Palstar products are designed by
Hams for Hams carrying on the
Palstar tradition for high-quality
products designed and
manufactured in Ohio, USA.
AT2K 2000 Watt
Antenna Tuner
l 2000 W PEP SSB, 1500 W single tone
l 160 m to 10m
l Variable capacitor with vernier drive
l Dual movement cross needle meter
l 5” x 14.5” x 13.5”
9676 N. Looney Rd,
Piqua, OH 45356 USA
(937) 773-6255
(800) 773-7931
(937) 773-8003 (Fax)
www.palstar.com
PALSTAR
AT2K 2000 Watt Antenna Tuner
Technical Manual
Designed and Manufactured in the USA
Copyright 2014 Palstar, Inc.
PALSTAR
l METERING: Dual movement cross-needle power
and frequency compensated coupler
l INPUT & ANTENNA TUNING: Variable capacitor 413pF 4.5 Kv
6:1 Vernier Drive
l INDUCTANCE: 25 μH roller inductor; 12 ga. wire wound
on steatite ceramic core, silver plated
bar and wheel
l ANTENNA SELECTOR SWITCH: 6 position:
Coax 1 - tuned and tuner bypass
Coax 2 - tuned and tuner bypass
Switch wafers are 3 kV rated
l POWER RANGE SWITCH: 2 position 300 W / 3000 W
l REAR PANEL CONNECTORS:
SO-239: RF Input, Coax 1 & 2, Bypass
COAX: Balanced line (optional balun)
END FED WIRE: High Voltage Nylon66™
terminal post & ground post
12 VDC INPUT: 14mm connector, 2.1mm ID,
5.5mm OD, center positive, 200 ma
l FREQUENCY COVERAGE: 1.8 - 54 MHZ
l POWER MAXIMUM: 2000 W PEP SSB, 1500 W single tone
l IMPEDANCE RANGE: 20 to 1500 Ω, 160m to 10m
(assuming resisitive load)
Reduce power for lower Z-range
l BALANCED OUPUT: 4:1 current type balun (optional external)
l DIMINSIONS: 5” H x 14.5“ W x 13.5” D
l WEIGHT: 13 LBS, 6 Kg
l CHASSIS & COVER: 11 ga., .090 gold Iridite Treated Aluminium
AT2K SPECIFICATIONS
Page 2 PALSTAR
Building on success, Palstar upgraded the best-selling AT1500CV
throughout to create the American-made Palstar AT2K Antenna Tuner.
The AT2K optimizes the performance of your antenna and transmitter
by providing adjustable impedance matching using a T-type circuit
conguration.
The AT2K also measures the power (upgraded to include a PEAK/PEAK
HOLD function) and Voltage Standing Wave Ratio (VSWR or SWR),
which allows you to tune the SWR to the lowest possible for the
selected transmission frequency.
The AT2K also features a precision steatite ceramic core roller inductor
with a plated roller wheel and roller shaft. The smaller size permits
operation on 6 meters.
A high voltage ceramic wafer switch allows selection between coax
feedlines or wire-fed antennas. DIRECT switch positions bypass the
impedance matching circuit but allow for the SWR, FORWARD, and
REFLECTED and PEAK power meter FUNCTIONS.
Tuning is achieved with the front panel mounted controls. The 6:1 ratio
Vernier dials allow for tuning with precision and accuracy, while the
Inductor crank handle facilitates coarse adjustments. The range of the
meter (300W/3000W) is selcted by a push button switch located on the
front panel.
AT2K GENERAL DESCRIPTION
UNPACKING
Carefully remove the AT2K from the shipping carton and
inspect it for signs of damage. If any damage is apparent,
notify the transportation carrier or dealer immediately.
KEEP THE PACKING CARTON for moving, storing, or
reshipping the tuner to us for repair if required.
LOCATION
Select a location for the AT2K that allows the connectors
to be free from any possible contact with people, pets,
or objects during operation and with unrestricted air
ow for cooling.
INSTALLATION PROCEDURE
Connect a coax cable from your transmitter to the RF
INPUT connector on the rear panel. Keep the cable as
short as possible. If you use a linear amplier, connect
your transmitter to the linear amplier input and the
linear amplier output to the AT2K.
DO NOT USE MORE THAN 1500 WATTS (single tone)
through the tuner.
INSTALLATION
Page 3
+
-
To 12-13.8v
Power Supply
2.1 mm
FEMALE plug
Grey
TRACE ID
Protection
Reverse diode
Red Heat Shrink
cover
AT2K DC POWER CORD
PALSTAR
REAR PANEL
GROUND post/wing nut
ground connector
COAX-BAL-WIRE
Use this connector
to connect an optional
external 1:1 or 4:1 balun
for balanced or wire feed
antennas
BYPASS coaxial
connector for output
to dummy load or third
coax output. Bypasses
tuner, but meter circuits
are on if AC adapter is
connected to rear panel
12 VDC INPUT
(2.1 mm plug,
center pin +)
12 VDC adapter
200 mA to power
the meter lamp
COAX 2 coaxial connector
for output to Antenna 2
RF INPUT
coaxial connector
for input from transmitter
or amplier
COAX 1 coaxial connector
for output to Antenna 1
Page 4
FRONT PANEL DESCRIPTION
1. POWER/SWR METER Dual needle meter displays FORWARD and
REFLECTED power in watts. SWR is measured where the two needles
intersect on the red scale. SWR is printed on meter face.
2. PEAK HOLD Select to read Peak Hold on the SWR meter. Peak switch [3]
must be in PEAK position.
3. PEAK Selects between PEAK and AVERAGE power metering display.
4. RANGE Two-position switch selects the range of FORWARD and
REFLECTED power displayed on the power meter. When the RANGE
button is OUT, the FORWARD meter scale reads 300 watts full scale and
the REFLECTED meter scale reads 60 watts full scale. When the RANGE
button is IN, the FORWARD meter scale reads 3000 watts full scale and
the REFLECTED meter scale reads 600 watts full scale.
5. ON Select to turn on the backlight in the meter and enable metering,
and 160 meter functions. The jack on the back panel must be supplied
with 12 VDC for these functions to work.
6. DIRECT-TUNED MODE SWITCH Six-position rotary switch selects an
output connector as follows:
1 2 3 4 5
6 7 8 9
PALSTAR
a. DIRECT BYPASS selects BYPASS COAX CONNECTOR bypassing the
impedance matching circuit, but providing SWR, FORWARD, and
REFLECTED power meter readings.
b. DIRECT COAX 1 selects COAX 1 CONNECTOR bypassing the tuner
matching circuit, but providing SWR, FORWARD, and REFLECTED meter
readings.
c. DIRECT COAX 2 selects COAX 2 CONNECTOR bypassing the tuner
matching circuit, but providing SWR, FORWARD, and REFLECTED meter
readings.
d. TUNED COAX 1 selects COAX 1 CONNECTOR through the impedance
matching T circuit.
e. TUNED COAX 2 selects COAX 2 CONNECTOR through the impedance
matching T circuit.
7. INPUT Continuosly adjustable input capacitor.
8. OUTPUT Continuously adjustable output capacitor.
9. INDUCTOR 25 H continuously variable ceramic roller inductor driven
by a crank handle. Coupled to the crank handle is a gear-driven
precision mechanical counter. The end stop readings
on the turns counter are ZERO and 279. Zero is max imum inductance and 279 is minimum inductance.
μ
AT2K SCHEMATIC
COPYRIGHT PALSTAR 2011-2014©
PALSTAR
413 413
25
Page 5
Page 6
METER BOARD ADJUSTMENTS
Reverse
Low
Reverse
High
Forward
Low
Forward
High
Peak
Hold
Peak Peak
Low
Power
Range
Peak
High
On/O
PALSTAR
INSIDE VIEW
ROLLER
INDUCTOR
VARIABLE
CAPACITORS
COUPLER
METERING
ASSEMBLY
PEAK/HOLD
PCB
Page 7
OPERATING YOUR AT2K
BEFORE OPERATING
1. To avoid possible damage to the AT2K set INPUT, OUTPUT,
INDUCTOR, and POWER RANGE switches as outlined in the
chart below before applying transmitter power.
2. Begin tuning with your transmitter/amp feeding the tuner
set at a low output power setting (50-100 Watts max).
TUNING
1. Select the band and frequency of desired operation.
2. Set TUNE and INDUCTOR controls to the suggested setting
before applying transmitter power (see chart). Actual settings
will vary from antenna to antenna.
3. Set your transmitter/amplier to a low power output. If your
transmitter has a TUNE position, select that position.
4. If you use a linear amplier, set it to STANDBY. Do not use
the linear amplier until the AT2K is tuned.
WARNING: DO NOT OPERATE THE
AT2K WITH THE COVER OFF.
BAND INPUT OUTPUT INDUCTOR
SUGGESTED AC TUAL SUGGESTED ACTUAL SUGGESTED ACTUAL
160 M
80 M
40 M
20 M
17 M
15 M
12 M
10 M
6 M
50
55
45
50
50
24
24
26
40
65
45
56
60
60
35
35
40
30
32
183
239
264
267
268
271
274
265
PALSTAR
DO NOT EXCEED 1000 WATTS AVERAGE (SINGLE TONE)
5. Set RANGE switch to 300 W (button out).
6. Set the DIRECT/TUNED mode switch to the TUNED
position matching your antenna connection. To tune your
antenna, the switch selection must be set to: COAX 1 TUNED,
COAX 2 TUNED, or BALANCED LINE.Selecting COAX 1 DIRECT,
COAX 2 DIRECT, or BYPASS bypasses the tuning circuitry and
tuning is not possible.
7. Rotate the INPUT, ANTENNA, and INDUCTOR controls for
maximum noise or signal as heard on your receiver. Refer to
preset tuning chart on page 9.
8. Key your transmitter and adjust the power level for a
reading of 50-100 watts on the FORWARD scale. Adjust the
INPUT, OUPUT, and INDUCTOR controls for a minimum
REFLECTED reading while maintaining a FORWARD reading
of 50-100 watts using your transmitter power control.
9. Read the SWR on the red scale at the point where the two
needles intersect. Repeat TUNING the input and antenna
controls until the lowest SWR reading is obtained. The SWR
should be 2:1 or lower.
10. When you have tuned your antenna to the best SWR,
record the settings of the INPUT, ANTENNA, and INDUCTANCE
controls on the chart above for future reference. When you
retune, use these settings as your starting point.
This procedure takes patience the rst time. The input
and antenna controls vary the capacitors and provide
ne adjustments, while the roller inductor crank
provides coarse adjustment.
RESTORING THE INDUCTOR WHEEL
Page 8 PALSTAR
To RESTORE wheel pressure on
the inductor push down on the
at springs soldered to the
wheel shaft located on each
end of the shaft.
When approaching the end stops of the roller inductor
(readings of Zero or 279) SLOW DOWN. Slamming the
roller wheel into the mechanical end stops on either
end of the roller inductor will decrease the pressure of
the wheel against the wire wound on the ceramic form.
NOTES:
1. A SWR of 1:1 is best, but an SWR as high as 2:1 may be
acceptable. Check your transmitter/amplier manual for
details.
2. If you cannot get an acceptable SWR, lengthen or
shorten your antenna and/or feedlines and retune.
3. If you get low SWR readings at more than one setting,
use the setting that gives:
- highest FORWARD power reading
- lowest REFLECTED power reading
- uses the largest capacitance (highest number) on the
INPUT and ANTENNA controls.
4. Any time a new or dierent antenna is connected, it is
necessary to repeat the turning procedure for each
antenna.
5. Once every 4-6 months clean the roller coil with Deoxit
D5 contact cleaner and a clean cotton cloth. Do not
remove the conducting grease on the rod that guides the
roller wheel. Do not transfer any of the conducting grease
from the rod to the roller coil body, as this will
contaminate the windings.
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