- 22 -
Lightning Protection
Modern solid state amateur equipment is particularly vulnerable to damage from lightning or
static induced transients that may appear on transmission lines.
Troubleshooting
Check out your installation again, looking for loose connections and checking all dimensions.
Then refer to the list of possible symptoms below:
Symptom: Few or no signals heard: bands seem
dead
, SWR is very high.
Look for:
Open or shorted feedline, open or shorted matching line, broken connection at base of
antenna (feedpoint).
Symptom: High SWR on 20 meter; other bands OK.
Look for:
Missing matching line. Antenna not properly tuned. 20 meter radials not present or
wrong length. Consult instructions for tuning and radial information; install matching
line
RG-11 75 ohm coax, 11 feet 4 inches if solid dielectric, 13 feet 6 inches if foam
type
. Coax cable lengths used for the matching line will vary due to the velocity factor
of the coax. You want the electrical length to be 1/4-wavelength.
Symptom: High SWR on some bands, but signals heard on all bands (conditions permitting).
Look for:
Missing or defective radial system. Install as per instructions and check connections to
radials and ground system. Keep this connection 6 inches or less.
Symptom: SWR on 15 meters seems to vary during a windy day.
Look for:
This is normal since the 15 meter wire is side mounted and when the antenna sways,
the distance between the 15 meter wire and main antenna will vary.
Symptom: High SWR on one band when antenna is roof-mounted. Radials are in place, but
antenna will just not tune.
Look for:
Radials of wrong length or running close to metal rain gutters or roof flashing. Tune
radials and/or reroute them away from metal.
Symptom: Tuning is
sharp
with narrow bandwidth on 80 meter (and 160 meter if
BUT-TBR-
160-S
is in place).
Look for:
Normal condition. The total length of the antenna represents such a small percent of a
wavelength on these bands that sharp tuning is a normal condition.
Symptom: Antenna was installed on the ground and tuned OK, but tuning changed over a period
of weeks or months.
Look for:
Antenna installed over poor ground system. Ground conditions have changed, causing
shift in resonance. Install radial system as per instructions. Check connection to radial
system. When you see this problem, you may assume that a ground rod without a
radial system is not enough. Vertical antennas require a good radial wire system.
Symptom: Resonant point changes during wet or icy weather.
Look for:
Normal condition.
