Click here to make tpub.com your Home Page

Page Title: Section II. TESTING PROCEDURES
Back | Up | Next

Click here for thousands of PDF manuals

Google


Web
www.tpub.com

Home

   
Information Categories
.... Administration
Advancement
Aerographer
Automotive
Aviation
Construction
Diving
Draftsman
Engineering
Electronics
Food and Cooking
Logistics
Math
Medical
Music
Nuclear Fundamentals
Photography
Religion
   
   

 



TM 11-5820-695-35
d. Coating Cure, Circuit Side.
(5) Check the thickness of the coating using a
(1) Place board into an air circulating oven
wet gage.  A  total buildup of .006 t.0025 inches is
with the coating side up.
adequate.
(2) Follow the baking and curing time periods
(6) Place board (coated side up) on a clean
for the various materials as indicated in the chart below.
air bench for a period of 2 hours thereby insuring that all
thinning solvents have been vaporized and carried off.
Mfr.
Baking time
Curing time
Hysol Corp.
4 hrs. at 148F
Same, plus 2 days at room
temp.
PC-26M
PC-29M
3 hrs. At 150F
Same, plus 2 days at room
temp.
CONAP Inc.
3 hrs. At 138F
Same, plus 2 days at room
temp.
Essex Chemical
3 hrs. At 150F
Same, plus 2 days at room
temp.
e.  Conformal Coating Application, Component Side.
component side.  Follow the curing time periods for
materials used in accordance with the chart ind above.
Follow steps described under c above, to coat
Section II. TESTING PROCEDURES
generator (via the elbow adapters).  When a load
4-14. General
impedance terminating a, coaxial cable matches the
cable characteristic impedance, no wave will be
Testing is limited to verifying the quality of rigid coaxial
reflected and the oscilloscope will display only the
cables used in Transmitter, Radio T1054/GRC-144 and
indicent voltage propagated down the cable.  If a
Receiver, Radio R-1467/ GRC-144.
mismatch exists, part of the incident wave is reflected.
The reflected voltage wave will appear on the
4-15. Equipment Required
oscilloscope display algebraically added to the incident
wave. These waveforms are illustrated in views A and
Equipment required for testing is listed below.
a. Time Domain Reflectometer Plug-in HP1415A.
b. Oscilloscope HP-140A.
c.
The quality criteria for the rigid coaxial cable
c. Calibrated Mismatch 1.10 VSWR Mecca Model
used in the T-1054/GRC-144 and R1467/GRC-
400-1.10.
144 is a VSWR of 1.1 maximum. This can be
d. Adapter GR874-TO-Type N General Radio 874
measured using the reflectometer as follows:
GNP.
e. 60 ohm Termination, HP908A.
f. Elbow Adapter General Radio GR874 (two
required).
g. Adapter,  GR874B-to-SMJ  OMNI
Spectra
21210.
h. Adapter, UG-29B/U N female-o-N female.
4-16. Coaxial Cable Test
a. Coaxial cable assemblies are tested using
Oscilloscope HP-140A with Time Domain Reflectometer
Plug-in HP-441&A.  The reflectometer incorporates a
step generator which produces a positive-going incident
wave which is fed into the coaxial cable undergoing test.
The incident and reflected waveforms are then analyzed
to determine if 'there is a mismatch or if there are any
Figure 4-5. Reflectometer test waveforms.
discontinuities along the cable.
b. The oscilloscope high impedance input bridges
the cable at its junction with the reflectometer step
4-9


Privacy Statement - Press Release - Copyright Information. - Contact Us

Integrated Publishing, Inc. - A (SDVOSB) Service Disabled Veteran Owned Small Business