Quick Q about radio signals in current climate

[Tarrel]

So correct me if I am wrong but is PMR 446 of 440 to 447 Mhz higher than CB radio at 28 to 30 Mhz ?
and is amplitude modulation better in shit weather than frequency modulation??

Yep, PMr446 is UHF, CB is HF. I don't know if there's a difference between AM and FM as far as weather is concerned, but AM is subject to more interference, as has been mentioned, especially electrical interference.

UHF and above can be affected by very local weather conditions, whereas HF DX (long distance) is more affected by ionospheric conditions.

Personally, for short range (<10km) tactical communication, I'd go VHF. For more regional coverage I'd use HF with an NVIS antenna. This avoids need for line-of-sight. NVIS (Near Vertical Incidence Skywave) basically shoots your signal straight up in the air. It bounces off the ionosphere and comes scattering back down. Imagine pointing a garden hose straight upin the air and think about the fallout pattern of the water. You can make an NVIS antenna easily by taking any horizontal antenna (say a dipole or long wire) and moving it closer to the ground (or your earthed surface). For example, if you have a long HF whip antenna on your car, bend it over in an arc and tie the end down with some (insulating) cord - bingo, an NVIS antenna. NVIS won't work with VHF or above - the energy of the signal is too high and it will punch through the ionosphere.

Sorry if this is teaching grandmother to suck eggs, or if this has been covered elsewhere.