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ANTENTOP- 01- 2006, # 008

Indoor Helical Antenna



Figure 1 Helical Antenna



Bridge for The 17 meters


Practical Measurement Parameters of the Helical Antenna: I used a home made RF bridge (see Reference 2) for metering of the helical. My Helical has input impedance 35 Ohms at the 20 meters and 46 Ohms at the 17 meters.


Theoretical parameters of the Helical: The theoretical parameters of the helical were simulated with the Helical3 (a special program for helical antennas) designed by R.J. Edwards, G4FGQ. On the basis of these calculation I could assume that the efficiency of my helical is near 15- 12% (in comparison with quarter wave vertical antenna with good grounding). I.e. my helical lose up to 9 decibels or up to 1,5 balls on scale S in comparison with the quarter wave vertical.




1.     Igor Grigorov. Antennas. Practice of Radioamateur. Moscow, RadioSoft


Helical Antenna for 17 meters


2.     Igor Grigorov. Antennas. Tuning and Adjustment. Moscow, RadioSoft, 2002 (In Russian)

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