I have built several chokes on FT240-31 cores with RG142 double silver
shield TFE coax (ok for QRO anywhere at HF) and measured them with my
VNWA 2.6. For my 160m top loaded vertical I stacked three cores and
used 12 turns for >4k ohms resistive. My results generally agree with
G3TXQ's and K9YC's charts, although I tend to use a few less turns than
G3TXQ and more ferrite per K9YC to stay further away from the self
resonance frequency. Keeping the windings tight was important. The
big type 31 "clamp ons" are also pretty handy for cables in place or
with PL259's installed.
Grant KZ1W
On 6/9/2013 6:57 PM, wb6rse1@mac.com wrote:
G3TXQ shows characteristics for common mode chokes:
http://www.karinya.net/g3txq/chokes/
Has anyone built the 17T of RG58 on an FT240-31 choke and verified the
performance?
TU - Steve WB6RSE
All good topband ops know how to put up a beverage at night.
_________________
Topband Reflector
All good topband ops know how to put up a beverage at night.
_________________
Topband Reflector
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