<This new tool may be of interest to at least a few TowerTalk folks.
<Currently being discussed, with some sample illustrations, here:
<
https://forums.qrz.com/index.php?threads/new-tool-toroidal-ferrite-core-inductor-<calculator.768222/
<https://forums.qrz.com/index.php?threads/new-tool-toroidal-ferrite-core-inductor-calculator.768222/>
<Or you can download the full 13 page Help pdf and the Excel workbook
<from the link at the bottom of this page:
<
https://sites.google.com/view/sp3l-hf-antennas/home-page/miscellaneous/toroidal-<ferrite-core-inductor-calculator
<https://sites.google.com/view/sp3l-hf-antennas/home-page/miscellaneous/toroidal-ferrite-core-inductor-calculator>
<Note that the workbook requires Excel 2007 or newer. It cannot be
<used with other spreadsheet programs such as OpenOffice and
<OfficeLibre nor with Excel 2003 and older.
<Dan, AC6LA
I only have Openoffice, it opens ok, and I can toggle through all the tabs,
BUT it comes up as....read only mode.
I noticed it will only handle a maximum of 3 x cores, why is that ? I
use 5 x cores, type 31, 2.4 inch OD on both my 160 and also 80 and also 40m
CM chokes.
It will only handle a maximum of a 2.4 inch OD type 31 core. K9YCs
latest designs all use the much larger, I think, 4 inch OD cores.
As per number of turns, is this for wire, or coax, or can be used for
either ? If coax used, what type of coax ? I used RG-303 and RG-400
on the smaller CM chokes....and RG-393 on the bigger CM chokes.
Looking at the various attributes of a type 31 2.4 inch OD toroid, by
both fair rite..and also amidon, I am not seeing any difference in
properties between the 2 x manufacturers.
On a side note, N3RR, Bill Hider, a few yrs ago, bought 700 (seven
hundred) of the type 31, 2.4 inch OD cores...from I think, Fair
rite..... and the tolerance between all of em was strewn all over the
map, like + or - 20+ %. Bill came up with a simple 1 turn test to
evaluate,and then grade them into various groups. Some time in the past,
apparently Fair rite moved their production facilities to CHINA, and
after that, the +/- tolerances went all to hell.
So while the software may well get you close, one would still have to
test the final assy...with a vna or my method below.
For CM chokes, I took the easy way out...and just measured the actual CM
current with a clamp on RF ammeter on the coax. I measured in several
places on the coax. I marked the various measurement spots with painters
green tape, like 2 x wraps, with a space in between..where the clamp on RF
ammeter goes. With power level fixed..and on a specific measuring freq,
one CM choke assy can be replaced with a different designed CM
choke....and any improvement of degradation is easily noted. Typ what
happens is ALL the measurements will rise....or fall an equal
percentage, when a CM choke assy is swapped to a different designed CM
choke.
Jim VE7RF
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