Topband: BCS Clone 80m trap problem

[Tom Rauch]

> > Traps made from coax are by far the worse traps I tested
for
> > Q, loss, and power rating.

> When you say "...by far the worse traps ..." does
> that include traps like my L/C trap with a "standard" coil
and
> coax capacitor?

Standard and coaxial traps are measured and posted at
http://www.w8ji.com/traps.htm

Four things kill coaxial traps:

1.) Capacitors formed by coaxial lines have low Q compared
to standard capacitors.

2.) Inductors must have spacing between turns and NO
dielectric between turns to have high Q. The coax ruins
that.

3.) Capacitors made from long transmission lines have more
voltage across the open end than the voltage applied to the
connection end.

4.) The RF resistance of braiding is several times greater
than a smooth conductor the same size. The fat coax has all
the unwanted distributed capacitance and weight of a very
large insulated conductor, but the series resistance of a
thin conductor.

It's really ironic how we have abandoned conventional traps
and loading coils and replaced them with systems that are
significantly worse!!! I think this came about because
manufacturers barraged everyone with commercials about how
bad the other choice was. Then they gave us an alternative
that was actually worse, with the only advantage being it
wasn't what they convinced us was so bad.

Some manufacturers have taken traps to a high level of loss
by making them long self-resonant coils without capacitors,
and even refuse to call the extra lossy traps they
"invented" traps!

73 Tom