Open Half-Wave Lines; Standing Waves - Heathkit HD-1250 Manual

Open
Half-Wave Lines
Couple at the center of
the
line as
shown
in
Figure 3-10.
When
measuring coaxial
lines,
short the
lines at
one end and measure
as
for the quarter-wave shorted
line
at
the calculated 1/2 frequency. Resonant frequency
is
then
multiplied
by 2
to
determine
the correct
length of
the
line
after
you remove
the
shorting
line.
Standing
Waves
Maintain a
uniform coupling
as
you
move
the
Dip Meter along the feed-line
by
keeping the coil
form
against the
line.
This
is
possible as
the
coil
windings
are
shielded
from
direct
contact
by the
coil
coating.
A
"flat" line
is
determined
by
the
lack
of
meter
fluctuation as
you
move
the
coil
along the line.
Do
not
overload the dip meter,
it is
highly sensitive
to small changes
due
to
its
internal
amplifier.
HALF-WAVE OPEN
LINE (SHORTED)