My radio blog

openASC progressHam radio

Posted by Mikael Larsmark 2008-04-26 00:53

The box seem to work so far. I have been needing to do a couple of modifications because of sloppy errors but otherwise it's working as expected so far.

I recorded a little video while I was testing all the functions on the front panel. The LEDs will not be flashing when the code is done but here is a sample of how it looks.

Click here for a short video

Think the logo looks pretty nice too :)

Stay tuned...

openASC mainbox assembledHam radio

Posted by Mikael Larsmark 2008-04-24 22:23

Now I've assembled the openASC manouver box and so far everything is OK. I had to do one minor modification but if it stays with that one I'd be extremely happy.

Tomorrow I will start to do some testing on the different functions. I will try to investigate if the hardware is OK before I go into doing some more "deep" programming.

Here are some pictures of the assembled cards

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To be continued...

Reflow soldering rocks!Ham radio

Posted by Mikael Larsmark 2008-04-15 23:12

When you get used to have access to such a lab I have at work you really get spoiled. Most of the stuff I build today I use the soldering oven to "cook" the cards and the result is great and you build a card probably five times as fast compared to when you solder it by hand, if not even faster.

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Tomorrow I will start testing the communication interface. Everything seem to work on the card. If I activate all the outputs the voltage regulator gets a bit warm but it's nothing to worry about. I do however use very little current for the LEDs so I am considering gettiing some high intensity ones for the next card.

Here is a bad picture taken with my mobile phones camera when I have it connected to the STK500. I need to make a bootloader that work over my communication bus later so that I can update all the modules without connecting the ISP.

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openASC progressHam radio

Posted by Mikael Larsmark 2008-04-11 22:25

The source driver module has been ordered and assembled. Tomorrow I plan to do the first tests with it and see how well it works. I assembled some small USB-dongles that I ordered PCBs for as well which seem to work. With those I can hook a computer up to the control bus and use the computer just as an openASC device which is perfect for operating a whole station remote.

The driver modules have 20 outputs which pair wise can source up to 2A (drivers handle 4A but fused with polyswitches at 2A) so you can run 2A with one output or 1A on two outputs. No configuration of the driver board is needed, all that you do is set the offset address with a DIP switch.

The communication bus uses the same principle as old coax ethernet. You terminate each end of the bus with a 50 ohm termination and it drives 120mA into the bus which gives a very good looking signal which handles interference very well. This will be tested hopefully this summer in a real contest enviroment.

Here are some pictures of the source driver:
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Stackbox progressHam radio

Posted by Mikael Larsmark 2008-03-16 19:06

Now the box is almost finished. Most of the hard work has been done, what is mainly left now is to install all the control cables, the PCB for those control cables and also I need to change all the screws to stainless steel ones so they don't rust. I also need to order some enamelled wire so I can wind the transformer that should be placed on the piece of plexi glass you can see in the box.

I did silver plate all the copper strips inside the box to avoid corrosion.

I am very curious to see how well the box performs. I will probably have some insertion loss since the strips between all the relays aren't matched but hopefully it won't be too bad.

Here are some pictures
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To be continued...

Stackbox progressHam radio

Posted by Mikael Larsmark 2008-02-20 19:55

I recieved the vacuum relays from HA1AG the other day and decided that it was time to start building the 20M stack box with out of phase function on two of the three ports. I didn't find any good boxes for decent prices so I took an old box I found at work that had been used for an old research project, I just had to make a bottom, mid section and lid for it. It will not be water proofed but I will still have it inside a big cabinet up in the tower that supports other boxes as well.

Here are some pictures of the status of the project. I have done a bit more after these pictures were taken and I plan to do more work on it tomorrow and during the weekend.

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To be continued...

Recieved some stuffHam radio

Posted by Mikael Larsmark 2008-02-06 22:10

I got the 7/16" connectors today for the stackbox and hopefully tomorrow I will recieve the vacuum relays. Now I need to find a box so I can start building it. The 7/16" connectors are a bit strange though and might need to be modified a bit for it to work, hopefully.

Also I did visit EISCAT radar facility in Kiruna for research in the beginnig of this week and check this link out, especially the movies when they turn the big dish around. The diameter of that thing is 32m!

Working on a project - openASCHam radio

Posted by Mikael Larsmark 2007-11-28 22:32

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I was working on one of my big projects during the whole weekend. I am buildling a open source project similar to the SAC X box that YT6A has created. I got this idea a few years ago (you can see it on my homebrew page) about buildling a box to controll all antenna switching, rotators etc and communication run over a bus. It will have a lot of different features, the hardware is 95% finished and software development has started.

The plan is to make it open source so that if people are interested I don't need to do all the work myself, even though there will be an official release. I have not decided how to sell the hardware, but probably it will be in kit form. I will test to order PCB frontpanel (with labels etc) and see how good that looks, that is a cheap way of making a good looking front and backside, I hope.

The nice thing with this box is if you for example run a M/S, M/2 station you will be able to control everything from each position, so no more screaming about people rotating towers etc, you can do it yourself from the device on your operating position.

I did some programming on the graphical display and also did some work on the configuration software. The device will have inhabit function so that if you have a FT1000 for example the inhabit pin can be used to prevent any damage to antenna switches since the openAS can control when the radio should put out RF. That way you can even have TX/RX antenna combination without any worries to burn relays.

The display on these pictures are not the one I will use on the actual box. This is a spare PLED I had from another project, it will be a LCD on the openAS box with white background and black text.

This is an example of how it could look when having a big station. You can see the rotator indications on the right side and the inverted background on that 6/6/6/6el stack is that that antenna is currently used. If you have a multiband antenna, like the KT34XA and you select it, all other boxes will get a parathesis around it, which indicates that the antenna is currently in use by another radio.
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Here is a picture of the configuration software, written in java:
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I have also designed driver modules that can be used for up to 20 relays. All these are connected to a one-wire bus (similar to the old 10base2, ethernet over coax), so you can use reglar RG58 with BNC-T connectors etc to connect more devices. Both sinking and driver modules will be possible to use. All needed to be done with the addon modules is to set it's address, which is done with a 4 pin DIL switch on the board itself.

So stay tuned...still a LONG way to go before it's anything near finished.