Ham Radio Antenna Calculators
One hundred sixty-four antenna and component calculators covering every common — and plenty of uncommon — HF, VHF, and UHF antenna types — dipoles, Yagis, Moxon rectangles, cubical quads, delta loops, J-poles, end-fed half-waves, loading coils, traps, portable and mobile whips, classic named wire designs, phased beams and arrays, receive-only loops, and HOA/stealth builds. All calculations run in your browser with no data sent anywhere.
Quick Reference — Jump to a Calculator
164 calculators total, organized alphabetically in three groups below. Click any name to jump straight to it.
HF (105)
- 10 Meter Vertical Antenna
- 10m Half-Wave Dipole Antenna
- 12 Meter Vertical Antenna
- 12m Half-Wave Dipole Antenna
- 15 Meter Vertical Antenna
- 15m Half-Wave Dipole Antenna
- 160m Inverted-L Antenna
- 160m Vertical Antenna
- 17 Meter Vertical Antenna
- 17m Half-Wave Dipole Antenna
- 20 Meter Magnetic Loop Antenna
- 20 Meter Vertical Antenna
- 20m Half-Wave Dipole Antenna
- 20m Moxon Rectangle Antenna
- 30 Meter Vertical Antenna
- 30m Half-Wave Dipole Antenna
- 4-Square Vertical Array
- 40 Meter Vertical Antenna
- 40m Delta Loop Antenna
- 40m Half-Wave Dipole Antenna
- 60 Meter Vertical Antenna
- 60m Half-Wave Dipole Antenna
- 80 Meter Base-Loaded Vertical Antenna
- 80m Full-Wave Loop Antenna
- 80m Half-Wave Dipole Antenna
- 80m–10m EFHW Antenna for Fixed Station Use
- All-Band Doublet Antenna
- Antenna Gain dBd ↔ dBi Converter
- Antenna SWR Bandwidth and Q Calculator
- Antenna Trap LC Calculator
- Attic & Stealth Dipole Antenna
- AX1-Style Short Whip Coil Calculator
- Base Loading Coil Calculator
- Beverage Receive Antenna
- Bisquare Loop Calculator
- Bobtail Curtain Calculator
- Bruce Array Calculator
- Buddipole-Style Coil-Loaded Arm Calculator
- Buddistick-Style Vertical Coil Calculator
- Bugstick Mobile Whip Coil Calculator
- Carolina Windom Antenna
- CFA Starting-Size Calculator
- Classic Windom Leg Calculator
- Cobweb 5-Band Element Calculator
- Cubical Quad Element Calculator
- Double Bazooka Coax-Sleeve Calculator
- EFHW Antenna for SOTA and POTA
- EFHW Wire Length and UNUN Calculator
- EH Antenna Cylinder Size Calculator
- EWE Receive Loop Calculator
- Extended Double Zepp (EDZ) Calculator
- Fan Dipole Antenna
- Fixed-Coil Mobile Whip Calculator
- Flag Receive Loop Calculator
- Flagpole Vertical Calculator
- Folded Dipole Length Calculator
- Full Sloper Length Calculator
- Full-Wave Delta Loop Calculator
- Go-Kit EFHW Length Calculator
- Gutter-Mounted Stealth Wire Calculator
- Half-Square Antenna
- Half-Wave Dipole Length Calculator
- Hex Beam Antenna
- HF Magnetic Loop Antenna
- HF Receive Loop Antenna — Complete Construction Guide
- Inverted-L Antenna for 160m and 80m
- Inverted-V Dipole Antenna
- Inverted-V Dipole Height and Span Calculator
- Isotron-Style Loading Calculator
- J-Pole Antenna Dimension Calculator
- KD9SV Receive Loop — Pennant Loop for 160m & 80m
- Koch Fractal Dipole Calculator
- Lazy H Stacked Dipole Calculator
- Linked Dipole
- Log Periodic Dipole Array Antenna (Forward Design)
- Log Periodic Dipole Array Antenna (Reverse Design)
- Moxon Rectangle Antenna (Generic Band)
- Moxon Rectangle Dimension Calculator (Cebik Equations)
- NVIS Dipole Antenna
- Off-Center-Fed Dipole (OCFD) Antenna
- PAC-12 Style Portable HF Antenna
- Pennant Receive Loop Calculator
- Portable EFHW Antenna for SOTA & POTA
- Portable Linked Dipole Antenna
- Portable Magnetic Loop Antenna
- Quad Loop and Quad Beam Antenna
- Quarter-Wave Vertical and Radial Calculator
- Random Wire Length Checker
- Rhombic Antenna Calculator
- Screwdriver Antenna Coil Position Calculator
- Slinky/Spring-Loaded Vertical Calculator
- Sloping V Antenna Calculator
- SOTA Vertical Antenna for Portable HF
- Spiral Loop Calculator
- T2FD Antenna — Terminated Tilted Folded Dipole
- Tactical Whip Coil Calculator
- Tapped-Coil Base-Loaded Whip Calculator
- Trap Dipole Antenna
- Vee Beam Antenna Calculator
- Vertical Antenna Radial System
- W3DZZ 80m/40m Trap Dipole Calculator
- W3EWP Terminated Folded Dipole — Broadband HF Antenna
- W8JK Phased Array Calculator
- Window Screen Antenna Calculator
- Yagi Antenna Element Length Calculator
VHF / UHF / Satellite (39)
- 2-Element Yagi Antenna
- 2-Meter Copper Cactus Antenna
- 2-Meter Flower Pot Antenna
- 2-Meter Ground Plane Antenna
- 2-Meter J-Pole Antenna
- 2-Meter Slim Jim Antenna
- 2-Meter Yagi Antenna
- 23cm 1296 MHz Yagi Antenna
- 23cm Band Dish Feed Antenna (1296 MHz)
- 2m/70cm Collinear Antenna
- 3-Element Yagi Antenna
- 33cm Band Yagi Antenna (902–928 MHz)
- 5-Element Yagi Antenna
- 6 Meter Vertical Antenna
- 6m Band Dipole Antenna
- 6m Halo and 6m Moxon Antenna
- 6m Yagi Antenna
- 70cm Flower Pot Antenna
- 70cm J-Pole Antenna
- 70cm Slim Jim Antenna
- 70cm Yagi Antenna
- APRS Antenna
- Axial-Mode Helix Calculator
- Discone Antenna
- Dual-Band J-Pole Antenna
- Dual-Band Mag-Mount Whip Calculator
- Eggbeater Satellite Antenna Calculator
- Handheld Satellite Yagi Element Calculator
- HB9CV Phased Beam Calculator
- Hentenna Loop Calculator
- Ladder-Line Roll-Up J-Pole Calculator
- Lindenblad Circular-Polarization Calculator
- Portable Tape Measure Yagi Antenna
- Quagi (Quad + Yagi) Calculator
- Satellite Crossed Yagi Antenna
- Skeleton Slot Loop Calculator
- Turnstile Antenna Calculator
- Yagi Stacking Distance and Gain Calculator
- ZL Special Phased Beam Calculator
Antenna Components (20)
- 1:1 Current Balun / Choke
- 49:1 Unun for End-Fed Half-Wave Antennas
- 4:1 Current Balun
- 64:1 Unun — When to Choose It Over 49:1
- 6:1 Balun
- 9:1 Unun for Random Wire Antennas
- Coax-Wound Trap Construction
- Coil-and-Capacitor Trap Construction
- Hairpin (Beta) Match
- Homebrew SWR / Directional Wattmeter (Bruene Bridge)
- L-Network Antenna Tuner
- L-Network Matching
- Line Isolator (Shack-Entry Choke)
- Phasing Harness / Power Divider for Stacked Arrays
- Pi-Network Antenna Tuner
- Quarter-Wave Transformer and Stub Matching
- T-Network Antenna Tuner
- Toroid and Ferrite Core Selection Guide
- Variable Capacitor Selection for Magnetic Loops
- Z-Match / Link-Coupled Tuner
HF Antenna Calculators (105)
160m Inverted-L Antenna
Vertical run and horizontal top-wire length for a 160m Inverted-L given your available mast height.
20 Meter Magnetic Loop Antenna
Inductance and tuning capacitance for a 20m magnetic loop, cross-checked with two independent formulas.
4-Square Vertical Array
Element length and spacing for a 4-Square phased vertical array.
80 Meter Base-Loaded Vertical Antenna
Base-loading coil sizing for a shortened 80m vertical on a practical mast height.
80m–10m EFHW Antenna for Fixed Station Use
Dimensions for the 80m–10m efhw antenna for fixed station use.
All-Band Doublet Antenna
Recommended length cut for a half-wave at your lowest intended band, used multiband via ladder line and a tuner.
Antenna Gain dBd ↔ dBi Converter
Convert between dBd (referenced to dipole) and dBi (referenced to isotropic). Also converts to ERP and EIRP given transmitter power.
Antenna SWR Bandwidth and Q Calculator
Estimates SWR 2:1 bandwidth from element diameter and resonant frequency. Also converts between Q, bandwidth, and resonant frequency.
Antenna Trap LC Calculator
Calculates inductance and capacitance for a parallel LC trap resonant at a specified frequency, with coil winding details.
AX1-Style Short Whip Coil Calculator
Coil reactance and inductance for a very short (1.5–2 ft) whip. Flags when the whip is short enough that radiation efficiency will be notably reduced.
Base Loading Coil Calculator
Required inductance to resonate a short vertical or mobile whip, plus Wheeler formula coil winding specification.
Beverage Receive Antenna
Recommended total length for a Beverage receive antenna, based on your lowest intended frequency and desired directivity.
Bisquare Loop Calculator
Full-wave loop perimeter and each of the four equal sides for a diamond-shaped Bisquare loop strung between two supports.
Bobtail Curtain Calculator
Vertical element length, half-wave spacing between the three self-phased elements, and total top-wire span for a Bobtail Curtain.
Bruce Array Calculator
Bay length, jumper-drop length between bays, and total horizontal span for a folded zig-zag collinear Bruce array.
Buddipole-Style Coil-Loaded Arm Calculator
Given your telescoping arm's physical length, estimates the loading coil reactance and inductance needed on each side to reach resonance.
Buddistick-Style Vertical Coil Calculator
Same coil-loading approach as the Buddipole calculator above, applied to a single vertical whip fed against a counterpoise.
Bugstick Mobile Whip Coil Calculator
Budget manually-tapped mobile coil — same loading-coil approximation as the Hamstick and Screwdriver calculators, sized for a hand-set tap.
CFA Starting-Size Calculator
Reasonable E-field cylinder and H-field plate starting dimensions. This is a size estimate only — it does not endorse the design's disputed efficiency claims.
Classic Windom Leg Calculator
Total wire length and the ~36%-offset single-wire feedpoint tap for the historical Windom, fed with one wire into a link-coupled tuner (no balun).
Cobweb 5-Band Element Calculator
Folded-dipole element span for each Cobweb band — each band's zigzag element is independent, so trim only the one you're adjusting.
Cubical Quad Element Calculator
Full-wave loop dimensions for 1, 2, or 3-element quad antennas. Outputs side length, circumference, spreader arm length, and total wire required.
Double Bazooka Coax-Sleeve Calculator
Coax leg length (adjusted for your coax's own velocity factor) for a double bazooka, where the shield is the radiator and the center conductor is shorted at the far end.
EFHW Wire Length and UNUN Calculator
Half-wave wire length for any band, plus 49:1 UNUN winding specification for FT-140-43 or FT-240-43 toroid. Includes multi-band harmonic coverage.
EH Antenna Cylinder Size Calculator
Starting cylinder length and gap dimensions only — there is no closed-form formula for the matching network, which must be tuned empirically on the bench.
EWE Receive Loop Calculator
Post height, suggested post spacing, and starting termination resistor for a low-band EWE receive antenna. Optimize the resistor empirically against a known station.
Extended Double Zepp (EDZ) Calculator
Leg and total wire length for a center-fed 0.64-wavelength-per-leg Extended Double Zepp, fed with ladder line into a balanced tuner.
Fixed-Coil Mobile Whip Calculator
Single-band fixed-coil mobile whip — same math family as the screwdriver calculator, but for a fixed (non-adjustable) coil wound once per band.
Flag Receive Loop Calculator
Loop height, suggested loop width, and starting termination resistor for a rectangular Flag receive loop — a close cousin of the Pennant and EWE.
Flagpole Vertical Calculator
Quarter-wave element length and minimum recommended flagpole height for a vertical hidden inside a genuinely non-conductive (fiberglass) flagpole.
Folded Dipole Length Calculator
Overall half-wave length for a folded dipole — the fold raises feedpoint impedance to ~280–300 ohms without changing the resonant length.
Full Sloper Length Calculator
Standard half-wave dipole length for a sloper — electrically identical to a flat-top dipole, with directionality coming from the mounting angle, not a different length.
Full-Wave Delta Loop Calculator
Equilateral triangle loop dimensions — total wire, side length, apex height, base width, and phasing line for a two-element beam.
Go-Kit EFHW Length Calculator
Half-wave wire length and minimum counterpoise length for the HF leg of an emergency/go-kit antenna, fed with a 49:1 unun.
Gutter-Mounted Stealth Wire Calculator
Concealed wire length for a gutter-run stealth antenna — the gutter plays no electrical role and must not be used as the radiator itself.
Half-Wave Dipole Length Calculator
Calculates each arm length and total span for a horizontal or inverted-V half-wave dipole. Applies the standard end-effect velocity factor for wire or tube elements.
Hex Beam Antenna
Published G3TXQ Classic Hexbeam dimensions by band and portion (CW/SSB).
HF Magnetic Loop Antenna
Inductance and tuning capacitance for an HF magnetic loop, cross-checked with two independent formulas.
HF Receive Loop Antenna — Complete Construction Guide
Estimated loop inductance and reactance across common HF bands.
Inverted-L Antenna for 160m and 80m
Vertical run and horizontal top-wire length for a dual-band 160m/80m Inverted-L.
Inverted-V Dipole Antenna
Half-wave length with a slope-angle shortening correction for an Inverted-V.
Inverted-V Dipole Height and Span Calculator
Given apex height and desired arm angle, calculates horizontal span, tip height above ground, and effective arm length.
Isotron-Style Loading Calculator
Rough starting-point coil estimate for a capacitance-hat-plus-coil compact antenna. Actual designs require empirical tuning of plate spacing and coil taps together.
J-Pole Antenna Dimension Calculator
Radiating element length, matching stub length, and approximate feed tap position for any frequency. Works for 2m, 70cm, 1.25m, and HF J-poles.
KD9SV Receive Loop — Pennant Loop for 160m & 80m
Perimeter, area, and termination resistor for a KD9SV-style Pennant receive loop.
Koch Fractal Dipole Calculator
Straight-dipole reference length versus the folded Koch physical span, plus the extra wire needed per leg for the first-iteration zigzag fold.
Lazy H Stacked Dipole Calculator
Element length, collinear row span, and vertical stack spacing for a Lazy H — both rows fed in phase, unlike the W8JK's crossed feed.
Linked Dipole
Cumulative leg length per band for a multi-band linked dipole. Leave any band blank to skip it.
Log Periodic Dipole Array Antenna (Forward Design)
Given a frequency range, calculates approximate element count and boom length.
Log Periodic Dipole Array Antenna (Reverse Design)
Given a fixed element count, calculates the achievable frequency range.
Moxon Rectangle Antenna (Generic Band)
Dimensions for the moxon rectangle antenna (generic band).
Moxon Rectangle Dimension Calculator (Cebik Equations)
All five Cebik dimensions (A–E) for any frequency. Includes wire cut lengths, frame size, and installation notes. Works for any HF or VHF band.
Off-Center-Fed Dipole (OCFD) Antenna
Dimensions for the off-center-fed dipole (ocfd) antenna.
PAC-12 Style Portable HF Antenna
Base-loading coil sizing for a PAC-12-style portable vertical.
Pennant Receive Loop Calculator
Apex height, suggested base width, and starting termination resistor for a triangular Pennant receive loop.
Portable EFHW Antenna for SOTA & POTA
Dimensions for the portable efhw antenna for sota & pota.
Portable Linked Dipole Antenna
Same as the Linked Dipole calculator, sized for a lighter portable build. Leave any band blank to skip it.
Portable Magnetic Loop Antenna
Inductance and tuning capacitance for a compact portable magnetic loop.
Quarter-Wave Vertical and Radial Calculator
Vertical element length, radial lengths for angled or flat radials, and estimated feed point impedance for various radial configurations.
Random Wire Length Checker
Flags proposed wire lengths that land within 5% of a problematic half-wave multiple on common HF bands, and suggests known-good "sweet spot" lengths.
Rhombic Antenna Calculator
Leg length, approximate tilt angle, and typical gain for a terminated rhombic at your chosen leg length in wavelengths.
Screwdriver Antenna Coil Position Calculator
Estimates the required coil reactance and inductance for a given band — use as the starting motor position before fine-tuning electrically.
Slinky/Spring-Loaded Vertical Calculator
Loading estimate for a compression-spring-loaded vertical — use the result as a starting stretch length, then fine-tune by hand while watching SWR.
Sloping V Antenna Calculator
Leg length and suggested included angle for a Sloping V — a starting point before slanting both legs toward your target DX direction.
SOTA Vertical Antenna for Portable HF
Linked vertical element length per band, shortest (tip) band first. Leave any band blank to skip it.
Spiral Loop Calculator
Full wire length and approximate spiral diameter for a compact spiral-wound small transmitting loop at your chosen turn count.
T2FD Antenna — Terminated Tilted Folded Dipole
Dimensions for the t2fd antenna — terminated tilted folded dipole.
Tactical Whip Coil Calculator
Quick-deploy field whip loading estimate — same coil approach as the other mobile whip calculators, sized for rapid setup with a ground spike and counterpoise.
Tapped-Coil Base-Loaded Whip Calculator
Estimated tap position on a multi-band tapped base-loading coil — a starting point before sweeping SWR and adjusting the tap clip.
Vee Beam Antenna Calculator
Leg length, included apex angle, and typical bidirectional gain for a Vee beam, fed at the apex with ladder line into a balanced tuner.
Vertical Antenna Radial System
Quarter-wave radial length and an efficiency assessment based on your radial count.
W3DZZ 80m/40m Trap Dipole Calculator
Feedpoint-to-trap and trap-to-tip leg lengths for the classic 2-trap, 2-band W3DZZ, plus a suggested trap LC target.
W3EWP Terminated Folded Dipole — Broadband HF Antenna
Total wire length, termination resistor rating, and unun sizing for a terminated folded dipole.
W8JK Phased Array Calculator
Element length and crossed-phasing-line spacing for the classic 2-element close-spaced W8JK bidirectional array.
Window Screen Antenna Calculator
Each panel length and total frame span for an antenna built invisibly into an ordinary window screen frame. Panel width isn't critical to resonance.
Yagi Antenna Element Length Calculator
Generates a complete element length and spacing table for 2–11 element Yagis using DL6WU-based scaling, with boom correction for aluminium booms.
VHF / UHF / Satellite Antenna Calculators (39)
2-Meter Ground Plane Antenna
Vertical radiator and 4 drooped-radial lengths for a 2m ground plane.
23cm Band Dish Feed Antenna (1296 MHz)
Focal length and estimated gain for a prime-focus or offset-fed dish at 1296 MHz.
2m/70cm Collinear Antenna
Section length and phasing stub length (both coax-stub and hairpin methods) for a collinear.
33cm Band Yagi Antenna (902–928 MHz)
Element length and spacing table for a 33cm Yagi, with boom-type correction.
6m Band Dipole Antenna
Half-wave dipole length for 6m, in your choice of configuration and units.
Axial-Mode Helix Calculator
Circumference, diameter, turn spacing, axial length, and estimated Kraus-approximation gain for an axial-mode helix at your chosen turn count.
Discone Antenna
Disc diameter and cone length for a broadband discone antenna, referenced to your lowest coverage frequency.
Dual-Band J-Pole Antenna
Radiator and stub lengths for both bands of a dual-band J-Pole (2m + 70cm mounted side by side).
Dual-Band Mag-Mount Whip Calculator
Quarter-wave whip length for 2m, plus the 70cm third-harmonic frequency the same physical whip works on (with correspondingly higher SWR).
Eggbeater Satellite Antenna Calculator
Bent-element wire length, reflector screen diameter, and phasing-line length for a crossed-dipole Eggbeater with reflector screen.
Handheld Satellite Yagi Element Calculator
NBS thin-wire reflector/driven/director lengths for a tape-measure handheld satellite Yagi, tapered ~2% per additional director.
HB9CV Phased Beam Calculator
Reflector/director lengths and spacing for the compact HB9CV — same design family as the ZL Special, matched with a capacitor-tuned phasing harness.
Hentenna Loop Calculator
Vertical side length and top/bottom spacing for the folded-loop Hentenna. Feed tap position along the bottom wire is found empirically with an analyzer.
Ladder-Line Roll-Up J-Pole Calculator
Radiator and stub lengths for a twin-lead/ladder-line J-pole, using the same half-wave-plus-stub math as the copper-pipe J-pole with a ladder-line velocity factor.
Lindenblad Circular-Polarization Calculator
Dipole element length for a 4-dipole Lindenblad array — tilt each ~30° from horizontal, spaced 90° apart around the mast, fed in phase.
Portable Tape Measure Yagi Antenna
Element length and spacing table for a tape-measure portable Yagi.
Quagi (Quad + Yagi) Calculator
Reflector and driven quad-loop perimeters plus a tapered director-rod table for a Quagi, using the same ratios as this site's Quad and Yagi calculators.
Satellite Crossed Yagi Antenna
Element lengths (each of the 2 crossed elements) — does not compute the phasing harness for circular polarization.
Skeleton Slot Loop Calculator
Slot height and width for an Orr-style skeleton slot loop. Feed tap position along one long side is found empirically, the same as the Hentenna above.
Turnstile Antenna Calculator
Straight dipole element length and 90° phasing-line difference for a crossed-dipole turnstile fed in quadrature — no reflector needed.
Yagi Stacking Distance and Gain Calculator
Optimum vertical and horizontal stacking distance for two identical Yagis, combined gain estimate, and power splitter notes.
ZL Special Phased Beam Calculator
Rear/front element lengths, close-element spacing, and crossed phasing-line length for the classic close-spaced 2-element phased beam.
Antenna Component Calculators (20)
1:1 Current Balun / Choke
Turns needed on a toroid core for a 1:1 current choke at your target impedance and lowest operating frequency.
49:1 Unun for End-Fed Half-Wave Antennas
Primary and secondary turns for a 49:1 unun given your core and frequency.
4:1 Current Balun
Bifilar turns needed for a 4:1 current balun given your core, frequency, and coax-side impedance.
64:1 Unun — When to Choose It Over 49:1
Primary and secondary turns for a 64:1 unun given your core and frequency.
6:1 Balun
Trifilar turns per winding for a 6.25:1 balun given your core, frequency, and coax-side impedance.
9:1 Unun for Random Wire Antennas
Trifilar primary and secondary turns for a 9:1 unun given your core and frequency.
Coax-Wound Trap Construction
Coax length needed to wind a trap of the target inductance, using your coax's capacitance-per-foot rating.
Coil-and-Capacitor Trap Construction
Solve for the missing trap component — enter frequency plus either inductance (to find capacitance) or capacitance (to find inductance).
Hairpin (Beta) Match
Required hairpin shunt reactance and rod length given your measured feedpoint resistance and reactance.
Homebrew SWR / Directional Wattmeter (Bruene Bridge)
Calculate SWR and reflection coefficient from your forward and reflected power readings.
L-Network Antenna Tuner
Component values (both low-pass and high-pass configurations) for an L-network tuner matching your antenna to your line.
L-Network Matching
Series inductor and shunt capacitor values for an L-network matching your antenna feedpoint to your line impedance.
Line Isolator (Shack-Entry Choke)
Turns needed on a (possibly stacked) core for a shack-entry line isolator at your target impedance.
Phasing Harness / Power Divider for Stacked Arrays
Physical coax length needed for a specific phase delay between stacked/phased elements.
Pi-Network Antenna Tuner
Component values (both standard and alternate configurations) for a Pi-network tuner, given source/load impedance and desired virtual resistance.
Quarter-Wave Transformer and Stub Matching
Required transformer impedance and physical section length for a quarter-wave matching section.
T-Network Antenna Tuner
Component values (both standard and alternate configurations) for a T-network tuner, given source/load impedance and desired virtual resistance.
Toroid and Ferrite Core Selection Guide
Turns needed on a given core to reach a target inductance.
Variable Capacitor Selection for Magnetic Loops
Required tuning capacitance range across your target frequency span, given your loop's inductance.
Z-Match / Link-Coupled Tuner
Solve for the missing tank component — enter frequency plus either inductance or capacitance.