[ADXA] Updated K9YC common-mode choke PDF now available

[w5zn at w5zn.org]

In my ADXA presentations you have all heard me reference papers that my 
buddy Jim, K9YC has published regarding the proper use of toroids, and 
the correct toroids to use, in elimination RFI and noise sources in your 
station. You know I am a solid believer in his work and have implemented 
his past recommendations in my station with significantly improved 
results.

Jim just recently published an updated paper. Below is an email from Jim 
that includes the link to the latest revision. Don't get discouraged if 
you read this paper and don't understand it.....you're not alone. To be 
honest, I usually have to read heavy technical papers a couple of times 
(or more) before it sinks in. If you hit a point you do not understand, 
STOP! Go back and pickup where things started getting fuzzy and take is 
slow, visualizing what is being presented.

As an FYI, if you are not familiar with RG400, it is double shielded, 
silver tinned teflon MilSpec and aircraft rated version of RG58. Over a 
year ago I began replacing everything in my shack and station that was 
RG58 with RG400. For those of you who have been to my station you know 
that was a big chore but I replaced everything RG58 that was carrying an 
RF signal regardless of how insignificant it may have been. RG400 is 
expensive but to be honest QUALITY is not spelled "CHEAP"! Yes, there 
was an improvement at W5ZN.

Sources and prices of RG400 vary. If you have an interest in RG400 drop 
me a note off line and I can supply my source for the cable as well as 
the source for any PL259, N or BNC connectors you may need.

73 Joel W5ZN



 From: Jim Brown <jim at audiosystemsgroup.com>
Date: Mon, Jan 21, 2019, 11:36 PM
Subject: Inverted L improvements - Part 3 (now with data)

After nearly a year of work, I published a new "cookbook" last month.
For reasons that are detailed in the accompanying text, I no longer
recommend coax wound through multiple cores.

The short answer for "why not?" is that it's simply not practical to 
wind
chokes that way and get anything close to the same result every time --
turns must go through the core in the same order, a scrambled turn 
cancels
a turn, turn diameter matters a lot, and so on.

The new cookbook uses RG400, 12-2 Teflon/silver pairs, or 12/2 THHN or 
NM
pairs, all tightly wound around a single core.  There are 
recommendations
for chokes in series to increase power handling. There is also data for 
the
new 4-in o.d. supersized toroids, which are great for 160M.

k9yc.com/2018Cookbook.pdf

73, Jim K9YC