Your First Varactor Tuned Crystal Radio

Mike, I can only thank you for putting up such a lovely set of very informative videos about radio and using tubes and semiconductors. I hope you can do many more. Balanced modulators etc. and phase locked loops. One of the most down to earth real radio hams I have ever seen. Just wonderful and I am learning loads even though I already have a degree in electronics from Oxford. Please make more.

Without a doubt, my favorite crystal radio video. Excellent content and quality work. Thanks Mike...

Your video answers a lot of questions I had about crystal radios. Thanks

When I was a very young kid building my first crystal set I was so impressed it worked when I hooked the ground wire to a water pipe. Could not understand that the ground was a big part of it's operation. Thanks for your vids. Carl, AB1ZI

This is a nice video, great comparison between the diode types. I just used a varactor diode in a receiving only antenna system to tune it across the bands, and it works really well, thanks for the confidence boost to get me motivated.

I really admire you skill and knowledge.

If only you were nearer. I could learn so much. Your knowledge is astounding.

Very helpful thank you. I found this video just when I was wondering where I was going to find a decent source for tuning capacitors for my home projects.

I did the same nonsense, but I am proud myself as you should. Thanks for your fantastic information.

Thank you Mike. Very interesting and always appreciate your videos.

Wonderful demonstrations!

Mike, thanks for another great video and for investigating a wide range of devices and configurations. As a regulator, for accuracy a Zener has to pass significant reverse current. It seems unsurprising that, when instead it's used as a varactor with a similar applied voltage, it loads the tuned circuit. TBH I wasn't expecting the Zener to work even as well as it did.

I have not tried Varactor tuning for the BCB but I do use it for tuning my 40M DC receiver with a pair of 1N914 switching diodes in parallel and it tunes 15 KHz ( 7.029 to 7.045 ) of the portion that I normally listen to. I loved the Book Condensers used in the 1920's Crosly radios in my collection years ago 🙂

Thank you. You do things differently to all the other videos on varactors that I have seen so far. What I loved was that you put in different diodes and compared. That is brilliant teaching 👏 😀. I am getting a feel for the varactor now. Thank you so much. You are what makes the Internet a gift for everyone else. You also empower people like me. Thank you.

I ordered one of the NTE618 varactor diodes from Amazon immediately after watching your video. I received it today and incorporated it into the circuit using your ferrite rod receiver - "Spare The Rod? Spoil the Crystal Set". The varactor works very well with the ferrite rod. I am really impressed with the performance of the varactor diode. There's a big hole in the prototype where the 365 pF cap used to be. The NTE618 diode is tiny but its performance is huge. I have a lot of tests to perform. I'm going to see what range I'm getting. I have a signal generator I can use to test the range. Most of the stations come in in the upper portion of the band where the voltage on the varactor is at 1.5. volts or less. I'll do more tests and report more later.

Definitely worth a try.

Excellent video thanks from England 🇬🇧

this turned out to be a very good video

Good video, thanks as always.

Excellent! Ive seen those linear shaped capacitors before and always wondered why they were shaped that way, stunningly obvious when you point it out. PS my background is not radio, its dc or digital stuff :)