300m wireless connection no go

Heres the situation, we are hooking two flats up together. Distance of about 300m

The hardware at flat 1 is this
Netgear wg311
http://prism54.org/ for prism gt

connected to this aerial that we built for both ends.
http://www.wireless.org.au/~jhecker/helix/

at flat 2 is a Linksys WRT54G Access Point.
http://www.isel.ipl.pt/~pribeiro/LinksysWRT54G.html

Using LMR 195 cable, at our end we have about 3 meters of cable, on their end they have about 6.

We have line of sight. But our signal strength is crap as. we're lucky to get 15% and even then its not strong enough to connect to. Using network stumbler we're lucky if we get -80dB.

We've boosted strength to Max, removed the covers for the aerials (gave us a couple of percent improvement). No luck.

Any ideas? Might be the aerials.
ill take some pics of the line of sight, just in case people reckon that a bird in the far distance crapping is interfering with the signal. Cos then at least ill have a better idea, and ill be able to kill the damn bird :twisted: .

Ta

I think you will find the Helix antennas are not working correctly. I built the same ones and mine did nothing, ZERO.

Then after browsing the web, I came across a site (I think in Germany) where a guy spent some time and recalculated the diamensions. The design is meant to be smaller in diameter and shorter.

Mine now sit in the garage collecting dust, which is a pain, but I failed to recheck Mr Hecker's formula as I thought it would be OK.

If a helix is built correctly you can get some great range out of them but you need them both to be matched, If you have wired them left hand they both have to be that way otherwise you will get naff all signal. Also the feeder and wire has to be prety close to perfectly spaced otherwise this will degrade your signal.

For this link I think you would be better off with another type of antenna. Not trying to pimp our products but http://shop.borg.co.nz have a reasonably inexpensive 14dbi pannel antenna that would work well for your installation.

Als it would be a good idea to check your cables, make sure they have been correctly made as if a pin is out of place or there is a short you would get the same thing.

Regards
Andrew Hooper

6 metres of lmr 195 wont be helping! that stuff is very lossy!

im now in palmy, ohakea actually but keen to get a PN network established. You guys keen? have you added yourself to nodedb.com?

wookie

Problem solved.

Okay for everyone out there, something that might be useful.

The helical antennas are fine (sort of)

We had an Alstrom person double check the aerials. Since they are home made when using a specan, we found that the aerials we not exactly the same (no surprise there). Due to this one aerial was great on one channel and the other was good for another channel. So first of all that didnt help.

So we used one Yagi aerial from the other flat. That fixed the channel problem.

Next one. The Linksys WRT54G AP seems to be incompatible with the Netgear wg311, put the AP and the netgear card next to each other and they refused to connect. Luckily we had another card that we are using, but it is only 11Mbit. The connection is good enough now that we have cut down the power output on the AP to 15dB, instead of the max 20dB we were using before with no luck.

So its going now. The [MAD] flat and the remenants of the Collective are one... excellent.

Hmm, dont see why not.

Adding to nodedb... dont know, dont want to really be advertising our position too much.

DAMN! youre not kidding, over the total 6 metres and 4 of cable used this is what is being lost.
over the 6 metres - 3.7db. and an efficiency of 43%
over the 4 metres - 1.2db and an efficiency of 76%

http://www.timesmicrowave.com/cgi-bin/calculate.pl

Also i cant seem to get the damn map location working for palmerston north. it shows the entire west coast of N.Z pretty much. So i cant add myself to nodedb.com

might look into getting better cable

what about doing POE

I have got a spear Antenna and AP here that were can use
But will have to fined a good location
ohakea to palmerston is like 15-20km

a couple of old sky dishes with biquads will make that sort of distance.. assuming LOS etc..

and a dam hall in the way i think :cry:

If you are keen to try and link some more people up over PN then drop me a an email to wookie@nzwireless.org with your contact details. I have all the gear i need here, infact i am making a small network here at the moment. Hoping to get a building in Bulls to rebro to PN.


Cheers,


Scott

Sure im keen...

Isnt POE used for powering devices? Power Over Ethernet? Dont think it can be used for the cabling for the aerial. I could be wrong though. Then the next question is would it be good at 2.4GHz?

Yes it is Power Over Ethernet
What you can do is have a short cable from the AP to the aerial
Them you can put your ap in the roof or in a Weatherproof Enclosure on the pole

Sorry, you're right. Just that I havent had much sleep in a while. Went to be at 2 on Wednesday, woke up at 8, then went to bed at 5 Thursday morning. So So wasted. I couldnt find my way out of a paper bag right about now.

Joys of 4th year Engineering degrees...
8O