Version 4.1 SHEET 1 1820 816 WIRE -176 80 -256 80 WIRE -16 80 -96 80 WIRE 16 80 -16 80 WIRE 16 128 16 80 WIRE 176 128 16 128 WIRE 304 128 240 128 WIRE 416 128 304 128 WIRE 448 128 416 128 WIRE 464 128 448 128 WIRE 16 144 16 128 WIRE 16 144 -32 144 WIRE 80 144 16 144 WIRE -32 176 -32 144 WIRE 80 176 80 144 WIRE 304 176 304 128 WIRE 416 176 416 128 WIRE -32 320 -32 256 WIRE 80 320 80 240 WIRE 80 320 -32 320 WIRE 192 320 80 320 WIRE 304 320 304 240 WIRE 304 320 192 320 WIRE 416 320 416 256 WIRE 416 320 304 320 WIRE 192 352 192 320 WIRE -256 400 -256 80 WIRE -128 400 -256 400 WIRE 304 400 -128 400 WIRE -432 464 -464 464 WIRE -128 496 -144 496 WIRE -464 528 -464 464 WIRE 112 528 112 512 WIRE 304 528 304 400 WIRE 304 528 112 528 WIRE -144 560 -144 496 WIRE 112 576 112 528 WIRE -464 672 -464 608 WIRE -144 688 -144 640 WIRE 112 688 112 656 FLAG 192 352 0 FLAG -128 400 incoming_signals FLAG -432 464 Local_osc FLAG -464 672 0 FLAG -144 688 0 FLAG -128 496 1khz_audio FLAG 112 688 0 FLAG -16 80 bandpass FLAG 448 128 out SYMBOL cap 64 176 R0 SYMATTR InstName C1 SYMATTR Value 250p SYMBOL ind -48 160 R0 SYMATTR InstName L1 SYMATTR Value 40µ SYMBOL diode 176 112 M90 WINDOW 0 0 32 VBottom 2 WINDOW 3 32 32 VTop 2 SYMATTR InstName D1 SYMATTR Value crystalDiode SYMBOL cap 288 176 R0 SYMATTR InstName C2 SYMATTR Value 10n SYMBOL res 400 160 R0 SYMATTR InstName R1 SYMATTR Value 1k SYMBOL bv 112 560 R0 WINDOW 3 -84 103 Left 2 SYMATTR Value V=2*V(Local_osc)*(1+0.5*V(1khz_audio)) SYMATTR InstName B1 SYMBOL voltage -464 512 R0 WINDOW 123 0 0 Left 2 WINDOW 39 0 0 Left 2 WINDOW 3 -46 106 Left 2 SYMATTR Value SINE(0 100m 1.6Meg) SYMATTR InstName V2 SYMBOL voltage -144 544 R0 WINDOW 123 0 0 Left 2 WINDOW 39 0 0 Left 2 WINDOW 3 -38 101 Left 2 SYMATTR Value SINE(0 1 1k) SYMATTR InstName V3 SYMBOL res -80 64 R90 WINDOW 0 0 56 VBottom 2 WINDOW 3 32 56 VTop 2 SYMATTR InstName R2 SYMATTR Value 50R TEXT -64 -304 Left 5 ;Crystal set TEXT 632 544 Left 2 ;choosing a freq somewhere in the MW band.\nfor ease of design letting 2pie f = 10 Meg.\nnote that 2 pie f is called angular velocity\nI am representing this as w (small greek letter Omega)\nso f = 1E7/ 6,28 = 1.6 Mhz\nwith C at about 250 pF, \n1/ (wc) = 1 / ( 10 Meg x 0.25 nF) = 1000/ ( 10 x 0.25 ) \n= 1000/ 2.5 = 400\nas wL will also be 400 at w= 1E7 \nL = 400/ 10 Meg = 40 uH TEXT 96 72 Left 2 ;diode is eg germanium TEXT -496 800 Left 2 !.model crystalDiode D(Ron=50 Roff=1Meg Vfwd=.15) TEXT -480 720 Left 2 !.tran 0 0.1 0 100n TEXT -288 432 Left 2 ;AM modulated 1.3 Mhz Source TEXT 616 112 Left 2 ;note that the diode is not a normal modern diode.\nthe simple diode characteristic that I have created here has a much lower \nforward voltage drop (150mV)\nand a high on resistance a bit like a crystal-wisker diode, or a germanium diode.\neven with such a diode you need a minimum of about 200mV from the aerial to\nget any output at all.\n \nThe only voltage present is what comes from the Aerial so, if I put the \n600mV or so forward voltage drop of a normal silicon diode in the circuit, \nit would only work with very strong signals. TEXT 752 24 Left 4 ;Calculations TEXT 632 496 Left 3 ;LC bandpass filter calculations TEXT 736 -272 Left 4 ;Instructions TEXT 608 -216 Left 2 ;click on run\nthen click on "incoming_signal" to plot it.\nthen click on the plot window then on plot settings / add plot pane\nthen click on "bandpass" to plot it\nthen click on the plot window and plot settings/add plot pane\nthen click on "out" to plot it TEXT 608 72 Left 3 ;The diode RECTANGLE Normal 240 736 -496 416 2