portable hf antennas - kj6vu · portable hf antennas think like a backpacker ... two common wire...

PackTenna www.packtenna.com

Portable HF AntennasThink Like A Backpacker

George - KJ6VU


WWW. HAMRADIO360 .COM

PODCAST

WWW. PACKTENNA .COM


www.KJ6VU.com


My Personal Goals…

• Operate more HF

• Get out and hike more

• Improve my CW skills

• Build some cool stuff

• Obsess over a new project


Popular Portable HF Antennas…


PackTenna


Just Throw A Wire Up In A Tree…


Fiberglass Mast

26” 32.5’


1:1 Feed Point Balun

Holes for S-Clips- Antenna wire strain relief- Mounting

Mounting holes for mini-bungee cords

Vertical wire element jack

Horizontal or Veewire element jacks

Coax connector

Zip-tie holes to mount toroids


Feed Points and Chokes1:1 Balun

Feedpoint9:1 UNUNFeedpoint

In-LineCurrentChoke

Inverted VeeGround Plane

Dipole

End-Fed WireAny Hi-Z Antenna End-Fed Wire


“Think Like a Backpacker”

1. Weigh your stuff - Ounces add up to pounds.

2. Trim the fat: leave the kitchen sink at home.

3. Plan your trip: limit your contingencies.

4. Take the lightest possible item to do the job.

5. Simplify: take items that serve multiple functions.

6. Don’t just take a bunch of stuff: build a system.

7. Get back to the basics - don't over complicate things.

Backpacking Light 101“ By Ryan Jordan"Seven Steps to Enlightenment“www.backpackinglight.com


Next Project…

even smaller …

5-1/2”

The PackTenna

MINI


ELECTRICAL

DESIGN


Portable HF Antenna Challenges

• Needs to be big: 16’ to 66’ (20m to 80m)

• Needs some sort of support

• Needs to be light weight

• Needs to be compact

Answer…

Wire + Mast (or tree)


OK, But What… ???!!???

• What kind of antenna design?

• What materials?

• What bands?


Wire Antenna Basics

Dipole

Inverted Vee

Ground Plane

End-Fed Random Wire

End-Fed Half Wave

XXX


Center Fed Half Wave Dipole

72 Ohms

½ wavelength


Off Center Fed Half Wave Dipole

200 Ohms

½ wavelength


End Fed Half Wave

4,000 Ohms

½ wavelength


Two Common Wire Antennas

End Fed Random Wire

with a 9:1 UNUNEnd Fed Half Wave

with 50:1 UNUN

1935


9:1 UNUN

The turns ratio is 3:1 for a transformation of 9:1.

The impedance is the square of the turns ratio (Z=T^2)


50:1

7:1 Turns =

49:1 Impedance

2450 Ohms : 50 Ohms

Z = T2

Impedance = Turns Ratio Squared


MECHANICAL

DESIGN


Design Goals

• Combine Wire Winder + 9:1 + Wire

• Make it smaller


Make It Small

5-1/2”


PT Mini PCB


Same PCB

Different

Torroids

50:1 UNUN 9:1 UNUN


50:1 Toroid Core

14 turns

2 turnsbifilar winding

AB

A

B

C

A/C wire length = 24”

C

Each time the wire passes through the core it is “1 turn”

A/B wire length = 6”


9:1 Toroid Core

A

B

C Each time the wire passes through the core it is “1 turn”

A


FIELD

TESTING


20m End Fed Half Wave Dimensions

31’ 3”

50:1 UNUN


20m End Fed ½ Wave


40m & 20m End Fed Half Wave Dimensions

32’ 9”

50:1 UNUN

4’ 10”

51 turns#24 on 1” OD PVC


20m/40m End Fed ½ Wave Coil


Use S-Clips and Banana Connector To

Customize Your Setup

32’ 9”

50:1 UNUN

4’ 10”



31’ 3”


20m/40m End Fed ½ Wave


End Fed All Band Random Wire Dimensions

29”

9:1 UNUN

Length =Not a ¼ wavelength or harmonic on any bandGood choices: 29’ 35.5’ 41’ 58’ 71’ 84’TUNER


½ Wave

counterpoise


Wire WrappingWrap the wire using a “figure 8” pattern.Wrap 20’ (½ the wire) on one side then 20’ (half the wire) on the other side.


Thank You

portable hf antennas - kj6vu · portable hf antennas think like a backpacker ... two common wire...

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