Trigger 20 Description

Sequence: C2 (Antenna Deployment)
Trigger 20 (Electric Antenna Checkout)
This mode is part of the antenna deployment checkout. It runs internal to the instrument, switching the receivers to each electric antenna.
This trigger last for about 5 minutes. The HFR is suppose to be collected in default mode during the Antenna checkout part of this trigger (however, during the initial uses of this trigger in flight, the HFR did not collect data
(see comment below). After the Antenna checkout ends, the instrument internally executes Trigger 30. LFR, MFR, WBR and WFR data ARE collected during this trigger, with the MFR toggling between EX options (EU, EV, EX) and EW.
The internal sequence of this trigger is:

Operation                               Duration
-------------------------               ----------
MFR Antennas OFF                        75 seconds
MFR Antennas Ex+, Ez ON                 75 seconds
MFR Antennas Ex-, Ez ON                 75 seconds
MFR Antennas Ex+/-, Ez ON               75 seconds
Enter Trigger 30 Mode

During the initial inflight use of Trigger 10, 20, and 30 (during the antenna deployment in C2), the HFR did NOT go into the expected mode due to a software feature between the HFR and the order that the HFR commands were issued from the onboard sequence and the IEB (see ISA Z44412 for a discussion of this issue and the solutions implemented to prevent this from occurring in future sequences.
This problem only occurred during the antenna deployment sequence, and not when the Triggers were sent individually.
Comments have been added to the C2 timeline to note which periods had Triggers that did not operate as expected. The primary affect of this problem was that Trigger 30 did NOT put the HFR in the expected mode at the end of Trigger 10 and 20 (the HFR stayed, or entered its default mode).
Furthermore, for the first two uses of Trigger 20 (1997-298T00:15 and 03:38), the HFR collected no data during the internal Antenna checkout part of the trigger, resulting in no HFR data for about five minutes.

Receiver Frequency Range Sensors Time between Snapshots
LFR 1 - 25 Hz EX, EW
 16 seconds
MFR 25 - 12 kHz Cycles, EW
 32 seconds
WFR .1 - 2.5 kHz EX, EW, BX, BY, BZ 25 seconds
WBR
 0 - 80 kHz
 EW
 8 seconds
HFR 3.6 KHz - 16 MHz EX, EW
 24 seconds


The HFR is in the following 'default' mode during this trigger.
This mode is defined by:
          Correlations     Channels        Integ.                Size Frequency
Band Ant. Auto-  Cross-    per Band   df   Period    Rep   Steps kHz  Start - Stop
---- ---- -----  ------    --------   --   ------    ---   ----- ---- ------------
ABC  2E     y      y          32       n    1000      1                3.6-319 kHz
H1   2E     y      y           4       n     160      1     70     25  250k-1.975MHz
H2   2E     y      y           1       n      80      1     70    200  2.025M-15.825MHz

Bands ABC require 3.12 sec to complete, H1 requires 12.30 sec, and H2 requires 6.27 sec for a total of about 21.7 sec per sweep. However, the time between analyses is set to 24 seconds.