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0-30 MHz SSB/CW/FM/AM/DRM Receiver based on DDS and RISC

Shortwave Capture

0-30 MHz SSB/CW/FM/AM/DRM Receiver based on DDS and RISC
As a special treat for all radio amateurs we present a general-coverage AM/FM/SSB receiver with a wide range of features, which uses a DDS chip in the VFO section and also has a DRM output that can be fed into a computer. The receiver is controlled by a modern 8-bit Atmel RISC processor. The frequency readout is on a clearly legible 7-segment LED display.
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Gerber file

CAM/CAD data for the PCB referred to in this article is available as a Gerber file. Elektor GREEN and GOLD members can exclusively download these files for free as part of their membership. Gerber files allow a PCB to be produced on an appropriate device available locally, or through an online PCB manufacturing service.

Elektor recommends its business partner Eurocircuits as the company of choice for its own prototypes and volume production in selected cases.

Extra info / Update
Although the AT90S8515 used in the project is no longer recommended for new designs, it is still generally available (December 2006). A suggested replacement is the ATmega8515, which offers AT90S8515 compatibility thanks to its SC8515 compatibility mode fuse.

Inductors L11 and L14 have been transposed on the component overlay. This may be corrected by transposing the component references in circuit diagram Figure 2. In the components list, L11 should be marked as 1μH2.

The PCB design has a length of copper track missing at pin 19 of the MAX7219. The connection should be made with a piece of wire. Updated Gerber files were sent to ThePCBShop on 2 March 2007 The corrected parts list and PCB artwork (pdf file) may be downloaded from our website.

Depending on the response of the readout to fast turning of the rotary encoder, and the encoder used, the value of capacitor C40 may be changed a little.

Although on MIX1 the marking is with pin 6 instead of pin 1, the device can be mounted as shown because of its internal symmetry.

For SSB reception, the amount of frequency pull that can be obtained from the CSB455 device (X3) will depend on the exact type and brand. The CSB455 supplied by Barend Hendriksen and used in our prototype gave good results. Suggested methods of obtaining sufficient pull from nondescript CSB455 devices may be found on our Forum.

Component list
receiver board (030417-1)
PCB layout free from this project page
Resistors and Capacitors
see download 030417-PCBu.pdf
L1,L3 = 330nH
L2,L5 = 470nH
L4 = 100nH
L6 = 150nF
L7,L10 = 390nH
L8,L11,L13,L14,L16,L17,L18,L19,L21 = 100µH
L9,L22 = 820µH
L12 = 10µH
L15 = 1µH
L20 = LMC4100A or 0509-10736
TR1 = LMC4202 or 0509-10735
D1 = 1N4001
D2,D3,D4,D5,D6 = BA482
D7,D9,D10 = 1N4148
D8 = KV1235
T1 = BF991, SOT143
T2,T3 = BF992, SOT143
T4,T7 = J310
T5 = BFR93A, SOT23
T6 = not fitted
T8 = BC547B, TO92
T9,T12,T15,T16 = BS170, TO92
T10,T13,T14 = BF494, TO92
T11 = BF451, TO92
IC1,IC5,IC6,IC7 = NE612/SA612, DIP8
IC2 = MAR8 (Mini-Circuits)
IC3,IC4 = AD603AQ, DIP8
IC8 = MAX7400, DIP8
IC9 = LF356, DIP8
IC10 = LM380N-8
IC11,IC12 = 78L09, TO92
IC13,IC14 = 78L10, TO92
IC15,IC16 = 78L05, TO92
A1 = solder pin
K1,K2 = PCB mount cinch (RCA) socket
K3 = 3-pin header with flatcable
K4 = 4-pion header with flatcable
K5 = 2-pin header with lenght of thin 50? coax cable
K6,K7,M1,LS1 = 2-pin header or 2 solder pins
JP1 = 3-pin header with jumper, or changeover switch
X1 = 44.545MHz quartz crystal, parallel resonance, CL = 32pF
X2 = CSB470
X3 = CSB455
MIX1 = ASK-1 DIP6 (Mini-Circuits)
FL1 = 45G15A1/B1
FL2,FL2A = SFR455J
FL3 = SFR455H
FL4 = SFR455E 100µA or 150µA moving-coil meter, (S-meter), connect to M1
8 Ohm/2 W loudspeaker, conenct to LS1
Enclosure, Bopla Lab, dim, 223 x 199 x 56 mm (Conrad Electronics # 523348)
PCB, order code 030417-1 from The PCBShop

microcontroller and display board (030417-2)
PCB layout free from this project page
Resistors and Capacitors
see download 030417-PCBu.pdf
L1-L9,L11 = 100µH
L10,L12,L13 = 10µH
L14 = 1µH2
L15,L19 = 330nH
L16,L20 = 100nH
L17 = 820nH
L18 = 1µH
T1 = BC557B, TO92
IC1 = AT90S8515-8PC, 40-pin PDIP, programmed, order code 030417-41
IC2 = MAX7219CNG; 24-pin narrow DIP
IC3 = AD9851BRSZ; 28 ld SSOP
IC4 = 74HCU04; 14-pin DIP
IC5,IC7 = 7805; TO220 case
IC6 = 78L05; TO92 case
LD1-LD6 = 7-segment LED display, common cathode, height= 13mm (e.g. SC52-11GWA)
S1 = rotary encoder; 24-30 pulses per revolution
S2-S17= pushbutton; 1 make contact, e.g. D6 or equivalent (Conrad Electronics)
X1 = 8MHz quartz crystal, CL par.= 32pF
X1 = 10MHz quartz crystal, CL par. = 32 p
K1,K2 = 8-pin header; interconnect using flatcable (e.g. Conrad Electronics # 741256)
K3 = 7-pin header; connect to K3 and K4 on receiver board
K4,K5 = 5-pin header; interconnect via flatcable (e.g., Conrad Electronics # 741230)
K6 = 2-pin header; connect to K5 on receiver board via coax cable
PCB, # 030417-2 from The PCBShop
Source code and hex file for this project not available due to licencing.
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