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EH Antennas for Hams. September 2004 by Ted Hart W5QJR. Courtesy of EH Antenna Systems. What Is An EH Antenna?. It is a revolutionary concept that allows small antennas to outperform large antennas. EH Antenna – An Example Located at Eatonton, Georgia.
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EH Antennasfor Hams September 2004by Ted Hart W5QJR Courtesy of EH Antenna Systems
What Is An EH Antenna? It is a revolutionary concept that allows small antennas to outperform large antennas.
What Are The Defining ParametersOf An EH Antenna?___________________________________________________________________________________________________ • Small Size
What Are The Defining ParametersOf An EH Antenna?___________________________________________________________________________________________________ • Small Size • + Low Height
What Are The Defining ParametersOf An EH Antenna?___________________________________________________________________________________________________ • Small Size • + Low Height • + No Radials Required
What Are The Defining ParametersOf An EH Antenna?___________________________________________________________________________________________________ • Small Size • + Low Height • + No Radials Required • + Broad Bandwidth
What Are The Defining ParametersOf An EH Antenna?___________________________________________________________________________________________________ • Small Size • + Low Height • + No Radials Required • + Broad Bandwidth • + High Efficiency
What Are The Defining ParametersOf An EH Antenna?___________________________________________________________________________________________________ • Small Size • + Low Height • + No Radials Required • + Broad Bandwidth • + High Efficiency • + Low EMI
What Are The Defining ParametersOf An EH Antenna?___________________________________________________________________________________________________ • Small Size • + Low Height • + No Radials Required • + Broad Bandwidth • + High Efficiency • + Low EMI __________________________________________________________________________________________________________ • = A Great Antenna for Hams
The Number 1 Question,does It Work? * FCC Type tests prove it is a very good AM Broadcast Antenna * Many Hams use home made EH Antennas *Companies in Italy and Japan manufacture EH Antennas for Hams *EH Antennas are in commercial use * EH Antennas will be the preferred choice in the future for most communications applications
QUESTION #2 – HOW DOES IT WORK? HIGH CURRENT H FIELD E FIELD
L1 C1 Coax Phasing Coil L2 C2 The Evolution Of The EH AntennaL+L NETWORK
L2 L1 Coax Phasing Coil C2 C1 The Evolution Of The EH AntennaL+T NETWORK
The Evolution Of The EH Antenna *STAR* EH ANTENNA CYLINDER PHASING COIL CYLINDER TUNING COIL COAX REACTANCE COIL
EH Antenna Analysis Program Measuring 3 dB Resistance Definition - - - Q=XL/R=F0/BW Therefore: R = BW*XL/ F0 Radiation Resistance = 3 dB Resistance – Loss Resistance
EH Antenna Analysis Program C = 0.55*L/D*D + 2.06*D
EH *STAR* ANTENNA CYLINDER PHASING COIL CYLINDER TUNING COIL COAX REACTANCE COIL
ROLL YOUR OWN EH ANTENNA • STEP 1- OBTAIN TEST EQUIPMENT • SIGNAL GENERATOR • FIELD STRENGTH METER • VSWR BRIDGE • IMPEDANCE BRIDGE (NICE)
ROLL YOUR OWN EH ANTENNA • STEP 2 – BUILD COAX CHOKE ABOUT 1/8 WAVELENGTH OF COAX WOUND IN A COIL LOCATE ABOUT 3 FEET BELOW THE ANTENNA
ROLL YOUR OWN EH ANTENNA STEP 3 - ASSEMBLE THE ANTENNA DO NOT TRY TO MAKE THE FIRST ONE PRETTY –USE ALUMINUM FOIL OVER PLASTIC PIPE USE 2 TURN FEED TAP – NO SOURCE COIL YET
ROLL YOUR OWN EH ANTENNA STEP 4 A - TUNE THE ANTENNA MEASURE OPERATING FREQUENCY WITH FIELD STRENGTH METER – TAP TOP OF TUNING COIL TO CHANGE FREQUENCY
ROLL YOUR OWN EH ANTENNA STEP 4 B - TUNE THE ANTENNA PLOT IMPEDANCE or COMPARE MAX RADIATION AND MINIMUM VSWR FREQUENCIES
ROLL YOUR OWN EH ANTENNA STEP 4 - TUNE THE ANTENNA C – INSTALL SOURCE COIL D – ADJUST FEED FOR 50 OHMS E – RECORD IMPEDANCE PLOT
IMPEDANCE WITH REACTANCE COIL 3 dB Bandwidth = 269 KHz
WEB SITE • www/eh-antenna.com