Topband: Trap for 160m/80m inverted L

Bill Tippett btippett at
Fri Dec 9 11:33:03 EST 2005

N8BM wrote:
 >Is there anyone out there that has a KW80C not connected that could 1)
measure the resonant frequency with a grid dip meter and 2) measure the
length, diameter, and TPI of the coil?  With that I could calculate the
inductance and then the resonate impedance on my own.

         If you plan to run the legal limit, I would not
waste my time with the KW80C.  I had a 160/80 dipole
and went through 2 sets of those traps until I built
my own using RG8X on PVC forms.  There was a QST
article about this several years ago, and I believe
it may have included the L and C of the traps, but
it definitely included a chart with the number of
turns required for various coil form sizes.  BTW I
had the same problem with the 80m trap in a Battle
Creek Special I borrowed when first getting on the
air when I moved to NC.  W8UVZ or K1ZM can give you
the dimensions you need and you should not have the
problems the KW80C has.

                                         73,  Bill  W4ZV

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