brief demo of a pieced together low power AM TRANSMITTER circuit, with individual RF modules borrowed from several sources(noted below) - transmitting on a frequency of 1630 khz... with audio from a podcast providing the AM modulation - [ Ссылка ]

this circuit is first being evaluated for its transmit AUDIO FIDELITY to see how well the AM modulator stage performs

1ST STAGE:
Low noise crystal oscillator:
"CRYSTAL OSCILLATOR PROVIDES LOW NOISE"
[ Ссылка ]

2ND STAGE "grounded base" buffer:
from QRP CLASSICS by ARRL page 60 Fig 48

3RD STAGE - 3 transistor pre-amp module:
"Class A" RF amplifier module from QRP CLASSICS by ARRL
page 267 Fig. 4 (Broadband linear amplifier strip)

4TH STAGE:
RF AMP - (3rd transistor in the Broadband linear amplifier strip as noted in the 3RD STAGE notes) a bit of the design from QRP CLASSICS by ARRL page 60 Fig 48 (the 2n3866) & from QRP CLASSICS by ARRL page 267 Fig. 4(final class A, transistor RF amp)

5TH STAGE: the AM MODULATOR:
using the Q3 AM modulator transistor setup from:
[ Ссылка ]

NOTE: you have to dial this circuit down until you are compliant with part 15 if you wish to use this as an LPAM transmitter...so that the DC INPUT Power to the 2N3866 final RF amp does not exceed 100 mW.

NOTE: not shown is the 1. RF LOW PASS FILTER which must be added to the above stages and the 2. antenna matching LC network

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