Currently show below as available free HD quality on GMMZ white box using C-band antenna (note Nat Geo wild is a pay station but no payment has been required for several years) - other HD stations require payment.

Channel Station

2/41/312 ONE

4.............GMM Channel

41...........ONE

306.........Channel 3

307.........Channel 5

308.........Channel 7

309.........MCOT

311.........TPBS

312.........ONE

313.........Thairath

314.........PPTV

438.........Nat Geo Wild

I have just checked the High Definition channels which are available on my GMM-Z White HD Box using Ku band dish without subscription.

GMM channel number Station

168 Nat Geo Wild HD

313 Thairath TV HD

438 Nat Geo Wild HD

Other stations carry the identifier "HD", but are not transmitted in HD by GMM-Z, eg 001 - 3HD & 306 - 3HD