Palstar Commander VHF-1200, Commander VHF-2000, VHF-1200, VHF-2000 Owner's Manual

VHF-1200 / VHF-2000

6 M LINEAR AMPLIFIER

Owner’s Manual

Customer Service and Sales Telephone: [phone]

PALSTAR, INC.

Command Technologies Division

9676 N. Looney Road

Piqua, Ohio 45356

U.S.A.

International: 937-773-6255

Fax: [phone]

E-mail: [e-mail]

Table of Contents

Introduction 3

Specifications 4

Unpacking Instructions 6

Installation Preparation 6

HV Transformer Installation 7

Safety Warnings and Precautions 8

Connections 9

Operating Procedure 9

Typical Operating Conditions 11

Circuit Description and Adjustments 12

Tuned Input & T/R Relay Schematic 14

Control and Bias Board Schematic 15

Meter Board Schematic 16

High Voltage Power Supply Schematic 17

VHF-1200 RF Deck Schematic 18

VHF-2000 RF Deck Schematic 19

Warranty, Service, and Returns 20

2

INTRODUCTION

The Commander VHF-1200 and VHF-2000 are Grounded Grid class AB2 linear power
amplifiers that operate on the Amateur 6 Meter band.

Over-drive and over-grid current protection is provided by an auto-reset circuit that places
the amplifier in standby if a preset grid current limit is exceeded.

Genuine CPI/Eimac 3CPX800A7 external anode triodes, with forced air cooling and
modern circuitry, insure efficient and conservative operation. The VHF-1200 uses one
tube, the VHF-2000 uses two.

6:1 Vernier reduction drives on all tuning controls allow smooth and easy tune-up.

A rear panel input tuning control allows a higher input circuit Q for excellent linearity
and a low input VSWR across the 6 Meter band.

An automatic delay circuit, for proper cathode conditioning before RF drive can be ap­plied, extends tube life. A 50 ohm resistor in the plate supply positive lead and a 200 ohm
resistor in the negative lead protect the tube in the event of an arc.

3

The Commander VHF-1200 and VHF-2000 feature a full compliment of control and me­tering functions for easy on-the-air operation.

A dual primary power transformer allows 200/234 VAC operation.

4

Specifications

Commander VHF-1200

6 M Linear Power Amplifier

• Modes: USB, LSB, RTTY, FM, & CW

• Power Requirements: 200/234VAC 50/60 Hz.

• RF Drive Power: 15-25 W Nominal; 35-40 Watts Max. For Full Output (1.2 kW PEP on

SSB)

• RF Output: 750 W maximum, FM or RTTY

• Input Impedance: 50 Ohm unbalanced; rear panel adjustable

• Output Impedance: 50 Ohm nominal

• Antenna Load: 2:1 VSWR maximum

• Harmonic Suppression: Better than -60 db down @ rated output

• Intermodulation Distortion: Better than -35 db down @ rated output

• Weight: 75 lbs (34 kg)

• Cabinet Size: 18” x 16” x 7.75” (45.7 cm x 40.6 cm x 19.7 cm)

• Tube Compliment: One 3CPX800A7 Ceramic Metal Triode

• Cooling: Forced air, pressurized chassis

Specifications

Commander VHF-2000

6 M Linear Power Amplifier

• Frequency Range: 50 to 54 MHz

• Modes: USB, LSB, RTTY, FM, & CW

• Power Requirements: 200/234VAC 50/60 Hz.

• RF Drive Power: 15-25 W nominal - 35-50 W Max. for full output (1.5 kW PEP on SSB )

• RF Output: 1500 W maximum, FM or RTTY

• Input Impedance: 50 Ohm unbalanced; rear panel adjustable

5

• Output Impedance: 50 Ohm nominal

• Antenna Load: 2:1 VSWR maximum

• Harmonic Suppression: Better than -60 db down @ rated output

• Intermodulation Distortion: Better than -35 db down @ rated output

• Weight: 75 lbs (34 kg)

• Cabinet Size: 18” x 16” x 7.75” (45.7 cm x 40.6 cm x 19.7 cm)

• Tube Compliment: Two 3CPX800A7 Ceramic Metal Triodes

• Cooling: Forced air, pressurized chassis

UNPACKING

Carefully remove your VHF-1200/VHF-2000 Amplifier from its shipping carton making
sure there is no damage evident from shipping. If there is any damage, notify the delivering
shipper immediately, fully describing the damage.

The HV power transformer was shipped separately, as its weight would damage the cabinet
in transit.

The 3CPX800A7 tube(s) are packed inside the cabinet in the area where the transformer
will be installed.

Do not destroy the packing material since it may be reusable later, should you require fac­tory service or need to transport the Amplifier for any other reason.

TRANSFORMER INSTALLATION

See the illustrated procedure on page 7 to complete installation.

TUBE INSTALLATION

Carefully remove the 3CPX800A7 tube(s) from the shipping carton. This carton was located
in the area where the transformer was installed. Place the tubes in the tube socket with the
proper pin alignment. If you have maintained the proper pin alignment, the tubes should go into
their sockets easily. If you have to use undue force to insert the tubes, you may have the wrong
pin alignment or one or more of the pins may be bent. If necessary, carefully straighten pins
with needle nose pliers and reinstall. Install the anode straps on the tube caps as shown and re­place the top and bottom covers. The unit is now ready for operation.

6

200/234 VAC Operation

The Commander VHF-1200 and VHF 2000 come factory wired for 234 VAC operation. For
best operation, you should use a dedicated 234 VAC main capable of supplying 20 Amps of
peak AC current.

Commander Amplifiers manufactured for export are wired for 234 VAC or 200 VAC de­pending on the final destination.