EH antenna project

By VE3RGW 2004

EH- original 10-30MHz

6uH 37pF

26pF 3uH

Upper cylinder8cm dia, 20cm long

Lower cylinderValue for 20m3uH #13AWG, 3cm dia, 10T6uH #13AWG, 3cm dia, 16TVC in form of 33pF+18pF fixed

Prototype for academic version

Upper cylinder

Cylinder spacing = diameter

Lower cylinderFerrite choke and phasing network

EH- LC 90deg fed VK version

3T 14T 14T

C1-150pf C2-50pf ( D leads E by 90deg.)(Peak at operating frequency)

Upper Cone (E)

Lower Plate (D)

Ground Plane

All windings on same 50mm T-200-2 toroid

90deg lag

L1 L2 L3

EH-Star antenna (L+T)

Ferrite or choke On 50ohm coaxial Feed coil Tune coil

C1 C2

Upper cylinder

Phase coil(3-6 deg)

Lower cylinder

EH-Link antenna (KE0VH)

Ferrite or choke On 50ohm coaxial Tune coil

Link coil

Upper cylinder

Lower cylinder

Prototype 1 verification model

2” tomato paste can

Phase line 2T (33-35cm wire length)

Foam spacer

2” PVC vacuum pipe

2” tomato paste can

Tune coil (14 AWG magnet wire)22T-11.5MHz, 20T-12.2MHz 17T-13.5Mhz, 16T-14.1MHz

Tap for coaxial core, 2T to ground(coaxial blade)RG58U coaxial

Ferrite choke

EH antenna (L only)

50ohm coaxial Feed coil Tune coil

C2 (150pF 2KV)

Upper cylinder

Phase coil(3-6 deg)

Lower cylinder

Coaxial choke

Cable between choke and C2 can be part of radiating element

Prototype 1 finalized model 26/Feb/2004

2” tomato paste can

Phase line 2T (33-35cm wire length)

Foam spacer

2” PVC vacuum pipe

2” tomato paste can

Tune coil (14 AWG magnet wire)22T-11.5MHz, 20T-12.2MHz 17T-13.5Mhz, 16T-14.1MHz

L2 removed150pF 2KV cap (C1)

Ground ring to coaxial and lower cylinder

Ferrite choke

VSWR verses Frequency

2.01.8

1.61.5

1.4 1.31.5

1.61.8

2.0

0.0

0.5

1.0

1.5

2.0

2.5

3.0

Frequency

VS

WR

13.95MHz 14.2MHz 14.4MHz

VSWR can lower to 1:1.15 with ground plane application

The device is extremely sensitive to surrounding capacitive related influence. VSWR differs as RF choke position of the coaxial feed cable changes. This indicated the device tends to use coaxial cable radiation. Condition Best VSWRNo choke 14.297MHz 1:1.2Choke 3” 14.198MHz 1:1.2Choke 36” 14.262MHz1:2.3

This indicated not much chance to use multiple cable kit to change operating band of the device. Yet calibrated working condition of the device has to be closely matched when used.

Prototype 2 verification model

6” Brass tube (1.4” inner Dia)

Phase line 1T (15cm wire length)

Foam spacer

1.25” PVC pipe (30” total length)

6” Brass tube (1.4” inner dia)

Tune coil (14 AWG magnet wire)Resonance (Dip check)25T-12Mhz, 25T-13MHz20T-14MHz (Tight wind)12.5T-21Mz (Tight wind)9T-27-29MHz (length 1.5” to 1”)

Feed Coil (2T 0.3” from tune coil3T on top of tune coil for 27-29MHz

8T coaxial choke

1.5” space

1.5” space

Coil parameter (12MHz-29MHz for prototype 2)

+/- 50KHz+/-50KHz<3”<3”<3”Bandwidth

Resonance

Coil length

Turns

Band 20mM5

14.1MHz13.9MHz19.7Mhz19.5MHz19.1MHz

TightTightTBATBATBA

22.5T23T26T28T30T

Bandwidth

Resonance

Coil length

Turns

Band 15mM7M6

21.0MHz20.5MHz19.7Mhz18.5MHz17.0MHz

TightTightTightTightTight

11T12.5T12T14.5T15.5T

+/- 0.5MHz+/- 0.5MHz+/- 0.5MHz+/- 0.15MHzBandwidth

Resonance

Coil length

Turns

Band 10m-B10m-A11mM8

29.0MHz28MHz26.5Mhz22MHz21.5MHz

1.5” long1.3” long1.0” longTightTight

9T9T9T10T10.5T