TermiLoop 160–6 vs. 7-Band EFHW with Compensation Capacitor

TermiLoop 160–6 vs. 7-Band EFHW with Compensation Capacitor

Multiband HF antennas often promise “80–10 m” or “160–6 m” coverage, but not all designs achieve this efficiently. A common example is the 7-band End-Fed Half-Wave (EFHW) using a 49:1 transformer and a parallel compensation capacitor to flatten the SWR curve. While this makes the SWR look pretty on paper, the real RF efficiency is another story.

The Compensation Capacitor Problem

That “mystery capacitor” across the transformer primary is a parallel resonant circuit. It compensates for leakage inductance and stray capacitance, making the SWR curve flatter — but it does not improve transformer efficiency. In fact, it can:

• Mask high transformer losses at band edges
• Create narrow “blind spots” where efficiency collapses
• Increase heating in the ferrite at high power levels

The result is an antenna that may tune on 7 bands but wastes more power as heat in the transformer than it delivers to the far field, especially on 10 m and 12 m — and on 80 m with Type 52 ferrite.

How the TermiLoop Differs

The TermiLoop 160–6 takes a different approach. It is a terminated loop antenna — the termination is deliberate, providing broadband impedance stability from 1.8 MHz to 54 MHz. Yes, the termination resistor dissipates some RF power (by design), but the transformer is working well within its optimal range at all frequencies.

• Real multiband coverage — 160, 80, 40, 30, 20, 17, 15, 12, 10, and 6 meters with no retuning or traps
• Consistent efficiency — even where a 49:1 EFHW transformer struggles
• QRO ready — no “hot ferrite” failure risk on high duty cycle modes
• Predictable pattern — especially when installed as a sloper or inverted loop

But Doesn’t the Termination Waste Power?

Yes — a fraction of transmitter power is converted to heat in the termination resistor. However, this is a known and controlled loss, typically in the 15–30% range, and it stays consistent across bands. By contrast, a “wideband” EFHW with a compensation capacitor can be losing 40–50% of your RF on some bands without you even knowing, because the SWR meter is hiding it.

Band Coverage Reality

The TermiLoop’s design means it truly covers all HF bands plus 6 m. And on 6 m, the truth is: almost any HF antenna will work during Sporadic E. What matters is that the antenna presents a reasonable impedance to the radio and can handle the power — both of which the TermiLoop does easily.

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