M2 ANTENNA SYSTEMS 6M 1K2 User Manual

M2 Antenna Systems, Inc.

Model No: 6M-1K2

6M High Power Amplifier

Operating Instructions

PLEASE READ BEFORE USE AND SAVE

M2 Antenna Systems, Inc. 4402 N. Selland Ave. Fresno, CA 93722

Tel: [phone] Fax: [phone] Web: www.m2inc.com

©2011 M2 Antenna Systems Incoporated

4/18/13
Rev.02

TROUBLESHOOTING OVERVIEW INSTALLATION

ADDENDUM

WARRANTY

CONTENTS

OVERVIEW

SECTION...........................................................PAGE

COVER PAGE ........................................................1

CONTENTS...........................................................2

OVERVIEW...........................................................3

Introduction.................................................3

Features ......................................................3

Major Components........................................4

Theory of Operation......................................6

INSTALLATION......................................................8

Typical Installation Diagram...........................8

Installation Considerations.............................8

TROUBLESHOOTING.............................................9

Troubleshooting Guide ..................................9

Support, Service and Returns ........................10

Schematic Diagram.......................................11

ADDENDUM..........................................................12

Parts List......................................................12

Specifications...............................................13

WSJT: What Is It and How Do I Get It?..........14

WARRANTY ..........................................................16

M2 Antenna Systems, Inc.

4402 N. Selland Ave. Fresno, CA 93722

Tel: [phone] / Fax: [phone]

http://www.m2inc.com

©2011 M2 Antenna Systems Incoporated

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OVERVIEW

INTRODUCTION

It is with great satisfaction that M2 now offers a true breakthrough in high power VHF amplifiers. Our goal has always
been to offer the most carefully designed, high performance antenna products. Now we offer the same high performance
in VHF amplifiers. The 6M-1K2 and the 2M-1K2 utilize the new Freescale™ LD MOS FET (MRFE6VP6IK25H), a single
device specified to produce 1.25 kW with as little as 3 watts of drive from HF to 600 MHz. This is amazing in itself, but
adding its inherent stability driving that power into a 65:1 mismatch is equally incredible. It can do all this at efficiencies
well above 60%!

YOU CAN SEE WHY WE ARE EXCITED!

Here is where M
will fit in a suitcase. We wanted it to be light and it is at just 13 lbs (5.9 kg). The optional integrated 2400 watt switching
power supply adds only another 7.5 lbs to this incredible package that travels easily at 20.5 lbs (9.3 kg). Additionally, the
power supply may be purchased as a separate, stand alone accessory.

Now, at home in your shack you won’t need that big steel rack any more. All you need is a small desktop or shelf to hold
your QRO (high power) VHF amplifier.

Above all we made this amplifier easy to understand and operate. The photo below shows the model with the amplifier
and the power supply integrated together (7.125” wide, 9” high 14” deep).

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comes in. We wanted to make it small and we did; 6 x 7.125 x 13.5 inches (152 x 181 x 343 mm) so it

OVERVIEW

FEATURES

By now you may realize that there is a lot more in this amplifier
package than just a 1.25 kW LDMOSFET.

What you can’t see in pictures is listed proudly below:

• A complete and accurate high power VSWR bridge.

• Regulator PC board with high wattage power resistors and

two voltage regulators.

• Medium power input power coaxial relay.

• High power, high speed vacuum relay easily capable of

handling full output power.

• Monitoring via high accuracy DC current and temperature
monitoring devices.

• Sophisticated output RF filter reducing spurious harmonics
to exceed FCC regulations.

• Quiet fan on the bottom cools miniature RF tank and filter
components.

• 50 or 100 watt input attenuator that reduces your input
power to safe drive levels.

Frescale™ is a registered trademark of Freescale Semiconducto r, Inc.

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OVERVIEW

MAJOR COMPONENTS, 6M-1K2

FRONT PANEL

OVERVIEW

1. +50V LED (Yellow). Indicates +50 VDC is present from the power supply

2. Ready LED (Green). Lights when the Power switch is on and the amplifier is ready to be keyed and driven.

3. VSWR/TEMP LED (Amber). When lit, indicates an excessive VSWR condition (2.5:1 or greater) at the output, or
when the amplifier is overheating.

4. JT Mode LED (Green). Lights when the JT switch is on or within 5 seconds after driving the amplifier in FM, AM or
JT mode with the JT Mode switch off.

5. TX LED (Red). Indicates the amplifier is keyed to TX (transmit).

6. AC Power On/Off Switch. (PS equipped models only.) Turns AC power on and off to the integrated power supply.

7. Power Switch. Puts the amplifier in the Ready-to-Key state. When off, the amplifier is bypassed.

8. JT Mode Switch. Puts the amplifier in JT mode. When in JT mode, the amplifier changes to near Class “C” opera­tion, running cooler and more efficiently for continuous duty modes.

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OVERVIEW

OVERVIEW

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REAR PANEL (shown with optional power supply)

9. Key Jack. Ground to transmit. The total keying current is under 10 mA.

10. RF In. 50-80W nominal, 100W max.

11. RF Out. It is strongly recommended that an external wattmeter be connected here. Use .405” or larger diameter,
50 ohm coaxial cable capable of handling full rated output power. RG-213, LMR-400 or similar cables are suitable.

12. Terminal Strip. Provides connections for fans, +13.6 VDC for powering external device and key out for external
relay and preamp switching.

1. +28VDC top cover fan voltage.

2. Fan voltage return.

3. External relay key return (48 VDC max.) used to key external, optional components.

4. +13.6 VDC @ 500 ma max for external relays and preamp.

5. Chassis ground.

13. External AC Power Cord. Included only on models equipped with integrated power supply. For models without
the power supply, 10 AWG power leads are supplied.

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OVERVIEW

THEORY OF OPERATION

The 6M-1K2 designation, indicates the amp works on the 6 meter Amateur Band and is capable of at least 1.25 kW of RF
output.

OVERVIEW

A single MRFE6VP61K25H Freescale™ LDMOSFET solid state device is the heart of the amplifier. Because most modern
Amateur transceivers have a 50 to 100W output on 6M, the gain of the device must be reduced 15 dB or less per part 97
FCC rules. The input level is dropped to 4 to 5 watts so the device is not overdriven as fatal damage will occur. In “bypass
mode” or with the Ready switch off and the green LED un lit, the input RF passes through an input relay and then through
a high power vacuum relay, through the internal SWR bridge and out to the antenna. When the Ready/power switch is
activated and the green LED is lit, the Amplifier can be keyed and when driven with the rated RF drive, will amplify to at
least 1200 Watts into 50 Ohms.

The Keying circuit requires a path to ground or near ground through the RCA connector on the rear of the amplifier. This is
usually accomplished by the transceiver but can also be keyed with a foot switch. A built in 15 to 20 millisecond delay al­lows the relays to close before a +2.8 VDC bias voltage is applied to the gates of the device.

When “keyed up”, with no drive applied to the device, it will idle at approximately 2 amps. This condition puts the device in
a class AB1 state. It is linear at this point so a drive of 5W will cause the amp to produce 100+Watts. On 6M, 100W of
drive, in SSB or CW mode will allow the amplifier to produce 1200 Watts minimum. If the drive power is continuous such as
with AM, FM or any JT mode, the amplifier will sense this continuous drive level and after about 5 seconds, the bias voltage
is reduced pulling the amplifier closer to class C. This reduces the drain current typically from 36 amps down to about 30
Amps and reduces the output slightly to 950 to 1050 Watt output.

When driven in the Single Sideband mode SSB or CW, the amplifier runs in the linear mode and delivers 1250W+peak to
the antenna. At full drive level the amp is at about the 1 dB compression point. Further drive will not cause much more
output, just more compression, possible distortion and less efficient operation.

A temperature sensor mounted next to the device, monitors the Celsius temperature of the huge copper “heat spreader”
the device is attached to. When the device temperature reaches about 40 degrees C, the two large but very quiet fans on
the top cover come on to push the warm air transferred to the aluminum fins out the rear of the amp. Another slightly
smaller, quiet bottom fan comes on and pushes cool outside air into and over the device and other RF components. This
warm air vents out the multiple rectangular openings at the rear of the main chassis. Over temperature occurs at 90 deg. C
and the amber LED will light. Cycling the READY switch re-sets the system.

A complete 1500W+ VSWR bridge is located just inside the RF output connector hear the rear panel. Forward and
reflected power is monitored and if the SWR reaches 2.5:1, the control system de-activates the amplifier and the AMBER
LED on the front panel will light. This “fault” condition can be “reset” easily by cycling the “Ready” switch or removing the
50 VDC powering the unit.

Operation in the fault condition is possible by turning off the ready switch and running in the “amp bypass” mode at the
drive level of your transceiver.

When 50 VDC enters the amplifier, it is split and one part passes through a 3 Amp fuse on the rear panel. this 50V DC is
sent to the regulator board and accompanying power dropping resistors for fans and two voltage regulators where 13.6
volts is produced for the control board functions and other relay operation. The 50 VDC is also sent through 0.005 ohm
resistor in the drain lead of the device. The voltage drop across the 0.005R is sensed and conditioned to provide a linear
voltage related directly to the device current in a 1/10 ratio. 10 Amps of drain current reads out as 1.00 volts and 30 Amps
of drain current reads out as 3.00 volts. This circuit allows accurate FACTORY ADJUSTMENT of Idle current, and
secondary bias control for JT, AM, or FM mode of operation.

The RF drive power from a transceiver enters through an “N” female connector on the rear panel and jumpers through a

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