Polar Plot vs Picnic Table

Why 4 Even Radials Beat the PERformer’s 90° Two-Radial Trick (in real POTA use)

The PERformer document by KJ6ER sells a simple idea: a quarter-wave portable vertical with the feedpoint about 4–5 ft up and two elevated tuned radials 90° apart. The punchline is a modeled “directional” vertical with “modest gain” and “3–4 dB front-to-back,” plus the suggestion that you can aim the radials toward the continent for “extra gain.”

This article is not about whether the PERformer works (it does). It’s about whether its polar-plot promise survives the reality of a park... and why a more balanced 3- or 4-radial layout will usually be at least as good, often better, and certainly more repeatable.

What the PERformer claims... and why it matters

The story hinges on one idea: two elevated radials at 90° are treated as “optimal,” producing a useful pattern bias you can aim. The document also correctly warns that common-mode current can ruin consistency and recommends a feedpoint choke.

The question for POTA is simple: does that “aimable” advantage show up reliably in the wild, where your antenna is surrounded by random conductors, uneven ground, shelter posts, wet leaves, a picnic table, and whatever your feedline happens to do today?

Two radials at 90° is not “a ground plane”... it’s intentional imbalance

A vertical with 3 or 4 radials evenly spaced is trying to approximate a symmetrical counterpoise. Symmetry matters because it forces the return currents to divide more evenly, which reduces the antenna’s urge to recruit other conductors (coax shield, tripod hardware, your body) as part of the radiating system.

The PERformer chooses a geometry that is not rotationally symmetric on purpose, because the author wants a pattern skew. That trade is real:

• More symmetry... less feedline drama, more repeatability.
• Less symmetry... more pattern skew in a clean model, but also more sensitivity to everything that isn’t in the model.

This is exactly the kind of “few elevated radials” system Rudy Severns (N6LF) warns about: performance becomes sensitive to modest asymmetries, nearby conductors, and even soil variations under the fan... which can shift resonance, feedpoint impedance, pattern shape, and efficiency in very noticeable ways. (See: QEX Mar/Apr 2012, N6LF.)

Common-mode is the elephant under the picnic shelter

The PERformer document is right to bring up common-mode. But a portable, coax-fed vertical is basically a common-mode generator unless you control it. ARRL puts it plainly: when shield and center currents aren’t balanced, the resulting common-mode current can radiate... meaning the coax “effectively becomes an antenna,” changing pattern, detuning, and SWR. (See: ARRL QST (Mar 2024) Common-Mode Current and Chokes.)

The uncomfortable part is what comes next: a single choke is not an off-switch. Chokes are frequency-dependent, placement-dependent, and common-mode on the outside of the coax forms standing waves... so one choke can help a lot in one setup and less in another.

GM3SEK’s practical guidance is exactly what portable operators run into: start with a choke at the driven element, and if one choke isn’t enough, add another useful location at the shack/rig entry. The sane way to stop guessing is measuring common-mode with a clamp-on current meter. (See: GM3SEK “Cost-effective ferrite chokes and baluns”.)

This is the core “NECtasy” trap: unless the model includes feedline routing, real choke impedance, coupling to nearby objects, and the rest of the mess, the plot is basically saying: “Here’s the antenna you wish you deployed.”

Why the real-world bias is usually small

In practical POTA terms, what matters is repeatable pattern bias you can actually exploit, not a single clean lobe from a single scenario. With a low portable vertical and a small elevated radial fan, your “error budget” is often bigger than the claimed advantage:

• uneven ground or slope
• wet vs dry soil under one radial
• metal table legs, fence wire, shelter posts, guy anchors
• feedline routing that becomes the “third radial”
• operator proximity and body coupling
• residual common-mode from incomplete isolation

Once you accept that, a modeled few-dB front-to-back becomes something you might see sometimes, but rarely as a reliable, repeatable tool. In typical activations, the practical bias you can count on is often in the “maybe a little” range... on the order of about 1–2 dB RDF when things line up, and sometimes effectively zero when they don’t.

Why evenly spaced radials win in repeatability

If your goal is reliable performance in uncontrolled environments, balanced radials are the grown-up choice. They don’t look as exciting in a screenshot, but they reduce the ways your system can accidentally turn into “vertical + coax + table + operator.”

What balanced radials buy you

• Less dependence on the feedline as the missing return path... so less pattern distortion and less on-site weirdness.
• More stable tuning and SWR because current division is less fragile when the geometry is symmetric.
• More reliable realized performance because fewer unmodeled losses and distortions sneak in under the radar.

“Gain” in the field is directivity multiplied by efficiency. A skewed plot is not a win if it’s paid for by feedline radiation, extra loss, or unstable current paths that don’t reproduce from activation to activation.

The comparison in one sentence

Two radials at 90° can produce a bit of pattern skew in an idealized setup, but it’s highly sensitive to real-world imbalance and feedline behavior... while three or four evenly spaced radials are boring in the best way: more symmetrical, less common-mode trouble, more repeatable ERP, and therefore at least as good... often better... once you include the losses and distortions that the polar plot didn’t pay for.

Practical POTA takeaway

• If you want a vertical that behaves similarly on every activation, use 3 or 4 radials evenly spaced, same length, same height, kept reasonably symmetric.
• Use a choke... but don’t pretend one choke is a universal cure. Be ready to add another choke location if needed.
• Treat “few-dB front-to-back” claims from a single NEC plot as indicative, not a field guarantee... especially when the deployment environment is chaotic.
• If you truly want directionality you can aim and trust, build a directional antenna (a real two-element vertical array, a small wire beam, etc.).

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Questions or experiences to share? Feel free to contact RF.Guru about portable antenna setups and common-mode fixes.