Here’s the SV1EIA usb2sdr board controlling the Si570 chip on the vfo kit from K5JHF/K5BCQ, the MCU and display unit are of course removed. And the Si570 board is clocking the LA6NCA QSD unit. I haven’t calibrated anything yet, but it works fine.
Archive for the 'Electronics' Category
Yesterday I received the Si570 Controller and Frequency Generator Kit by K5JHF and K5BCQ.
And today, after 3 to 4 hours work the kit was ready for a test spin. My unit has the LVDS Si570 chip, the FIN-1002 LVDS to LVTTL converter with the TC1-1TG2+ output transformer. Here are a few pix…..
There has been some interest in the Picaxe GPS NMEA-0183 Decoder which I use to time the keying of my wpsr beacon.
The Picaxe chip decodes the time data in the $GPGGA sentence from the GPS unit and then print the UTC time on the lcd display. In addition it set a output at the start of every even minute for keying the wspr beacon. That’s all it do with the current 18X chip.
I am planning an upgrade to the 18M2 chip which is a lot more powerful and has got more functions then the current 18X chip.
With the 18M2 I am planning to display some of the other GPS information, like position, signal strength, number of satellites, etc. It’s not that the 18X chip can’t do this extra information bit. But these task will put a lot more strain on processing and communication so I fear the accuracy of the keying will suffer.
 >> Download full size scheme <<
; ************************* Picaxe Project ************************
; *****************************************************************
; Filename: GPSDO Display unit v0.4.bas
; Date: 25.02.2012
; File Version: 0
; Written by: LA6TPA Geir Aarnes
; Function: Decode NMEA data from GPS unit
; Last Revision: 4
; Target PICAXE: 18X
; *****************************************************************
;
; Revision history
;
; Intitial code GPSDO Display unit v0.1.bas
; First working version GPSDO Display unit v0.2.bas
; WSPR trigger added GPSDO Display unit v0.3.bas
; Code cleanup GPSDO Display unit v0.4.bas
; *****************************************************************
#Picaxe 18X
SETFREQ m8
symbol GPS_RxD = 0 ;NMEA data from GPS module
symbol GPS_1PPS = pin7 ;1PPS signal from GPS
symbol GPS_TxD = B.0 ;NMEA data to GPS module
symbol WSPRtrig = B.1 ;Triger output for WSPR tx start
symbol tByte00 = b0 ;Byte for temorary data
symbol LcdByte1 = b1 ;Byte used by LCD routine
symbol LcdByte2 = b2 ;Byte used by LCD routine
symbol tByte03 = b3 ;Byte used by LCD routine
symbol tByte04 = b4 ;Byte for temorary data
gosub init ;initialise LCD
pause 10000 ;wait for GPS to boot
serout GPS_TxD,T4800_8,(13)
serout GPS_TxD,T4800_8,("$PRWIILOG,???,V,,,",13,10) ;turn off all GPS output
serout GPS_TxD,T4800_8,("$PRWIILOG,GGA,A,T,1,0",13,10) ;activate GGA sentence
let LcdByte1 = 1 ;set b1 to ‘clear display’ instruction
gosub wrins ;send instruction to LCD
main: serin GPS_RxD,T4800_8,("$GPGGA,"),B8,B9,B10,B11,B12,B13 ;wait for $GPGGA then receive 6 bytes into B8..B13
;debug
IF b13 <> "0" THEN GOTO LBL01 ;Check lower part of seconds, skip if not == 9
IF b12 <> "0" THEN GOTO LBL01 ;Check upper part of seconds, skip if not == 5
tByte00 = B11 - 48 ;Read lower part of minute and convert ASCII to binary
tByte00 = tByte00 & %00000001 ;Mask bit 0 which indicates an ODD minute
IF tByte00 <> 0 THEN GOTO LBL01
high WSPRtrig
pause 500
low WSPRtrig
LBL01: LcdByte1 = 1
gosub wrins
LcdByte1 = "U"
gosub wrchr
LcdByte1 = "T"
gosub wrchr
LcdByte1 = "C"
gosub wrchr
LcdByte1 = " "
gosub wrchr
LcdByte1 = b8
gosub wrchr
LcdByte1 = b9
gosub wrchr
LcdByte1 = ":"
gosub wrchr
LcdByte1 = b10
gosub wrchr
LcdByte1 = b11
gosub wrchr
LcdByte1 = ":"
gosub wrchr
LcdByte1 = b12
gosub wrchr
LcdByte1 = b13
gosub wrchr
goto main
init: let pins = 0 ;Clear all output lines
let b4 = 0 ;Reset variable b4
pause 200 ;Wait 200 ms for LCD to reset.
let pins = 48 ;Set to 8-bit operation.
pulsout 3,1 ;Send data by pulsing ‘enable’
pause 10 ;Wait 10 ms
pulsout 3,1 ;Send data again
pulsout 3,1 ;Send data again
let pins = 32 ;Set to 4-bit operation.
pulsout 3,1 ;Send data.
pulsout 3,1 ;Send data again.
let pins = 128 ;Set to two line operation
pulsout 3,1 ;Send data.
let b1 = 12 ;Screen on, cursor off instruction
gosub wrins ;Write instruction to LCD
return
wrchr: let pins = b1 & 240 ;Mask the high nibble of b1 into b2.
high 2 ;Make sure RS is high
pulsout 3,1 ;Pulse the enable pin to send data.
let b2 = b1 * 16 ;Put low nibble of b1 into b2.
let pins = b2 & 240 ;Mask the high nibble of b2
high 2 ;Make sure RS is high
pulsout 3,1 ;Pulse enable pin to send data.
return
wrins: let pins = b1 & 240 ;Mask the high nibble of b1 into b2.
pulsout 3,1 ;Pulse the enable pin to send data.
let b2 = b1 * 16 ;Put low nibble of b1 into b2.
let pins = b2 & 240 ;Mask the high nibble of b2
pulsout 3,1 ;Pulse enable pin to send data.
high 2 ;Back to character mode
return
Here is a line of homebrew circuit board that I have made for a amplifier project I am working on. (Which by the way takes forever to comlete
 )
These boards are designed by Dominique F1FRV which have laid down a tremendous effort in designing these boards.
Dominique has done some minor changes to the design since these boards were made, so cards made by his latest instructions will look a bit different from these.
- Home brew PCB’s ready for population
- Logic controller
- G2 supply
- HV & G2 Sequencer realys
- HV METERS & TRIP
- Slow starting filament voltage contoller
- 1st grid and antenna relay power supply
I have put my wspr beacon on the air for a test after the latest modifications. And so far it look promising.
Here is a picture of the mess

Picaxe wspr beacon. Bottom: Picaxe and DDS-60 :Top from right: 10MHz LPF, tripler and amplifier for clocking the dds-60 @ 30MHz
Here is a small update regarding my band hopping picaxe controlled wspr beacon.
I took the beacon of air the other day to do some revisions to it’s circuitry. And in this context figured out that I was in need for a filter to clean up the square wave shaped signal from the 10MHz reference oscillator, the GPSDO MKII. I did a little googling and found an interesting circuitry drawn by Jerry Mulchin – N7EME. The reason for needing this filter is that I have a passive frequency trippler for clocking the DDS-60 @ 30MHz, and this tripler need a sine wave to work right.
There is still some work to be done before I can put the beacon back on air. But as they say in broadcasting; Stay tuned, will be right back after….
Here is a Hi-Pot tester I have just finished.
Hi-pot tester is good for 11Kv at the terminals and the leakage current is 3uA.
I’m pretty happy with the result.
I’m trowing in a couple of pictures of the FOX DELTA ST2 Antenna Tracking Interface that I have build.
Unit works great, but on the bench for the moment. Antennas ain’t finished yet. ![]()
I’m in the proccess of building a 144Mhz 4×7-Element-Yagi array for EME. ETA not known.

























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