EMCSQ

As an advanced approach I would chose ammonia borane for storing hydrogen, which releases it, if heat is applied.
Ammonia borane - Wikipedia, the free encyclopedia
'It is more hydrogen-dense than liquid hydrogen and also able to exist at normal temperatures and pressures'.
It can be used as an energy source for planes: (small prototype)

and as well for cars.
You might need a fuel cell stack , here are different choices for the use with methanol or hydrogen:
Tropical - Hydrogen FC Systems

42.8khz * 2^9 = 42800 * 512 = 21913600 = 21.9 MHz not GHz
Significant Radio Astronomy Frequencies

Puharich mentions this frequency although he produces it by using a 'highly nonlinear load' generating the harmonics.
Energy From H2O Resonance - YouTube
at >= 35:46

Quote from another forum:
Gas from Water, (WaterFuel), HHO technology - Page 9 - Boat Design Forums
Post:126
The lowest resonance of the water molecule is 22.235 GHz. This frequency is almost 10 times higher than the operating frequency of the microwave oven (2.45 GHz). The BREAKING rezonant frequency is so high it cannot be produced in your car, *****.

Meyer DID talk about that particular frequency in your patents.

Hello

according to the info provided by attachment a 22 GHz modulated Laser will enhance the production of hho, because it's the resonance frequency of water.
Also a pwm triggered with this frequency should work fine.
I am looking for ready made circuits which generate this frequency slightly variable and with an dc-offset as output signal.
I think one needs expert skills to build this device and to make measurements; therefor I will not attempt to build it myself.
Where can I buy such device?