TM 1-1510-223-10 Change 3          3-17 (b)   FH (frequency hopping mode).  This mode is the member versus master/controller mode of the fre- quency hopping mode of the VHF-FM transceiver. The data at the top center of the page is: Top line - 2-FM SETUP. Second line - The currently selected FH channel, the text NET, and the NET number. Third line - Displays FAIL, EMER, TUNING, or NO TSEC if appropriate. The display formats vary somewhat depending upon whether the aircraft is on the ground or in the air. 1    On the ground.   a L1.  Second depressions of L1 will cause the mode to change from SC to FH to FH/M, with the active mode boxed. NOTE If a TRANSEC variable has not been loaded, the text NO TSEC appears on the third line of text at the top center of the display. b L2.  The ERF RCV key is used to initiate reception of frequency hopping data from the NET controller’s radio. The received data is then stored in the member radio. Depressing L2 causes the legend to be boxed. If an ERF is received while the ERF RCV mode is  active,  the  text  at  L2  will  STORE  HSET  or  STORE LSET, followed by the HSET or LSET data that was re- ceived. Depressing L2 will store the LSET in its channel or the HSET data in the channel entered in the scratch- pad (valid entry is 1 through 6) and added to the HSET/ LSET list. If the received data is bad, the text BAD is displayed next to L2. If  the retrieval/storage of data is unsuccessful for some other reason, the text ERROR is displayed. c L3.   Function key L3 of the 2-FM SETUP page (FH format) is the HSET TUNE function key. This function key allows tuning of a hopset while on the 2-FM SETUP page. Pressing L3 to be tuned to the entered channel. If a channel number is entered which entered which does not contain a valid hopset and L3 is pressed, a scratchpad error will occur. NOTE The displayed HSET channel is the one that is used for LATE ENTRY. d L4.  The LSET CH key is used to display lockset data associated with a particular LSET channel. If the scratchpad is empty, depressing L4 will cause the current displayed LSET channel and code to be blanked from the display. If a valid LSET channel is scratchpadded,  depressing  L4  will  cause  the  scratch- padded channel and its LSET code to be displayed. Valid LSET  channels  are  1  through  6.  Other  possible  mes- sages are ERROR and NO LSET (no LSET loaded for that channel). e L5.    In  FH  mode,  this  function  is used to time FH operations. If the scratchpad is blank, depressing R5 will change the display of time stored in the transceiver. If time is not available from the transceiv- er,  the  display  remains  blank.  If  valid  data  is  scratch- padded, the data will be displayed adjacent to L5 and sent to the transceiver. Valid time data is day (0 through 99), hours (0 through 23), and minutes (0 through 59). Data fields not entered are considered zero. f R1.  Depressing R1 will cause the legend at R1 to be boxed and the transceiver to be put into the LATE NET E (entry) mode. The LATE NET mode can be used to resynchronize the radio to a net if commu- nication has been lost to drifting of the clock. g R3.    The  function  key  R3  of  the 2-FM SETUP page (FH format) is the CLEAR function key.  Pressing  R#  with  a  valid  hopset  (1-6)  or  lockset (L1-L8) channel number in the scratchpad will cause the associated hopset or lockset to be cleared from the radio. h Deleted. i Deleted.