[TowerTalk] measuring impedances with a VNA

[Wes]

I was going to recommend anything written by Kurt Poulsen about the VNWA.  He is 
to it what Rudy Severns is to vertical antennas.

Wes  N7WS

On 7/30/2019 7:24 PM, Grant Saviers wrote:
> I think K9YC has a lot to say about measuring in his HF choke guidance. Great 
> work!
>
> If I understand the question correctly here is what I found.
>
> My interest is expanding into VHF/UHF and I began a search for literature re 
> chokes for yagis 6m > 70cm.  Not much turned up with googling the topic, but I 
> did find an excellent set of articles about how to measure beads & clamp ons 
> above HF to 1GHz.  The short version - it's HARD.  The good news, my marvelous 
> VNWA can do a great job if the issues are understood and the test fixtures 
> built.  However, making ferrite, from experience in a prior life making core 
> memories, is more art than science and properties are highly variable as Jim 
> noted in his test plan.
>
> So, for some great insight IMO re the issues in general about measuring 
> ferrite chokes see the 3 articles at
> http://www.reeve.com/Documents/Articles%20Papers/Ferrite%20Beads/
>
> I found the answers I needed, but will return to these papers for more 
> enlightenment.
>
> Grant KZ1W