johnson 2 Posted December 12, 2005 Report Share Posted December 12, 2005 how do you build a antenna for one cause i need to know how? Quote Link to comment Share on other sites More sharing options...
Guest Decade Posted December 12, 2005 Report Share Posted December 12, 2005 Hi johnson 2!Are these two way radios handheld or base units?What kind of connectors for external antenna do they have and what is the output power from them? Quote Link to comment Share on other sites More sharing options...
johnson 2 Posted December 17, 2005 Author Report Share Posted December 17, 2005 the units are hand held and there is no antenna output conector i open them Quote Link to comment Share on other sites More sharing options...
Guest Decade Posted December 17, 2005 Report Share Posted December 17, 2005 Hi johnson 2!It might be possible to solder a coax cable to the PCB were the antenna is connected but it is not that easy, you got to find where the ground is on the PCB and hopefully the impedance is 50ohms.A dipole is 1/2 wavelength, formula: antenna length in meters=150/(frequency in Mhz that the antenna is intended for) if you wish a 1/4 wave antenna simply divide the result with 2.Impedance of a 1/2 wave dipole is about 75 ohms and a 1/4 antenna with groundplanes can be tuned to 50 ohms by adjusting the angle of the groundplane.Just a warning.. by doing these changes you can kill the power amplifier in you hand held transceiver. Quote Link to comment Share on other sites More sharing options...
Guest Decade Posted December 17, 2005 Report Share Posted December 17, 2005 Here's a link to a 1/4 wave antenna in Swedish though ;Dhttp://www1.shellkonto.se/icom2002/pmr/2/index.htmLengths L1-L5 160mm but usually ground planes (the 4 down going wires) are made 5% longer than the vertical pin. If you are familiar to the chassie connector SO234 you know that there is 4 holes for mounting, these holes are used for the ground planes, you simply solder 1,5mm brass or copper wire into the holes.Good luck! Quote Link to comment Share on other sites More sharing options...
johnson 2 Posted January 12, 2006 Author Report Share Posted January 12, 2006 >:( Quote Link to comment Share on other sites More sharing options...
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