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Thanks so much Sir for your detail explanation. I learned a lot for this and the previous videos.

Hi, over the past 12 months, I reckon I've watched every transistor video on RUclips, trying to get the "penny to drop". With your detailed and very easy explanations and practical examples, I now get it. What a great video. It certainly wasn't too long as this interesting video seemed to be over in minutes. I was glued to the edge of my seat, as I was able to finally understand, put it all together and follow along with your examples with the transistor and resistor theory. Now for Part 2. Thank you for putting in so much time to put this video together, with your patience and easy to understand examples, you'd make a great teacher or instructor. I've also stumbled across another great channel to subscribe to. Cheers from Hobart, Tasmania, Australia. Darren

33:30 i don't get it why 10times ib, when find the R2

It takes long time to explain a smaal item

Thank you for the video. It would be useful to note the toroid mix values used in the band pass filter. From the pictures it looks like mixture 6 (yellow) toroids were used, which can have a relatively high Q factor compared to ferrite core mixes like 43. The SWR curve of the bandpass filter may be a bit less steep with a more broadband toroid. Nonetheless, the diplexer seems like the right solution. Thanks again for the interesting video.

What current value do you use when matching diodes?

And.... Finally caught up! Excellent little receiver there Nick. I have a little something for you next time I see you. Have a great Christmas and new year, and to S. See you on the other side.

Mate, that was heavy for a Sunday morning. Nicely done though!

I'm playing catch-up today mate, this is the second video, I'll save the next for tomorrow. Excellent explanation of the biasing theory, thanks for that. One note, clipping is a danger for the speakers - not at the power we're talking about here but when you move up in power it becomes so. When the output clips it becomes a DC signal, the voice coils start dissipating a lot more power than they're designed for and they release that magic smoke. There's an old saying - anything can be a smoke machine if you try hard enough.....

Hi Nick. How did you come up with the 83Ohm value to simulate the relays?

The schematic for the tia-agc shows an inductor, L1, and there is a place for it on the pcb, next to Q4,. But nowhere can I locate a specification for this inductor. The schematic listsit as "L". What value did you use?

👍Thank you sir.

Appreciate the fact that you went through all the math. The only thing I didn't get really well was why use those condensers. I'm not an electronics engineer, just a computer engineer trying to learn a bit of electronics so I can make some DYI guitar pedals. Just came accross this and thought it was interesting, you can basically make a guitar power amp with this basic scheme.

Was wondering if you can use a much larger gauge wire and improve reception? Thank you for the video.

Thank you, very good and simple explanation! 👏

Interessante essa forma de controlar o AGC, eu já tinha visto uma técnica parecida em uma revista de eletrônica antiga, só que o transistor ficava conectado entre souce e terra(FET no pré-amp. de RF) e emissor e terra no amplificador de FI.

جيد جدا

Great effort! Traditionally, padding was in series with the tuning capacitor; trimming was in parallel with the tuning capacitor. This method was traditionally called Homodyne detection receiver. I remember reading about it in Wireless World magazine in the70s.

Where did u buy ur variable capacitor? I realy like the way it looks including the button on it

Dual gate MOSFET makes for great AGC too.

I've always been fascinated by the possibilities a direct conversion receiver project offers. But no tuning capacitor local oscillator. I want my oscillator to be a digital synchronous sort - gone would be the tedium of moving from signal to signal with a less than precision tuning mechanism. Good fun this stuff!

Thank you for sharing we appreciate it very much

Nick, I love the analog approach, and your use of a VFO...I am very much in mind to build one very much like yours...I can't believe all the advice and controversy that came from this one video! You have a careful and thoughtful approach to design, and i just love it! Keep it coming! Merry Christmas, and Happy New!!

On the three Softrock kits I've built I've had to use an LNA in the front as they always seem to be a little less sensitive than commercial receivers. The LNA design was from the R2Pro LNA by KK7B that I built dead-bug style and yielded around 12 dB gain. Thanks for sharing your work Nick - always a pleasure - 73

It is advise to do some low pass filter before the SSM2167. Otherwise if there is some loud above 3 KHz, the chip could start compressing while the speech could be quit and must not compressed.

Nice. I am a retired pure mathematician that took up electronics as a hobby similar to taking up cooking as a hobby over a decade ago as an outgrowth of using partial differential equations to model simple antennas in order to see mathematics modeling a real world phenomenon. I don't aim for my hobbies to lead to being a 5 star chef nor EE; rather, my aim is much more restricted. None the less, lately I have an interest in building one of each style of receiver up to & including superheterodyne. I am now past the stage of regenerative type receivers and looking forward to a direct conversion receiver. Not having previously built a direct conversion receiver I find sometimes schematic representation on a great design can be a bit cryptic to a new builder by the draftsperson having essentially used a means of representation in the schematic that anyone having previously built the project would immediately recognize, but not necessarily a first time builder. You gave me the notion that the receiver your assembling or a similar receiver is the one for me to start with because in a AM radio club video recently published on RUclips you suggested the instructions and plans for the direct receiver you were demonstrating having a gluestick based variable inductor was really excellent and very detailed. If you could give me a link to the plans & schematic I am implying please do, I'd really appreciate it. It will be a fabulous winter indoor project now that snow has hit my neighborhood in the Catskills. Thanks in advance Mike Boyer

I just used a two-stage version of the hybrid cascode as my IF amplifier in the new transceiver that I'm designing, and it is indeed an excellent RF amplifier with a very large control range. Worked perfectly for the simple AGC system that I implemented. 73 DE NT7S

Nick--It's always a pleasure to see something from MDRF in the wild, and thanks for the plug. Using the TIA-AGC as a variable-gain pre-amp is a great idea, especially with a front-panel gain control as you've done. I've been doing some experiments using low-noise transistors like the BF106 in place of the 2N3904 in the TIA amps. This might have some value in a pre-mixer RF amp since any noise introduced by the amp itself will be amplified in subsequent stages. Whether or not there'd be any noticeable benefit is hard to say, but there's always the placebo effect to come to the rescue if not. --Todd K7TFC

Fun bit of home brew there Nick. Have a great Christmas and looking forward to your 2025 vids!

Amazing project, I am working in the same build. Can you please show more about the Audio amplifier ( video or link ) ? Thanks

Gee, the only thing missing here would be lasers linking all the components together instead of cables, then you could really spread it out all over your shack. 😀 A long time ago I spent a whole day in the Exploratorium in San Francisco which is a science/tech museum set up by scientists from Lawrence Livermore Laboratories using surplus equipment from the labs. This was when lasers were still new and they were using a visible red laser beam to transmit the audio from a broadcast radio up the wall to a mirror, across the ceiling to another mirror and then down the wall to a detector/amplifier/speaker. They encouraged people to put their hand in the beam as a way to verify that the sound was actually being transmitted by light. I thought that was so cool.

Hi Nick, nice build! The reason for tuning 160, 80 and 40 from high-to-low frequency is because it's easier to approach a LSB signal that way - the signal is heard at high pitch, then gradually lowers to normal before cutting off after zero beat with the suppression of the upper side band. Of course, with a DC receiver it makes little difference, as you are not sideband-specific - the signal goes through zero beat and then comes out garbled on the other side. Padding tuning capacitors (for those who don't know) is best initiated with a simple LC frequency spreadsheet where you can substitute series and parallel capacitance values until you get the range you want. Season's Greetings from M1GWZ (Echelford ARS).

Great stuff Nick, I really like the modular approach here. It makes it easier for this beginner to understand and build. A busy time of year for you and I wish you and yours season's greetings.

Well done Nick, thoroughly enjoyed this series (as I do most of your builds) All the best for Christmas and the New year from me as well. Andy G0POY

Great design. Thanks so much for your content this year, I’ve learned so much! Merry Christmas to you and your family.

Nick: Some comments from the SolderSmoke blog: First, let me say FB Nick. It is nice to see you making use of the AGC amp designed by Wes and Bob, using the board from Todd's Mostly DIY RF, using a mix of homebrew pads and Me-Squares from Rex, and finally the Franklin Oscillator that we spent so much time talking about on SolderSmoke. But here are some comments: -- I still don't think you need that RF amplifier in front of the mixer. And I suspect you would be better off without it. We did not use one in our high school 40 meter project, and never missed it. In fact, on one version of the high school receiver I even put in a simple 10k pot as an attenuator (no RF amp). Even up on 20 meters, I do not have an RF amplifier ahead of the diode ring mixer on either of the Mythbuster rigs I have built. Nick, maybe experiment a bit more and try the receiver just going from the BP filter into the mixer and see what happens. Note that Wes W7ZOI DID NOT have an REF amp ahead of the diode ring mixer in his original 1968 40 meter Direct Conversion receiver (the one that launched the solid-state DC recevier revolution). -- The Franklin oscillator is an interesting, but complicated circuit. The gimmick is, well, gimmicky. Here is the thing: You can achieve similar levels of stability using simple conventional, single transistor oscillators. We dispensed with the variable capacitors, and used PTO--style variable inductors. They worked fine. This Franklin oscillator still does seem to drift a bit, right? I would ground the board to the inside of the metal box. I would also try putting all the stages on a single ground plane. This might help. 73 Bill

Nice

Seeing it all boxed up looking so well done is inspirational. Maybe I’ll actually put something in a proper case some day 😂

Glad I’m not the only one whose radios end up sprawled across all creation. 😂 Great video!

Bravo Nick. What a great radio receiver. I do like you variable RF amp/attenuator. Merry Christmas Greg

The heat sink will work much better if you but it vertical and a few cm above the table so more are can flow to the heat sink.

Brilliant work fine business old man!

The world's best teacher thanks sir

Could try vxo using ceramic resonator☕

👍Thank you sir.

👍Thank you sir.

Are those electrolytic caps? If so, which side is the -?

Do you have any of your videos where you show how you make the holes in the little tins you are using as shielding? They look so much better than mine. Fantastic video! I'm testing an ADE-1 and not getting the rejection I expected, so went looking for examples as a sanity check. Think I may have busted mine somehow.

Good stuff. Thank you, Nick. It's much easier than I remember from my school days. As it's impossible that my IQ has magically increased over the last 25 years, it seems, that you can explain things much better.

Excellent video . Very clearly explained and great presentation as were Parts1 and the Intro. Regards, Kieron.