Tas Coaxial Cable Fabrication - Honeywell BENDIX KING KMH 880 System Installation Manual

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2.2.7 TAS Coaxial Cable Fabrication

The TAS cables must have an attenuation of 2.0 ± 1.0 dB within the frequency band of
1030-1090 MHZ. To ensure proper phase matching, each of the four cables of a set must
be of the same type. The lengths in each set of four must be within 2.0" of each other.
Color bands on the cable ends to match the antenna color bands is suggested as an aid
to hook up. Cables can be fabricated or purchased from a cable vendor.
The nominal length of each set of four cables should be recorded for the
particular installation in the event a cable should require replacement. If
rework is required, a cable may be cut a maximum of 6".
The following defines the characteristics of the 50 ohm coaxial cable types that can be
used with the KA 815 Antenna. Connectors are also defined. All lengths are defined as
end to end. Any in-line or bulkhead penetrations must be evaluated separately. It is rec-
ommended that the installer purchase prefabricated cable assemblies when using in-line
or bulkhead disconnects. Prefabricated cables can be purchased from Pic Wire & Cable
or ECS. These vendors have expertise in providing the aviation industry reliable cable
assemblies that meet the requirements for the various collision avoidance systems. It is
the installing agency's responsibility to show airworthiness of the fabricated cable assem-
blies.
When determining cable type and length make the following assumptions.
A. Attenuation of each straight TNC male connector is 0.06 dB @ 1GHz
(using a 030-00134-0000 RF Connector)
B. Attenuation of each right angle TNC male connector is 0.07 dB @ 1 GHz
(using a 030-00134-0001 RF Connector)
C. Attenuation of each TNC female panel mount connector is 0.06 dB @
1 GHZ (using a 030-00101-0002 RF Connector)
D. Attenuation of M17/128-RG 400 Coaxial Cable is 0.13 dB/ft @ 1 GHz
Using the above information, a RG 400 cable with a right angle TNC (antenna end) and a
straight TNC (KMH/KTA end) must be no longer than 22 feet long as measured from end
to end. If longer length is required, then a lower loss cable with appropriate connectors
must be selected. Reference the diagram below.
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NOTE
10609I00.ZIPCDL
KMH 880/KTA 870
Rev 0, October/2000