Monthly Archives: March 2012

More electronics

I’ve been a busy boy and built a USB-dongle for the openASC bus. This dongle can be used to communicate straight out to the bus. I had a previous version of this that needed external 12v to be able to transmit, but I made a new version with improved bus filtering but the main new feature is a step up converted which makes 9v out of the 5v that the USB port supplies. That way it can operate on its own without an external DC supply.

I also did more work on the amplifier project. I mounted 2 pcs of small relay boards which will be used to switch the input filtering plus also the relays that switch the output PI-network of the amplifier. I found this to be the easiest way to solve the issue of switching 12/24v relays since the amplifier control board had ULN2003A drivers to drive these small 12v relays. I also soldered lots of cables, so now the control panel is hooked up to the micro controller and soon its time to actually start writing the code, not that much too do on the electronics. I need to add another relay board to be used to switch ON/OFF the amplifier, toggle HV etc. plus I will need to hook up the potentiometers used to position the capacitors of the PI-tank to the control board.

All PCB info uploaded

I have now uploaded all the information for the circuit boards that I do sell, so check it out!


New SM record

                    CQWW WPX Contest, SSB

Call: SJ2W
Operator(s): SM2LIY
Station: SJ2W

Class: SO(A)AB HP
QTH: Da Traesk
Operating Time (hrs): 36

 Band  QSOs
  160:    0
   80:   69
   40:  438
   20:  854
   15: 1098
   10:   50
Total: 2509  Prefixes = 1102  Total Score = 6,516,126

Club: Worldwide Young Contesters


Started quite OK, but Aurora started saturday morning.
Much better conds on sunday, even 10m had some openings in the
morning to Asia.
15 was fine on sunday during all day.
Best NA-conds on 20m in the end of the contest.
TNX for QSOs. QSL LOTW, EQSL or direct via SM2LIY.
CU in CW part, M/S.
Per / SM2LIY

More PA automation progress

Today I spent about four hours in the lab fixing some stuff for the PA automation. I did solder cables with pull-ups and decoupling capacitors in the control box and also added connectors to those cables. I made sure to label them at once so that there are no mix ups in the future which might cause failures. I also soldered the cables for the 230v supply voltage for the three different switches power supplies and tested them, they seem to work fine. I also added a fuse for the 230v (2A). The stepper motor driver boards got 10v zener diodes to protect the driver MOSFETs. I used regular flyback diodes first but since they “consume” the same amount of current when turning the motors manually the motors had quite a lot of torque making it hard to turn them by hand. So with the 10v zener diodes that problems goes away and I can easily turn them by hand. Since the idea is to make the amp manually tunable and then just save the positions, they need to be easy to turn.

Some blurry pictures