PS Magazine - TB 43-PS-691

PS, The Preventative Maintenance Monthly

ISSUE 691

JUNE 2010
PS Magazine - TB 43-PS-691 - Page 23 of 33
42
PS 691
JUN 10
43
PS 691
Stuff Six
Your antenna comes with fve stakes, NSN 4030-01-073-6103—Four to use and one For
a spare. In sandy soil, Four stakes have proven not to do the job when the strong winds
blow. Use two stakes at each tiedown point instead oF one. Even then, you still may have
to use a dead man anchor, a rock anchor or a screw anchor to hold the antenna in place
like it says on Page 2-11 oF TM 11-5985-357-13.
OF course, iF you’re operating in cold weather with Frozen ground you might need to
use the cold weather stake, NSN 4030-00-187-5265. They’re slimmer and easier to drive in
the hard ground, but they also slip out easier when the ground thaws.
Stuff Four
The safety instructions in your TMs say to “clearly mark all guy wires and ropes with
the warning flags or signs supplied by your unit. Use strips of white cloth as warning
streamers.” That’s good info as far as it goes, but you might also consider using light
sticks, NSN 6260-01-230-8596, fastened with electrical tape to the wires for visibility at
night in heavily traf±cked areas. If you’re under blackout conditions, there are infrared
light sticks, NSN 6260-01-396-1710, that will do the job.
Stuff Five
Cable assembly CG-1889C/U, NSN
used
with
your
antenna is 80 Feet long. According to
your TM, you can cut it down to 50 Feet
as needed to remove damage, but no
Further. But, can you lengthen it?
Yes, you can by adding an additional
cable or two, but remember, each time
you lengthen it, you increase the db
attenuation and decrease the power to
reach the receivers you need to reach.
As is, your 80-Ft cable will get about
87 percent oF the signal strength to a
receiver. IF you double the length oF the
cable, it drops to about 58 percent. Can
you tolerate that kind oF power loss?
An alternative is to order the RG-213/U cable, NSN 6145-00-660-8711, by the Foot and
add only what you need to the original 80-Ft cable. This added length cable must have
connectors, NSN 5935-00-928-3127, installed on both ends to be usable.
IF you need to add an adapter to the cable to connect the
cable to the radio, order TRU-2064 adapter,
NSN 5935-01-375-5085. ±or a connector adapter
that will let you join cables,
OF course, the ideal is to select a site For
your antenna that will ensure the 80-Ft
cable provided reaches to your radio.
Stuff Three
±ig 2-8 oF the -13 gives instructions
on how to moisture-prooF mated R±
connectors. The TM recommends using
anti-corrosion silicone compound, NSN
6850-00-880-7616, on the threads and
then taping each connection with a
layer oF electrical tape, NSN 5970-00-419-
4291. That’s good advice, but to be really
eFFective at keeping moisture out oF joints
and connections, you need to use water-
displacing compound, NSN 6850-00-142-
9409, on the threads.
And, at the point where the cable
connects to the Feedcone, you need to use
a good coaxial cable connector sealant
to keep moisture out! Electrical tape
at this juncture dries in the sun, shrinks
and wears out. Coaxial cable connector
sealant (bought at your local electronics or
automotive store) seems to last Forever and
once removed, the area looks like new.
Add sealant to keep out moisture!
Light at night!
You’ve got 80 Feet oF cable
No matter the length of the
cable, it should be protected
from vehicles and people with
boards laid on both sides of it
that are thicker than the cable.
691.42-43.indd
1-2
5/3/10
2:18:18 PM
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