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EH Antennas for Hams September 2004 by Ted Hart W5QJR Courtesy of EH Antenna Systems.

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Presentation on theme: "EH Antennas for Hams September 2004 by Ted Hart W5QJR Courtesy of EH Antenna Systems."— Presentation transcript:

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2 EH Antennas for Hams September 2004 by Ted Hart W5QJR Courtesy of EH Antenna Systems

3 What Is An EH Antenna? It is a revolutionary concept that allows small antennas to outperform large antennas.

4 EH Antenna – An Example Located at Eatonton, Georgia

5 What Are The Defining Parameters Of An EH Antenna? ___________________________________________________________________________________________________ » Small Size

6 What Are The Defining Parameters Of An EH Antenna? ___________________________________________________________________________________________________ » Small Size »+ Low Height

7 What Are The Defining Parameters Of An EH Antenna? ___________________________________________________________________________________________________ » Small Size »+ Low Height »+ No Radials Required

8 EH ANTENNAS ARE DIPOLES

9 A 20 Meter EH Antenna

10 What Are The Defining Parameters Of An EH Antenna? ___________________________________________________________________________________________________ » Small Size »+ Low Height »+ No Radials Required »+ Broad Bandwidth

11 What Are The Defining Parameters Of An EH Antenna? ___________________________________________________________________________________________________ » Small Size »+ Low Height »+ No Radials Required »+ Broad Bandwidth »+ High Efficiency

12 What Are The Defining Parameters Of An EH Antenna? ___________________________________________________________________________________________________ » Small Size »+ Low Height »+ No Radials Required »+ Broad Bandwidth »+ High Efficiency »+ Low EMI

13 What Are The Defining Parameters Of An EH Antenna? ___________________________________________________________________________________________________ » Small Size »+ Low Height »+ No Radials Required »+ Broad Bandwidth »+ High Efficiency __________________________________________________________________________________________________________ »= A Great Antenna for Hams »+ Low EMI

14 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

15 QUESTION #2 – HOW DOES IT WORK? E FIELD H FIELD HIGH CURRENT

16 The Evolution Of The EH Antenna L+L NETWORK C1 C2 L1 L2 Phasing Coil Coax

17 The Evolution Of The EH Antenna L+T NETWORK Coax C1 C2 L1 L2 Phasing Coil

18 The Evolution Of The EH Antenna *STAR* EH ANTENNA COAX CYLINDER TUNING COIL PHASING COIL CYLINDER REACTANCE COIL

19 EH Antenna Analysis Program

20 Measuring 3 dB Resistance Definition Q=X L /R=F 0 /BW Therefore: R = BW*XL/ F0 Radiation Resistance = 3 dB Resistance – Loss Resistance

21 EH Antenna Analysis Program

22 C = 0.55*L/D*D *D

23 EH Antenna Analysis Program

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25 EH *STAR* ANTENNA COAX CYLINDER TUNING COIL PHASING COIL CYLINDER REACTANCE COIL

26 ROLL YOUR OWN EH ANTENNA STEP 1- OBTAIN TEST EQUIPMENT SIGNAL GENERATOR – FIELD STRENGTH METER – VSWR BRIDGE – IMPEDANCE BRIDGE (NICE)

27 PREFERRED TEST EQUIPMENT

28 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

29 COAX CHOKE

30 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

31 75 METER EH ANTENNA

32 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

33 75 METER TUNING COIL

34 ROLL YOUR OWN EH ANTENNA STEP 4 B - TUNE THE ANTENNA PLOT IMPEDANCE or COMPARE MAX RADIATION AND MINIMUM VSWR FREQUENCIES

35 IMPEDANCE WITHOUT REACTANCE COIL

36 ROLL YOUR OWN EH ANTENNA STEP 4 - TUNE THE ANTENNA C – INSTALL SOURCE COIL D – ADJUST FEED FOR 50 OHMS E – RECORD IMPEDANCE PLOT

37 IMPEDANCE WITH REACTANCE COIL 3 dB Bandwidth = 269 KHz

38 EH Antenna Analysis Program

39 HEIGHT VS. RADIATION ALONG THE GROUND.

40 WEB SITE www/eh-antenna.com


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