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I'd like to install a wireless ip camera near the back of my property. It will be several hundred feet into some woods. I plan on using some large directional antennas to help me get the range I need. Is 5ghz or 2.4ghz better at penetrating the trees and leaves?

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Trying to catch an image of Slenderman? You might looking at directional wifi antennae, as you don't need a large area covered. – SaintWacko Sep 14 '12 at 17:00
    
Can you put an antenna up high in one of the trees? There may be less stuff blocking the signal path up there. – martineau Sep 14 '12 at 17:49
    
This is a possibility I'm looking at. – Cody C Sep 14 '12 at 17:52
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According to my neighbors, the longer the wavelength the more penetrating. ;) – Louis Apr 13 '13 at 23:58

How is the camera getting power? If it is mains, you may want to look at buying a pair of 'Ethernet over powerline' adapters. They are cheap, allow you to use your mains wiring like a network cable, and I have found them to be a lot more reliable than wifi.

I believe that lower frequencies have better range and ability to get passed obstacles. From my own experience of having a dual band router, the 2.4ghz has a far better range than the 5ghz signal.

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This is what I would do. Easiest solution and makes transmission through the trees a moot point. – Lee Harrison Sep 14 '12 at 16:56
    
You might have trouble with signals getting back with just battery power and trees in the way. If there is no direct line of sight, you may be able to go up, and get both antennas above the tree line. – WhoIsRich Sep 14 '12 at 17:58
    
@CodyC if you're unable to get wifi working over that distance ethernet over coaxial boxes are available with more than sufficient range for your application. For ex StarTech EOC110R adapters with a 2.4km range can be found for ~$125 each (selected via google search, I've never used them). There're less expensive adapters available intended for running a network over existing coax runs; but I couldn't find max cable length data for them. – Dan Neely Sep 14 '12 at 20:56

Typically, higher frequencies have better penetration through solid objects, but have shorter range than lower frequencies.

I would suggest getting devices that support both, so that you can play with the settings.

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I think you've got this backwards based on WhoIsRich's answer and what everything else I've read. I wasn't sure if it was exactly the same for trees/leaves though so that is why I asked. – Cody C Sep 14 '12 at 17:41
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No it is correct, do some googling and you will see. – Keltari Sep 14 '12 at 17:46
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I did, and everything says lower frequencies penetrate better. – Cody C Sep 14 '12 at 17:51
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@Keltari - Can you provide any evidence. I agree with CodyC that lower frequencies penetrate better en.wikipedia.org/wiki/IEEE_802.11 & en.wikipedia.org/wiki/Line-of-sight_propagation – user3357963 Sep 14 '12 at 22:05
    

The lower the frequency the better the penetration (Ignoring super high frequencies like X-RAY). Thus a 2.4 gig connection will be better then a 5 gig connection - although neither will be particularly good. If you don't need a lot of bandwidth, try something on 900 MHZ or even lower if you can get the gear.

(An extreme example, I believe submarines use extremely low frequencies for communication. This limits there bandwidth, but gives them a large range through water. Whales do the same thing).

If you are trying to use "off-the-shelf" 2.4 gig gear, look into gear with MIMO (multiple antennas). The trees are going to provide a lot of reflections, and using MIMO gear you may be able to filter some of it out - although a lot of it will be absorbed - particularly by the water content in the trees.

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Several hundred feet sounds a bit far and demanding (really depending on how the actual location is, how much foliage, etc.).

I'd go with a dual band solution, but 5 GHz 2.4 GHz would most likely offer the more stable connection. If possible, you might get even better results using some repeater inbetween, but it's really hard to guess not knowing what's the location like (some small house in the garden or woods, door entrance, etc.). In general however, I'd suggest you use a camera with a cable (maybe even combined with a WiFi bridge to cover some problematic area (like a road or river) if possible.

Also keep in mind that directional antennas aren't allowed to be used everywhere. If in doubt, check with your local authorities.

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Lower frequencies (like 900mhz) are the best for dealing with obstructions like trees. Big things, like buildings with lots of metals in them, or the earth itself, can completely prevent even the best directional radios.

The signal spreads out from the point of origin and contracts again at the destination (visualize a sort of elongated football), and does so more exaggeratedly for lower frequencies. But this extra spreading (and longer wavelength) allows the signal to diffuse around obstacles (or pass through), like trees or houses.

5 Ghz or higher is best for long range where direct line of sight is possible because the beam is much tighter, but if there are obstacles, you will see loss quickly. 2.4 Ghz is pretty good at penetrating obstacles and can still do distance well enough, but everyone and their mother (almost literally) has a 2.4 Ghz access point attempting to shout louder than the others, so interference is likely. 900 Mhz does penetrative performance better than the others, but requires more gain to go the same distance as 5 Ghz, if line of sight is established.

Sources:

https://wiki.ubnt.com/Selecting_airmax_product#The_2.4_vs._5.8_dilemma https://wiki.ubnt.com/Getting_Started_with_airMAX

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Of "easily available, off the shelf" gear, 900 MHz is the choice for woods-fi. Rather expensive in comparison to 2.4 & 5 GHz gear, but if anything (other than a chainsaw) is going to punch through trees, that will be the one. If the camera connects only by WiFi you'll need a 2.4 or 5 GHz access point at the end of a 900 MHz point to point link. If it has an ethernet port, you can just plug it into the 900 MHz radio at that end. A decade or more back I had a super-duper 900 MHz phone that would go 1/2 mile through trees, so long as it was only trees, not dirt (it didn't go through dirt, so a hill in the way meant it didn't work.)

The chainsaw might make a good deal of sense, depending. If you can open up a clear line of sight (including at least 60% of the "Fresnel zone", basically a cigar-shaped space that's pointy at your antennas and fat in the middle), 5 GHz stuff works dandy, and is a LOT cheaper (and smaller) than 900 MHz. For "a few hundred feet" at 5 GHz, the Fresnel zone is only 8-10 feet in diameter at the fattest. Here's a calculator (just one I found, no affiliation, you'll have to express the distance in fractional miles.)

http://www.proxim.com/products/knowledge-center/calculations/calculations-fresnel-clearance-zone#feet

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Lots of bad physics in the above. You have to separate the concepts of penetration (e.g. passing through solid objects) and diffraction. Lower frequencies will have more range/penetration within solid objects - water is best thought of as solid in this context - this explains the whales and sonar touched upon above.

However, lower frequencies (really it's their longer wavelength that's responsible but there is an inverse relation between the two) also duffract - or spread out around - obstacles better. This is most of the reason long wave radio can be picked up over much further differences.

So within one media eg water longer wavelength/ lower frequency is more penetrating and there is an 'obstacle avoiding' (as opposed to penetrating) aspect to lower frequencies too.

However, in most cases, were not interested in the sea/water analogy because we want our signal not to continue indefinteky through one uniform media - but to go around corners, pass from air into a door and out again etc. This is a dufferet kettle of fish altogether. Because of this, the water /whale/sonar penetration aspect is not the prime factor by far. It is the diffraction that's the more relevant physical effect.

For best diffraction, you want a wavelength comparable with the obstacle you're trying to avoid. A door or tree for that matter is around a metre across. This corresponds to a similar wavelength and a frequency of around 300 MHz or 0.3 GHz. So you can see how far away from this ideal the available frequencies are. Thankfully, diffraction depletes for a higher wavelength than the obstacle; for much lower it disappears.

The other aspect is a different kind of penetration. Normally if a radio wave passes from air into eg a wall or other media the effect is that it's attenuated and it's direction is changed. If you start shifting to much higher frequencies, you reduce this eggectm in fact, someone mentioned x-rays - at higher and higher frequencies the energy becomes more particle like - high energy penetrating particles like x Ray photons. You've lost all the benfucual diffraction effects (as just mentioned if you think about it) and it's much more a line of sight affair. But it starts to get more penetrating in the sense it will pass from air to tree trunk and out again without much deviation. 60GHz WiFi works a bit more like this - more truly penetrating - though without losing all the beneficial diffractionness at that frequency.

Ps the poster above correctly identifies that 900MHz will get through the trees (because of diffraction) but is mistaken rre:.the dirt comment - it won't get round hills because of the size of a hill - a lower wavelength like normal lw rf would do that. The 900M isn't penetrating the trees it's diffractibg - so the penetration into dirt is nowt to do with it.

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