use strict;
use warnings;
use Data::Dump::Streamer;

my %QSOs;

$QSOs{header} = '';

while (<DATA>) {
    $QSOs{header} .= $_;
    last if /<eoh>/;
}

my %qso;
my $key = '';

while (defined (my $line = <DATA>)) {
    chomp $line;
    next if ! length $line;
    
    next if ! ($line=~ /<qso_date:/ or length $key);
    if (! length $key) {
        $line=~ s/<qso_date:[^>]*>([^<]*)<time_on:[^>]*>([^<]*)(<?)/$3/;
        $key = "$1:$2";
    }
    
    my @fields = split '<', $line;
    
    for (@fields) {
        my ($tag, $text) = /([^>]*)>(.*)/;
        
        next if ! defined $tag or ! length $tag;
        
        if ($tag eq 'eor') {
            $QSOs{$key} = {%qso} if length $key;
            $key = '';
            %qso = ();
            last;
        }

        $qso{$tag} = $text || '';
    }
}

Dump (\%QSOs);

__DATA__
Exported by jLog (c)2006 LA3HM, V 3.90.2.7 according to ADIF <adif_ver:1>2
<PROGRAMID:4>jLog
For jLog info:
  mailto:mail@jlog.org
  http://jlog.org/
  Proposed ADIF2 Extensions may be included
<eoh>

<qso_date:8:d>20051029 <time_on:6>213400
<call:4>VC3O <band:3>20M <mode:3>SSB <operator:3>VHF
<rst_sent:2>59 <rst_rcvd:2>59

  <dxcc:1>1  <stx:1>4  <srx:1>4  <ituz:1>4  <cqz:1>4  <pfx:3>VC3  <cont:2>NA
  <freq:2>14  <qsoComplete:1>   <app_jlog_qso_number:4>0001
  <app_jlog_eqsl_qsl_sent:1>Y  <app_jlog_eqsl_qsl_rcvd:1>Y
  <app_jlog_lotw_qsl_sent:1>Y    <qsl_sent_via:1>E    <eor>

<qso_date:8:d>20060701 <time_on:6>183206
<call:5>VE6GG <band:3>20M <mode:3>SSB <operator:3>MWB
<rst_sent:2>59 <rst_rcvd:2>59

  <dxcc:1>1  <stx:2>27  <srx:2>AB  <ituz:1>2  <cqz:1>4  <contest_id:3>RAC
  <pfx:3>VE6  <cont:2>NA  <freq:8>14.16299  <state:2>AB  <qsoComplete:1>
  <app_jlog_qso_number:4>1257  <app_jlog_eqsl_qsl_sent:1>Y
  <app_jlog_eqsl_qslsdate:10>2006-07-01  <app_jlog_lotw_qsl_sent:1>Y
  <app_jlog_lotw_qslsdate:10>2006-07-01   <operator:4>N7DQ    <eor>