Palstar COMMANDER VHF-144 User manual

COMMANDER VHF-144
2 METER LINEAR AMPLIFIER
—————————————————————
Owner’s Manual
PALSTAR, INC.
Command Technologies Division
9676 N. Looney Road
Piqua, Ohio 45356
U.S.A.
Custo er Service and Sales Telephone: [phone]
Fax: [phone]
E- ail: [e-mail]

2
Table of Contents
Introduction 3
Inside View 4
Specifications 5
Unpacking Instructions 6
Safety Warnings and Precautions 6
Front & Rear Layout 7
Installation Preparation 8
Operating Procedure 9
Operating Hints 10
Typical Operating Conditions Table 10
Warranty, Service, and Returns 11
HV Power Supply Sche atic 12
AC Mains & Step-Start Sche atic 13
Control & Metering Board Sche atic 14
RF Deck Sche atic 15
T/R Relay Board Sche atic 16
Voltage Doubler Power Supply Sche atic 17
PHOTO APPENDIX:
RF Deck 18
Dual Meters 19
Meter Board 20
Step-Start Board 21
Power Supply 22

3
INTRODUCTION
The Co ander VHF-144 is a grounded grid AB2 linear power a plifier that oper-
ates on the A ateur 2 eter band (144 to 148 MHz).
A single CPI/Ei ac 3CPX800A7 pulse-rated external anode triode with forced air
cooling and odern stripline circuitry ensures efficient and conservative operation.
The 6:1 ratio vernier reduction drives on all tuning controls allow s ooth and easy
tune up, while the front panel input tuning control allows a higher input circuit "Q" for
excellent linearity which presents a low input VSWR to the exciter across the entire
2 eter band.
An auto atic delay circuit, for proper cathode conditioning before RF drive is applied,
which extends tube life. This is prefor ed by a icroprocessor, which also controls a
step/start dual relay syste for a safe and effective control AC input startup.
The Co ander VHF-144 features a full co pli ent of control and etering func-
tions for easy on-air operation. By using 2 cross-needle etering, it allows viewing of all
functions si ultaneously.
This processor also features a gird-trip at 70 a of grid current. When activated by
overdriving the a plifier, the green LED will flash at a high rate.
Reset is provided by switching the operate/standby switch fro operate to standby and
back again.
A dual pri ary power transfor er allows 117VAC, 200VAC or 234VAC operation.

4
High Voltage
Transfor er
T/R Relay
Board
Ball
Bearing
Cooling
Blower
Load Tuning
Capacitor
Input Tuning
Piston Capacitor
3CPX800A7
Triode Tube
Fila ent
Transfor er
High Voltage
Interlock
Switch
Duel Meter
Control
Board w/ Mutliple
LED Backlighting
High Voltage
Board
Commander VH -144 Inside Layout
AC Input
Socket Step/Start
PCB

5
Specifications
Co ander VHF-144
2 Meter VHF Linear Power A plifier
• Frequency Range: 144 to 148 MHz.
• Modes: USB, LSB, RTTY, FM, CW.
• Power Require ents: 200/234VAC 50/60 Hz.
• RF Drive Power: 10 to 15 Watts no inal; 30 Watts axi u , for full 1 KW (CW) output.
• Grid-trip Current: 70 a
• RF Output: 1 Kw pep (USB, LSB); 650 Watts cw FM, 450 Watts.
• Input I pedance: 50 Oh s unbalanced, front panel adjustable.
• Output I pedance: 50 Oh s no inal.
• Antenna Load (VSWR): 2:1 axi u .
• Har onic Suppression: better than 60db down at rated output.
• Inter odulation Distortion: better than 35 dB down at rated output.
• Weight (with transfor er): 43 lbs. (19.5 Kg).
• Cabinet Size: 14.5'' x 14.5'' x 6'' (36.8c x 36.8 c x 15.2 c ).
• Tube Co pli ent: one 3CPX800A7 cera ic pulse-rated etal triode.
• Cooling: pressurized chassis forced air, with a die cast bearing blower.
• Antenna Relay: DPDT; .1 dB insertion loss.
• Fuse: Type SFE; 234VAC and 200VAC operation: 15 A p.
• Fe ale AC plug on a 6’ 12ga 3-wire line cord included

6
UNPACKING INSTRUCTIONS
Carefully re ove your Co ander VHF-144 fro its shipping carton aking sure there is
no da age evident fro shipping. If there is any da age, notify the delivering shipper i e-
diately, fully describing the da age.
Do not destroy the packing material, since it ay be reusable later, should you require
factory service, or need to transport the A plifier for any other reason.
CAUTIONS:
• DO NOT atte pt any type of service or repair on this a plifier without first re oving the
AC power and allowing AT LEAST 10 MINUTES FOR THE HIGH VOLTAGE CAPACI-
TORS TO BLEED OFF !
• DO NOT operate this a plifier with the top or botto covers re oved. DO NOT operate
this a plifier with the internal RF tube co part ent covers re oved.
• CONTACT WITH VOLTAGES IN THE CABINET CAN BE FATAL ! CLOSE QUAR-
TER EXPOSURE TO UNSHIELDED RF AT THESE POWER LEVELS AND FRE-
QUENCY IS HAZARDOUS TO YOUR HEALTH !
• Never atte pt operation without first connecting an appropriate antenna (2:1 VSWR Max)
or a 50 oh du y load with sufficient rating or SERIOUS DAMAGE TO THE AMPLI-
FIER MAY RESULT.
• Never operate the a plifier with ore drive than required to produce the rated output for
the operating ode used (Max 25-30 Watt).
• Do not place the Co ander VHF-144 in repeater operation. This a plifier is not designed
for unattended service. Extensive odification would be required for this type of service.
• Never operate any a plifier using an extension cord.
IF ANY SITUATION YOU ARE NOT SURE ABOUT OCCURS,
PLEASE CONTACT MANUFACTURER FOR ASSISTANCE.
!! WARNING !!
CONTACT WITH VOLTAGES IN THIS AMPLIFIER CAN BE
!!! FATAL!!!

7
Ground Lug
Multi eter:
Plate Current/
Plate Voltage
TUNE Control
Multi-turn Piston Capacitor
Preset at Factory
Multi eter:
Relative
Output/Grid
Current
LOAD
Control
INPUT
Control
STANDBY/
OPERATE
Switch
ON/OFF
Switch
Power Ready
Light
RF In
RF Out
Bypass SWR
Adjust
Rear Panel Layout
ront Panel Layout
AC Power
Socket
(PTT) Key

8
INSTALLATION PREPARATION
The Co ander VHF-144 is factory wired for operation fro an 234VAC line. Operation at
the full rated output should not be atte pted unless the AC line is capable of supplying at least
15 a ps of peak current. It is strongly reco ended that you operate this a plifier fro a
234VAC line.
Install an appropriate plug on the end of the power cord to ate with your wall receptacle.
If you change the operating voltage as described above, be sure to install the proper fuse.
The fuse is a type SFE, 20 A p for 234 VAC & 200 VAC operation.
All Co ander VHF-144 a plifiers anufactured for export are wired for 200 or 234VAC,
50 or 60 Hz, depending on the final destination. No plug is supplied with the AC line cord.
Location of your Co ander VHF-144 requires that no equip ent be placed directly
against the left side vent, as air expelled fro the tube exhaust can beco e quite hot. Allow at
least 3 inches clearance on the side of the unit and between other equip ent.
To switch fro trans it to receive the Co ander VHF-144 requires a contact closure or
keying circuit capable of sinking 15 a of positive voltage (12 VDC open circuit) to ground.
This connection is ade to the RCA jack on the rear panel arked KEY. Read the anual that
ca e with your transceiver to deter ine the proper external connections. On so e transceivers,
this is not provided, and an alternate circuit will be required. Always use shielded cable for
these connections.
Connect a good quality thru-line analog Watt eter between the a plifier output jack and the
antenna or du y load using RG8 or better coax.
Connect the exciter (transceiver) RF output to the a plifier input using 50 oh coax.
Connect a ground lead, as short as possible, fro earth ground to the Co ander VHF-
144’s rear panel ground ter inal.
!!CAUTION!!
BE SURE YOU HAVE REMOVED THE LINE CORD PLUG FROM YOUR WALL
SOCKET BEFORE REMOVING THE JUMPER COVER. IF YOU FAIL TO UNPLUG
YOUR AMPLIFIER, YOU WILL EXPOSE YOURSELF TO LETHAL VOLTAGES.
AC SOCKET CONNECTIONS
White
(Natural)
Green
(Ground)
Black
(230 VAC)
Black
White
Green
Amplifier Wall Outlet

9
OPERATING PROCEDURE
After reading this anual and co pleting the Installation/Preparation Instructions, position
the Co ander VHF-144 front panel controls as follows:
• ON/OFF — OFF
• OPERATE/SSTANDBY — STANDBY
• INPUT — CENTER ON SCALE (50-55 on Scale)
• LOAD — MINIMUM (COUNTER-CLOCKWISE) (100 on scale is ini u capaci-
tance)
• TUNE — LEAVE AT FACTORY SETTING (NOTE: the TUNE control is a ulti-turn
piston capacitor and was factory preset for operation at 144.200 MHz.
actory Setting Tune is 55.
After presetting these controls, switch the ON/OFF switch to the ON position. The eter
la ps will illu inate, the blower will be running and plate voltage will be approxi ately 2800
VDC.
The 3CPX800A7 used in this a plifier requires a war up period before RF drive ay be
applied, to prevent da age to the tube. A 2 inute war up is provided by a icroprocessor
circuit. During war -up the green LED will flash at 1sec rate. At the end of the war -up pe-
riod, the green POWER LED on the front panel illu inates on fully and the unit is ready for
operation.
Switch the OPERATE/STANDBY switch to the OPERATE position and key the exciter with
ZERO RF drive applied. The Red Trans it light should illu inate, the tube will be biased
“on”, and plate idling current should be approxi ately 60 a. as displayed on the Ip eter
scale.
Apply a very low RF drive (less that 5 watts) and adjust the INPUT control for a peak in the
plate current (Ip) on the eter. Next adjust the TUNE control for axi u output as indicated
on an external Watt eter. DO NOT adjust the LOAD control at this ti e. COMPLETE
THESE ADJUSTMENTS AS QUICKLY AS POSSIBLE TO AVOID STRESSING THE
TUBE.
Key the exciter in FM Mode (For Tune Procedure), and while increasing the RF drive, adjust
the LOAD control clockwise in order to keep the grid current below 40 a. and to obtain a peak
in output power on an external watt eter (see chart: Typical Operating Conditions chart on the
next page).
Re-peak the TUNE control for axi u output at 600 a of plate current.
The Co ander VHF-144 is ready for SSB or CW on the air operation. Nor al SSB opera-
tion is indicated by plate current readings on voice peaks of approxi ately 1/3 to 1/2 of the CW
key down value.
For FM or other high duty cycle odes, li it drive to 10-15 watts axi u .

10
OPERATING HINTS
The Co ander VHF-144 TUNE control is a high "Q" piston-type tuning capacitor with a 6:1
ratio vernier reduction drive. This control requires about 15 revolutions to tune the unit fro
144 to 148 MHz.
Unless you have specified another band seg ent, the unit is factory tuned at 144.200, the na-
tional SSB calling frequency. If you use the Co ander VHF-144 ainly for CW and SSB,
and after having tuned the unit to your antenna, you will be able to QSY up or down the CW/
SSB band seg ent without aking any tuning adjust ents. Unless so eone changes these ad-
just ents, it will not be necessary to retune the a plifier each ti e you operate it. Just turn the
unit on, wait for the green light and begin trans itting.
If you decide later to operate in the FM portion of the band, it is best done by tracking up the
band about 500 KHz at a ti e. To do this, key the exciter with low drive (5 watts or less), re-
tune INPUT for a peak in plate current (Ip), and readjust TUNE control for axi u output,
repeating this procedure as you ove up the band. This is also useful if you happen to forget
where you left it tuned.
TYPICAL OPERATING CONDITIONS
DRIVE GRID CURENT PLATE CURENT POWER OUTPUT
12.5 Watts 15 a 400 a 450 Watts
18.5 Watts 25 a 500 a 650 Watts
30 Watts 35 a 600 a 1000 Watts

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Limited Warranty
Palstar Inc. warrants the Co ander VHF-144 to be free fro defects in aterial and work-
anship under nor al use and service for a period of one (1) year from the date of delivery
to the first buyer (the “Warranty Period”). Palstar Inc.’s obligation under this warranty is li -
ited to repair or replace ent of the product at it’s option at the Palstar factory in Piqua, OH.
This warranty is effective only when the product is returned to the factory with all transpor-
tation charges prepaid and exa ination of the product discloses, in Palstar’s judg ent, to have
been defective during the Warranty Period.
The Warranty Period shall not extend beyond its original ter with respect to interi in-
warranty repairs by Palstar. This Warranty Period shall not apply to any product which has been
repaired or altered by anyone other than Palstar without prior written authorization. Warranty
does not extend to any products which have been subject to da age fro i proper installation,
application or aintenance in accordance with the operating specifications. Palstar neither as-
su es nor authorizes any person to assu e for it any obligation or liability other than herein
stated.
Shipping Your Amplifier Back to the actory
Due to the necessity of shipping the a plifier with the HV transfor er re oved, please
contact the factory for instructions before sending an a plifier back to us. There are circu -
stances in which it ay not be necessary to return the HV transfor er, thereby saving you ship-
ping charges. When you call, Palstar will infor if transfor er return is necessary. If trans-
for er return is necessary, re ove it fro the a plifier cabinet and ship it separately, prefera-
bly in its original crate.
Repair Policy
When sending in a product for service, see the section above. If not using the original pack-
ing aterials, please “double” box it carefully and ship it insured for your protection. Please
include a note clearly describing the proble , how you wish the ite returned and how you
wish to pay for the service. Package your unit properly. Palstar, Inc. is not responsible for er-
chandise da aged in ship ent. Our service rate is $30 per hour (1/2 hr. ini u ).
Return Policy
All returns ust receive prior authorization fro Palstar. Returned ite s ust be received in
original—AS SHIPPED—condition including the original box, anuals, accessories, and copy
of sales receipt. Returns ust be within 14 days of purchase. Returned ite s are subject to a
20% restocking fee. Shipping is not refundable.

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Commander VHF-144 HV Power Supply

13
AC Mains and Step-Start Board (VHF-144)
~13.5VAC

14
Control and Metering Board VHF-144

15
F Deck VHF-144

16
Commander VH -144 T/R Relay Board

17
Commander VH -144 Voltage Doubler Power Supply Board

18
RF Deck
3CPX800A7
Triode Tube
Load Tuning
Capacitor Input Tuning
Piston Capacitor
RF Plate Choke
Plate
Capacitor
120pf/7.7kv

19
Dual Meters
Grid Current: Scale
0-60 a Single Tube Top
0-120 a Two Tubes Mid
0-180 a Three Tubes Botto
Grid Current: Scale
0-600 a Single Tube Top
0-1200 a Two Tubes Mid
0-1800 a Three Tubes Botto

20
Meter Board
Cathode
Fuse