11 - Designing an LC Filter

[@TrystansWorkbench]

Nick - a superb video, incredibly well explained. Looking forward to Part 2 and Part 3 now! It's good that you showed online calculators too, as it's accessible to all of us, and as you say, "Why reinvent the wheel?". Trystan

[@M0NTVHomebrewing]

Thanks Trystan! Hope you're doing OK. 73

[@johnwest7993]

I love winding toroids, building and tuning filters, modifying and upgrading gear, etc.

[@M0NTVHomebrewing]

Hi John, it is fascinating how you can do so many different things with inductors and capacitors! 73, Nick

[@BobMellor1954]

Hi Nick, thanks for this, I'm just starting in the hobby and find this kind of information both interesting and useful.

[@M0NTVHomebrewing]

Hi Bob, thanks for watching and getting in touch. I'm glad you found it helpful. All the very best to you. It's a fascinating hobby with countless rabbit holes to explore! Enjoy! 73 M0NTV

[@cbnation1]

Great video. One thing I find little to no info on is how to select components depending on the power it must be able to handle. I know the websites you mention, but how to select the right toroids and capacitors for 5W, 100W or 1.5KW? And what wire thickness to use for the different power levels?

[@M0NTVHomebrewing]

Thanks Cedric. You might find this article by the late great George Dobbs helpful: pdf4pro.com/amp/view/a-short-guide-to-harmonic-filter-for-qrp-transmitter-18ac31.html Essentially, as you'd expect you'll need larger cores and perhaps even multiple cores to handle greater power levels. Wire thickness is a trade off between using the thickest wire you can to get the required number of turns to cover 3/4 or 4/5 of the toroid. Check out other people's designs and experiment! Personally I've never built an LC filter to handle more than 100W (I'm more of a QRP guy) but clearly it can be done. Have fun!

[@Steve-GM0HUU]

I also usually find my type 2 or type 6 toroids have slightly higher measured inductance than the calculators, tables or formula suggests.

[@M0NTVHomebrewing]

Me too Steve! 73 Nick

[@acestudioscouk-Ace-G0ACE]

Thanks for this, for newbies like me it takes the dread out of toroids and filters.

[@californiakayaker]

reminds me of ND6T's work !

[@M0NTVHomebrewing]

I've not come across him before but I've just looked him up now! Very good. 73

[@berth2647]

I like your videos ,,

[@amirb715]

yes, nice. keep doing what you are doing. :-)

[@M0NTVHomebrewing]

@@amirb715 Thank you Amir!

[@M0NTVHomebrewing]

Thank you Bert!

[@louisbanaszak3125]

no video number 3 ie testing

[@M0NTVHomebrewing]

Hopefully later this week.

[@elwood.downey]

Nice, but I thought you wanted a high pass...

[@elwood.downey]

Oops -- was reading S11 and S12 swapped.