Do the free to air Thai TV broadcast in HD and if I get a GMMZ HD box will I be able to get them without a subscription package?

Not much channel has HD. TV8 has it, but it is mainly marketing on TV (DirecTV).

If you have big satellite dish, you can get PSI HD for 1990 baht. GMMZ uses small Ku band 90 cm (or smaller) antenna and costs 2990 baht.

Free HD channels don't require subscription.

GMMZ has its channels on both KU and C-Band and the same receivers will tune either system. The HD receiver normally costs less than 2,000 baht (that 2,990 price is full price with a pay package for one year in addition to normal free channels and can be had for as low as 2,350 baht which is what I paid last month from Lazada).

And HD is not the broadcast standard for Thai TV - it is still the old PAL Colour (625) which is actually almost as good as much of the HD programming available (720) but is still 4-3 format but perhaps that will change with the digital broadcast roll out?

GMMZ has its channels on both KU and C-Band and the same receivers will tune either system. The HD receiver normally costs less than 2,000 baht (that 2,990 price is full price with a pay package for one year in addition to normal free channels and can be had for as low as 2,350 baht which is what I paid last month from Lazada).

And HD is not the broadcast standard for Thai TV - it is still the old PAL Colour (625) which is actually almost as good as much of the HD programming available (720) but is still 4-3 format but perhaps that will change with the digital broadcast roll out?

I got 1080i HD in HD channels in PSI HD.

I noticed 4:3 a few times due to incompetence of video editor in that channel. But most of the times it works fine.

Of course, it will take some time until TV 3/5/7 starts HD with real HD content, but majority of Thai homes still have CRT TV so they don't care.

1080i transmitted but the original content could be SD NTSC (never twice the same color) and for US content do not believe will be more than 720.

But you are correct PSI currently offers the most free HD channels from what I noticed when checking which system to buy. But GMMZ offers the pay channels if wanted. But for me PAL is so much better than the normal US video as to make HD something that is only needed when we get used to viewing much closer/larger screens as my eyes can not see much difference on a normal monitor at a normal viewing distance. For those with home theater type systems am sure it is great but for wife/family to watch different TV (5 sets) not needed (I mostly just view different shows on computer in same room at same time)

Thanks for your help. Does PSI need that huge ugly dish or is there something smaller available?

Believe PSI is only C-Band so would require the 1.5 meter dish (not really that big or ugly anymore when this close to equator). Remember rain fade is an issue for the Ku band systems and there are also more channels available with C-band. If you have the room do not believe most Thai will consider it ugly. Even starting to see on front of shop-houses here in Bangkok.