Re: Signs of foliage causing dropouts of signal? in Wireless Service Providers http://www.dslreports.com/forum/r20434888 en Fri, 09 Jan 2009 01:04:30 EDT Fri, 09 Jan 2009 01:04:30 EDT Re: Signs of foliage causing dropouts of signal? http://www.dslreports.com/forum/remark,20484705 vincentfox : Get to tree-trimming, or apply some defoliant.

I had a quarter-mile link through foliage and it would work decently enough until summer came along and it rained for more than 10 minutes. Wet leaves are a signal-sponge. Consider also that signal is not like a laser beam. Anything any in the Fresnel zone path will be an obstacle to radio signal, which could be a tree some feet off to the side.]]> http://www.dslreports.com/forum/remark,20484705 Wed, 14 May 2008 23:21:51 EDT Re: Signs of foliage causing dropouts of signal? http://www.dslreports.com/forum/remark,20440358 EMC_guy : Another important factor for NLOS is the radio's "delay spread" specification. Higher number makes it more immune to multi-path effects.

said by stargazer :

What type of units have the ultra-fast AGC?
Most WiFi chipset companies (Atheros, Broadcom, Ralink, Realtek, Marvell) integrate transceiver with a basic AGC circuit. I am ordering them by my own perception of design quality - there is no way to improve their behaviour by WISP vendor. However they could use custom PCB design with with higher quality external transceiver and AGC and LNA. This will increase system cost.]]> http://www.dslreports.com/forum/remark,20440358 Tue, 06 May 2008 14:36:30 EDT Re: Signs of foliage causing dropouts of signal? http://www.dslreports.com/forum/remark,20438012 cmaenginsb : Shooting through or around any obstruction involves multi-path propagation. This is the reflection of signals by various objects in it's path such that the radio can possibly "see" more than one signal. It is possible that the multi-path that is giving you -72 goes away for a few signals to the point the radio loses connection.]]> http://www.dslreports.com/forum/remark,20438012 Tue, 06 May 2008 01:29:04 EDT Re: Signs of foliage causing dropouts of signal? http://www.dslreports.com/forum/remark,20437970 anon : When I see these fluctuations it is not rainy or windy. it is doing this on sunny calm days. I had some issues when there was no foliage but did not obtain the pinging software until after I had some foliage so I do not know if the foliage is a factor or not.

What type of units have the ultra-fast AGC?

I have been looking at the LigoWave 900 mhz units for $214 and those support WDS. Has anybody had any luck with the WDS on the LigoWave units (particularly the 900 mhz units)? If I could use WDS with these then I could have the cost almost the same having one of these units in place instead of two like I have now for my hops although I would not have a 2.4 ghz AP.]]> http://www.dslreports.com/forum/remark,20437970 Tue, 06 May 2008 01:15:35 EDT Re: Signs of foliage causing dropouts of signal? http://www.dslreports.com/forum/remark,20437444 lutful :
said by stargazer :

I was getting upper -60's before the foliage and now get around -72 so I did not lose much signal due to the foliage.
I posted a real-time graph long ago that shows upto 40dB rapid RSSI fluctuations on a windy and rainy day in mid-summer. So reliable foliage NLOS links need a receiver with ultra-fast AGC (automatic gain control) circuit.]]> http://www.dslreports.com/forum/remark,20437444 Mon, 05 May 2008 22:58:28 EDT Re: Signs of foliage causing dropouts of signal? http://www.dslreports.com/forum/remark,20435811 89555781 : If you trying to shoot through trees with 2.4GHz, your results will vary despite what brand of CPE you use. The leaves can be dry and still one minute and moving the next. They may be dewy early in the morning or wet after a rain shower. 2.4GHz is a clear line of sight frequency. Trees, walls, hills etc. will all affect this.

Your best bet is get above the trees.]]> http://www.dslreports.com/forum/remark,20435811 Mon, 05 May 2008 17:34:16 EDT Re: Signs of foliage causing dropouts of signal? http://www.dslreports.com/forum/remark,20434888 anon : I am using a pair of new High Gain radios with a built in 15 db antenna. There are trees and foliage in the way. The cards run at 26 dbm and I think the cutoff on the signal is around -88. I was getting upper -60's before the foliage and now get around -72 so I did not lose much signal due to the foliage. I didn't think that there would be inconsistency with the signal with trees in the way. Sometimes it will have a solid signal for a little while after a reboot then it will start losing packets or it will act like it lost the signal altogether then the signal will come back solid again. Shouldn't there be more consistency with the signal than that even through trees? I don't understand how a signal can go from -72 to nothing for a while then all of a sudden come back unless there is a problem with the radio. I have swapped out the client radio with the same results. Perhaps I will need to swap out the AP to see if that resolves the problem.

I figure 900 mhz would have no problem shooting through the trees but it is more expensive. My house is on the other side of this link and I do not see serving very many clients (maybe just a handful) but since I live in this area and want to monitor the rest of the network then I would like to have the link established without spending a lot of money especially since it is not a long link.

When I stated that there was no foliage, that was a typo, I meant to say that there is foliage. I have done shots through foliage before that were close in so it surprised me that this shot through the trees did not work as close as it is. I was having issues before the leaves came on as it was line of site before I had foliage.]]> http://www.dslreports.com/forum/remark,20434888 Mon, 05 May 2008 15:43:48 EDT Re: Signs of foliage causing dropouts of signal? http://www.dslreports.com/forum/remark,20434559 EMC_guy : Of course foliage will affect Ghz frequency RF signals! But many WISPs are doing short range 2.4Ghz links through foliage. See this recent thread I started (
»WISP and foliage ) and search for many old threads in this forum.

Based on many differing opinions, you could be more successful using good quality CPE with a medium gain (14-17dBi) panel antenna. That is what I am doing at this moment with a 500 meter test link - I started with -65dBm signal in early April which has fallen to -72dBm now. I expect it to go down to -78dBm by mid-May but my radio has -86dBm sensitivity at 11Mbps.]]> http://www.dslreports.com/forum/remark,20434559 Mon, 05 May 2008 13:31:52 EDT Re: Signs of foliage causing dropouts of signal? http://www.dslreports.com/forum/remark,20429712 LLigetfa :
said by stargazer :

...Will foliage in the link cause this?
...
The distance apart is around 1500 to 2500 feet line of site without folliage.
Your post is a contradiction. You ask if foliage could account for the issues but then later go on to say there is no foliage.

There is no mention of what radios are used, what power levels, what antennas, what EIRP. A less than half mile shot should be able to yeild better than -70 and I suspect (given that scant bit of info) that you are picking up interference. It could also be junk radios.
--
Strange as it seems, no amount of learning can cure stupidity, and formal education positively fortifies it. -- Stephen Vizinczey]]> http://www.dslreports.com/forum/remark,20429712 Sun, 04 May 2008 11:27:00 EDT Re: Signs of foliage causing dropouts of signal? http://www.dslreports.com/forum/remark,20429680 viperm : More details... I.E what type of gear are you using, what type of receive sensitivity does the CPE and AP have.

Is there trees or foliage in the way or not?

Try moving the CPE to another location. Its possible your getting some kind of reflection form where it is now. IT could be foliage but with out more info its hard to tell.

Any pics of your install?
--
ComTrain Certified Tower Climber. American Tower Certified approved contractor. Wireless consultants.]]> http://www.dslreports.com/forum/remark,20429680 Sun, 04 May 2008 11:19:49 EDT Signs of foliage causing dropouts of signal? http://www.dslreports.com/forum/remark,20419344 anon : I am running software that allows constant pings to different ip addresses. I have been having issues keeping connections on a few of my links and am trying to nail down the problem. It seems like a reboot fixes the issue for a little while then it startd dropping packets again. I tried a few different client radios but a different client radio did not help.

Sometimes the packets would be solid while other times it will be choppy and at times it will go from solid packets to a sudden dropoff while other times it will be choppy then drop off all of a sudden. Will foliage in the link cause this?

I get a signal of -70 to -72 (the AP sees the client this strong as well). It will be that strong without a fluctuation of anymore than 1 or 2 db before it drops out completely. I would think that the signal would get weaker instead of getting choppy or dropping out from time to time if there was an issue with folliage. There are no hills in between the link. The distance apart is around 1500 to 2500 feet line of site without folliage.]]> http://www.dslreports.com/forum/remark,20419344 Fri, 02 May 2008 00:18:34 EDT