[MLB-WIRELESS] Directionality...

Tony Langdon, VK3JED vk3jed at optushome.com.au
Mon Aug 7 12:17:13 EST 2006

At 12:00 PM 8/7/2006, Gustaf Bjorksten wrote:

>Antenna-based DF Ideas:
>* Omni-antenna dopplar array

Doppler systems perform poorly in reflective environments (urban 
clutter being an example), they also lack sensitivity.

>* Loop antenna (i suspect this won't work effectively as a DF 
>antenna at such high frequencies, but i need to explore this further ;)

A gridpack dish, Yagi or other high gain directional antenna will do 
better.  Most foxhunters use Yagis down to 144 MHz.

>* Directional antenna w/ search-pattern software controlled stepper 
>motors (all directions) rotating head and signal meter or spectrum analyzer

Can be made to work. :)

>Secondary, bolt-to-directional-antenna DF Ideas:
>* GPS and AHRS (or if not an AHRS then digital compass and digital 
>bi-directional inclinometer)
>* Powerful laser technology?
>Or some combination from all the above.
>BTW, I have or am building equipment to try all the above with the 
>exception of the laser stuff. My research is for a different 
>application than is the situation proposed here, but there are many 
>similarities in the problem space.

For a bunch of hobbyists, the easiest methods (non LOS) are the 
GPS/map/compass and UHF CB directional antenna measurements.  These 
are cheap, provided a small percentage of us have the necessary gear 
(GPS and UHF CB).  I'm happy to help out when I can. :)

My experience is that simple, but effective methods are the ones that 
will be utilised the most. :)

73 de VK3JED

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