11
The
HX851
has been carefully aligned at the factory for
the specified performance across the VHF Marine band.
Realignment should therefore not be necessary except in
the event of a component failure.
All component replacement and service should be per-
formed only by an authorized STANDARD HORIZON
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 compo-
nent has been replaced.
We recommend that servicing be performed only by au-
thorized STANDARD HORIZON 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
STANDARD HORIZON service technicians realign all
circuits and make complete performance checks to en-
sure compliance with factory specifications after replac-
ing any faulty components. Those who do undertake any
of the following alignments are cautioned to proceed at
their own risk.
Problems caused by unauthorized attempts at realign-
ment are not covered by the warranty policy. Also,
STANDARD HORIZON must reserve the right to change
circuits and alignment procedures in the interest of im-
proved performance, without notifying owners. Under
no circumstances should any alignment be attempted
unless the normal function and operation of the trans-
ceiver are clearly understood, the cause of the malfunc-
tion has been clearly pinpointed and any faulty compo-
nents replaced, and the need for realignment determined
to be absolutely necessary. The following test equipment
(and thorough familiarity with its correct use) is neces-
sary for complete realignment. Correction of problems
caused by misalignment resulting from use of improper
test equipment is not covered under the warranty poli-
cy. 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. Do not attempt to perform only a single step un-
less 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 presented.
Required Test Equipment
RF Signal Generator with calibrated output level at
200 MHz
Deviation Meter (linear detector)
AF Millivoltmeter
SINAD Meter
Inline Wattmeter with 5% accuracy at 200 MHz
Regulated DC Power Supply: adjustable from 6 to
10 VDC, 2A
50-ohm Non-reactive Dummy Load: 10W at 200 MHz
Frequency Counter: >0.1 ppm accuracy at 200 MHz
AF Signal Generator
DC Voltmeter: high impedance
VHF Sampling Coupler
AF Dummy Load: 8 ohm, 2W
Oscilloscope
Spectrum Analyzer
IBM
®
PC/compatible computer with Microsoft
®
Win-
dows
®
2000, XP, or Vista
Standard Horizon HX851 Alignment Program and
Alignment Jig.
Alignment Preparation & Precautions
A dummy load and inline wattmeter must be connected
to the main antenna jack in all procedures that call for
transmission, except where specified otherwise. Correct
alignment is not possible with an antenna. After com-
pleting one step, read the following step to determine
whether the same test equipment will be required. If not,
remove the test equipment (except dummy load and watt-
meter, 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 be-
tween 20 and 30 °C (68 ~ 86 °F). When the transceiver is
brought into the shop from hot or cold air it should be
allowed some time for thermal equalization with the
environment before alignment. If possible, alignments
should be made with oscillator 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 this procedure
are based on 0 dBµ = 0.5 µV(closed circuit).
Alignment
