WiFi direction finding.

[Ted Ozolins]

Net Llama! wrote:

>On Fri, 26 Dec 2003, Ted Ozolins wrote:
>  
>
>>Jeeves Moseley wrote:
>>
>>    
>>
>>>I've got a idea.  I've got the hardware stuff down to a fine art, but
>>>I have no idea on how to do the software.  if you use 3 cell phone
>>>antennas formed in a triangle and took the signal strength from all 3,
>>>you'd be able to use that information to effectively find the incoming
>>>direction of the WiFi signal.  if you wanted to take it a step
>>>further, then you could make the transitions transmit in phase and
>>>extend the distance of the system with out boosting the power.
>>>Adversely you could also use the third antenna to create a virtual
>>>ground plane behind the two receiving antennas to boost their
>>>receiving power.  If you know of any talented Windows programmers who
>>>are interested in trying this, please let me know.  I'm willing to do
>>>the hardware mods, etc, but as I said, I have no idea on the
>>>software.  Thanks again.
>>>
>>>Scott
>>>
>>>
>>>------------------------------------------------------------------------
>>>
>>>      
>>>
>>Why would you need software? Sampling the signals obtained by switching
>>the antennae one at a time at a speed of about 1-10kHz, you could
>>process and measure the dif using an analog meter. To give you relative
>>direction use two antennae and by using three would give you relative
>>field_strength and direction. Ham operators have been using this method
>>for years.
>>    
>>
>
>Also, why do you need a windows programmer?
>
>  
>
One more why. Why would you want to waste the resources of a full blown 
desktop to do the job of a pic?  These little besaties can compare the 
levels and display them on a series of LEDs .  With some extra work you 
could make up a matrix of LEDs' so that you would get a line of lit LEDs 
pointing to the source of the signal.

-- 
Ted Ozolins(VE7TVO)
Westbank, B. C