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CHA MPAS Lite Band Change, Tuning, and Optimization

On higher bands, the MPAS Lite guide provides SS17 length starting points for no-tuner operation with a 25 ft counterpoise; on other bands and configurations, use a suitable tuner or coupler as required.

Product Installation Guides CHA MPAS Lite Reviewed 2026-07-14
In plain language: On higher bands, the MPAS Lite guide provides SS17 length starting points for no-tuner operation with a 25 ft counterpoise; on other bands and configurations, use a suitable tuner or coupler as required.

Optimization begins by preserving the documented counterpoise and changing only the whip length for the selected band.

Build the documented shape

  • For 30, 20, and 17 m, the guide starts with the SS17 fully extended.
  • For 15, 12, and 10 m, the guide starts near 12 ft with the top three sections down.
  • For 6 m, the guide starts near 5 ft with only the bottom three sections extended.
  • Verify the installed result rather than treating the table as a guaranteed match.

Why an operator chooses it

The table is a practical starting point from the official test configuration. Mount, ground, nearby metal, and feed-line routing can move the measured minimum.

Read the site before opening the bag

Mark repeatable section positions if the same station returns to them often, but recheck after a site or hardware change.

Common ways this goes wrong

  • Using the length table without the 25 ft counterpoise.
  • Changing whip length while the tuner is still applying an old solution.
  • Forcing thin upper sections.
  • Publishing the table as a no-tuner guarantee for every installation.

Before you transmit

  • Confirm the exact radiator, matching unit, return path, feed line, and support arrangement.
  • Keep conductors and supports clear of power lines and uncontrolled public access.
  • Reproduce the guide dimensions before experimenting.
  • Inspect every connection and begin testing at low power.
  • Record geometry, band, tuner state, and the result before changing one variable.
Boundary: The guide’s SWR values are typical for its setup. They are not an installed-system warranty.
Use the current source before deployment.

This lesson explains the decision. The official guide controls assembly, ratings, configuration details, and safety.

Open the MPAS Lite User Guide · Open the MPAS READY Product Guide · View the current product page

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