A simple box with vented lid to convert 10-40V to 7.4V for hanheld V/U radios. I made it as a supplement to https://www.thingiverse.com/thing:5326830.

The choosed DC-DC converter https://grobotronics.com/dc-dc-step-down-1.3-35v-3a.html seems noiseless on VHF and UHF bands and keeps the demanded by FT-4X load well enough.

Anet

A8

No

Yes

0.3

20

Use supports as needed (support distance 6mm its ok).
Mark clearly input and output connectors. If you give 12 volts to the wrong side radio will get 12V as well.

YAESU FT-4X battery eliminator: https://www.thingiverse.com/thing:5326830

Sketchup