Look in the ARRL (Amateur Radio Relay League) Antenna Book for a vertical phased array. Also look a Doppler direction finding antennas. That should get you started with a vertical solution. You should be able to electrically sweep it by changing the phasing electrically. If you really want to pull a rabbit out of the hat do electrically with a horizontally polarized antenna. You pick up about 5 dbi going from vertical to horizontal due to ground loss. Gordon Gordon Couger gcouger@rfdata.net 624 Cheyenne Stillwater, OK 74075 405 624-2855 GMT -6:00 -----Original Message----- From: Dennis Plunkett To: PICLIST@MITVMA.MIT.EDU Date: Monday, May 18, 1998 11:25 PM Subject: Re: PIC "Smart antenna"? >RE Smart Ant > >I have done one of these. The RSSI signal is generally good enough, you will >require some smart logic to "Hunt" for the signal. Check to ensure that the >RSSI has enough range and doesn't flatten out to much at the lower signal >levels. Converting this into an 8 bit value will be more than enough. > >Now for the TIPs on controlling the ant, use a stepper drive, as vibration >and wind and that sort of thing will cause the ant to move. Note that it is >difficult to track a fast moving target! >Fade margins will cause trouble ,be ready for these as levels of 100dB per >second can be found. >Ensure that you don't attempt to track to a low level RSSI signal ie. Chose >the lowest level carefully. >Ensure that the RSSI is after all the IF stages, as adjacent channels may >cause you to lock onto a non existent signal > >That's about it, you will find out other smaller (Trivial) problems as you >continue. > > >Dennis > > >-=====================================================================- > >Dennis Plunkett: Embedded Hardware, Software design >NEC Australia DRMASS >Line Interface cards >TRX software >ISDN interface card >ph 03 9264-3867 > >-=====================================================================-