MaxAmp 11/45 Manual and Schematic

8/18/2019 MaxAmp 11/45 Manual and Schematic

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Welcome

Kantronics would like to take this opportunity to thank you for purchasing the Max-Amp

1

or

Max-Amp 45. Each Max-Amp adds the function o radio frequency (rf) power amplification to

your station. We take ptide in offeting these latest designs - our sixth generation, and hope that

your Max-Amp will provide you with many hours o enjoyment.

What You Can Do With The Max Amp?

By combining the Max-Amp with your VHF (2-meter) transmitter-receiver (transceiver) for

portable, mobile, or base station use, you ll be able to reach stations that might not otherwise be

able to communicate with you.

• You be able to boost your station transmit power - i need be - when in emote area

or when another station can t hear you. Simply power the amplifier by pushing the

POWER switch and it will then key automatically whenever you key your VHF

transceiver.

• You ll be able to boost received signals. You can boost the level o received signals

when you use the pre-amp.


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First Things First

Please take a moment to deal with these few preliminary topics.

Warranty Registration Return/Repair Policies

This is a good time to read and be sure you understand and accept the warranty

registration and return/repair policies printed in the appendix.

By

completing and

returning your warranty registration and sales receipt now, you can be sure that we have the

necessa1y information ·in case you need to use your limited

wa nnty

coverage.

Package Contents

Check to see that you have the items listed below (later

you

will see how t4ese items are used in

your station):

• Max-Amp unit (with 6 power leads attached)

• Wa1rnnty sheet (see front inside manual)

• This manual

Additional Parts You ll Need (not provided)


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Equipment Specifications and Panels

The table below lists the specifications for your Max-Amp. The following page desclibes the

layout and function of the front and back panels.

Unit

Max Amp 10 Max Amp 45

Frequency Range

144-148 MHZ

144-148 MHZ

Maximum Input

10 Watts 45 Watts

Power

Input Range

5 to 10 Watts 5 to 45 Watts

Output

150

W@

10 in 75 Watts@ 10 in

150 Watts @45

in

Max temperature

50° 50°

Receive Preamp 15dB 15dB

Keying

Automatic-RF sensing

Automatic-RF sensing

Input-Output Impedance 50 Ohms . 50 Ohms


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Max Amp Front Panel

The front panel contains three switches and four LEDs. Push in the left-most switch (Power) to

apply power to the amplifier. Press in the Preamp switch to apply power to the receive signal

preamplifier. Press in the single sideboard (SSB) switch to add a drop-out delay in keying for

SSB operation.

Any combination of switches may be pushed in at any time.

f

a transceiver is attached and

keyed while the Preamp switch is pressed in, the preamp circuit will be switched out

of

the RF

path automatically, thus protecting this receiving circuit.

When the Power switch in pressed in, the left-most LED (PWR) will be lighted and supply

voltage will be applied to the control and bias circuitry. Please note that power is applied to the

collectors

of

the power transistors whenever the power leads are attached to a supply.

When the Preamp switch is pressed in, the PRE LED will be lighted, and when the Max-Amp is

keyed, the transmit (TX) LED will glow.

The TEMP LED will light and keying of the amplifier is disabled when the amplifier is too hot

to operate safely. The transmitter power will be bypassed through the amplifier in this

condition. The LED will go off and keying will automatically be enabled when the unit has

cooled enough to allow safe operation.


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Installing the Max Amp

The Max-Amp is installed between your radio transceiver and the antenna.

Power

Attach the 12 gauge red and black leads coming from the rear panel of the unit to

a+

13.8

VDC, 30 ampere power supply, red lead to the plus terminal and black lead to the ground

terminal.

f

your installation requires that the unit be more than six feet from the supply, cut the

red and black leads near the unit and splice in

8 gauge or 10 (AWG) wire.

note: The amp comes with spade connectors attached to the power leads. These were used for

production testing. It s your option to remove them and use something else to attach the leads to

a power supply.

Antenna

Connect the coaxial lead from your antenna to the terminal marked 'ANT'

(S0-239

type that

mates with a

PL-259 type) on the back of the unit. f you prefer to use N-type connectors, the

bulk-head type will fit exactly in place of the VHF connectors that come standard with the unit.

To change to the N-type, you'll have to de-solder the center pin

of

the 'TX' and 'ANT' connectors


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How To Operate the Max Amp

With your Max-Amp installed in your station, press the POWER switch to enable the radio

frequency power amplifier. When you key your transceiver, the amplifier will key automatically,

assuming you have applied at least 5 watts. Please do not exceed 1 watts input for the Max

Amp

1

or

45

watts in for the Max-Amp 45. When the amplifier is keyed, the red TX LED will

light on the front panel. When you release the push-to-talk key on your transceiver, the red TX

LED should go out.

Press the Preamp switch to enable the receive preamplifier. f you once again key your

transceiver, the preamp will be switched out

of

the RF power path automatically; you do not

have to disable it before transmitting.

f our Relays Chatter

f he relays chatter when you key your transceiver, this is an indication that you have not

applied sufficient power to the Max-Amp or that your antenna is mismatched ( does not present

50 ohms to the amplifier.)

Caution: Do not operate the amp as a repeater amp. And,

do

not exceed an operating duration

of

SO

on average, i.e. talk no more than SO

of

he time on average - over several minutes.


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Appendix

How the Circuit Works

The Max-Amp

10

and Max-Amp 45 are identical except for a pre-power amplifier section found

in the Max-Amp

IO.

This pre-power amp boosts input power from 5 to

IO

watts up to 40 to

45

and the push-pull finals - found also in the MaX; Amp 45 - finish boosting the power to 150 watts

(for full rated input power). Both amplifiers consist of five circuit sections: the micro-strip and

relays paths (for the RF signal), the input and output directional coupler and control circuits, the

receive signal pre-amplifier, and the power amplifier(s).

DC circuits. 13.8 VDC is applied to the power transistors and power switches at all times.

Pressing either the PWR switch or the PREAMP switch applies power to

t :e

relay control

circuitry at the summing point ofD5 and D6 (bottom left of the schematic). The resulting

voltage ("VCC") is then applied to the 5 volt regulator, the temperature sensor, and VCC

ofU

and U3 (the control ICs).

With the PWR switch pressed in, the amplifier will be keyed when 5 watts or more are applied

to its input (marked as

TX

on back). Assuming the receive pre-amp is off and the PWR switch is

off, power applied to the amp will flow through input relay RL4, through preamp relays RL3B

and RL3C, and out the amp to the antenna via RL5C (unamplified) . When the PWR switch is


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I

Both relays are also turned off if the Max-Amp gets too hot (thermal shutdown). Comparator

U3D is set to tum on, shutting down the amp, ifthe temperature sensor, TSl, sees 50 degrees

C

Note, however, that the receive relay is keyed separately, still, by ahy input power that may be

applied to the amp, thus protecting the preamp if it is still on.

Amplification is essentially linear.as long as the amplifier is not overdriven, i.e driven below the

maximum input as per the specifications. Note that the power stage, consisting ofQ6 and Q7 is

push-pull. The pre-power amp, while single-ended, is essentially linear when biased as long as

the max input power of 10 watts is not exceeded.

How to Modify Transmit Delay for SSB Operation

-

You may wish to increase the delay in drop-out keying if you plan to use the amplifier for single-

sideband (SSB). The time delay, as shipped from the factory, is set at about one second by C9

and RI 5 To increase the drop-out delay, the delay after unkeying, increase RI 5 We will not

void the warranty if you wish to drill a hole in the front panel to add a pot.

f

you do add a pot

instead of a single resistor, keep the leads as short as possible to prevent rf coupling.

Please note that Rl5 is located near the SSB switch on the pcb.


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How to Measure M Power

Accurate measurement

of

VHF power amplifier output is easy, given proper equipment and

setup. However, many amp users aren't familiar with the requirements for accurately measuring

an amp s output. Before you call your dealer or the factory to report greater-than-expected

power output or low power output, check out the test arrangement outlined below, and see if

you meet all the measurement guidelines listed.

What

You

Will Need

A good equipment arrangement for measuring power pe1formance

of

a 2-meter amplifier is

pictured below. To accurately determine

an

amplifier's power output, we recommend

measuring both the input and the output with two high-quality wattmeters, such as the Bird 43

Thruline. You ll also need an FM transceiver to drive the unit under test (UUT) and a good

dummy load made for 2-meters to terminate the output of the amplifier. finally, you ll need a

2 V de power supply and heavy cabling capable

of

meeting the voltage and current specs of

the amplifier.

Measuring the

Output

Apply de power to your FM transceivers, and the UUT, key the transceivers mic, and measure

the voltage

at

the supply terminals of the UUT.

f

he voltage is near 13.8 Vdc, then proceed.

Key the mic again and observe amp input and output power. f values are close to those


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Power Measurement uidelines

f

you can answer "Yes" to all

of

the following measurement guidelines below, then power

measurement is probably correct.

f

you cannot answer "Yes," then it is very likely that your

power measurements are inaccurate.

• Are you using quality meters designed for the frequency and power levels

involved? Bird model

43

meters with slugs of the appropriate frequency and

power level would be ideal. Poor quality VSWR meters, such as those designed

for CB or HF use, are not adequate. Most "inexpensive" meters will not do the

job.

Don t

count on do-all multi-band meters.

• Are you using a dummy load, and is it appropriate for the power level and

frequency? Oil-can dummy loads, even if spec d for VHF, are generally not

suitable for VHF and UHF. Wire-wound dum rlly loads are.also unsuitable.

Although high power power dummy loads that present

50

ohms to the amplifier

are expensive, there really is no good substitute.

• Are you using your antenna as the test load, and does it present 50-ohms

of

pure

resistance to the amp? Antenna impedance is rarely resistive but has a reactive

component at the frequency of operation. To check the reactance, remove the

UUT and see if your rig can deliver full power to your antenna, and reverse the

slug in the wattmeter to check for reflections. A reflection indicates that the


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• Does your transceiver deliver full power when driving the UUT? Most modern

transceiver are designed to reduce power i they detect a load other that 50

ohms.

Reduced

rig

output will,

o

course, reduce power

amp

output.

f

your rig isn t

producing full power, check for power being reflected from the amp to the

rig.

Do this by reversing the slug

in

the input wattmeter

and

check

for

reflected

power. t

is

possible that the amp s input circuit tuning may need to be touched

up.

While it is generally easier to make accurate measurements at HF it

is

possible to measure true

power

at VHF or UHF using

the

proper equipment. A good dummy load quality meters, and

high quality cable

o

the appropriate

size

will

contribute to accurate power measurements

at

VHF and UHF.


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imited Warranty

KANTRONICS

CO.,

INC.

LI1\1ITED

WARRANTY

EffectiveJanuaiy

1,

1997

To receive notice of future updates, new product info1mation, and prompt warranty service,

please fill in the Kantronics/rfconcepts

Wa11 anty

Registration form

COMPLETELY

and return

it along with a copy of

proof

of

purchase (to establish purchase date) to Kantronics Co., Inc.,

1202 East 23rd Street, Lawrence, KS 66046 USA. (You'll find the wa1Tanty card inside the

front of this manual).

NOTE:

Return

of

the Warranty Registration

Card and

proof

of purchase is a pre-

condition

to

warranty coverage.

1.

WARRANTY.

Kantronics Co., Inc., ( Kantronics ) warrants to the first consumer purchaser

( you ), for the Applicable Warranty Period (as described below), that the Applicable Product

(as described below) will be free from defects in mate1ial and workmanship.

2.

REMEDY.

Kantronics agrees that, for any Applicable Product found by Kantronics to be in


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LIMITATIONS ON

OW

LONG AN IMPLIED WARRANTY LASTS SO THE ABOVE

LIMITATION MAY NOT APPLY TO YOU.

5. APPLICABLE PRODUCTS AND PERIODS.

Kantronics products are of two types - (1)

hardware units and (2) firmware and software for operation of these units, whether incorporated

into the units themselves or separate from the as adjuncts or accessories to the units. Hardware

units and the media containing fomware, software and documentation are sold to the consumer

purchaser and become property of the purchaser. Firmware and software are licensed for use by

the consumer purchaser in return for a fee included in the purchase price of the units and do not

become the property of the consumer. (See separate License Agreement provided with these

products). The products to which the warranty

of

Section hereof applies (herein Applicable

Products ) and the pe1iods during which the warranty shall apply to such products (herein,

Applicable Warranty Period ) are as follows:

Applicable Products:

UNITS:

KPC-9612, KPC-9612 PLUS, KAM, KAM Plus, KPC-3, KPC-3 PLUS, rfc 2/70, rfc 2-70G, rfc

4-310, Mini-Amp 144, Mini-Amp 144P, Mini-Amp 440, Mini-Amp 440P, MAX-Amp 10,

MAX Amp45.

Applicable \Varranty Period:

One (1) year from date of purchase.


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shipping whether or not caused

by

poor packaging), neglect, accident, wiring not installed by

Kantronics, improper parameter settings which are cleared by performing a hard reset, or use in

violation of instmctions furnished by Kantronics or of generally accepted indust1y practice.

Kantronics does not warrant that the functions contained in any software will meet your

requirements

or

achieve your intended results; or that operation of any software will by ·

unintenupted

or

elTor-free

or

without effect upon other software used with it. Responsibility

or

the selection o he hardware and software program t achieve your intended results rests with

you

7. REMEDY PROCEDURE. Should you need to make a wa1Tanty claim, first contact the

dealer from

whom

you purchased the product. f he dealer is unable to assist you, contact

Kantronics., Inc.,

by

mail at 1202 East 23rd Street, Lawrence, Kansas 66046 USA;

by

fax at

913-842-2021; or by

phone

at our Customer

Suppmt

number 913-842-4476 Hours 9:00 a.m.

noon and 2:00 p.m.- 5:00 p.m. CST). Contact us prior to returning an Applicable Product to

receive a Return Authorization Number. As a practical matter, problems often be solved in

such a manner without the product having to be returned to Kantronics for repair or

replacement.)

Return

of

any Applicable Product for the enforcement

of

rights under this Limited Warranty

shall be at your expense.

Any

product returned for watTanty service which Kantronics

determines to be without defect or not covered by thi s Limited Warranty shall be subject to a

minimum charge of

one half hour

labor rate and the product will be returned to you at your

sol

e

expense. Please note, no warranty service will be provided until Kantronics has been furni shed


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Return/Repair Procedures

Problems?

Important: Our repair statistics show that

over 70 percent of the units returned for

service

do

not, in fact, require any service.

Therefore, we advise you to please double

check the following list of common, user

solvable, sources

of

difficulty before

contacting Kantronics about returning your

unit for service.

f

you have a real problem, we want to get it fixed. Perhaps the following experiences/advice

may eliminate your need to return the unit. Good luck

I'm not getting any power out

o

the amp


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drive to the

amp

from the transceiver. Check the cabling, power supply and fuse first. f he

relay(s) buzz, replace one or more

of

the ICs, starting with U2, the 4001. These are available at

Radio Shack.

I'm not getting enough

power out

of the amp

Please read the

How

to Measure Power" article in this appendix. Can you say "yes" to all the

measurement guidelines?

We

find that the most common problem here is that the amp is doing

fine but the user is tcying to use a meter that was not designed (or designed properly) for VHF

FM use. Cheap CB VSWR meters are not adequate for 2-meter use.

The second most common problem is that the power supply is not delivering sufficient DC

power to the amp. You will not get full rated output power if you cannot measure 13.8 volts

or

close to it at the terminals of the amplifier, not at the terminals of the power supply. And, your

supply may not

be

delivering sufficient current. These amps require a bunch

of

current, in the

order of20 amperes.

f

you're using one supply, make sure it has enough current capacity for

both the

amp and

the transceiver.

Also,

if you have spliced long wires onto the power leads of the amp, it should be heavy wire,

say# 8

or#

10, so that a large voltage drop does not occur between the power supply and the

amp. For example

if

you used #16,

you'll

get a big voltage drop with 20 amperes

of

current and


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Service

The Service Depaitment telephone hours are

m

- noon and 2

pm

-

5

pm

Central Time, Monday

through F1iday. f you call outside these hours, the phone will just iing. The service department

telephone is not connected to the main switchboard and the switchboard receptionist cannot

transfer you to the service number. f ines are busy, you may wish to (and it may be faster to)

contact service by letter, fax, or e-mail. Service e-mail is cun-ently checked twice per day. Before

contacting us, please take the time to list out your problem fully and carefully. Here are the

contact numbers:

Kantronics Co., Inc.,

1202 E. 23rd Street

Lawrence, KS 66046

service phone line: 913-842-4476

service fax line: 913-842-2021

service e-mail address: [email protected]

website address: www.kantronics.com

When w1iting , faxing, or e-mailing Kantronics, include a clear desc1iption of the problem, and

unit name. Be sure to include a return fax number and/or e-mail address.


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International Returns

This section applies to international returns only, not to domestic returns.

In case of unit problems, first contact the dealer from whom you purchased the product. f you

must return Kantronics product to us, please observe the steps outlined below. It will save both

you, the customer, and Kantronics unnecessary difficulties and expense.

• All returns must be shipped to the factory at 1202 East 23rd Street, Lawrence, KS

66046 U.S.A.

• All expenses ofreturning item(s) to Kantronics must be paid by you including

any duty/entry fees, whether the return is for warranty or nor:i-warranty repair.

• Usually, the best way to return item(s) to us is by mail. However,

if

you wish to

use one

of

the courier services such

as

DHL, UPS Expedited, Federal Express,

etc. be sure to use

DOOR TO DOOR

service.

f

you use one

of

these services,

a commercial invoice may be required. Please check with your carrier before

shipping. Include in the descliption of the item(s) on the pape1work (whether

postal or comier) the words:


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• brief desc1iption

of

the problem

• reference to any conversations with the technical/sales staff about the problem

• For

wa1Tanty

repairs, we will pay the shipping charges to return the item(s) to you

via air parcel post.

f

you wish return by courier service, include your account

number. To e eligible for repair under warranty, we must have record that you

sent your Warranty Registration fo1m and proof

of

purchase to Kantronics, and

the item(s) must still be within the warranty pe1iod at the time the return is

authorized.

• For non-wall anty repairs, you must pay the return shipping charges.


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MaxAmp 11/45 Manual and Schematic

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