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

samzenpus posted about a year ago | from the tune-in dept.

The Internet 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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30$? (3, Insightful)

tanveer1979 (530624) | about a year ago | (#42140579)

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:30$? (1, Insightful)

Anonymous Coward | about a year ago | (#42140597)

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

Re:30$? (4, Insightful)

putty_thing (637042) | about a year ago | (#42140609)

Exactly, Pringles cost way less than $30

Re:30$? (3, Informative)

putty_thing (637042) | about a year ago | (#42140639)

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$? (3, Interesting)

Z00L00K (682162) | about a year ago | (#42140981)

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.

Re:30$? (2)

rickb928 (945187) | about a year ago | (#42140935)

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.

Re:30$? (2)

kilodelta (843627) | about a year ago | (#42141355)

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$? (3, Insightful)

Kokuyo (549451) | about a year ago | (#42140623)

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.

Re:30$? (1)

Anonymous Coward | about a year ago | (#42140667)

"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.

Re:30$? (2)

Carik (205890) | about a year ago | (#42140769)

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.

Re:30$? (2)

foniksonik (573572) | about a year ago | (#42140631)

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).

Is a 7 Inch Swivel Blade Really Worth $30? (5, Interesting)

eldavojohn (898314) | about a year ago | (#42140633)

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.

Re:Is a 7 Inch Swivel Blade Really Worth $30? (4, Informative)

Fishead (658061) | about a year ago | (#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.

Re:Is a 7 Inch Swivel Blade Really Worth $30? (5, Informative)

olsmeister (1488789) | about a year ago | (#42140761)

If it's Verizon 4G LTE, it should be 700 MHz. They use 850 MHz and 1900 MHz for their 3G stuff.

Re:Is a 7 Inch Swivel Blade Really Worth $30? (0)

Anonymous Coward | about a year ago | (#42140875)

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.

That's one of the three good options.

The others are a parabolic dish (made of wire mesh or kitchen foil over a frame made of wood, stouter wire, or whatever, fed with a bipole, biquad, or whatever) or a SBF (like this [frars.org.uk], but bigger to suit the wavelength of your 4g service).

Re:Is a 7 Inch Swivel Blade Really Worth $30? (4, Informative)

Andy Dodd (701) | about a year ago | (#42141075)

A cantenna is NOT a Yagi. It's a waveguide antenna.

And a cantenna at 700 MHz is barely feasible. Anything with acceptable gain is going to be absolutely gigantic. You would need a proper Yagi at this point.

Re:Is a 7 Inch Swivel Blade Really Worth $30? (1)

packrat2 (686953) | about a year ago | (#42141689)

  any comment onna phazed array antenna?

  or are we still feg specfic ?


Re:Is a 7 Inch Swivel Blade Really Worth $30? (4, Informative)

LWATCDR (28044) | about a year ago | (#42141763)

I would go with a Yagi or a multi element beam. http://en.wikipedia.org/wiki/Yagi-Uda_antenna [wikipedia.org]
You could start out with just a half wave dipole .
Here a a very good site to get you started.
http://www.antenna-theory.com/ [antenna-theory.com]

Re:Is a 7 Inch Swivel Blade Really Worth $30? (2)

R_Harrold (669587) | about a year ago | (#42143883)

I'd say to go with a quad array of helical antennas. (See http://www.slvrc.org/902band/quadhelix.htm [slvrc.org]) High gain and if you design for 800Mhz it'll cover both the 700 and 850 in a reasonable size range, plus they are extremely forgiving (Yagis tend to be somewhat picky with regards to the design frequency and don't do real with wide-bandwidth signals). Hunt up any Amateur radio operator and they will talk your ear off regarding antenna design, and if you luck into one who has done ATV (Amateur TV) work they probably have some experience designing antennas up in that range. Many folks will tell you that "microwave is hard", but it's become much easier over the past few decades, plus there is the fact that conventional antenna designs that worked well for frequencies below 800Mhz just don't do real well at the higher frequencies (Wide 4 MHZ bandwidth support at 144MHz just doesn't translate well up at 2Ghz...) Robert

Re:Is a 7 Inch Swivel Blade Really Worth $30? (1)

museumpeace (735109) | about a year ago | (#42142509)

Wikipedia perhaps, but a few other sites as well, will give you a list of frequencies used in 4G...its quite a range and I have yet to find the list that tells you which carriers own which bands...and some of the bands are reserved for future use. I googled and got the list because I too live too far out of town to get cable but do have weak and variable 4G signal...weather and season matter and can make the signal go from 4bars of 4G down to 3 bars of Edge...I will report on results here if I ever get around to ripping out the preamp in my used satellite dish and putting the modem [I got the ATT sierra wireless cause thats who had the better tower location for me] once the dish aperture is > a wavelength, you should get some gain.

what's wrong with spending $120? (3, Insightful)

damn_registrars (1103043) | about a year ago | (#42140729)

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.

Re:what's wrong with spending $120? (1)

pfignaux (39568) | about a year ago | (#42141833)

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.

Re:what's wrong with spending $120? (4, Informative)

Zalbik (308903) | about a year ago | (#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.

Re:what's wrong with spending $120? (1)

toygeek (473120) | about a year ago | (#42143877)

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.

Re:Is a 7 Inch Swivel Blade Really Worth $30? (2)

semi-extrinsic (1997002) | about a year ago | (#42140755)

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.

Re:Is a 7 Inch Swivel Blade Really Worth $30? (2)

realityimpaired (1668397) | about a year ago | (#42140913)

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, which could be created by metal furniture nearby, or line of sight issues created by the household wiring (unless the antenna isn't attached properly, or is defective, both are possible). What you want is an outdoor antenna that can be mounted on the side of the house with a cable running inside. For that, I don't see anything on the page for less than $80, which puts it in the range where it's worth looking at building your own.

As to exactly how, there's other posts here which detail it, so I won't bother repeating them.

Re:Is a 7 Inch Swivel Blade Really Worth $30? (1)

Wovel (964431) | about a year ago | (#42141171)

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.

Re:Is a 7 Inch Swivel Blade Really Worth $30? (1)

Wovel (964431) | about a year ago | (#42141185)

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.

Re:Is a 7 Inch Swivel Blade Really Worth $30? (0)

Anonymous Coward | about a year ago | (#42141389)

I guess you get the response that a troll would get. e.g., you're a troll and you receive a trolls welcome.

Re:Is a 7 Inch Swivel Blade Really Worth $30? (0)

Anonymous Coward | about a year ago | (#42141417)

maybe it is not an antenna but a stronger signal you need. I havent tried this with 4g but for 3g it works you need a parabolic reflector (sat dish ) or what i used a curved photo frame covered in tin foil. put the antenna / device at the focal point and the dish will collect and transmit at a higher signal strength.
my 3g is marginal but with this simple cheap reflector $2 it is reliable. I might have gone for an external antenna but it wasnt an option with my devices

Re:Is a 7 Inch Swivel Blade Really Worth $30? (0)

Anonymous Coward | about a year ago | (#42141459)

Since quite a few have suggested a yagi, and LTE uses the old 700mhz TV range... how about a yagi sold for TV?

I use this yagi [amazon.com] for my TV. Worth a shot for $40? Others with better radio experience can say if this is a truly viable option.

You'll still need to fashion a connector to your cellular modem.

Re:Is a 7 Inch Swivel Blade Really Worth $30? (1)

PlusFiveTroll (754249) | about a year ago | (#42142237)

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 survived being outside in Texas weather without a glitch.

If you are doing an outside install of any antenna, use lightning protection. I have seen too many places stick a fixed wireless antenna outside, only to have it hit by lightning and have it come back thru the network port.

Re:30$? (1)

dj245 (732906) | about a year ago | (#42140715)

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.

Re:30$? (1)

egcagrac0 (1410377) | about a year ago | (#42141039)

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 direction where the tower is, and put it 7.75inches away from the antenna. Twiddle (err, tune the assembly) for maximum signal.

Re:30$? (1)

Marxist Hacker 42 (638312) | about a year ago | (#42141385)

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.

ARRL (5, Insightful)

Anonymous Coward | about a year ago | (#42140599)

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

Re:ARRL (1)

Anonymous Coward | about a year ago | (#42141393)

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.

Re:ARRL (1)

BrochesterL (2776475) | about a year ago | (#42143401)

I agree not only does the Amatuer Radio Relay League Offer solutions for these types of problem's but also you can find there reference at major city libraries that is just packed full of reference to everything from signal loss problem solving to transmitter schematics, It's the best option, and I am sure if you go to a fry's electronics there will be a rack backlogged with the monthly magazine "The ARRL antennea compendium" and no doubt one will contain a solution to a cellular band antenna troubleshooting situation.

Sounds like you need a WOKtenna! (2, Informative)

Anonymous Coward | about a year ago | (#42140605)

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

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

Make yourself a Yagi (0)

Anonymous Coward | about a year ago | (#42140607)


Or course the page is for Aussie 3G freq., but the links available will give you a starting point.

if the place is as boring as you imply, making your own will give you something to do :)


High frequencies = hard (4, Informative)

robot256 (1635039) | about a year ago | (#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.

Re:High frequencies = hard (1)

Svartalf (2997) | about a year ago | (#42140739)

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 a JetPack unit. The antenna access on little 5 device micro-routers like that can easily get damaged. Better off adding a small latency from the repeater to avoid damaging the JetPack in other ways since the connector is fragile and will eventually break off on them if they go the route described by the original post.

Re:High frequencies = hard (1)

indeterminator (1829904) | about a year ago | (#42140855)

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.

Re:High frequencies = hard (0)

Anonymous Coward | about a year ago | (#42141895)

The easiest to manufacture would be a corner reflector. It provides a reasonable degree of gain and dimensions aren't extremely critical, and overall size at the frequencies in question isn't an impediment. The ARRL has info on this, as well as other internet sites.

10 seconds of google research (4, Informative)

emmjayell (780191) | about a year ago | (#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]

Re:10 seconds of google research (5, Insightful)

Cornwallis (1188489) | about a year ago | (#42140679)

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

Here you go. [milkywaybar.com]

Re:10 seconds of google research (2, Funny)

Anonymous Coward | about a year ago | (#42140721)

that is sweet of you.

Re:10 seconds of google research (1)

the eric conspiracy (20178) | about a year ago | (#42141663)

I hear you. I used to live in upstate NY. Every clear night there it was. Most magnificent sight there is on this planet. It caused me to buy a 6" cadiotropic telescope.

Aurora Borealis once in a while too.

Now I live in NJ. I lost:

- Milky Way
- Aurora
- 140 inches of snow per year

Cantenna Waveguide (2)

StoneyMahoney (1488261) | about a year ago | (#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.

Antenna design (1)

Anonymous Coward | about a year ago | (#42140643)

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.

Classic is fine (0)

Anonymous Coward | about a year ago | (#42140651)

Just use a classic design for the carrier frequency your parents' system uses. That should be fine. New antenna designs for cell phones are driven by the need to fit in the handset.

LTE yagi (5, Informative)

HoaryCripple (187169) | about a year ago | (#42140675)

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

Decent instructions for an LTE yagi.

A note on grounding (1)

HoaryCripple (187169) | about a year ago | (#42140713)

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.

Re:A note on grounding (0)

Anonymous Coward | about a year ago | (#42141015)

You may be able to place it indoors.

Re:LTE yagi (0)

Anonymous Coward | about a year ago | (#42140883)

Bravo! Never say it can't be done. Lets hope it works as well as it looks. There is a lot of gain in that thar Yagi.

Re:LTE yagi (1)

Anonymous Coward | about a year ago | (#42140903)

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 :)

Re:LTE yagi (0)

Anonymous Coward | about a year ago | (#42141123)

Go through the trouble of building a Yagi and then weaken it with multiple adapters on the pigtail and the wrong type of coax. But I understand to keep it cheap.

If you are going to do this permanently, get a custom pigtail with the right terminations or put the correct termination on the right coax for the existing pigtail.

You could just... (5, Insightful)

Anonymous Coward | about a year ago | (#42140737)

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

Home Fusion?? (0)

Anonymous Coward | about a year ago | (#42140747)

Is there a reason they did not opt for Home Fusion? The rates are much lower and the directional antenna and transceiver is $100. I believe it also transmits at 3 watts instead of half-watt.


Line of sight is important. (2)

Gordonjcp (186804) | about a year ago | (#42140777)

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.

Re:Line of sight is important. (1)

rickb928 (945187) | about a year ago | (#42141055)

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

Re:Line of sight is important. (1)

Gordonjcp (186804) | about a year ago | (#42143107)

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 ;-)

Awesome question (0)

Anonymous Coward | about a year ago | (#42140781)

I don't have any information to help, just wanted to say this is an awesome question!

Finally something that's not "I can't do my job and am too cheap to hire a consultant" or "I don't know how to use google, please spoonfeed me".

I'm actually looking forward to some interesting answers (amongst the "just buy something" crap) even though I actually have no use for the information. This is what being a geek is all about :)

Best bet.... (0)

Anonymous Coward | about a year ago | (#42140787)

....is a corner reflector for an existing dipole antenna. The only critical
dimension is the spacing of the dipole from the corner, which can be
adjusted rather easily. I seem to recall that there are two sweet spots
with different patterns and gains. No cables or soldering, plus at
those frequencies you'll only need two or three sq ft of screen or

Verizon Home Fusion (1)

Anonymous Coward | about a year ago | (#42140947)

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:


Answer! (1)

nozzo (851371) | about a year ago | (#42140951)

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? (3, Informative)

Anonymous Coward | about a year ago | (#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.

Move the router? (1)

stiggle (649614) | about a year ago | (#42141117)

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.

Parabolic solution (0)

Anonymous Coward | about a year ago | (#42141133)

We have low signal at our cabin. I took an old satellite dish, duct taped the 3/4G modem at the focal point and aimed against the tower.
Worked perfect.. signal went from 10-15% to 40%.. way better speed and lower latency.

Re: Digital TV Antennas (3, Informative)

StatureOfLiberty (1333335) | about a year ago | (#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.

Log Periodic (1)

ctrl-alt-canc (977108) | about a year ago | (#42141271)

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.

Coax cable (1)

Maximum Prophet (716608) | about a year ago | (#42141303)

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.

Woktenna? (1)

Howard Beale (92386) | about a year ago | (#42141319)

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://www.usbwifi.orconhosting.net.nz/ [orconhosting.net.nz]

It's easy, use what the phone makers do- fractals (0)

Anonymous Coward | about a year ago | (#42141397)

It's easy, use what the phone makers do-> fractal antenna's

how do you thing they manage to get such good reception these days with 'built in' antennas?

they use a square form of this:
http://en.wikipedia.org/wiki/Sierpinski_triangle [wikipedia.org]

actually this:
http://en.wikipedia.org/wiki/Sierpinski_carpet [wikipedia.org]

thats it... the design is magic :) read about it seriously
perhaps use a 3d printer with copper based 'ink' or whatever

0 $ (0)

Anonymous Coward | about a year ago | (#42141423)

Google for "Cantenna". Works for WLAN, will work for UMTS. Believe me.

moD 3own (-1)

Anonymous Coward | about a year ago | (#42141527)

Talk to one of the Po7itics openly. progress. Any playing so it's are inherently the channel to sign formed his own [anti-slash.orOg] appeared...saying future at all

ANOTHER THOUGHT (2, Interesting)

Anonymous Coward | about a year ago | (#42141693)

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 antenna in the home, are there any other electronics radiating interference, like wireless dvd or bluetooth, for instance? Do their interruptions happen at certain times of the day (you can ascertain what other activities happen at that time of day that may be causing interference)? Do mom & pop have metal implanted in their bodies which may be bouncing the signals coming in? If they are receiving their signal to the house, wirelessly, and then also they are wireless between their router and the device they use to get information, that presents multiple points of potential failure. Is the placement of the router in the house near a window that faces the direction of the tower? Are they then on the other side of the house away from where the router is placed? Would a signal booster work on the side of the house where the user is located? cjacobs001

Ham radio (0)

Anonymous Coward | about a year ago | (#42141799)

Use the knowledge and experience of the local ham radio operators and build a simple dipole http://www.hamuniverse.com/dipivcal.html more than enough to receive from and more importantly transmit the signal back to the tower. Basically 2 pieces of wire at the right height of the right length and you are done.

Hear what? (0)

Anonymous Coward | about a year ago | (#42142051)

Although being able to hear the blood pulse through your ears

Dude that's not normal. Got see a doctor, you probably have high blood pressure.

4G or 4G LTE? (1)

raymorris (2726007) | about a year ago | (#42142231)

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.)

Re:4G or 4G LTE? (1)

wpsantennas-Mike (2785209) | about a year ago | (#42143019)

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)

Moxon Antenna (1)

Blackdognight (1329141) | about a year ago | (#42142265)

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 small you could get some copper clad from RShack and etch/scrape out the elements.

4G LTE antenna optioins (1)

wpsantennas-Mike (2785209) | about a year ago | (#42142309)

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---9dB.aspx [wpsantennas.com] is $120 but because of all of the questions from this blog I am lowering that down to $89 for the day. Once again any questions let me know.

Re:4G LTE antenna optioins (0)

Anonymous Coward | about a year ago | (#42143795)

Mike, *one* ad was enough. Although totally irrelevant to me due to location, I'm always happy to learn of shops that have answers, but most people on this forum can (a) read and (b) have a sufficiently long span of attention that they will spot you posting repeatedly. You're poking a vast nest of extremely spam-adverse wasps..

Antenna (0)

Anonymous Coward | about a year ago | (#42142311)

I do MMIC design, not antennas, but here's my opinion:

Build a massive parabolic reflector and put your existing antenna at the focal point. The focal point is the spot the reflector is focusing to. If you build it out of something shiny you can find this by pointing at the sun and finding the hot bit, this could be quite hot. Also be aware of wind as you're building a sail.

If you want to get fancy build a cantenna/rectangular horn and use that as the feed instead. (In a compound antenna the feed is the antenna that's doing the waveguide/free space conversion i.e cable in, raditation out)

Roughly, no matter how fancy a design you use, you cannot get out more power than passes through the area of the antenna. Therefore if you want a high gain antenna it has to be big. Reflectors are good as they're frequency independent and focus the radiation into a tight spot where you tap it out with another, smaller antenna.

There's a lot of information on google about these. Try searching for 'parabolic reflector' or 'heliostat' . The ARRL do good books, the microwave one is quite good and there's an antenna one, I haven't read it but its probably good. You can get an older edition if you want to save money.

http://www.amazon.com/The-Arrl-Microwave-Experimenters-Manual/dp/0872593126 [amazon.com]

http://www.amazon.com/ARRL-Antenna-Book-22nd-Softcover/dp/087259694X [amazon.com]

WTF is all this extra BS in the submission? (1)

Pope (17780) | about a year ago | (#42142329)

"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 5 or 6 sentences.

Re:WTF is all this extra BS in the submission? (0)

Anonymous Coward | about a year ago | (#42142431)

"...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.

If you had any technical knowledge at all, you would realize that he was letting us know that he knew which direction to point the antenna if someone suggested a unidirectional antenna. You appear to be so devoid of intelligence that you thought this was literary fluff ... try harder next time please.

So now you've built an antenna... (1)

Bartles (1198017) | about a year ago | (#42142645)

...how are you going to plug it into your phone? I'd like to know having a galaxy nexus and a shoddy signal.

Re:So now you've built an antenna... (1)

wpsantennas-Mike (2785209) | about a year ago | (#42142961)

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. Unfortunately most phones do not have antenna ports (some do but very few). For phones without ports there are 2 options a passive adapter http://www.wpsantennas.com/359914-passiveantennaadapter.aspx [wpsantennas.com] which will give you some signal gain but it likely won't be significant as it is passive and a powered amplifier booster which would very based on which carrier your service is thru

RF connector on the phone might be an issue. (1)

gmarsh (839707) | about a year ago | (#42142765)

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 10 cycles.

Don't build it yourself (2)

drwho (4190) | about a year ago | (#42142767)

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.

Your best bet... (-1)

Anonymous Coward | about a year ago | (#42143245)

Just fucking kill yourself.

Antennas on a printed circuit board (0)

Anonymous Coward | about a year ago | (#42143383)

Take a look at what this guy does with PC boards:


Dish it up (0)

Anonymous Coward | about a year ago | (#42143693)

If you can get your hands on a discarded/unwanted satellite dish, put any old outdoor or weatherproofed 4G antenna at the focus and point the dish at the tower. Never tried it, but in theory it should get you the amplitude you want.

Going To Try Old Dishnetwork Dishes (1)

DWDuck (181018) | about a year ago | (#42144065)

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 area to LTE and the little hotspot connects LTE - but with only one bar. It actually seems to work though.

The hotspot does appear to have two places to connect external antennas, but I'm almost positive they're for the Wireless-N router part - not for the LTE part.

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