TopBand: Coaxial Cable Traps

[George & Marijke Guerin]

Hi Gang:

A early in the 1980's some of pre-reflector topbanders had a discussion
about traps made out of coaxial cable vs. traps made out of descrete
components for multi-band inverted L antennas.  This was prompted by the
heating in the original RG-58 coaxial traps W0CD made for the first two
Battle Creek Special antennas.

Our second step was to try the marine grade RG-8X, which was somewhat
better, but still heated more than we wanted.  After a trip to one of
the Pacific islands by a group led by W0RLX and K9AJ, where the 80 meter
trap heated enough to bend by the pull of the top loading wire on a CPVC
form, we went to descrete components. 

At the time we thought about RG-58 insulated with Teflon , but were
warned off by a sales representative from a wire company.  He said the
center conductor of the coaxial cable, wound over a 1.9 or 2.4 inch
diameter form would eventually drift in the insulation, as the Teflon
would flow slightly from winding and from each inductive heating from a
night's operation by a DX-pedition.  Was this fellow knowledgeble, or
just overly conservative?  I never experimeted with the Teflon coax, so
there is no experience in Battle Creek.

Your comments please, either direct or on the reflector.  (Bill's
choice)  

George,  K8GG

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