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Book recommendation
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Please excuse this if somewhat off-topic here.? I would like to learn about the operation of the QMX
?family of kits over and above the terse explanations given in the manuals. I would be grateful for
advice on what to read, either in book or paper form. My background in electronics is rather poor,
but would not be intimidated by? maths. Thank you for any pointers. |
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Fernando,
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The QMX includes techniques first developed for the QCX and QDX.
There sections in each assembly and/or operations manual that delve into how it works.
They are not always terse.
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The Wiki of this forum has lots of good information too.
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Do a web search for "hans summers fdim" to find presentations Hans has given.
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The above is all QRP-Labs specific
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For basic knowledge on how radios work, I can think of nothing better than Experimental Methods in RF Design (EMRFD).
It was written over 20 years ago and is now out of print, getting difficult to find used.
Personally, I think it is a major sin for the ARRL to not keep it available, at least as an ebook.
A thorough search of the web might find ways to obtain it.
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The Radio Amateur's Handbook by the ARRL has lots of good theory and practical design, well worth owning.
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RF Design Basics by the RSGB looks promising though I have never read it.
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Many amateurs limp by without a thorough understanding of complex impedance.
As the name implies, this involves values of the form? ?a+jb? ?in the complex plane.
In electronics we use j for sqrt(-1) since I so so often used for current.
I can't think of a book I'd recommend though I'm sure they are out there.
What I can recommend is obtaining a nanoVNA, it is a very useful tool for the radio amateur
and is all about measuring complex impedances.
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Digital Signal Processing is where you will find a good deal of math to puzzle over,
it is the foundation to how the software in the QMX works (and the hardware of the QCX).
An excellent introduction to this is this free book on the web offered by analog.com:
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Also free from analog.com is the excellent LTSpice simulator, it allows you to model working circuits on your computer.
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Perhaps others could recommend other sources of information.
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Jerry, KE7ER
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On Fri, Jan 24, 2025 at 01:25 PM, Fernando TUSELL wrote:
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On Sat, Jan 25, 2025 at 07:02 AM, Jerry Gaffke wrote:
This book looks readily available as a pdf online.?
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I must confess I'm one of those that limp by though. I'd love to understand more of the technical aspect but sadly my spare time is limited and I have other hobbies to squeeze in as well as getting on air and operating.?
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I have successfully built the QMX and QMX+ though so am happy enough with that success :) |
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On 25/01/2025 07:14, Danny Bower via groups.io wrote:
This book looks readily available as a pdf online.Yes, the free and easy download was about 40-50th link in a Google search. It reminds me of how much I've touched on in ~70 years in the hobby and I'm still limping... 73 Alan G4ZFQ |
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Thank you, all. Jeff, EMRFD looks close to what I need. Seems it is out of print, but already found a PDF.
The book by analog.com is also promising.
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Hans Summer's explanations are too terse for me indeed and assume a level of expertise higher than I have,
which is why I asked for other material. I cannot hope to have a thorough understanding of everything I use, but to the extent possible I try not to use things as black boxes.
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Thank you again.
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ft. EA2BEE |
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