Pre-Installation: Existing Transponder System Check; Table 3-2: Pre-Installation Check Procedures - Garmin GDL 82 Installation Manual

3.3 Pre-Installation: Existing Transponder System Check

The existing Mode A/C (ATCRBS) transponder to be interfaced to the GDL 82, must meet the following:
•
The transponder complies with TSO-C74().
•
The installation of the transponder was previously FAA-Approved.
•
The existing transponder's altitude source (altitude serializer/encoder) must comply with TSO-
C10(), TSO-C106() or TSO-C88() and have prior FAA approval.
•
The transponder must pass the pre-installation check procedures in Table 3-2.
The existing transponder system's peak output power and receiver sensitivity must be verified to
determine compatibility with the GDL 82 before the system is installed in the aircraft. The GDL 82
introduces no more than 1.5 dB loss in the transmission line as measured at the antenna output.
Measurement is performed with a utilized radiated ramp tester, such as an Aeroflex IFR-6000 or TIC TR-
220, operated in accordance with the applicable operator's manual.
Step
Determine the RF Peak Output Power
and Receiver Sensitivity IAW Part 43,
Appendix F, for existing ATCRBS
1
system (i.e., transponder system).
Record the observed values of RF Peak
Output Power and Receiver Sensitivity.
Subtract the anticipated maximum loss
(1.5dB) from the peak output power and
2
add 1.5dB to the sensitivity values
determined in step 1.
Verify that the peak output power and
3 sensitivity are not reduced below the
required minimums.
Consider the following modifications to help reduce loss in the transponder system, if the results of the
procedure in Table 3-2 do NOT meet the minimum performance specifications of Part 43, Appendix F.
Any of the steps, or their combination, can be used.
NOTE
Performance of any or all of the following recommendations does not necessarily ensure
compliance with 14 CFR §43, Appendix F.
GDL 82 Mooney M20( ) Series STC Installation Manual

Table 3-2: Pre-Installation Check Procedures

Description
Page 10 of 49
Notes
RF Peak Output Power: ___________
Class A: > 21.0 dBw (125 Watts)
Class B: > 18.5 dBw (70 Watts)
Receiver Sensitivity (MTL): _____________
Any Class: MTL = -73 ±4 dBm
<Output Power>dBw - 1.5dB = _________dBw
<Sensitivity>dBm + 1.5dB = ___________dBm
Class A: > 21.0 dBw (125 Watts)
Class B: > 18.5 dBw (70 Watts)
Any Class: MTL = -73 ±4 dBm
190-01810-10
Rev. 1