Building Delta T antennas is a very expensive thing. It needs funding from a small group. Individuals cannot afford huge expenses.
Look at the john titor coil machine, it is very small. Don't worry i have new idea.
Time flipper to not mention it, speack about presence of so called tachyon in germanium :
Such low sensibility transistor can bypass specific low voltage wave present in the natural etheric environnement. This waves resonnate at 350 Mhz. But even with 2n2222 the max is 300 mhz so forget or i will try with harmonic 55 mhz
0,2 volt sensibility germanium vs 0,7 volts silicon transistor vs 1,2 v mosfetts sensibility vs 0v but low rank bandwith magnetic amplifier.
I suggest to use mosfett with magnetic amplifier of minimum 30 turns ( just for mosfett remplacemebt, the others coil must be more than 30 turns, about 400 or more). Or use just magnetic ferrite amplifier without any mosfetts.

I have construct several parts either. Seems complexe but in fact, it is just 2 oscilator 90 dephased in astable config with 2 mosfett amplifier. One knob control the 2 oscilator 90 dephased at the same time gracefull of two 1n4007 diode. I have found that myself

, so please do not use it in a commercial project