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Wayne Rogers

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  1. A Nilma radio is some radio designed by some Indian bloke called Ashhar Farhan in the year 2014 I believe, It was something I got interested in reading when I found the site years ago, The radio is meant to cover the whole HF range from 80 meters to 10 meters so I read, I have not got there yet in its construction plus the fact if and when I do, a licence would be required to use it if it worked. Something I would think about if I ever get there. The radio it self is controlled by a Arduino Micro controller. At the time of finding the site I was newly into learning a bit about those micro controllers. In any case the radio is meant to cover AM and Side Band and also have Morse Code. There are probably a couple of other tweeks it has too, but I am not fully up on Amateur Radio. For me it was just a challenge to build it and learn along the way basically on the circuitry side of how it works. As for the T37-6 Cores I do have a couple of them yes but I would have to order more if I was going to fit them into the board. There filters are used to filter what comes on and goes out of the circuit on the antenna line. So I read they are meant to be from 1 to 15 MHz is one and from 15 to 30 MHz the other, however I did put those numbers into an online calculator and didn't come up with those figures. But for now for me it is a suck it and see thing, I have also added a piece into the board between the last trifilar transformer as to where I can add a pair of pins, these can be jumped over or used to add a amplifier into that point. Mainly because the filter come directly off the mixer through a relay. There is a small amplifier I found designed by another bloke called Harry some wheres up around Canada I think which might work well if needed in there. Anyways I will leave you with the schematic of this particular radio and if you would like more of what I have on it I would be happy to send it to you.
  2. Hello, - I found a schematic some time ago and decided to give it a go, this schematic is called a Nilma Radio; now this is my second attempt at it. The first time I damaged the board tracks with excessive heat, by using an incorrect soldering iron, and I didn’t at the time feel like printing out and drilling another board so I dumped it. However some years later for some reason I have decided to have another go at it. This is a Hobby of mine and I need something to keep my interested in something. Now this is what I wonder, this is what I presume to be a Butterworth Tee Filter, for the bottom and top side of the HF range. The marked top line I presume has a cut off is at around 13 MHz and the bottom line at 28 MHz. Now I believe that I read that a low pass filter allows through everything under its cut off mark and grounds everything over it. So I am wondering if I will get away with using T37-2 cores for winding all of the inductors, being that are meant to be rated between 2 and 30 MHz. Or should I use them only for the top line and use T37-6 cores for the bottom line. T37-6 cores are meant to be good from 10 MHz to 50 MHz. I only ask because, in my junk box; amongst the other parts I was going to use in my last attempt, there were T37-6 yellow cores wound along with T37-2 red cores. So there might have been a reason back then but I can’t remember what it was. So is there anyone out there who can give me a hint to point me in the right direction of what I should use and explanation of why. I look forward to some advice thank you Wayne Rogers
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