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this man ual for pin lay out di agram.
While mon i tor ing 121.5 MHz on an AM
re ceiver, and with the unit switch in the
“OFF” (down) po sition, ac tivate the ELT
by us ing a rapid for ward (throw ing) mo -
tion, in the di rection of the ar row, fol -
lowed by a rapid re vers ing ac tion. Ver ify
ac ti va tion via the au ral swept tone on the
re ceiver. Fol lowing ac tivation, “RE SET”
the unit by tog gling the “ON/OFF” switch
to “ON” then back to “OFF”.
4.3.6 (Step 5a) Elec tri cal Check
Activate the ELT. As the unit will be on
for three min utes it is rec om mended that
it be placed in a con tainer ca pa ble of
sub stan tially at tenuating RF sig nals. Re -
mem ber that all tests must be per formed
within the first five min utes af ter the hour
UTC (Uni ver sal Co or di nated Time). Mon i -
tor the fol lowing per formance cri te ria for
three min utes (power out put must be
made at the end of the three min ute pe -
riod). En sure that ad e quate at ten u a tion
rated for 406.028 MHz, 5 Watts is in -
stalled be tween the ELT’s 121.5/243/406
MHz out put and the in put to mea sure -
ment equipment to pre vent dam ag ing the
in put cir cuitry.
4.3.7 (Step 5b) 121.5/243 MHz
Power Out put
Connect the equip ment as shown be low:
ARTEX AIRCRAFT SUPPLIES DOCUMENT # 570-5060
03/22/04 PAGE 4-5
Note: use a fresh bat tery pack (12.5 volts
nominal) or a 4 amp, 12.5 vdc power
sup ply as power source.
The test equip ment spec i fied in the fol -
lowing steps is only a rec ommendation.
The use of other man u fac turer’s mod els
of test equip ment ca pa ble of pro vid ing
equivalent mea surement re sults is ac cept -
able.
Set the Spec trum An alyzer as fol lows:
· Center Freq: 121.5MHz
· Span: 1 MHz
· Resolution Band width: 1 MHz (min)
· Ver ti cal Dis play: 10 dB/Div
· Sweep: Auto
· Peak/Avg: Peak
· Reference Level: 30 dBm
· Time/Div: 20ms
Ad just the ref er ence am pli tude to place
the peak of the car rier slightly above the
top graticule line.
Enable the “fine” am plitude ad justment.
Set the car rier peak to ex actly the top of
the ref erence line.
Read the dis played am pli tude.
Re peat for the 243.0 MHz har monic
(Change the “Cen ter Fre quency” to 243.0
MHz. All other set tings re main the same).
The min i mum al lowed am plitude on
121.5 MHz and 243.0 MHz is 23 dBm
(200 mW).
4.3.8 (Step 5c) 121.5 MHz Fre -
quency
The ELT trans mit ter fre quency may be
mea sured as fol lows us ing the fre quency
coun ter func tion of the spec trum analyzer:
Connect as shown be low:
If the 121.5 MHz car rier fre quency is
within spec i fied pa ram e ters, the 243.0
MHz fre quency will also be within spec i -
fied pa ram e ters. (Note: If us ing a fre -
quency coun ter alone, the use of a
demodulator or “di ode de tector” is
required.)
The ELT should be within 50 ppm (+/-
6.075KHz) of 121.500000 MHz.
4.3.9 (Step 5d) Au dio Mod ula -
tion
During the swept tone por tions the au -
dio should “sound” like an ELT. Set the
unit switch to the “OFF” po si tion.
4.3.10 (Step 5e) Mea sure
406.028 MHz Power
Note: the power out put is ap prox i mately
37 dBm (5 Watts). En sure ad equate at -
ten u a tion is in serted in-line be tween the
ELT’s 406.028 MHz out put and the in put
to the spec trum an alyzer to pro tect the
an a lyzer’s in put cir cuitry.
Connect the equip ment as shown be low:
Set the Spec trum An a lyzer as fol lows:
ARTEX AIRCRAFT SUPPLIES DOCUMENT # 570-5060
03/22/04 PAGE 4-6
Applicable
Attenuator
Spectrum
Analyzer
ELT
BNC
CONNECTOR
ELT
BNC
CONNECTOR
Applicable
Attenuator
SPECTRUM
ANALYZER
· Center Freq: 406.028 MHz
· Span: 1 MHz
· Resolution Band width: 1 MHz
· Ver ti cal Dis play: 10dB/Div
· Sweep: Auto
· Peak/Avg: Peak
· Reference Level : 30 dBm
· Time/Div: 20ms
· Max Hold: On
· Attenuator (as re quired) on In put
Turn the ELT on and wait approximately
50 sec onds for the 406.028 MHz
transmitter to turn on (trans mit ter sends
out first sig nal at 50 sec onds then ev ery
50 sec onds there af ter). De ter mine the
power out put from the stored wave form.
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DESCRIP TION, OPERATION, INSTALLATION AND MAINTENANCE MANUAL(18)
