Yagi Antenna $60. If you have the 700MHz LTE that may not work.

        I've been using l-com since early 2000 when they were still Hyperlink Technologies and can attest to the quality of their products. We had many of their antenna up for 8 years, only switching them to another model of their product in the 5GHz range so we could get higher speeds with newer radios. They have

      • A small active antenna can give tremendous improvement over a passive antena. calculate dipole length based on your frequency, and then look up some simple circuits for active antenna.,
        From your post it appeared that you wanted something cheap.
        20$ will give you some real good antennas from ebay

    • by dj245 ( 732906 )
      I have one of these unpowered antennas. It boosted my signal by about 2 bars (out of 5) on average.

      My company has some field engineers who frequently spend time inside construction trailers (usually steel ones like this [vegasequipment.com] which are then located inside steel buildings. Their work is never near a metropolitan area and usually in the middle of nowhere with poor cell reception. They use the more expensive antenna+powered amplifier systems and can usually get a usable signal even when I can't.
    • The $30 antennae linked are omnidirectional, which isn't ideal in this situation.

      A directional antenna is a better solution in this case - neither side of the RF link is going to move (much). Directional antennae are also linked, but they're $80. (In my opinion, that's right on the edge of the make vs buy tipping point.)

      The easiest antenna to construct will simply be a reflector for the existing antenna. The easiest way to do that is probably to put a piece of sheetmetal near the antenna, opposite the di

    • Not knowing what Verizon uses for bands, looks to me like the cheapest he'd get away with on that site is $79.95. Remember, he is 3 hours from the nearest town.

    • For that price range I would recommend the MAGLTEANT http://www.wpsantennas.com/MAGLTEANT---Magnetic-Mount-Antenna-for-LTE.aspx [wpsantennas.com]. The advantage of this antenna is that you could mount it outside where there is typically stronger signal. You would need the antenna as well as an adapter cable (these are device specific). wpsantennas.com has adapter cables for most Aircards modems.
  • ARRL (Score:5, Insightful)

    by Anonymous Coward on Friday November 30, 2012 @09:15AM (#42140599)

    Start with ARRL (http://www.arrl.org/)
    Antenna Handbook: http://www.amazon.com/dp/087259694X/
    *The* Handbook: www.amazon.com/dp/087259419X/

    • by Anonymous Coward

      If you are not familiar with radio and antennas, I would not recommend trying to use this book. I am a ham myself. You might go to www.eham.net or www.hamradioforum.net. The hams there will probably be glad to help you design one.

  • by Anonymous Coward

    As the Jetpack is so small, could you mount it inside a parabolic dish - i.e. WOKtenna?

    See: http://www.usbwifi.orconhosting.net.nz/

  • by robot256 ( 1635039 ) on Friday November 30, 2012 @09:16AM (#42140611)

    At the higher frequencies like 1.3GHz (LTE), the wavelengths are so small that the corresponding antenna features are also very small. They have to be extremely precise if you want the gain to actually be at the right frequency, and even then it usually takes some trial and error. Do you have a chemical or laser PCB etching machine, and a cellular antenna analyzer (Saw one SUPER cheap on ebay for $300 once). Otherwise, just making random things could result in reflections damaging your transmitter. This isn't like putting together a 1/4-wave dipole on 2 meters.

    But you could try fashioning a parabolic reflector dish and put your existing antenna in the center of it. I've heard of people doing that with cell phones and wi-fi adapters before.

    • by Svartalf ( 2997 )

      Unless this is as much an educational exercise as anything else, they're going to want to skip even what you suggested there on DIY as the risks to damaging the unit's moderately high- and for what they'd have to spend for doing a DIY antenna the right way, they're going to spend as much or more than buying a 3G or LTE repeater kit (Typically around $400-800...).

      The original poster of the question will thank themselves (as will their parents) for some time to come if they did that instead. Especially with

    • But you could try fashioning a parabolic reflector dish and put your existing antenna in the center of it. I've heard of people doing that with cell phones and wi-fi adapters before.

      To me this sounds like the easiest approach. But, the reflector doesn't necessarily need to be parabolic, see, for example http://en.wikipedia.org/wiki/Yagi-Uda_antenna [wikipedia.org] .

      Also, before trying to build an antenna, one should probably experiment with placement of the current antenna. Even with LoS and flat terrain (no vertical reflectors), there will still be a ground reflection that can double or zero your received signal.

    • by adolf ( 21054 )

      Verizon's LTE (which is the context here) is, always, 700MHz-ish, which is well within the grasp of a tinkerer. And I don't see anyone asking for perfect; all anyone really needs here is functional.

      To use a computer analogy: No home user cares how well a Cat6 cable performs on a Pentascanner or a Fluke network analyzer. They care that they can plug it in and have reliable data transfer betwixt whatever real gear happens to be at either end.

      Similarly, nobody cares how the antenna performs on a multi-kilob

  • by emmjayell ( 780191 ) on Friday November 30, 2012 @09:18AM (#42140627)

    How about posting some pictures of the milky way? I've only barely seen it once while on Hilton Head island.

    http://www.dslreports.com/forum/r27484816-DIY-3G-4G-LTE-Yagi [dslreports.com]

    http://bcbj.org/antennae/lte_yagi_diy.htm [bcbj.org]

  • by StoneyMahoney ( 1488261 ) on Friday November 30, 2012 @09:21AM (#42140635)

    From my limited knowledge of physics, it sounds like a custom-built cantenna waveguide would be perfect for you, although I can't help you with the design - the length and diameter of the can and the positioning and protrusion depth of the tranceiver element need to be calculated depending on the frequency of the signal you're trying to pick up. I imagine there are formulae or even online calculators for this stuff online, so if you can find those you may only need to find out the frequency band you're trying to select to get the design calculated. Then it's a matter of making it precisely enough.

  • by Anonymous Coward

    your library should have a copy of 'The Amateur Radio Handbook'. If I remember correctly, there is some sort of log periodic design calculator that will design a fairly broadbanded yagi that can be adapted to different frequencies.

  • LTE yagi (Score:5, Informative)

    by HoaryCripple ( 187169 ) on Friday November 30, 2012 @09:30AM (#42140675) Homepage

    http://bcbj.org/antennae/lte_yagi_diy.htm [bcbj.org]

    Decent instructions for an LTE yagi.

    • If you dont know how to ground this properly please ask or hire someone who knows what they are doing. You could kill someone with improper grounding in case of a lightning strike.

    • by Anonymous Coward

      numbers should be similar for a cubicle quad. At LTE freqs it shouldn't take up the whole back deck like the17 element cubicle quad I built for 2M back when I was 14 or so :)

  • You could just... (Score:5, Insightful)

    by Anonymous Coward on Friday November 30, 2012 @09:41AM (#42140737)

    scrap the tons of copper and steel you have, then buy an antenna.

  • by Gordonjcp ( 186804 ) on Friday November 30, 2012 @09:47AM (#42140777) Homepage

    If you get a USB adaptor for your 4G signal, and stick it outside on a long pole nice and high up plugged into a USB extension cable it'll work just fine. Remember to tape the whole thing up with self-amalgamating tape (not lx tape) to keep the water out, and leave a drip loop where you bring the cable into the building.

    It's the simplest thing that could work.

    • And remember, a drip loop does not involve a cable tie. Just sayin...

      • And remember, a drip loop does not involve a cable tie. Just sayin...

        It *does*, but it's really important to put it in the right place ;-)

  • by Anonymous Coward

    They don't really advertise this service, but you can get Home Fusion from Verizon. If you sign up, they'll send a professional out to install a 4G antenna. A little on the pricey side but if you are a heavy internet user it's not a bad deal:


  • use this website for the math: http://www.changpuak.ch/electronics/yagi_uda_antenna.php [changpuak.ch] then simply use the wire you have to build the yagi antenna. highly directional with a large forward lobe this should do the trick. I see the boom length is small for 800/1900Mhz (I think that's 4G freqs). Naturally purchasing one will save the time/effort to solder/clamp the elements to the boom and the coax to the antenna/connector but there's nothing more satisfying that a bit of home-brew kit. HTH
  • What band? (Score:3, Informative)

    by Anonymous Coward on Friday November 30, 2012 @10:17AM (#42140977)

    LTE doesn't really mean anything for an antenna designer. It's all about modulation type, rate and protocol. What matters for antenna design is center frequency and to some extent bandwidth.

    In North America, there are several LTE bands in use: 700/800, 1700/1900 and 2500 MHz. If you can, find out what bands Verizon uses in your area.

    Don't buy a cheap 2dBi antenna. The antenna in the module is probably around 0dBi already so it won't help much. What you want is a directional antenna you can point at the tower to get a big improvement. The good news: this IS something you can build yourself. If you need to cover all three bands, you'll might need a log-periodic. If it's one frequency you can build a Yagi and it will do better than the log-periodic.

    Books for antenna design for amateurs:

    AARL Antenna Book

    AARL Wire Antenna Classics

    There are more books that are written at various levels. I suggest the AARL books because they assume you have some technical knowledge but aren't necessarily an electrical/electronics engineer. You can also find free designs on-line for antennas made by radio amateurs. These are often very helpful and tell you exactly how to build their antennas and show you pictures. Some engineering and science libraries will let the public come in and peruse their books. If so, you can go there with a pad and pencil and design your antenna right in the library.

    Since your antenna will be bidirectional (same antenna for up and downlink) you will need to use low-loss cable to connect them up. This is very important because if you use the wrong cable or too long a cable, you may overcome the gain of the antenna! That's another reason to build a high-gain antenna.

    Pointing a high-gain antenna at the tower also gets your RF out of the house where it's less likely to interfere with other stuff that might be in your house, like phones.

    • I would add the old "Antenna data reference manual" [amazon.com] and a somewhat newer book by the same author, Joseph Carr, Practical Antenna Handbook [amazon.com].
    • LTE doesn't really mean anything for an antenna designer. It's all about modulation type, rate and protocol. What matters for antenna design is center frequency and to some extent bandwidth.

      and polarization.

    • by adolf ( 21054 )

      What band?

      FFS, if anyone read TFS, they'd have seen that it is a question about Verizon LTE, which only operates in one band.

      LTE doesn't really mean anything for an antenna designer.

      It does if the antenna designer isn't a douchebag who can't read, since (again) the words "Verizon LTE" are very specific about what, exactly, is wanted and required.

      (Sometimes I think the problem with engineers is that they expect everyone to speak their language and then spoon-feed them specific, concise instructions, all whi

  • Find out where the closest 4G transmitter mast is and then move the router to that side of the house, preferably with a little additional material between it and the outside. Maybe put the router upstairs. You can always pull cables and stick an additional wifi routers around the house to provide complete coverage.

  • by StatureOfLiberty ( 1333335 ) on Friday November 30, 2012 @10:41AM (#42141217)

    To answer your question about digital TV antennas:
    Despite the marketing implications, there really is nothing different about antennas for Digital TV. The encoding is not important. The frequency is the main factor and that has not changed substantially. Most digital TV stations are on the UHF band around where I live. So, if you are lucky, you can get by with just a simple UHF antenna if the stations are nearby.

    Here is where you can find your nearby stations:
    http://transition.fcc.gov/mb/engineering/maps/# [fcc.gov]

    I built a simple 4 bay bow tie antenna for UHF. Mine looks like the one pictured at the top of this thread.
    http://www.city-data.com/forum/consumer-electronics/614073-how-build-your-own-4-bay.html [city-data.com]
    Here is a really nice example of one:
    http://www.dtvusaforum.com/dtv-hdtv-reception-antenna-discussion/8629-kosmic-antennas-superquad-4-bay-bowtie.html [dtvusaforum.com]

    I also built a folded dipole for VHF: Here is an example:
    http://crdahl.com/antennas/dipole.html [crdahl.com]

    My stations were fairly close by. These two antennas are not high gain antennas. I added a Winegard preampt to bring up the signal a bit. I have been very pleased. So, in summary, there is nothing different. Just look up your local stations and pick an antenna based on band(s) and distance.

    • Despite the marketing implications, there really is nothing different about antennas for Digital TV. The encoding is not important. The frequency is the main factor and that has not changed substantially.

      I'd have to disagree with you. The changes are a matter of degree rather than principle, but they are real.

      VHF-lo has be largely (but not completely) eliminated, meaning new (digital) VHF antennas are VHF-hi only, rather than full range.

      UHF channels 52-69 have been eliminated, meaning many UHF antennas tha

      • Yes, the user will have to pick the antenna appropriate for their situation. If your antenna didn't receive UHF before, it will need to now. But there is nothing new here. You had to pick the antenna appropriate for your situation when the stations were analog as well.

        Like I said before:
        "Just look up your local stations and pick an antenna based on band(s) and distance."

        I guess I could add pick it based on direction as well. In my case, all of the transmitters were in the same general direction and

        • I don't think the power reductions are much of a factor.

          You're just speculating. I am not. Broadcast radius has been reduced. Go read up on the subject if you don't want to believe me.

          Concerning preamps. if you buy a good preamplifier (mine is a winegard that is mounted up at the antenna) it really can help. My favorite channel changed from unwatchable to a good rock solid picture.

          Whether a preamp helps OR HURTS depends on the sensitivity of your tuner, the noise figure on the preamp, and the di

  • I would suggest to design and build a log periodic antenna. You probably need bandwidth, and some gain. Log periodic antenna patterns can be printed on a PCB, and will last longer than a Pringles can. A search on google will show up to you several antenna examples and antenna calculators.
  • There's some good advice about the antenna above, but you may find the the quality of the coax and it's length have more affect on performance than the type of antenna you use.

    You might even be better puting the entire router/antenna system up high, and running power and ethernet down. (Of couse putting the whole thing in a waterproof plastic box.)

    You can prototype it with a laptop and a ladder.
  • I've got a Virgin Mobile MC760 3G USB Modem, and am wrapping up using a wok skimmer as a parabolic antenna for it. I'm using a 11" skimmer, and went from two to four bars signal. Just have to finish the mounting and I'll be able to use it with our house wifi network through our router (it has a usb port and with dd-wrt I can use that for a failover connection when Comcast goes down). Here's the basic idea of it: http://geobray.com/2010/02/07/woktenna-for-3g/ [geobray.com] Same idea, using USB wifi adapters: http://ww [orconhosting.net.nz]
  • ANOTHER THOUGHT (Score:2, Interesting)

    by Anonymous Coward

    Another thought comes to mind. . . what is the cause of the interruptions the parental units are experiencing with the set-up they already have?

    How far is it to the tower? what is the noise floor like between the tower and their house? [What happens at your neighbors house that may interrupt the signal gettting to your parents house?] Are they enjoying any other wireless-frequency obtained signals, like satellite? Do any of your neighbors enjoy broadcasting CB or single side band radio? Around their ante

  • While 4G was 2.3 Ghz, microwave range and therefore a cantenna style waveguide would be good, LTE is 750 Mhz. For LTE you would want a more conventional desig.s. (Antenna designs are pretty much the same until you get about 1Ghz or so, then you use different designs.)
    • 4G is a different frequency range for each carrier. For AT&T and Verizon it is in the 700mhz range. For T-mobile it is 1.7, 2.1GHz, For Sprint/Clear it is 2.5-2.7GHz (although they will be switching to 1900mhz and or 900mhz over the next few yrs)
  • Unless the frequency turns out to make this design prohibitavely small, try a Moxon: http://www.moxonantennaproject.com/design.htm/ [moxonantennaproject.com]

    I built one for OTA TV broadcasts (somewhere in the neighborhood of 500 MHz) using spare wire I had laying around and had good results. There's a calculator program at that URL that will give you the dimensions of the elements for any given frequency. All you have to do is bend the wire and find a way to keep them at the required distances.
    If your antenna needs to be really smal

  • HI all, This is Mike from wpsantennas.com. If anyone has questions on specific antenna options let me know. We have quite a few different options available ranging from a $35 for a magnetic antenna http://www.wpsantennas.com/MAGLTEANT---Magnetic-Mount-Antenna-for-LTE.aspx [wpsantennas.com] that can typically boost your signal 1-2 bars (10-12dB) to a high gain yagi like the 477-yb for maximum gain. The current price on the 477-yb http://www.wpsantennas.com/477-YB---Digital-Antenna-700-MHz-Yagi-Directional-4G-Cellular-Antenna [wpsantennas.com]
  • "Although being able to hear the blood pulse through your ears and enjoying the full milky way is nice, " - Irrelevant to the question.

    "...this land is so flat and so devoid of light pollution that the tower and all windmills are supernovas on the horizon at night." - Turn down your bloom settings.

    " Usually I use my rooted Galaxy Nexus to read Slashdot, reply to work e-mails, etc." - Irrelevant to the question. Who cares what device you use and whether it's rooted?

    And more. You could have said this in about

  • ...how are you going to plug it into your phone? I'd like to know having a galaxy nexus and a shoddy signal.
    • Hi this is Mike from wpsantennas.com. There are 2 key parts to the antenna setup. 1. The antenna itself of which there are many options which I would be happy to discuss (every situation is different based on tower location, wireless carrier etc) and 2. The antenna adapter cable http://www.wpsantennas.com/antenna-adapter-cables.aspx [wpsantennas.com]. Most aircards/mifi's have a small rf port that is designed to connect an external antenna to. There are numerous different adapter cables and they are device specific. Unfortun
  • One of my friends did exactly what you're describing - he works on an offshore oil rig, and used a high gain antenna pointed at land to get cellphone service. It worked great... until he came ashore and his phone didn't get a signal.

    Turns out the RF connector in the phone is only there for production testing of power/RF compliance - it's only intended to be connected to once, and it's not designed for daily connections/disconnections. The datasheet for one replacement connector we found was only rated for 1

    • In some cases this is correct. We have many adapters listed on our site that are listed as having weak ports and the customer needs to click that they have read the warning before purchasing the adapter. One example of this is the Motorola V3 Razr. This phone had a very weak port and often times would stay in the "connected setting" even after taking out the adapter. This is not the case with most phones aircards however. Currently there are a few different phones that have this "weak" port and no aircards
  • by drwho ( 4190 ) on Friday November 30, 2012 @12:38PM (#42142767) Homepage Journal

    To be honest, there's a time an place for homemade equipment, and this isn't it. You've admitted this isn't your area of expertise. Neither is it your parents'. If it breaks, what are you going to do? The idea of using a a Pringle's can is absurd. Get a strong, professionally built antenna and mount.

    Some things to think about: the higher gain of a highly directional antenna comes from focusing the energy more tightly than a lower-gain directional antenna. The more directional an antenna is, the more precision and accuracy must be used in aiming it. It will also, presumable, but outside in the elements, with wind, rain, snow, animals, and sunlight. All of these can degrade the antenna or interfere with its aiming. Therefore, a very strong mount must be used when using a high-gain antenna.

    My suggestion is to go to your parents' house well prepared, with antennas of differing gain. Use the one with the lowest gain which gives a moderately strong signal. For instance, if 5 bars means the strongest possible signal, use the antenna that gets your 4 bars. The antenna which gives you 5 bars is most likely providing unneeded signal strength, at the cost of requiring better aiming. This doesn't mean you should use the antenna that provides one or two bars, however, because the extra signal strength might be needed during strong rain or snow. you should also go prepared with a proper knowledge of antenna installation, including lighting protection and grounding, use of a drip loop, know the signal loss of the cable you are using, etc. You should already have calculated the path loss from the cell site to your parents' house, and know the receive sensitivity and transmit power of the cell site and the 4G device for your parents' house. You can then figure out if this is in the realm of possibility. When you go to do the installation on site, bring spares, the proper tools, some general tools, gloves, clothing appropriate to the task, safety gear, and make sure that you have health insurance coverage.

    It's easy to do a bad job of antenna installation. Sometimes you get lucky, and it will be sufficient -for a while. But then it will fail and you're up a creek without a paddle. Spend the money and do it right, or hire a professional to do it. These are your parents, after all, you don't want to disappoint them.

  • The thing with my "hotspot" is, there is no place to connect an external antenna to point at the cell tower. I intend to one day soon try an experiment where I put the hotspot at the focal point of one of my old Dish Network dishes and see if I can get better signal.

    I live in an Internet desolate place and we use an AT&T "hotspot" that connects to a cell tower and is a little Wi-Fi "router" (that seems to only have one route, but that's a different rant). AT&T recently upgraded a cell tower in my

  • I think what you're looking for is the 30' tall Lightning Bringer 2000!

    (House) Fire Walk with Me!
  • What's the legality of building your own cell phone antenna, though? (If that matters to you.)

    I've build several cantennas for 2.4gHz WiFi. The dimensions of both of the commonly-recommended cans (pringles and chock-full-of-nuts) are not ideal. The length-width ratios are off. I can see a few hundred WiFi signals off my balcony, including ones across San Diego Bay, a couple miles.

    I found a can that is ideal, and the coffee (from a local San Diego coffee roaster) is excellent:

    http://www.caffecalabria.com/cof [caffecalabria.com]

    • Oh, forgot to mention, I don't actually use an adapter cable. Instead (for WiFi) I use a small external USB-connected WiFi adapter (since my Macbook doesn't have an atenna connector) and a small metal adapter from the WiFi adapter connector to the N-connector on the cantenna. Zero cable length. The USB adapter just hangs on the side of the can. Cable loss can be considerable at these frequencies. Obviously, suitable for indoor use only. If you are using a USB dongle, and it's not very heavy, this could be

  • by PPH ( 736903 )

    Look for the ARRL Antenna Book [arrl.org]. Its a good reference for DIY hobby type projects.

    Based on the commercial offerings, I'd look at building a log periodic Yagi. That should give you decent gain plus directionality over a wide frequency range. If the gain from one beam isn't enough, you could build several in an array. Its all in the above book.

    Most of the skill you will need will be in metal/plastic working. At the frequencies in question, a few millimeters will affect the antenna pattern and gain, so atten

  • I know this isn't what you were looking for based on the summary, but you never know, sometimes there are options you've never thought about, so I'll posit it anyway:

    Verizon Wireless offers HomeFusion Broadband [verizonwireless.com] for a professionally-installed, rooftop-mounted 4G home broadband service. It sounds like it's ideally suited to your parents, and for $6.99/mo, you get the peace of mind knowing that they will send a technician out to fix any issues that may arise.

    I don't know if it's in your parents' price range (i

  • I understand DIY provides a fun project, but you can buy what you're looking for directly from Verizon for under $100. Coincidentally, that puts it in the right price range to make it a great Christmas gift. Since you're going home for Christmas. Something you buy will be more rugged, you can mount it outside on the roof or the side of the house and run a cable back inside to the hotspot/usb modem.

Never buy what you do not want because it is cheap; it will be dear to you. -- Thomas Jefferson