[TowerTalk] EFHW core

[jimlux]

On 9/22/20 10:04 AM, Jim Brown wrote:
> On 9/21/2020 5:11 PM, Ignacy Misztal wrote:
>> It s hard to be smart here without tons of experimentation.
> 
> Huh? How about studying the fundamentals? The ARRL Handbook and ARRL 
> Antenna Book are great places to do that. NEC modeling is a great 
> learning tool for antennas, and SimSmith is great for studying 
> transmission lines and matching networks. There are several tutorials on 
> my website that cover ferrites and common mode chokes. Jerry Sevick 
> published a lot of great work on transformers using ferrite cores.
> 
> 73, Jim K9YC
> 

And these days, one can buy a nice little VNA (NanoVNA) that works great 
at HF for $50 - just the thing for checking the calculations.

Of course, then you'll wind up learning more than you want to know about 
"fixturing" for testing your transformers and chokes.

I will say that magnetics design is very much a "calculate, then try" 
sort of thing. There's a lot of things (like parasitic C) that are hard 
to model with simple tools.