Cavity Filter Basics
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- เผยแพร่เมื่อ 28 มิ.ย. 2024
- #227 In this video I look at another constructive type of filters that moves from the world of lumped elements to the world of distributed elements, what I'm referring to is cavity filters. I look at some of the basic operating principles as well as some constructive types and next time I will be performing some measurements on a set of practical devices.
Filter series:
Ep1 - Intro : • Intro to Filters
Ep2 - Passive RC Filters: • Passive RC Filters
Ep3 - Active RC Filters: • Active RC-filter Basics
Ep4 - More Active RC Filters: • MORE Active RC Filters
Ep5 - Introduction to LC Filters: • Introduction to LC Fil...
Ep6 - LC filter limitations: • Limitations of LC Filters
Ep7 - Piezo-Electric Filters
Ep8 - Crystal Filter Measurements and Design
Ep9 - Cavity filter Basics
Further reading:
w6nbc.com/articles/duplexer.pdf
lea.hamradio.si/~s53mv/cavity...
k5tra.net/tech%20library/filt...
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The dark magic of electronics
Rather the CURSED! area of the Dark Magic Electronics XD
Can’t wait for the practical measurements! 👍
Excellent and elegant as always. This exemplifies the artiness of electronics!
I have been waiting for a clear and concise video on cavity filters forever! Thank you so much!!!
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!
"I signed up to a degree in electronic engineering, NOT plumbing!"
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 !
Good explanation! Thanks for sharing! 👍
Great topic 👍
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.
I bet a shipping container wouldn't be big enough for 7mhz. 14mhz though 🤔
@@Dazzwidd standard length 40 & 45 foot shipping containers should easily contain a 33 foot 7MHz quarter wave resonator.. but I do agree that finding a "dunk tank" big enough to silver plate it might prove a little difficult 🤪.... I just don't know how I'm going to find a suitable filter for my stacked & bayed rotatable rhombic antenna farm.
Analog is king. 🙂
thank you, beyond my brain to absorb all of it ... right now. but gets me thinking. -
Thanks for explaining Cavity filters.. Very black magic 😛
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.
Thanks.
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?
Can we see one of those nifty copper boxes on a VNA? 🙂
Of course! I test all the filters I've built in the next episode.
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?
When modeling a voltage source, this is comprised of an ideal voltage source with a series resistor; when modeling a current source, its comprised of a ideal current source with a parallel resistor. If you add the resistor in parallel with an ideal voltage source it will have no effect (same for a resistor in series with the current source); from the "outside", an ideal voltage source, or an ideal voltage source with a parallel resistor behave in exactly the same way.
@@FesZElectronics Yes, yes! But at 5:30 you are using voltage sources. Therefore my comment . Thanks for this quick answer, and for your excellent videos!
With voltage sources, if you right click on them directly, or going to "advanced", you have the option of defining the parasitics - series resistance and parallel capacitance; in the simulation, you can see under the "AC 1" parameter definition, the text "Rser=50" which is part of the voltage source definition -so the 50ohm series resistance is included into the voltage source, it does not have to be a dedicated external resistance.
@@FesZElectronics Oh I see. So the external resistor is just an adapted load resistor? this makes sense.
gibberish. Sounds like a chipmonk