Vertex Standard VX-7R Bedienungsanleitung PDF herunterladen (Seite 11)

Alignment

Introduction and Precautions

The VX-7R has been carefully aligned at the factory for

the specified performance across the specified amateur

bands. Realignment should therefore not be necessary

except in the event of a component failure. All compo-

nent replacement and service should be performed only

by an authorized VERTEX STANDARD representative,

or the warranty policy may be voided.

The following procedures cover the sometimes critical

and tedious adjustments that are not normally required

once the transceiver has left the factory. However, if dam-

age occurs and some parts are replaced, realignment may

be required. If a sudden problem occurs during normal

operation, it is likely due to component failure; realign-

ment should not be done until after the faulty component

has been replaced.

We recommend that servicing be performed only by

authorized VERTEX STANDARD service technicians,

who are experienced with the circuitry and fully equipped

for repair and alignment. Therefore, if a fault is suspect-

ed, contact the dealer from whom the transceiver was

purchased for instructions regarding repair. Authorized

VERTEX STANDARD service technicians realign all cir-

cuits and make complete performance checks to ensure

compliance with factory specifications after replacing any

faulty components.

Those who do undertake any of the following align-

ments are cautioned to proceed at their own risk. Prob-

lems caused by unauthorized attempts at realignment are

not covered by the warranty policy. Also, VERTEX STAN-

DARD must reserve the right to change circuits and align-

ment procedures in the interest of improved performance,

without notifying owners.

Under no circumstances should any alignment be at-

tempted unless the normal function and operation of the

transceiver are clearly understood, the cause of the mal-

function has been clearly pinpointed and any faulty com-

ponents replaced, and the need for realignment deter-

mined to be absolutely necessary.

Required Test Equipment

H RF Signal Generator with calibrated output level at 500 MHz

H Deviation Meter (linear detector)

H In-line Wattmeter with 5% accuracy at 500 MHz

H 50-ohm, 10-W RF Dummy Load

H 8-ohm AF Dummy Load

H Regulated DC Power Supply adjustable from 3 to 15 V DC, 3A

H Frequency Counter: 0.2-ppm accuracy at 500 MHz

H AF Signal Generator

H AC Voltmeter

H DC Voltmeter: high impedance

H UHF Sampling Coupler

H SINAD Meter

Alignment Preparation & Precautions

A 10-W RF dummy load and in-line wattmeter must be

connected to the main antenna jack in all procedures that

call for transmission, alignment is not possible with an

antenna. After completing one step, read the next step to

see if the same test equipment is required. If not, remove

the test equipment (except dummy load and wattmeter,

if connected) before proceeding.

Correct alignment requires that the ambient tempera-

ture be the same as that of the transceiver and test equip-

ment, and that this temperature be held constant between

68~86°F (20~30°C). When the transceiver is brought into

the shop from hot or cold air, it should be allowed some

time to come to room temperature before alignment.

Whenever possible, alignments should be made with os-

cillator shields and circuit boards firmly affixed in place.

Also, the test equipment must be thoroughly warmed up

before beginning.

Note: Signal levels in dB referred to in the alignment procedure

are based on 0 dBµ=0.5 µV (closed circuit).

Alignment Setup

Wattmeter

In-Line

RF Load

50-ohm

Coupler

Sampling

Meter

Deviation

Counter

Frequency

Generator

RF Signal

Meter

SINAD

AF Load

8-ohm

1 2 ... 6 7 8 9 10 11 12 13 14 15 16 ... 63 64

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