Current thoughts are towards building an 8 section coax co-linear with a supposed 9DBi gain, taken from a tried and tested 70cm ham antenna design. (obviously re-calculated to 446mhz)
That's only 1.4% above 70cm, a 9dB antenna will have probably 2.5% bandwidth under 1.5:1, so you should be able to use it as-is.
446mhz handset (doing 500mW!)
If I ever come over to the UK, I'll bring my Motorola Spectra with me and the locals will hear me for sure - 120 watts, 250 channels, programmable from 450 to 490 Mhz
It would only take a few minutes to re-tune it up a few megs from it's current home on the 70cm Oz ham band (420-450Mhz).
Cheers from a cold, wintry Cornwall!
2 weeks ago, Sydney broke its all time temperature record - 46.6 degrees (Celsius). The airconditioner outdoor unit burned out, then the utility electricity went down, so we called it a day, went home by lunchtime, and cooled off down at the beach