1. Transmission Lines VE3KL
An Overview of Transmission Line History
Some Theory
Cable Measurements
Oliver Heaviside
Invented Coax Cable
Patent No. 1407, dated 6th April
Published Telegraphers’ Equation 1885
E Layer (co-predictor)
Kennelly–Heaviside layer
4/26/2017
David Conn VE3KL

2. History leading to the Telegraphers Eqn.
Presentation Outline
History leading to the Telegraphers Eqn.
Basic theory…… defines how we measure and maintain cables
Measurements of Zo and VF….hands-on
Trouble Shooting Cable Problems
A mission statement from Lee De Forest
4/26/2017
David Conn VE3KL

3. History
1850: First submarine cable across the English Channel: England to France.
It was simply a copper wire coated with gutta-percha, without any other protection.
1855: Lord Kelvin; diffusion model of the current in a submarine cable….R/C only…like heat transfer….leading to the answer
Red Experiment Blue Theory
A method that you can use easily to evaluate your own noise environment
A method that you can use to evaluate the quality of the ionosphere at any give time.
Some methods to control received noise
The Shannon Hartley limits
4/26/2017
David Conn VE3KL

4. History The investor,chief engineer and foreman ? 4/26/2017
A method that you can use easily to evaluate your own noise environment
A method that you can use to evaluate the quality of the ionosphere at any give time.
Some methods to control received noise
The Shannon Hartley limits
4/26/2017
David Conn VE3KL

5. History
1858: Trans Atlantic Submarine Telegraph Cable…. Western Ireland to Heart's Content in eastern Newfoundland.. Not successful..plagued with problems
0.1 WPM Morse Code
A method that you can use easily to evaluate your own noise environment
A method that you can use to evaluate the quality of the ionosphere at any give time.
Some methods to control received noise
The Shannon Hartley limits
4/26/2017
David Conn VE3KL

6. History 0.1 WPM 1858 New York Celebration
After the first messages were transmitted over the Atlantic Cable in August 1858 between Valentia, Ireland, and Trinity Bay, Newfoundland, September 1st was declared as the official day of celebration in New York City.
0.1 WPM
A method that you can use easily to evaluate your own noise environment
A method that you can use to evaluate the quality of the ionosphere at any give time.
Some methods to control received noise
The Shannon Hartley limits
4/26/2017
David Conn VE3KL

7. History
1873: Maxwell publishes "Treatise on Electricity and Magnetism“: Four Mathematical Equations form the basis of all modern transmission lines and wave propagation.
1880: Heaviside Invents the Coaxial Cable
1885: Heaviside published the first papers that described his analysis of propagation in cables and the modern form of the Telegrapher’s Equation.
A method that you can use easily to evaluate your own noise environment
A method that you can use to evaluate the quality of the ionosphere at any give time.
Some methods to control received noise
The Shannon Hartley limits
4/26/2017
David Conn VE3KL

8. History…theory Before/After experiments
1893: Heaviside Publishes book on Vector Calculus…(vectorial, vectorist’s)….easy to use in E/M applications
1950: First submarine cables using coax and repeaters.
A method that you can use easily to evaluate your own noise environment
A method that you can use to evaluate the quality of the ionosphere at any give time.
Some methods to control received noise
The Shannon Hartley limits
4/26/2017
David Conn VE3KL

9. History
: Transatlantic No. 1 (TAT-1) was the first transatlantic telephone system. Scotland to Newfoundland.
Thirty six telephone channels. Coaxial Cable, Vacuum tubes and Repeaters
A method that you can use easily to evaluate your own noise environment
A method that you can use to evaluate the quality of the ionosphere at any give time.
Some methods to control received noise
The Shannon Hartley limits
4/26/2017
David Conn VE3KL

10. History 1960’s: Photograph of a Repeater Repeater Equalizers
Custom Designed on the Ship
Measure ship to shore frequency response
Use a slide rule to design an equalizer
Build the equalizer on site
Put into repeater box.
Drop over the side!
A method that you can use easily to evaluate your own noise environment
A method that you can use to evaluate the quality of the ionosphere at any give time.
Some methods to control received noise
The Shannon Hartley limits
4/26/2017
David Conn VE3KL

11. History Modern Cables use Fibre Optics 4/26/2017 David Conn VE3KL
A method that you can use easily to evaluate your own noise environment
A method that you can use to evaluate the quality of the ionosphere at any give time.
Some methods to control received noise
The Shannon Hartley limits
4/26/2017
David Conn VE3KL

12. Oliver Heaviside: Telegrapher’s Equations
History
Oliver Heaviside: Telegrapher’s Equations
Leads directly to:
Waves, Velocity of Light
Characteristic Impedance, Zo
Vf, SWR, ρ, Losses, Phase
Transmission Line Loading
Smith Chart
A method that you can use easily to evaluate your own noise environment
A method that you can use to evaluate the quality of the ionosphere at any give time.
Some methods to control received noise
The Shannon Hartley limits
4/26/2017
David Conn VE3KL

13. Coaxial Cable Basics Characteristic Impedance : a complex number
Outer Diameter
Resistance R [Ohms per metre]
Inductance L [Henrys per metre]
Conductance G [Mhos per metre]
Capacitance C [Farads per metre]
Inner Diameter
Characteristic Impedance : a complex number
A method that you can use easily to evaluate your own noise environment
A method that you can use to evaluate the quality of the ionosphere at any give time.
Some methods to control received noise
The Shannon Hartley limits
4/26/2017
David Conn VE3KL

14. Coaxial Cable Frequency Response
Outer Diameter
Resistance R [Ohms per metre]
Inductance L [Henrys per metre]
Conductance G [Mhos per metre]
Capacitance C [Farads per metre]
Inner Diameter
A method that you can use easily to evaluate your own noise environment
A method that you can use to evaluate the quality of the ionosphere at any give time.
Some methods to control received noise
The Shannon Hartley limits
4/26/2017
David Conn VE3KL

15. Coaxial Cable Basics Attenuation Constant α Outer Diameter
Inner Diameter
Resistance R [Ohms per metre]
Inductance L [Henrys per metre]
Conductance G [Mhos per metre]
Capacitance C [Farads per metre]
Attenuation Constant α
4/26/2017
David Conn VE3KL

16. Coaxial Cable Basics Velocity Factor Vf…velocity wrt. speed of light
Outer Diameter
Inner Diameter
Resistance R [Ohms per metre]
Inductance L [Henrys per metre]
Conductance G [Mhos per metre]
Capacitance C [Farads per metre]
c = velocity of light in a vacuum
Velocity Factor Vf…velocity wrt. speed of light
Used to cut phasing lines accurately: first time.
A method that you can use easily to evaluate your own noise environment
A method that you can use to evaluate the quality of the ionosphere at any give time.
Some methods to control received noise
The Shannon Hartley limits
4/26/2017
David Conn VE3KL

17. Time for a Break Let’s do some Measurements: Zo,VF
LC Meter
700 KHz
MFJ L/C/R/ρ
Ham Bands
Vector Z Meter
0.1 to 170 MHz
A method that you can use easily to evaluate your own noise environment
A method that you can use to evaluate the quality of the ionosphere at any give time.
Some methods to control received noise
The Shannon Hartley limits
4/26/2017
David Conn VE3KL

18. Measurements: Zo, VF Use an LC meter to measure
L and C of a 2 metre section of RG8-X
Measure L of the shorted cable
Measure C of the open cable
Use Excel, hand calculator or slide rule to calculate Zo, VF
A method that you can use easily to evaluate your own noise environment
A method that you can use to evaluate the quality of the ionosphere at any give time.
Some methods to control received noise
The Shannon Hartley limits
4/26/2017
David Conn VE3KL

19. Measurement Results Length = 2 metres
Measure Co of the open cable
Measure Ls of the shorted cable
A method that you can use easily to evaluate your own noise environment
A method that you can use to evaluate the quality of the ionosphere at any give time.
Some methods to control received noise
The Shannon Hartley limits
Ls = L = Ls/length =
Co = C = Co/Length =
Zo =
Vf =
4/26/2017
David Conn VE3KL

20. Measurements Requiring Vector Meters
Complex Characteristic Impedance
Zo = R + jX……. A complex number
Measure the impedance of a shorted cable, Zsc
Measure the impedance of an open cable, Zoc
Cable should be approximately 1/8 wavelengths long
A method that you can use easily to evaluate your own noise environment
A method that you can use to evaluate the quality of the ionosphere at any give time.
Some methods to control received noise
The Shannon Hartley limits
See reference 1 for details
4/26/2017
David Conn VE3KL

21. Example VE3KL Zo Measurements
RG8-X… 2 Metres 41 MHz
Zoc = j 39 Ohms
Zsc = 1.16 – j70 Ohms
Zo = 52.3 –j0.75 Ohms
A method that you can use easily to evaluate your own noise environment
A method that you can use to evaluate the quality of the ionosphere at any give time.
Some methods to control received noise
The Shannon Hartley limits
Aim 4170 Used
4/26/2017
David Conn VE3KL

22. Measurements Requiring Precision SWR/ρ Meters
Insertion Loss Measurement
Measure the ρ1 of a Loaded cable: ZL1 = 25 Ohms
Measure the ρ2 of a Loaded cable: ZL2=100 Ohms
Cable should be long……10 metres at 30 MHz
A method that you can use easily to evaluate your own noise environment
A method that you can use to evaluate the quality of the ionosphere at any give time.
Some methods to control received noise
The Shannon Hartley limits
See reference 2 for details
4/26/2017
David Conn VE3KL

23. Example Al1H Loss Measurements
RG-58A metres long
Frequency = 10 MHz
ρ1 = 0.316
ρ2 =
Loss = 0.35 dB
A method that you can use easily to evaluate your own noise environment
A method that you can use to evaluate the quality of the ionosphere at any give time.
Some methods to control received noise
The Shannon Hartley limits
MFJ 259B Meter Used
4/26/2017
David Conn VE3KL

24. Trouble Shooting Cable Problems
Perform a visual inspection for nicks and bulges.
2. Measure the DC resistance of a shorted cable.
High resistance indicates a corrosion problem
RG8-X has a total DC resistance of 25 Ohms
per 1000 metres
A method that you can use easily to evaluate your own noise environment
A method that you can use to evaluate the quality of the ionosphere at any give time.
Some methods to control received noise
The Shannon Hartley limits
4/26/2017
David Conn VE3KL

25. Trouble Shooting Cable Problems
3. Place a 25 Ohm load on the cable and measure SWR
If the cable loss = 0 dB, then SWR = 2.0
If cable loss = 1.0 dB, then SWR = 1.72
A 50 Ohm load does very little for loss measurements
Place a 50 Ohm load on the cable
Measure the SWR over a broad frequency range
to determine if the connectors are working properly.
A large band pass ripple indicates poorly assembled
connectors
A method that you can use easily to evaluate your own noise environment
A method that you can use to evaluate the quality of the ionosphere at any give time.
Some methods to control received noise
The Shannon Hartley limits
4/26/2017
David Conn VE3KL

26. TL Details AC6LA 4/26/2017 David Conn VE3KL
A method that you can use easily to evaluate your own noise environment
A method that you can use to evaluate the quality of the ionosphere at any give time.
Some methods to control received noise
The Shannon Hartley limits
4/26/2017
David Conn VE3KL

27. VY 73 Dave VE3KL Lee De Forest
“If you haven't a hobby--get one. Ride it. Your interest and zest in life will triple. You will find a common ground with others--a joy in getting together, in exchange of ideas --which only hobbyists can know.
Wireless is of all hobbies the most interesting. It offers the widest limits, the keenest fascination, either for intense competition with others, near and far, or for quiet study and pure enjoyment in the still night hours as you welcome friendly visitors from the whole wide world.”
Lee De Forest
4/26/2017
David Conn VE3KL

28. References TCA Jan/Feb 2011 VE3KL column TCA Mar/Apr 2011 VE3KL column
Measuring Cable Loss AL1H QEX May/June 2005
Transmission Line Zo vs. Frequency
N6GCE (
TL details
Coaxial Cable History:
Coaxial Cable Time
A method that you can use easily to evaluate your own noise environment
A method that you can use to evaluate the quality of the ionosphere at any give time.
Some methods to control received noise
The Shannon Hartley limits
4/26/2017
David Conn VE3KL