Wednesday, August 29, 2012

Toroids and an Audio Amp for the RockMite

I’m still awaiting the arrival of the 30 meter RockMite, but its early days yet and normally takes around a week to ten days to arrive.
I plan to add all the mods I’ve done for the 40 and 20 but also have a play at changing L1 for a toroid. I’ve taken the details off the RockMite forum and its look pretty easy to do, but as I’ve never done any windings before I’m a little nervous; there are many claims from hams that winding a toroid can be a painful experience!
Well I gave it a quick go last night and in all honesty I didn’t seem to have a problem, I had to do 7 bifilar turns on a T37 core, it was just a matter of making sure that the enamel copper wire didn’t twist and obviously had the correct number of turns and the connections were correctly linked together.
You’ll notice I describe all this in a distinctively non-technical manner. I must admit I’m not really a technical person and my electrical capabilities are fairly basic, but I do believe that by reading up and asking questions you can learn so much, this by the way does not just apply to electronics but everything. My motto is never be afraid to ask even if you think its the most dumb question, someone will know the answer!
My electronic knowledge is as I said basic, but I passed the amateur radio exams and I understand enough to get by. I still get confused by schematics, I know all the components but I make the common mistake of not separating the drawing from how it will actually be laid out on the circuit board and also I get confused with ground and wonder why the ground connections are not shown connecting to “something”.
But I’ll persevere and no doubt eventually in a few years’ time when I read back on this post I will wonder what all the fuss was! I look at all these RockMite projects as a bit of fun but also a big learning curve. In the near future there is no doubt I will buy a larger transceiver project, I don’t want to purchase an expensive kit radio and then halfway through find out I’m stuck, I want to be able to build it and be confident in understanding how it works.
The other project I’m attempting is a simple audio amp using an LM 386 chip. I found a You Tube instructional video and decided to give it a go. My first attempt ended in failure because the chip I was using (pinched out of an old Lake morse oscillator) had failed and when I had completed all the wiring and gave it a test I could hear sounds but they were not amplified.
I rechecked the entire wiring etc. and came to the conclusion that the chip was definitely faulty. So at the moment I am awaiting another chip which hopefully will arrive in the next day or two.
Unfortunately I never got round to servicing the cobweb, bad weather and other jobs got in the way, but I have some holiday coming up and I will finally get round to giving it a good clean.

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