0
\$\begingroup\$

I soldered one radio circuit for a wave transmission with ~107 MHz frequency and I got good results. I simulated this circuit in LTSpice, too. What I have seen was that the wave got AM modulated and the result of all was that the circuit feeding voltage was modulated properly according to the input, too. My question is about, if the feeding voltage is responsible for the carrier frequency and if it is the reason for reaching long distance during transmission?

circuit

result

\$\endgroup\$
5
  • 2
    \$\begingroup\$ It's hard to understand what you're asking here. \$\endgroup\$
    – Hearth
    Commented Oct 1, 2023 at 23:26
  • \$\begingroup\$ I do not care about impedance matching of antenna for now. What I want to know is, if the voltage that powers up the circuit, is a part of this carrier signal.. What I mean is, carrier signal is kind of signal with DC offset and inside the modulated wave... ? \$\endgroup\$
    – user321220
    Commented Oct 1, 2023 at 23:32
  • \$\begingroup\$ You have twi voltage sources which doyou consider "feeding"? \$\endgroup\$
    – user319836
    Commented Oct 1, 2023 at 23:57
  • \$\begingroup\$ did you forget to include some words in the title? ... it makes no sense \$\endgroup\$
    – jsotola
    Commented Oct 2, 2023 at 0:06
  • \$\begingroup\$ @lastime sorry, that comment of yours still makes no sense. My native language isn't English, it has always helped me to put things in mathematical formulas. So, I would recommend you 1. Describe the signal that your antenna transmits in a mathematical formula and 2. Then say which parameter of that formula has to do with the voltage you mean. \$\endgroup\$
    – Marcus Müller
    Commented Oct 2, 2023 at 0:29

2 Answers 2

Reset to default
0
\$\begingroup\$

It appears that you have wired an RF amplifier for 107 MHz, following a schematic that you've successfully tested on LTSpice.

You have successfully received at a distance, an unmodulated / amplitude modulated 107 MHz carrier fed to the RF amplifier with it's antenna connected.

The RF amplifier is responsible for amplifying the power of the carrier being fed to the antenna for transmission.

Higher the required range greater the required transmitted power and greater the DC power input to the RF amplifier.

\$\endgroup\$
0
\$\begingroup\$

My question is about, if the feeding voltage is responsible for the carrier frequency and if it is the reason for reaching long distance during transmission?

Obviously, you have built an oscillator with LC and RC oscillating frequencies adopted to each other. It seems to work like in the graphic you have presented. The input voltage is not responsible for the oscillating. You made simply a sine wave generator which is being oscillated with your drawn circuit. Of course, the higher voltage, the stronger the transmission. It depends on impedance match and the efficiency of antenna.

\$\endgroup\$

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.