Lindenblad Antenna
The Lindenblad arranges four half-wave dipoles radially around a central mast, each tilted down at an angle from horizontal, and feeds all four in phase with equal power — no crossed elements, no quadrature phasing network. The tilt geometry itself is what produces near-circular polarization and a pattern that stays strong at low elevation angles all the way around the compass, which made it a natural fit for early satellite ground stations working passes low on the horizon and is why it's still built for that purpose today.
Four tilted dipoles, fed in phase
Unlike a turnstile or Eggbeater, which cross two dipoles and feed them 90 degrees out of phase to get circular polarization, the Lindenblad uses four ordinary linear dipoles arranged 90 degrees apart around a mast, each tilted downward from horizontal, and feeds all four with equal power and the same phase. Viewed from an angle off to the side (rather than straight down the mast), each tilted linear dipole's radiation appears elliptically polarized due to the viewing geometry — combine four of them around the compass and the composite pattern is close to circularly polarized across a wide range of azimuth and low elevation angles.
All four fed in phase, equal power -- no crossed elements, no quadrature network
Why this favors low elevation angles specifically
The Eggbeater bends and reflects its elements to concentrate energy toward zenith; the plain Turnstile favors the horizon with a level, symmetric pattern. The Lindenblad's tilted geometry sits between those two extremes by design, giving strong, fairly uniform gain across low-to-moderate elevation angles all the way around the compass — exactly the region where a satellite spends the start and end of a pass, and where a simple turnstile's polarization performance degrades most.
- Turnstile: straight elements, favors the horizon.
- Eggbeater: bent elements plus reflector, favors zenith.
- Lindenblad: tilted elements, favors low-to-moderate elevation angles around the whole compass.
An equal-power, in-phase feed network
Because all four dipoles are fed in phase rather than in quadrature, the feed network here is a straightforward equal-power four-way splitter with matched, equal-length feedlines to each dipole — mechanically simpler than the crossed-element quadrature networks a turnstile or Eggbeater needs, even though the antenna has twice as many elements.
Where the design comes from
Ernst Lindenblad developed this antenna at RCA in the same general era and engineering tradition as George Brown's turnstile, originally for broadcast and general-purpose omnidirectional coverage; amateur satellite operators later adopted it specifically for its low-elevation performance advantage on FM satellite passes.
Installation options
- Fixed mast, no rotator: the standard install — a simple fixed mount covers a wide azimuth and elevation range without tracking hardware.
- Rooftop or tower-top mount: keeping the array clear of nearby obstructions matters more here than for a tracked beam, the same consideration as the Eggbeater.
- Paired with a tracked beam: some stations run a Lindenblad for easy low-elevation passes and a tracked Yagi for higher-gain work on specific passes.
| Parameter | 2m (146 MHz) | Notes |
|---|---|---|
| Each dipole element | ~38.9 in (0.99 m) | Standard half-wave length, no bending |
| Tilt angle from horizontal | ~30° | Commonly cited starting point; adjust modestly for your priority elevation range |
| Azimuth spacing between dipoles | 90° | Four dipoles arranged evenly around the mast |
| Feed network | Equal-power 4-way splitter, equal-length lines | All four dipoles fed in phase |
Lindenblad Antenna Dimension Calculator
Materials for Lindenblad Antenna
Building the Lindenblad Antenna
Four identical dipoles mounted at a consistent tilt angle, fed through a simple in-phase splitter — no crossed-element phasing network to build here.
Cut all four dipole elements
Use the calculator above to get the standard half-wave length for your design frequency, and cut four identical dipole elements.
Build the central hub with four tilt brackets
Build or mount a central hub with four mounting brackets spaced 90 degrees apart in azimuth, each set to hold a dipole at the target tilt angle.
Mount all four dipoles at the tilt angle
Attach each dipole to its bracket, keeping the tilt angle and azimuth spacing consistent across all four.
Build the equal-power feed network
Connect the 4-way splitter at the hub, with four equal-length coax jumpers running to each dipole's feedpoint.
Connect the main feedline and mount to a fixed mast
Connect your main coax feedline to the splitter's input and mount the assembled array to a fixed mast — no rotator or tracking needed.
Sweep SWR and check coverage
Sweep the feedpoint for a clean resonant dip, then verify real-world coverage across low-elevation passes on the air.
| Symptom | Most likely cause | Diagnosis | Fix |
|---|---|---|---|
| Coverage is uneven around the compass | Tilt angle or azimuth spacing isn't consistent across all four dipoles | Check each dipole's tilt angle and azimuth position against the other three | Correct alignment so all four match the same tilt and 90-degree spacing |
| Circular polarization seems weak or inconsistent | Coax jumpers from the splitter to each dipole are unequal length | Measure all four jumpers against each other | Re-cut jumpers to equal length; phase errors between elements degrade the composite polarization |
| Low-elevation passes are weaker than expected | Tilt angle set too shallow or too steep for the priority elevation range | Compare actual tilt angle against the ~30-degree starting point | Adjust tilt angle modestly and re-test against real passes |
How is this different from the Eggbeater or Turnstile already on this site?
Both the Eggbeater and Turnstile use two crossed dipoles fed 90 degrees out of phase. The Lindenblad uses four separate, untilted-in-shape (straight) dipoles tilted physically and fed all in phase — a different mechanism for reaching circular polarization, optimized for low-elevation coverage rather than zenith or horizon specifically.
Do I need a rotator?
No — like the Eggbeater and Turnstile, this is a fixed-mount design covering a wide range of azimuth and elevation without tracking hardware.
Why four dipoles instead of two crossed ones?
The four-tilted-element geometry is what produces circular polarization here, instead of a quadrature feed network on crossed elements — it's a genuinely different mechanism, not just a cosmetic difference in element count.
What tilt angle should I use?
Around 30 degrees from horizontal is a commonly cited starting point; shallower or steeper tilts shift the pattern's balance between low-elevation and higher-elevation coverage.
Is the feed network really simpler than a turnstile's?
In one sense yes — it's an equal-power, in-phase split rather than a quadrature network — though you're building and phase-matching four feedlines instead of two, which is its own extra step.
Who developed this design?
Ernst Lindenblad developed it at RCA, in the same general era and tradition as George Brown's turnstile antenna.