söndag 16 november 2014



1.8" TFT LCD Display module ST7735S 128x160


The color on the TFT i not correct on this photo for same reason, sorry for that.
Just use level converter 5V -> 3,3 V 5 wires, CS, RESET, D/C, SCK and SDA.
Try the TFT sw in aurdino library Guide/TFT.

Next time i must find out if it is fast enough for S-meter update in next radio.
I am glad it works fine.


Minima main board started



The T/R switch is done. 5mA in Rx mode 45mA in Tx mode.
CW-Gen is done. 1mA when it is turned on. Output 10mV 720 Hz.

Tx/Rx, low = Tx  high = Rx, It is working ok if I/O is 3,3V.
CW-Gen if I/O is 3,3V R37 must be a lower value 47k > 27k, check T17c 6V.

Not much more to say about this.
The audio was to low for driving a speaker 140 m. So i must find a modification, i order some IC to tray. Next modification is to skip K2 LSB/USB relay.

The rest of the board will be the original design.


fredag 7 november 2014



QRP MINIMA DIGITAL BOARD



 



A complete logic to a all-band sw transceiver.
55 cm2   115 mA       Lo included  10 MHz - 260 MHz   around +16 dBm out.
I use a Spark-Fun Breakout board, i do not have RS232 on my computers.
I don't think the the pcb was aimed for adapt directly back of the lcd, but i find it possibility to do that, no wires just connectors.

I am really glad i came in to this project, Minima.
I used the test for LCD and I/O from AE5PH a few minutes after ended the soldering all is completed tested. I program in 10MHz, 3,75+20, 17.2 +20?   and 28.4+20 MHz for test.

I spend last weekend to measure the spurious, output level, and later phase noise.
I started this blog with the DDS-60 so i compared this to the Si570 unit.




Si 570 was around +16 dBm from 10MHz - 260 MHz. (10 dB atten to instrument)
DDS60 was 8.5 - 6 dBm out, 10 - 48.4 MHz

I use my home-breve spectrum analyzer.




And here is some phase nose measurements.




Si570  f = 10 MHz, Fnoise = 149dBc @ 10 kHz offset.
Si570  f = 23,75 MHz, Fnoise = 145dBc @ 10 kHz offset.
Si570  f = 37,2 MHz, Fnoise = 138dBc @ 10 kHz offset.
Si570  f = 48.4 MHz, Fnoise = 138dBc @ 10 kHz offset.
Si570  f = 144,3 MHz, Fnoise = 129dBc @ 10 kHz offset.

i think it is a relay good value.

DDS60 f = 23,75 MHz , Fnoise = 123 dBc @ 200-300kHz offset.

Here is the spurious list for Si570 @ 23.75 MHz

374665,-105.567
2.97076e+006,-105.015
3.30659e+006,-84.054
3.48848e+006,-105.268
4.47881e+006,-101.74
Nice values.

Here is the spurious list for DDS60 @ 23.75 MHz
432.174,-104.615
651.559,-105.865
866.931,-107.598
8217.29,-106.33
16483.7,-91.9783
19704.9,-94.6973
33065.9,-91.1369
38828.2,-93.0068
40964.1,-98.8106
48969.1,-78.3117
65155.9,-91.3816
83652.8,-84.6034
100000,-81.2614
115349,-84.2683
148096,-82.02
180225,-83.4377
197049,-79.2568
227295,-80.9892
248513,-71.561
297076,-77.092
342676,-72.7429
395275,-80.2696
424529,-80.6772
447881,-75.4794
545047,-80.7331
712382,-75.0742
738273,-74.7648
836528,-76.63
1.23886e+006,-75.5836


I also check the Output Z.
Si570 was 13 ohm  from 10MHz - 150MHz.
DDS60 was close to 50 ohm at 10 MHz and little higher @ 48.4 MHz.

I have never test so mutch on a LO signal, i enjoy to build and measure. 
No i lock forward to start with the main board next weekend.

This is the schematic for this PCB.



Thanks to Ashhar Farhan the designer.  
Thomas Sarlandie driver for Si570.
PP2KR Kleibe PCB-Maker, tanks a lot.