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Ask Slashdot: DIY 4G Antenna Design For the Holidays?
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?"
Something like this costs 30$
http://www.wpsantennas.com/700MHZ-LTE-4G-Antennas.aspx
Ebay has things for 20-25$
Did you look at these options before deciding to building your own?
My Aurora : http://www.youtube.com/watch?v=o91ZsGwJYyg
FB : https://www.facebook.com/TanveersPhotography
Start with ARRL (http://www.arrl.org/)
Antenna Handbook: http://www.amazon.com/dp/087259694X/
*The* Handbook: www.amazon.com/dp/087259419X/
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 $300 once). Otherwise, just making random things could result in reflections damaging your transmitter. This isn't like putting together a 1/4-wave dipole on 2 meters.
But you could try fashioning a parabolic reflector dish and put your existing antenna in the center of it. I've heard of people doing that with cell phones and wi-fi adapters before.
How about posting some pictures of the milky way? I've only barely seen it once while on Hilton Head island.
http://www.dslreports.com/forum/r27484816-DIY-3G-4G-LTE-Yagi
http://bcbj.org/antennae/lte_yagi_diy.htm
Something like this costs 30$ http://www.wpsantennas.com/700MHZ-LTE-4G-Antennas.aspx
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 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.
My work here is dung.
http://bcbj.org/antennae/lte_yagi_diy.htm
Decent instructions for an LTE yagi.
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.
Damn_registrars has no butt-hole. Damn_registrars has no use for a butt-hole.
scrap the tons of copper and steel you have, then buy an antenna.
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.
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/#
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
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
I also built a folded dipole for VHF: Here is an example:
http://crdahl.com/antennas/dipole.html
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.