SimSmith Transmission Line k Terms

k0
  1. Mismatched DC loss in dB per 100 feet.
     
  2. Approximation: dB ~= 10 * log((Zo + DCR) / Zo)
    First Plot Green Line
    Bottom SimSmith k0 DCr Example
     
  3. Defined as: dB = 20 * log((Zo + DCR/2) / Zo)
     
  4. Can Be measured using 2-Port VNA with VNA Impedance matching Zo,
    First Plot Black Line
     
  5. Close match to SimSmith Load = Generator = Zo,
    First Plot Black Points
     
  6. Difficult to measured using matched loss techniques such as Zoc Zsc,
    First Plot Blue Line and Points
     
  7. Requires low frequency measurements, below 400 kHz for RG-58 Type,
    First Plot Black/Red Line break at ~400 kHz
k1
  1. Wire loss in dB at 1 MHz per 100 feet
     
  2. Loss at frequency F in MHz = k1 * √F
     
  3. First Plot Red Line, .36 value
k2
  1. Dielectric loss in dB at 1 MHz per 100 feet
     
  2. Loss at frequency F in MHz = k2 * F
     
  3. First Plot Red Line, .022 value

Measurement Techniques

Published Data
  1. Plotting loss data,
    Plots of published Belden data
2-Port VNA S21
  1. Requires VNA match to Zo
    First Plot Black Line
Zoc Zsc
  1. Balanced Line requires Balun or Isolated VNA such as AA-600
     
  2. Transformer Balun behaves well,
    First Plot Blue Line
     
  3. Choke Balun may not be sufficient to eliminate antenna effects,
    First Plot Red Line deviates from loss line above 1 MHz
     
  4. Not valid at 1/4 wave multiples, requires removing outliers for plotting loss,
    First Plot Blue Line, 1/4 wave outliers from line
     
  5. SimSmith Evaluation Example
     
  6. Can not be used to measure k0 loss term, see above.