Calculating refraction was an attempt to get a rough idea of what angle to deviate from line-of-sight. The 24dBi antennas in use have about a 7 degree beam width (3db down points). If refraction effects at 2.4 GHz suggest a deviation from line-of-sight of, say, 20 degrees, then a second pair of antennas would be useful. If the prediction is beam bending of 5 or 10 degrees, then pointing the primary antenna pair a few degrees off LOS would be fine.
Yesterday, a D-Link Internet camera was mounted behind an optical telescope and pointed along the microwave beam path. I am hoping to correlate some visible phenomena with the RF link problems. I am embarassed to admit that I am still wrestling with Linksys WAP11's. I have decided to upgrade them to Cisco Aironet 350's but have aquired only one of the the required pair. Loren Zemenick -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Behalf Of Sean Lazar Sent: Wednesday, August 27, 2003 12:26 AM To: [EMAIL PROTECTED] Subject: Re: [BAWUG] Microwave propagation speed versus air temperature Hmm, it seems like a temperature inversion would be hard to predict at what height it occurs as it might vary based on air pressure and conditions. Knowing the height seems like it would be important for any calculations. If there is a common pattern then perhaps you can experiment. http://mitglied.lycos.de/radargrundlagen/wellen/ew28-en.html Did you change your radios from linksys wap11? any effect? ----- Original Message ----- From: "Loren Zemenick" <[EMAIL PROTECTED]> To: "Brian Lloyd" <[EMAIL PROTECTED]>; <[EMAIL PROTECTED]> Sent: Tuesday, August 26, 2003 8:59 PM Subject: RE: [BAWUG] Microwave propagation speed versus air temperature > Tropospheric ducting may be an overstatement. I am trying to calculate the > angle of refraction when the beam passes through a temperature inversion. I > have a 5 mile link that has a ridge-top end-point 1200 feet above it other > end-point on the vally floor. If the effect is large enough, I want to set > up a second pair of 24dBi antennas and use antenna diversity. > > -----Original Message----- > From: Brian Lloyd [mailto:[EMAIL PROTECTED] > Sent: Tuesday, August 26, 2003 8:49 PM > To: Loren Zemenick; [EMAIL PROTECTED] > Subject: Re: [BAWUG] Microwave propagation speed versus air temperature > > > Loren Zemenick wrote: > > > Does anyone know how 2.4GHz propagation speed varies as a function of air > > temperature in the 50 to 90 degree F range? > > Trying to work out the formula to predict tropospheric ducting? > > -- > > Brian Lloyd 6501 Red Hook Plaza, Suite 201 > [EMAIL PROTECTED] St. Thomas, VI 00802 > +1.340.998.9447 - voice +1.360.838.9669 - fax > GMT-4 > > -- > general wireless list, a bawug thing <http://www.bawug.org/> > [un]subscribe: http://lists.bawug.org/mailman/listinfo/wireless > -- general wireless list, a bawug thing <http://www.bawug.org/> [un]subscribe: http://lists.bawug.org/mailman/listinfo/wireless -- general wireless list, a bawug thing <http://www.bawug.org/> [un]subscribe: http://lists.bawug.org/mailman/listinfo/wireless
