1. Joe Horanzy AA3JH April 4th, 2013 K3DN Presentation
Memoirs of DXCC
I made a composite of all material I studied and learned from various sources to prevent paralysis of analysis.
My background.
Some of this is fundamental, but I build upon the data
I was trying to find a good title to my presentation. Just antennas, no. It doesn’t give it justification. When I first started, I bought a G5RV and tossed it in the attic. The only thing I was able to do is to talk to a local few rag chewers on 80 meters and set off the house alarm. I was unable to talk to any one in Europe. So, I started studying the fundamentals. I had to weed out all the hype, snake oil marketing out there and piece data from many locations and compile the data until it all made sense.
Joe Horanzy AA3JH
April 4th, 2013 K3DN Presentation

2. Agenda Awards Impedance Measuring Equipment Picking the Antenna
Antenna components with construction tips and theory
Putting it all together
Multiband
Getting more gain
Simulation tools
Vertical Moxon
Future plans

3. Awards

4. Open to all license classes
10 meter progress
Open to all license classes

5. Impedance Z = R + jX Where R = natural antenna and grd loss resistance
X = total antenna reactance combination of capacitance and inductance
Reactance (X) is your enemy. Why?
A reactive component alternately absorbs energy from the circuit and then returns energy to the circuit. A pure reactance will not dissipate any power.

6. Impedance You can’t go by just impedance (Z) alone.
A Z of 50 of resistance vs. a Z of 50 reactance is very different.
A Z of 50 of pure resistance = SWR 1:1
A Z of 50 of reactance = SWR >20:1 !
A Z of 100 of pure resistance = SWR 2:1
A Z of 100 of reactance = SWR >20:1 !

7. Impedance
“So I have residual reactance, so what? I’ll tune it out with my trusty antenna tuner in the shack.”
#1 Remove all reactance at the antenna.
Matching at the transceiver only satisfies the connection between the transceiver and the tuner.
Loss in the cable dramatically increases

8. Impedance

9. Measuring Equipment

10. Picking the antenna
Main Object: Get on HF to communicate around the world (DX) with an antenna that is:
Simple
Low maintenance
Ease of construction
Readily available components
Stealth
Low cost
But very efficient and effective.

11. The Vertical Antenna Few components, low cost. Easy to hide.
Easy to make multiband.
Has low take off angle, great for DX
DX is not line of sight. Polarization doesn’t matter.
Vertical dipoles: don’t need ground radials but is ½ l and end fed requires matching.
¼ wave vertical: only ¼ l high (half the V/D height), no balun required, but requires ground radials.

12. The ¼ Wave Vertical
They get a bad name because many don’t radiate from improper installation from:
Ineffective ground plane / counterpoise
Residual reactance, not resonating.
Improper trap design causing excess loss.
Anytime you move from the basic antenna, there will always be compromises either through power loss and/or bandwidth limitations.

13. The ¼ Wave Vertical

14. The ¼ Wave Vertical Single Band How high: *235/ Freq (Mhz)
example: for 14.1 Mhz 20 meter band
235 / 14.1 = 16.7 feet.
*235 is from: 300 M meter/sec (speed of light) X 95% (speed of light slows down in wire) /4 (1/4 wave) X 3.3 ft/m (convert to ft)

15. The ¼ Wave Vertical
Ground system

16. 2. How many ground radials
why?
Soil has high resistance.
To reduce ground resistance
as much as possible.
Any power that is dissipated
in the soil weakens the signal.
As they say: heating up the worms
From Arrl Antenna handbook

17. Ground loss
Rr: Antenna’s natural radiations resistance: is the virtual resistance
in transferring the energy to produce the radio wave.
For ¼ wave vertical antennas, it’s about 36 ohms. (note: SWR 1:4)
Rg: Ground loss resistance.
Rtotal = Rr + Rg  Z = Rtotal + jX
Antenna efficiency (%) = (Rr / Rtotal ) x 100
For example: say ground resistance is 14 ohm, then
Rtotal = = 50 ohms, great SWR but…
Efficiency = 36/50 x 100 = 72 percent
If 100 W is transmitted only 72 watts is being radiated.
xmit
Rr: Radiated resistance
Rg: Ground resistance
Tell how can you measure ground resistance…..
From Arrl Antenna handbook

18. Ground radials

19. The ¼ Wave Vertical 2. Ground radials length:
.25 l or greater. For multiband, use random lengths.
3. Wire size:
12 or 14 AWG
4: Type:
Stranded for vertical
Solid for ground radials
5: Insulated: Doesn’t matter.

20. COMPONENTS OR

21. Putting it all together
Bungee cord
20M trap

22. Ground Connection

23. Ground Connection
Close up

24. Multiband Vertical
Resonate Traps:

25. Trap:
Inductor/
HV Cap

26. Multiband Vertical
Another approach
Fan Vertical

28. Contacts made with home brew fan vertical antenna (40 to 10 meter)
No amplifier.

29. Summary Cancel out all reactance at the antenna.
Install best ground radials as possible to keep ground resistance low as possible.
Keep all component loss in the system to a minimal.
Use good coax, RG213 or better, and ensure all connections are soldered correctly (beware of HRO).

30. Gain
Dbi : Gain measured in relation to an isotropic radiator, an imaginary antenna in freespace.
Dbd : is a reference to a dipole antenna in free space and is simply Dbi
Dipole in freespace can have 2.15 Dbi gain or 0 Dbd.
From Arrl Antenna handbook

31. Vertical ¼ wave vs. Horizontal Dipole
Azimuth Pattern: Antenna radiation pattern viewed from above.

32. Vertical ¼ wave vs. Horizontal Dipole
Elevation Pattern: Angle of maximum radiation in relation to the ground. Lower the better for DX.

33. Height above ground of a Horizontal antenna to be effective
“Sky shooter” Comparable to vertical Lowers angle even more
Bad for DX More gain than vertical Creates multiple lobes
Would require rotator

34. How to get gain out of my vertical?
Yagi style but vertical?

35. The Moxon Variation of the Yagi Compact than Yagi
Equivalent gain of a Yagi High front back ratio

36. The Moxon

37. Free simulation software

38. Free simulation software

39. Vertical Moxon
Simulated results

40. Horizontal Moxon
Simulated results

41. The Vertical Moxon

42. End Fed Matching Network
Pick permeability
too low: too much wire
too high: more loss
Self resonate secondary winding in band to prevent additional reactance (16T)
Measure Z at antenna input (2K)
Calculate turns ratio:
Calculate primary winding: 16/6.3 = 2.5 turns
Short secondary, measure primary Z, note reactance.
To cancel out the inductive reactance, put series capacitor with same reactance in series with the input of the primary.
Measure impedance
Determine permeability of ferrite
Turn ratio to get primary winding sqr (MI/Mo)
Short sec, read primary Z to add cap in series.

43. The Vertical Moxon

44. Future plans
Hex Beam

45. Future plans
Hex Beam

46. Future plans
Hex Beam

47. Thank you very much
DE AA3JH