Mechanical safety comes before SWR:
The CHA UCM turns a sound table edge, rail, or similar support into a portable 3/8-24 antenna position and SO-239 feed-through. It is a clamp mount—not a tuner, transformer, loading coil, mast, or universal compatibility approval.
Stop-work conditions
- Never use the temporary clamp on a moving vehicle.
- Add guying or secondary retention whenever the completed antenna requires it.
- Stop if the mount shifts, the surface deforms, or the antenna becomes unstable.
- Do not use near power lines, uncontrolled public paths, or a surface with unknown strength.
Control wind, leverage, and movement
- Use the isolated top 3/8-24 stud only with a documented radiator or feed unit.
- Attach ring-terminal counterpoise wires to the side screw when the antenna requires them.
- Banana-plug radial products need a separately documented banana interface; they do not plug directly into the UCM.
Recover without creating the next failure
- Inspect the aluminum body, top insulator, stud, SO-239, side screw, clamp faces, and handle.
- Clean and dry the support surface and mount.
- Substitute a known-good coax before blaming the mount for an RF fault.
- Record the complete antenna, surface, feed line, return path, frequency, and analyzer result when seeking support.
Guying can stabilize a documented installation, but it does not increase the published load or make an unapproved support chain safe.
Use the current CHA UCM instructions.
