Nand gate u2a is the modulator and provides a 100 square wave modulated signal.
Ceramic resonator bfo circuit.
Perhaps they ll inspire me to build one hhny2all.
Discussion in general electronics discussion started by richard9025 feb 5.
Just curious for input at this point i m not an egineer so i can t directly contribute to our community with such a pico sized hack.
I will try to get some photographs off to hans in the next day or so but life has been hectic over this weekend.
In conclusion has anyone any photos of a mini sized bfo circuit built with a ceramic resonator.
3 used transistor bc548 9 volt supply voltage rf signal is produced with 455 khz ceramic crystal.
I taped a short length of wire from the output across the back of the circuit board and then adjusted the slug to give me the correct note.
Inverters u1d e along with ceramic resonator x1 form a stable 0 5 455 khz oscillator.
The input and output of the ceramic filter are tied together.
More about making coils.
Turn the receiver off and then on at any time and temperature the bfo frequency is exactly the same.
A ceramic resonator will not allow you to move the frequency more than a little.
Nand gate u2b buffers the original unmodulated signal and its propagation delay ensures that its output is in phase with the output of u2a.
The following circuit uses a 455 khz ceramic resonator which gives good frequency.
It s not perfect but definitely helps tune the if coils in the elenco am kit.
Oscillation is near 455 khz stable within a few hz.
Ceramic resonators ceralock lead type two terminal csbla series.
This i found easier that trying to set it up with the frequency meter.
Crystal oscillator vs resonator.
I built this because at the time i didn t have a signal generator that would perform am modulation.
455 khz tunable bfo circuit reply to thread.
The circuit is extremely stable.
Hi thanks for the comment.
The last time i checked i didn t find it on the site but.
The objectives of if alignment are to ensure that all tuned circuits in the if stages are tuned to the same frequency and that this frequency is the correct frequency usually 455khz.
This circuit was used to stop all the bfo drift.
I want to make a 455khz tunable bfo without any transformers based on the model on this page.
