module q65 parameter (NSTEP=8) !Number of time bins per symbol in s1, s1a, s1b parameter (PLOG_MIN=-242.0) !List decoding threshold integer nsave,nlist,LL0,iz0,jz0 integer listutc(10) integer apsym0(58),aph10(10) integer apmask1(78),apsymbols1(78) integer apmask(13),apsymbols(13) integer,dimension(22) :: isync = (/1,9,12,13,15,22,23,26,27,33,35, & 38,46,50,55,60,62,66,69,74,76,85/) integer codewords(63,206) integer ibwa,ibwb,ncw,nsps,mode_q65,nfa,nfb,nqd integer idfbest,idtbest,ibw,ndistbest,maxiters,max_drift integer istep,nsmo,lag1,lag2,npasses,nused,iseq,ncand,nrc integer i0,j0 integer navg(0:1) logical lnewdat real candidates(20,3) !snr, xdt, and f0 of top candidates real, allocatable :: s1raw(:,:) !Symbol spectra, 1/8-symbol steps real, allocatable :: s1(:,:) !Symbol spectra w/suppressed peaks real, allocatable,save :: s1a(:,:,:) !Cumulative symbol spectra real, allocatable,save :: ccf2(:) !Max CCF(freq) at any lag, single seq real, allocatable,save :: ccf2_avg(:) !Like ccf2, but for accumulated average real sync(85) !sync vector real df,dtstep,dtdec,f0dec,ftol,plog,drift contains subroutine q65_dec0(iavg,nutc,iwave,ntrperiod,nfqso,ntol,ndepth,lclearave, & emedelay,xdt,f0,snr1,width,dat4,snr2,idec) ! Top-level routine in q65 module ! - Compute symbol spectra ! - Attempt sync and q3 decode using all 85 symbols ! - If that fails, try sync with 22 symbols and standard q[0124] decode ! Input: iavg 0 for single-period decode, 1 for average ! iwave(0:nmax-1) Raw data ! ntrperiod T/R sequence length (s) ! nfqso Target frequency (Hz) ! ntol Search range around nfqso (Hz) ! ndepth Requested decoding depth ! lclearave Flag to clear the accumulating array ! emedelay Extra delay for EME signals ! Output: xdt Time offset from nominal (s) ! f0 Frequency of sync tone ! snr1 Relative SNR of sync signal ! width Estimated Doppler spread ! dat4(13) Decoded message as 13 six-bit integers ! snr2 Estimated SNR of decoded signal ! idec Flag for decoding results ! -1 No decode ! 0 No AP ! 1 "CQ ? ?" ! 2 "Mycall ? ?" ! 3 "MyCall HisCall ?" use packjt77 use timer_module, only: timer parameter (LN=2176*63) !LN=LL*NN; LL=64*(mode_q65+2), NN=63 integer*2 iwave(0:12000*ntrperiod-1) !Raw data integer dat4(13) character*37 decoded logical first,lclearave real, allocatable :: s3(:,:) !Data-symbol energies s3(LL,63) real, allocatable :: ccf1(:) !CCF(freq) at fixed lag (red) data first/.true./ save first NN=63 if(nutc+ndepth.eq.-999) stop !Silence compiler warnings ! Set some parameters and allocate storage for large arrays irc=-2 nrc=-2 idec=-1 snr1=0. dat4=0 LL=64*(2+mode_q65) nfft=nsps df=12000.0/nfft !Freq resolution = baud istep=nsps/NSTEP iz=5000.0/df !Uppermost frequency bin, at 5000 Hz txt=85.0*nsps/12000.0 jz=(txt+1.0)*12000.0/istep !Number of symbol/NSTEP bins if(nsps.ge.6912) jz=(txt+2.0)*12000.0/istep !For TR 60 s and higher ftol=ntol ia=ntol/df ia2=max(ia,10*mode_q65,nint(100.0/df)) nsmo=int(0.7*mode_q65*mode_q65) if(nsmo.lt.1) nsmo=1 if(first) then !Generate the sync vector sync=-22.0/63.0 !Sync tone OFF do k=1,22 sync(isync(k))=1.0 !Sync tone ON enddo endif allocate(s3(-64:LL-65,63)) allocate(ccf1(-ia2:ia2)) if(LL.ne.LL0 .or. iz.ne.iz0 .or. jz.ne.jz0 .or. lclearave) then if(allocated(s1raw)) deallocate(s1raw) allocate(s1raw(iz,jz)) if(allocated(s1)) deallocate(s1) allocate(s1(iz,jz)) if(allocated(s1a)) deallocate(s1a) allocate(s1a(iz,jz,0:1)) if(allocated(ccf2)) deallocate(ccf2) allocate(ccf2(iz)) if(allocated(ccf2_avg)) deallocate(ccf2_avg) allocate(ccf2_avg(iz)) s1=0. s1a=0. navg=0 LL0=LL iz0=iz jz0=jz lclearave=.false. endif ccf1=0. if(iavg.eq.0) ccf2_avg=0. dtstep=nsps/(NSTEP*12000.0) !Step size in seconds lag1=-1.0/dtstep lag2=1.0/dtstep + 0.9999 if(nsps.ge.3600 .and. emedelay.gt.0) lag2=5.5/dtstep + 0.9999 !Include EME j0=0.5/dtstep if(nsps.ge.7200) j0=1.0/dtstep !Nominal start-signal index s3=0. if(iavg.eq.0) then call timer('q65_syms',0) ! Compute symbol spectra with NSTEP time bins per symbol call q65_symspec(iwave,ntrperiod*12000,iz,jz,s1) call timer('q65_syms',1) else s1=s1a(:,:,iseq) endif i0=nint(nfqso/df) !Target QSO frequency ii1=max(1,i0-64) ii2=i0-65+LL call pctile(s1(ii1:ii2,1:jz),ii2-ii1+1*jz,45,base) s1=s1/base s1raw=s1 ! Apply fast AGC to the symbol spectra s1max=20.0 !Empirical choice do j=1,jz !### Maybe wrong way? ### smax=maxval(s1(ii1:ii2,j)) if(smax.gt.s1max) s1(ii1:ii2,j)=s1(ii1:ii2,j)*s1max/smax enddo dat4=0 if(ncw.gt.0 .and. iavg.le.1) then ! Try list decoding via "Deep Likelihood". call timer('ccf_85 ',0) ! Try to synchronize using all 85 symbols call q65_ccf_85(s1,iz,jz,nfqso,ia,ia2,ipk,jpk,f0,xdt,imsg_best,ccf1) call timer('ccf_85 ',1) call timer('list_dec',0) call q65_dec_q3(s1,iz,jz,s3,LL,ipk,jpk,snr2,dat4,idec,decoded) call timer('list_dec',1) ! If idec=3 we have a q3 decode. Continue to compute sync curve for plotting. endif ! Get 2d CCF and ccf2 using sync symbols only if(iavg.eq.0) then call timer('ccf_22a ',0) call q65_ccf_22(s1,iz,jz,nfqso,ntol,ndepth,ntrperiod,iavg,ipk,jpk, & f0a,xdta,ccf2) call timer('ccf_22a ',1) endif ! Get 2d CCF and ccf2_avg using sync symbols only if(iavg.ge.1) then call timer('ccf_22b ',0) call q65_ccf_22(s1,iz,jz,nfqso,ntol,ndepth,ntrperiod,iavg,ipk,jpk, & f0a,xdta,ccf2_avg) call timer('ccf_22b ',1) endif if(idec.lt.0) then f0=f0a xdt=xdta endif ! Estimate rms on ccf2 baseline call q65_sync_curve(ccf2,1,iz,rms2) smax=maxval(ccf2) snr1=0. if(rms2.gt.0) snr1=smax/rms2 if(idec.le.0) then ! The q3 decode attempt failed. Copy synchronized symbol energies from s1 ! into s3 and prepare to try a more general decode. call q65_s1_to_s3(s1,iz,jz,ipk,jpk,LL,mode_q65,sync,s3) endif smax=maxval(ccf1) ! Estimate frequency spread i1=-9999 i2=-9999 do i=-ia,ia if(i1.eq.-9999 .and. ccf1(i).ge.0.5*smax) i1=i if(i2.eq.-9999 .and. ccf1(-i).ge.0.5*smax) i2=-i enddo width=df*(i2-i1) if(ncw.eq.0) ccf1=0. call q65_write_red(iz,xdt,ccf2_avg,ccf2) if(idec.lt.0 .and. (iavg.eq.0 .or. iavg.eq.2)) then call q65_dec_q012(s3,LL,snr2,dat4,idec,decoded) endif 900 return end subroutine q65_dec0 subroutine q65_clravg ! Clear the averaging array to start a new average. if(allocated(s1a)) s1a(:,:,iseq)=0. navg(iseq)=0 return end subroutine q65_clravg subroutine q65_symspec(iwave,nmax,iz,jz,s1) ! Compute symbol spectra with NSTEP time-steps per symbol. integer*2 iwave(0:nmax-1) !Raw data real s1(iz,jz) complex, allocatable :: c0(:) !Complex spectrum of symbol allocate(c0(0:nsps-1)) nfft=nsps fac=1/32767.0 do j=1,jz !Compute symbol spectra at step size i1=(j-1)*istep i2=i1+nsps-1 k=-1 do i=i1,i2,2 !Load iwave data into complex array c0, for r2c FFT xx=iwave(i) yy=iwave(i+1) k=k+1 c0(k)=fac*cmplx(xx,yy) enddo c0(k+1:)=0. call four2a(c0,nfft,1,-1,0) !r2c FFT do i=1,iz s1(i,j)=real(c0(i))**2 + aimag(c0(i))**2 enddo ! For large Doppler spreads, should we smooth the spectra here? if(nsmo.le.1) nsmo=0 do i=1,nsmo call smo121(s1(1:iz,j),iz) enddo enddo if(lnewdat) then navg(iseq)=navg(iseq) + 1 ntc=min(navg(iseq),4) !Averaging time constant in sequences u=1.0/ntc s1a(:,:,iseq)=u*s1 + (1.0-u)*s1a(:,:,iseq) endif return end subroutine q65_symspec subroutine q65_dec_q3(s1,iz,jz,s3,LL,ipk,jpk,snr2,dat4,idec,decoded) ! Copy synchronized symbol energies from s1 into s3, then attempt a q3 decode. character*37 decoded integer dat4(13) real s1(iz,jz) real s3(-64:LL-65,63) call q65_s1_to_s3(s1,iz,jz,ipk,jpk,LL,mode_q65,sync,s3) nsubmode=0 if(mode_q65.eq.2) nsubmode=1 if(mode_q65.eq.4) nsubmode=2 if(mode_q65.eq.8) nsubmode=3 if(mode_q65.eq.16) nsubmode=4 if(mode_q65.eq.32) nsubmode=5 baud=12000.0/nsps do ibw=ibwa,ibwb b90=1.72**ibw b90ts=b90/baud call q65_dec1(s3,nsubmode,b90ts,esnodb,irc,dat4,decoded) nrc=irc if(irc.ge.0) then snr2=esnodb - db(2500.0/baud) + 3.0 !Empirical adjustment idec=3 exit endif enddo return end subroutine q65_dec_q3 subroutine q65_dec_q012(s3,LL,snr2,dat4,idec,decoded) ! Do separate passes attempting q0, q1, q2 decodes. character*37 decoded character*78 c78 integer dat4(13) real s3(-64:LL-65,63) logical lapcqonly nsubmode=0 if(mode_q65.eq.2) nsubmode=1 if(mode_q65.eq.4) nsubmode=2 if(mode_q65.eq.8) nsubmode=3 if(mode_q65.eq.16) nsubmode=4 baud=12000.0/nsps iaptype=0 nQSOprogress=0 !### TEMPORARY ? ### ncontest=0 lapcqonly=.false. do ipass=0,npasses !Loop over AP passes apmask=0 !Try first with no AP information apsymbols=0 if(ipass.ge.1) then ! Subsequent passes use AP information appropiate for nQSOprogress call q65_ap(nQSOprogress,ipass,ncontest,lapcqonly,iaptype, & apsym0,apmask1,apsymbols1) write(c78,1050) apmask1 1050 format(78i1) read(c78,1060) apmask 1060 format(13b6.6) write(c78,1050) apsymbols1 read(c78,1060) apsymbols endif do ibw=ibwa,ibwb b90=1.72**ibw b90ts=b90/baud call q65_dec2(s3,nsubmode,b90ts,esnodb,irc,dat4,decoded) nrc=irc if(irc.ge.0) then snr2=esnodb - db(2500.0/baud) + 3.0 !Empirical adjustment idec=iaptype go to 100 endif enddo enddo 100 return end subroutine q65_dec_q012 subroutine q65_ccf_85(s1,iz,jz,nfqso,ia,ia2,ipk,jpk,f0,xdt,imsg_best,ccf1) ! Attempt synchronization using all 85 symbols, in advance of an ! attempt at q3 decoding. Return ccf1 for the "red sync curve". real s1(iz,jz) real, allocatable :: ccf(:,:) !CCF(freq,lag) real ccf1(-ia2:ia2) integer ijpk(2) integer itone(85) allocate(ccf(-ia2:ia2,-53:214)) ipk=0 jpk=0 ccf_best=0. imsg_best=-1 do imsg=1,ncw i=1 k=0 do j=1,85 if(j.eq.isync(i)) then i=i+1 itone(j)=0 else k=k+1 itone(j)=codewords(k,imsg) + 1 endif enddo ! Compute 2D ccf using all 85 symbols in the list message ccf=0. iia=200.0/df do lag=lag1,lag2 do k=1,85 j=j0 + NSTEP*(k-1) + 1 + lag if(j.ge.1 .and. j.le.jz) then do i=-ia2,ia2 ii=i0+mode_q65*itone(k)+i if(ii.ge.iia .and. ii.le.iz) ccf(i,lag)=ccf(i,lag) + s1(ii,j) enddo endif enddo enddo ccfmax=maxval(ccf(-ia:ia,:)) if(ccfmax.gt.ccf_best) then ccf_best=ccfmax ijpk=maxloc(ccf(-ia:ia,:)) ipk=ijpk(1)-ia-1 jpk=ijpk(2)-53-1 f0=nfqso + ipk*df xdt=jpk*dtstep imsg_best=imsg ccf1=ccf(:,jpk) endif enddo ! imsg deallocate(ccf) return end subroutine q65_ccf_85 subroutine q65_ccf_22(s1,iz,jz,nfqso,ntol,ndepth,ntrperiod,iavg,ipk,jpk, & f0,xdt,ccf2) ! Attempt synchronization using only the 22 sync symbols. Return ccf2 ! for the "orange sync curve". real s1(iz,jz) real ccf2(iz) !Orange sync curve real, allocatable :: xdt2(:) real, allocatable :: s1avg(:) integer, allocatable :: indx(:) allocate(xdt2(iz)) allocate(s1avg(iz)) allocate(indx(iz)) ia=max(nfa,100)/df ib=min(nfb,4900)/df if(nqd.ne.1 .or. iavg.ne.0) max_drift=0 if(max_drift.ne.0) then ia=max(nint(100/df),nint((nfqso-ntol)/df)) ib=min(nint(4900/df),nint((nfqso+ntol)/df)) endif do i=ia,ib s1avg(i)=sum(s1(i,1:jz)) enddo ccfbest=0. ibest=0 lagpk=0 lagbest=0 idrift_best=0 do i=ia,ib ccfmax=0. do lag=lag1,lag2 do idrift=-max_drift,max_drift ccft=0. do kk=1,22 k=isync(kk) ii=i + nint(idrift*(k-43)/85.0) if(ii.lt.1 .or. ii.gt.iz) cycle n=NSTEP*(k-1) + 1 j=n+lag+j0 if(j.ge.1 .and. j.le.jz) ccft=ccft + s1(ii,j) enddo ! kk ccft=ccft - (22.0/jz)*s1avg(i) if(ccft.gt.ccfmax) then ccfmax=ccft lagpk=lag idrift_max=idrift endif enddo ! idrift enddo ! lag ccf2(i)=ccfmax xdt2(i)=lagpk*dtstep if(ccfmax.gt.ccfbest .and. abs(i*df-nfqso).le.ftol) then ccfbest=ccfmax ibest=i lagbest=lagpk idrift_best=idrift_max endif enddo ! i ! Parameters for the top candidate: ipk=ibest - i0 jpk=lagbest f0=nfqso + ipk*df xdt=jpk*dtstep drift=df*idrift_best ccf2(:ia)=0. ccf2(ib:)=0. ! Save parameters for best candidates jzz=ib-ia+1 call pctile(ccf2(ia:ib),jzz,40,base) ccf2=ccf2/base call indexx(ccf2(ia:ib),jzz,indx) ncand=0 maxcand=20 do j=1,20 k=jzz-j+1 if(k.lt.1 .or. k.gt.iz) cycle i=indx(k)+ia-1 if(ccf2(i).lt.3.3) exit !Candidate limit f=i*df if(f.ge.(nfqso-ftol) .and. f.le.(nfqso+ftol)) cycle !Looked here already i3=max(1, i-mode_q65) i4=min(iz,i+mode_q65) biggest=maxval(ccf2(i3:i4)) if(ccf2(i).ne.biggest) cycle ncand=ncand+1 candidates(ncand,1)=ccf2(i) candidates(ncand,2)=xdt2(i) candidates(ncand,3)=f if(ncand.ge.maxcand) exit enddo return end subroutine q65_ccf_22 subroutine q65_dec1(s3,nsubmode,b90ts,esnodb,irc,dat4,decoded) ! Attmpt a full-AP list decode. use packjt77 real s3(1,1) !Silence compiler warning that wants to see a 2D array real s3prob(0:63,63) !Symbol-value probabilities integer dat4(13) character c77*77,decoded*37 logical unpk77_success nFadingModel=1 decoded=' ' call q65_intrinsics_ff(s3,nsubmode,b90ts,nFadingModel,s3prob) call q65_dec_fullaplist(s3,s3prob,codewords,ncw,esnodb,dat4,plog,irc) if(sum(dat4).le.0) irc=-2 if(irc.ge.0 .and. plog.gt.PLOG_MIN) then write(c77,1000) dat4(1:12),dat4(13)/2 1000 format(12b6.6,b5.5) call unpack77(c77,0,decoded,unpk77_success) !Unpack to get msgsent else irc=-1 endif nrc=irc return end subroutine q65_dec1 subroutine q65_dec2(s3,nsubmode,b90ts,esnodb,irc,dat4,decoded) ! Attempt a q0, q1, or q2 decode using spcified AP information. use packjt77 real s3(iz0,jz0) !Silence compiler warning that wants to see a 2D array real s3prob(0:63,63) !Symbol-value probabilities integer dat4(13) character c77*77,decoded*37 logical unpk77_success nFadingModel=1 decoded=' ' call q65_intrinsics_ff(s3,nsubmode,b90ts,nFadingModel,s3prob) call q65_dec(s3,s3prob,APmask,APsymbols,maxiters,esnodb,dat4,irc) if(sum(dat4).le.0) irc=-2 nrc=irc if(irc.ge.0) then write(c77,1000) dat4(1:12),dat4(13)/2 1000 format(12b6.6,b5.5) call unpack77(c77,0,decoded,unpk77_success) !Unpack to get msgsent endif return end subroutine q65_dec2 subroutine q65_s1_to_s3(s1,iz,jz,ipk,jpk,LL,mode_q65,sync,s3) ! Copy synchronized symbol energies from s1 (or s1a) into s3. real s1(iz,jz) real s3(-64:LL-65,63) real sync(85) !sync vector i1=i0+ipk-64 + mode_q65 i2=i1+LL-1 if(i1.ge.1 .and. i2.le.iz) then j=j0+jpk-7 n=0 do k=1,85 j=j+8 if(sync(k).gt.0.0) then cycle endif n=n+1 if(j.ge.1 .and. j.le.jz) s3(-64:LL-65,n)=s1(i1:i2,j) enddo endif call q65_bzap(s3,LL) !Zap birdies return end subroutine q65_s1_to_s3 subroutine q65_write_red(iz,xdt,ccf2_avg,ccf2) ! Write data for the red and orange sync curves to LU 17. real ccf2_avg(iz) real ccf2(iz) call q65_sync_curve(ccf2_avg,1,iz,rms1) call q65_sync_curve(ccf2,1,iz,rms2) rewind 17 write(17,1000) xdt,minval(ccf2_avg),maxval(ccf2_avg) do i=max(1,nint(nfa/df)),min(iz,int(nfb/df)) freq=i*df y1=ccf2_avg(i) if(y1.gt.10.0) y1=10.0 + 2.0*log10(y1/10.0) y2=ccf2(i) if(y2.gt.10.0) y2=10.0 + 2.0*log10(y2/10.0) write(17,1000) freq,y1,y2 1000 format(3f10.3) enddo flush(17) return end subroutine q65_write_red subroutine q65_sync_curve(ccf1,ia,ib,rms1) ! Condition the red or orange sync curve for plotting. real ccf1(ia:ib) ic=(ib-ia)/8; nsum=2*(ic+1) base1=(sum(ccf1(ia:ia+ic)) + sum(ccf1(ib-ic:ib)))/nsum ccf1=ccf1-base1 sq=dot_product(ccf1(ia:ia+ic),ccf1(ia:ia+ic)) + & dot_product(ccf1(ib-ic:ib),ccf1(ib-ic:ib)) rms1=0. if(nsum.gt.0) rms1=sqrt(sq/nsum) if(rms1.gt.0.0) ccf1=ccf1/rms1 ! smax1=maxval(ccf1) ! if(smax1.gt.10.0) ccf1=10.0*ccf1/smax1 return end subroutine q65_sync_curve subroutine q65_bzap(s3,LL) parameter (NBZAP=15) real s3(-64:LL-65,63) integer ipk1(1) integer, allocatable :: hist(:) allocate(hist(-64:LL-65)) hist=0 do j=1,63 ipk1=maxloc(s3(:,j)) i=ipk1(1) - 65 hist(i)=hist(i)+1 enddo if(maxval(hist).gt.NBZAP) then do i=-64,LL-65 if(hist(i).gt.NBZAP) s3(i,1:63)=1.0 enddo endif return end subroutine q65_bzap subroutine q65_snr(dat4,dtdec,f0dec,mode_q65,nused,snr2) ! Estimate SNR of a decoded transmission by aligning the spectra of ! all 85 symbols. integer dat4(13) integer codeword(63) integer itone(85) real, allocatable :: spec(:) allocate(spec(iz0)) call q65_enc(dat4,codeword) i=1 k=0 do j=1,85 if(j.eq.isync(i)) then i=i+1 itone(j)=0 else k=k+1 itone(j)=codeword(k) + 1 endif enddo spec=0. lagpk=nint(dtdec/dtstep) do k=1,85 j=j0 + NSTEP*(k-1) + 1 + lagpk if(j.ge.1 .and. j.le.jz0) then do i=1,iz0 ii=i+mode_q65*itone(k) if(ii.ge.1 .and. ii.le.iz0) spec(i)=spec(i) + s1raw(ii,j) enddo endif enddo i0=nint(f0dec/df) nsum=max(10*mode_q65,nint(50.0/df)) ia=max(1,i0-2*nsum) ib=min(iz0,i0+2*nsum) sum1=sum(spec(ia:ia+nsum-1)) sum2=sum(spec(ib-nsum+1:ib)) avg=(sum1+sum2)/(2.0*nsum) spec=spec/avg !Baseline level is now 1.0 smax=maxval(spec(ia:ib)) sig_area=sum(spec(ia+nsum:ib-nsum)-1.0) w_equiv=sig_area/(smax-1.0) snr2=db(max(1.0,sig_area)) - db(2500.0/df) if(nused.eq.2) snr2=snr2 - 2.0 if(nused.eq.3) snr2=snr2 - 2.9 if(nused.ge.4) snr2=snr2 - 3.5 return end subroutine q65_snr subroutine q65_hist(if0,msg0,dxcall,dxgrid) ! Save the MAXHIST most receent decodes, and their f0 values; or, if ! dxcall is present, look up the most recent dxcall and dxgrid at the ! specified f0. parameter (MAXHIST=100) integer,intent(in) :: if0 !Audio freq of decode character(len=37),intent(in),optional :: msg0 !Decoded message character(len=12),intent(out),optional :: dxcall !Second callsign in message character(len=6),intent(out),optional :: dxgrid !Third word in msg, if grid character*6 g1 character*37 msg(MAXHIST) !Saved messages integer nf0(MAXHIST) !Saved frequencies logical isgrid !Statement function data nhist/0/ save nhist,nf0,msg isgrid(g1)=g1(1:1).ge.'A' .and. g1(1:1).le.'R' .and. g1(2:2).ge.'A' .and. & g1(2:2).le.'R' .and. g1(3:3).ge.'0' .and. g1(3:3).le.'9' .and. & g1(4:4).ge.'0' .and. g1(4:4).le.'9' .and. g1(1:4).ne.'RR73' if(present(dxcall)) go to 100 !This is a lookup request if(nhist.eq.MAXHIST) then nf0(1:MAXHIST-1)=nf0(2:MAXHIST) !List is full, must make room msg(1:MAXHIST-1)=msg(2:MAXHIST) nhist=MAXHIST-1 endif nhist=nhist+1 !Insert msg0 at end of list nf0(nhist)=if0 msg(nhist)=msg0 go to 900 100 if(dxcall(1:3).ne.' ') go to 900 dxcall=' ' !This is a lookup request dxgrid=' ' ! Look for a decode close to if0, starting with most recent ones do i=nhist,1,-1 if(abs(nf0(i)-if0).gt.10) cycle i1=index(msg(i),' ') if(i1.ge.4 .and. i1.le.13) then i2=index(msg(i)(i1+1:),' ') + i1 dxcall=msg(i)(i1+1:i2-1) !Extract dxcall g1=msg(i)(i2+1:i2+4) if(isgrid(g1)) dxgrid=g1(1:4) !Extract dxgrid exit endif enddo 900 return end subroutine q65_hist end module q65