Hi to all forum users.
I have problem with bulding a medium wave transmitter.
I have designed circuit and put it together on bread bord.I using Epson programmable oscillator (4,57 MHz) and johnson decade counter in order to divide signal by 10 (457 kHz).I have a complementary power amplifier as a output stage.I connecting output stage with antenna by transformer( I trying with 21 turns on ferrite rod).
My questions:
-I need approximately 0.1W output power and 50 m range , but I don't know how to measure it?
-Another problem is connected with proper antenna impedance matching. I couldn't find any formula for transformer to calculate how many turns of a wire are need to be made on a ferrite rod in order to get right impedance so I tried few random numbers of turns.Do somebody know how impedance matching should be ?
- I made simulation in LTspice but results are not the same like in reality. So, if somebody could tell me-Do I biased transistors in good manner ?
Circuit in attachment.
Best Regards
I have problem with bulding a medium wave transmitter.
I have designed circuit and put it together on bread bord.I using Epson programmable oscillator (4,57 MHz) and johnson decade counter in order to divide signal by 10 (457 kHz).I have a complementary power amplifier as a output stage.I connecting output stage with antenna by transformer( I trying with 21 turns on ferrite rod).
My questions:
-I need approximately 0.1W output power and 50 m range , but I don't know how to measure it?
-Another problem is connected with proper antenna impedance matching. I couldn't find any formula for transformer to calculate how many turns of a wire are need to be made on a ferrite rod in order to get right impedance so I tried few random numbers of turns.Do somebody know how impedance matching should be ?
- I made simulation in LTspice but results are not the same like in reality. So, if somebody could tell me-Do I biased transistors in good manner ?
Circuit in attachment.
Best Regards
Attachments
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