Has any one added an amplifier to a broadband (verizon fios ) box? - Page 1
Forum section: electronics / rf-microwave

author: Beamin
author_rank: Super Contributor
timestamp: October 25, 2017, 02:56:16 am
content: I bought a 60db gain amplifier to try and get more range out of my broad band.Inside from (internet pictures I'm waiting on an extra box to come that I can mess up) what I can tell there are three antennas. Each one is identical in size and has the same length thin coax to it.These are 5ghz and 2.4 ghz units with internal antennas. Two antennas are parallel third is perpendicular. They look like little folded dipoles but with one conductor.Would that mean they are using two as a 2.4 ghz dipole and the third for 5ghz?And do these little amplifiers allow RX to come back through the amp to the radio? I can't find any info on how these work. Such as does the router unit transmit and receive on at the same time a few MHz apart or does it pulse back and fourth? Would I need a transmit and receive antenna and use pin diodes network to quickly switch between the tx and rx antenna?If I can figure this out I'm putting a little full wave length yagi on it. I want it a bit like a cell phone/tower set up: Where the tower puts out a stong signal and has a very high db gain receive antenna to make up for low power laptop wifi.The amp is the standard 12.00$ "2.4"GHz amplifer they sell on ebay.The sicker on the front says1m-2Ghz (not 2.4 but every advertisement says 2.4ghz)12V64dbI=70maIT has two sma jacks 12 volt input term. and most of the parts are in a metal can on a PCB with a metal back plane.I have seen some serious range from wifi with the proper antenna and just a little bit of power. Would be rally cool to set up a link with a directional antenna channel to an obscure channel as not to interfere with other devices (most are set to 11 or will change the channel when there is interference). If I can get wifi into an uninhabited field surrounded by wood that would be perfect.

author: Beamin
author_rank: Super Contributor
timestamp: October 25, 2017, 03:12:23 am
content: And since people will remind me here is the law regarding the ISM band:Quote

author: Mjolinor
author_rank: Frequent Contributor
timestamp: October 25, 2017, 06:43:05 am
content: Unless you stick an amp at both ends you will not gain much. A far better solution is to buy high gain antennas and use the A band at 5 GHz.With standard spec. outputs and two Yagis or patch antennas (15 db gain or so, one either end) twenty miles is easy and will give you around 25 mbits.

author: Kire Pûdsje
author_rank: Regular Contributor
timestamp: October 25, 2017, 06:25:49 pm
content: Amplifier gain will not really help you.On the receive side, despite popular belief, the LNA gain should be as low as possible.The gain should be sufficient to hide the noise of the receiver, so that the system noise will be dominated by the LNA noise figure. Any more gain will not result in better performance. It will be detrimental, since it can only generate intermods.For example when adding a long cable between the antenna and the receiver, with say 10 dB loss, a 15 dB gain amplifier will suffice.On the transmit side, the output power of your unit will most likely already be in the 20 dBm range, you will need to add some real power amplifier to be able to boost that one.As advise by Mjolinor, a yagi at both ends will really boost the link. A 60 dB amplifier on the receive side will in practice only result in maybe a 2 dB better SNR (corresponding to a 1.1x increase in range). A 15 dBi gain antenna at both sides will improve your SNR by 30 dB (corresponding to a theoretical 30x increase in range)Edit: Sorry this assumes your antenna was 0 dBi. Most likely it will be roughly 3 dBi, so with 15 dBi, the improvement is 2*(15-3)=24 (corresponding to 16x increase in range)

author: radiogeek381
author_rank: Regular Contributor
timestamp: October 26, 2017, 01:40:10 am
content: Quote from: Beamin on October 25, 2017, 03:12:23 amMr. Beamin,I've read big hunks of Title 47 CFR (parts 97 and others) and never come across the use of the second person pronoun. Wherever you got this, you were ill served. It is certainly not "the law".If you are serious about "doing the right thing" then take a look at Title 47, Part 47 athttps://www.ecfr.gov/cgi-bin/text-idx?SID=781d0aac581385a7e8f977d0632633d5&mc=true&node=pt47.5.97&rgn=div5If you are going to treat this as an amateur transmission, you'll need to provide a CW id or some other approved method of identification at intervals not to exceed 10 minutes. (97.119) You'll need to ensure that the material is not music, or retransmission of any of a number of types of material. (97.113) Treating this as a message forwarding system is a tight fit for section 97.219.I can also recommend the fascinating reading in parts 15 and 18. Given that the ham ticket is not a "get out of jail free" license to chunks of the spectrum, part 18 lays out some very clear restrictions on effective radiated power, antenna gain, and a host of other things.You didn't mention using a power amplifier on transmit. That's good, because Part 97.313,315, and 317 are very very clear on this one. Your ham ticket does not permit such use in the 13cm band if the amplifier has more than 15dB of gain, or if it lacks FCC type acceptance and was purchased after April 28, 1978, unless it was built by a ham, and even then there are requirements. (You are responsible for ensuring that it is well behaved. Measuring this takes judgement and possibly some equipment that you don't have. (A spectrum analyzer isn't sufficient here.))If that yagi you're thinking of using is in the TX chain, then you're going to have trouble with Part 18.You're pretty smart. You ask a lot of questions. You are investing time in this. There are far better ways to learn than to copy crap antennas from the web and buy quack preamps from fleabay. (Anybody who sells a "60dB" preamp that goes from "1m-2GHz" is not looking for return customers.) If you really want to do something interesting that will get you lots of experience, build a preamp for 2 meters. Or build a QRP power amplifier for one of the HF bands. Or build a microwave transverter, if you really want to do stuff in the 2.4 GHz band. Your idea of building a modular AM transmitter was really good, just keep it to the spectrum you are licensed for.Build or buy one of those DC to daylight preamplifiers and put it in front of a receiver. Listen to the signals. (There are likely a few beacons near you on 2m that you should be able to hear with even a modest antenna. I hear several from a discone in my attic.) Then experiment -- add some filtering ahead of the amplifier. Back off on the gain. Add a pad before or after the antenna. Build an actual amplifier that really does have 60dB of gain and figure out what frequencies it is oscillating on. (That's why a few of your readers view the advertised claims of 60dB gain as improbable.)The time you can spend learning useful stuff is far too valuable for this kind of silly experiment.

author: timb
author_rank: Super Contributor
timestamp: October 26, 2017, 03:07:42 am
content: Quote from: Beamin on October 25, 2017, 02:56:16 amThe technology is called MIMO (Multiple Input Multiple Output). Essentially the router transmits simultaneously over multiple antennas. The WiFi controller dynamically tunes the transmit power of each antenna, to minimize multipath distortion, interference and so on.The internal antennas are “universal”, in that they’re tuned for the best range at both 2.4GHz *and* 5GHz.I’d recommend you buy a standalone WiFi router (you can disable the router functions and use it as just an access point) that already has external antennas, instead of trying to retrofit your Fios router. Unless you really know what you’re doing, trying to bodge in external antennas is very likely to make the performance worse or break something.If you’re in an area with a lot of 2.4Ghz networks, you’ll be better off buying a new access point with external antennas and setting it to 5GHz only. (You’d disable the WiFi functions of the FiOS router in that case.)Alternatively, you could set the FiOS router to 5GHz only and then install several 5GHz repeaters around your house.If you need a point to point link over a long distance, line of site, your best bet is, again, buy a new router with removable external antenna, install third party firmware (OpenWRT, etc.), disable the router functions (access point mode only), disable the MIMO functions (so it only uses a single antenna) and hook a 5GHz YAGI antenna up to it.I’ve seen a $30 router running OpenWRT do close to a mile line of site, on 5GHz with no external amp (250mW TX power).Several miles can be achieved with a 1W booster, but you start running into other issues and your speed will be limited.(Actually, I’ve got a WiFi controlled quadcopter that can do about 1/2 mile via a special controller that’s essentially a WiFi router hooked to a directional antenna; others have gotten several miles with a power booster, under the right conditions, though it’s a one way trip due to battery power.)

author: Beamin
author_rank: Super Contributor
timestamp: October 26, 2017, 04:48:04 pm
content: Quote from: timb on October 26, 2017, 03:07:42 amSo basically go with the pineapple thing that they talk about on "HAK5" where they show you how to make a long range wifi tuner then tell you how to detune it undoing almost all the work you put into it to make it comply with the law. I guess they don't want to get sued or some other bullshit on a show called "HACK". The whole idea of hacking is operating on the fringes of laws and norms, not following all the rules to a "T". That's not hacking; that's using things the way they are intended.I guess when it comes to Linux and software I find that aspect tedious vs the hardware which is fun to build. I use lap tops and other things and the goal is not to have to chop open the end devices. Make it like a cell phone where the tower does all the work. I really just want to be able to use the internet out in the woods far from my house. I chose 2.4 GHz because 5Ghz seems to suck at going through things like trees and walls. Also 5Ghz is lot less forgiving when measuring antennas and making sure your cables are not part of the antenna. 900 MHz is really best but that's not how things were built.And for the people that told me about the laws thank you: Its always good to know the laws before breaking them. In my mind laws are suggestions you should follow and nothing more. For every rule there is an exception. Keep in mind laws are written for the lowest common denominator: people too stupid or too selfish to do the right thing. That's not me and if I don't cause disruption then no harm no foul. I usually do my homework to make sure if rule bending goes on that there are no negative consequences from it. If you live 100 miles out in the desert and want an illegal 40 mile wifi that no one will ever see or hear then go for it. If a development goes up within range be prepared to tune down. You won't get far in life following every norm and rule perfectly avoiding risks. That's just my 0.02$ and no law can be written to change that and if they do write one I will find and exception and a loop hole. Worst case scenario they will ask you to turn it off or even pay a fine but highly unlikely if you did your risk assessment right.So a real DIY solution is not really viable. Best case is buy a high gain antenna and wifi extender and mess with the software to get maximum power/range out of it. Glad I read about MIMO I would never have figured that out on my own and really makes modifying the wifi box undoable.