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Excellent video ! I appreciate your clear and thorough approach. This technology cannot be replaced by SDR when power is involved eg. in a transmitter. Keep up the good work !

Thanks.

My mini system jvc is out of frequency radio fm . Jvc mx-g7. What happens??

I would have liked to see the design of those two sample filters you created. Design, construction, and testing. That would make a interesting video. For instance how did you spec out the size, positioning of the internal components & how to make any adjustments (presuming its possible with the construction method used.

"I signed up to a degree in electronic engineering, NOT plumbing!"

Can we see one of those nifty copper boxes on a VNA? 🙂

Thanks for explaining Cavity filters.. Very black magic 😛

Analog is king. 🙂

great video many thanks... talking about amateur radio "abuse" of these things I have heard of aluminium beer kegs successfully being used as the conductive "cavity" for a VHF filter but the best one was a April fools joke about a 30' shipping container for a 7MHz (40 metre) cavity filter.

Do a search for the "Kellermann Balun". It might be of interest to you and others, possibly try to simulate it and figure out how it works, the theory behind it. I contacted a few people on the subject, not much was given out. I'm a retired RF engineer, and also a Radio Amateur for 50 years. If I get the time I will also build one to test. Mind you that it is a 1:1 Balun. From what I can understand, it will handle plenty of power, depending on the size of the coax used, eg: rg142 or rg393. Should be a perfect Balun for a Balanced Tuner, on the input side of course, 50 ohms unbalanced in , output balanced.

I have been waiting for a clear and concise video on cavity filters forever! Thank you so much!!!

Can’t wait for the practical measurements! 👍

Super interesting as always. Question: the 50 ohm source impedance in the models should be in series no? Or what is the effect of having this resistor in parallel with the voltage source?

Great topic 👍

How can you choose the right Beta, If there is no problem everybody would choose 800, What is the method to choose "Beta"

Any chance for FEM of these filters? Like, what's an optimal coupling loop shape / position? Some coupling loops use flat wire instead of round. Why?

Good explanation! Thanks for sharing! 👍

What is the use of these narrow band filters? For an application such as a radio station you need a 100khz bandwidth, which this narrow band filter doesn't seem to cover, maybe it covers a 10th of that at best. Sorry I think I know why, it's so that small band signals don't mess with the modulation of bigger band signals

Excellent and elegant as always. This exemplifies the artiness of electronics!

having seen this some time ago in one or some of Curious Marc's vids, this is finally building the missing link to this dark art of trolling the rest of electronics!

The dark magic of electronics

What?! How come I find out you're Romanian only now? You should have seen the look of shock on my face when you pulled out that electronics book... Te salut!

6:40 Not quite sure why does coupling the two inductors give better attenuation for common mode.

Hi. I had very accurate working model of vacuum tube 12AX7. After refreshing my PC new installation (with new blue buttons tool bar) doesn’t run old saved files with tubes. Do you know what is the issue?

in many class C amplifier the Capacitor which is parallel with the coil on the collector is omitted. Can you explain why that is?

I went ahead and implemented these two features as components (source-like constraints) that can be placed in LTspice. The "Iconst" current constraint can be placed in series with a source, whereas the "Vconst" voltage constraint can be placed in parallel with a source. Example test-jigs included in the zip Link to the library: drive.google.com/file/d/1I3VxgBCDz8ntf56d5Q9Zr3E13vShVpg9/view?usp=sharing

Thank you sir. Great simple demonstration.

You have the best crystal method.

one of the bests electronics channel! thanks!

What is simulation software used for circuit design?

Interesting videos thank you. Everyone love Software defined radio's

The crystal model used is called the Butterworth Van Dyke (BVD) model. The model can be extended by adding multiple RLC circuits along with a single parallel capacitor to model the primary and secondary resonant and anti-resonant frequencies. For sonar usage, widening the band between the resonant and anti-resonant frequencies by addition of series and parallel inductance is an underutilized method for achieving better performance...

I don’t know what other channel that I watch every new video start to finish as soon as it drops. Another fantastic video! I was part way through building a superhet transceiver by building each module, and the crystal filter was the most fun to build.

Feszzzzzzzzzz.....

Hi there for the demonstration of the filters with the sdr software with rtlsdr hardware there are horizontal lines in the waterfall which oszilate a bit over time. If i am not mistaking i would think this could be the automatic gain control adjusting amplification making the comparism wrong. What do you think?

You forgot about Monolithic Crystal Filters (MCF) :-)

Is order of the filter the only reason why there were some extra spikes in the filter response ? Or is it also because of the imperfections in the crystal ? Also how can we get rid of those spikey responses ? Excellent video though.

Why did the first filter not make much of a difference in the SDR graph? Based on the plot of the filter characteristics I expected a much better result.

Consider changing your greetings at the beginning.

Thank you for the video, it was really helpful. Can I know the data sheet of the second filter of 10.7MHz ?

Thanks a lot. Would be very appreciated analyzing also N-path filters which are also characterized by very narrow-band frequency response.

Thank you.

I really like the AADE Designer tool. I have one of his AADE LCR meter. Great demonstration! 👌

At 4:48 you introduced a diode across SW2 to ensure current is always flowing through the inductor. How does the diode achieve this? Its anode is at ground so the only way for it to conduct is if Vs2 < -0.6V rigbt? Why is that node swinging below ground when it wasn't before (the only change is that you introduced the delay). Is it that with the delay, the left hand side of the inductor would be floating for a short period of time, changing its voltage to try and keep current flowing, and the diode now allows current to flow from ground, and into the inductor?

Excellent video. Still one querry, in Frequency modulation , class C amplifier is used . Whether full sinusoildal Wave is the output of Class C amplifier or a limited angle ( less < 2 pi ) is used ? Thanks

Amazing as always! Thank you

In your first computer simulation, you have a 50 ohm source feeding a 100 ohm resistor in series with a 100 ohm resistor in parallel with a 1 ohm/1uF to ground. Where did you come up with this model for the simulation? Where's the necessary inductance? Is it already cancelled out? How do you reconcile this model with the antenna circuit definition of R+jX? How do you unbalance a resistor in series with an inductor and capacitor? You are familiar with R+jX, right?

Very good!

thank you

thank you