WLAN DXing

with the help of

Radio Mobile prediction software

 

This page explains an experiment to find how far I could get two 2.4GHz, 802.11b wireless bridges to connect to each other.  To do this I stumbled across some free software by VE2DBE called Radio Mobile.  This software is a tool used to predict the performance of a radio system. 

Hardware used:

2 off Cisco BR350 Bridge.     

I was given a couple of old Cisco BR350 Wireless Bridges. These basically look like an access point and allow you to bridge two networks over a 2.4GHz radio path.  In the UK the Bridges have an RF output of just 35mw.

2 off Cisco Yagi (13.5db)

To complement the Cisco bridges, I used a 13.5db gain Yagi on each bridge.  This improved the range dramatically due to the high gain of the yagis.  Below you can see one of the yagi's installed at about 10m above the ground at my QTH.  Just below the yagi and tucked away to the right of the aerial mast is a black ABS box that stores one of the wireless bridges.  At 2.4GHz there is high loss in the coaxial feeder, so I decided to keep the feeder length to a minimum and mount the bridge as close to the yagi as possible.  The ABS box has holes drilled in the bottom to let any water or condensation escape.

 

Radio Mobile software used to predict the performance of the radio system. 

In the screen grab below, on the left is the mobile station called "LUB to FAR".  This is a location on a small road between Lubenham and East Farndon where I could park my car and experiment with the aerials.  On the right of the image below is my home QTH and is called G1IVG.

You will see the angle that the mobile aerial has to point in from LUB to FAR is 71.6 and the overall distance is 3.49km.  To get the signal strength prediction to be correct, you have to tell the software your operating frequency, power output and antenna type and gain etc.

The picture below is also from Radio Mobile which has options to plot the radio path on a Google Map, Yahoo Map plus others. 

To the west of the LUB to FAR location was another spot in the same beam heading as my QTH and about another 2.4km away, however the path was obstructed by some high ground and no connection was found.  In the summer I plan to move my yagi on the mast and point it in another direction, possibly to the north to see if I can improve on the 3.49km.......Watch this space for the G1IVG to Cranoe 7.71km experiment.