portable hf antennas - kj6vu · portable hf antennas think like a backpacker ... two common wire...
TRANSCRIPT
PackTenna www.packtenna.com
Portable HF AntennasThink Like A Backpacker
George - KJ6VU
PackTenna www.packtenna.com
WWW. HAMRADIO360 .COM
PODCAST
WWW. PACKTENNA .COM
PackTenna www.packtenna.com
www.KJ6VU.com
PackTenna www.packtenna.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
PackTenna www.packtenna.com
PackTenna www.packtenna.com
PackTenna www.packtenna.com
PackTenna www.packtenna.com
Popular Portable HF Antennas…
PackTenna www.packtenna.com
PackTenna
PackTenna www.packtenna.com
PackTenna
PackTenna www.packtenna.com
Just Throw A Wire Up In A Tree…
PackTenna www.packtenna.com
Fiberglass Mast
26” 32.5’
PackTenna www.packtenna.com
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
PackTenna www.packtenna.com
Feed Points and Chokes1:1 Balun
Feedpoint9:1 UNUNFeedpoint
In-LineCurrentChoke
Inverted VeeGround Plane
Dipole
End-Fed WireAny Hi-Z Antenna End-Fed Wire
PackTenna www.packtenna.com
“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
PackTenna www.packtenna.com
Next Project…
even smaller …
5-1/2”
The PackTenna
MINI
PackTenna www.packtenna.com
ELECTRICAL
DESIGN
PackTenna www.packtenna.com
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)
PackTenna www.packtenna.com
OK, But What… ???!!???
• What kind of antenna design?
• What materials?
• What bands?
PackTenna www.packtenna.com
Wire Antenna Basics
Dipole
Inverted Vee
Ground Plane
End-Fed Random Wire
End-Fed Half Wave
XXX
PackTenna www.packtenna.com
Center Fed Half Wave Dipole
72 Ohms
½ wavelength
PackTenna www.packtenna.com
Off Center Fed Half Wave Dipole
200 Ohms
½ wavelength
PackTenna www.packtenna.com
End Fed Half Wave
4,000 Ohms
½ wavelength
PackTenna www.packtenna.com
Two Common Wire Antennas
End Fed Random Wire
with a 9:1 UNUNEnd Fed Half Wave
with 50:1 UNUN
1935
PackTenna www.packtenna.com
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)
PackTenna www.packtenna.com
50:1
7:1 Turns =
49:1 Impedance
2450 Ohms : 50 Ohms
Z = T2
Impedance = Turns Ratio Squared
PackTenna www.packtenna.com
MECHANICAL
DESIGN
PackTenna www.packtenna.com
Design Goals
• Combine Wire Winder + 9:1 + Wire
• Make it smaller
PackTenna www.packtenna.com
Make It Small
5-1/2”
PackTenna www.packtenna.com
PT Mini PCB
PackTenna www.packtenna.com
Same PCB
Different
Torroids
50:1 UNUN 9:1 UNUN
PackTenna www.packtenna.com
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”
PackTenna www.packtenna.com
9:1 Toroid Core
A
B
C Each time the wire passes through the core it is “1 turn”
A
PackTenna www.packtenna.com
FIELD
TESTING
PackTenna www.packtenna.com
20m End Fed Half Wave Dimensions
31’ 3”
50:1 UNUN
PackTenna www.packtenna.com
20m End Fed ½ Wave
PackTenna www.packtenna.com
40m & 20m End Fed Half Wave Dimensions
32’ 9”
50:1 UNUN
4’ 10”
51 turns#24 on 1” OD PVC
PackTenna www.packtenna.com
20m/40m End Fed ½ Wave Coil
PackTenna www.packtenna.com
Use S-Clips and Banana Connector To
Customize Your Setup
32’ 9”
50:1 UNUN
4’ 10”
51 turns#24 on 1” OD PVC
51 turns#24 on 1” OD PVC
31’ 3”
PackTenna www.packtenna.com
20m/40m End Fed ½ Wave
PackTenna www.packtenna.com
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
PackTenna www.packtenna.com
½ Wave
counterpoise
PackTenna www.packtenna.com
PackTenna www.packtenna.com
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.
PackTenna www.packtenna.com
Thank You