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Chameleon Knowledge Base · The Complete Online HF Antenna Handbook

Why the CHA F-LOOP Must Be Retuned

The F-LOOP 3.0 must be retuned because its high-Q resonant circuit covers only a narrow slice of spectrum at one capacitor setting. Changing frequency changes the required capacitance.

Product Installation Guides CHA F-LOOP Series Reviewed 2026-07-14
What matters in the field: The F-LOOP 3.0 must be retuned because its high-Q resonant circuit covers only a narrow slice of spectrum at one capacitor setting. Changing frequency changes the required capacitance.

What the operator is controlling

Moving the loop, rotating it near conductors, changing radiator configuration, or altering coupling can also shift resonance and match. The guide therefore keeps the tuning control accessible to the operator.

Where people get into trouble

An external tuner at the radio can make the transmitter see a lower SWR while the loop itself remains off resonance, increasing loss or stress. The guide explicitly says not to use one for this purpose.

A repeatable field method

Set the band switch and configuration correctly, tune the loop itself at low power for receive peak and minimum SWR, then retune whenever frequency or installation changes.

Product boundary

These F-LOOP instructions preserve the documented discontinued CHA F-LOOP 3.0 system for existing owners. They do not transfer hardware, tuning, power, or compatibility claims to the separate pre-production CHA F-LOOP 4.0.

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