This antenna will give you 24 dbi gain (for the barn end). http://compare.ebay.ca/like/200771492500?var=lv<yp=AllFixedPriceItemTypes&var=sbar&_lwgsi=y&cbt=y&lpid=33&item_id=200771492500
This antenna will give you 12 dBi gain (for the house end). http://www.ebay.ca/itm/TP-Link-Network-TL-ANT2412D-2-4GHz-12dBi-Outdoor-Omni-directional-Antenna-/360694522161?_trksid=p3284.m263&_trkparms=algo%3DSI%26its%3DI%26itu%3DUCI%252BRTU%26otn%3D21%26pmod%3D200771492500%26ps%3D54 Using one highly directional antenna and one omni will also solve your hidden node problem. This simple slide deck has 2 important numbers for you: http://www.mouser.com/pdfdocs/Site_Surveys_for_Wireless_Networks.pdf 1) The dBi loss formula for free space transmission is 36.56 + 20Log10(2400000000) + 20Log10(0.062). You are going to loose approx 83 dBi of signal strength at 150m. 2) The freznel zone clearance radius for transmission is (i can't type it with out a math font... but look at slide 6). for 150m, it's approx 9 feet. If your base radio transmission power is 21 dBm (assuming you have DIR-615 c2's) and you stick a 12 dBi omni at your house and a 24 dBi directional dish at your barn, you will have (21+12 = 33 dBi transmit = approx 2Watts (1995mw)) at your house and 21+24=45 dBi transmit = 34 Watts. Yes... 34 watts. This is a staggeringly illegal transmit power. You'd have to turn down the power on your radio in the barn to about 12 dBm (approx 15.8 watts), or get a directional dish with lower than 24 dBi gain. The result is that you can *EASILY* hit your legal transmission limits without any amplifiers. if you have (33 + 36) = 69 dBm gain on your link... and 83 loss from the distance of 150m. This means your effective rssi should be approx (69 - 83) = -14. Now, assuming you need to put some cable between your DIR-615's and your antennas (so they can be housed indoors or at least not in the snow), i'll add to this 5 meters of LMR400 cable with connectors to each end: http://www.timesmicrowave.com/calculator/?productId=52&frequency=2400&runLength=15&mode=calculate#form so you will lose 1 dBm for antenna cable distance (per end) and 1.2 dBm for the assemblies (per end) so, -14 and -4.4 = -18.4. For a frame of reference... -18.4 is still an AMAZING signal level... [image: Inline image 1] On Tue, Sep 17, 2013 at 9:41 AM, chris kluka <[email protected]> wrote: > Also, for 150m, you don't need 2 directional antennas. > > You could get a single omni antenna at your house and a single parabolic > grid antenna at the barn. You probably don't even need amplifiers. > > Source: I built the wireless deployment at the blue bomber stadium. > > > On Tue, Sep 17, 2013 at 9:39 AM, Rob Guderian <[email protected]>wrote: > >> Neat. I have a wrt54g in my garage right now (as a prototype project). >> I was going to leave it there, but might have to repurpose it. >> >> On Tue, Sep 17, 2013 at 9:32 AM, Adrian Stoness <[email protected]> >> wrote: >> > the wrt54g's seem to handle the cold prity good had one going in -40 >> temps >> > for a while with no heating >> > >> > >> > >> > On Tue, Sep 17, 2013 at 9:22 AM, Rob Guderian <[email protected]> >> > wrote: >> >> >> >> Yeah, I'm talking outdoors, but not extreme distance. I could throw >> >> money at this project, but origin of the project was to build a >> >> cantenna - I just needed an application for it to motivate myself. I'm >> >> also choosing to to this on the cheap as part of the challenge. >> >> Reliability/throughput is ... not a huge deal - I don't exactly have >> >> clients waiting on me. >> >> >> >> Somewhat better breakdown of the problem domain: >> >> Farmyard. Main house, 2 outlying buildings that are about 100-150m out >> >> from the house. Both have south-facing windows I can use to warm an >> >> area to consumer-grade hardware levels using both a greenhouse effect, >> >> or with some kind of heater if required. >> >> >> >> So, stage 1 is get wireless to the outlying buildings. Stage 2 is to >> >> install sensors indoors, and outdoors. I'll probably go with Raspberry >> >> pis - and have them report back with images, humidity, temperature, >> >> etcetcetc. But that's longer term, and will grow organically. >> >> >> >> >Note the 2 antennas are on the same "radio" / in the same collision >> >> > domain so you can't point them to different places or use them as >> separate >> >> > "networks". >> >> >> >> That's true. I'm planning on keeping them on the same network, and it >> >> will cause a hidden node problem at the hub router in the house, but, >> >> I'm not going to be pushing massive throughput, and I think it'll be >> >> minor. >> >> >> >> Adam: Which kind of Cantenna dis you build? I guess it was successful, >> >> what kind of range are you getting? >> >> _______________________________________________ >> >> SkullSpace Discuss Mailing List >> >> Help: http://www.skullspace.ca/wiki/index.php/Mailing_List#Discuss >> >> Archive: https://groups.google.com/group/skullspace-discuss-archive/ >> > >> > >> > >> > _______________________________________________ >> > SkullSpace Discuss Mailing List >> > Help: http://www.skullspace.ca/wiki/index.php/Mailing_List#Discuss >> > Archive: https://groups.google.com/group/skullspace-discuss-archive/ >> _______________________________________________ >> SkullSpace Discuss Mailing List >> Help: http://www.skullspace.ca/wiki/index.php/Mailing_List#Discuss >> Archive: https://groups.google.com/group/skullspace-discuss-archive/ >> > >
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