qrp-gaijin small transmitting loop calculator

Loop geometry

Loop shape Circle Square Rectangle

Loop diameter m

Loop side length m

Loop width m
Loop height m

Loop perimeter m
Loop area m^2
Number of turns

Loop conductor geometry

Conductor cross sectional shape Circular Rectangular

Conductor diameter mm

Conductor width mm
Conductor thickness mm

Equivalent round conductor diameter for RF resistance
Equivalent conductor diameter for loop inductance
Loop conductor inductance uH
Loop conductor material Aluminum Copper Custom
Loop conductor bulk resistivity Wm
Loop conductor loss multiplier (braid:4-16)

Tuning capacitor parameters

Length of capacitor connecting wires mm
Connecting wire cross sectional shape Circular Rectangular

Connecting wire diameter mm

Connecing wire width mm
Connecting wire thickness mm

Equivalent round conductor diameter for RF resistance
Connecting wire conductor material Aluminum Copper Custom
Connecting wire bulk resistivity Wm
Connecting wire loss multiplier (braid:4-16)
Capacitor model Hi-Q air+wiper Lo-Q air+wiper Custom
Frequency-independent fixed loss ohms
Frequency-dependent dielectric loss coefficient
Frequency-dependent metal (Joulean) loss coefficient
Tuning capacitor min pF
Tuning capacitor max pF

Possible future parameters

Loop conductor loss due to proximity effect
Loop conductor loss due to inter-turn capacitance
Loop conductor loss due to very thin wall
Connecting wire loss due to very thin wall
Inductance calculation of capacitor connecting wire
Flat-conductor inductor losses per G3RBJ

Tuning range

Minimum frequency
Maximum frequency

Graph parameters

Graph minimum frequency
Graph maximum frequency

Disclaimer

No claim of accuracy is made for this calculator. Do not use this calculator for any purpose except entertainment. Refer to the references and perform your own calculations to see if they agree with this calculator's output.

Notes on usage of this calculator

This calculator allows calculation and visualisation of loss components in a small transmitting loop. Unlike other small loop calculators, this loop calculator has a number of unusual features:

• Support for multi-turn loops (but see notes below)
• Choice of copper, aluminum, or custom conductor material
• Support for flat (rectangular cross-section) conductors using W9CF's analytic formulas for RF resistance and self-impedance (see references) 
• Support for braided conductor loss using a fixed multiplier between 4 and 16 to represent increased losses through wire-to-wire pressure connections in braid
• Inclusion of capacitor loss including fixed, dielectric, and metal losses, as per G3RBJ's model (see references); two capacitor models pre-defined, with custom parameters allowed
• Inclusion of connecting wire loss (connecting capacitor and loop)
• Visualisation of all loss components in both normalised and absolute-value graphs.

Note that for multi-turn loops, the calculator does not include losses due to turn-to-turn proximity effect or turn-to-turn capacitance (circulating currents). The efficiency estimates for multi-turn loops will thus be optimistic.

The validity of W9CF's analytic formulas for rectangular cross-section conductors as used in small transmitting loops, especially multi-turn loops, is not clear.

Ground losses are not included.

References

• Radiation resistance of single- or multi-turn loop 
• Inductance calculations for single- or multi-turn loops of square, rectangular, or circular geometry
• Calculation of minimum RF sheet resistance
• Equivalent round conductor diameter for rectangular cross-section conductors
• Capacitor loss model