Deven07
@charter.com
| 2.4gHz WLAN Segment through a bit of foliage?
Hi, I'm looking to install a WLAN segment about 3/4 mile across a lake, with a very small strip of foliage at each side posing some interferance concerns. This connection would be installed in hopes of creating a very small home brew WISP on the side of the lake with no connectivity.
On each side of the 3/4 mile middle, there is some treeline probably 10 yards wide, through the tops of some sparsly foliated poplars on one side, maples on the other, again probably 10 to 20 yards wide. I can see through the tree(s) pretty well to the other side, but there definately is no clear window without any foliage present. Inside these short treelines is obviously no obstruction whatsoever, being over the lake. Each antenna would probably be 20 - 40 feet high. Do you think this small amount of tree interference is going to make this connection tough to establish? I've seen some 2.4gHz applications blow through some trees before, but never have had hands on on a project that tried it. I was thinking of using 14db panel antennas with linksys WAP54G's. Any help you can give would be much appreciated! |
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slipstream1
Premium
join:2005-11-15
Jacksonville, TX
| Your problem would be attenuation instead of interference. As for the main question, 2.4 Ghz might be able to do this on this short scale, but there is only one way to know for sure, buy some inexpensive 2.4 Ghz gear and try it.
I would not fool with the Linksys stuff. Go buy 2 of the $96.00 High Gain Antennas sub $100 CPE's and use that stuff. You may even try one of his units with a integrated panel antenna. |
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superdog
I Need A Drink
Premium,MVM
join:2001-07-13
Lebanon, PA
| said by slipstream1  :I would not fool with the Linksys stuff. Go buy 2 of the $96.00 High Gain Antennas sub $100 CPE's and use that stuff. You may even try one of his units with a integrated panel antenna. I would also try and use 45 degree polarity instead of vertical or horizontal, as some say it seems to work a little better thru trees?. I think I would be more worried about issues from the lake then the trees?, as water can create some pretty crazy multipathing issues, especially when the lake is choppy, as each one of those little waves creates a surface to reflect RF, causing not only Your intended signal, but a bunch of reflected ones also. To give You a simple example of this, have You ever noticed when driving in Your car and You stop at the red light, Your FM radio starts acting up?, and then after You move forward a foot or two, it starts to come in clear again> This happens because the intended signal and a reflected one hit the antenna or radio at the same time, causing them to cancel each other out, and when You move forward, You move out of the reflected signal, and the radio starts to come in clear again.
Newer radios use this chaos to their advantage(OFDM), but OFDM is only available in 802.11G and 802.11A radios, and 802.11b radios just puke and die because their receivers can not handle the mess. 
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lutful
Premium
join:2005-06-16
Ottawa, ON
| reply to Deven07
said by Deven07 :
I can see through the tree(s) pretty well to the other side, but there definately is no clear window without any foliage present. You will be fine with 250mW TX power with 14dBi antenna, or 100mW TX power with 19dBi antenna.
I say this because I have longer links where I can barely see a light on the other side at night after all the leaves fall from the trees. |
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deven07
@charter.com
|  Hey thanks for the great info that was just what I was looking for...some reassurance that it is within the realm of possibilities! You all are very helpful, thanks again! So I think Ill go ahead and roll the dice and buy the equipment to get this link going. Any suggestions as to any economical brands/models of bridge/antenna that you would reccomend? |
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lutful
Premium
join:2005-06-16
Ottawa, ON | Deliberant makes a model with exactly 250mW TX/ 14dBi spec and you can turn down the power to 100mW in their
19dBi model.
You could use one of each model for this link - put the 19dBi at the end with more clearence. |
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deven07
@charter.com
| Nice! Thanks lutful, the DLB2300 looks just right, especially with the built in POE. This solution will actually save me money and it looks like I'm getting way better equipment. The only question I have is the ground...have you used this or similar boxes and can tell me if there is a ground post built into the box that I can run ground wire from, or do I need a inline ethernet ground? Lightning is definately an issue in my neck of the woods! |
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lutful
Premium
join:2005-06-16
Ottawa, ON
| Citel or Hyperlink or Teletronics CAT5 lightning protectors will add extra protection to Ethernet port on the DLB2300.
You could bond the PCB metal shield to the protector's ground lug with a heavy gauge wire and then ground the whole system, but there are many different ways.
BTW, very few radios integrate RJ45 lighting/surge protection directly on the PCB like the new DLB2700 PCB. So even if the radio PCB is grounded to metal enclosure, the CAT5 PoE and data signals are not fully protected. |
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bito
Premium
join:2001-10-08
Atlanta, GA
| Just as a quick clarification, the DLB2700 PCB does not have the surge suppressor built into it. The ethernet surge suppressor is a standalone unit inside the enclosure that grounds to the rest of the internal chasis and then to the external ground screw. You can see the pics on the FCC site for FCC ID RIW-ZW-2000 from Zinwell.
Caleb |
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