Palstar LA-1K User manual

PALSTAR
LA-1K RF SENSING 1000W
DUAL HF LDMOS AMPLIFIER
Palstar products are designed by hams for hams,
carrying on the Palstar tradition for high-quality
products designed and manufactured in Ohio, USA.
Speci cations Summary
• 1000 Watts PEP CW ICAS (160m to 6m)
• RF Sensing Auto Band Switching
• Color TFT Touch Screen
• Variable Speed Fans
• 12.75” x 6.25” x 16.5”
• Weight: 27 lbs, 12.3 kg
9676 N. Looney Road
Piqua, OH 45356 USA
Phone: [phone]
Toll Free: (800)-773-7931
Fax: [phone]
www.palstar.com
PALSTAR
Designed and Manufactured in the USA
Copyright 2020, Palstar Inc.
LA-1K RF SENSING 1000W
DUAL HF LDMOS AMPLIFIER
Technical Manual

Page 1
• SSB POWER:
• CW MODE:
• FM/RTTY:
• AM:
• FREQUENCY RANGE:
• DISPLAY:
• INPUT DRIVE LEVEL:
• OUTPUT:
• ALC:
• GAIN:
• RF SENSING:
• RF OUTPUT:
• POWER SUPPLY:
• AC POWER:
• DC SUPPLY:
• POWER DEVICES:
• AUTO-PROTECT:
• COOLING:
• INTERMOD:
• PURE SIGNAL:
• CHASSIS:
• TOP COVER:
• DIMENSIONS:
• WEIGHT:
• DESIGN CONCEPT:
• WARRANTY:
LA-1K SPECIFICATIONS
Power levels up to 1000 W PEP
1000 W CW ICAS
500 W
250 W
1.8 to 54 MHz
Color TFT touch screen
45- 55W (all bands) 40-55W (typical), 60W max
3 x RF SO-239 or Type-N
Exciter power control
13 dB + or -1dB (nominal)
Auto band switching without band data
Cable from transceiver
Relay T/R switching
Internal medical grade
100-125VAC @ 15A or 200-250VAC @ 10A
NEMA 6-15R or NEMA 6-20R wall receptacle
50 VDC @ 42A
2 x 5600H 600W LDMOS
SWR/Short circuit/Over temperature
Variable speed fans (3)
Low IMD distortion > -35dB (typical)
Sample @ +10dBm @ 1kW output (rear panel)
.090 ga. aluminum
.090 ga. aluminum powder coated
12.75” W x 6.25” H x 16.5” D
27 lbs., 12.25 kg
Full compatibility with
Palstar HF-AUTO automatic tuner
One year
PALSTAR
Page 22
FAULT DISPLAY INDICATIONS
As noted below, these  ashing fault displays clear automatically on next transmission,
when fault condition is corrected.
Note that TX shows on display any time that the PTT input line is grounded.
TX BYPASS SWR: The SWR has gone high during a transmission. It may do this with a
transient SWR fault (such as an arc fault on the antenna, or lightning arrestor) The SWR
reading may be low or high after tripping but the LA-1K STAYS in bypass until you unkey
the transmitter. The “BYPASS SWR” graphic will then continue to  ash until transmit-
ting shows a lower SWR. Adjusting the antenna tuner while transmitting at high power
may trigger this indication. The LA-1K should always be in BYPASS for antenna tuner
adjustments.
SWR HIGH, TX WAIT displays: The ampli er will not key up until the SWR indication is
below 2.5:1. It is waiting for lower SWR before keying up. When you unkey, the display
continues  ashing BYPASS SWR.
SWR low, TX wait displays: The ampli er is keyed on the PTT line but waiting for RF to
be applied before transmit mode completes. (In Operate Mode) This indication does not
occur in direct keying mode if band data is present.
BYPASS Id: This fault trips to protect the transistors whenever the drain current (Id) ex-
ceeds 45.9A. This may occur with a poor load SWR that places high capacitive reactance
on the LA-1K output. If the SWR cannot be adjusted to provide lower Id values, the
LA-1K drive level must be reduced to prevent tripping. Normal Id values should never
exceed 42A at 1,000 W carrier power.
BYPASS TEMP: The LA-1K heatsink temperature has exceeded 99°C. The LA-1K stays
locked in STANDBY until the temperature has dropped below 70° C. If the power to the
LA-1K is cycled the ampli er lockout may be reset immediately providing that tem-
perature is below 99°C. Make sure the LA-1K vents are not blocked. Reduce power if
necessary.
TX OVERDRIVE: The LA-1K has detected drive levels exceeding 70 W. It has bypassed
to protect the transistors from possible damage. Drive level should not exceed 60 W.
BYPASS FQ: This fault indication displays when MARS operators transmit on a  lter
change over frequency. These are 2.002, 4.502, 9.002, and 22.002 MHz.
Frequency turns red, and the LA-1K won’t key: This can occur if you are transmitting
in a locked out frequency range such as 27 MHz CB band. The normal lockout window is
from to 25.983 MHz 28.001 MHz.
Note that if transmitting below 1.8 MHz, the LA-1K simply says TX BYPASS. It will not
operate in this frequency range. All matching adjustments must be completed at low
power.

Page 21
DIRECT MODE LA-1K KEYING
PTT
LOW INPUT
RELAY
CLOSED
OUTPUT
RELAY
CLOSED
TRANSCEIVER
APPLIES
RF
Transceiver Delay
HI-POWER
RF is now at
OUTPUT
Transceiver keying delay
set for 10 ms in this example
Selecting DIRECT KEYING mode closes the LA-1K transmit relays in direct
response to the PTT line. This way the transceiver’s built-in transmit RF delay
ensures enough time for the relays in the LA-1K to be in transmit position
before RF is applied. Approximately 11 ms is required for relay closing so if
adjustable, the transceiver keying delay should be set to a value higher than
11 ms.
NOTE: A band data cable is required in this mode. The LA-1K reverts to
normal keying without the band data cable connected.
9.5 ms
TOTAL DELAY
Before Transmit
= 15.5ms approx.
2.5ms 3.5ms
0 ms
PALSTAR
Page 2
THEORY OF OPERATION
The LA-1K RF Sensing Dual HF LDMOS amplier is a complete stand-alone RF
LINEAR amplier.
It is completely independent of data from an external source to determine
frequency for tracking from band to band. As a result of this feature the LA-1K
will function with any transmitting device without interconnecting data cable
attachments.
The LA-1K was designed to meet and exceed FCC requirements on all U.S.
amateur radio frequencies where ampliers are allowed. If this amplier is used on
non-amateur frequencies please note that specications are not guaranteed on
these out-of-band frequencies.
The power output of the LA-1K is 1000 Watts PEP CW ICAS (Intermittent Com-
mercial and Amateur Service). Under the ICAS classication, the use of the LA-1K
is designed for transmissions that are of an intermittent nature.
Intermittent operation of the LA-1K implies that no operating or “ON” pe-
riod of 1000W of Continuous Carrier Power will exceed approximately ONE
minute. On Single Side Band (SSB) voice duty there is no limit on transmit
time at full power of 1000W PEP.
Every “on” period must be followed by an “off ” or standby period of at least the
same or longer duration. The LA-1K provides a +10dBm@1kW RF tap feed at
the rear panel to provide provisions for “PURE SIGNAL” operation provided by
compatible transceivers. The level adjustment is calibrated at the factory. The
LA-1K was designed to be fully compatible with the Palstar HF-AUTO automatic
antenna tuner.
Included with the LA-1K:
• Two (2) line cords for 120VAC and 240VAC
• User manual
• Shipping box (please keep for warranty repairs etc.)
As per FCC 15.21 changes or modi cations not expressly approved by Palstar
could void the users authority to operate the equipment. No tune up procedure
exists.

Page 3
ON INITIAL POWER-UP
Display will indicate STBY mode (stand by). To switch the mode press
the “MODE” button on the touch-screen display to switch to “OPR” mode
(operational)
To change the POWER UP MODE push MENU then NEXT until SELECT
POWER UP MODE displays at the top. Now select desired POWER UP
MODE: STANDBY, LAST USED or OPERATE.
SCREEN DISPLAY ON POWER-UP
STANDBY MODE
NOTE: The wattmeter only shows the horizontal red power bar indicator
when the LA-1K is producing power.
It is recommended that for power up mode “STBY” is selected to allow
a tune sequence when using our HF-AUTO Antenna Tuner. After the
HF-AUTO is tuned, push MODE to select “OPR” for operation mode.
PALSTAR
Page 20
NORMAL MODE KEYING
HOW KEYING WORKS:
When the PTT line goes low, the ampli er won’t close it’s transmitting
output relay until it gets a solid frequency reading and switches bands. This
requires 14 ms of RF being applied.
The output relay then closes, requiring 9.5 ms to close. The total elapsed
time at this point is 23.5 ms.
The input relay then closes (it was energized 2 ms after the transmit relay)
This adds a 2.5 ms delay. High power now appears at the output.
The total delay therefore is approximately 26 ms.
RF
APPLIED
OUTPUT
RELAY
CLOSED
INPUT
DRIVE
RELAY
CLOSED
HI-POWER
RF is now at
OUTPUT
VALID
BAND
FREQ
DETECTED
Transceiver Delay
PTT
LOW
9.5 ms14 ms 2.5 ms
TOTAL DELAY
= 26 ms approx.
0 ms

Page 19
KEYING MODES
To select NORMAL MODE KEYING or DIRECT MODE KEYING press the MENU
button on the TFT display then continue to press NEXT several times until
you see the SELECT MODE OPTION. Use the arrow keys (< and >) to select
NORMAL or DIRECT KEYING. NOTE: In DIRECT KEYING MODE the LA-1K will
switch to STANDBY when a band change occurs.
PALSTAR
Page 4
OPERATIONAL MODE
OPERATIONAL MODE
(TRANSMITTING)
OPERATIONAL MODE
To switch into operational mode or “OPR” press the MODE button on the
touch-screen display until “OPR” mode (operational) is displayed. The red
power bar indicator will only be visible when transmitting.
OPERATIONAL MODE
(NOT TRANSMITTING)
ADDITIONAL FEATURES
• Automatic band selection when transmitting
• Automatic antenna selection of last used antenna output when band
selected
• Over-temperature protection by fan speed control and bypass mode if
temperature exceeds 100°C (fault temperature appears on display)
• Unit is locked in BYPASS until temperature drops below 70°C
• Frequency operation lockout from 25.99 MHz - 28.00 MHz

Page 5
OPERATIONAL MODE
BAND SELECT
To switch bands (160M, 80M, 40M, 20M-15M, 12M/10M, 6M) press the
BAND button on the touch-screen display then select the desired band.
NOTE: The LA-1K selects the proper band automatically when transmit
(PTT or Push To Talk) is activated.
Select the band by pressing the button corresponding to the desired
band. A yellow arrow below the band designation will indicate which
band is selected. Press EXIT to return to the main menu.
PALSTAR
Page 18
TROUBLESHOOTING
TX Wait: (as seen on the TFT display)
This message appears on the display when the PTT line is grounded
but no RF is present. RF must be applied with PTT line low to key the
ampli er to the transmit state.
Won’t amplify or auto-band switch when transmitting:
Solution:
Make sure that the PTT cable is connected to the transceiver. This is a
REQUIRED connection. Note that TX will show on the display when the
PTT connector sees a ground. Some transceivers must have their PTT
keying output enabled in the transceiver menu settings.
Low SWR on transceiver, high SWR on the LA-1K
Solution:
Always disable (bypass) the auto-tuner in your transceiver when driving
any ampli er.
The transceiver’s autotuner can not match loads connected to the
amplifer’s output.

Page 17
TROUBLESHOOTING
Bypass TEMP: (as seen on the TFT display)
The LA-1K is in BYPASS to protect itself from high temperatures. The
temperature will show in red when it exceeds 70°C. When the heatsink
temperature exceeds 100°C BYPASS TEMP will show on the display.
Solution:
Allow time for the heatsink to cool down below 70°C.
Operate (OPR) will automatically return. Verify that the side vents are
clear from obstructions.
High SWR or prolonged transmission in carrier modes may cause
elevated temperatures.
TX OVERDRIVE: (as seen on the TFT display)
This displays when the drive level exceeds approximately 60W.
Solution:
Reduce the drive level to prevent displaying this fault.
Bypass + Vd: (as seen on the TFT display)
The LA-1K is in BYPASS to protect from loss of +50V, drain voltage supply.
The fault should clear in a few seconds. This can occur when operating
on 120V if the drain current (Id) exceeds 32A.
Solution:
Switch the supply voltage to 240VAC or if operating on 120VAC is desired,
reduce drive power.
PALSTAR
Page 6
OPERATIONAL MODE
ANTENNA SELECT
To switch antennas between ANT 1 (Coax 1), ANT 2 (Coax 2) and ANT 3
(Coax 3) press the ANT button on the touch-screen display.
Then select the desired antenna output. This setting will automatically
select when changing bands to the last one used on any particular band.
The default value is ANT 1 (Coax 1).
Select the antenna by pressing the corresponding number on the
touch-screen display. A yellow arrow below the number of the antenna
will indicate which antenna is selected. Press EXIT to return to the main
menu.

Page 7
OTHER MENU OPTIONS
SELECT BACKLIGHT
To adjust the backlight on the touch-screen display press MENU and
then NEXT until the SELECT BACKLIGHT LOW or SELECT BACKLIGHT HIGH
screen appears.
SELECT BACKLIGHT LOW/HIGH
Press and hold the < or > buttons to adjust BACKLIGHT LOW (the screen
intensity used when no buttons are pressed). Click NEXT until the SELECT
BACKLIGHT HIGH screen is displayed (the screen intensity used when
buttons are being pressed) and use < or > to adjust.
Press EXIT to return to the home screen.
PALSTAR
Page 16
AM/FM POWER SET PROCEDURE
TROUBLESHOOTING
Bypass SWR: (as seen on the TFT display)
The LA-1K is in BYPASS to protect itself against high SWR. This indication
appears when the SWR is (or has been) over 2.5:1 during a transmission.
Transient faults such as antenna arcing can show a low SWR after the fault
event while the transmitter is still keyed up.
Solution:
Make sure the correct LA-1K antenna connector is selected.
Verify that your HF-AUTO or other tuner has obtained a good match while
the LA-1K is in standby. Attempting to tune at high power can cause this
alert.
With some auto-tuners it may be necessary to select manual mode after
obtaining a low SWR to prevent unwanted tuning in the middle of your
transmission.
If antenna arcing or loose connections are suspected, try the ampli er
on a dummy load. If it works normally there is likely some type of
intermittent SWR problem.
For AM mode set the carrier no higher than 250 Watts. AM peak power is
4 x the carrier level.
Transmit Fault Indications

Page 15
POWER SUPPLY PERFORMANCE
If the LA-1K is used with 120VAC the max current rating is 33A. The
DRIVE LEVEL on some of the bands may need to be reduced.
If the current exceeds 33A, the power supply will shut down and the Vd
reading on the LA-1K’s display will read ZERO; “BYPASS + Vd”.
The power supply will immediately come back on in 1 to 2 seconds and
the TFT display will read 50V. Reducing the DRIVE LEVEL will prevent
this from occuring.
The medical grade power supply of the LA-1K was designed to behave
this way and will not be damaged.
When using the LA-1K with a 208-250 VAC supply, operation at 1000W
PEP is available on all bands. It is recommended that 240VAC be used for
all modes.
PALSTAR
Page 8
OTHER MENU OPTIONS
SELECT ALC BASE VALUE
To adjust ALC base value push the MENU button on the touch-screen
display and then NEXT until the following screen appears:
Press and hold the < or > buttons to increase or decrease the ALC BASE
VALUE. If using ALC this should be adjusted carefully to match your
transceivers requirements. See the section titled “ALC ADJUSTMENT
PROCEDURE” for further instructions.

Page 9
ALC ADJUSTMENT PROCEDURE
NOTE: Ampli er ALC is only used for SSB voice transmission.
• Connect the ALC cable from transceiver to the LA-1K ampli er
• Set the ALC BASE VALUE to minimum on the LA-1K as described on
the previous page
• Place the transceiver in CW or RTTY (NOT AM or FM)
• With the LA-1K in standby mode set the transceiver to an initial
power level of about 30 Watts then unkey the transmitter
• Switch the LA-1K to OPERATE MODE (OPR) by pressing MODE
• Transmit and adjust transmitter output to achieve the desired output
power level. Do not exceed 1000 Watts output or 60 Watts drive
power (to avoid splatter). UNKEY TRANSMITTER
• Switch transceiver to LSB or USB transmission. Press MENU on the
LA-1K and NEXT until the SELECT ALC BASE VALUE screen is visible.
Transmit speaking in the microphone and adjust the LA-1K ALC base
value increasing the ALC voltage until the power output starts to
drop. The point where power drops slightly is the correct setting.
Push EXIT to return to the main screen on the LA-1K
NOTE: More precise adjustments may be made by connecting an
oscilloscope to observe the output for clipping.
PALSTAR
Page 14
HOW TO UPDATE FIRMWARE
DOWNLOADING and INSTALLING LA-1K FIRMWARE
• DOWNLOAD the latest Firmware  le (a ZIP archive) from the Palstar
website: http://www.palstar.com/en/la-1k/. The download link is near
the bottom of the page. The link to the  le is named “LATEST FIRMWARE
LINK: LA-1K FIRMWARE x.x.ZIP” where x.x is the latest revision number.
• SAVE the ZIP  le to a location on your computer
• OPEN the folder by right-clicking on the ZIP  le and select “Extract All” -
follow the steps in the Extraction Wizard. After extracting, a FOLDER will
be created called “la-1k_ rmware_XX” where XX is the revision number.
• CONNECT one end of the USB cable to a USB port on your computer.
• DOUBLE-CLICK “LOAD_LA-1K.exe” within the folder containing the
 rmware download.
• Follow the instructions on the opened computer window and use the
“Browse” button to select the  rmware version to be loaded.
• Press and HOLD the GREY button to the right of the USB port labeled
“PROGRAM UPDATES” during the next two steps.
• CONNECT the other end of the USB cable to the LA-1K front panel. A
“Found 1 Device” message will appear on the right side of the opened
computer window.
• TURN ON the LA-1K.
• RELEASE the GREY button on the LA-1K front panel.
• CLICK on the “Update Firmware” button that is on the opened computer
window. Wait until the green bar in the middle of the computer window
shows that the programming completes by scrolling from left to right.
The  rmware version number on the LA-1K is on the bottom line of the
start up screen.

Page 13
EXTERNAL DATA CONNECTORS
The LA-1K automatically selects bands and it is normally NOT
necessary to connect band data cables between your transceiver and
the LA-1K ampli er.
Radio Interface (ICOM/YAESU) Connector
This connector is designed to be pin compatible with other ampli ers.
The required cables are widely available. They can be used to connect to
the ICOM and YAESU transceivers.
RS-232 Band Control (Kenwood) Connector
This connector is designed to be used with Kenwood transceivers for
band selection using a null modem adaptor. It is also designed to control
the ampli er from a computer.
PIN FUNCTION
1 BCD B IN
2 BCD A IN
3 Kenwood RX
(data IN) *
4 Kenwood TX
(data OUT) *
5 ICOM Band Data
6 GROUND
7 Amp-Key IN
8 BCD D IN
9 BCD C IN
PIN FUNCTION
1 N/C
2 RS-232 Transmit
3 RS-232 Receive
4 N/C
5 GROUND
6 N/C
7 RTS
8 1kΩ Pullup Resistor
to +12V *
9 N/C
* Custom cable required * Required with Kenwood transceivers
XCVR Interface
(Radio Interface Pinout) RS-232 Band Control (Kenwood) Pinout
PALSTAR
Page 10
PREVENTING DAMAGE
TO THE LA-1K
WARNING
TO PREVENT DAMAGE TO THE AMPLIFIER:
Never drive input power in excess of 60 Watts.
Never use a tuning pulser in CW full break-in mode. The LA-1K was NOT
designed for full break in CW operation Very high speed full break in
keying which toggles the PTT line can lead to ampli er damage.
Never block the air vents of the LA-1K. Without proper air ow, excess
heating of internal components may occur.

Page 11
REQUIRED CONNECTIONS
Required connections are: RF IN, RF OUT and PTT.
The phono input PTT can be activated by any transceiver with a PTT
cable from the LA-1K to the transceiver (not supplied). When PTT is
grounded TX is displayed and the LA-1K is ready to transmit.
Rear Panel RF Deck Front Panel
AC Input Filter +/- 12V (bias)
Dual Output
Filters
+50V @ 42A
Power Supply
PALSTAR
Page 12
EXTERNAL DATA CONNECTORS
Table of YAESU/ELECRAFT
Band Selections and
4 Bit BCD Codes
Table of ICOM
Bands and Voltage
Level (Pin 5)
0 = low voltage (0 V)
1 = high voltage (5 V)
Band DBCA
60m 0000
160m 0001
80m 0010
40m 0011
30m 0100
20m 0101
17m 0110
15m 0111
12m 1000
10m 1001
6m 1010
NC 1111
NC 0 V
160m 7.5 V
80m 6.5 V
40m 5.5 V
30m 0.5 V
20m 4.5 V
17/15m 3.5 V
12/10m 2.5 V
6m 1.5 V
MARS Frequency
Usage
Range 2.011-25.401 MHz
Power Level 400 W
Emissions 3K00J3E/J2D
NOTE: 30M is NOT a separate band on the
LA-1K. When the band voltage drops to
zero, the LA-1K correctly switches to 20M.
This allows operation on the 30M band but
without “DIRECT KEYING” due to cable
detection by checking for voltage on ICOM
band data input. 30M is limited to 200W
and ampli er operation is not normally
required on this band.