Welcome!
I plan to built a CB band transceiver. I know that it's a lot of them available in attractive prices, bu it comes to getting more knowledge and experience in RF circuits.
I'll describe you my idea:
It must be simple AM/FM CB band transceiver, tuned with PLL syntheteiser, output power about 5W.
TDA2003 - AM modulating amplifier
BF256 - HF generator
BF195 - HF separator
TDA1220B - AM/FM IF II nd. stage and demodulator
TBA820M - audio amplifier
BF240 - Ist. stage driver
BD139 - IInd. stage driver
KT612 (Russian) - output transistor working in the 'C' class
SA612 - mixer/ additional RF generator
The frequency forming:
Example: transmitting/ receiving on 27,0MHz, IF of this radio is 10,7MHz
TX:
The main generator gives us 37,7MHz. It is connected to the mixer. The same time
the additional generator produces 10,7MHz. This mixer works as differential mixer s0 we have 37,7 - 10,7 =27,0 MHz. Than in comes to the RF amplifiers and finally tho 4 segment Π filter and aerial
RX: The Π filter plays role of band filter. Than we have RF amplifier (BF256) connected by tuned circuit with SA612. Of course the addtional generator is not working in RX mode. Then after choose of the demodulation the IF signal gets on TDA1220B and at the end to TBA820M.
Can you answer may question if it works, please.
With best regards
Jan
I plan to built a CB band transceiver. I know that it's a lot of them available in attractive prices, bu it comes to getting more knowledge and experience in RF circuits.
I'll describe you my idea:
It must be simple AM/FM CB band transceiver, tuned with PLL syntheteiser, output power about 5W.
TDA2003 - AM modulating amplifier
BF256 - HF generator
BF195 - HF separator
TDA1220B - AM/FM IF II nd. stage and demodulator
TBA820M - audio amplifier
BF240 - Ist. stage driver
BD139 - IInd. stage driver
KT612 (Russian) - output transistor working in the 'C' class
SA612 - mixer/ additional RF generator
The frequency forming:
Example: transmitting/ receiving on 27,0MHz, IF of this radio is 10,7MHz
TX:
The main generator gives us 37,7MHz. It is connected to the mixer. The same time
the additional generator produces 10,7MHz. This mixer works as differential mixer s0 we have 37,7 - 10,7 =27,0 MHz. Than in comes to the RF amplifiers and finally tho 4 segment Π filter and aerial
RX: The Π filter plays role of band filter. Than we have RF amplifier (BF256) connected by tuned circuit with SA612. Of course the addtional generator is not working in RX mode. Then after choose of the demodulation the IF signal gets on TDA1220B and at the end to TBA820M.
Can you answer may question if it works, please.
With best regards
Jan