Carbon Fixed Size Whips for the 10M/20M band vs Stainless Slider Whip

An evidence-based comparison using real-world measurements: why carbon looks “wideband,” what that actually means for TX efficiency, and why RX barely notices.

Weight vs Loss — Carbon Fixed Length Whips vs 5.2 m – 10.35 m (17–34 ft) Stainless Slider

TL;DR: Carbon whips are extremely light but essentially fixed-band tools: an ~89 in (~2.26 m) rod lands near 10 m, and a ~201.6 in (~5.12 m) rod lands within 20 m (no series element required in our 20 m tests). A 34 ft (10.35 m) stainless telescopic whip is heavier, but covers 10–40 m by simply sliding to resonance — no tuner, no traps, no loading. It also becomes an inverted-L for 80/160 m with a small base L-match, transmatch or loading coil and a wire attached to the top. Smaller stainless slider whips like 17 ft (5.2 m, 20 m band) or 25 ft (7.62 m, 30 m band) can also be used as inverted-Ls, but they are less efficient than the 34 ft (10.35 m) version.

Core ideas

• Carbon vs metal losses: Carbon radiators are lossier, but on 10/20 m near quarter-wave length the penalty is modest.
• RVS slider = tuner-free agility: A 34 ft stainless whip covers 10–40 m with no traps, no loading, no transmatch — just slide to resonance.
• Carbon = fixed lengths: Off 10/20 m, carbon rods need a base tuner.
• 80/160 m: The 34 ft RVS converts easily into an inverted-L via a top wire and a small base L-network or transmatch.

Band coverage cheat-sheet

Weight planning by scenario

Matching specifics (quick)

• Carbon 10 m: base series capacitor cancels +jX.
• Carbon 20 m: no series element needed.
• Carbon other bands: requires a base transmatch.
• RVS 34 ft 10–40 m: Slide to resonance — no tuner needed.
• RVS 80/160 m inverted-L: add top wire + small base L-match.

Scenario guidance

• Single band: Carbon + fixed match → ultra-light.
• Two bands: Two carbon whips, or RVS slider for no-tuner operation.
• 80/160 m: RVS inverted-L is drastically easier and far more efficient than carbon.

Takeaway

If you care about grams, go carbon. If you want tuner-free 10–40 m agility (and simple 80/160 m capability), a 34 ft stainless slider is the most versatile field whip available.

Measured Performance of Carbon vs Stainless Resonators

Carbon resonator

Same physical length as RVS

• 33.6 MHz, SWR 1.50, RL 14 dB
• Z ≈ 45.6 + j19 Ω (|Z| ≈ 49.4 Ω)
• L ≈ 90 nH
• Series C to cancel +jX ≈ 249 pF

Stainless (RVS) resonator

• 32.2 MHz, SWR 1.29, RL 18 dB
• Z ≈ 45.6 + j11.2 Ω (|Z| ≈ 46.9 Ω)
• L ≈ 55 nH
• Series C to cancel +jX ≈ 440 pF

After cancelling the small inductive component, the remaining resistive term is ~45.6 Ω — an excellent match to 50 Ω. This does NOT mean both antennas are equally efficient. It only means the feedpoint impedance looks similar.

20 m Version — Real-World Measurements

With both elements at the same physical length (RVS slider set to match the carbon rod), we measured the following around the 20 m band.

What this tells us

• Both behave like healthy near-¼-wave monopoles: resistive parts ~39–42 Ω with a small capacitive term (a hair “short” at 14.2 MHz).
• If you want X→0 exactly at 14.2 MHz, a tiny series L would do it (carbon ≈ 0.136 µH, RVS ≈ 0.175 µH) — but it’s unnecessary given the already low SWR.
• Carbon’s SWR bandwidth is slightly wider than RVS (lower Q due to higher loss), but on 20 m the effect is modest compared with 10 m.

Why the differences on 20 m are small

• Geometry dominates. Near ¼-wave, radiation resistance is ~36–40 Ω; a few ohms of extra loss barely moves SWR or resonance.
• Small resonance split. The ~200 kHz delta (~1.4%) between the dip frequencies reflects a tiny difference in effective electrical length — only ~7 cm on a ~5.1 m element.
• Bandwidth hides small changes. With FBW ≈ 2.5% for 1.5:1 SWR across the band, the implied loaded Q ≲ 47; carbon vs RVS Q shifts of a few percent are hard to see.

Why Carbon Looks “Wideband” on a VNA

Carbon-fiber and graphite composites have significantly higher RF resistance than metal. Higher RF resistance → more loss → lower Q. Lower Q → the SWR dip becomes wider.

This is a measurement artifact: a wide SWR dip is the hallmark of loss, not “built-in broadband magic.”

Carbon also shifts the resonance higher (33.6 vs 32.2 MHz) because loss changes current distribution and effective electrical length.

RX vs TX — Why Receive Barely Cares

At 1–35 MHz, man-made + atmospheric noise dominates the receiver noise floor. Antenna efficiency differences of 1–3 dB rarely change SNR. On transmit, however, every dB you lose in the radiator is a dB not radiated.

Matching the Two Whips

Carbon (fixed length)

• On 10 m → series C
• On 20 m → none required
• Other bands → a base transmatch

Stainless RVS (adjustable)

• Tune by sliding → no tuner required on 10–40 m
• For 40/80 → inverted-L with small base L-match

Efficiency Comparison

(Representative values for Ø 6 mm rods at 33.6 MHz; exact numbers depend on geometry and ground system.)

Near-quarter-wave whip (~2.2 m)

Radiation resistance ≈ 36.5 Ω. Ground loss ≈ 2 Ω.

Efficiency η = R_rad / (R_rad + R_cond + R_ground + R_tuner)

A Nuance Worth Discussing — Weight vs Loss

Carbon is lossier — but it is extremely light. For SOTA/POTA/QRP field operations, a carbon whip plus a small fixed series capacitor for one band can be dramatically lighter than carrying a stainless whip + tuner.

• No tuner needed on 10 m with a fixed series-C match; 20 m required no extra matching in our tests.
• Fixed C weighs under 2 g.
• Carbon whip weighs 40–65 g vs 180–230 g for stainless.

For fixed stations, stainless wins. For ultra-light portable work, carbon often wins.

Simple Lightweight Matching for 10 m (Carbon Whip)

The principle

Your carbon whip shows a small +jX on 10 m. A single series capacitor cancels that inductive reactance.

Carbon @ 33.6 MHz → X = +19 Ω → C ≈ 249 pF

Component recommendations

• Use C0G/NP0 or silver-mica capacitors.
• At least 100 V RF rating (more for QRO).
• Place directly at the base feedpoint.

Advantages

• No tuner → zero added loss.
• Only grams of parts.
• Stable match across the 10 m band.
• Perfect for ultralight SOTA/POTA.

A full 10 m carbon system (whip + fixed C + clamp) can weigh under 70 g total.

Carbon vs Stainless — At-a-Glance Comparison

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