and to do tuning to the maximum of
RF-voltage across the trap.
RF –voltage is leaking to the main at other amateur ranges, traps
in main’s wire must be installed for each of these ranges. The
basic requests for the traps are the traps must have
as possible high Q-factor and the traps must be shielded
from each other. Distance between a screen and coils should be
not less half of diameter of the coil. Table
1 shows data for trap intended for amateur ranges from
160 up to 10 meters. Air dielectric variable capacitor of 10 -100-pF
is used for tuning the traps.
Figure 4 shows schematic and construction for symmetrical retuning
main filter. You may try to do the filter if you have leaking
of RF energy to the main at several amateur bands. Data for coils
takes from Table 1. The filter is tuned or by a LED (see
Figure 1) or by a RF- voltmeter.