LIMA-SDR RX

Read the last words down the page !!

Top of RX pcb

Bottom of RX pcb.

First the parts for the power supply.
There are some changes in this design, I read this on another site. 
http://www.dj0abr.de/
To prepare the RX for PA, so why not doing it now.

So I replaced the coil L1 with a wire, and placed an Elco 10uF/16V parrallel to C4 on the bottom site of the pcb.

I finished the first part (4.1 Bestuckungsplan Schritt 1) of the manual and checked the measurements as written.

Measuring PointManualAs BuiltRemark
Power supply12,00 V12,05 V 
MP15,00 V4,91 V 
MP23,300 V3.298 Vexchanged LM317T for LT1086CT 3,3 V
MP35,00 V4,91 V 
MP411,2 V11,35 V 
MP511,2 V11,35 V 
MP62,08 V2,08 VSet with trimmer R21
MP76-8 V6,20 VVariabel.

As far as now the pcb is using 16,2 mA.

Placed the ic-sockets, now I am waiting for the Si-570 to arrive.

As you see the Si570 is arrived and placed on the pcb

On MP 1 you must have a frequency of 15 MHz, and this is what I measured.

After that I placed the rest of the parts as described in the manual part 3.

I tested the usb connection, and get data from the Si570,
I also can change the frequency, so everything is working.

Starting Part 4 of the manual, 
placing the heating resistors on the Si570, with between them the NTC's to regulate the temperuature.
When it starts up the current was 160 mA, when the temperature was rising the current drops.

Part 5 of the manual is the frequency preperation.

Measure PointManualAs Built
MP 1
8 MHz
8 MHz
MP 2
4 MHz
4 MHz
MP 3
2 MHz
2 MHz
MP 4
1 MHz
1 MHz

Part 6, the IQ-mixer.

Close up !

I connect the antenna and power and as described in the manual I hear signals, so far everything is working well.

The next stap in the manual is to make the 80 meter band preselector.

It's working well, down and up the 80 meter band the singnals are dropping, so manual part 7 is ready.

Part 8 is the pre-Amplifier of the lima-sdr, on this point when it is activated the current of the sdr is 260,6 mA.

On the next picture, you see the bare signal of the sdr, check the signal level, almost 4 and -70 dB on the noise floor.

On the next picture you see the Pre-amplifier enabled, signal level almost 8 and -50 dB, so the predicted 20 db gain is correct.

Part 9 of the manual is the controler of the pre-selector.

The next tabel is to check the voltages on the measure points.

Measure point = 0VFrequencyJumperposition JP1Frequentie multiplierAs built
MP1
0,25 - 0,59 MHz
3
16
0,22 - 0,58 MHz
MP2
0,59 - 1,18 MHz
3
16
0,59 - 1,17 MHz
MP3
1,18 - 2,16 MHz
2
8
1,18 - 2,14 MHz
MP4
2,16 - 4,11 MHz
2
8
2,15 - 4,10 MHz
MP5
4,11 - 8,22 MHz
2
8
4,11 - 8,21 MHz
MP6
8,22 - 15,06 MHz
2
8
8,21 - 15,04 MHz
MP7
15,07 - 22,10 MHz
1
4
15,05 - 22,08 MHz
MP8
22,1 - 30,00 MHz
1
4
22,09 - 42,10 MHz

So there are 3 options to use this SDR, these setting must be set into the software and on the SDR-hardware.

Jumper postion JP1
Frequency multiplier
Frequency span
1
4
2,5 - 30 MHz
2
8
1,25 - 25 MHz
3
16
0,625 - 12,5 MHz

Part 10 of the manual Preselector filter 0 - 0,5 MHz.

Part 11 of the manual Preselector filter 0,5 - 1 MHz.

Part 12 of the manual Preselector filter 1 - 2 MHz.

Part 13 of the manual Preselector filter 2 - 4 MHz.

Part 14 of the manual Preselector filter 8 - 15 MHz.

Part 15 of the manual Preselector filter 15 - 22 MHz.

Part 16 of the manual Preselector filter 22 - 30 MHz.

It's working fine.

Two day's later I was listening with the SDR and suddenly (I wash nothing doing with it) it began to smoke and everything was destroyed and also the equipment which were connected to the USB hub such as the Softrock SDR and the USB Soundcard. So this LIMA SDR project was and is the last homebrew project I ever done. I quit homebrew projects from now one !!

 

If anyone have comment or suggestion please feel free to mail me, I appreciate it !!

73
Arie