Which antenna?

Hi

I have attached a picture (from Google Earth) which shows the layout, topography and terrain of the area in which I wish to setup a wireless network by connecting to a transmitter that is already mounted on a building. I would like to connect to the wifi transmitter for both myself and our neighbour by putting an antenna up on the hill and plan to power it with a battery and solar panel.

The person who owns the transmitter is way too busy to setup this connection for us so I thought I would have a go myself. The neighbour and myself will be paying the owner of the transmitter a monthly fee for the connection.

I have no experience with RF, antennas, etc, so I'm hoping someone can help me out with the equipment required to setup this network (not necessarily for the solar power side of things, kind of unrelated). I have browsed through the products listed at Go Wireless NZ Shop Selling 802.11 Wifi Cables, Connectors and Antennas but can't decide which type of antenna or which wireless radio I need.

Listed below is basic information for the setup:

-- The antenna (B) will be in line of sight of the transmitter (A), our house (C) and the neighbour's house (D).
-- The antenna (B) will be on top of the hill ABOVE both our house (C) and the neighbour's house (D) and will be mounted up in a tree (for LOS).
-- Distance from transmitter (A) to antenna (B) = 1.5 km
-- Distance from antenna (B) to our house (C) = 0.16 km
-- Distance from antenna (B) to neighbour's house (D) = 0.33 km

Do I need to contact the owner of the transmitter to ask for the transmitter specs before the necessary equipment can be determined?

Any advice would be VERY much appreciated.

Attached Images

 

First, I am assuming that the transmitter you described transmits on the 802.11g standard. That is essential for using low-cost routers. You will need high-gain signal antennae's on ( B ), with a signal repeater/booster access point there also. The idea is to set up ( B ) as an access point to get the weak signal, boost it & re-distribute it. Routers at the other homes would do well with high-gain ears as well. The stated spec. for signal range on a standard signal is 300 yards, but as you mentioned terrain and other factors affect the signal as well. The straight-shot signal from (A) to ( B ) may work. Adding highest-gain rabbit ears available may make it all work. It's the distances involved that are working against you most.

That sort of distance is easy. The main problem I can see is that both antennas on the 1.5km link are likely to be similar heights and shooting over water. I would find out the height of both antennas above sea level so you can determine if the fresnel will hit the water. Reflections of the water can cause big problems.

Have a look at http://www.eol.co.nz/products_wireless_hw.php their 'jet fighters' are great!
POE and the panel and radio are all in one unit. Makes mounting and config really easy.
But do watch out for the fresnel zone over water!

If I was doing this I would consider having target antennas on the repeater which point towards each of the houses. The spread between the two houses is to much for a single antenna I think.

The 1.5 km link is easy. For lowest cost grab a Linksys WRT54GL router and put openWRT on it. These are great as they take 12 volts at 1 amp. I have had a solar setup powering one of these with a car battery which gives a couple of days storage. You are going to need a big panel to provide enough juice and maybe want to also consider if you can use a small windmill to give a more reliable power supply.

This antenna should keep you going through good and bad weather.
WISP Router, 2.4ghz 24dbi Die Cast Antenna N-female, Client Antennas

Then I would consider buying two more WRT45GLs & antennas - one for each house to repeat the signal to the houses. These would be mounted with the antenna which receives the 1.5km link.

Antenna choice will depend on the terrain. At these distances a decent antenna should reach your linksys boxes inside the house. If this doesn't work you will need to put receivers on the roof of the houses.

Some people are going to say extra antenna and routers to repeat the signal on the hill is overkill but I think you are going to need them to be sure that you get a reliable signal.

Total cost should be around $800 for five routers and antennas excluding the windmill for the hill. This is a lot so you need to think if cable is an option.