first,
• on a coaxial feedline near the feedpoint of any antenna; or, if you run balanced line
from the feedpoint of a balanced antenna to a balanced tuner and balun (or balun and
unbalanced tuner) at, say, the point of entry to your house, on the coax at this point;3
• on a coaxial feedline on both sides of any point where the coax shield is connected to
a rod or pipe driven into the ground, or to a counterpoise;4
• on a coaxial feedline in your shack, where the coax first reaches your tuner, amp, or
transceiver;
• on a long coaxial feedline, at intervals of one-quarter wavelength;5
• on any other cable that goes near your antennas, e.g., to a rotator, to a remote tuner or
relay/switchbox, to steppir motors, to tower lights or utility outlets, …;
• on the power cable at an outdoor compact fluorescent lamp if this cable runs
anywhere near your antennas, and also where this cable enters your house;
• on both the high- and the low-voltage sides of any solid-state transformer that feeds
low-voltage lighting near your antennas;
• at the ground-fault circuit interrupter (gfci) of any ac power circuit that goes near
your antenna.6
second,
• on every 60-hz ac power cable that feeds your shack;7
• on every other cable (antenna-rotator, telephone, tv, computer network, etc.) that
comes into your shack;
• on every cable of every computer, peripheral, keyer, tnc, switching power supply
(including wall warts and battery chargers, especially laptop-computer power adaptors)
and other device connected to your radio that oscillates, switches, or digitates;
• on the ac line cable/cord of any compact fluorescent lamp or any incandescent lamp
with a dimmer and/or solid-state transformer that is plugged into your shack circuits.8
third,
• at any identified qrn source in or around your house;9
• on the cables of an intrusion / fire / other alarm system, at panels, multiplexers,
telephone-line interfaces, radio-telemetry interfaces, 60-hz power supplies, standby
battery charger / supplies, etc.;
• on tv cables, both where they enter your house and where they reach tv sets,
converters, vcrs, dvrs, cable modems, etc.;
• on 60-hz ac power cables and any audio and video cables connected to tv sets,
music and “home theater” systems, etc.;10
• on telephone cables, both where they enter your house and where they reach telephone
sets, answering machines, cordless base stations, adsl modems, isdn
modems, pots modems, etc.; and on all power cables (e.g., from wall warts)
connected to telephone-line-connected equipment; also on the handset cords of
telephone sets.11
