Alignment

Introduction

The VX-900is carefully aligned at the factory for

the specified performance across the frequency

range specified for each version. Realignment

should therefore not be necessary except in the event

of a component failure, or when altering the ver-

sion type. All component replacement and service

should be performed only by an authorized VER-

TEX STANDARD representative, or the warranty

policy may be voided.

The following procedures cover the sometimes criti-

cal and tedious adjustments that are not normally

required once the transceiver has left the factory.

However, if damage occurs and some parts subse-

quently are placed, realignment may be required. If

a sudden problem occurs during normal operation,

it is likely due to component failure; realignment

should not be done until after the faulty component

has been replaced.

We recommend that servicing be performed only by authorized VERTEX STANDARD service techni-

cians who are experienced with the circuitry and

fully equipped for repair and alignment. Those who

do undertake any of the following alignments are

cautioned to proceed at their own risk. Problems

caused by unauthorized attempts at realignment are not covered by the warranty policy. Also, VERTEX STANDARD reserves the right to change circuits and

alignment procedures, in the interest of improved

performance, without notifying owners.

Under no circumstances should any alignment be

attempted unless the normal function and opera-

tion of the transceiver are clearly understood, the

cause of the malfunction has been clearly pinpointed

and any faulty components replaced, and realign-

ment determined to be absolutely necessary.

Do not attempt to perform only a single step unless

it is clearly isolated electrically from all other steps.

Have all test equipment ready before beginning, and

follow all of the steps in a section in the order pre-

sented.

The following test equipment (and thorough famil-

iarity with its correct use) is necessary for complete

realignment. Correction of problems caused by mis-

alignment resulting from use of improper test equip-

ment is not covered under the warranty policy. While

most steps do not require all of the equipment listed,

the interactions of some adjustments may require

that more complex adjustments be performed after-

wards.

Required Test Equipment

rRF Signal Generator with calibrated output level at 600 MHz

rDeviation Meter (linear detector)

rIn-line Wattmeter with 5% accuracy at 600 MHz

r50-Ohm RF Dummy Load with power rating 10W at 600 MHz

r16-Ohm AF Dummy Load

(Attention : Audio output is BTL output; do not

short "shield" to ground!)

rRegulated DC Power Supply (standard 7.5V DC, 3A)

rFrequency Counter with 0.2 ppm accuracy at 600 MHz

rAC Voltmeter

rDC Voltmeter

rUHF Sampling Coupler

rIBM PC / compatible Computer with Microsoft DOS v3.0 or later operating system

rVertex Standard CT-71Connection Cable and SVC39 Alignment program

Alignment Preparation and Precautions

A50-Ohm RF Dummy Load and in-line wattmeter

must be connected to the main antenna jack in all

procedures that call for transmission, except where

specified otherwise. Correct alignment is not pos-

sible with an antenna.

After completing one step, read the following step

to determine whether the same test equipment will

be required. If not, remove the test equipment (ex-

cept dummy load and wattmeter, in connected) be-

fore proceeding.

Correct alignment requires that the ambient tem-

perature be the same as that of the transceiver and

test equipment, and that this temperature be held

constant between 20° and 30° C (68 ° ~ 86 ° F). When

the transceiver is brought into the shop from hot or

cold air, it should be allowed time to come to room

temperature before alignment.

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