Kenwood TS-830S Instruction Manual page 7

2.6 EXTERNAL SPEAKER AND
HEADPHONES
Receive audio output from the TS-830S is 1.5 watts at 4 to
16 ohms. The TS-830S has a built-in the SPEAKER plus an
external speaker jack on the rear panel. The speaker may be
an 8-ohm permanent-magnet type. 4 inches or larger. The
internal speaker is disconnected when an external speaker is
used. Headphones should also be 4 to 16 ohms im-
pedance. When the headphones are connected to the
front-panel PHONES jack, the speaker is disabled.
2.7 GROUND
To prevent electric shock, and reduce the possibility of TVI
and BCI, connect the transceiver to a good earth ground
through as short and heavy a lead as possible.
2.8 ANTENNA
Any of the common antenna systems designed for use on
the high frequency amateur bands may be used with the
TS-830S, provided the input impedance of the transmission
line is not outside the capability of the pi-output matching
network. The transmission line should be coaxial cable. An
antenna system which shows a standing wave ratio of less
than 2:1 when using 50 or 75 ohm coaxial transmission
line, or a system that results in a transmission line input
impedance that is essentially resistive, and between 15 and
200 ohms will take power from the transceiver with little
difficulty. If openwire or balanced type transmission line is
used with the antenna, a suitable antenna tuner with balun
is recommended between the transceiver and the feed line.
Methods of construction and operating such tuners are
described in detail in the ARRL Antenna Handbook, and
similar publications. For operation on the 160, 75 and 40
meter bands, a simple dipole antenna, cut to resonance in
the most used portion of the bands, will perform satisfacto-
rily. For operation of the transceiver on the 10, 15 and 20
meter bands, the efficiency of the station will be greatly
increased if a good directional rotary antenna is used.
Remember that even the most powerful transceiver is
useless without a proper antenna.
CAUTION:
Protect your Equipment — Use a LIGHTING ARRESTOR.
Mobile Station — Mobile antenna installations are critical,
since any mobile antenna for use on the high frequency
bands represents a number of compromises. Many
amateurs lose the efficiency of their antenna through
improper tuning. Remember the following points when
using the TS-830S with a mobile antenna.
The "Q" of the antenna loading coil should be as high as
possible.
The SWR bridge is a useful instrument, but unfortunately it
is quite often misunderstood, and overrated in importance.
Basically, the SWR bridge will indicate how closely the
antenna load impedance matches the transmission line.
With long transmission lines, such as will be used in many
fixed station installations, it is desirable to keep the
impedance match fairly close in order to limit power loss.
This is particularly true at the higher frequencies. The longer
the line, and the higher the frequency, the more important
SWR becomes. However, in mobile installations the
transmission line seldom exceeds 20 feet in length, and an
SWR of even 4 to 1 adds very little power loss. The only
time SWR will indicate a low figura is when the antenna
presents a load close to 50 ohms, but many mobile antennas
will have a base impedance as low as 15 or 20 ohms at their
resonant frequency. In such cases, SWR will indicate 3 or 4
to 1, and yet the system will be radiating efficiently.
The really important factor in your mobile antenna is that it
should be carefully tuned to resonance at the desired
frequency. The fallacy in using an SWR bridge lies in the
fact that it is sometimes possible to reduce the SWR reading
by detuning the antenna. Field strength may actually be
reduced in an effort to bring SWR down. Since field
strength is the primary goal, we recommend a field strength
meter for antenna tuning.
For antenna adjustments, the transceiver may be loaded
lightly, using the TUNE position instead of operating at full
power output. This will limit tube dissipation during
adjustments, and will also help to reduce interference on the
frequency. In any case, do not leave the transmitter on for
very long at one time. Turn it on just long enough to tune
and load, and get a field strength reading. Start out with the
antenna whip at about the center of its adjustment range.
Set the VFO to the desired operating frequency and then
adjust the PLATE control for a dip, and then the LOAD
control. Then observe the field strength reading. The field
strength meter may be set on top of the dash, on the hood,
or at an elevated location some distance from the car.
Change the whip length a half inch or so at a time, retune
the finals each time, and again check the field strength at the
antenna. Continue this procedure until the point of
maximum field strength is found. This adjustment will be
most critical on 75 meters, somewhat less critical on 40,
until on 10 meters the adjustment will be quite broad. After
tuning the antenna to resonance, the finals can be loaded to
full power.