Palstar AT2K Instructions (

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

 2000 W PEP SSB, 1500 W single tone

 160 m to 6

 Variable capacitor with vernier drive

 Dual movement cross needle meter

 5” x 14.5” x 13.5”

m

PALSTAR

AT2K 2000 Watt Antenna Tuner

Technical Manual

9676 N. Looney Rd,
Piqua, OH 45356 USA

[phone]

[phone]
[phone] (Fax)
www.palstar.com

PALSTAR

Designed and Manufactured in the USA

Copyright 2018 Palstar, Inc.

AT2K SPECIFICATIONS

 METERING: Dual movement cross-needle power

and frequency compensated coupler

 INPUT & ANTENNA TUNING: Variable capacitor 413pF 4.5 Kv

6:1 Vernier Drive

 INDUCTANCE: 25 μH roller inductor; 12 ga. wire wound

on steatite ceramic core, silver plated

bar and wheel

 ANTENNA SELECTOR SWITCH: 6 position:

Coax 1 - tuned and tuner bypass

Coax 2 - tuned and tuner bypass

Switch wafers are 3 kV rated

 POWER RANGE SWITCH: 2 position 300 W / 3000 W

 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

 FREQUENC Y COVER AGE: 1.8 - 54 MHZ

 POWER MAXIMUM: 20

 IMPEDANCE R ANGE: 20 to 1500 Ω , 160m to 6m

 BALANCED OUPUT: 4:1 current type balun (optional external)

 DIMINSIONS: 5” H x 14.5“ W x 13.5” D

 WEIGHT: 13 LBS, 6 Kg

 CHASSIS & COVER: 11 ga., .090 gold Iridite Treated Aluminium

00 W PEP SSB, 1500 W single tone

(assuming resisitive load)

Reduce power for lower Z-range

AT2K GENERAL DESCRIPTION

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
conguration.

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.

Page 2 PALSTAR

INSTALLATION

REAR PANEL

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.

2.1 mm
FEMALE plug

Grey

TRACE ID

Protection

Reverse diode

Red Heat Shrink

cover

+

To 12-13.8v
Power Supply

-

AT2K DC POWER CORD

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 amplier, connect

your transmitter to the linear amplier input and the

linear amplier output to the AT2K.

DO NOT USE MORE THAN 1500 WATTS (single tone)

through the tuner.

Page 3

COAX 1 coaxial connector

for output to Antenna 1

RF INPUT

coaxial connector
for input from transmitter
or amplier

COAX 2 coaxial connector

for output to Antenna 2

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

PALSTAR

FRONT PANEL DESCRIPTION

1 2 3 4 5

6 7 8 9

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.

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.

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:

Page 4

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

PALSTAR

AT2K SCHEMATIC

PALSTAR

413 413

25

Page 5

COPYRIGHT PALSTAR 2011-2014©

METER BOARD ADJUSTMENTS

INSIDE VIEW

Reverse

Low

Reverse

High

Forward

Low

Forward

High

COUPLER

VARIABLE

CAPACITORS

ROLLER

INDUCTOR

Peak
Hold

Peak Peak

Low

Power
Range

Peak
High

On/O

Page 6

METERING
ASSEMBLY

PEAK/HOLD

PCB

PALSTAR

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).

WARNING: DO NOT OPERATE THE

AT2K WITH THE COVER OFF.

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/amplier to a low power output. If your

transmitter has a TUNE position, select that position.

4. If you use a linear amplier, set it to STANDBY. Do not use

the linear amplier until the AT2K is tuned.

BAND INPUT OUTPUT INDUCTOR

SUGGESTED ACTUAL SUGGESTED ACTUAL SUGGESTED ACTUAL

160 M

80 M

40 M

20 M

50

55

45

50

65

45

56

60

32

183

239

264

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.

17 M

15 M

12 M

10 M

6 M

50

24

24

26

40

60

35

35

40

30

267

268

271

274

265

Page 7

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.

PALSTAR

RESTORING THE INDUCTOR WHEEL

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.

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.

NOTES:

1. A SWR of 1:1 is best, but an SWR as high as 2:1 may be

acceptable. Check your transmitter/amplier 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 dierent 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.

Page 8 PALSTAR