Nick M0NTV takes a look at the basics of what electrical impedance actually is. We consider what it does, why we would want to match it and one way we can measure it. Hope you find something helpful here. 73, Nick M0NTV
This was really useful for me and made sense. Maths is not my strong suit, I struggled and just about managed the maths in photographic theory and for paying the tax man in my training as a photographer...so this helped me a lot. Thanks, Nick.
Blimey, j notation! There's a blast from the past. As long as you never stray into calculus we can remain friends. Great video Nick, and always nice to return to first principles now and then.
Cheers Mate! You more than most people can appreciate my strained relationship with maths!!! But hey, if I can do it ... :) Must be time for a few beers down the road when you have a free evening.
What a great talk, thanks Nick! (I imagine your sermons are just as good.) "The reason I build radios is to understand how they work." Your opening remarks should be part of the credo of the hobby. Best wishes, 2E0FXZ
Loving the content! I'm so immersed in homebrew culture lately :) I'm building my own receiver at the moment that will turn into a transceiver soon :) Thanks for the content, I love the long format videos.
The beauty of the video is in the way how you explain it. I will take some of your ideas and incorporate them into a presentation I’m preparing on Smith charts for my local radio club. 73 de ON4CKM
Thank you very much indeed. I deliberately tried not to mention Smith Charts in this video but they will certainly take a starring role in the next one! All the best with your presentation and thanks again. 73, Nick
Thank you so much Tony. That's very kind of you. Funnily enough I almost pulled it in a last minute attack of self-doubt! I was concerned that it would just be too long and technical. So I'm really pleased that some people have found it helpful. Hope you are doing OK. 73, Nick
Nick, my goal as a ham is to learn about RF, and build and experiment, not to spend my day chit-chatting or chasing certificates. I want to know how to manipulate my physical electromagnetic reality of electrons and photons the same way that sailors do the wind and the water. I've been reading a book about impedance matching, and a video on the topic from you is more than welcome. You usually manage to make things easy to understand. Thank you. BTW, my NanoVNA, not any of my transceivers is my favorite piece of equipment. That sort of labels the type of ham I am.
Thank you so much John. I'm delighted you share the same curiosity and fascination with all things electromagnetic. Incidentally what is the book you have been reading on impedance matching? I'm always looking for more inspiration! Thanks again. 73, Nick
@@M0NTVHomebrewing, it's actually a much more inclusive book on all facets of radio design. But I have been studying the impedance matching section as that's what I'm weakest on, (and much of radio design is just the proper matching of several relatively simple stages together,) and I've wanted to actually grok the subject instead of simply applying formulas or rules of thumb, or exactly copying what someone else has already done. The book is, to me, a good balance between theory and practice, pretty deep for a brand new new ham with a shiny new Baofeng, but nothing like wall-to-wall calculus and field theory, either. As a self-taught electronics tech, but with 50 years of work experience and reading, it came in right at the level I'm ready to learn at for RF design and experiments. You would have no trouble at all with it. In fact, you may already have it. It's: RF Circuit Design by Christopher Bowick It's $10 to $15 US, used price on eBay. There is a second edition I found on Amazon, but I found my cheap, used copy of the first edition on eBay.
Thanks very much John. I've just managed to download a PDF version to see what it is like. It looks very interesting. Thanks for the recommendation. 73 my friend, Nick
4 месяца назад
Nice tutorial! Just a word of caution about connecting the output of an amplifier directly to the nano vna. Make _really_ sure that the input is connected to a 50 ohm termination, and that there is no DC bias on the output. Have a look of the output on a scope first maybe. The ports on the vna is quite sensitive, and easy to destroy :(
Thanks Orjan! Yes, you are right to sound a note of caution. Fortunately all my amplifiers have DC blocking caps on the input and output so that's not an issue for me. Also the only signal going into the amplifier is the S11 sweep from the NanoVNA. I wouldn't feel comfortable with an S21 unless you put a truckload of attenuation on the amplifier output. Thanks again. 73, Nick
The method you presented to measure the Output impedance is interesting. You need to be careful, the amplified noise emitted by the Output (even with terminated input) could burn the S11 port of the nanoVNA. Have you seen this method discussed somewhere or it is something you came up with? Thanks!
Hi there! All I can say is that my NanoVNA must be made of strong stuff! I would imagine that the gain of the amplifier must have to be exceptionally high and/or the device be very noisy for the internal noise to burn out Port 1 on an S11 trace with no input into the amplifier input. As I mentioned my NanoVNA is a very early model but is still going strong. I'm not sure where I got the idea from to be honest - but it seems to work. Thanks for watching and commenting. 73, Nick
I am considering building the transceiver in Eamon Skelton's book. I've been reading about RF leakage in direct conversion transceivers, which raises some questions: Is it an annoyance or a serious problem? Is there a viable solution? Should I consider a superhet instead?
Hi Gregory, I've built several direct conversion receivers but not a dc transceiver. I think the lack of filtering would get on my nerves too much. As a simple receiver the direct conversion is a great project but for a transceiver I would want the selectivity of a superhet design. Skelton's book is great and I highly recommend it. 73, Nick
Hi Nick! Great video! I am an undergrad pursuing my degree in EE. Currently, on my last semester and I enjoy building filters. What was the name of the youtuber you were referring? Thank you and keep up the post!
Hi Kevin, thanks very much. I think it was probably Alan Wolke W2AEW who has a superb RU-vid channel for anyone interested in electronics and particularly RF electronics. 73, Nick
