Shared operating conditions below. Categories preserve your tuner settings. Broadband multisection transformers and analyzer file import are planned, not available in this release.
Manual tuner — drag each dial, turn mouse wheel, or use the sliders
C1
L
C2
Live results — transmitter looking into tuner
*Power-wave Γ = (Zin − Zs*) / (Zin + Zs), where Zs* is source conjugate and source resistance is positive. Reflected fraction = |Γ|²; generalized SWR = (1+|Γ|)/(1−|Γ|). These are source-referenced match metrics. For a reactive source, do not interpret them as literal voltage-wave SWR or reflected power on a 50 Ω transmission line. The Smith chart remains normalized to source resistance Rs. Finite-Q component model.
Smith chart and frequency sweepShow / hide
Input impedance on Smith chart
Chart normalized to source resistance. Orange trace = complete network input across the sweep; gray dots = complete network input at measurement frequencies. Stage markers are at F₀; no connecting path is implied.
Frequency sweep — custom / selected band / analyzer span
Fixed-load mode follows the chosen custom range or amateur-band preset (including margin). Analyzer mode uses only the measured endpoints, without extrapolation. Active components stay fixed; green marker is F₀ when within the span.
Network choices — compare mechanical arrangementsShow / hide
Choose the arrangement that fits
Compare both series-C / shunt-L orientations and the π network using the same source, load, frequency, transformer and limits. Exact solutions and best-found LC/CL compromises are distinguished. Compare the residual impedance, SWR, delivered power and loss, then choose for mounting, grounding and shaft access. Comparing leaves the working tuner unchanged.
Coax Matching Lab — stubs, single L/C and line transformersShow / hide
Coax matching — independent design workspace
Uses the entered source and raw antenna impedance at F₀ (before any active transformer). TX → matching junction → coax → antenna. All line lengths are electrical design lengths converted using velocity factor; ideal lossless coax and components. No main tuner settings are changed.
Quarter-wave line uses the main coax velocity factor. Lengths are from the antenna reference plane to the junction, not additional cable on top of an existing feedline. Include connector and termination effects when trimming.
An open stub is open at its far end; a shorted stub joins inner conductor to shield at its far end. Both are shunt branches at the junction. Series L/C is in the signal path; shunt L/C connects junction to return. Exact solutions are at F₀ only. Ideal SWR does not establish cable loss, voltage/current ratings, bandwidth, or common-mode performance.
Design Evaluation — comparison chartShow / hide
Design Evaluation — electrical match versus practical construction
A quick comparison across the three available network arrangements and a small set of representative ideal transformer options. The first row always records the current manual setup; other rows are numerically optimized at F₀. COMPARE does not alter the main tuner.
Press COMPARE DESIGNS. The table shows modeled power, stress and sweep coverage with all networks assessed under the same conditions.
Electrical ratings and losses are modeled estimates, not measured hardware performance. Transformer losses, saturation, winding insulation, radiation efficiency, stray reactances and mechanical fit are not known. At VHF/UHF, lumped-element assumptions need special caution. No configuration is installed until you press USE.
Matching Advisor — transformer optionsShow / hide
Matching Advisor — preliminary impedance transformation
Evaluate matching in the selected network versus an ideal impedance transformer / unun placed between the selected network and antenna. For a reduction ratio N:1, the tuner-side load is Z antenna / N; for a step-up, N · Z antenna. Both resistance and reactance are transformed. A balun is needed only when balanced-to-unbalanced conversion is required. No transformer core, copper, common-mode or voltage losses are modeled yet.
Step 1: Press COMPARE OPTIONS. The advisor automatically tests direct matching plus both directions for 4:1, 9:1 and 16:1. Step 2: Press USE on a result you like. Comparing never adjusts the tuner.
Active: direct network (1:1).
The comparison uses the same capacitor limits and inductor Q as the tuner, and searches feasible ideal solutions in the selected network. Reported load power and network losses include the model's capacitor and inductor losses but not transformer losses. Each candidate is re-evaluated with finite Q after its ideal initial tuning. This is a design screening tool, not proof of transformer feasibility.
Press COMPARE OPTIONS to test the selected network directly and both step-up and step-down transformations. Press USE only when you want to change the working tuner.
Peak RF voltage across active componentsShow / hide
RF voltage stress — PEAK values emphasized
The readings are across each active component. In an L-network, C is series-connected and L is shunt-connected at the selected end. Large amber numbers are RF PEAK voltage; smaller readings are RMS. Peak is sine-wave RF peak, not peak-to-peak. Compare peak voltage to the actual capacitor manufacturer's RF voltage rating and allow margin for arcing, humidity, spacing, and load changes.
Voltages are measured across each component, including the phasor difference across a series component. A shunt component is measured to the common return. Ratings are not assumed. Large reactive currents and voltages may occur even with a 1:1 input match.
Capacitor peak-voltage ratingsShow / hide
Capacitor RF PEAK voltage limits
Comparison is with sinusoidal PEAK voltage, not peak-to-peak. Ratings are user-entered, not manufacturer-verified; sufficient safety margin is essential. Approaching the rating is not a guarantee against arcing.
Component Q and estimated lossesShow / hide
Real component model — Q and losses
L1 is modeled as an ideal inductor with series winding resistance derived from Q at F₀. Its resistance stays constant over a sweep (first-order model). Capacitor losses are modeled as shunt conductance with constant capacitor Q. All Q values must be positive.
Estimated losses only: no core saturation, ferrite frequency curves, stray reactances, heating-driven Q changes, contact losses or transmission-line effects. At high frequencies this simplified model may be inadequate.
Analyzer measurements (4–5 readings)Show / hide
Antenna analyzer readings — frequency-dependent load
Enter 4 or 5 analyzer readings. Values are antenna impedance at the same reference plane, in MHz, Ω, Ω. They must increase in frequency, with positive R. The matching knobs and source stay fixed over the sweep. Between readings, the program linearly interpolates R and X; it never extrapolates beyond the first and last reading. Use closely spaced measurements near sharp resonances.
Measured mode uses interpolated load impedance at F₀ for matching and stress calculations. Source impedance is still assumed constant across the sweep. These example readings are invented for demonstration, not measurements of an antenna.
Frequency sweep limits and band presetsShow / hide
Sweep frequency range — unrestricted or amateur-band preset
Custom span: 6.950–7.350 MHz. Choose a band preset or enter any start/stop frequencies.
Presets are convenience ranges for U.S. amateur allocations, not operating restrictions. Custom spans support commercial and experimental frequencies. In analyzer mode the plot always uses measured endpoints, without extrapolation; selection here applies to the fixed-load model only. At VHF/UHF, ideal lumped-element assumptions can become unrealistic due to stray reactances and self-resonance.
Capacitor travel limitsShow / hide
Capacitor travel limits
Separate limits for each variable capacitor. AUTO MATCH and manual knobs obey them.
Operating notesShow / hide
Operating notes
AUTO MATCH solves both algebraic branches of the selected L-network, or sweeps C2 for π solutions, and finds feasible settings within the selected capacitor travel limits and 0.05–40 µH. Positive source and load resistance required. If no exact ideal LC/CL solution exists inside the selected component limits, a constrained best-found result is offered with residual SWR, impedance, delivered power and loss. The π solver still reports out of range when it finds no feasible ideal solution. Source is a Thevenin-equivalent impedance and target is its complex conjugate. Computed voltage and delivered-power readings assume sinusoidal steady-state source available power and component Q and modeled losses. In REVERSE TUNE the algorithm searches the specified frequency range and identifies local minima of input mismatch with active components fixed. With single-point source/load entries, both impedances are assumed frequency-independent. Transformer model is an ideal impedance scaling only; no transformer winding or core losses, parasitics or physical antenna bandwidth modeling are included. For π candidates the advisor scores modeled delivery, mismatch and capacitor stress. L-network solutions are ranked by mismatch. These estimates do not guarantee maximum real-world efficiency.
Transmission Line Lab
TX → uniform coax → antenna. Uses the raw antenna impedance and available source power above, without the lumped tuner or transformer. Compare three standard impedances at the same physical length. Enter cable data from its datasheet; default VF and attenuation are illustrative, not cable specifications.
| Standard Z₀ | Velocity factor | Matched loss (dB / 100 ft at F₀) |
|---|---|---|
| 50 Ω | ||
| 75 Ω | ||
| 93 Ω |
Peak voltage along coax (V)
RMS current along coax (A)
Source-referenced SWR across selected sweep
Uniform line with real Z₀ and constant velocity factor. Attenuation is held constant over the sweep as a first-order approximation. Power-wave SWR is a match index for complex sources, not literal cable SWR. Cable loss excludes connectors and common-mode effects. Voltage/current maxima are sampled estimates; compare to manufacturer ratings. Analyzer mode uses only measured frequencies.
Feed-point de-embedding — remove the feedline
Enter the impedance measured at the shack end of a known uniform coax. The calculation removes the modeled line to estimate the antenna feed-point impedance at F₀ (shared frequency above). The main tuner is not changed. No VNA connection is required.
Enter actual cable specifications and measurement.
Length comparison shows how uncertainty affects the inferred impedance. At high mismatch or large attenuation, inversion can amplify measurement errors; non-passive results are rejected. A lossless line rotates Γ but does not change its magnitude relative to its own Z₀. A different Z₀ or additional matching element can change the source match. The model assumes a uniform line; connectors, common-mode currents and calibration errors are not removed. No individual technical support provided.
Optimum Feedline Length
Enter the antenna feed-point impedance in Operating Conditions (not the shack-end reading). Compare practical cable lengths with or without a transmitter-side tuner. A lossless uniform cable rotates the impedance on a Smith chart but does not change SWR relative to its own Z₀. It can make the impedance easier for a tuner to match. All results are estimates at F₀; no settings are changed by comparing.
Ranking: meets source match threshold and capacitor ratings first; then highest delivered power. Shortest and longest tested lengths are also shown for comparison. Cable voltage/current are sampled estimates, not safety ratings. The π tuner is re-solved at every tested length using its existing C/L limits and Q; no transformer is assumed. No exact π solution found does not rule out an approximate or other topology match.
Optional Smith chart — see what the line length does
The chart uses the selected coax Z₀ as its real reference. The curve shows the shack-end impedance before any tuner as cable length increases. Lossless lines follow a constant-|Γ| circle; attenuation moves the trace inward. The center is a match to the cable, not necessarily to the source. Colored markers identify comparison lengths.
Peak voltage along cable (V)
RMS current along cable (A)
Air-core Coil Designer
Single-layer copper solenoid, adapted from Larry's LC Resonance Lab V14. Compare winding geometries for the selected inductance. No changes to the tuner until you press USE Q.
Wheeler's formula uses mean winding radius, not bare form radius. Winding length is the axial span of the winding; pitch is approximated by length / turns. Fractional turns describe an estimated target; round or adjust and measure before construction. Skin-effect-only resistance excludes proximity effect, leads, contacts, self-capacitance and dielectric/core losses. Q is an optimistic estimate, not a rating. At VHF/UHF verify self-resonance and actual Q with a VNA. No individual technical support is provided.