DG834G + 14dbi External directional antenna

[mbeylis]

Good Day. I am trying to set up a wireless network with my neighbour and myself, we are at most 50m apart. My setup is as follows. My Netgear Dg834G router sits in my lounge, roughly half way between my neighbours PC room and my PC room. I have 2 ethernet cables running through my roof to my pC room from the router. I have attached a 14dbi external diretional antenna on my roof which points at my neighbours house. The length of the cable from the router to antenna is 10m. Despite this configuration my neighbour still only gets a very poor wireless signal which comes and goes. Please help, what am I missing.I know for a fact that the 14dbi antenna I have used to connect to machine previoulsy which were 2km away. There are some trees and plants, and obviously walls between my neighbour and myself but I have place the external attenna higher than these pointing down. My neighbour has a mecer wireless network card in her PC to which I have added a 7dbi D-link antenna. Please can someone give me some assistance here as I am now frustrated and out of ideas as well as baffled. Thanks Mark

[deddard]

Hi - Welcome aboard!

Can you give us the details of the antennae used? (make/model) so we can check them out.
Setting up antennae can be awkward - grounding etc, together with cable length can cause problems.
I checked out the buffalo site for their directional antenna, and the cable length seems ok, but you will always get some sort of losses.
post back with the specs and we'll see what we can do (there could be someone here who does this stuff all the time, and the extra info will prove useful)

Also bear in mind that manufacturers specs should be taken with a pinch of salt - the buffalo unit I checked out said 60 metres was ok, but any electromagnetic signals are going to affect this.
Mobile phones etc can interfere (even on directional antennae) as can just about anything else on 2.4Ghz.

[mjc]

What type of construction is her house?

Some things to think about...aluminum siding, foil backed/faced insulation, concrete block, brick, other metal or stone.

[mbeylis]

Hi, will try and find out the make and model of the external antenna, because I didnt get it new, outta the box per say I didnt really take note of the make. As for the neighbours house we live in a townhouse complex so her house is the same as mine which is jsut your ordinary brick and plaster as far as I can tell. I am thinking that I will have to get my neighbour an externall antenna too on her roof and point it at my external antenna. Thing is I am trying to save money. To get her another cable with connectors is gonna cost me another R150 (about $25) if I modify her D-link desktop antenna whose original cable is only 300mm long. Another antenna like mine will cost about R800 (about $135). I was wondering if there wasnt a setting on the netgear DG834G router to boost the transmitting power but cant seem to find anything. I was even thinking of going as far as to get her a Wireless Acess Point and put it in client mode in place of her mecer wireless card. Also thinking of borrowing my friends wirless laptop and using netstumbler to test the surroundings. Is there any easy way of seeing if maybe there is something in nearby vicinity which is interfering with the signal. I have played around with the 13 different channels that I can use and 6 seems to be the best

[mbeylis]

Another thought is that the 10m cable that I use to connect the router to the external antenna was made by my friend and myself. we used RJ59 cable which we bought from an electrical store. Not sure if its the right stuff?

[mbeylis]

Is there not a (hidden) setting or something in the netgear DG834G router to boost the strength of the antenna signal especially considering that I have now added an external antenna?

[deddard]

Haven't found the direct info yet, but your suspicions about the cable may be on the right line.
THe only info I could find regarding impedance is that RJ59 is 75ohms, and there are a few problems reported by people. These mainly involve the unsuitability of this cable for digital signals.

I originally thought the correct cable would be 100ohms, but after searching around, it is more likely that you need a 50ohm cable as in this pdf document from buffalo (specs for their antennae)
http://www.buffalotech.com/downloads/Antenna%20Manual.pdf

a search on google comes up with http://www.alloy.com.au/products/WL_ANT_OPS.htm

your signal would drop considerably with a 75ohm cable. there is a lot of energy being wasted within the cable, rather than being correctly transferred to the antenna.
It's been a while since I did any electronics theory, so I can't tell you the mismatch in decibels, but I'm sure someone here could do it :D