SJ2W Contest Station

I have worked a bit lately on the power meter for the openASC project. I did some tests today with the openASC control box hooked up and I think it looks pretty nice. The high VSWR is probably because the power meter sensor is just calibrated on forward power, I need to calibrate the reflected power as well. These sensors send out data of which kind of sensor it is so depending on its power range the scales on the openASC box automatically changes. The openASC box just needs to know what address the pickup corresponding to the box has got and it will show power from that sensor. It is also possible to configure the update rate of the display, how fast we wish to bargraph to change and also the text values, which is also configurable between peak power and average power.

Check the video for a small demo,

Posted under Electronics, openASC

I had SM3SGP up here from Thursday to Monday. We built openASC devices for his station since he is going to implement that at his big contest station http://www.sk3w.se. We had a lot of fun even though it was stressful at the end. I estimate that between 4000-5000 components were placed. There are some pictures on his website.

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This weekend I hope that we have enough people to put up the broken 80m vertical again. I need to drill a bigger hole in the aluminum bottom but otherwise it is pretty much ready to be put up. Other plans are to finish up the 2nd 6el Yagi for 20m and try to find a problem with the current 6el yagi, there is some bad connection somewhere, hopefully in some connector. I will try to post some pictures during the weekend.

Posted under Electronics, openASC

I did some EMC testing of the openASC electronics, to make sure that I won’t get any problems when installing the system at the station. This was done in our own lab at work and I did find some small spurs but nothing big. I had the antenna located about 30cm from the electronics while the standard I was comparing to said it should be 10m away, so I had quite some margin I was mainly interested to see where they were located and used a IC-735 to listen to them to see what kind of level we were talking about. I could hear the system clock at 14.756 MHz but quite weak and it’s outside the ham band.

On Thursday evening me and the gf went down to the radio QTH with a car filled with stuff. I had the cabinet for the 20m stack with me and all the stuff for the openASC-system, including the oak shelf as well. I spent most of Thursday and Friday cleaning out the shack, removing pretty much all equipment, cleaning it up and adding back the stuff to be used again. I installed the openASC box meanwhile and the driver modules in the basements on Friday and in the evening the system was up and running, with nothing connected however.

On Saturday I moved the coaxes from the shack out to the switch room and hooked up the 6×2 switch, marked up the terminal blocks in the switch room to make it easier to keep track of what is connected where, and hooked up the coaxes to the switch. In the room where the driver modules were located I pealed off the isolation of the 2 60-leaded cables and hooked up the 6×2 switch to one of the driver modules. When this was done I went up and configured the openASC box with the configuration software and it worked UFB. I had the system running for some 30+ hours straight without any noticeable error. However the automatic BCD band decoding did not work, I have some software bug in the internal communication between the two micro-controllers within the openASC control box that I need to fix. There are parts of the code which aren’t finished, but the openASC bus protocol now seem to run very stable *knock on wood*. I also hooked up the beverage switch to a driver module located in the shack and it worked well. So now I am able to select bands manually and also beverages.

Below are some pictures with descriptions

EMC tests

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Pictures from the weekend

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Posted under Electronics, openASC

I did build a new shelf for the radio shack now when I am about to install the new openASC control system that is finally getting ready to be used, if however not completed but functional. The idea is that all radio positions have the openASC control box to the right of their monitor. On the SO2R position however, I wanted to be able to easily reach both radio 1 and radio 2 antenna control. So I decided that on multiplier radio #1 (SO2R radio #2) the openASC box is on the left of the monitor instead, thus enabling the SO2R operator to reach its controls.

Stacking boxes is always tricky so I decided to build a small shelf made out of aluminum and oak which I think came out pretty fine.

I will do some EMI tests on the system this week, since we have that ability at the university to make sure we won’t suffer from any spurs showing up on the ham bands. If that looks good, I will take everything down to SJ2W this weekend to install it.

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Posted under Electronics, openASC