Sagetech XPC-TR User Manual - page 13
13
XP Transponders User Guide Rev 1.3
The antenna cable should have no more than 2dB of signal loss from the transponder to the antenna.
This includes losses in the connectors and cable. Generic and custom built cables can be obtained from
suppliers such as Pasternak, Richardson, and Aircraft Spruce.
Avoid sharp bends in the antenna cable that could lead to additional signal loss.
Static Pressure
The t a sdu e plu
s i to the ai aft’s stati p essu e sou e. This can be accomplished by plumbing
the altitude encoder connection to a static pressure line that shares the same source as the main aircraft
alti ete . The XP t a spo de se so a epts tu i g ith a i side dia ete of
o /
. Typically,
the tubing will need to be secured to the pressure transducer with a cable tie, clip or other suitable
method. However, in installations where the tubing is held in place by compression and is unlikely to
come lose (for example, a short, straight run of tubing between the transponder and a fitting held in a
fixed location), a mechanical fastener such as a cable tie may not be necessary.
If your installation requires cables ties, consider using something similar to Mouser part number 644-
PLT.6SM-M0.
In general, try to minimize the tubing length between the transducer and the static pressure system.
Your static pressure system may use 1.8mm,
.
,
, /
, /
, / " or other sized fittings.
Many aircraft installations use standard silicon tubing; e.g., Du-Bro part number 197m size medium,
available from radio control supply houses. Other systems use tubing from Cole Palmer (Tygon R-3603),
Beswick Engineering (part number MUT-1012), or McMaster-Carr (part numbers 5155T14or 5119K41). If
the tubing is stiff and needs to be stretched to fit on the pressure transducer, utilize needle nose pliers
as shown in Figure 1.
Figure 1
– Utilizing Needle Nose Pliers to Stretch Tubing
If you have to step up or step down in tubing size within your static pressure system, you can often slip
one hose inside another and secure this overlap with a clip, cable tie, or other suitable fastener. Some
flight computer vendors make custom step fittings.
A typical installation will have a T or Y fitting in the static pressure line with one end running to the
transponder. Suitable Y-barbed tube fittings are available from suppliers such as McMaster-Carr.