Today I spent some time welding together the pieces I cut yesterday to a casing on wheels. I got it pretty much perfectly straight which I am very happy about but it was some work to get there. Now I will need to remove the paint so I can repaint it so it looks pretty. When I have grinded down the welds I will put the sheets on it and drill the holes. I also need to add some support inside for the transformer etc.
SM0W, SA0AZT and SM0SHG came up to spend the weekend at the lab at work building antenna switches and I finished up the openASC-boxes for SK0UX. It was a lot of fun and we got lots of stuff done. They still have quite a bit of work to do but they got with them the openASC boxes as well, so now there are three stations in Sweden using the openASC system, SK0UX, SJ2W and SK3W.
It also seems like I am claimed #1 Europe on 20m SSB in WPX SSB which is a lot of fun!
I also did some tests to test if the theoretic Q-value of the PI-filters we use in amplifiers correspond to measurements done with the VNA. It did not match at all, I got the values 4 times higher when having Q-value of 12 on the VNA compared to the theories. However I need to do more thinking and testing on this to figure out why. Maybe somebody can explain? I used the -3dB bandwidth to calculate the Q-value.
I also spent time cutting metal for the power supply for the amplifier project. I’ve collected some material at work which would have been thrown out and used it for the amp. I also bought some wheels that will be mounted to the amp which limits the weight of it to 400kg, but I should have quite some margin 🙂
I got a few boards today that SA5BJM wanted me to design and since I needed them for my own project I did. The G1 board is based on a DC9DZ design which I modified some values to suit the QBL amplifier. I haven’t tested it, I am missing a 230->110v transformer that currently is at SM3WMU QTH since he transported it from SA5BJM when he was south last weekend.
I also tried the anode choke. First I had 4 sections (no real need to wind sections for this since I have a ferrite, but I did anyway) and got 800uH indutance so I changed to 3 sections and got about 550uH. I did some quick measurement and seems like I have no resonances below 30 MHz which was the goal.
Tomorrow I am heading down to SJ2W and I will be QRV SOSB 20m this weekend.
Today I got more work done on the chassis for the QBL amplifier. I had forgotten my phone at home yesterday so I could not take any pictures, but I did take some today instead. I got the HV rectifier assembled, made an anode choke out of teflon and 61-material ferrite rod. The idea is to get a lot of inductance without needing to get any resonances under 30 MHz.
I also got the L-iron welded together and now it’s ready for the aluminum side plates.
