diff --git a/CMakeLists.txt b/CMakeLists.txt
index 265270a62..505876daf 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -462,6 +462,7 @@ set (wsjt_FSRCS
   lib/geniscat.f90
   lib/fsk4hf/genfsk4hf.f90
   lib/ft8/genft8.f90
+  lib/ft8/genft8_174_91.f90
   lib/genmsk144.f90
   lib/genmsk40.f90
   lib/fsk4hf/genmskhf.f90
diff --git a/lib/ft8/ft8sim.f90 b/lib/ft8/ft8sim.f90
index a8bd49658..d6b62d7af 100644
--- a/lib/ft8/ft8sim.f90
+++ b/lib/ft8/ft8sim.f90
@@ -15,18 +15,18 @@ program ft8sim
   complex c(0:NMAX-1)
   real wave(NMAX)
   integer itone(NN)
-  integer*1 msgbits(KK)
+  integer*1 msgbits(91)
   integer*2 iwave(NMAX)                  !Generated full-length waveform
   data mygrid6/'EM48  '/
 
 ! Get command-line argument(s)
   nargs=iargc()
-  if(nargs.ne.8) then
-     print*,'Usage:    ft8sim "message"         nsig|f0  DT fdop del width nfiles snr'
-     print*,'Examples: ft8sim "K1ABC W9XYZ EN37" 1500.0 0.0  0.1 1.0   0     10   -18'
-     print*,'          ft8sim "K1ABC W9XYZ EN37"   10   0.0  0.1 1.0  25     10   -18'
-     print*,'          ft8sim "K1ABC W9XYZ EN37"   25   0.0  0.1 1.0  25     10   -18'
-     print*,'          ft8sim "K1ABC RR73; W9XYZ <KH1/KH7Z> -11" 300 0 0 0 25 1 -10'
+  if(nargs.ne.9) then
+     print*,'Usage:    ft8sim "message"         nsig|f0  DT fdop del width nfiles snr type'
+     print*,'Examples: ft8sim "K1ABC W9XYZ EN37" 1500.0 0.0  0.1 1.0   0     10   -18  1'
+     print*,'          ft8sim "K1ABC W9XYZ EN37"   10   0.0  0.1 1.0  25     10   -18  1'
+     print*,'          ft8sim "K1ABC W9XYZ EN37"   25   0.0  0.1 1.0  25     10   -18  1'
+     print*,'          ft8sim "K1ABC RR73; W9XYZ <KH1/KH7Z> -11" 300 0 0 0 25 1 -10  1'
      print*,'Make nfiles negative to invoke 72-bit contest mode.'
      go to 999
   endif
@@ -45,6 +45,9 @@ program ft8sim
   read(arg,*) nfiles                     !Number of files
   call getarg(8,arg)
   read(arg,*) snrdb                      !SNR_2500
+  call getarg(9,arg)
+  read(arg,*) itype                      !itype=1 for (174,87), itype=2 for (174,91)
+
   nsig=1
   if(f0.lt.100.0) then
      nsig=f0
@@ -69,7 +72,11 @@ program ft8sim
   if(index(msg40,';').le.0) then
      i3bit=0
      msg=msg40(1:22)
-     call genft8(msg,mygrid6,bcontest,i3bit,msgsent,msgbits,itone)
+     if(itype.eq.1) then
+        call genft8(msg,mygrid6,bcontest,i3bit,msgsent,msgbits,itone)
+     elseif(itype.eq.2) then
+        call genft8_174_91(msg,mygrid6,bcontest,i3bit,msgsent,msgbits,itone)
+     endif
      write(*,1000) f0,xdt,txt,snrdb,bw,msgsent
 1000 format('f0:',f9.3,'   DT:',f6.2,'   TxT:',f6.1,'   SNR:',f6.1,    &
           '  BW:',f4.1,2x,a22)
@@ -82,8 +89,13 @@ program ft8sim
 
   write(*,1030) msgbits(1:56)
 1030 format(/'Call1: ',28i1,'    Call2: ',28i1)
-  write(*,1032) msgbits(57:72),msgbits(73:75),msgbits(76:87)
+  if(itype.eq.1) then
+     write(*,1032) msgbits(57:72),msgbits(73:75),msgbits(76:87)
 1032 format('Grid:  ',16i1,'   3Bit: ',3i1,'    CRC12: ',12i1)
+  elseif(itype.eq.2) then
+     write(*,1033) msgbits(57:72),msgbits(73:77),msgbits(78:91)
+1033 format('Grid:  ',16i1,'  5Bit: ',5i1,'   CRC14: ',14i1)
+  endif
   write(*,1034) itone
 1034 format(/'Channel symbols:'/79i1/)
 
@@ -99,7 +111,11 @@ program ft8sim
            if(isig.eq.2) then
               f0=f0+100
            endif
-           call genft8(msg,mygrid6,bcontest,i3bit,msgsent,msgbits,itone)
+           if(itype.eq.1) then
+              call genft8(msg,mygrid6,bcontest,i3bit,msgsent,msgbits,itone)
+           elseif(itype.eq.2) then
+              call genft8_174_91(msg,mygrid6,bcontest,i3bit,msgsent,msgbits,itone)
+           endif
         endif
         if(nsig.eq.25) then
            f0=(isig+2)*100.0
@@ -118,7 +134,11 @@ program ft8sim
 1002          format('R',i3.2)
               f0=600.0 + mod(isig-1,5)*60.0
            endif
-           call genft8(msg,mygrid6,bcontest,i3bit,msgsent,msgbits,itone)
+           if(itype.eq.1) then
+              call genft8(msg,mygrid6,bcontest,i3bit,msgsent,msgbits,itone)
+           elseif(itype.eq.2) then
+              call genft8_174_91(msg,mygrid6,bcontest,i3bit,msgsent,msgbits,itone)
+           endif
         endif
         k=-1 + nint((xdt+0.5+0.01*gran())/dt)
 !        k=-1 + nint((xdt+0.5)/dt)
diff --git a/lib/ft8/genft8_174_91.f90 b/lib/ft8/genft8_174_91.f90
new file mode 100644
index 000000000..d6f98f284
--- /dev/null
+++ b/lib/ft8/genft8_174_91.f90
@@ -0,0 +1,53 @@
+subroutine genft8_174_91(msg,mygrid,bcontest,i5bit,msgsent,msgbits,itone)
+
+! Encode an FT8 message, producing array itone().
+  
+  use crc
+  use packjt
+  include 'ft8_params.f90'
+  character*22 msg,msgsent
+  character*6 mygrid
+  character*91 cbits
+  logical bcontest,checksumok
+  integer*4 i4Msg6BitWords(12)                !72-bit message as 6-bit words
+  integer*1 msgbits(91),codeword(174)
+  integer*1, target:: i1Msg8BitBytes(12)
+  integer itone(79)
+  integer icos7(0:6)
+#  data icos7/2,5,6,0,4,1,3/                   !Costas 7x7 tone pattern
+  data icos7/3,1,4,0,6,5,2/                   !Costas 7x7 tone pattern
+
+  call packmsg(msg,i4Msg6BitWords,itype,bcontest) !Pack into 12 6-bit bytes
+  call unpackmsg(i4Msg6BitWords,msgsent,bcontest,mygrid) !Unpack to get msgsent
+
+  write(cbits,1000) i4Msg6BitWords,8*i5bit
+1000 format(12b6.6,b8.8)
+  read(cbits,1001) i1Msg8BitBytes(1:10)
+1001 format(10b8)
+  i1Msg8BitBytes(10)=iand(i1Msg8BitBytes(10),128+64+32+16+8)
+  i1Msg8BitBytes(11:12)=0
+  icrc14=crc14(c_loc(i1Msg8BitBytes),12)
+  i1Msg8BitBytes(11)=icrc14/256
+  i1Msg8BitBytes(12)=iand (icrc14,255)
+
+  write(cbits,1003) i4Msg6BitWords,i5bit,icrc14
+1003 format(12b6.6,b5.5,b14.14)
+  read(cbits,1004) msgbits
+1004 format(91i1)
+
+  call encode174_91(msgbits,codeword)      !Encode the test message
+
+! Message structure: S7 D29 S7 D29 S7
+  itone(1:7)=icos7
+  itone(36+1:36+7)=icos7
+  itone(NN-6:NN)=icos7
+  k=7
+  do j=1,ND
+     i=3*j -2
+     k=k+1
+     if(j.eq.30) k=k+7
+     itone(k)=codeword(i)*4 + codeword(i+1)*2 + codeword(i+2)
+  enddo
+
+  return
+end subroutine genft8_174_91