Category Archives: Electronics - Page 22

Amp work continued

Yesterday and today I did some more work on the amplifier control. I milled new plates for the stepper motors and gears, I milled a D shaped hole in one of the gears and I assembled everything and tested it together with the rack unit which contains the electronics. It all worked well after a few changes in the software. So now during some rainy day I will attach it all to the amplifier and test if it works well. If not I’ll fix it 😉

I also made three plates made out of stainless steel which will be used to attach the lightning protection to the tower. Today everything is connected below the base bearing but I am afraid that if I get a direct hit on the tower I might weld the bearing which would mean lots of problems. These new plates will instead be attached above the bearing to the legs of the tower and are made out of stainless steel since this works well with both galvanized steel and copper.

A shitty welcome

When me and Teemu (SM0W) arrived at SJ2W today after a nice weekend in Umeå at an SSA ham meeting and I got down into the basement I was met with 10cm of water on the floor with poop floating around. Luckily it was about 2cm from the granger amplifier so we arrived just in time. After a few hours of work from a clean up crew they did emtpy the crap-well. So now we will see how much I get from the insurance company but luckily no radio gear was damaged. However one room in the basement has got a wooden floor which is now ruined. This kind of sucks the motivation out of me and we will see how much money I will have left after this for antenna projects, might need to put all the plans on hold (aaargh!).

Anyway, I showed a video tour of SJ2W during this ham meeting and I have published it on youtube. Currently it is in Swedish but I have plans to make a dubbed version in English.

Components placed

Today I spent some time at work again. I felt like putting components to the in-band QSX system and now it is soon ready to be programmed and tested. I realized though that I had forgotten to put a driver chip for the external transfer relay which will be used to transfer the in-band radio to transmit with the run radios amplifier and antennas. However, it is an easy fix just putting a couple of FETs onto the transfer relay and use a couple of the AUX I/O I routed out to a header, in case I needed extra I/Os in the future.

Now I need to order some connectors and switches, so that I can finish up the maneuver boxes and start programming it. I will mount it in a 19″ rack box which will also contain the transfer relay and dummy load which will be used if the “wrong” radio transmits at the wrong time.

Stay tuned…

Milling PCBs and power splitters built

Today I spent some time at work. I needed to mill a board for work, but mainly to test that the through hole plating system works properly, since the last time we used it some vias were broken. This time though it looks very promising, but we will see when I assemble and test the boards. I decided to add some own designs to fill the panel, so I did add a sound card interface I’ve designed with a Winkey 2 chip, audio isolators, FSK support via a FT2232 USB chip which creates two virtual COM-ports.

I also added the in-band QSX electronics to the panel, which will hopefully this summer make us able to work in-band QSOs for real. I also got a couple of transistors from a friend at work (from mini-circuits) that I will use to build a 25dB preamp to be used to compensate for the cable loss. We are going to put up a vertical about 400m from the house using RG-59 as coax as a start to test how well it works on 20-10m. We will later extend the system using a small loop with the NULL towards our TX antennas. More information on this when I am putting the system together.

I also built a couple of power splitters. Or actually one of them is for 160m and does not contain the option to power split, its a regular 2×1 switch but with an A/B output making it possible to route it to both 6×2 switches, which means to any of the four operating positions. The other box is for 10m to replace the one at SJ2W which has got some funny problem which I have not been able to find. So I will replace it and see if the problem goes away, if so I will fix that splitter and make a new UN-UN for it with 6 windings so its optimal for 80m. I use 4 windings on 10m. I put the 7/16″ connectors in the lathe to make them fit into the PCBs. The connectors were donated by SG3P, thanks Gunnar! He has probably donated 90% of all 7/16″ chassis female connectors at SJ2W. I did order a few from China, very cheap so we will see the quality if they are good enough to be used at the station.

I also removed some BNC-connectors from old research projects that I will use on the in-band QSX electronics.