Michel Spelier Wins the World Again on 160 Metres
Michel Spelier Wins the World Again on 160 Metres
OP3T, operated by Michel Spelier ON7EH, finished first in Belgium, Europe and the world in the 2026 CQ 160 CW Single Operator Low Power category. The certificate records the result; the receive-chain work explains why serious topband stations never stop evolving.
A certificate can summarize a result. It cannot summarize the years of Beverage work, switching, current-path control, corrosion repairs, protection, attenuation and filtering that made weak signals usable for an entire contest.
The important lesson: Michel’s result is his achievement. No one box won the contest. The RF.Guru protector/isolator, Michel’s home-built high-pass filter and the rest of his receive system formed a chain whose behaviour he kept measuring until it stayed predictable under strong-signal conditions.
A Topband Station That Refused to Stand Still
Michel has spent years refining his 160-metre station. A good Beverage direction is only one part of that job. Outdoor switching must survive. Connections must remain stable. Common-mode paths must be controlled. Receiver protection must not become the new overload point. Attenuation and filtering have to match the actual spectrum at the site.
That attitude matters more on topband than any fashionable component. A multiplier near the noise can be lost through one overloaded stage, one noisy feedline route or one corroded field connection. Michel kept challenging every part of the chain instead of treating a previous result as proof that the system was finished.
The official CQ World Wide 160-Meter Contest results archive now lists the 2026 final CW scores, and Michel's certificate records the category result shown above. That ranking is evidence of operating and station performance together. It is not a controlled gain, SNR or product comparison.
The Receive Chain Used in the 2026 Contest
Michel confirmed that an RF.Guru RX Frontend Protector with galvanic isolation and RF limiting and his home-built high-pass filter were in line. The RF.Guru unit was already part of his testing before its public release, so his feedback reached us while the design and documentation were still being qualified.
The protector was one stage in a much larger system: receive antennas, field switching, feedlines, chokes, attenuation, filtering and the receiver itself. The product's current public function is bounded: it is a receive-path protection and isolation module, not a T/R switch and not a source of gain. Its detailed ratings belong on the maintained product page, not in a contest story.
The field collaboration is worth preserving because Michel did what good evaluators do. When the inserted chain behaved unexpectedly, he did not explain it away. He changed controlled variables, reported the result, and gave us a problem that could be reproduced and examined.
The Warning Sign Was an Unexpected Noise-Floor Change
On a quiet Beverage direction, inserting part of the receive chain appeared to raise the displayed baseline and make the trace less calm. That observation alone could not identify the cause. The display might have been showing added noise, intermodulation products, compression, gain-state changes or analyser behaviour.
The useful clue came from attenuation steps. In a linear chain, a small input attenuation change should produce a correspondingly predictable change at the observation point, provided the receiver state and measurement bandwidth remain fixed. Michel saw a much larger, nonlinear-looking response before preselection. That strongly indicated that one or more stages were being driven outside their small-signal region by energy that was not wanted on 160 metres.
This is the receiver problem formalized in ITU-R SM.332 on receiver selectivity: strong unwanted signals can create cross-modulation, intermodulation and degraded signal-plus-noise-and-distortion performance even when those signals are outside the wanted channel.
Michel’s High-Pass Filter Restored Predictable Behaviour
Michel placed his home-built high-pass filter ahead of the critical nonlinear part of the chain. Its job was not to make wanted 160-metre signals larger. It reduced strong LF/MF energy below the amateur band before that energy could consume headroom or mix into the passband.
With the high-pass filter in place, attenuation changes again tracked the displayed level much more closely. That is powerful diagnostic evidence: preselection removed the condition that had made the chain behave nonlinearly. It does not by itself identify every mixing pair or certify the filter's stopband across all source impedances, but it makes the overload mechanism far more plausible than “the limiter added noise.”
For a rigorous repeat, record the spectrum at the filter input and output with the same reference level, attenuation, preamplifier state, resolution bandwidth and detector. Then test the complete chain with two or more controlled strong signals while monitoring the wanted-frequency output. That separates filter rejection from receiver gain control and intermodulation.
Protection, Isolation and Filtering Have Different Jobs
| Stage | Job | What it does not prove |
|---|---|---|
| Limiter and transient protection | Reduce excessive peaks or coupled RF reaching a sensitive receiver input, within the module's declared limits | Better weak-signal SNR or immunity to every strong-signal combination |
| Galvanic isolation transformer | Break direct DC continuity between antenna-side and receiver-side conductors while transferring the wanted RF mode | Infinite common-mode isolation; stray capacitance, routing and accidental rebonding still matter |
| High-pass preselector | Reject strong energy below the wanted band before the stage that overloads | Protection from strong signals above the passband |
| Low-pass or band-pass preselector | Reject unwanted energy above the operating window, with loss and impedance stated | A benefit at a site where upper-HF energy was not the limiting mechanism |
A limiter is not an SNR amplifier. In normal small-signal operation it should stay in its linear region; during excessive input it trades amplitude fidelity for protection. Galvanic isolation can interrupt one conductive reference path, but parasitic capacitance and external cable current remain finite. A filter buys headroom only when it precedes the nonlinear stage and rejects energy that actually matters at that site.
Why a Little Filter Loss Can Still Win
Any passive filter adds insertion loss. On a quiet band, that loss can reduce SNR if the external noise after the filter approaches the receiver's internal noise. In a strong-signal environment, the trade can reverse: modest wanted-signal loss may be worthwhile when much greater unwanted energy is removed and the following stages return to linear operation.
The correct test keeps two questions separate:
- Does the filter reduce the unwanted spectrum and restore linear level tracking?
- Does the complete station copy the wanted signal with better SNR, readability or decoding under the same conditions?
Michel's attenuation experiment addressed the first question convincingly enough to guide the next step. Repeated A/B/B/A receive comparisons or simultaneous channels are needed for the second, because propagation and topband noise change while you watch.
The Next Experiment Is a Tighter Operating Window
After solving the below-band overload, the logical experiment is to test rejection above the 160-metre window as well. A suitable low-pass filter, or a band-pass response formed with both filters, could prevent upper-HF energy from consuming headroom in the limiter, switch, attenuator or receiver.
Could is the important word. Measure the spectrum first. Establish which stage overloads. Measure the candidate filter with the source and load impedances it will see. Compare with and without it, restore the baseline, and keep receiver state fixed. If upper-HF energy was not a limiting mechanism, extra filtering may add loss without improving copy.
What the Collaboration Changed
Michel tested pre-release RF.Guru hardware in a demanding station and reported an uncomfortable observation instead of a flattering one. We discussed the chain, reproduced the mechanism in the lab and used the result to sharpen the operating boundaries and documentation.
That is not a claim that the product caused the winning score. It is a better story: a world-class operator exposed a system interaction, a targeted filter restored linear behaviour, and field feedback improved the way the receive chain was understood and documented.
Congratulations, Michel
Congratulations to Michel Spelier, ON7EH, operating OP3T, on first place in Belgium, Europe and the world in the 2026 CQ 160 CW Single Operator Low Power category.
The certificate belongs to Michel. The engineering lesson belongs to every low-band station: protect the receiver, control unintended paths, preselect before the stage that overloads, and test the whole chain under the spectrum it actually sees.
Bottom line: topband receive performance is a chain property. Antennas, switching, feedlines, common-mode control, protection, attenuation, preselection and receiver linearity must all survive together. Measure the stage that fails; do not award the result to one box.
Primary records checked
Mini-FAQ
- Did the RF.Guru protector win the contest? No. Michel won through operating skill and a complete station. The protector/isolator was one documented stage in the receive chain.
- Does a limiter automatically improve SNR? No. It protects against excessive input within declared limits. Filtering and linear operation may improve practical copy when strong unwanted signals are the real problem.
- Why did the high-pass filter help? It reduced strong below-band energy before the overloaded stage, restoring more predictable level tracking in Michel's receive chain.
- Does galvanic isolation remove every common-mode path? No. It breaks direct conductive continuity, but transformer capacitance, cable routing and accidental rebonding still set finite RF isolation.
- Would a low-pass filter improve every 160-metre station? No. It helps only when above-band energy is consuming useful headroom; otherwise its insertion loss may be the larger effect.
- How do I confirm receiver overload? Use controlled attenuation and strong-signal tests with fixed receiver settings, then add preselection before the suspected nonlinear stage and restore the baseline.