My new Wireless Project

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10 years 8 months ago #35835 by Nunga
Ok, This is a run down on what i am about to do. I will be creating a Wireless link between my business and my property which is approximately 3km away.

The objective of this project is to connect the two building together and run the internet and phones through the wireless connection from my business to the house and cut the phone and internet off at the house. This will save me around $120 a month in phone and internet charges

If any of you have a shed or garage you were thinking of getting internet and phones to but they are to far away. You might find my project of use to you.

I will be using 2x 5GHz 150Mbps outdoor access points. They will be transmitting at 27dBi through a
5GHz 30dBi Outdoor Grid Parabolic Antenna on each end.

I am currently at Stage one. which is configuring them to run in Bridge mode and testing connection speeds locally at home.

Over the weekend I will be mounting the Antennas to the roof of my business, and at the house end i have decided to mount that to a large pine tree we have on our fence line. This will give me direct line of sight.

I can also transmit power to these units up to 100 meters through my wireless POE transmitter so there is no need to run power or any cables to the units.

I will be posting photos of the stages and keep you updated on my progress and any problems i may run into on the way.

Watch this space!

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10 years 8 months ago #468854 by Jen - Featherston
interesting will be keen to see how you get on and a total cost for completing the project - good luck!

Sometimes its not only what you say, its the way you say it that counts.

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10 years 8 months ago #468937 by suckerpunchnz
I'll be reading with great interest too!
Please post up equipment make and models and where you purchased them from.

Hope the weather stays fine for you this weekend.

Thanks!
Phil.

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10 years 8 months ago #468971 by Nunga
Replied by Nunga on topic My new Wireless Project
Here is the first Grid Parabolic Antenna installed. I think the weather will be crap so i made a start on it today.

@ suckerpunchnz

I have used TP-Link gear for this project.

The access point is a TL-WA7510N
The Grid Parabolic Antenna is a TL-ANT5830B

Got everything form PB Technologies in Penrose

Cost is around $700 for both ends which includes antenna cables

Attached files
File Attachment:

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10 years 8 months ago #468978 by Hawkspur
Replied by Hawkspur on topic My new Wireless Project
Interesting to see how this goes for you: I have suggested a slightly similar set up for a client who needs broadband and has line of sight to a friend's house (where they have broadband because near a rural school) ~10km away.

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10 years 8 months ago #468979 by Nunga
Replied by Nunga on topic My new Wireless Project
10k is probably pushing it with this gear. 5Ghz is not really the best solution for long range transmitting even tho they say this setup can do up to 50k line of site.

I used it because there is less traffic broadcasting on that frequency.

The general rule of thumb is the lower the frequency the more distance and penetration you will get. 2.4Ghz would be better but everyone uses it.

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10 years 8 months ago #469017 by spark
Replied by spark on topic My new Wireless Project
Hi,

I've had a bit of experience with wireless networking.

One problem that I have seen with some 5.8 GHz point to point link units, is that, out of the box, they are configured automatically use any available frequency from about 5.2 to 5.9 GHz - this is a problem as operation outside of the correct NZ "licence free" band is strictly speaking radio piracy [}:)] (and Radio Spectrum Management/Ministry of Economic Developement take a dim view of it...). It is normally very easy to configure wireless bridge units to stay within the correct band.

The band that will be of interest for your application is 5725 to 5825 MHz, where you are allowed to transmit at up to 200 Watts EIRP for a point to point link.

You said that your transmit power was 27 dBi? did you mean 27 dBm? (27 dBm is 0.5 Watts or 500mW of transmit power). A 30 dBi dish will give you 1000 times gain, which not allowing for cable losses, results in a rather illegal transmit EIRP of 500 Watts (which sounds rather excessive for a 3km link). Your wireless network bridge should have an option in the configuration where you can adjust the transmit power level down to a lower level.

If you know your receiver sensitivity, antenna gains, cable losses, etc you can do a path loss calculation and work out exactly what transmit power level you need to get a good fade margin. (I am quite happy to explain the maths to anyone who is interested).

I have found that where you have good line of sight (as in nothing but air in the way, and clear "fresnel zones") that 5.8 GHz works really well, even over long distances. Generally lower frequency signals like 2.4 GHz and 900 MHz are more penetrating of obstructions like trees and buildings, but at lower frequencies antennae are less efficient (you need a bigger dish to get the same gain) and the legal transmit power limit is only 4 Watts EIRP on 2.4 GHz and 900 MHz.

This website has a good tool for plotting the elevation path and fresnel zone for a proposed radio link between two points (it does not account for trees and vegetation though):
www.geocontext.org/publ/2010/04/profiler/en/
(make sure plot mode is "scientific", "Linear" check box ticked, "A-B" checkbox ticked and "Fresnel" checkbox ticked. Set your radio frequency and the height above ground of the antennae at each end of the link. If it is a long link, then make sure that "curved earth" checkbox is also ticked)

Cheers

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10 years 8 months ago #469030 by Nunga
Replied by Nunga on topic My new Wireless Project
Thanks for your feed back... I did do a LOT of research before i parted with my hard earned cash, and now you have put a spanner in the works lol

It is impossible for this setup to transmitting at 500Watts??, For one it is illegal. Two, the dish has a max power output of 100Watts and Three, Surely my suppliers should not be aloud to sell gear that is not legal in New Zealand.

Im not sure who is right and who is wrong now, I am getting very confused reading all this, on the one hand you seem to know what you are talking about with your math and have given a good example, But on the other hand the manufactures specifications are telling me something completely different.

www.pbtech.co.nz/index.php?z=p&p=NETTPL5...-Outdoor-Grid-Parabo

I am going to go over everything again tomorrow and double check all the gear and settings and check my math. But for now time for bed as it is 2am and i need some beauty sleep :)

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10 years 8 months ago #469033 by Aquila
Replied by Aquila on topic My new Wireless Project
Lots of people sell things that can be used illegally but its not their problem how you use it

Sent from my GT-I9300 using Tapatalk 2

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10 years 8 months ago #469035 by Nunga
Replied by Nunga on topic My new Wireless Project
Just checked and yes you are correct it is 27Dbm not Dbi.

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10 years 8 months ago #469084 by spark
Replied by spark on topic My new Wireless Project
Hi,

Nunga;471485 wrote: It is impossible for this setup to transmitting at 500Watts??, For one it is illegal. Two, the dish has a max power output of 100Watts and Three, Surely my suppliers should not be aloud to sell gear that is not legal in New Zealand.

www.pbtech.co.nz/index.php?z=p&p=NETTPL5...-Outdoor-Grid-Parabo

I understand that NZ Customs main focus is biosecurity, drugs and weapons - they are pretty hopeless when it comes to non-compliant electrical equipment...

According to that link, the 100W rating of that dish is maximum input power - if you try to feed more than 100W into that dish you will likely cause it to fail either due to overheating or insulation failure.

That dish produces 30 dBi or 1000x times gain compared to an isotropic radiator (one that radiates equally in all directions). The basic way to explain this is that the dish focuses the radio waves into a narrow beam (like light from a searchlight), and that whatever the dish is pointed at, receives a signal that is 30 dB stronger than the signal that would be received if an isotropic radiator was used instead of the dish.

Your transmitter produces a transmit power of 27 dBm or 0.5W, if you connected this to an isotropic radiating antenna, you would have an EIRP (Effective Isotropic Radiated Power) of 27dBm. However, when you connect that transmitter into a 30 dBi dish, it focuses the signal into a narrow beam, and the EIRP becomes 27 dBm + 30 dBi = 57 dBm or 27 dBW or 500W (which is well and trully illegal). Effectively, as far as wherever the dish is pointed is concerned, the signal will be as strong as if you had a 500W transmitter connected to an isotropic radiator.

To run your link flat-out at 150mbps, your receiver probably wants to see about -75dBm signal strength, allowing for a 30dBm fade margin (so your link doesn't slow down or stop working when it rains, or snows, or fog sets in), you want -45dBm signal strength at your reciever. 3 km of air at 5.8 GHz has a pathloss of about 117 dB and you have a 30dBi gain antenna at each end of the link (60 dB gain).
So, -45dBm (rx signal) - 60dB (antenna gain) + 117dB (pathloss) = 12dBm (about 0.016 Watts) transmitter output power required to be fed into the dish.

Cheers

License conditions for 5725 to 5785 MHz:
Licensee
137373 EVERY PERSON
Licence ID 101846 Other / Miscellaneous

Specific Conditions

Any person may transmit radio waves using radiocommunication transmitters, including those known as U-NII devices, for the purpose of fixed point-to-point communications using digital modulation techniques to typically provide high data rates, in accordance with the terms, conditions and restrictions of this licence.

General conditions applying to all transmissions under this licence

1. Transmitters must conform to radio standards as prescribed in notices made under Regulation 32 (1) (b) of the Radiocommunications Regulations 2001.

2. Frequency use is on a shared basis and the chief executive does not accept liability under any circumstances for any loss or damage of any kind occasioned by the unavailability of frequencies or interference to reception.

3. Should interference occur to services licensed pursuant to a radio licence or a spectrum licence, the chief executive reserves the right to require and ensure that any transmission pursuant to this licence change frequency, reduce power, or cease operation.

4. Notwithstanding the provisions of this licence, the radiated power must not exceed that necessary to reliably maintain communications.


5. Point-to-multipoint systems, omni-directional applications, and multiple co-located transmitters transmitting the same information are not permitted.

6. All transmitters must employ digital modulation techniques.

7. The permitted peak transmitter power is 0 dBW (1 W).

8. The permitted peak power spectral density shall be less than -13 dBW/MHz (50 mW/MHz).

9. The permitted peak radiated power is 23 dBW (200 W) e.i.r.p.

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10 years 8 months ago #469106 by Nunga
Replied by Nunga on topic My new Wireless Project
Again thanks for the info. I have used a online calculator to work out my power. I have changed to 23DBm which will give me 126 Watts of power. (this includes 2 db Cable Loss)

www.wifinerd.com/wifi-calculators.html

Cheers.

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10 years 8 months ago #469111 by Alan Gilbert
Something else to watch out for with any home-installed gear like this is that you site the antennas high enough that there is no possibility of any person's coming into their direct line of fire within a close distance.
Radio waves are perfectly safe as long as they strike a human body at a low enough intensity not to cause any heating of tissue. The level at which such heating does occur varies with frequency and power density (which latter in turn varies as the radiated power and the inverse square of the distance).
Off the top of my head I can't tell you the safe distance from your antenna, but at your power and frequency it's likely to be of the order of several metres – as a "rule-of-thumb" guess, if it were me, I'd make sure no-one could look directly into the antenna from less than twenty metres away.
Incidentally, the inverse-square-law-of-distance thing explains why using a cellphone held close to the head for long periods is a really dumb idea. Although the power level is quite low, the distance is effectively zero, and the power density is therefore surprisingly high. The worst offenders in this regard are often the same people who campaign vigorously against having a cellphone tower within cooee, people who wouldn't know an inverse square law if it stood up and bit them on the bum.

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10 years 8 months ago #469112 by Nunga
Replied by Nunga on topic My new Wireless Project
The house install will be aprox 30mtrs up a pine tree, and the other end is on top of a 2 story building and the mast is another 3 meters above that so unless superman happens to fly past i think it should be pretty save and he is the man of steel anyway :).

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10 years 8 months ago #469125 by Short Plank
Replied by Short Plank on topic My new Wireless Project
Hi. I helped set up, and am chief technical guru for a non-profit community wireless network set up six years ago when it became obvious none of the commercial guys were interested in providing for our locality, leaving us nothing bar satellite or dial-up at 2.5 kbps downhill on a good day. We've around 30-subscribers now, paying about $4/GB/month at up to 10MBps up and down. Your gear, Nunga, is way over the top - our main backhaul to the radio tower of a wireless ISP which feeds us into town fibre is over 17km at 5GHz and it works perfectly well with a 400mW wireless card and a 24dB parabolic antenna. You could probably do 3km these days with a couple of $45 D-Link/Cisco/Belkin etc. wireless routers. If you haven't bought the gear yet we could do the whole thing for less than the cost of one 5GHz 30dB antenna, but if you've got it already post here or pm me if you have any problems. Two thoughts - for a private network where you won't have ISP speed limits anyway you might as well go as fast as you can, which means the 'n' protocol. And as you're going to be broadcasting over all your neighbours to the horizon with the gear described above, you'll need privacy and security.

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