13 March 2014

WSPR-Bone: Towards a dedicated WSPR-Computer 01

It is fun to play around with your gear. And when you have all that you need to go on the air, things are getting kind of boring. Computers are running and the software keeps evolving and propagation is down and you are not in the mood to wait two hours for the next QSO.

©  Joachim Lehrer

Then came the Ultimate and everything changed ... at least for me. In the meantime I have the Arduino QRSS, Ultimate2 and Ultimate3 (Just look in my blog under WSPR) and the fascination isn't gone. You can communicate with the world with a gadget that fits into a packet of cigarettes. It needs nearly no power and you can experiment with power levels never dreamed of. And when another Om who lives nearby showed me his case of his Ultimate, I was mesmerized.

 Goal
So I decided to build a WSPR-Station with everything included and without using the big laptop or computer. So what did I need.

  • Of course the Ultimate 3 and Low Pass Filters for nearly every band.  OK.
  • An antenna tuner to match the antenna when the Ultimate changes the band. I have an Elecraft T1. OK.
  • The antenna tuner should be switched automatically by the Ultimate for I do not want to stand by and change every 2 minutes the matching system. To Be Done. 
  • Goal : Being a real beacon which makes observations of band conditions a snap.  Partly Done , when my antenna doesn't need any matching for it is tuned.
  • A step attenuator which lets me experiment easily with various power levels. I have the assembled kit from Dirk Hendriks. OK.
  • Goal: Being a real beacon which turns down power levels every two minutes. To Be Done. I have an idea, that the LPF boards could be used for these purposes. Instead of building the LPFs, I think that I can build an additional board using well defined attenuation steps.
  • Measurement of power levels had been a problem, but was solved in the meantime. OK
  • Uuups: I forgot - see down below: I have only one antenna and sometimes it nice to listen to the band. So I need a switch between the Ultimate and a receiver. I already have a magnetic loop in my room which has an automatic switcher build in. But it is broken in the moment. And I have a Magic Box from the 4SQRP-Group, but I have to assemble it. Halfway Done.
So I think, that I have nearly everything concerning the radio hardware. Of course there are still a lot of things to be done.
  • And before I forget it: I need a nice case. To Be Done!!! And believe me, that will be the hardest part.

Computer

Why would I need another computer, when I just wrote, that I didn't want one. This riddle could be solved very easily. What do I do when the Ultimate is sending and resting. I could sit there and stare at the blue LCD screen. In fact this could be fascinating, especially when in the next release of the software I will get some kind of information about the satellites from the GPS . But on the long run ...
Did I tell you, that I want to make QSOs? For me my WSPR transmission and the report from the other station is some kind of QSO. So I have to get that report. I could use the laptop, but that's not really an adequate Partner for the little rig.

So it boils down to the Arduino, the Raspberry Pi or ...
The Arduino is a powerhouse if you want to connect a processor to the real world. Programming is easy and you don't have to deal with operating systems. You can concentrate on your task. That's nice and easy. And when I saw the project Cascata with the Arduino One I was sure, that part of my ideas could be developed with an Atmel processor. (By the way, the same which is working in the Ultimate.)

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So I ordered the LCD screen, but I could not get the original one and bought a clone... Nothing was achieved. WA5ZNU had optimized the code, the clone used another library in short I didn't manage to get this software working and the display was a kind of game display. Nothing really serious. Sorry, although in the moment M0XPD is developing a TRX on an Arduino Due.

So back to the Raspberry Pi which is a real gem, but it is slow as hell. Still, I wanted to give it a try and I bought a display which seemed more appropriate for the project. But it turned out that it worked as promised, but you had to load special drivers and patch the kernel. And: If you made your normal update/upgrade routine everything is lost and you have to reinstall it. Too much trouble for me and I will try to use it with an Arduino. Beside that a touch display with these dimensions are a pain for my big fingers.

So I looked for another embedded Linux systems which would be faster and better. You have a lot of choices. First I thought about the UDOO. It is said that you get 4 Arduino Uno + 1 Arduino Due and a Linux system and Audio Input, which nearly all other boards are missing. But when I read all the reviews it boiled down to: You can not program the Arduino part on the UDOO, takes 10x times to compile. The Audio input is not really supported and when you count 1+1 together, you can by a used laptop for the same money. And the community seems to get stuck. No real movement compared to the Raspberry Pi environment.

The next option would have been the Arduino TRE when this board would have been available.

I will not go through all boards which are on the market. They all had their advantages and their drawbacks. I made a decision.

I opted for the BeagleBone Black BBB which seemed to have all the specifications I needed and it was told, that the system is fast. At least faster than the Raspi. One thing I noticed: All those reports - OMG Most bloggers just looked at the relevant web sites and copied the contents. Seldom I did find a real benchmark, which could be trusted.

But I have the hope to use a system were WSPR, Fdigi and other ham related software could run.

More to read:



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So Stay Tuned!