Hi Pete, I have had the best range success using the Revolution 2.4GHz with the 3" antenna. I am amazed how well it works inside the tender of my die cast USA Hudson. Over 90’ range. I mount the receiver off the floor about 2-3 inches. Then point the antenna to the sky.
Also installed the AirWire in the USA Trains Hudson using the optional extended antenna mounted vertically inside plastic tubing. Then set the output power to full. The Revolution still has twice the range. The AirWire uses a 900 Mhz radio frequency. In my experience the three 2.4Ghz systems I offer get more range inside a metal shell.
With the Revolution you can mount all the gear inside. It is best for the antenna to point to the sky rather than laying parallel to the earth or the metal body. You can try the Revo RX inside the shell for a range test.
Don