ATR-20 Instruction Manual
Ameritron Antenna Tuner
5
9. After adjusting the tuner for minimum SWR, the amplifier may be turned on. The
METER
switch
should be placed in the HI position, and the amplifier tuned according to the manufacturer's
instructions.
10. For quick retuning of the tuner, record the control settings for each band and use them as starting
points.
Note:
Maximum power handling occurs when both the
TRANSMITTER
and
ANTENNA
capacitors are set at the lowest front panel numbers that permit matching the antenna.
Following this guideline will insure maximum power handling capability and efficiency, and
the least critical tuning adjustments.
4.0 OPERATING
HINTS
1. While this tuner is designed to have the largest tuning range possible, there are limits to the range of
individual components. Some antennas may require either more or less capacitance, or more or less
inductance than practical components provide. In these special cases, SWR may not reduce to 1:1. If
the SWR is higher than acceptable, changing antenna or feedline length will probably bring the
antenna impedance within the useful tuning range.
2. When adjusting the tuner, use the lowest number on the
TRANSMITTER and ANTENNA
, and the
highest
INDUCTOR
number, that produces a good SWR. This reduces tuner losses and increases
tuner power rating.
WARNING:
1.
Never
operate the tuner with the top removed. Voltages inside the tuner can cause painful RF burns.
2.
Never
rotate the
ANTENNA SELECTOR
switch while transmitting. Doing so may permanently
damage the switch.
3. If you use balanced or single wire feedlines, locate the tuner where the rear terminals can
NOT
be
contacted by people, wiring, or metallic objects. The single wire and balanced line connections will
generally have high voltages when used. Be sure the tuner case is properly grounded.
4. Disconnect
all
antennas from the tuner during lightning storms. Do not depend on lightning
“protectors”.
5. Tune with low power (i.e. less than 100 watts). Apply high power only after tuning up.
4.1
In Case Of Difficulty
If the tuner fails to tune,
double check
all connections and follow the tuning procedures again. Be sure
to use
enough inductance
(lower number) and have the
capacitors open far enough
(higher front panel
numbers).
If the tuner
arcs
at the rated power levels,
double check
all connections and follow the tuning
procedures again. The typical RF power rating of this tuner is 1200 watts PEP into load impedances
between 25 and 800 ohms, and less into higher or lower impedance loads. Always use the
least amount
of inductance
(highest number) and the
greatest capacitance
(lowest number) possible that still allows
matching the load on the operating frequency.
Note:
If internal arcing occurs it may be necessary to reduce transmitter output power or modify
antenna or feedline length.
Содержание ATR-20
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