#6865
Guenther
Spectator

Hi,

all parts like double variable capacitor, ferrit antenna, oscillator coil, IF filter (colored red-yellow-white-black) are standard and can be taken from old and unused pocket radios – otherwise it will be noticed e.g. in my BOY’S RADIO coming up next because it uses nearly the same circuit but a “HF transformer”.

For the wiring I use since many decades the so-called Veroboard (wholes  with 2.54 or 5.08 mm distance all over the “PCB” with copper eyes for soldering), suitable sized and wired underneath:

This allows corrections and extensions without new design of the board. Critical circuits I use to test prior with the same material and with socket(s) for transistor(s) to select the best ones and to make additional experiments, here: using an output transformer for loudspeaker / second AF amplifier OR earphone usage only:

The ferrite antenna / capacitor-block is designed for multiple usage. The advantage: both components are adjusted for best reception once and can be used anywhere else. Because of the need of low impendance input in transistor radios the similar block for my tube superhets (reflex & “normal”, steel or pencil tubes) is quite vice versa, which means that the LC circuit has to be connected to grid 1 of the first tube, and the coupling part is for antenna input.

My circuits with the ZN414 (standard receiver and superhet applications) will come up, too… Be careful to use the ZN414 block because the IC only works with up to 1.5V (best: 1.3 V)!

Therefore I created a special block just to be sure that NEVER any problem will occur … and why not integrate all and ever required parts for usage in this block, too?!

I have a lot of stuff to introduce – please be patient 😉