TX On 40m Takes Out NBN

So, for no apparent reason, lately transmitting on 40m has been causing the NBN to disconnect. It never done this before, nothing has changed with settings, the radio is in the same spot, using the same antenna and all that. So tonight while listening to the 7.130 dx net, i decided to do something about it. I got into the settings and changed the channel that the WIFI is operating on just in case that was the vector for RF overload, no change, so for stage 2, i grabbed a couple of 12mm clip on ferrites and wound as many turns of the power and telephone cable i could around them, problem solved. I can talk and internet again at the same time. For now 🙂

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When Your Opinions Do Not Matter

In a discussion of ideas, a range of opinions is probably a good thing to have, to find common ground see the pro’s and con’s of various idea and hopefully get the best outcome possible for the greatest amount of people. And this is a good thing, if you are talking about social issues or how to spend money etc. However, when it comes to scientific debate, like on climate change, your opinion is worth SHIT and what matters is the scientific evidence. And here is why:

When you get into an aeroplane you expect that the boffins at Boeing have used their slide rules, tape measures and calculators and Science’d the living shit out of the design, don’t you. If the CEO of Boeing came out and made an announcement like; This is Bill, Bill designed the wing on our new mega jet using his opinions, emotions and feelings, you would shit and never get into one of their planes ever again. Because that giant flying turd is more than likely going to kill someone.

The same going with Climate Change, your opinions, feelings and emotions mean absolutely nothing at all and if you think your opinion matters you are being wilfully ignorant to the extreme. Get the Actual Factual, you know, Science. And if you are too stupid, inbred or dumb to find and read the science, do what you do with everything else in your life you do not understand, defer to the bloody experts. And those experts are not the retards on Fox News or The Guardian, they are the actual scientists doing the work.

Every aspect of our modern society is built on science and you don’t impose your stupid opinions on those things do you. Its not like you have an opinion on how NASA should get get a rocket into space, or your doctor when he gives you antibiotics, and try putting opinions in your car rather than petrol and see how bloody far that gets you. Science, gives you all the things you take for granted in our modern society like that phone, tablet or computer you are reading this post on, your opinions did not build the internet or create the computer science did and yet you think you know so much more than actual scientists doing climate science, through experimentation and observation that you think it is your right to question and impose your opinions on Climate Change. That is wilful ignorance, arrogance and extreme stupidity.

Try shitting in your fridge and see how long that works for you. You know, before you get food poisoning or cholera and die because guess what, your opinions did not create our modern sanitation systems science did. Well, ignoring the science of climate change is exactly the same as that, shitting in your fridge. All because your ignorance and arrogance led you to believe that you know more than science does. And here is the place where you can exercise your opinions, what do we do about climate change? because the science is clear and real and has been that way for over 30 years.

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Arm Programming Cont

I was kind of thinking that the learning curve might be kind of steep. In fact for me its not all that bad, other than working out where everything is in the menu’s the process is rather familiar. I guess all those years programming on MUDS with GCC, GDB, Valgrind and friends using Kdevelop on Linux were not a total waste of time.

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Embedded Systems Programming Course

So a week or so ago i was talking with a friend of mine, Simon about how he was wanting to get into embedded programming and what that would entail. He had come across a series of youtube videos that take the unenlightened of us and walk us through many examples of becoming proficient with toolchains that allow for programming ARM micro controllers.

Now, I can do quite a bit of superficial programming in C using the arduino, but it does hold your hand quite a lot and its great for simple things, but if you want to do anything serious you really have to man up and learn how to use IAR Workbench or some GNU C toolchain along with all the associated hassles that come with that.

For sometime I have been using STM32 and ESP8266 micros but wimping out and using arduino for programming those chips, but after seeing this course on how to do ARM programming using the right tools, I have decided that its time to give it a go and see if I can get my head around the whole idea. So i ordered the TI development board from Element 14 and it arrived today so now there are no excuses. Time to start learning ARM programming and perhaps soon i might be able to turn those new found skills into a DSP IF board for homebrewers. No promises, failure is always an option 🙂

And here is the link to the course ware for those who might be interested in all this as well and want to give it a crack. http://www.state-machine.com/quickstart/

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TDA2822 Audio Amp

So I have had this pile of Ebay sitting on my desk for sometime and today I have gotten excited enough to actually start taking a look at it all and seeing how it works. I got these frequency generator chips for like a buck and after setting them up with the test circuit, i could not get them to work, it happens, now and again you get Ebay’d in the butt.

So I figured next i should test out the TDA2822 audio amps. I for 50 for 2 bucks which is a lifetimes supply. Do they work, well, yes they do and here are the results.

Here is the test circuit straight out of the PDF. As you can see parts count is low. So I put the IC on the breadboard and used just 1 1/2 for a mono amp. I also used just 2 caps, pin8 to ground, 470uf as it was already on the breadboard and the input cap on pin 1. Powered with 8v as its a handy voltage i have on my breadboard. 12v would probably be a better option to allow for a larger voltage swing.

As you can see, nothing fancy here, just the IC and 2 caps and my signal gen and oscilloscope probes doing there thing allowing the pixies to in and out and display them in the screen.

So we stick in 0.1v 600hz sinewave and see what happens.

Well, we actually hit the voltage rails and clip somewhat. 0.1v in almost 8v out, that is the voltage gain there. And when i do some da finger poken, the IC itself is cool to the touch, not warm, not hot, but about the same as ambient temperature of the room. So i am thinking Bye Bye LM386, and hello life time supply of TDA2822. And being a stereo IC, I can also bridge the left and right for even greater output. Not that I think i would need it.

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8Mhz Signal From Arduino

So you might be thinking, Bullshit, you cannot get an 8mhz pwm signal out of an arduino. But you can. Ignoring the sine like shape of the waveform below for a minute, that is the actual PWM output from an arduino uno I was using to do this. So, why is it so.

Well, all you have to do is use some code wizardry using interrupts, timers and registers in such a way that the maximum pwm frequency you can get from most microcontrollers is 50% of the clock speed. Given that the arduino usually has a clock speed of 16mhz, this gives an actual maximum pwm out of 8mhz. And while this is nice, in practice it is not all that useful as the discrete numbers of frequencies that can be derived this way is not all that useful.

The code is below, I did not write this code and sorry to whomever did, I do not have a link back to it and your name was not included in the snippet, so i cannot credit you. Enjoy.

 

 

 

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When The Image Matters

Sometimes you find out what you thought to knew about a subject is just utterly wrong. When it comes to image frequency for a long time I have believed that the Image_F = Desired_F + or – 2 * LO_F. Which is essentially true, the image can be plus or minus but I was ignoring one critical piece of information and that is the position of the Local Oscillator in respect to the desired frequency.

So there is only 1 image frequency, not 2, if the LO is below the Desired frequency then the image frequency is Image_F = Desired_F – 2 * LO_F and if the LO is above the Desired frequency then Image_F = Desired_F + 2 * LO_F. Which now means that using a 455Khz IF for AM Broadcast Receiver actually makes sense if using a high side LO to do the mixing in a superhet design.

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