I have a TS-450S (no tuner) and and SGC SG-237 Smartuner. The SGC needs
only 8 feet of antenna down to 3.5MHz. I used this setup in my camper,
and it did OK. If you're interested, both are currently up for auction
on eBay. Sold the camper, and not interested in mobile operation.

Rick
WØYGH