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
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