diff --git a/lib/hspec.f90 b/lib/hspec.f90
index b00e6bf70..e1377c3bc 100644
--- a/lib/hspec.f90
+++ b/lib/hspec.f90
@@ -71,7 +71,7 @@ subroutine hspec(id2,k,nutc0,ntrpdepth,nrxfreq,ntol,bmsk144,ingain,   &
   if(bmsk144) then
      if(k.ge.7168) then
         tsec=(k-7168)/12000.0
-        call mskrtd(id2(k-7168+1:k),nutc0,tsec,ntol,nrxfreq,line1)
+        call mskrtd(id2(k-7168+1:k),nutc0,tsec,ntol,nrxfreq,ndepth,line1)
      endif
   endif
 !###
diff --git a/lib/msk144d2.f90 b/lib/msk144d2.f90
index 8b6507bda..7df8fed18 100644
--- a/lib/msk144d2.f90
+++ b/lib/msk144d2.f90
@@ -18,7 +18,8 @@ program msk144d2
   character*12 mycall,hiscall
   character(len=500) optarg
 
-  type (option) :: long_options(7) = [ &
+  type (option) :: long_options(8) = [ &
+       option ('ndepth',.true.,'c','ndepth',''), &  
        option ('dxcall',.true.,'d','hiscall',''), &  
        option ('evemode',.true.,'e','',''), &
        option ('frequency',.true.,'f','rxfreq',''), &
@@ -28,6 +29,7 @@ program msk144d2
        option ('short',.false.,'s','enable Sh','') &
        ]
   t0=0.0
+  ndepth=3
   ntol=100
   nrxfreq=1500
   mycall=''
@@ -35,11 +37,13 @@ program msk144d2
   bShMsgs=.false.
  
   do
-     call getopt('d:ef:hm:n:s',long_options,c,optarg,narglen,nstat,noffset,nremain,.true.)
+     call getopt('c:d:ef:hm:n:s',long_options,c,optarg,narglen,nstat,noffset,nremain,.true.)
      if( nstat .ne. 0 ) then
         exit
      end if
      select case (c)
+     case ('c')
+        read (optarg(:narglen), *) ndepth 
      case ('d')
         read (optarg(:narglen), *) hiscall
      case ('e')
@@ -89,7 +93,7 @@ program msk144d2
      do i=1,npts,7*512
        ichunk=id2(i:i+7*1024-1)
        tsec=(i-1)/12000.0
-       call mskrtd(ichunk,nutc,tsec,ntol,nrxfreq,line)
+       call mskrtd(ichunk,nutc,tsec,ntol,nrxfreq,ndepth,line)
        if( index(line,"^") .ne. 0 .or. index(line,"&") .ne. 0 ) then
          write(*,*) line
        endif
diff --git a/lib/mskrtd.f90 b/lib/mskrtd.f90
index 8a725ca77..c24435094 100644
--- a/lib/mskrtd.f90
+++ b/lib/mskrtd.f90
@@ -1,4 +1,4 @@
-subroutine mskrtd(id2,nutc0,tsec,ntol,nrxfreq,line)
+subroutine mskrtd(id2,nutc0,tsec,ntol,nrxfreq,ndepth,line)
 
 ! Real-time decoder for MSK144.  
 ! Analysis block size = NZ = 7168 samples, t_block = 0.597333 s 
@@ -82,7 +82,7 @@ subroutine mskrtd(id2,nutc0,tsec,ntol,nrxfreq,line)
     endif
   enddo
   pavg=sum(pow)/8.0
- 
+
 ! Short ping decoder uses squared-signal spectrum to determine where to
 ! center a 3-frame analysis window and attempts to decode each of the 
 ! 3 frames along with 2- and 3-frame averages. 
@@ -94,9 +94,15 @@ subroutine mskrtd(id2,nutc0,tsec,ntol,nrxfreq,line)
     goto 999
   endif 
 
-! If short ping decoder doesn't find a decode, then 4-, 5-, and 7-frame averages
-! spanning the first 7 frames of the block.  
-  do iavg=1,NPATTERNS
+
+! If short ping decoder doesn't find a decode, 
+! Fast - try 4-frame averages only
+! Normal - try 4- and 5-frame averages
+! Deep - try 4-, 5- and 7-frame averages. 
+  npat=NPATTERNS
+  if( ndepth .eq. 1 ) npat=2
+  if( ndepth .eq. 2 ) npat=3
+  do iavg=1,npat
      iavmask=iavpatterns(1:8,iavg)
      navg=sum(iavmask)
      deltaf=7.0/real(navg)  ! search increment for frequency sync