Hello Flea_Flyer. Building a radio set is not an easy task. Not only the electronics knowledge is required,about high-frequency and low-frequency, but also a minimum number of instruments during the work, such as a universal meter, griddipper and field strength meter.
A good universal meter does not have to be expensive, they are available in many types and qualities, but the requirements are not high.
A griddipper is actually necessary if you want to wind the coils yourself for the various circuits in the transmitter and receiver. A griddipper is an tuneable oscillator in a number of ranges. Each range can be selected by inserting the corresponding coil into the griddipper. A moving coil meter is included in the instrument which displays the amplitude of the internally generated oscillator signal. The frequency is visible on the scale/dial of the tuneable oscillator and each range is displayed separately on it. If a coil is coupled to the corresponding capacitor and the dipper coil is brought close to it, the indicator will fall back slightly when the frequency is turned over the resonance frequency, indicating a dip. My dipper I made about 50 years ago and still doing ver well, it also can be used as trnsmitter, FM an AM modulated, FM to have an indication of the superregen receivers bandwidth I build.
For a coil, the number of turns in combination with the correct core material are very important, the core material also must be suitable for the frequency. Then you can talk again about coils with several coils at a holder.
If you want to build a transmitter, a field strength meter is needed for tuning the various circuits.
Because I am familiar with tube valve technique I designed and made a 4 channel tone transmitter. Because of the availability I did use the Tube ECC 82 double triode (MOPA, oscillator amplifier), also because of the 12 V filament voltage, so I combined it with a 12,5 VDC supply voltage for the transistor 4 channel tone oscillator and converter 12,5 / 100 VDC Anode tension, 10 AA cells and converter in the battery. The tone oscillator is at the backside of the circuit board.
Reproducing this transmitter isn’t easy. I didn’t even make detailed plans for myself.